Easy Star + Ailerons + FMA Co-Pilot = Awesome!

F0r some time now I have been taking aerial photography and video from my Easy Star. With the brushless upgrade, the plane can easily carry 5 - 7 oz of extra payload. One problem is keeping the plane nice and level for good video and photos. To solve this problem I have been eying the FMA CPD4 Co-Pilot. For around $70 you get an infrared sensor which distinguishes the temperature difference between the sky and land, and controls the ailerons and elevator accordingly to hold the model level. Being a sucker for gadgets I decided to give it a try.

Though I have read other posts from people who used the CPD4 with elevator/rudder only, I wanted to use ailerons for better stability. I followed the lead of Ian from rcgroups.com who very thoroughly documented the process of adding ailerons. I used Hitec HS55s for servos and standard park flyer control rod hardware. I adjusted the aileron size and location a bit. I cut them 12 inches long and 2.5 inches deep starting 6.5 inches from the wing root.

The Easy Star's upturned wingtips are designed to keep the plane level which means the plane will fight you a bit when trying to turn with ailerons. In the above mentioned post Ian flattened the tips; but for this application I want the plane to be as stable as possible. For regular flying with the CPD4 off, I mixed in some rudder with the ailerons on my TX. This makes the turns nice and smooth and in my opinion better than with the stock rudder only setup.


With the ailerons working well I began installing the Co-Pilot. The directions are very thorough which is a real plus. As far as physical setup, the biggest decision is where to place the CPD4 sensor. The weight is not the issue and would have no noticeable effect on the center of gravity
(CG). The sensor needs a clear view of the sky in 4 directions. The traditional setup is on the wing or bottom of the fuselage, but the design of the Easy Star does not lend itself to this setup. I followed the procedure for the special application setup which calls for mounting the sensor diagonally and switching the position of the number 3 switch on the Co-Pilot. After some thought I decided to mount the sensor on the tail boom. Partially to get it out of the way and partially to use up the long cable that came with the kit. I mounted the sensor with velcro which seemed to work fine. The Co-Pilot computer tucks nicely up in the nose of the aircraft and velcros easily to one side. Following the instructions I plugged the copilot into the receiver and servos and went through the initial setup procedure. I would highly recommend plugging the remote into a spare proportional channel on your TX/RX if you have one. This allows you remotely control the sensitivity (gain) of the co-pilot.

Flight Report:

The instructions include a pre-flight checklist which I highly recommend adding to your regular checklist. There are several unfamiliar steps that you don't want to miss. Before every flight you need to calibrate the co-pilot to adjust it for your flying site/weather conditions. Based on the calibration you get feed back on how good the conditions are for the co-pilot--on this particular day I got a 5 out of 10 which seemed to work just fine. Even before take-off I was immediately impressed to see the co-pilot correct any movement away from center. All the control surfaces were perfectly reacting to return the plane to level.

Thinking in my head this must be too good to be true...I decided it was time to take off. For take off I turned the co-pilot off using the dial on my transmitter. After I was several mistakes high, I turned it up to full..and instantly the plane leveled out. It still couldn't believe it so I put it to the test and began a series of turns using only the rudder. Just as you would expect, the Easy Star made nice (wide) flat turns with the co-pilot providing the appropriate input with the ailerons to keep the plane level. To have a little fun with the system I turned it off and put the plane into a steep spiral dive. As soon as I turned on the co-pilot the plane almost instantly returned to level. Even with the co-pilot on you can still use the ailerons and elevator, just be prepared to provide alot of input to override the system. The co-pilot really shines during landing. I chopped the throttle and used the rudder to line up the plane. The co-pilot holds the plane perfectly level as you come in for a landing, all you have to do is a little flare at the end!

Final Thoughts:

Flying over water, ice or valleys can reportedly cause some problems for the system. The site I fly at borders the SF Bay which is definitely a large, cold body of water. I took the plane over the Bay a few hundred feet or so and did not notice any degradation in performance. As far at the co-pilot goes, it is great for aerial photography/video as the plane is level for good shots and you have the freedom to put more thought into taking pictures rather than flying. The co-pilot is not a replacement for good flying skills, and though it could be used to help a beginner, I think you are better off learning using a buddy-box or simulator. Alternativly you could go the route I chose which is a really tough plane (easy star) and plenty of glue ;) That said, the FMA Co-Pilot is a nice to have extra and worth every penny!