FT Mini Speedster turning heavily left

[grundrauschen]

Hi all!
I sort of maidened my Mini Speedster this weekend and it flew pretty fast! My only problem is that it turns heavily to the left despite the rudder beeing centered. I also cannot counteract it with trimming. It's simply too much. I can keep it in the air, but I need to be really fast upon start to reach for the transmitter rudder right after throwing....
My question is now if I did something wrong with the angle of the motor. If I look at the plane from above in flight direction, the motor is in an angle to the right. If my physic thinking is correct this is to counteract the rotation power from the prop which is turning counterclock? Do I have not enough of an angle? Or is the angle even in the wrong direction and therefore the plane is flying left?
I hope to get some input here to find out what went wrong

 

[Bonards]

Hi groundrauchen,

This happen only when you apply power? If yes, did you glue the wing in right place? I remember in the build video that Josh told to not center the wing with the fuselage, so the left wing is a little longer to compensate the thrust.

If is it, than you may need to adjust the rudder to be centralized in the radio (0% trim) but with the rudder a little to the right. Other thing that you could do is to put some washers at the left screws of the motor mount, to turn it a little to the right, but use a thin washer, put one and see what happens, than if it's not good yet put another one, until it flies stable.

 

[grundrauschen]

Thanks for the tips Bonards,
actually Josh advises in the video for the mini not to glue the wing to prevent damages. I will recheck center and if it's perpendicular though.
Does it appear without thrust? Well, good question! I think I never tried it in my first 3 flights. Good idea! I only cut throttle right before landing.

 

[Elexo]

FT Airframes are usually designed to use CW (Clockwise) rotation. Could you be using CCW? I have to be sure of this every time I fly my Old Speedster.

 

[Bonards]

Thanks for the tips Bonards,
actually Josh advises in the video for the mini not to glue the wing to prevent damages. I will recheck center and if it's perpendicular though.
Does it appear without thrust? Well, good question! I think I never tried it in my first 3 flights. Good idea! I only cut throttle right before landing.

Sorry, I messed up a little, I didn't read the "mini" in the tittle

But if you could try to reduce the power, or cut the throttle, during the flight, it should give to us more clues of what's happening. Just make sure to have some altitude before try it.

 

[Grey Beard]

I have the exact same problem with my mini speedster. Happens on and off throttle. Everything 'looks' straight and square where it should. Power pod is angled the right direction. Even with a pretty good amount of right rudder trimmed in it still wants to fly to the left some, and doesn't seem very stable. I've double checked balance points, throws, control surfaces... I'm sure its something simple and captain obvious worthy, but it has eluded me so far.

I was in hope that this would be a relaxing flyer with some spunk when you wanted it, but relaxing it has not been as of yet.

 

[Chameleon257]

The other thing to check is make sure you made the power pod with the right thrust angle if you glued the firewall on the other side the thrust angle would be straight which would cause this.

Make sure the wing is centered, make sure the wing is cambered correctly as in all the same angles, and of course make sure the wings tips are angled the same.

I've made a lot of these aircraft and fly them quite a bit easy flyers I've never had the problems listed here.

 

[Chameleon257]

Hi all!
I sort of maidened my Mini Speedster this weekend and it flew pretty fast! My only problem is that it turns heavily to the left despite the rudder beeing centered. I also cannot counteract it with trimming. It's simply too much. I can keep it in the air, but I need to be really fast upon start to reach for the transmitter rudder right after throwing....
My question is now if I did something wrong with the angle of the motor. If I look at the plane from above in flight direction, the motor is in an angle to the right. If my physic thinking is correct this is to counteract the rotation power from the prop which is turning counterclock? Do I have not enough of an angle? Or is the angle even in the wrong direction and therefore the plane is flying left?
I hope to get some input here to find out what went wrong

From the cockpit is the prop spinning clockwise? That is the correct direction of the prop.

