A review by Aaron Shell

Aircraft Specs

»Load capacity: 500g-800g (claimed)

»Battery Requirements: 3 cell 2200mAh-4000mAh LiPo

»Included Electronics: 3 Axis MEMS Gyros, 3 Axis MEMS Accelerometers, and barometric pressure sensor integrated into main flight control board. Compatible with most 4 or more channel RC aircraft systems (FM, PCM, 2.4 GHz, etc)

Speed Controllers: (4 on 2 stacked boards): I2C 12 amp brushless ESCs

»Best Load: 500g (claimed)
»Landing Gear Width: 580mm
»Length: 610mm
»Width: 610mm
»Height: 235mm
»Weight: 730g (without battery, receiver, camera etc.)

Components Used On Aircraft

»Control Receiver: Futaba R608FS 2.4GHz FASST 8 channel

»Battery: 2,200 mAh 3 cell LiPo

»Camera: OCSC 420 CCD camera

»Video Transmitter: 100mw 1.28 gHz from readymaderc.com with homemade dipole, later switched to a Cloverleaf

»Video battery: 500 mAh 3 cell LiPo

Components Used on Ground Station

»Control Transmitter: Futaba 12FG Transmitter with 2.4GHz FASST module

»Video Goggles: Hacked Trimersion goggles

»Video Receiver: 12 channel digital display 900-1.3 gHz video receiver with homemade Skew-Planar antenna

»Video splitter: Eagle Tree Systems Eagle Eyes

»Video recorder: Aiptek DV5800

Out of the Box

When you open the box the biggest attention grabber is the impression of a finished, quality product; the airframe is made up of a plastic center body which has a very nice matte finish, and aluminum clamps and landing gear parts make the model feel stout. The motors have clean little integrated mounts, and all the electronics came pre-wired. All the flyer is left to do is mount the propellers (with thread locking compound!) and landing gear, and install your own RC receiver. Any simple 4 channel airplane radio or better will work, helping keep the costs down, and without all the moving parts of a helicopter this quad should be fine with 72mHz control systems for flying through the trees (helicopters tend to create a lot of RF interference issues for 72mHz). The flight control system even offers integrated tilt and roll control for a camera mount, but there is no information at this time about how to implement this system.

After connecting the quad’s servo connectors to my receiver ( a Futaba FASST 2.4 gHz receiver), I followed the instructions for final setup, which involves nothing more than running the motors at low RPM and getting your servo reversing correct in your transmitter. Once this was done, I had nothing slowing me down from stepping outside and giving it a test flight.

When you first power up the T580, its important the model is sitting on level ground, and you don’t want to disturb it for a few seconds while it goes through its initialization process. The manual shows the model including a main power switch, which would help with keeping the model stable during initialization, but the final product I received has no such switch. Because of this, it can be a little tedious to get the model plugged in and powered up without disturbing it, but as long as you are aware, it’s not a big issue. Once the model has finished this process you are ready to fly.

3^rd Person View Flight Testing

Once the model is initialized, all it takes to bring it into a hover is to advance the throttle to about half stick. When you first bring the throttle up there is a delay; at first you only want to give it about ¼ throttle, once the rpm’s come up you can continue to ramp up the throttle. One thing novice flyers will have to be careful of is over-controlling the aircraft, especially during takeoff. You must keep in mind to only add inputs for where you desire the aircraft to go, trying to make corrections for every little movement will get you into trouble quick as you chase your inputs; just let the model do its thing and use small control inputs to guide the T580 where you want. It also helps to keep it close and not too high for 3^rd person flying, because with only a piece of yellow shrink tubing to distinguish the front from the rest of it, it can get to be hard to see very quickly.

Moving the T580 into forward flight, the model feels very solid, at slow speeds, but it gets to a point where it starts to act a little funny. While the T580 flies nice and predictable at slower speeds, it definitely has a limited flight envelope.

When you try to open it up for speed or fly it in turbulent or windy conditions, it starts to have trouble providing adequate control. Sometimes this results in the model not wanting to slow down or pitch back with your inputs when you start to get too fast, and sometimes the model flips over if you try to over correct and force it to recover, or if it encounters turbulence.

With no extra weight on board the T580’s built-in altitude hold feature seems to work fairly well. The manual describes that if you leave the throttle stick alone for 2 or more seconds, it will hold the altitude. I found the model has to be in a hover first, if you are climbing or descending when you leave the throttle stick alone, it will not hold its altitude.

FPV Equipment Used

I pulled the proven FPV equipment off my Mini Titan helicopter for the T580, which includes an OCSC 420 CCD camera, and a 100mw 1.28 gHz video transmitter powered by a little 3 cell 500mAh LiPo. At first I used a home-made dipole antenna, but I latter switched to a cloverleaf CP antenna for better performance through the trees. This simple, independently powered setup has more the ample range for parkflying, and I wanted to keep the model as light as practical. My T580 did not include any kind of camera mount, but had lots of unused 2mm and 2.5mm threaded holes I was able to use for my own simple fixed camera mount. My mount also provides room for the video battery and moves the main pack lower to help improve stability.

1^st person view flight testing:

I felt very comfortable flying the T580 in 1^st person view right out of the gate, as long as I didn’t let it get away from me. If you start to get into it and let it get going too fast, it can get to be a scary ride as it either continues to cruise without responding adequately, or you get an abrupt flip and flutter to the ground. Kept slow, it felt good and solid, and I’ve had lots of fun cruising through the trees in my new back yard. The response is smooth and predictable at slow speeds, allowing me to navigate around and under tree limbs without a problem. It did however, seem to fly worse the more weight I added. I only flew one flight with the GoPro on board, and I won’t be flying anymore. Although it had plenty of power to carry the GoPro, the model’s flight envelope became even more restricted and it wanted to venture off much more easily in forward flight. The more weight I added, the more the IMU seemed to drift and the worse the altitude hold feature worked.

Durability

Fortunately the model holds up well to some minor abuse. Like any helicopter, chopping the power ASAP if there is an incident will dramatically reduce the damage, and it took about half a dozen crashes before I broke a propeller. The landing gear support struts and the motor booms are both susceptible to cracking in crashes. Once you crack a boom the T580 needs major disassembly for repair. Although the clamp itself is simple, you have to pull off the main flight control board to get to the clamp, and you have to unsolder the motor on the broken boom from the ESC board. If you get unlucky enough to break the boom corresponding to the lower ESC board (a 50/50 chance) you are going to have a much harder time getting to the solder pads as the top and bottom ESC boards are soldered together. Overall the T580 is tough and parts fit well, but it’s a shame replacing a boom is so involved. If the motors had plugs going to the ESCs, replacing the booms would be a snap!

Suitability for FPV

Flying FPV with the quad is pretty easy once you understand the basic controls and the model’s limitations, but its limited flight envelope can be pretty scary if you need it to stop on a dime. I’m enjoying the T580 for jaunts around the backyard, but I don’t feel comfortable getting it very high, and I’m disappointed how poorly it flew with my GoPro onboard. If the fast flight characteristics and performance in the wind could be improved, along with connectors added to the motors to facilitate easier boom changes, this quad would be a hands down winner! As it stands the fact it’s “receiver ready” is the T580’s biggest selling point. Although the model does not require PC connection to get it flight ready, this feature would be a huge asset to let a modeler fine tune the model for his demands and possibly address some of the model’s shortcomings.

