Mike Hollison's P-51 Slope Soarer (Rimfire .10)
04-18-2011, 11:35 AM
#27
RE: Mike Hollison's P-51 Slope Soarer (Rimfire .10)
Today is the only day for flying before "winter returns", according to the NWS, so down to the field I went.
In a nutshell: she flies great. She'll go very fast, if I let her, and will turn on a dime. I especially like getting way up high, then chopping the throttle and making a series of high speed, gliding turns that are just short of a dive. I love listening to the wind whistling through the fuse and out the ESC cooling vent. I flew for maybe a total of 20 minutes, including four ROGs, and didn't use half of either battery pack. She flies real sweet throttled way back and cruising around to conserve the power.
The only correction she needed was to change the elevator servo. My old HS 81MG got all stupid during flight, and it was very difficult to maintain steady pitch. I had to put in a full size one, so she picked up almost two oz of weight, but it doesn't seem to affect the performance at all. In fact, she may be a bit on the light side for sloping, as the wind started picking up and shearing around this afternoon, and she was getting bounced around quite a bit.
I did both ROG takeoffs and a hand launch. I used one of the mixes in the radio to slave the elevator to the flap "down" swtich, so as to get about an eighth inch of "up" elevator trim (over the normal, level flight setting) during launch, so she'll establish a positive climb angle right away. I pop the switch off as soon as I can get my right fingers on the main stick.
For anyone who decides to build one, the handling is good, but she has a really vicious overbanking tendency if you're turning hard, and you have to be ready to pump in some opposite aileron, or she'll stand on a wingtip real quick. This is normal, I guess, for anything with a really big wing in relation to overall size, coupled with a bunch of diehdral. It is critical to avoid hard turns when close to the ground, as recovery can become an issue real quick.
The other note is that, just like the 3 earlier ones I built from these plans, she needs substantial down elevator trim for level flight. Happily, it is the same for power or unpowered flight. Just shy of 1/4" measured at the inboard ends of the elevator. This is due to a substantial amount of positive wing incidence that is part of the design. I considered putting some positive incidence in the stab so as to lessen the trim required, but with such a small stab/elevator combination, I was afraid of stalling the stab at lower airspeeds, so I left it as per the plans.
I even managed two landings on those itty bitty wheels where she didn't go up on her nose!
In a nutshell: she flies great. She'll go very fast, if I let her, and will turn on a dime. I especially like getting way up high, then chopping the throttle and making a series of high speed, gliding turns that are just short of a dive. I love listening to the wind whistling through the fuse and out the ESC cooling vent. I flew for maybe a total of 20 minutes, including four ROGs, and didn't use half of either battery pack. She flies real sweet throttled way back and cruising around to conserve the power.
The only correction she needed was to change the elevator servo. My old HS 81MG got all stupid during flight, and it was very difficult to maintain steady pitch. I had to put in a full size one, so she picked up almost two oz of weight, but it doesn't seem to affect the performance at all. In fact, she may be a bit on the light side for sloping, as the wind started picking up and shearing around this afternoon, and she was getting bounced around quite a bit.
I did both ROG takeoffs and a hand launch. I used one of the mixes in the radio to slave the elevator to the flap "down" swtich, so as to get about an eighth inch of "up" elevator trim (over the normal, level flight setting) during launch, so she'll establish a positive climb angle right away. I pop the switch off as soon as I can get my right fingers on the main stick.
For anyone who decides to build one, the handling is good, but she has a really vicious overbanking tendency if you're turning hard, and you have to be ready to pump in some opposite aileron, or she'll stand on a wingtip real quick. This is normal, I guess, for anything with a really big wing in relation to overall size, coupled with a bunch of diehdral. It is critical to avoid hard turns when close to the ground, as recovery can become an issue real quick.
The other note is that, just like the 3 earlier ones I built from these plans, she needs substantial down elevator trim for level flight. Happily, it is the same for power or unpowered flight. Just shy of 1/4" measured at the inboard ends of the elevator. This is due to a substantial amount of positive wing incidence that is part of the design. I considered putting some positive incidence in the stab so as to lessen the trim required, but with such a small stab/elevator combination, I was afraid of stalling the stab at lower airspeeds, so I left it as per the plans.
I even managed two landings on those itty bitty wheels where she didn't go up on her nose!
04-19-2011, 06:22 AM
#31
RE: Mike Hollison's P-51 Slope Soarer (Rimfire .10)
A little update: went flying this am in some very high winds, and had a ball. Happy to report that the overbanking tendency is gone. (I discovered that the CA in the CA aileron hinges had taken a long time to set completely, and the ailerons were not centering properly when the stick was neutralized. I just had to flex the ailerons a little more to get them free again.)
Wish I could have flown longer, but my fingertips got numb.
Wish I could have flown longer, but my fingertips got numb.
04-21-2011, 10:21 AM
#32
RE: Mike Hollison's P-51 Slope Soarer (Rimfire .10)
I think this will be the final flight report, unless I do something really spectacular.
Even with about 0.4 oz of lead in the right wing tip (for counter torque weighting) she still wanted to go left (strongly) during hand launch or ROG. The tail section is so small on this bird that rudder is not very effective at countering that, so I put a washer under each left side ear of the motor mount, which seems to be good for about 2 degrees right thrust. It completely eliminated the tendency to snap left on hand launch, and ROGs are nice and straight, now.
Also related to the very small tail section (in relation to the wing) is that I now have about 5/16" up elevator trim with "flaps down" for hand launch. (Over the level flight trim of about 1/8" down.) She estabishes a positive climb angle right away, and there is no tendency to go for the dirt on a hand launch.