 

[Capt_Beavis]

What sized prop are you using? Most of the mini's have some torque steer and a higher pitch prop will make it worse. What battery are you using? One thing to test. Get the plane up high, cut the throttle and let it glide. If it turns left in a glide than you need to add some trim. If it goes straight in a glide but turns left under throttle you can set up some mixing to rudder as throttle increases or just be prepared to compensate.

 

[Grey Beard]

I have no idea what motor/prop grundrauschen is using, but I am using a 1704 1900kv with a 5x5E prop. I've tried with both a 2S 800 and a 3S 500 pack with the same results. Left turn seeems to happen both ON and OFF throttle. So I don't know that it would be 'torque steer'. I'll recheck all my control surfaces and thrust angle and wing/elevator/rudder alignment, and give it another go. Thanks for the suggestion on mixing. I'll definitely keep that in mind.

I hope grundrauschen is having better luck.

 

[Chameleon257]

I fly my speedsters with 800mAh 3S with a 6 x 3 on a 1806, 2280KV motor with a BL Heli 12A ESC. I get flight times of 15 Minutes per battery and they have very good performance even slow flight.

 

[Capt_Beavis]

5x5 is pretty agressive, try a 5x3 or a 6x3.

I have no idea what motor/prop grundrauschen is using, but I am using a 1704 1900kv with a 5x5E prop. I've tried with both a 2S 800 and a 3S 500 pack with the same results. Left turn seeems to happen both ON and OFF throttle. So I don't know that it would be 'torque steer'. I'll recheck all my control surfaces and thrust angle and wing/elevator/rudder alignment, and give it another go. Thanks for the suggestion on mixing. I'll definitely keep that in mind.

I hope grundrauschen is having better luck.

 

[Wanderfound]

To be clear: if, from the POV of your cockpit, the prop is moving clockwise, then the motor should be angled slightly to the right (again, from the POV of the cockpit). If the prop is going counterclockwise, then it will need to be angled slightly to the left instead.

Incidentally, this has nothing to do with "torque steer"; torque reaction produces a rolling response, not a yawing one. It's because, when flying with positive AoA, the pitch of the blade is effectively steepened on the downstroke and shallowed on the upstroke, producing asymmetric thrust (which we use thrust angle to compensate for).

If you don't have your thrust angle backwards, then my next suspect would be a crooked fuselage. Is the vertical stabiliser absolutely in line with the axis of the plane?

 

[TNSTEMDOG]

I have had similar issues with both the speedster and the scout. What I am finding out is that it is most pronounced during full power low airspeed. Just like full-scale I think I am experiencing asymmetrical thrust and P-factor. I went back and rebuilt the power pod making sure of the correct thrust angle and no problems now.

 

[grundrauschen]

I'm sorry for returning so late to this topic, but I somehow missed to subscribe it - beginners fault I guess....

Anyways, I'm using the recommended setup for the motor with the Emax 1806 and a 6x4E prop. It does turn clockwise if you look at it from the perspective of the pilots seat. Battery is a turnigy nano 480mAh 3Cell - and the machine runs really fast with that. First I feared the prop would burn the motor because of beeing so big, but it stays cool. Only flight time is about 4 minutes if I push it hard.

This and the angle of my motor mount is correct. I did another flight after the first tips here and came to the conclusion that the plane turns left independently from the motor running.
So I concentrated on fixing the angle of my wing which was pointing down to the left if seen relative to the horizontal stabilizer. It's straight now, but my fuselage is somehow not perpendicular - which I cant fix anymore. But it turns out I don't need to! It flies straight now! Yay!!!

Second thing I did was strengthen the elevator in the middle with some music wire because the servo arm was only able to move one part of the elevator as it was. This added even more to flying straight.

I'm really happy with my speedster now! I only need some bigger batteries for a bit of longer flight times. Or I need to fly it more slowly, which looks great but is only half the fun

 

[Chameleon257]

Awesome I love flying mine even in wind.