Right thrust.

[Sean Eltringham]

Hello all.

I'm currently putting together an Seagull Decathlon EP. After fitting the motor to the mount and attaching it to the firewall, I noticed that there didn't seem to be any right/down thrust on the motor. In fact with the prop on it looks like it actually has about 1 degree of up thrust. 

Should I had the right/down thrust with washers on the motor mount or does anyone have a solution to this already?

I'd appreciate some help with this please.

Sean

[David Ashby - Moderator]

Hi Sean, I built mine a while ago now (haven't got it any more) and it flew fine without sidethrust. I didn't fly it with any down thrust added either - again I didn't notice any unwanted tendancies although the odd degree of downthrust wont be a problem if you wanted to add some.

I would fly it first and see what you think, you'll probably be fine as it is  

[Sean Eltringham]

Thanks David.

I didnt fancy launching a flying crab. If yours flew fine i'll give it a go.

By the way,  your review of the plane in RCM&E makes a handy addition to the instruction manual whilst building.

[David Ashby - Moderator]

Good, thank you  

 

[Bill Fleming]

While we're on the subject of down/right thrust, could someone please explain why such motor settings are necessary.   Many thanks.

[Sean Eltringham]

Bill

As I understand it, it is to counter act the torque from the prop and allows the plane to track straight.

[Andy Gates]

I believe the need for side thrust comes from the reaction of the tail feathers when the corkscrewing air flow from the prop hits the surfaces.

The need for downthrust comes from the lines of action from the total thrust, total drag which do not necessarily occur at the same vertical point.

I hope this makes sense.