Flap angles and corresponding stops

[haribole]

Should there be three stops or four stops for the flaps? The main page of the plans shows three flap angles, 15,35 and 50, but the drawing #28 shows five stops including the one for 0 degrees. I am extending my flap handle after struggling to deploy even to the second notch of flaps in my first ever ride from the right side while flying with Rollie. I tried pulling the flap lever with both my hands and managed to deploy it to the second, there is no way I will be able to deploy to the third. On the ground I get full 50 degree deployment with only three notches and noticed that the slots on the 1/8" curved piece had the positions that were not matching with the drawing..

[AZBearhawk272]

Hari

New Comers get all concerned over the flaps.
old timers just fly what you got.
Three or 4 notches will be just fine. The last notch of 50 deg is for real short final once you are fully slowed and committed. It’s truly all drag no lift, kills any float.

First notch I never drop till below 70mph before base turn. Second before final, third notch as needed.

making flap arm longer helps but you need to make sure it is reinforced at the proper places around the slot
pivot arm.

review you flap rigging, having the bellcrank arms off angle where the mechanical leverage is lost will make the flaps difficult too.

The air loads are big.................... slow down..

Kevin D
#272

[whee]

Kevin is spot on. The air loads are huge so slow down.

It is possible that something isn’t quite right. Since you have different notch positions than the rest of us referring to 2nd notch or 3rd notch isn’t very helpful.

Do you have any pictures of the flap quadrant that show the handle, notch positions, and the lever where the cable attaches? Also a picture of arm where the flap cable attaches to the torque tube in the wing root.

[svyolo]

There is no individual step in rigging the flaps that is difficult. Unfortunately there are more variables than fixed values. It is one of the many things that Bob did that does't really have much leeway, including using the oversize thimble at the flap arm. Even then, it still binds slightly.

It has been a while since I did mine, so my memory has faded bit. I do remember starting with have the actuator arm inside the wing resting on the rubber bumper stop, and then measuring the arm that the cable pulls on, as per the plans. I believe mine have 4 notches.

But, at the end of the day like a few others said, what you get is what you get. Nothing is perfect, everything has a tolerance. With plain flaps any more than half is usually more drag than lift, but that drag can come in handy.

After it is rigged, pay particular attention to the triangular plate behind the cargo bulkhead. Watch as tension is taken up, and off. It should be symmetrical. That acts as a bit of a 2D U joint, which sounds nice, but might also hide or cause problems, like a heavy wing.

In particular, I would make sure both flaps are "up" (faired) when both actuating arms are resting against the rubber stops. As you pull tension, the triangular plate should pull symmetrically from both sides.

Sounds easy, but it took me a bit of time.

[robcaldwell]

I must be missing something... Where are the "rubber stops" you are referring to? I'm looking at my flap system from the flap handle all the way to the tensioning springs. Not seeing any rubber stops... Of course I have not mounted my wings to the fuselage yet. Will be doing so soon.

[svyolo]

The flap actuators (inside the wing) rest against the steel support tubes when he flaps are up. In the kit builder manual it mentions putting rubber bumpers on the tubes to keep them from beating each other up and the wearing the paint off.

[rv8bldr]

Here is a pic from Russ Erb's CD showing the rubber bumper on the compression tube.

WA21.JPG

[robcaldwell]

Ok I see it now in the AviPro manual. For some reason I was thinking of a bump stop or something similar. I have mine wrapped in silicone tape which bonds to itself on each wrap. Thanks!

[Battson]

Should there be three stops or four stops for the flaps? The main page of the plans shows three flap angles, 15,35 and 50, but the drawing #28 shows five stops including the one for 0 degrees. I am extending my flap handle after struggling to deploy even to the second notch of flaps in my first ever ride from the right side while flying with Rollie. I tried pulling the flap lever with both my hands and managed to deploy it to the second, there is no way I will be able to deploy to the third. On the ground I get full 50 degree deployment with only three notches and noticed that the slots on the 1/8" curved piece had the positions that were not matching with the drawing..

It is always harder from the right seat, unless you are left-handed.

The first notch on the plans drawing #28 is the home position to leave room for the fuel selector underneath. The second position (15*) is a waste of space, with air loads the flaps don't actually move a meaningful amount.

My normal approach is flaps to 25* at 74kts, 40* at 65kts, and 52* at 55kts. I always use full flaps unless there's a crosswind. Practice makes perfect.

[Nev]

On mine the first two stops are ratchet type, so there’s no need to press the button in. The third and fourth require the button being pressed to exit the detent to increase flap. Is there a reason for this, or could detents be filed to allow the handle to be pulled without depressing the button ?

[Mark Goldberg]

The reason for being able to get those first two notches of flap without pushing the button is how far you have to reach when the flaps are up and the flap handle all the way down. Just for ease of getting those first two notches of flaps when it is a long reach.

I would not do that to the other notches. It could be a bad thing if on approach the flap handle would pop out of a notch and completely retract your flaps. Mark