Sign in to follow this  
Followers 0

Avid C HH wing build 101

126 posts in this topic

Posted (edited)

Yessir, 35 1/2" c-c! On the intial glue, there are only 2 long ribs to be glued. The remaining 3 are 2 trailing edge ribs behind the tank and the tip rib. It's gonna be critical to get these first ones right! Also, there are 3/32" holes drilled in the left wing spars. These were drilled for a drag tube that won't go there, the fuel tank goes there instead. Guess they kinda missed that! Any ideas what to do about those holes. I was gonna put rivets in 'em, but a friend said that they may rub a hole in the tank.  He said JB weld, but I'm thinkin'........Ideas?

Wyatt

Edited by 3CW
Wanted to add. Went flyin' in the Challenger, beautiful, but rougher than a cob!

Share this post


Link to post
Share on other sites

Posted

I don't know how the Avid tanks fit, but on my Kitfox tanks they fit loose enough that you are supposed to put some GE Silicone II between the spars and the tanks, so rivets put in the holes would not be rubbing the tank.   EDMO

Share this post


Link to post
Share on other sites

Posted

Yessir, 35 1/2" c-c! On the intial glue, there are only 2 long ribs to be glued. The remaining 3 are 2 trailing edge ribs behind the tank and the tip rib. It's gonna be critical to get these first ones right! Also, there are 3/32" holes drilled in the left wing spars. These were drilled for a drag tube that won't go there, the fuel tank goes there instead. Guess they kinda missed that! Any ideas what to do about those holes. I was gonna put rivets in 'em, but a friend said that they may rub a hole in the tank.  He said JB weld, but I'm thinkin'........Ideas?

Wyatt

I agree with ED, SS Rivit there should be plenty of clearance

Share this post


Link to post
Share on other sites

Posted

Howdy boys! 

I was gone, but now I'm back at it! Have the ribs glued to the spars with a 3/4" washout and have the strut attachments fit. 80" center of the bolt holes to the root end of the spars. I also have the fuselage attachment elevated above the spars 36" c-c. Boys, I got to tell you, I'm gunny about pokin' the holes in the spars! Those are the only measurements that I have. Is there anything else I would need to check? I have the attachments held in place with hose clamps and have 1/4" of thread showin' at the rod end. I really wish the other strut had adjustment too.

Tomorrow, I figure on setting up the spar stiffeners with 4 pieces of 1/4"X 3/4" birch plywood to make an"I" beam. What would be easiest way to profile the stiffener to fit the I.D. of the spar? I'll be using Poly-Fiber epoxy varnish for a sealer. The way I see it, the only thing that holds the stiffener in place are the rivets from the spar attachment. Ain't a lot, but I guess it's enough. 

Well, that's enough to keep me busy for a bit! 

Keep me straight!

Wyatt

About forgot! Can I buy a mounting for my wing tip position light or would I have to make it?

image.jpeg

image.jpeg

image.jpeg

image.jpeg

Share this post


Link to post
Share on other sites

Posted (edited)

Kitfox sells the light mount and you can make it work on the Avid tips.  I've got a new set I would sell for $20 plus shipping.  EDMO

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted (edited)

Otherwise you can cut a small piece of aluminum slightly bigger than your light then sand a flat spot on your wing tip, and glue the aluminum onto the wing tip, then fill the edges in with hysol and shape it into the wingtip,

and nice work keep it up

Edited by TJay
1 person likes this

Share this post


Link to post
Share on other sites

Posted

Hey Ed!

SOLD! PM me your address 'n I'll send the money!

Wyatt

Share this post


Link to post
Share on other sites

Posted

Wyatt,

Mailed today 6 April - got tracking number too.

EdMO

Share this post


Link to post
Share on other sites

Posted

Thanks Ed! Put the check in the box, but the mailman must've come early. Oh yeah! Checks in the mail! 

Beefed up the spar stiffeners today. Take note of the clamps. Thanks JimChuk! I'll be workin' on fittin' them in the spars. The plan is to use a sanding pad on a grinder and just go slow. Any other ideas would be appreciated! Looks like a long process to me.

