|Mar 09, 2013, 02:37 PM|
Joined Sep 2010
Addressing Transitional Flight
First want to thank "Foam and Tape" for getting me started on VTOL in 2009. Like Peter, I went the route of mixers, no gyros, even tried my mechanical gyros, electronic gyros, etc. Found that gyros, rx's, esc's can't be sync for motors for liftoff.
Decided to go from VTOL to STOL and was successful for taking off as well as landing. Like anything else, went thru time and time again, crashes!!!! Now I have a EDF setup that has possibilities for VTOL. So I resurrected both airplanes to see what happens. So, rather than crash over and over, I am going to approach transitional flight from the other way.
That is, get airplanes into the air (3 crashes high), and then work on transitional problems back to VTOL. It should offer some think time (altitude)before it crashes. The easiest will be my EDF. As you can see, the thrust range will be vertical to horizontal.(used +45 to -45 for STOL). For twins, will have +95 for range.
My flight testing:
Slowly change angles to cover horizontal to vertical for EDF and loose altitude in process. Review of NASA data suggest slight nose up of fuse makes it much more stable in transition. Will do the same with twins.
My key to STOL success: Look at problem from vector analysis in the air as well as on the ground. It is a whole new way of flying. For instance, thrust line is at angle and you are half throttle(gusty) and want to descend at a nice glide pattern. So it is a "combo of thrust angle change and throttle variation" and when you got it, it is a nice feeling. When you don't, all h-ll breaks out.
Doing STOL, I did not cover the range of all the angles needed, so its going to be a new ball game. Here are some tips that work for me.
1) Twins: you do not need much power to lift or go thru transitional phase. Never really got past 2/3 throttle. Before I retired the twins in 2010, tried a number of VTOL, best results was about 87 degrees(used trim). NASA data tends to agree with this number. Then it crashed and gave up for awhile.
2) EDF: Found best angle to be about 40 degrees for STOL takeoff. Interesting that F-22 acted like hovercraft before it took off. During a very gusty day, actually pointed EDF thrust line below fuse to regain control of plane.
Not having any gyro or any assistance, the 2 keys to success was the rudder control was used to change the servo thrust line and the throttle curve was flatten This all was done in mode 1 and mode zero eliminated the 2 variables. Being old school, I still want to attempt VTOL without any assistance. Only if I am close, will I add electronics. To keep my sanity, left rudder would increase and right rudder decreases thrust line.
If anyone would like me to conduct some specific test, will to give it a go.
|Mar 11, 2013, 03:31 PM|
Don't be afraid to try using the electronic stabalization (flight controllers) that are available. Something like the KK2 board from Hobby King is relatively cheap and doesn't even require a PC interface to get started. It may or may not work for your specific application, but in many cases it can be made to work, and you would be hard pressed to put together that much capability in terms of individual gyro's at 10 times the weight or 10 times the cost.
|Mar 12, 2013, 11:36 AM|
Joined Sep 2010
Thanks for the info.
Yes, that will be my last choice, the electronics. But the fun for me is "the experimentation". Back in 83, the heli Cricket came on the scene and I learned to hover, fly and even barrel roll and loop(an "E" shape really) without a gyro. I took the attitude to never give up looking at it from the engineering perspective.. Also, feel that your radio is a big help. I have 5 modes, 9 mixes, servo speed control, graphical 8 point mixes, so that will should help vertical and transitional flight.
Done my NASA research, picked my plane and power source setup, possible trying 2 new ideas that others haven't used. Will it work, who knows?
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