Pros

+ Receiver ready out of the box
+ Finished, professional look
+ Long flight times (I’m getting 12 safe minutes with my FPV gear)
+ Durable
+ Altitude hold feature works well with minimal payload

Cons

- No way to fine tune settings at this time
- Poor performance at speed and in the wind
- Has a tendency to flip over if the pilot over-controls
- Performance degrades significantly with payload

Further information about this product

• Manufacturer Website of LotusRC
  
• Lotus T580 Discussion Thread

A review by Aaron Shell

Specs (as built)

• Fuselage length: 1,310mm
• Wing Span: 1,788mm
• Ready to fly weight: 1,700 grams

Components used in airplane

• Batteries: 2- 2200 mAh 3s LiPo packs in parallel
• Motor: RCHotDeals 2814/8 1000kV outrunner
• Prop: APC 10x5E
• Speed Control: Suppo 50 amp
• Servos: GWS Naro on tail, Hitec HS-56 on ailerons
• Control Receiver: Futaba PCM 138 DP
• BEC: 5amp 5volt BEC dedicated for video, running through a power filter.
• Camera(s): 1. GoPro HD with onboard battery, and USB plug providing 5 volts from BEC provides front camera and audio. 2. CX-161 380 line camera for left/rear facing view. Flytron video switcher used to select between cameras.
• Video Transmitter: Black Widow A/V 600mw 2.4 ghz

Components used on ground

• Video Goggles: Hacked Trimersion goggles
• Video Receiver: Built-in Trimersion rx, or Black Widow A/V w/ 8dbi circularly polarized patch antenna.
• Ground Recorder: Aiptek DV5800
• Control Transmitter: Futaba 12 FG with digitally synthesized 72mHz module.

Build

The EPP FPV arrived in a sturdy cardboard box with no damage. Each part was individually wrapped in plastic, and the pieces practically fell together into an airplane as I piled them on my work table. There isn’t much left to do, and any modeler with some experience will likely take the manual as a suggestion and toss it in favor of his or her own preferences. I tried to stick to the manual as much as I could and follow its suggestions for the sake of this review, but I would have done several things different if I were to build it under different circumstances. The manual also has several glaring errors, such as having two entirely different center of gravity ranges indicated. If you read in the back of the manual it says to balance the model 45mm-55mm behind the leading edge of the wing. If you read in the beginning of the manual, it says 100mm-120mm.

Wings

The wings are cut (rather roughly I might add) out of bouncable EPP (Expanded Poly-Propylene), like the rest of the airplane. Two fiberglass spars give the wings their strength, and the ailerons are cut free with a thin layer of foam remaining to create a live hinge. The spars are square on the outside, and have a tubular hole intended to fit the two 6mm x 200mm solid fiberglass rods which serve as wing joiners. The wing is completely flat with no dihedral, so everything lines up straight, but the fit was not snug between the fiberglass rod and the wing spar. This small amount of play with such a short wing joiner could easily work itself back and forth with enough force to split the wing spars, so I wasn’t about to chance the wing center-section. I used Gorilla glue to glue the joiners into the spars, and join the wings together. Gorilla glue expands while curing, and was able to completely eliminate the small amount of “wing flapping syndrome” which appeared prior to gluing the halves together. There is no mention in the manual of how to join the wing halves other than “Connected two wings by wing bolt.” you can translate that how you wish, but I was not about to risk my model and gear, so I glued my wings together securely!

Servo mounting for the ailerons is simple enough with a pre-cut plywood plate which you glue to the surface of the wing over the pre-cut hole for the servo. I chose to use Hitec HS-56 servos because I had them on hand and they fit the cutouts perfectly! HobbyKing leaves it up to you to route your servo leads, which is easily accomplished by making a slit with your hobby knife and pushing the servo lead into the foam. Its not even necessary to cut a channel out for the wire; in fact with a deep enough slit the hole almost closes back up after you push the wire in!

Tail/Boom

A fiberglass tube serves as the tail boom, and fiberglass plates are cut to fit together for the servo mounts. The servo mounts and pushrod guides slide onto the boom and get glued on, and its suggested the servos can be located anywhere along the boom to adjust the center of gravity. My choice among 9 gram servos on my bench was down to a pair of GWS naro servos, so that’s what went on the tail! Plywood brackets get glued to the bottom of the horizontal stabilizer and glued to the boom. The vertical stabilizer is glued directly to the top of the horizontal stabilizer.

Most of my gripes about this airplane are related to the boom and tail. First of all, the boom does not extend far enough into the fuselage for adequate stiffness. It appears there is still room to extend the boom deeper into the fuselage without even intruding into the radio compartment. The servo and pushrod mounts function for their intended purpose, but they are very draggy, and are prone to breaking on even the softest landings on the softest surfaces. The vertical stabilizer is too flexible and I suspect it may be fluttering at higher power settings, and as built according to the manual, the control horns all end up on the wrong side of the hing line.

Fuselage

Actually, considering how big the fuselage is, I was slightly disappointed with the amount of space left for equipment. The fuselage sides are thick, no additional structure exists besides the foam, so it has to be thick to provide adequate strength. In fact the sides are both 20mm, and the width of the space in fuselage is 40mm, so there is literally just as much foam as there is room inside (width-wise, at least).  The result is a roomy fuselage, but much narrower and not as roomy as you might expect looking at the outside dimensions.  My full size Futaba PCM receiver was able to fit width-wise, but if you have any larger components, you’ll have to either carve out some foam or mount them on their side. Although they are still functional, the peg holes and plywood support plates for the rubber band pegs are not located accurately, which lends a bit of a drunken look to the already gangly airplane. The plywood support plates for the rubber band pegs were not adequately glued either, during assembly all of them popped loose and had to be re-glued.

Canopy / Camera Mount

HobbyKing has pre-cut the canopy free from the fuselage, and split the huge canopy into an upper and lower portion for FPV. Other than a picture in the manual showing basic placement of a setup with the upper portion of the canopy not in use, there are no details suggesting what type of equipment should be used or how it should be placed. There is room on the canopy to use practically any FPV equipment, although if you add an OSD to the canopy it would become quite cramped. I’m looking at the fuselage for adding an OSD later. With the canopy split from the factory, the builder is free to either set up the model to have the canopy top off like shown in the manual, or use the upper canopy portion as a hatch, as I chose to do. The canopy is cut at the factory with a hot knife, resulting in some loss of material. The result is the parts do not fit perfectly together. Because its difficult to sand or trim EPP, I ended up gluing a strip of a rubber band to one side of the fuselage to improve the canopy fit, and I’m still not thrilled with the results.

Magnets are pre-glued into the foam for both the upper-lower split, and the bottom of the canopy to fuselage attachment. The idea of using magnets is sound IF it holds the canopy securely, which these DO NOT! These magnets are neither strong enough to be secure, nor were they mounted straight enough to mate together flat. I was uncomfortable using the stock magnets to hold my canopy, so I pried them all out and used my own idea. In the back of my canopy two carbon rods are glued securely and slide into holes I drilled in the fuselage. In the front I glued a dowel peg into the foam to serve as an anchor point to screw into. I did the same for the top portion of the canopy. My GoPro is held in place with a velcro strap which goes through both the upper and lower portions of the canopy, and a rubber band which is held on a carbon rod just like the wings behind it. I selected a rear facing position out the side of the canopy that provided a view from the wing tip to the tail for my secondary camera.

FPV Setup

This airplane was built with whatever equipment I could find at arm’s length. I decided to pull out all of my 5 volt equipment for the EPP FPV and power all of it off a dedicated 5 volt, 5 amp BEC through a power filter. I am using a GoPro HD to record in HD on the model and output an analog video signal for the downlink. A FlyTron video switcher allows me to choose between the GoPro and the secondary CX-161 from my radio. Although getting on in years, my trusty 600mw 2.4 gHz video transmitter from BlackWidow A/V (circa 2005) provides a great video link and also takes 5 volts for power. On the ground I can fly with either a pair of hacked Trimersion goggles and their built-in 2.4 ghz video receiver, or I can plug any monitor into my Black Widow A/V receiver with an 8dbi circularly polarized patch antenna which was originally matched with the transmitter.

