|
|
08-24-2014 05:45 PM | |
tommy |
Re: take off wing stall help I had a .47 GMS in a .40 sized cub and ground rolled it almost every time. After a time I did not jam in the throttle on take off, I slowly added throttle and let the plane get to that speed and added more throttle until I was a little over half throttle, then I gently gave the up signal and I was flying, at around forty feet I had speed up and leveled off. If I got out of order on the ground, I started over again after trying to find my problem, with a different approach. Also I added washout to my wing tips, I think it helped. I ran a 10x7 prop which may have been part of the problem also. I also have a 1/5 scale cub powered with a .47 and on its maiden flight I handled it the same as the .40 and it took off on it's own when it reached flying speed no elevator needed. |
08-22-2014 08:30 AM | |
cessna180 |
Re: take off wing stall help I have not worked through all of the suggestions. Like I stated, all the other solutions may work. I just posted what works for me and it may be of help to others. In addition I also installed gap seals on the ailerons using hinge tape that is for small foam models. |
08-21-2014 07:12 PM | |
strikemaster |
Re: take off wing stall help cessna180, have you had a chance to work through the list of suggestions provided and figured out the probable cause? |
08-20-2014 05:54 PM | |
cessna180 |
Re: take off wing stall help I agree that everyone's suggestions regarding take off wing tip stall should help. Here are my two cents worth. I scratch built this aircraft from my own drawings. It is built out of dollar store foam board (the wings) and 3/8 foam board for the fuselage and tail feathers. Tail feather leading and trailing edges, the wing trailing edges and ailerons are balsa. It is painted with Home Depot paint by brush. The aircraft turned out heavy at 6 lbs. 12 ozs. gross, which is to heavy for 600sq. inches of wing. Power is a Hyerion 4020- 777kv. 4s 5000ma. The paint job required too much paint. Now this is my way of checking the GofG, longitudinally and latterly. After the initial flight the control throws way were to high. Landing speed was high and it wanted to stall on approach. Of course I could not put wash out in the foam wing. The fix for the washout was to install leading edge cuffs on the outboard half of the wing. (like slats on a high performance aircraft) This aerodynamically produces washout. Also the aileron throws were adjusted with differential to 1/4 in. up and 3/16 in. down. Elevator 1/2 in. up 3/8 in. down. Rudder 3/8 in. on low rate. Wing incidence is 1 degree positive and the stab at 0. Motor is at 2 degrees rt. thrust and 2 degrees down thrust. My other comment regarding take offs is that if the aircraft is straight and true and set up correctly it should almost take off by itself. It will fly when it is ready to fly. With the modifications the aircraft handles much better.and is easier to fly. The power set up provides ample power (750 watts - 13/7 prop.) |
08-20-2014 03:28 PM | |
bcsaltchucker |
Re: take off wing stall help in that vein ... try dialing in more expo or even go to dual or triple rates, or even program 'flight modes' later on once you get this model figured out. and +1 on opposite rudder. There is more than torque going on. there is also slipstream possibly wrapping the fuse and hitting one side of the rudder |
08-20-2014 02:07 PM | |
Jsp |
Re: take off wing stall help Like said above, I've seen your videos, and well........ I think I would just link it to pulling too soon and too much throw in your flying surfaces Pulling too soon when you don't have the wind over the wing surface will get the plane airborne for a split second. But still doesn't have enough airflow to fly will do exactly as you're describing. |
08-19-2014 12:31 PM | |
cosmith |
Re: take off wing stall help Everything mentioned here is good...but honestly, if it is rolling so violently that you can't correct and it hits the ground, with multiple different planes, then I have to think you are using way too much elevator way too early in your take off roll. This is my first year flying but I've flown about a dozen planes now. The couple that have had that left roll tendency on take off are easily tamed with a little rudder and/or a little aileron. For me, the worst planes for this have been high wing tail draggers with lots of dihedral, but they are the easiest to correct for, just a little right rudder on take off. My tail dragger take off process on the grass field where we fly: 1. Hold full up elevator for all taxiing to avoid nose over. 2. Once you're ready to take off, throttle up smoothly (still holding full up elevator)...amount of throttle depends on plane. My overpowered 3D planes would get away from me quick taking off at full throttle. 3. As the plane accelerates and you have more airflow over the control surfaces I smoothly ease off the elevator. A very small amount of up elevator at the time of lift off will give you the best take off. As soon as the wheels are free of the ground the plane will accelerate much better, so if you choose you can jam on full throttle at that point and climb out more aggressively...the success of this is going to depend on the plane of course. Steps 2 and 3 happen simultaneously, as the throttle goes up the the elevator comes down...kind of like applying throttle and releasing the clutch in a manual transmission car. If you just can't get it, then have a more experienced pilot try flying them. That will rule out problems with the plane, plus they can get it all trimmed up nice for you before you fly. Aside from that, if you have a simulator, practice taking off an landing over and over again. Once you have that muscle memory for the basics you're planes will last a lot longer. |
08-19-2014 09:18 AM | |
Flypaper |
Re: take off wing stall help No washout mentioned either. Make sure the wingtips are twist down at the leading edge a bit. Equal on both sides. Depending on the size of the plane, 1/8 to 1/4 in. |
08-18-2014 06:13 PM | |
kip51035 |
Re: take off wing stall help Yeah lateral balance. |
08-17-2014 09:12 PM | |
jsparky |
Re: take off wing stall help There is one point that has not been mentioned here yet.. and very particularly if it has a side mount engine.. and as important as your CG Lateral balance... |
This thread has more than 10 replies. Click here to review the whole thread. |