Wyatt

image.jpeg

Share this post


Link to post
Share on other sites

Posted (edited)

Wyatt,  One of the Avid builders I watched took a piece of 3/4" conduit and taped a rag to the end of it - gobbed some 9460 on it and CAREFULLY put it in the top and bottom areas inside the spar and swabbed the glue in the right area before inserting his plywood insert.  I am not a fan of the plywood inserts, so I bought some 5 foot long extruded aluminum I-beam inserts from Just Aircraft in case I build more wings.  They are like the Kitfox inserts, only cheaper. 

In case you haven't thought of it, some epoxy spar varnish on the inserts will protect them, just like protecting the ribs.   EDMO

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted

Ed, would you do me a favor and post a picture of those aluminum stiffeners? If I don't like the result with the wooden stiffeners, I would like to have the option of using the aluminum. Contingency! 

Wyatt

Share this post


Link to post
Share on other sites

Posted (edited)

Wyatt,  I don't have a picture to post, but someone posted a picture of one.  There is also Kitfox drawings in Files and Forms of the reinforcement that the UK mandated.  One was just some aluminum the shape of the rib from rear spar to tail tip and bend a 1/2" angle on it where it goes under the ribcap and glue to both sides and rivet it to the rib and tail back to just before the hanger bolts go thru the tail.  I don't agree with rivets shown thru the rib cap.  The UK showed .025 aluminum, I think, but mine are lots thicker because I have more powerful 15" chord flaps and ailerons.  EDMO 

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted (edited)

Ed - I think Wyatt was inquiring about the aluminum I-Beam spar stiffener extrusion, not the rib reinforcements. As I understand, the aluminum extrusion can be sourced thru Kitfox Aircraft or Just Aircraft (less expensive), however, they only fit the .065" wall, not .083", spar tubes.

image.jpeg

Edited by dholly
Pic

Share this post


Link to post
Share on other sites

Posted (edited)

Ed - I think Wyatt was inquiring about the aluminum I-Beam spar stiffener extrusion, not the rib reinforcements. As I understand, the aluminum extrusion can be sourced thru Kitfox Aircraft or Just Aircraft (less expensive), however, they only fit the .065" wall, not .083", spar tubes.

image.jpeg

Thanks for the correction Doug.  TJay used the Just stiffeners (inserts) in his .083 wall spars - just have to take about .018 off of each side, or .036 off of one side - I don't know which way he cut it down enough to fit.   These are 5 feet long about 10 times better, IMO.   I have a set if you cant get them anywhere else less than $300 for 4 of them.   EDMO

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted (edited)

Hi guys!

Feel like I got a good fit on the spar stiffeners. I used the table saw like a planer to true them straight, and shaving them down to the height that was slightly taller than the I.D. of the spar. Then I set the blade to a 10 degree angle and ran them down the 4 corners. Just shaving the stiffeners left burn marks on them. When I sanded out the marks out and tried them, they fit perfectly. Now I'm going to varnish them with Poly-Fiber epoxy varnish. I know, after varnishing, I'm gonna have to do some more sanding since I've got such a good fit without. How many coats would I want on the stiffeners, and the ribs too for all that matter? Another question: Is there any kinda of lube I could use to slide them in place? It just takes time!

,Like I said, I'm gun-shy about drilling the rivet holes for the strut attachments on the spars. I'm thinkini' that I'm gonna leave the attachments hose clamped, attach the wings to the fuselage and drill/cleco the holes in place. I feel like this would insure their exact location. Am I nuts?

image.jpeg

image.jpeg

Edited by 3CW
Forgot pics

Share this post


Link to post
Share on other sites

Posted

Use baby oil on the aluminum ones, with wood just push harder, And hose clamp the attach bracket on then drill after the wings are rigged,

Share this post


Link to post
Share on other sites

Posted

Thanks TJ! I thought that might be the best way.

