FallDownGoBoom
Posts: 194
Joined: 10/12/2003
From: Colbert,
WA, USA
Status: offline
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OMIGOD, IT FLIES! 
Weather was good this weekend, but with a vicious crosswind, discretion was the better part of valor on Saturday. But on Sunday... no excuses.
First try (with new wheels and lighter nose weighting): still not enough speed for takeoff  Ended up in the weeds.
Second try (re-tune the engines, and have a fellow flyer hold it during initial run-up): almost! After about 400 ft run (and full up elevator) it bounced about 3" off the ground, then settled back and ran into the weeds... no damage, but... 
Fellow flyer flew his Sig 4* 60 for a bit (nice plane!) and we decided to try again. Tweaked the engines a little more, but when he took it out to the runway all I said to myself was "Secret weapon time!" and dropped the flaps. Ran up the engines, he let her go, and about 200 feet later I pulled full elevator, and up she goes as nice as you please! Gained a little altitude, and as airspeed rose the nose seemed to want to pitch down so I raised the flaps and kept climbing. Gentle left turn, now about 100 feet up, backed off the throttles a little, and ... gotta keep some up elevator in all the time, otherwise it starts to lose altitude. Full "up" trim still doesn't solve the problem, no yaw or roll tendencies, but it's definately pitching down.
This of course makes right/left turns real interesting, but not ultra-difficult. Mostly cruised around at between 50-75% of throttle getting the feel of the plane, doing straight & level/circles/figure 8's with both ailerons and rudders. Feels like it flies about the same speed as my Arrow trainer, and no bad habits in the air.
Landing time: brought her around, but couldn't really judge the sink rate because of the down-pitch problem. I was going to do a couple of passes at altitude, but the first approach looked so good that I just brought her straight-in, hotter than I'd like but a nice landing anyway.
So the maiden's in the book. Only flew the Bronco once, and sorry, no pictures or video yet. Some things to experiment with:
1) Controlling the down pitch: I suppose it could be the CG being too far forward, but I've got neutral balance on the CG machine, so my suspicion is that either the flaps aren't totally retracted (but they looked OK after landing) or there's a little bit of positive/negative wing/stabilizer incidence that's causing the plane to dive. I can re-attach the horizontal stab with some shims to see if that will fix the problem. Other ideas?
2) I agree with Randy's comments on the elevator: seems a bit small, and until you get enough airspeed, it's control effects are minimal. Because I can take the whole HS/elevator assembly off, I may re-build it this winter and widen the elevator from the 1-1/4" it is now to around 2".
3) See how it flies with the flaps down, hopefully that will slow approach speed.
Needless to say, I'm pretty happy. Great to see a box of sticks become a real aircraft! Oh yeah, there's another problem: the engine sound causes orgasms when you bring it down the runway!
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All Forums >> RC Airplanes >> Twin & Multi Engine RC Aircraft >> RE: OV-10 Bronco 52" 3-Blade Prop Size? 
RE: OV-10 Bronco 52" 3-Blade Prop Size? - 
? When I was on vacation I ended up reading a book about George McGovern and his experiences flying B-24's during WWII. From what I read, the Liberator took an extreme amount of both physical strength and mental concentration to fly. It had absolutely no pilot/crew amenities, with mission temperatures of 25 to 50 degrees below zero. Gives one a better appreciation of what our fathers/grandfathers went through during the war.
and took off. It definitely made a difference, as I was able to get off before using up all of the runway. However, since I didn't pay attention to the flaps down condition, and wondered why it was climbing so rapidly, I had to put in a lot of down trim. Figured it out after landing 
. Clearly, raising the angle of attack on the wing will help on takeoff. Just be careful to not get into too high of an angle of attack at takeoff. Having done that, I found the airplane right at the stall and it was very exciting to level the wing, dive to the ground, and try to keep the speed up. Many thanks to the radio manufacturers for exponential. One good thing about that, though, is that the airplane is very capable of flying through problems like this. Good luck on your first flight. Lee