Motor selection

At first I had selected and even mounted a Mega in-runner motor. With a projected all up weight of 900-1200 grams according to the manual, my 16/15/7 1300 kV Mega would have provided only about 150-175 watts of power at the prop. But, I felt it would be sufficient because I’ve had great luck with this motor on other airframes. When the airplane was nearly complete I weighed it, at the time intending to use a single 3 cell 2200 mAh battery, and it came in very overweight at nearly 1,500 grams! It was immediately apparent the actual weight would be a bit much for my little Mega. In a last minute effort to get a suitable power system on the model in a hurry without breaking my budget, I opted to make a trip to our local internet hobby supplier here in Portland, Oregon; RCHotDeals.com. The motor is a generic outrunner 2814/8 rated at 1000 kV, with a Suppo 50 amp speed control matched to it. Using a 10×5 prop, I’m pulling 250 watts from 2- 3 cell 2200 mAh packs in parallel, and a basic calculation using the motor’s 81% efficiency rating gives me approximately 212 watts to the prop.

This combo has proven to be a decent performer for endurance. Doing some basic math, if I continue to fly with similar power demands as during my test flights, I can fly a safe 13 minutes. I flew for 9:40 and used 2600 mAh. I can use 3750mAh of the 4400mAh in my packs to leave a 15% buffer for safety and my pack’s longevity.  I was using 274 mAh/minute based on my flight time and what I put back in the packs after the flight, so by dividing the 3750mAh by 274 mAh/minute, I arrive at my 13.5 minute flight time. If I were to fly with a 3s 5,000 mAh pack, I still would only get about 15 minutes without pushing the safety buffer.

Flight Testing

When the model was complete, it seemed it would never stop raining! After waiting through the downpours for what seemed like months, I finally got a perfect day to fly. I chose to fly at a local park which allows RC flying, and provides a great view of the Willamette River and Mt. Hood in the distance.

Launch

With adequate power available, getting the EPP FPV airborne is easy. A firm toss gets the model moving at sufficient speed, and having the propeller mounted up high allows you to launch with the power on without worrying about your hand getting hit by the prop.

Cruise

This is where the EPP FPV shines! Its stable, gentle and easy on the controls. It takes a coordinated effort between the ailerons and rudder to fly smooth turns, I am not of fan of using aileron-rudder mixing. I found the turn may begin with rudder and aileron in the same direction, but shortly after achieving the desired bank angle I found myself feeding in some opposite aileron while holding the rudder to make smooth turns. Exiting the turn is done by first relaxing the rudder input, and then leveling the wings with the aileron. The power required to maintain a cruise was slightly more than I expected, with almost half throttle being necessary to prevent the model from descending.

Aerobatics

The EPP FPV is not intended for aerobatics. Although its be possible to perform practically any basic aerobatics with it, I do not intend to fly any high-G maneuvers because of the less than ideal wing center section. If you intend to fly high-G maneuvers and aerobatics with yours, you should consider replacing the wing joiners with a much more substantial length of real carbon-fiber tube. I had no problem rolling the model, but Boeing also rolled a 747, so it’s not saying much!

High Speed

Like aerobatic testing, I kept the high speed testing to a minimum because of fear of folding the wing, or ripping off the vertical stabilizer. The airplane does not pick up much speed at full throttle vs. cruise anyway, so trying to fly it fast is just going to waste power.

Slow Speed/Stall

Slow speed flight is stable, and if you do push it to the point of a stall it drops the nose straight down and does not have a tendency to enter a spin. You do need to keep up a fair amount of power to keep it in the air, and the model will sink rather rapidly without enough throttle.

Glide

Its stable, but sinks rather quickly. This airplane is not going to be winning any thermal competitions, but the benefit of this rapid sink rate is it’s easy to land. Unlike a sport plane with a fast sink rate which comes in hot, the EPP FPV is like having the brakes applied going downhill. It comes in slow and predictable making FPV landings easy. I did experience a strong tendency to yaw to the left upon chopping the power. I suspect the model may need a little left thrust to counteract a tendency to yaw to the right from torque. I’ve simply trimmed the model for a cruise setting with rudder, and the rudder is not needed in a glide. For now I’m just going to use a throttle to rudder mix to mask the problem, but I may play with adjusting the motor mount later.

Video

Control Authority

Despite the seemingly large control surfaces, I found the control authority nicely mannered and well suited for FPV. I tossed it around a little bit and was pleasantly rewarded with a smooth flying, easy to handle model that it a joy to bank around. I avoided pushing it too far for fear of the wing having issues, but its a joy to toss around. The rudder is very effective and it provides great maneuverability with the GoPro in a fixed position.  Placing the equipment low does seem to serve its purpose well providing some“pendulum effect” to the airplane, helping stabilize it.

Conclusion

HobbyKing’s EPP FPV is a good airplane offering great value. Most of the things I’ve mentioned could easily be improved during the build, but I wanted to stay true to the original design for this review. Most modelers will change or improve aspects of this airplane as they build and the result is likely to be fantastic! Beginners may get a little frustrated with the manual, so for this reason alone I would suggest this not be a first build. The weight being so far off from the manual really threw me for a loop picking a power system, but it worked out fine in the end. Although I do have a dual camera system with the GoPro, I don’t have any pan and tilt, an on-screen display, or a secondary battery for video, so I feel like my system is close to the average FPV system weight. The EPP FPV does not have a great speed range nor a ton of endurance, so I’m a little leery about using it for longer missions where it could encounter a headwind. Overall I’m happy with the airplane; the final result is I’ve got a great platform for my GoPro that is easy to fly, should be rugged ( I hope not to test this), and is easy to land.

Pros

+ Stable flight performance
+ Gentle stall characteristics
+ Easy to hand launch
+ Plenty of room for FPV components and batteries
+ Easy to modify to suit fliers needs

Cons

- Tail and servo mounting hardware is excessively draggy. Servos could easily be located in the tail surfaces with the leads running down the length of the boom.
- Canopy cut is very poor and the pre-installed magnets are not suitable.
- Support plates for wing dowels are located very inaccurately.
- Vertical stabilizer lacks stiffness
- Boom should be mounted further into the fuselage for more rigidity in the tail
- Wing joiners is a short length of solid fiberglass rod and does not fit snugly into wing spars.
- Wings are cut excessively rough, adding parasite drag.

Further information about this product

• Adding a  GoPro  to the EPP FPV- build log
• EPP FPV – Discussion thread
• EPP FPV – German review (follows)
• Heavily modified Hobbyking EPP FPV plane – build log

Technical data main module (manufacture data)

Type: extended version FY-21AP gyro 3-axes stabilization with RTH
Input voltage: 4.0 to 6.0V
Current draw: 52mA @ 5,0V
Size: 55× 33 x 20mm
Weight: 20g
Temperature range: -25°C – +70°C
Maximum rate of rotation: < 1200 °/s

Application: normal plane with and without aileron, v-tail with and without rudder, and planes with delta mix

Compatible remote control systems: Robbe-Futaba PPM / PCM 1024 / PCM G3 Mode Graupner JR PPM 8, PPM 12, SPCM Mode Multiplex PPM 8, PPM 12 with UNI Mode 1,5ms

Technical data GPS module (manufacture data)

GPS Data refresh rate: 10Hz
Interface features: TTL Level
Baud rate: 38000 baud
Data Bits: 8
Stop Bits: 1
Parity: None

Packaging and content

The package arrived well packed in an air cushion. The accessories were extensive. The module itself is about the same as the FY-20A, except for the 2 additional connections for the second switching channel and the GPS module. It is 55mm x 33mm x 20mm and weighs only 19g. Unlike many similar products, the module is not covered with heat shrink. The housing is robust and can be unscrewed.
With the circuit board removed it only weighs 9.5g.

Also included are five 18.5cm JR- servo connectors, one plastic shock mount, two pieces of Velcro tape and an illustrated English manual.

Functional principle and installation

Like the FY-20A, the FY-21AP offers, stabilization on three axes (elevator, rudder and ailerons). It’s even possible to control models with v-tail or delta mix. The model type is selected via plug contact. Three gyro sensors and a microprocessor provide the stabilization.

