Flaps, Alerons, Flaperons

[Bennie Vorster]

Please explain the difference to me. My BB is fitted with flaperons.

It seems like the guys sort of adjust the control for it parallel to the floor board and forget about it. What is the use then?

When I lift the controls, it seems to lift or drop the flaps on one side more than the other side.

What will happen if you are taking off and this control lever adjust by itself or a pax step on it?

[justin.schoeman]

Flaps = aerodynamic device for increasing the effective angle of incidence of the wing. Provides more lift at higher drag, allowing you to fly more slowly.

Aileron = aerodynamic device for increasing and decreasing the effective angle of incidence of each wing, thereby inducing roll.

Flaperon = combination of the two. The 'ailerons' work as normal, but the flap lever moves them both down simultaneously - having the same effect as flaps.

On the BB, the couterweights of the ailerons extend so far forward that if you take full flap, you will not have much aileron control (the couterweights press up against the underside of the wing). This can catch out the unwary, so many BB pilots just ignore the flaps, and land a little faster.

If it adjusts itself during flight, something is very wrong. Fix it. If a pax adjusts it during flight (or plays with any aerodynamic controls without your permission), open the door, and boot them out .

-justin

[KFA]

[Rudix]

When I lift the controls, it seems to lift or drop the flaps on one side more than the other side.

Hi Bennie,

Justin is 100% correct, just one point from me.

When you drop/raise the flaps they MUST move equal amounts or there is something wrong ! If they do not it will cause the plane to roll and that would not be fun.

I would be surprised if the do not move an equal amount, the way the BB "mixes" the flap/aileron should not allow this, if it does you should find that the ailerons also moves un-equal amounts.

Does the plane want to roll when you drop the flaps in the air?

Hope you will be flying again soon

Regards,
Rudi

[Mogas]

Hi Bennie
Further to what Justin says, I have modified my flaperon system in the following way to make it safer, more user friendly and to fully utilize the STOL capability of the tail dragger BB.
I also did not like the way the flap handle sits close to the floor when flaps up so I cut it just past where it crosses the torque tube between the joysticks. Then I bent a nice goose neck out of the same grade of steel tube and welded it on, Now the flap handle is right near where I need it, just below my throttle control and I don't have to fumble around for it on the floor.
To give me more flap travel and also have aleron travel at full flap I have modified the horn balance on each aleron as follows. First I made aerodynamic shapes out of some flat steel sheet then welded a short piece of pipe on each. these pieces of pipe are angled to give the same angle of incidence as the flaperon. Then I filled these with molten lead. The finished product is about 1/3 heavier than the standard hammers that come with the kit. Next I cut the arms on the flaperons much shorter, used some aluminium pipe of a slightly larger diameter than the arm and trimmed it down till I got the flaperons balanced IAW the manual.
I then adjusted my up elevator travel to max to assure elevator authority on roundout.
The end result is 23degrees of flap with full aleron travel and my plane stalls at 25 kts full flap at max weight 500kgs.
I am not able to give you any measurements as I am not near my plane at the moment.
Here are 2 pics of the system.

[GR8-DAD]

Mogas, do you land with flaps? I normally come in with no flaps at 70mph.

Bennie, if you are stationary and lift the flaperons and the stick is not deadcentre, it will create the impression that it lifts/drops the one side more than the other, but it's not. Looks like that with the eye cause the ailerons are at opposing angels In flight you can use the flaperons lever to trim for straight and level flight, climb trim, etc. Small adjustments are normally more than adequate.

[Mogas]

Mogas, do you land with flaps? I normally come in with no flaps at 70mph.

Ja, I always land with at least some flap. I my base turn min 60kts no flap, 50kts 1/3 flap and 45kts over the fence.
If no Xwind to worry about I often practice short field, 3 point full stop landings. 1 up I can stop in about 100m, even with the crap drum brakes I have.