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An old fogey with old fogey troubles

#1
Having built the old fogey because it looked so easy to fly (I am a complete newbie to the hobby) I am getting really frustrated because it doesn't.

I've balanced it so it is a little nose heavy with my finger tips under the break in the wing, but when I launch it, it just see-saws, each see or saw getting worse until it turns on its back and dives into the ground (flight time about four seconds).

Does anyone have any suggestions as to what I need to adjust/

Thanks.


Andy
 
#2
Is the "see sawing" a porpoising motiong? If so, you might want to look at some nose down trim on the elevator and make sure the angle of incidence for elevator is correct.... Just a thought.
 

xuzme720

Dedicated foam bender
Mentor
#4
Welcome to the forum!
If it's side to side, one wing goes up then the other, they tend to do that some just like any other polyhedral plane. It shouldn't be that violent though. Have you tried a glide test with the motor off? Find an open area with some tall grass if possible. Now, with the motor off, give her a solid chuck at the horizon so you are throwing it level or at a slight downward angle. Don't try to put in any control except elevator and see what she does. Definitely make sure the landing area is as soft as you can find and free of obstacles. This should point out any balance issues as if it just dives to the ground, you are nose heavy and if it first climbs then dives, it's tail heavy.

on edit: I see it is roll that is giving you the trouble. I'm just not sure why it's flipping like that unless... are you trying to correct it everytime it rolls? It might be creating a pilot induced oscillation, although, that is usually thought of as porpoising, but with these polyhedral planes can also be done with rudder...
 
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earthsciteach

Moderator
Moderator
#5
I suspect it is what xuzme is describing. You may be chasing it and overcorrecting. Reducing the amount of travel on the rudder may help this. With a bit of practice, you will get the feel for the right amount of control input.

When you first launch a plane, it naturally tends to roll to the left due to prop and motor torque. If you launch it with the right wing somewhat down (like its rolling to the right), the prop torque will bring the plane up to level, giving you more time to stop the roll with right rudder, if needed.