In contrast to the basic version FY-20A, the FY-21AP offers additional functions like RTH (return to home). This feature provides a semi-autonomous return to home function. For this the GPS module has to be connected to the FY-21AP main module. Flying circles with only the autopilot is also possible. So you can enjoy the landscape and let the autopilot do the work.

Unfortunately the system needs a y-cable for the second aileron. So it’s not possible to set an aileron differential via the transmitter. If the servos are running in the same direction, it’s possible to buy a y-cable with switchable inverting.
In the test we tried to misuse the rudder axes for the second aileron, but failed. Using only one aileron for stabilization made the RTH function too difficult.

The installation is done in a few steps. You should install it in a position with good airflow, to have a constant temperature. Otherwise the gyros will drift too much. The manufacturer suggests resetting the module before the flight if the temperature differential is above 30 °C. The same should be done after a longer break. Possible problems of the gyro drift are explained in the Flight Test chapter.
The FY-21AP calibrates itself after powering up. Once adjusted, you are ready to fly.
The module is mounted with Velcro tape onto the shock mount. The printed arrow on the module must be in the flight direction.

Flight modes

- Switch IN 1 – mode 1: Deactivated – normal RC control – no stabilization

- Switch IN 1 – mode 2: Auto balance mode – aircraft will enter horizontal level flight, when the transmitter’s control sticks are centred. Deflections are limited and the FY21-AP will not allow any acrobatic flights.

- Switch IN 1 – mode 3: Auto balance mode with fixed altitude – aircraft will enter horizontal level flight and stay at the current altitude, when the transmitter’s control sticks are centred. Deflections are limited and the FY21-AP will not allow any acrobatic flights. Attention: throttle position has to be set manually, because it won’t be controlled by the module. It is possible to set a fixed throttle position, but this can cause problems with non self stable air crafts. Especially if the down thrust is not correctly adjusted. You have to test this yourself how the plane reacts. Alternative you can use the Eagle Tree OSD Pro in combination with the FY-21AP. This OSD can control the throttle for the right level flight. For example to use the throttle channel separate with the OSD Pro without use of the rudder function of the OSD.

Autopilot modes

- Switch IN – mode 1: RTH (Return to home) – The model flies independent and stabilized back to the pilot. At arrival the model flies circles with a diameter of around 200 meters. Attention: throttle position has to be set manually, because it won’t be controlled by the module. Alternatively you can use the Eagle Tree OSD Pro in combination with the FY-21AP. This OSD can control the throttle for the right level flight. For example to use the throttle channel separate with the OSD Pro without use of the rudder function of the OSD.

- Switch IN 2 – mode 2: autopilot deactivated

- Switch IN 2 – mode 3: ACM (auto circling mode) – The model flies independent and stabilized circles with a diameter of around 200 meters. Circle position is position of activation, independent of the home position for RTH. Attention: throttle position has to be set manually, because it won’t be controlled by the module. Alternative you can use the Eagle Tree OSD Pro in combination with the FY-21AP. This OSD can control the throttle for the right level flight. For example to use the throttle channel separate with the OSD Pro without use of the rudder function of the OSD.

The modes are switchable during the flight. You will need two 3 position switches at the transmitter. If you have only a 2 position switch, you can only choose between mode 1 and 2 or between mode 1 and 3.
The ailerons are connected through a y-cable with the FY-21AP. Rudder and elevator are also directly connected to the module. We had no problems with the connections during our test. All plug connections were stable and their connections secure.

During the first start-up you have to check the correct rotation directions of the servos and the rudder effect in the stabilization mode. With the help of the three rotation potentiometers you can set the maximum deflections and the correct rotating direction. We suggest using as much as possible small deflections to get the right feeling during flying. Too big deflections can cause the loss of the model, if you are not fast enough to deactivate the stabilization during the flight.
Close Attention is required and the maxim “Less is more” is valid here.

Flight tests

Chapter 1 – stabilization

For the maiden flight we chose the Bormatec Maja. We did a test flight with and without the shock absorber during low and high wind conditions. We flew the Maja without stabilization to a secure flying level and switched to mode 2.   In this mode the FY-21AP fully controls the model. We watched amazed how stable the Maja was, even with its weight of around 3kg. Even stronger gusts of wind had no negative effects. This is one of the main advantages of this system. We could not control the Maja that accurately while the wind was blowing so much. There was no noticeable deviation in the flight path. The Maja flew stable and smooth.
Controlling during mode 2 is a little unfamiliar. It is like having 100% expo on all channels, but we quickly got used to it. The model was still very controllable and we felt secure knowing the FY-21AP would take over if we needed it to.

You need watch the flight speed during autonomous flight; especially with non-self-stable models, as it could result in a stall.
The FY-21AP does not like vibrations. That’s why the shock absorber is very important. We made test flights without this absorber and the FY-21AP reacted with uncontrolled deflections. Tests with gas driven aircrafts showed that the FY-21AP will work with reasonable damping of the module, like foam or cotton wool. During our longer tests in different weather situations we noticed a little drift because of temperature fluctuation. We could fix that really fast and easy with a manual calibration. That’s not a big problem and conforms to standards.

For comparison, The FY-21AP was tested in a Multiplex Cularis. Except for the much tighter fit, the system performed as described above. Only the fixed altitude mode worked, because the self-stableness of the Cularis is more precise.
The FY-21AP has consequently no problems with electro sailing planes or even motor planes.

Chapter 2 – ACM mode, autopilot and fixed altitude

ACM mode

ACM stands for: auto circling mode. We powered up our plane and waited until the FY21-AP gets its home position via satellite link. The led signals shows the actual state, which is described in the manual.  After that we did a short pre flight check and started the plane. As stated in the manual, the ACM mode centre is the actual model position where you activate the mode. We flew away with the plane and activated the ACM mode. Immediately the plane started a constant turn, sometimes a right, sometimes a left turn. The radius was about 120 meters. We noticed that the plane banked a little too much, because of the relatively tight circle. This can be a problem at slower speeds, where the plane looses altitude during the circles. Generally the ACM mode worked reliably and the model was never out of control.
As an important side note: You can take back the control of the model immediately and at anytime in any mode.

Autopilot – RTH mode

We started our model again and flew away, then activated the RTH mode. The autopilot initiated a turn immediately and the plane flew straight back to its home position. Upon arrival the FY21-AP switched automatically to the ACM mode and flew circles until we took back control. After this successful test we did the same with transmitter turned off. We programmed the fail-safe and tested it. As above the autopilot flew the plane without problems back home.

We would have liked the FY-21AP to control for flight altitude, but alas no. If you activate the RTH at a 600m altitude, the plane will come back and circle at 600m. So you would probably need binoculars to find your plane in the sky, if you lost the video signal. You have to find the right throttle position to hold the altitude in the RTH mode. Just manually switch on RTH and play with the throttle stick to find the right value.

Fixed altitude

This mode is to hold the plane at a fixed altitude. Our tests showed that this mode is only useful if the plane does not climb or sink very much during different throttle positions. The FY-21AP is not able to control the throttle so; too much push from the motor can override the deflections of the FY-21AP, which can cause problems.  A mechanical correction of the throttle is necessary. Unfortunately this is not possible with all planes, so a correction of angle can help here.

Conclusion

The FY-21AP is a much better solution compared to the basic version. With the optional OSD you can get a fully graphical flight system with auto pilot. The different functions do their jobs reliably. The small enervations do not diminish the use of this product.
Especially for the price of the FY-21AP, you get a very good package.

