evranch
Well-known member
I do aerial mapping on my farm with a large, heavy, underpowered plane, the Bormatec Maja. With the change in regulations this year I plan to branch out and do some contract work. Trouble is, the Maja is a great flyer that's hard to get into the air. With a takeoff weight of 3300-3900g (7.2-8.5lbs) and a 30A motor and ESC, my takeoff roll is realistic to say the least. A couple hundred feet without wind. I yardsaled it last week when I clipped a hard snowdrift and was bounced into the air prematurely. Not enough airflow over the control surfaces = lots of pieces to pick up.
It can be hand launched with a hefty two hand toss into the wind, but with the pusher motor I am relying on my FC to sense the toss and spin up the prop after it's away - and the time it takes to spin up means every launch barely misses the ground (or sometimes doesn't, if the wind isn't strong enough...)
Flaps are counterproductive as the added drag cancels out the improved stall speed, and I need even more runway.
Current power package:
- 30A ESC
- Pichler Boost 25: 980kV 30A max
- APC 12x8E
With this setup I can cruise at 8A on a calm day, which gets me the better part of an hour in the air with a 7700mAh. I used to swing an 11x5.5E which could achieve the same cruise at 5A due to the better pitch speed, but takeoffs were even more marginal.
I'm seriously considering ditching the pusher for a pair of power pods on the wings, swinging the same 12x8E or the more efficient 11x5.5E.
- double the static thrust
- better weight balance, more options for camera and battery placement
- differential thrust for better yaw control while mapping
But everyone knows that in the real world, twins are fuel hogs. Does this carry over to RC scale?
Other options?
- More powerful pusher motor
- Keep the pusher motor for cruise, and only use wing motors for takeoff?
- Add a tractor motor and folding prop for takeoff, which will give me more thrust and more airflow
- Quadplane VTOL/STOL? Too heavy to be practical, I think.
It can be hand launched with a hefty two hand toss into the wind, but with the pusher motor I am relying on my FC to sense the toss and spin up the prop after it's away - and the time it takes to spin up means every launch barely misses the ground (or sometimes doesn't, if the wind isn't strong enough...)
Flaps are counterproductive as the added drag cancels out the improved stall speed, and I need even more runway.
Current power package:
- 30A ESC
- Pichler Boost 25: 980kV 30A max
- APC 12x8E
With this setup I can cruise at 8A on a calm day, which gets me the better part of an hour in the air with a 7700mAh. I used to swing an 11x5.5E which could achieve the same cruise at 5A due to the better pitch speed, but takeoffs were even more marginal.
I'm seriously considering ditching the pusher for a pair of power pods on the wings, swinging the same 12x8E or the more efficient 11x5.5E.
- double the static thrust
- better weight balance, more options for camera and battery placement
- differential thrust for better yaw control while mapping
But everyone knows that in the real world, twins are fuel hogs. Does this carry over to RC scale?
Other options?
- More powerful pusher motor
- Keep the pusher motor for cruise, and only use wing motors for takeoff?
- Add a tractor motor and folding prop for takeoff, which will give me more thrust and more airflow
- Quadplane VTOL/STOL? Too heavy to be practical, I think.