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Help! Odd takeoff

Ryan O.

Well-known member
#2
I have a few questions to help:
1. were you using a reverse prop
2. did you check aileron and rudder controls before the flight
3. was there a crosswind or a tailwind
These are all things I have done wrong before, so I hope I can help figure out what went wrong 🙂
 

BATTLEAXE

Well-known member
#5
Thanks for the ideas. It seems things would not be because of a out of line control surface and since it was in my living room it did not have a ton of speed

I will see about the prop though.
Well that might be your problem, not enough speed means you tip stalled. The wing wasn't ready to lift yet and there was to much up elevator way to soon
 

BATTLEAXE

Well-known member
#6
Thanks for the ideas. It seems things would not be because of a out of line control surface and since it was in my living room it did not have a ton of speed

I will see about the prop though.
Well that might be your problem, not enough speed means you tip stalled. The wing wasn't ready to lift yet and there was to much up elevator way to soon
 

Hai-Lee

Old and Bold RC PILOT
#10
Thanks for the ideas. It seems things would not be because of a out of line control surface and since it was in my living room it did not have a ton of speed

I will see about the prop though.
Sorry for the late response but you should look at something called "P" factor!
The thrust from the prop spirals along the fuselage and actually exerts a sideways push on the vertical tail. This force is relatively small and is why sidethrust is included in most designs. Sadly when the plane tries to take off when the airspeed is too low the control surfaces are far less effective. The force from the "P" factor causes the plane to want to turn and at low speed this can cause the plane to have lift on one wing and no lift on the other, (or very little). The total effect is to have the plane turn and roll to the same side and no control surface input can correct it.

The solution is only to take off at a speed where all control surfaces are functioning sufficiently to correct such a turn and roll tendency. During a high speed take off, the effect of "P" factor, (on a plane with adequate side thrust), is very small as lift and control forces are great.

The best idea is to never attempt to do a very slow take off on a plane that is not designed specifically for such.

Have fun!
 

BATTLEAXE

Well-known member
#11
Yea any take off needs a good run up. The wing needs to produce lift before a successful smooth launch can happen. A plane can produce enough thrust to move on a lateral axis but when lift is introduced by the wing the work load has now doubled. In a straight run up on the ground the only force it is working against is drag. Once lift is produced the next added obstacle is gravity. So as soon as the plane leaves terra firma it immediately slows down, if there is not enough momentum it will still and drop a tip.

Have you tried it outside yet?
 

Ryan O.

Well-known member
#12
Sorry for the late response but you should look at something called "P" factor!
The thrust from the prop spirals along the fuselage and actually exerts a sideways push on the vertical tail. This force is relatively small and is why sidethrust is included in most designs. Sadly when the plane tries to take off when the airspeed is too low the control surfaces are far less effective. The force from the "P" factor causes the plane to want to turn and at low speed this can cause the plane to have lift on one wing and no lift on the other, (or very little). The total effect is to have the plane turn and roll to the same side and no control surface input can correct it.

The solution is only to take off at a speed where all control surfaces are functioning sufficiently to correct such a turn and roll tendency. During a high speed take off, the effect of "P" factor, (on a plane with adequate side thrust), is very small as lift and control forces are great.

The best idea is to never attempt to do a very slow take off on a plane that is not designed specifically for such.

Have fun!
Now I remeber what the name of that was. I read about it in a book called stick and rudder, and couldn't remember the name since.
 

FoamyDM

Building Fool-Flying Noob
#13
... since it was in my living room it did not have a ton of speed.
Wait... you took it off in your living room? this is an 1806 size motor (5" prop) plane. How big is your living room?! how tall? I know I've seen some big-uns and I've done some tests things in my home... but wow! (by the way, I'm envious a bit. Just like those with a yard big enough launch out their back door.)

@Hai-Lee has it right. does the power pod have an angle on it?
 
#15
Wait... you took it off in your living room? this is an 1806 size motor (5" prop) plane. How big is your living room?! how tall? I know I've seen some big-uns and I've done some tests things in my home... but wow! (by the way, I'm envious a bit. Just like those with a yard big enough launch out their back door.)

@Hai-Lee has it right. does the power pod have an angle on it?
I did not actually take it off in my living room just taxied it around because I was excited that I was done with the build
 

FoamyDM

Building Fool-Flying Noob
#17
I did not actually take it off in my living room just taxied it around because I was excited that I was done with the build
I know the feeling.:)
@Portlandbeginner - I wasn't trying to be mean. Per your name, you are a beginner. My comment was meant to either, let you know how jealous I am of your large enough living room in a fun way, or let you know how concerned we all get about indoor prop testing... ask anyone here who thought they had it in hand, but didn't. :eek: (raises hand sheepishly. I didn't get hurt, just scared)
I taxi in my entry hall.. so I've got maybe 8' of space. on occasion, I nearly lost some shin skin as a result of reversed throttle. Now I ALWAYS stand behind the craft or behind an obstacle. I nearly lost a micro nerdnic tiger moth flying it at 11:30 out front of my house and into the neighbor's fenced in back yard, because that's when I was done building it!:LOL::cry: It all worked out, point is please protect you and your loved ones in case it goes awry. test motor spin with the prop off. Taxi out side if you can. We want you to spend time flying, not in a hospital or urgent care facility.

motor torque is a real thing, and that 4-5° angle on the pods is to help counteract it.
 

FDS

Well-known member
#18
I am always extra careful, I have a blind dog at home and run away planes don’t mix well with pets, so I don’t taxi either, I use my workshop for that if it’s raining. My flying field is 2 mins from my house too so it’s not so bad.
 
#19
I know the feeling.:)
@Portlandbeginner - I wasn't trying to be mean. Per your name, you are a beginner. My comment was meant to either, let you know how jealous I am of your large enough living room in a fun way, or let you know how concerned we all get about indoor prop testing... ask anyone here who thought they had it in hand, but didn't. :eek: (raises hand sheepishly. I didn't get hurt, just scared)
I taxi in my entry hall.. so I've got maybe 8' of space. on occasion, I nearly lost some shin skin as a result of reversed throttle. Now I ALWAYS stand behind the craft or behind an obstacle. I nearly lost a micro nerdnic tiger moth flying it at 11:30 out front of my house and into the neighbor's fenced in back yard, because that's when I was done building it!:LOL::cry: It all worked out, point is please protect you and your loved ones in case it goes awry. test motor spin with the prop off. Taxi out side if you can. We want you to spend time flying, not in a hospital or urgent care facility.

motor torque is a real thing, and that 4-5° angle on the pods is to help counteract it.
Its ok I did not think you were being mean at all;) I just wanted to say.