Scoring

Pro

+++ versatile additional functions compared to the basic version
+++ reliable operation
+++ very lightweight
+++ small size
+++ uncomplicated and easy assembling
+++ modes switch able during flight
++ extensive accessories inclusive

Con

— throttle is not controlled by autopilot
— no second aileron connection
– little gyro drift in the case of intense temperature fluctuation

Further information about this product

• FY21AP Review (German)
• FY21AP – Discussion and Support Thread
• FeiyuTech Homepage
  
• FY21AP Manual
• Antenna tracking with FY21AP (Video)
  
• MAJA as platform for FY21AP review (English)
• MAJA as platform for FY21AP review (German)

Following parts were delivered:

• 1x TXV582 5.8 GHz 200mw transmitter
• 1x R5800 5.8 GHz pocket size receiver
• 1x Transmitter’s power plug with leads
• 1x Receiver’s A/V out cable with RCA plugs
• 1x Power plug with lead for Rx
• 1x SMA converter for Rx
• 2x 3dBi whip antennas

A Review by Stefan B. aka BlueAngel

Technical Data of the main components (manufacture data)

Transmitter

• High grade switching regulator
• Built-in microphone with volume control
• Working voltage: DC 7-16 volts
• Camera output: 12 volts
• 8 Selectable channels: DIP switches
• Working frequencies: CH1:5705 – CH2:5685 – CH3:5665 – CH4:5645 – CH5:5885 – CH6:5905 – CH7:5925 – CH8:5945
• Current consumption: 180mAh
• Digital phase-locked loop circuit, no channel drift issues
• High quality noise filtering circuit
• Regulated output voltage for the camera
• Low profile circuit board
• All Molex type of lathed plugs for safe connections
• Dimensions:14 x 26 x 39 mm (0.45″ x 1″ x 1.5″ inches)
• Weight 26 grams (0.9 oz)

Receiver

• Dual (2x) A/V outputs.
• 8 Selectable channels: DIP switches
• Working frequencies: CH1: 5705 – CH2: 5685 – CH3: 5665 – CH4: 5645 – CH5: 5885 – CH6: 5905 – CH7: 5925 – CH8: 5945
• Working voltage: DC 9- 13 volts- Current consumption: 120mAh
• Dimensions: 13 x 52 x 60 mm (0.4″ x 2″ x 2.5″ inches)
• Weight 48 grams (1.7 oz)

Installation

The BEV 5,8GHz 200mW set is plug and play. Everything is provided to get a working system. You  only have to solder your own power plugs for the transmitter, receiver and the connections to the camera. The transmitter uses the same Molex connectors like the ImmersionRC products, but here you have to be careful. They don’t have the same pin layout and so you can easily fry your camera. I think the reason they choose this other layout is it allows the camera to be connected to the transmitter with a standard servo connector. The power plug of the receiver is very small. It worked well for me, but others have mentioned having problems. Maybe a bigger connector would solve this.

The transmitter came without protective heat shrink, so I suggest applying one to protect the other electronic components. You can cut holes for the microphone and the dip switches.

The transmitter and the receiver both have SMA-RP connectors. That’s quite different from the “standard” SMA connectors we normally use in FPV. One reason for this choice is the variety of wlan antennas on the market. I don’t like this because all of the main FPV manufactures use SMA and so are not compatible. The good thing is, that there is a SMA-RP to SMA adapter provided with the set, so you can use your own patch antenna without soldering a new connector on it.

On our test unit the power cable from the transmitter had the wrong polarity. The transmitter has a diode right after the input.  I don’t want to know what would have happened if I had plugged it in reversed. It was a fast and easy change, but better quality control is needed to eliminate this problem, especially because plug and play users will not generally notice these details.

Getting technical

Transmitter

The transmitter weighs exactly 25,1g and its 3dbi omni antenna 9,6g. So that’s 34,7g without heat shrink. It has an aluminium heat sink on top to provide good cooling for the transmitter. The transmitter uses a SKY-RF SKY-TX5823 RF module.

It is a 200mW module and operates normally at 3,3V. It delivers 22dbm (~158mW) at 3,3V and 23dbm (~200mW) at 3,4V. The regulator on the transmitter supplies the module with about 3,34V, so the real output is anywhere between 160 and 200mW.

The description of the transmitter claims a very good noise filtering circuit and a 12V output for the cam, so lets see how it really works.

There are many capacitors and a big coil on the board.  You can connect the TX directly to the main battery. I have tested currents up to 40A and have seen no degradation of the video.
The 12V output must be mistranslated, because there is no regulated 12V output for the cam. The cam gets the same voltage from the input minus a voltage drop of about 0,72V. This voltage drop is a result of two 1A Schottky diodes. Between them, there are 2 capacitors. This is the noise filtering for the cam and that’s not enough. Good noise filtering needs a classical LC-filter, but here we have only the capacitors. When I hit the throttle I can see a degradation of the video when the current rises above 10A in my set-up. This can vary in each set-up, but as stated above, a true LC-filter would have solved this problem. I suggest using a separate LC-filter for the camera.
The transmitter has a built in microphone. It is useable but not as good as a standard external microphone. Even with the volume at maximum it is a little quiet. The placement of a mic directly on a transmitter is also not the best choice, because most of the TX will be outside the plane and will pick up a lot of noise from the air. The transmitter has one mono audio input but if you’re using an external mic, you can turn off the internal one.

The transmitter works down to 4,8V when the video is no longer transmitted.  I don’t know if the output power will go downbefore cutting off, so 6V should be a secure minimum voltage.

I tested to see how much current the TX needs and how hot it gets. The room temperature was 23,0° the TX was laid on the table with the heat sink on the top and without heat shrink.

After 30 minutes the temperature and current do not change. All values are within the specifications (70°C) and there were no problems.

Receiver

The receivers weight is 43,9g and is pretty small, only 62x53x14mm.

The receiver uses a Sky-RF Sky-RX5808 RF module. It is a very sensitive module which works from 3,5V to 5,5V at -90dBm. The receiver uses a standard 7805 voltage regulator to power the module, so it should work to a minimum of 6V.  The test showed that it works down to 4,3V then the video does cut off. The receiver has two separate video and audio outputs so a video splitter is unnecessary. You can connect your goggles and recorder without the need for an additional device.The receiver needs approximately 2,5W, that means about 250mA at 10V.

It gets only slightly warm and, like the transmitter, showed no temperature problems. The audio output is on two channels, that means the mono audio is mixed to both. This has the advantage of hearing the audio in both ears of the video goggles. The SKY-RF modules are transmitting on 8 different channels in the 5,8GHz band. These channels are not compatible with the ones from Airwave.

Flight test

I was using my Robbe Arcus electrical sailing plane equipped with the Simple OSD  XL for this test.   This way I was able to use the GPS data for analysis.

I made 3 videos:

1. Ground test
2. Flight test with TX on the upper side of the fuselage and antenna pointing up
3. Flight test with TX on the side of the fuselage and antenna pointing down

1. Ground test:
The receiver was on top of my ground station at a height of about 1,90m. The antenna had a clear 360° view. My assistant took the plane on his bike and drove down the road.

We reached about 1025m, after that the picture got worse and cut in and out. That is quite good with only the two 3dbi omni antennas.

2. Flight test:
I mounted the transmitter on the top of the fuselage with the antenna pointing up.

I flew to a maximum distance of 900m. While returning the video cut in and out a lot. I believe this is caused by the cam or the electronics blocking the signal from the antenna. This is why I made a video with the antenna pointing down.

3. Flight test 2:
I mounted the transmitter on the side of the fuselage with the antenna pointing down so there was nothing blocking the line of sight of the antenna.

You can see the improvement with the different antenna placement. I flew to distance of 1020m and had good picture most of the time. I could have gone a little further, but my RC-range was at its limit.

Conclusion

The BEVRC 5,8GHz 200mW Plug and Play system does its job very well. I have already made many flights with this system and have used a 7dbi patch too. 1200m flights were no problem, but I’ve had to turn back because my 2,4GHz Frsky system’s failsafe kicked in.

To compare these results, I flew my 5,8GHz 25mW Airwave system to 1000m with perfect picture and a 18dbi patch. With the stock 3dbi antennas I only get 200m. You can get really incredible range with the BEVRC 5,8GHz system when using a patch antenna.  The issues with longer ranges have nothing to do with the BEVRC system but with the 5,8GHz frequency.

