|This is the Sig Fokker D-VII biplane. Here is a pictorial review of the Modification I made to the plane.|
|carbon fiber to the elevator.|
|Stained the struts.
CF to the lower wing.
FLex Comparison to stock wing.
|Repainting, and detailing.|
|Brushless motor, cowl screens, magnetic engiine cover latch.|
fiberglass reinforcement to LG.
Home-made prop saver. Added later.
|It is done!|
|Fokker RE-MAIDEN flight report:
First let me review the changes -1. Removed some right thrust, added a touch more down thrust, 2. Adjusted the zero point of the elevator servo. 3. Added a home made prop saver. I picked a perfect morning-sunrise with 3 mph winds. No runway so hand launch and ditch to land. After the check of the control surfaces and range check I toss it aloft. It climbs quickly-- less severely than before. Once at altitude only a few clicks of down-trim are needed. I heard a flapping noise and thought the engine cover had come loose. I did a slow and low fly-by, AND? it?s just the pilot?s scarf. Boy, that motor is quiet.
Stability: Even with the wing reinforcing I can still see wings flex. And I mean flex of both wings, and especially the wing tips of the top wing. I pulled out of a few steep dives to observe this. It made me kind of nervous, but I have faith in the carbon fiber. That stuff will flex a lot before it snaps. This is actually a good thing since the induced dihedral will make the plane stable. I am able to fly it hands off. If I put a little bank in it, it will circle around me by itself. The big 10x4.7 prop allows the plane to fly slowly, similar to the Tiger moth. Since the TM has a more severely under cambered wings it seems to develop more lift at any given speed. Glide is nice and shallow.
Response: I use full throws with 50% exponential. The ailerons let me bank very nicely with little adverse yaw. It is great to be able to level out the plane without touching the rudder. With the Fokker's CG in the recommended location, it is not twitchy even with the flat wings (no dihedral added by me that is).
Performance: This out runner motor is nearly silent. Truly impressive. You have to try it to believe it. I have a climb-out of about 35-40 degrees WOT. Stall is at a very slow air speed and predictable with slight wing tip drop. It will loop from level flight, but the loops are not gigantic. This is probably due to the low top end speed. The ailerons roll it, yet they are hardly axial rolls. I did not try inverted flight?next time.
Conclusion: on a 1200 mah lipo I flew for over 23 minutes! When the cutoff took out the motor I glided in. Very fun to pilot. It has a moth-like glide as I mentioned before and the paint scheme looks great in the skies over Europe. Very easy to fly and no damage to the motor mount with landing in the grass--the prop saver stayed intact. Next I will change the prop to add more speed, and try to find a runway for take-off and landings.
|Here are more details and pictures at RC Groups|