Flap pushrods and hinge pin.

[Steve Sampson]

I am a day or two from starting to install the flaps. I have two questions:

1. Does the pushrod hole go right through the corner where the side skin meets the bottom skin? A few pictures if anyone has them would be really helpful. I hate to start cutting into that metal!

2. A related question. How do folk secure the flap hinge pin? (I have installed it by drilling a hole through the aileron bracket - on the wing - and had hoped to be able to leave it secured to the bracket, but I have to push it on through in order to be clear of the steel aileron bracket on the aileron, when full up.) Again, pictures would be a huge help.

Thanks,

[pierre smith]

Hi Steve,
On our 6A we cut three hinge pin ears off the middle of the piano hinge that's attached to the wing and two off the flap hinge, corresponding to the ones you have cut off the wing. This will give you a five ear space in the center of the flap. You then make two flap hinge pins, inserted from the middle to the outer flap ends. A 3/8" to 1/2" 90 degree bend in the pins allow you to grab them with a pair of pliers for removal and they don't need safetying since they interfere with each other if either one tries to back out.

The easiest way to find the location for the flap pushrod holes is to temporarily mount the flaps and with them in the raised position, mark a corresponding circle on the fuselage next to the flap pushrod attach point. The hole will be in the side as well as the underside because the stud that attaches the pushrod to the flap has to have a hole in the side of the fuselage to ride up in. If your wings are not mounted yet, you can attach the flap and measure carefully from the rear spar attach point back to the flap pushrod attach point and mark the fuselage. It's easier to have the wings on then you can see exactly where the holes should be.

Regards,

[Dayton Murdock]

Hi Steve
here is a pic of my flap rod hole

[IMG][/IMG]

[IMG][/IMG]

[Steve Sampson]

Pierre/Dayton - with those two posts I have everything I need (for now)! This is really a useful bulletin board even if not many are building -4.

Excellent, thanks,

[Steve Sampson]

Dayton/ Pierre/ Others, I am getting there, but did any of you have problems getting the full "42 to 44" deg movement reccomended by VANS in the build book? I am around the 36 degree mark right now. I have run out of motor travel, and all my dimensions appear to me to be to plan.

I have just noticed on DWG EF4-4 the electric flap diagram (top left) it sais to drill the hole in the EF-401 at 2 3/16th as required. It gives no clue that this relates to the range. If I increased that from 2 3/16th it would all work I think. Thought I would ask first incase there is another gotcha that I have missed. I am just a little concerned because any move exposes the motor to more load.

Thoughts?

Thanks!

[Dayton Murdock]

Steve
What method are you using to measure the angle of travel?

[Steve Sampson]

Dayton, A digital level. It reads very reliably down to .05 deg and is consistent if reversed. I did have this exchange with Gus and I presume that is my answer. What was the dimension on your Dwg., and perhaps more important what did you make it? Thanks.

Seems curious - the copy of EF4-4 I have shows the dim on the EF-
401 as "approx 3". Obviously someone changed it to 2 3/16 for
some reason; my guess is that builders said 3" is too long. 2 3/16 is
too little, apparently. I'd just move the flaps to see what movement is
required at the actuator arm, and drill a new hole accordingly.

Gus

On 26 Feb 07, at 22:35, S Sampson wrote:

> Gus thanks for all that. One more query re the flaps. When I finished
> for today I was having a problem getting the full 44 deg flap movement
> the build book suggests when unloaded. I am probably 10 deg short.
> All the dimensions/geometry are to plan as far as I can see.
>
> However, I have just noticed that at the top LH of Dwg. EF4-4 it sais
> "Approx 2 3/16th as required". Is this an acknowledgement that this
> length will have to be adjusted to get the full movement? If I drill a
> new hole about 3/8th over I would think I will be nearly there.
> Stresses in the system / motor will increase of course.

[Steve Sampson]

I have summmarised the error in the plan here for any future builder who happens this way. I suggest you follow the link BEFORE you start setting up the RV4 flaps. There are two versions of the plans.

[Bob Collins]

[quote=Steve Sampson
1. Does the pushrod hole go right through the corner where the side skin meets the bottom skin? A few pictures if anyone has them would be really helpful. I hate to start cutting into that metal!
[/QUOTE]
This step-by-step might be helpful to you. Or not.