Polarisation-, Multipath- and Signal blocking-problems have more effects. You can see this when you compare the videos of flight test 1 and 2.  At close range (about 400m) the effects are minimal  so fun relaxing flying is no problem.  You can see this in the Simple OSD XL Test.

Score

Pro

+++ very good range with stock antennas – 1000m
+++ very sensitive receiver
++ dual output A/V
+ small system

Con

- SMA-RP connection
- Microphone too quiet
- Cam voltage filter could be better
- Attention about the connections on the transmitter

Result

Further information about this product

• BEV 5.8GHz 200mW FPV System – Discussion Thread
  

A Review by Aaron Shell

Packing and Contents

Packaging was a little scarce. At first I was afraid the camera may have incurred damage during shipment; the box was sent in a regular envelope, and it was smashed. Fortunately the camera wasn’t damaged en route. Included with the cam was a connector with a length of wire lead, and a basic spec sheet. After a quick visual inspection of the camera and reading through the note on hookup, I was ready to proceed with putting this camera into action.

Technical Data/Specs

• Resolution: 420 TV lines of resolution, 512(H) x492(V) total pixels
• Sensor: 1/3 inch color CCD sensor
• Minimum Illumination: 0.4 Lux @ F2.0
• Signal to Noise Ratio:  more than 48dB (AGC off)
• Gamma correction: 0.45
• Power Source: 12 volt/ 3s LiPo
• Lens: f3.6mm /F2.0 92°
• IRIS Mode: Automatic Electronic Shutter (AES)
• Gain Control: Auto (AGC)
• White Balance: Auto
• Video Output: 1.0Vp-p Composite, 75ohms
• Dimension(mm) 36 x 35 x 30
• Weight: 16g

Setup

According to the note included with the camera, the red wire on the harness was 12 volt positive, the white is video, and the rest get grounded. I had it hooked up in short order to my 400 mW 1.28 gHz video transmitter, which also works off 12 volts. A simple harness powers both the camera and video transmitter from a 3s  800 mAh LiPo dedicated to video. Having a separate battery for video helps mitigate any interference from other on-board electronics. I built a simple fixed camera mount with a few scraps of G10 fiberglass board, and affixed it to the airframe with hot glue. You’ll have to get creative for your mounting solution, there are no suggestion for how to mount the camera.

There is a pin on the right side of the case, and a threaded hole opposite on the left that could be used for tilt, but you are on your own to figure out how to use them. My FPV platform for this test is my Thunder Tiger Mini Titan 325 SE helicopter, with some extras like a raised tail from the Super Cobra scale conversion kit to help with FPV heli landings.

Once installed, a simple threaded adjustment on the lens like most CCD cameras allows you to adjust focus. I usually pick an object at a distance and try to focus, then check something near and make sure its a good balance. A simple spring is all that keeps the focus setting; it may not be a bad idea to add a dab of hot glue to prevent bumping it once you find a setting you are happy with.

Picture quality

While not HD quality, I found the picture produced from the OSCS420 to be more than adequate for FPV flying. The picture showed greens and darker hues well, and images of the ground show excellent clarity, but it seemed to wash out looking into the bright blue sky. Although it does this, the image did not do anything funny to the rest of the picture like the CX-161 is known to do, it just doesn’t show the sky in all its glory. In my video during the day the sky was actually clear and bright blue, but the image appears as if the sky was overcast. Although the picture was not perfect at those times, the image was still more than usable for flying while looking into the sun.

Comparison Day/Night

I tested the camera at night during a full moon, and even with this much illumination, I relied heavily on street lights and other city lights to determine my attitude. Virtually none of the ground visible to the naked eye under the moonlight showed up on video. In my experience, this makes the camera suitable for night flying only when there are enough artificial lights to rely on. Having just a moonlit background won’t provide enough contrast to produce a usable image. With that being said, the camera does work well for night flying as long as you have street lights or something for reference.

Flight Test

Any time you commit your FPV aircraft to the air with a new component on board, it can be a bit nerve wracking. With the OSCS420 camera, I was happy to feel right at home with the viewing angle and the image it was producing. Almost right away I could tell the camera was not showing the vivid blue of the sky, but the depth of clarity on the ground was impressive.

Using a heli for a test platform really puts the camera through the wringer with more motion and vibration than  a fixed wing. I never had any issues getting the OSCS420 to cooperate, and I’m very happy with the detail it produces on the ground. I appreciate this ability immensely with the heli, it has proven to be quite an asset for low hovering and landing.

Conclusion

The OSCS420 camera is a good compromise for a lightweight CCD FPV camera. Its got excellent performance across a wide range of conditions, considering it doesn’t have any manual adjustments. I was a little unimpressed with this camera for night, it works okay, and it can be used for night flying, but its nothing like a super low lux black and white cam. This camera could be the heart of a great FPV setup, but its really up to the modeler for how to mount the camera, and that could lead to a poor image if fliers have a less than ideal mounting solution. It appears there is a location on the board for a microphone, and my guess would be if you add it there is a way to make it work, but I have no idea if this is practical or even possible. I would like to see a version of this camera with a complete mounting solution for either fixed or pan and tilt, and a microphone added to the board, if possible.

If the camera was a more plug and play solution for the average modeler, or even if the company offered a mounting kit, this camera would be ideal for most FPV fliers. I’m giving it a lower score not because it lacks in performance, but because it does not offer any mounting solutions, and with the back exposed, its a little awkward.

Pros

+ Great clarity on the ground
+ Light weight
+ Works well as a Day/Night cam
+ Good viewing angle for FPV flying

Cons

- No mounting solution
- Large frontal area
- Night performance requires artificial lights for reference

Result: good up to satisfactorily

Further information about this product

• OSCS420 Review – German
  
• OSCS420 Discussion Thread – English
• OSCS420 Discussion Thread – German

Cable duct

The new wing has a continuous cable duct. It is 40mm wide and 15mm deep. With the new version, it is easy to fit all the cables inside the wings. Cutting is now no longer necessary. There is enough room for external sensors or lighting systems.

Internal wing spar

Compared to the old version, wing spars cannot be seen from outside. They are now rotated 45 degrees, thus rhombic assembled inside the wing. This improves the stability of the wing and is noticeable during the assembly. The main disadvantage is that the spars are not easy to change like in the old version. However, the Maja is a tough plane and it takes a lot of force to bend the spars.

Wing fastening

Eariler in the MAJA test, we criticized the insecure wing locks.
The manufacturer has made a big improvement. The locking system is now the same as the fuselage; using Duro/Coroplast material. This method has proven reliable in many conditions thus there is no concern about loosing the wings in the air.

New wing profile

The Maja has a new wing profile. It’s a modified NACA 2412, which should improve the slow flight characteristics. The difference between the old and new wing profile can be only seen if you look very closely.
To feel the difference, we did a few test flights with the old and the new wings. Flying weight was brought up to exactly 3kg. We analyzed the flight characteristics of both sets of wings at a constant throttle of about ¾.
The resulting flight time was ~18 minutes with the old set and ~15 minutes with the new wings, neither times include gliding time. The lowest flight speed before stall was 25km/h for the old and 17km/h for the new version. Under 30km/h the old version was harder to control compared to 22-25km/h for the new wing design. We compared each wing on a second flight to confirm the results.
The tests showed a noticeable improvement in slow flying characteristics, which results in a slight decrease in flight time. This decrease in time will be barely noticeable under normal conditions.  Our tests were done under extreme conditions.
The results can vary with different power.

Our setup was the same as in the first part of this test:

Motor: Himax 3516- 1130
ESC: Simprop Magic Speed 42
Lipo: 2x 3s – 2450mAh parallel
Prop.: 10×6 Aeronaut Cam Carbon

Gliding and overall performance

The gliding performance of the Maja has improved with the new wings. The model does not loose height as fast as before. The landing approach is now a little easier. In sum the increase of gliding performance is the result of the better slow flying characteristics.

