Making new spars for a 7BCM

[David Johnson]

Tim, I think my drill bit wandered a little. I will use your brad point bit next time to help stay straighter. Thanks, David J.

[s35pilot]

These are the spars after I finished the trird coat, I was real pleased with the the finish

Well, I'm back and here is where I'am with the project. It has been a long time since I posted, got tied up with work and other commitments.
After finishing the spars, I ordered 15 new ribs for both wing rib replacement, they were damaged beyond repair. I cleaned up the old ribs and all the other wing parts and primered them with a 2 part epoxy primer. I ordered all new AN hardware to reassemble the wings.

Here I'm working on the (R) wing.


I remember reading in one of the blogs about making a template of the fuselage wing mounting brackets for correct spacing. I welded 3/4" square tubing to a piece of 1 1/2 anle iron and drilled them for the wing attach bolts.
I then layed out and trammeled the wing with the help of a buddy who has had a lot of experience ( he has a banner towing business with 12 Scout's on line and has rebuild all the wings, matter of fact he is going to show me the covering process when I'm ready) I did not take any photo's of trammeling on this wing but, I will on the other side.

after the trammeling was complete (Oh, by the way....it took about an 1 hr)
I nailed all the ribs in place with nails I ordered from Wag Aero (they are 3/4" 14 ga. ring shank nails) I needed to grind about a 1/16" off the tip keep from going out the back side, it only took about an hour to do all that was required.

This is waht I used.

I used a tack hammer and an alum. 3/8" rod to set the nails (worked great)

I waited 2 months for the stiffener I ordered from Wag Aero but, was told it was still on back order as of Nov. 25 so I called and Univaire had it in stock. It is a 2 piece T alum. I talked with my IA and asked if it would be ok to flush rivet the stiffener in place, he had no problem wit it so, that's what I did. Here you will see the stiffener joint with flush rivets.
Then I riveted all the top side of the stiffener to the ribs, this way I can line up all the screws to attach the leading edge to the lower part of the stiffener and ribs all together.

This is a shot of the tip bow installed.

[joea]

Really wish that you would clean up the shop a bit more! I can see one spot on the floor over by the parts washer!

Boy, excellent work and your documentation is excellent as well. Cannot wait to see the rest of the airplane if the wings are this beautiful!

Thanks for posting this, was wondering how things were going. Life does get in the way of restoring planes at times but with yours it was worth the wait!

Joe A

[s35pilot]

Hi Joe, Thanks....I will post the progress. It will probably slow a bit again with the holidays but, I just keep plugging along. Here are a few more photo's I ran out of time to post the other night.

A shot of the stiffener after riveting in place.

In order for the stiffener to reach to the tip rib (and be riveted), I had to put that 1/4" space in the stiffener that you saw in the photo of the stiffener joint. I also, used 8/32 mechine screws to hold all the dia. braces in place.

Just a shot of the but rib attachment

[CptKelly]

I didn't know the 7 series had a tube wing tip bow??? Is this original?
Absolutely beautiful work. Those wings will last another 60 years.

Mike

[s35pilot]

Hi Mike, as far as I know, the 7 series has the tube tip bow........these are the original tips that I removed for restoration. I flew to Santa Paula today (it's a small airport up in the valley outside Los Angeles that host an antique fly-in once a month, I believe, they do it more for all the aircraft owners that reside there, they can be exempt from paying taxes on their aircraft if they show them) well, anyway I meet a guy working on a Champ, I was talking with him and paying close attention to his wings, they appeared to have the same tip bows.

[Nathan K. Hammond]

Tim's correct; both the 7 and 11 series used a metal tube for the bow. They finally did away with it on the 7EC I think; when the company switched to FiberGlass tips.

nkh

[Rafael]

Hi Tim:
I live in Lakewood, down wind 25R for KLGB and Im restoring a 38 Chief and also a 46 11ac. Need to make spars for both and would love to see your project and exchange info. Could you please email me?
Tks
Rafael
botijo@verizon.net

[joea]

Tim,

Hope you can get ahold of Rafael. I first met him at the Aeronca factory fly-in years ago in Middletown, and he is a real Aeronca person.

Right now he is restoring two Chief's from the ground up, including very difficult surgery to the metal tubing in the fuselage.

Joe A

[s35pilot]

Rafael,

You bet, I will be at the Hangar tonight (eagle aviation) my cell # is 562-756-1158 and email me at k35bear@aol.com

[SFC Hiatt]

Make sure you take your shoes off before going into his shop. Pictures make his place look like a hospital and his work looks like the work of a surgeon.

[s35pilot]

Hi Joe,

I did meet with Rafael tonight, found out we live about a 1/2 mile from each other,very nice guy, I'm looking forward to see his projects.

I would like to share an email I recieved from Rainbowron this afternoon. I would like to hear what other have to say about this topic, primarily the adhesive concern.

Sir; I hope I am reaching the right person here. I viewed your post on building spars. I build PMA spars for Champs and Citabrias. See my home page at www.rainbowflying.com. I have two comments on your spar building. One is that the FAA is not very accepting of epoxy glue. I use resorcinol glue, the two part kind. The other thing is the forestner bits. While they make a good hole I have found that they make oversize holes. rainbowron

Hi Ron,

You did reach the right guy and first off, I hope you understand I'm not trying to take any business from you or any other spar builder. I built mine because, I wanted the experience, nothing more.
In my research to build the spars, I found several restorers that were using and recommending the T-88 2 part epoxy. If you know a specific problem with it, would you advise me. As for the forstner bits, my bushings fit very snug, especially after varnishing the holes. If I was to do this again, what bits would you recommend?

Thanks you, Tim Harvey

I showed the process to my IA and we both read AC 43-13 concerning adhesive and believe this to be an acceptable process.

[joea]

Tim,

In the end, there are two people who have to be satisfied with your work, yourself and your IA.

You might mention it to your IA and see how he feels and do some research on it yourself.

Glad you and Rafael got in touch and live so close. Its a small world at times!

Joe

[Nathan K. Hammond]

I completely agree with Joe; only you and the IA need to be satisfied. If the IA approves something, end of discussion; he was given the authority to approve/deny/defer by the FAA.

Many of the local restoration shops and old timers are using T-88 these days. A couple of them made up bunches and bunches of little test strips and subjected them too all kinds of abuse for their own piece of mind; hot, cold, submerged, boiled etc... None failed. The locacl FSDO (ATL) doesn't have a problem with it either, probably because there are so many antique/classic in the ATL area or they have common sence.

nkh

[N3840E]

I like and use T 88 and see no problem as well. In regard to the forstner bits they are like a lot of tooling available, they are subject to size variance's like any other tooling on the market. I have some real cheap chinese bits that are for hogging on non aviation projects and some well made european bits that are clearly better made by just holding them up together and comparing them side by side. Nothing wrong with resorcinol either but it is harder to work with. One of my favorite glues is Hughes FPL16A but it is also a pain to mix and work with. Great work on those wings S35 pilot.