Wyatt

Share this post


Link to post
Share on other sites

Posted (edited)

I would say to try some liquid floor wax - it wont hurt your inserts or struts.  EDMO

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted

Hi guys! Gonna get back to work on the wings after a long absence. We’ve relocated the project.  How do you guys feel about the fiberglass fuel tanks? Issues?

Wyatt

Share this post


Link to post
Share on other sites

Posted

Hi guys! Gonna get back to work on the wings after a long absence. We’ve relocated the project.  How do you guys feel about the fiberglass fuel tanks? Issues?

Wyatt

There are ethanol capable fiberglass tanks, I have them. Much better than aluminum wing tanks, which are reported to not flex and therefore cause tank cracks.

Share this post


Link to post
Share on other sites

Posted

I think I  would maybe slosh them with KBS coating gas tank sealer.  That would help to protect them from leaking.  It will cost maybe $75 or so, but may buy some peace of mind on them leaking at some later date.  Easier to do it now before they are in the wings, although that is fully possible as well.  JImChuk

Share this post


Link to post
Share on other sites

Posted

Aeropoxy seems to be the best epoxy for fuel tanks.  I have Cozy plans, and hang out on the Cozy forum as well.  All reports of Aeropoxy used in the fuel tanks are positive.  On user did a coupon test with various epoxies.  Most worked fine, but Aeropoxy held up a year in a bottle of E-85.

Mark

 

Share this post


Link to post
Share on other sites

Posted

Howdy guys!

Decided not to coat the tanks. They tested fine.

I have a couple of questions:

1st: To secure the wooden spar stiffener, do you reach inside the spar with epoxy on a stick or just depend on the rivets on the centerline of the strut attachment.

2nd: How can you pop the rivet behind the clip on the strut attachments?

Wyatt

Share this post


Link to post
Share on other sites

Posted

Hey guys,

I was hoping to hear from someone in regard to my questions of applying glue to the stiffeners or not. In my opinion, for what that’s worth, I don’ feel they can move when the strut attachment is riveted. I do have a good snug fit on the inside of the spars. The instructions say nothing about glueing them. Ed did mention it though. Also, I haven’t figured out how to get that rivet under the clip. Can’t get the rivet gun in there to pop the rivet. 

With the spar attachments clecoed in place, I did go ahead connected the wings to the fuselage. Plumb bobs/string line on the leading edge and triangulation from the tips to the tail prove I got a good result. I did this with the wing tanks in place on a dry fit. When glueing the ribs to the spars the washout was set to 3/4”. It was mentioned that the tanks were made with a twist to allow for washout. They do. At the time, didn’t think it would be a problem, but the spars do have a bind. Not bad, but a bind. The left strut was made at the factory to be adjustable and the right was not. I did modify the right strut to match. The adjustment will hold the bind, but to relieve it somewhat, the washout will increase to a 1 1/4”, the book called for 2”. I am pretty sure I’ll have to modify the jury struts too.

I’m heading out to clean the fuel tanks with 1 gal acetone:1 gal AV gas. After sloshing it around we’ll leak check and further flush by filling them up with fuel. 

I would appreciate guidance anyone can offer.

Wyatt

 

E819B0F7-314A-4A74-8B1B-E6780E20502F.jpeg

AA3A4B52-F202-4B67-94AB-D822AD2DB872.jpeg

90454EE6-45CB-45C9-B2A5-28998F5C19D6.jpeg

C79C07FD-D04E-4100-92B6-9EF7AB9762B8.jpeg

Share this post


Link to post
Share on other sites

Posted

Hey Wyatt,

your 'impossible ' rivet install may be solved by installing an aircraft grade Jo bolt. Below you'll find a video to show you how they are installed. The principle is the same as a pop rivet but instead of just pulling a shaft through the rivet body, the Jo Bolt uses a threaded shaft and a disposable nut (breaks when pull pressure is obtained). In the video they show you the install using a tool (no space for you) but I have installed Jo bolts with success using two spanners (one holding the nut and one turning the threaded shaft until it breaks). It is a bit slow to install in a tight place but I am sure it would work on your strut fitting .. The Jo bolts are much stronger than pop rivets.

 

1 person likes this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0