Conclusion

The new are an improvement and sport new features. The minimal decrease in flight time is only barely noticeable during normal flying.  This is because of the increase in gliding performance. The new wing has better stability and the new wing locks perform well even in rough conditions.
The company Bormatec continuously improves their models and upgrades as it goes.

Scoring

Pro

++ improved slow flying characteristics
++ improved stability of the wings
+++ new wing fastening
+++ continuous cable duct

Contra

– small decrease in flight time
– change of aluminium spars is more difficult

Result: good

Further information about this product

• Bormatec MAJA review – English
• Bormatec MAJA new wing review – German
  
• Bormatec MAJA review – German
• Bormatec MAJA discussion thread – English
  
• Bormatec MAJA discussion thread – German

We’ve just finished a new camera review. The review prodcut was the new OSCS420 night camera. The review will be published soon. Stay tuned.

We received the following parts for review:

• 1x Simple OSD XL
• 1x GPS 10Hz
• 1x Current sensor 50A
• 1x USB program adapter
• 1x small parts like connectors,…

Technical Data of the main components (manufacture data)

Simple OSD XL

• weight only 2.99g
• 27x35mm stamp size
• monitoring 2 batteries voltage and capacity and current(with optional current sensor)
• Plug and Play interface for easy usage
• Internal Audio Telemetry Modem for transferring values to the ground
• PC Based Audio Telemetry Modem software for receiving values
• PC Based Configuration Tool for Custom screen designs
• Alarm options for distance, battery and altitude
• Audible Variometer
• Record system for Max Speed, Altitude, Distance values
• 32kb code space for complex applications and useful screen
• IR port for Infra-red Dogfight and menu control with TV remote
• Optional 10hz GPS module with -163dB high sensitive active antenna
• Second battery monitor
• RSSI input pin for signal level monitoring
• Optional analogue pin for different sensors and Sensor design system
• EXT port for remote controls, digital outputs or IR gun for dogfight
• Firmware update system over internet
• SimpleOSD XL Web Manual

10Hz GPS module v2

• MediaTek Single Chip
• 16x16x6mm
• Patch Antenna: 15x15x4mm
• L1 Frequency, C/A code, 66 channels
• Embedded LNA and SAW filter
• With Active patch antenna
• High Sensitivity Up to -163 dBm tracking, superior urban performances
• Position Accuracy < 3m CEP (50%) without SA (horizontal)
• Cold Start is Under 35 seconds (Typical)
• Warm Start is Under 34 seconds (Typical)
• Hot Start is Under 1 second (Typical)
• Low Power Consumption 48mA @ acquisition, 37mA @ tracking
• Low shut-down current consumption 15uA, typical
• DGPS(WAAS, EGNOS, MSAS) support (optional by firmware)
• Max. Update Rate: up to 10Hz
• UART Interface
• Support AGPS function (Offline mode : EPO valid up to 14 days)
• 1 week backup time with Super Capacitor

The technical data is from the new GPS version 2. The difference is easy noticeable because of the backup battery. In the test I will use the old version 1 GPS.

50A Current sensor

• High quality 50 Ampere current sensor for SimpleOSD

USB program adapter

• Silab’s CP2102 based high quality USB to RS232 converter with 120cm long cable
• Full compatible with SimpleOSD Firmware loader software

This part is coming free with a new SimpleOSD XL(or Ultralight).

Installation

Contrary to its name, the Simple OSD is not a Plug & Play system. You have to study the web manual located at the manufacture’s website. A printed manual is not shipped with the unit. Special attention is needed for the power supply setup. Failure here can result in the destruction of your FPV equipment really fast. Even the wiring diagram in the web manual is difficult to follow for this.

The OSD needs a voltage from 7 to 24V. Normally its supplied by the current sensor. The current sensor directs the voltage of the connected battery (mostly the main flying pack) directly to the OSD. But this exact voltage is also directed to the connections for TX and cam (also to the connection of the receivers input). The wiring diagram shows, a 4s lipo, connected to a 12V TX and a 12V cam.  Not a good idea if you value your gear. Because of the direct connection of the voltage from the flight pack, you should use a filter to suppress noise.  So you can save the extra battery for the video equipment. If you want to use 5V equipment, a special 5V voltage regulator is necessary.

The OSD itself does not need any noise filtering. Even with the running motor, the display values do not flicker nor are there any other similar problems. The biggest difference between the Simple OSD and all the other OSDs out there, is the video and audio lines are not guided through the OSD, rather they are connected in parallel to the OSD. This is a big advantage, because in the event of OSD failure, there is still video and audio transmitted to the ground.

There are 2 ways to built up the OSD:

1) soldering plug connectors to make everything pluggable

• flexible construction
• GPS can be mounted on a different place for better reception

2) direct soldering the cables and the GPS module onto the main board

• compact construction
• less possibility of failures due to loose connections

Since version of the OSD already had soldered plug connectors (normal delivery with unsoldered pins), I decided to try the flexible construction. This type of construction needs much more space and the connections were to insecure. I suggest using a drop of hot glue or somthing similar to secure them.

Because of the planned use of the OSD in my FPV-Pod, I built it up once again. This time I soldered the GPS and the cables directly to the main board.  The small board leaves little room for big connections.

You have to solder your own battery connectors onto your current sensor. Soldering the XT60 directly onto the board was difficult. I didn’t want to risk a loose connection with so many plugs, so I decided to use cables. Unfortunately you can see the disadvantage of this solution in the picture. It’s big. Generally I wished the current sensor were smaller, because as it is,  the advantages of a small OSD are negated. There are current sensors available from the same manufacturer which are much smaller.

After finishing all the soldering and testing it, the main installation was finished.

Firmware

Principally everything should work smoothly here, like the “Simple” name indicates. Connect the USB adapter to the computer and install the drivers – start the software update – enter firmware code – update. Unfortunately there is when the “Simple” ran out.

The updated software displayed a finished update, but the OSD did not know that. Even disconnecting during the update, does not effect the updating process of the software. The problem in this case is the kind of update. The firmware will be written into the OSD without error check or verification after update. This often results in a corrupt firmware. So the OSD wont start any more. After many tries, different computers with different operating systems, I ended up having to use an older firmware in the OSD. After that was installed, I could upgrade to the newest one. The manufacturer has already promised to solve this problem with a future firmware update.

PC configuration

After updating to the newest firmware, its time to configure the OSD with the PC software. Connect USB adapter – power up the OSD – change your settings. The user interface is self-explanatory so you can quickly customize the settings. Nevertheless a better manual would have been great. But the configuration possibilities are limited, to stay with the “Simple” theme. There is only one line to change in the upper border of the display, therefore there are 5 different pages to set. You can use the switch on the board or the external receiver input.

You will need a continuous slider or pot. on the transmitter to switch through all 5 pages. With a 3 way switch only pages 1,3 and 5 useable. Additionally you can configure the standard alarms for voltage and distance, etc. The calibration of the current sensor is also very important. A first test showed a tolerance up to 30%. The best time to do the calibration is immediately after everything is put together. I managed to calibrate the voltage but failed to do the same with the current. Changing the calibration values does not have much effect.

Important features

The Simple OSD XL offers additional useful features.

1. RSSI: some RC-receivers provide a RSSI signal, which we could connect to the OSD. So the OSD can display the signal strength of the receiver, which is very useful. For example, we can turn back home before loosing control. The RSSI signal should be direct connected with a 10kOhm resistor in series to the OSD. I recommend to use a RSSI Buffer to prevent possible interference back to the receiver.
2. second current sensor: The OSD has a second current sensor input. So we used it to monitor a additional video battery. It’s possible to show the consumed mAh even on the second sensor input.
3. Infra-red port: This port should be used for IR dogfights or for configuration by a remote control. At the moment there is no use for it, so we’ll have to wait for future updates.
4. Internal Audio Telemetry Modem: The OSD has an inbuilt audio telemetry modem, to send data to the ground via the audio channel; values from the GPS or voltage for example, etc. On the ground the audio output of the video receiver is connected to the line in the computer. The software analyzes the audio stream and displays the data.  Live tracking with Google Earth is possible. In the future this data could be used for an antenna tracker on the ground.