Even with about 0.4 oz of lead in the right wing tip (for counter torque weighting) she still wanted to go left (strongly) during hand launch or ROG. The tail section is so small on this bird that rudder is not very effective at countering that, so I put a washer under each left side ear of the motor mount, which seems to be good for about 2 degrees right thrust. It completely eliminated the tendency to snap left on hand launch, and ROGs are nice and straight, now.
Also related to the very small tail section (in relation to the wing) is that I now have about 5/16" up elevator trim with "flaps down" for hand launch. (Over the level flight trim of about 1/8" down.) She estabishes a positive climb angle right away, and there is no tendency to go for the dirt on a hand launch.
04-21-2011, 02:26 PM
#33
RE: Mike Hollison's P-51 Slope Soarer (Rimfire .10)
ORIGINAL: Mustang Fever
I think this will be the final flight report, unless I do something really spectacular.
Even with about 0.4 oz of lead in the right wing tip (for counter torque weighting) she still wanted to go left (strongly) during hand launch or ROG. The tail section is so small on this bird that rudder is not very effective at countering that, so I put a washer under each left side ear of the motor mount, which seems to be good for about 2 degrees right thrust. It completely eliminated the tendency to snap left on hand launch, and ROGs are nice and straight, now.
Also related to the very small tail section (in relation to the wing) is that I now have about 5/16'' up elevator trim with ''flaps down'' for hand launch. (Over the level flight trim of about 1/8'' down.) She estabishes a positive climb angle right away, and there is no tendency to go for the dirt on a hand launch.
I think this will be the final flight report, unless I do something really spectacular.
Even with about 0.4 oz of lead in the right wing tip (for counter torque weighting) she still wanted to go left (strongly) during hand launch or ROG. The tail section is so small on this bird that rudder is not very effective at countering that, so I put a washer under each left side ear of the motor mount, which seems to be good for about 2 degrees right thrust. It completely eliminated the tendency to snap left on hand launch, and ROGs are nice and straight, now.
Also related to the very small tail section (in relation to the wing) is that I now have about 5/16'' up elevator trim with ''flaps down'' for hand launch. (Over the level flight trim of about 1/8'' down.) She estabishes a positive climb angle right away, and there is no tendency to go for the dirt on a hand launch.
04-21-2011, 04:58 PM
#34
RE: Mike Hollison's P-51 Slope Soarer (Rimfire .10)
She really is. I got into trouble with the flap switch tonite, did a bad launch, and now have some damage to repair in the wing saddle area. NBD. She'll be back in the air sometime tomorrow, weather permitting. I'm going to take out some of the "up elevator" at launch.
I don't think I've learned nearly all that there is to know about this design. I'm gonna keep at it.
I don't think I've learned nearly all that there is to know about this design. I'm gonna keep at it.
04-24-2011, 10:38 AM
#35
RE: Mike Hollison's P-51 Slope Soarer (Rimfire .10)
Two days to repair the damage, and then some serious flight testing. I learned the following and made corrections:
1. There was too much downthrust. Unlike most scale Mustangs, this bird doesn't like that. The thrust line is now very close to neutral, relative to the stabilizer line.
2. I have 4 Zippy 2.2 LiPos. Two of them are from last year, two are new. The newer ones are a bit heavier, and the bird balances fine without ballast when using them. The older ones are just enough lighter to make it tail heavy- hanging a bit tail low on the balance machine. It is enough to cause instability at low speeds, and that was most likely the main cause of the hand launch crash.
After thrust line and CG corrections, I got some really nice hand launches today, and also nice ROGs.
1. There was too much downthrust. Unlike most scale Mustangs, this bird doesn't like that. The thrust line is now very close to neutral, relative to the stabilizer line.
2. I have 4 Zippy 2.2 LiPos. Two of them are from last year, two are new. The newer ones are a bit heavier, and the bird balances fine without ballast when using them. The older ones are just enough lighter to make it tail heavy- hanging a bit tail low on the balance machine. It is enough to cause instability at low speeds, and that was most likely the main cause of the hand launch crash.
After thrust line and CG corrections, I got some really nice hand launches today, and also nice ROGs.
05-25-2011, 06:19 AM
#36
RE: Mike Hollison's P-51 Slope Soarer (Rimfire .10)
Slopin Slopin
This is the best windy weather airplane in my stable. Here in 49601, it's blowing a steady 15 mph gusting to over 20, and the 'stang handles it great. I take off from the ball diamond infield track (ROG), down the hill from the road and mostly protected from the wind, then suck up the landing gear and climb up to over the bus terminal and freeway to the east. The wind hits the US 131/13th street overpass from the south east and creates a very narrow but strong updraft. I'm so far away from the airplane that it's hard to keep it over the lift, but it is sure fun.
I literally cannot wait to get up north this summer and try it at the lake bluff.
I have an unemployed Rimfire 25 that may just find it's way into a 150% version of this design. [:-]
This is the best windy weather airplane in my stable. Here in 49601, it's blowing a steady 15 mph gusting to over 20, and the 'stang handles it great. I take off from the ball diamond infield track (ROG), down the hill from the road and mostly protected from the wind, then suck up the landing gear and climb up to over the bus terminal and freeway to the east. The wind hits the US 131/13th street overpass from the south east and creates a very narrow but strong updraft. I'm so far away from the airplane that it's hard to keep it over the lift, but it is sure fun.
I literally cannot wait to get up north this summer and try it at the lake bluff.
I have an unemployed Rimfire 25 that may just find it's way into a 150% version of this design. [:-]
