‘67 Citabria 7GCAA restoration/milman spar conversation

[Clifford Daly]

Started a full restoration on my Citabria on 01/13/18 with the end goal of..... OSHKOSH! Fuselage is finished through silver and back out at the airport.

 

[Clifford Daly]

The dreaded spar conversion was next.... I was told it couldn’t be done but the left wing went from covered to ready for fabric in 1.5 weeks and a total of 67 hours. This included the full tear down, painting all attachments, replacing any necessary hardware, and putting it all back together with the new spars.

I’ll do a more detailed progress on the right wing when it comes into the shop next week!

 

[JimParker256]

Wow! That's looking good, Clifford. Ambitious to try to be ready for OSH, but given your progress thus far, you'll probably make it with time to spare!

Or was the "end goal of... Oshkosh" said in the same vein as my answer to the "When will your Bearhawk Patrol be finished?" My answer is always "Tuesday. Not sure WHICH Tuesday, but it will be Tuesday."

 

[aftCG]

Thanks for sharing your project. How were your internal bracing wires? Did you find any cracked ribs or anything that set you back?

 

[Clifford Daly]

Wow! That's looking good, Clifford. Ambitious to try to be ready for OSH, but given your progress thus far, you'll probably make it with time to spare!

Or was the "end goal of... Oshkosh" said in the same vein as my answer to the "When will your Bearhawk Patrol be finished?" My answer is always "Tuesday. Not sure WHICH Tuesday, but it will be Tuesday."

Hahah cant be wrong saying it’ll be done on Tuesday! It’s very ambitious so I won’t be upset if it doesn’t work out but fingers still crossed!

 

[Clifford Daly]

Thanks for sharing your project. How were your internal bracing wires? Did you find any cracked ribs or anything that set you back?

Wing was sound! It hurt taking something apart that was perfectly good but I knew I’d be mad if I didn’t do it now. Bracing wires were all good and no visible cracks. I was lucky with the first wing but still haven’t took the fabric off the right wing..

 

[Bartman]

Thanks for posting your project Clifford! Did you have any experience doing this kind of work before you started? I'm wondering if a fuselage project could be done in one winter by a relative novice.

Did your new spars slide right in? I expected them to slide in but ended up having to brace the ribs and anchor everything to the table so the spars could be tapped in with a wood block and mallet.

Thanks, looks great!

 

[Bartman]

@Clifford Daly Did the holes in your aileron cove material line up exactly with the holes in the ailerons when you were putting the first wing back together? Mine aren't lining up....

 

[Clifford Daly]

Did your new spars slide right in? I expected them to slide in but ended up having to brace the ribs and anchor everything to the table so the spars could be tapped in with a wood block and mallet.

I used two others help to slide them in just to watch them and give a little extra push if needed. It was only a few ribs that would prevent it from going on. I also had to use the file method for the front spar.

 

[Clifford Daly]

@Clifford Daly Did the holes in your aileron cove material line up exactly with the holes in the ailerons when you were putting the first wing back together? Mine aren't lining up....

Can you post a picture with what you’re talking about? The hinges went on smoothly and the aileron went on fine when I tested it.

 

[Bartman]

Can you post a picture with what you’re talking about? The hinges went on smoothly and the aileron went on fine when I tested it.

I had a couple of ribs that were off a little from the original positioning. My IA said to go ahead and drill new holes.



I'll check the spacing of the old wing and the new spars before I disassemble the left wing panel next week. I consider your 10 day wing panel conversion mark as a challenge!

 

[Bartman]

I used two others help to slide them in just to watch them and give a little extra push if needed. It was only a few ribs that would prevent it from going on. I also had to use the file method for the front spar.

I had to file mine too. Don't have a picture of all of the bracing needed to tap in it while working by myself. Will take one next time.

 

[Bartman]

I had a couple of ribs that were off a little from the original positioning. My IA said to go ahead and drill new holes.

View attachment 753

I'll check the spacing of the old wing and the new spars before I disassemble the left wing panel next week. I consider your 10 day wing panel conversion mark as a challenge!

I spoke with Mike from Milman Engineering yesterday, he said it isn't unusual to have ribs positions off by as much as half an inch between the new and old spars. The new aluminum spars are drilled in a master jig so they're consistent from one set to the next. He figured on any given day back at the old Champion factory, depending on who was laying out a set of wings, there might be variation due to it be done manually by human labor.

So there you go.

 

[Clifford Daly]

Yeah that’s what I was thinking because some were perfect and others were just slightly off. When I looked at the new wooden spars, only the holes for fittings are drilled. So it’s all a trusty ruler for the ribs!

 

[Bartman]

@Clifford Daly did you use Vaseline under the leading edge sections when you were fitting them like Milman suggested? Did you install the STC leading edges?

 

[Clifford Daly]

@Clifford Daly did you use Vaseline under the leading edge sections when you were fitting them like Milman suggested? Did you install the STC leading edges?

I actually used the original leading edges. They were replaced on the last recover and looked brand new. Do the new leading edges call for Vaseline for the purpose of not scratching the spars? That’s interesting.

 

[Bartman]

They recommend vaseline for the initial fitting of the leading edges, to help them to pull tight onto the ribs. after they're fitted and the holes are all drilled, the panels are to be removed and the vaseline cleaned off before putting the panels on for good.

I got the first leading edge panel on and the tank all installed and the area trammeled so we're moving along again. Thanks for the reply.

 

[Clifford Daly]

Awesome news! The second wing is going to fly by for you, I got my second one done in half the amount of time and with no questions.

That’s a neat idea with Vaseline. Does it come off easily? I feel like it could make a mess

 

[JimParker256]

Kind of reminds me of the learning curve building the landing gear oleo struts for my Bearhawk Patrol homebuilt... Took me about 18 hours (over 2 1/2 days) to assemble the first one. The second one went together in about 2 hours... It's all in the technique!

 

[Clifford Daly]

And just like that, the spars are finished and the wings are covered! I also added the interior since it’s just too good not to show off! The past few days have involved spraying poly brush and poly spray. The left wing is ready to sand and the right wing will be in silver this afternoon.

I cut the fabric off the first wing on April 14th so it took just over 7 weeks for both wings to be thru silver. BUT I have committed my life to it and have worked 6-7 hours a day from when I get home from work until bed.