Flight test

I assembled the Simple OSD XL onto an FPV-Pod. This helped make a fast change between two different planes.

The OSD starts very fast, after the battery is plugged into the current sensor. Because of the black back ground, the data is easy to read. The GPS acquires signal very fast, but you have to set the homepoint yourself. You have to wait until the GPS altitude stays at the same level and then press the button on the OSD, this resets all values to zero and sets the homepoint. Unfortunately this was not described in the manual and so took more time to figure out.

Here is the flying video with my Freescale X-Free 3D flyer:

Conclusion

The OSD does what it promises, but there were some difficulties. The name “Simple” is a little misleading because this is definitely not a Plug and Play system. Flytron has tried to keep everything “Simple”, but based on the variety of features this was not possible. There need to be some changes in the firmware and software to for this to be a “SimpleOSD”. The value for money is still good, but has competition from the new CEOSD. The SimpleOSD still enjoys market dominance.  It is the ideal OSD for people who want specific data displayed without distracting from the view. Indeed there are other OSDs, like the Eagle Tree OSD, which also configure to a simple display, but they are a lot more expensive.

Score

Pro

+++ very small OSD

+++ simple presentment of the information

+++ parallel connected to the video and audio cables

++ many functions

+ future enhancements (antenna tracker, IR-dogfight,…)

Con

— no Plug & Play system

— problems with the firmware update

— problems with current sensor configuration (30% difference)

– incomplete manual

- not everything is that „Simple“

Result: good up to satisfactorily

Further information about this product

• SimpleOSD XL review – German
  
• SimpleOSD discussion thread – English
• SimpleOSD discussion thread – German
  
• Web-Manual SimpleOSD XL Edition

Technical data (manufacture data)

Type: basic version FY-20A gyro 3- axes stabilization

Input voltage: 4.0 to 6.0V
Current draw: 5 mA (5V)
Size: 55× 33 x 20mm
Weight: 20g
Temperature range: -25°C – +70°C
Maximum rate of rotation: < 1200 °/s

Application: normal plane with or without aileron, with v-tail or standard rudders, and planes with delta mix

Compatible remote control systems: Robbe-Futaba PPM / PCM 1024 / PCM G3 Mode Graupner JR PPM 8, PPM 12, SPCM Mode Multiplex PPM 8, PPM 12 with UNI Mode 1,5ms

Packaging and content

The package arrived well packed in an air cushion bag delivered by DHL. The accessories were extensive. The module itself is in a light blue transparent housing. Its size is 55mm x 33mm x 20mm and weighing only 19g. Contrary to many similar products this module is not covered with simple heat shrink. The housing is robust and can be unscrewed.
If you want to save weight, you can take out the circuit board; it’s only 9,5g.
In addition the unit comes with four JR- servo connectors with 18,5cm length cord, one plastic shock mount, two Velcro tapes and an illustrated English manual.

Functional principle and installation

The FY-20A offers stabilization on three axes (elevator, rudder, aileron). It’s even possible to control models with v-tail or delta mix. The model type is selected via plug contact. The stabilization is provided by three gyro sensors and processor controlled electronics.

Schematic picture of the function:

Unfortunately the system needs a y-cable for the second aileron. So it’s not possible to set an aileron differential via the transmitter. If the servos are running in the same direction, it’s possible to buy an electrical y-cable with switch able inverting. In the test we tried to misuse the rudder axes for the second aileron, but failed.

The installation is done in a few steps. You should install it in a position with good airflow, to have a constant temperature. Otherwise the gyros will drift too much. The manufacturer suggests resetting the module before the flight, if the temperature fluctuates more than 30 °C. The same should be done after a longer break. Possible problems with the gyro drift are explained in the flight test chapter.

The FY-20A calibrates itself after powering up. Once adjusted, there are no additional steps necessary before flying.
The module is mounted with Velcro tape onto the shock mount. The printed arrow on the module must point in the flight direction.
The FY-20A must be connected with the following channels from the receiver: aileron, elevator, rudder and a free switch channel. Here we use the four servo cables provided. The switch channel is a user defined switch of the transmitter, like a three position switch. It’s used to toggle the three different modes:

• Mode 1: Deactivated – normal RC control – no stabilization
• Mode 2: 3D-Mode – stabilization with automatically recognizing the latest position of the aircraft – control deflection is unlimited
• Mode 3: Auto balance mode – aircraft will enter horizontal level flight, when the transmitter’s control sticks are centred. Deflections are limited and the FY20-A will not allow any acrobatic flights.

The modes can be switched in flight if desired. You will need a 3 position switch on your transmitter. If you have only a 2 position switch, you can only choose between mode 1 and 2 or between mode 1 and 3.

The ailerons are connected through a y-cable to the unit. Rudder and elevator are also directly connected to the module. We had no problems with the connections during our test. All plug connections were stable and the connections were secure.
During the first start-up you have to check for the correct rotation directions of the servos and the rudder effect in the stabilization mode. With the help of the three rotation potentiometers you can set the maximum deflections and the correct rotating direction. We suggest using as little deflection as possible to get the right feeling during flying. Too much deflection can cause a crash, if you are not fast enough to deactivate the stabilization during the flight.
Ultimate Attention is required and the maxim “Less is more” is valid here.

Flight tests

For the maiden flight we chose the Bormatec MAJA. We did a test flight with and without the shock absorber during low wind conditions. We flew the MAJA without stabilization to a secure flying level and switched to mode 3. At this point the FY-20A fully controlled the plane. We were amazed how stable the MAJA was, even with its weight of around 3kg. Even stronger gusts of wind had no negative effects. This is one of the main advantages of this system. We couldn’t control the MAJA as well as the FY-20A in those wind conditions. There was no flight path deviation noticeable. The MAJA flew stable and smooth.
Controlling while on mode 3 took some getting used to. It is like having 100% expo on all channels, we adjusted quickly. The model was responded very well and the flight felt very secure.  You should watch the flying speed during an autonomous gliding flight, especially with non self stable models, because of the risk of stalling.
In mode 2 (3D-mode) the control effects are neutral and you can fly as normal. The FY-20A in mode 2 worked like a head holding controller. The FY-20A tried to maintain the plane’s position every time we released the control sticks. Our aircraft and settings were certainly not the set up for 3D flight. To do this would require fine-tuning of the deflection values. Basically the 3D-mode works as it should and is perfectly suited to the ambitious 3D flyer.

The FY-20A does not like vibrations. That’s why the shock absorber is very important. We made several test flights without this absorber and the FY-20A reacts irraticly. For this reason the FY-20A would not work well in a gas driven aircraft, though due to missing models we were unable to confirm this.  During tests was the weather quite hot, and we noticed a little drift because of the temperature fluctuation. We could fix that really fast and easy with a manual calibration.

For better exemplification we show you a flight video:

Conclusion

Compared to its competitors, the FY-20A is a small and lightweight device with well thought out engineering. The price of about 110 Dollar makes it affordable and attractive. The only thing missing was the second aileron connection. The stabilization system works very well and does make flying safer. The shaking so common in video and photographs is reduced and approaches for landing are easier. Flying in higher wind and even complicated 3D flying figures is easy, even for the untrained pilot. The system is not suited for the absolute beginner. An experienced pilot should help during assembling and configuration to avoid crashes.

Scoring

Pro
+++ reliable operation
+++ very lightweight
+++ small size
+++ uncomplicated and easy assembling
+++ modes switch able during flight
++ extensive accessories inclusive

Con
- – - no second aileron connection
- - little gyro drift in the case of intense temperature fluctuation
- manual only in English and sometimes mistakable

Further information about this product

• FY20A discussion thread – English
  
• FY20A discussion thread – German
  
• FY20A Review – German
  
• FY20A manual (last updated 29th July 2010)

We will test the flight characteristics with this new wing.
The experiences with the new wing will be added to the current MAJA review.