FT Storch Question

[bsphotomac@gmail.com]

This is my first kit airplane and I'm new to airplanes.
I'm starting to build a Storch and using a FT Pack C kit. In the build video they mention adding 4% Down Thrust.
Can someone explain this to me.

Bob

 

[Hai-Lee]

Down thrust means that the engine is pointed downwards by the amount recommended (4 degrees). THe angle is measured from the fuselage centre line normally.

The reason downthrust is used is that the motor pushes air backwards, (thrust) and the amount of air being moved varies with throttle setting. Some of this air flows over the wing and tail and can give extra lift especially at high throttle settings. The extra lift causes the plane to climb each time you increase the throttle setting.

To reduce the change in the planes attitude, (climb/dive), downthrust is used where this does reduce the lift generated AND applies a small downward pull on the nose of the plane with the design aim to keep the plane from changing its flight attitude when the throttle is adjusted.

Bob

 

[fliteadmin]

Very well put Hai-Lee! One of the best explanations of thrust angle I have heard!

Thanks for the post!

Blessings,
Stefan

 

[bsphotomac@gmail.com]

Down thrust means that the engine is pointed downwards by the amount recommended (4 degrees). THe angle is measured from the fuselage centre line normally.

The reason downthrust is used is that the motor pushes air backwards, (thrust) and the amount of air being moved varies with throttle setting. Some of this air flows over the wing and tail and can give extra lift especially at high throttle settings. The extra lift causes the plane to climb each time you increase the throttle setting.

To reduce the change in the planes attitude, (climb/dive), downthrust is used where this does reduce the lift generated AND applies a small downward pull on the nose of the plane with the design aim to keep the plane from changing its flight attitude when the throttle is adjusted.

Bob

Thanks for the info. That really helps. When I build it I'll make sure I give it a little down angle. 4 degrees isn't much but I guess it must help control it.
Thanks

 

[mikeporterinmd]

Thanks for the info. That really helps. When I build it I'll make sure I give it a little down angle. 4 degrees isn't much but I guess it must help control it.
Thanks

I'm pretty sure if you follow the plans, you'll get the angle automatically. Just make sure you install the power pod correctly.

Mike

 

[N4RF]

As I think you mentioned, the hard part is the 4 degrees part. I've done this in two ways for other airplanes. The first is to add a small washer under the top screw holding the motor on. 4 degrees isn't much but a small thin washer should do.

The second option and one that I use almost exclusively now is to sand down the front of the pod to the desired angle by rubbing it across some sandpaper. I would draw a line first with that angle and then sand down appropriately. You would then glue the motor mount onto the pod.

Good luck, hope this helps.

 

[nhk750]

Thanks for the info. That really helps. When I build it I'll make sure I give it a little down angle. 4 degrees isn't much but I guess it must help control it.
Thanks

I have watched that video about 15 times now and built 2 Storches and I never saw him mention anything about thrust angle. Maybe I missed it? Anyway, just build it and don't worry about the thrust angle as the aircraft flys great without messing around with that.

Some airplanes do require messing around with thrust angle, but usually there is a special build method in his videos for that if needed. So no worries.

 

[Bayboos]

FT Storch does have downthrust angle built into the design - just like almost all of the FT planes that need it. When you build from the kit, just follow the instructions and you'll get the plane that flies well - that's for sure. If you are still unhappy, you can add some tiny washers later on; but I never had the need to do that in any of the FT planes I built so far.