Static/mass balanced or not

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

autoreply

Well-Known Member
Joined
Jul 7, 2009
Messages
10,748
Location
Rotterdam, Netherlands
Flew some aricrafts with negative positions. How did you find that effect changes in terms of speed? I always thought and found that at HIGHER speeds they require MORE force to pull them into neutral positive, while -7, -5 degrees (up) goes a EASIER, not vice versa, that was my point.
Speed (q) determines the absolute forces, but not the direction. That's the aoa, Cl and thus the wing loading.

Indeed, we both noticed that flaps that can move freely move up. That's why flaps that can't (on most aircraft) won't flutter, because flutter requires freedom to move both ways.
Also, why is there a Vfe speed? Why you are more likely to break them at higher speeds?
It's the spar/wing. Lowering the flaps lowers stall speed. That also lowers the speed at which you can pull 3.8, or 4.2 G, plus it increases the magnitude of gusts. They also add a lot of torsion in the wing, which - especially at high speeds - is very unwelcome.
 

David36

Active Member
Joined
Dec 19, 2012
Messages
31
Location
UK
Speed (q) determines the absolute forces, but not the direction. That's the aoa, Cl and thus the wing loading.

Indeed, we both noticed that flaps that can move freely move up. That's why flaps that can't (on most aircraft) won't flutter, because flutter requires freedom to move both ways.
I sent you a PM, however, decided to continue here to have more opinions. What makes the direction to be different when talking about flaps and not about ailerons? They same to be affected by the same conditions.

It's the spar/wing. Lowering the flaps lowers stall speed. That also lowers the speed at which you can pull 3.8, or 4.2 G, plus it increases the magnitude of gusts. They also add a lot of torsion in the wing, which - especially at high speeds - is very unwelcome.
You mean exceeding Vfe won't brake the flaps due to high airspeed airflow pushing flaps upwards? I always thought that. This seems different than what I was taught in training and from what I heard everywhere
 

Dana

Super Moderator
Staff member
Joined
Apr 3, 2007
Messages
9,200
Location
CT, USA
You mean exceeding Vfe won't brake the flaps due to high airspeed airflow pushing flaps upwards? I always thought that. This seems different than what I was taught in training and from what I heard everywhere
It could be that too... it's whatever the weakest link is.

-Dana

Blow your mind, smoke gunpowder.
 
Top