• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Help! Torque roll (rear mounted engine)

shadeyB

Well-known member
#1
Pilots
Had some torque roll on launch with my rear mounted Hawk today πŸ˜­πŸ˜­πŸ˜‚πŸ”₯πŸ’₯

I expected some but not full roll and ditch into ground πŸ”₯ didn’t feel much when I was adjusting throttle

Throttle was only 1/4-1/3 which was around same as I usually launch planes albeit pullers and mid mount engines (my 1st rear mounted)
I feel how much the plane is pulling , adjust throttle so when I let go there is pull in the plane ( I don’t do full throttle launches - those guys are crazy)

Looking for tips , tricks and advice on hand launching rear mounted prop while you are flying solo πŸ˜‚πŸ˜‚πŸ˜‚ not the easiest

My understanding is that if the plane is launched around the same speed as the throttle speed is set at , once you have air flowing over the wings, torque roll is cancelled out to an extent ?
Help I want to fly my Hawk not dig the ground with her
 

Merv

Well-known member
#2
Looking for tips , tricks and advice on hand launching rear mounted prop while you are flying solo πŸ˜‚πŸ˜‚πŸ˜‚ not the easiest
It’s easy to induce a roll while hand launching. I had the same problem until I started using a underhand frisbee toss launch.

Here is a video that demonstrates 3 way to hand launch a pusher. You need to find the method that works for you.

 
Last edited:

shadeyB

Well-known member
#4
It’s easy to induce a roll while hand launching. I had the same problem until I started using a underhand frisbee toss stile launch.

Here is a video that demonstrates 3 way to hand launch a pusher. You need to find the method that works for you.

Lol I hear you, launching wings like this yeah no problem there’s a bit structure there πŸ‘
Thing is my Hawk wings are only 1 sheet think and if I were to hold like he does it would snap πŸ˜‚πŸ˜‚
 

Piotrsko

Well-known member
#6
I may be wrong here but it's not torque that is doing the roll, it is what I understand to be called P-force, a turning caused by gyro precession of the prop. ( try instant full throttle on a taildragger and you get prop eating ground loops) In other words, you ain't got enough rudder force at low airspeeds. CAREFULLY take the plane and yaw it violently with the prop running and you will see a nose down and left coupling that is fairly strong. Add that to the poor performance of control surfaces at slow speed...... waller!!! Note this is for standard prop rotation, it's nose up and right for left hand props, which could be an improvement. I should try it sometime since I hate discus launching my KFM.
 

shadeyB

Well-known member
#7
I may be wrong here but it's not torque that is doing the roll, it is what I understand to be called P-force, a turning caused by gyro precession of the prop. ( try instant full throttle on a taildragger and you get prop eating ground loops) In other words, you ain't got enough rudder force at low airspeeds. CAREFULLY take the plane and yaw it violently with the prop running and you will see a nose down and left coupling that is fairly strong. Add that to the poor performance of control surfaces at slow speed...... waller!!! Note this is for standard prop rotation, it's nose up and right for left hand props, which could be an improvement. I should try it sometime since I hate discus launching my KFM.
Lol might change prop direction & watch it roll the opposite direction πŸ˜‚πŸ’«πŸ’₯
The thing is the wing is too thin to be grabbing and frisbe launching
Guess I’m just going to keep throwing it at different throttle positions and angles, repair it and try again until I figure it out

The P-force factor is too much information ie. asymmetric propellor loading
For every action there is a equal and opposite reaction
 

shadeyB

Well-known member
#8
I may be wrong here but it's not torque that is doing the roll, it is what I understand to be called P-force, a turning caused by gyro precession of the prop. ( try instant full throttle on a taildragger and you get prop eating ground loops) In other words, you ain't got enough rudder force at low airspeeds. CAREFULLY take the plane and yaw it violently with the prop running and you will see a nose down and left coupling that is fairly strong. Add that to the poor performance of control surfaces at slow speed...... waller!!! Note this is for standard prop rotation, it's nose up and right for left hand props, which could be an improvement. I should try it sometime since I hate discus launching my KFM.
While gently holding her vertical, a feeling thrust achieved & b her roll rate (albeit in static position)
She automatically rolls opposite from prop direction , more thrust = more roll
Can this be cancelled out in any way ? Thrust angle for example ? Or is it the magic of air speed and trim that resolves this ?