Re: Wing Spars Fairchild 24W40
Posted: Sat Jul 04, 2015 4:58 pm
' After many years of buying Sitka, finally I won't buy spar material that I've not inspected myself first. This is the most difficult issue with rebuilding wood wings - finding quality spar material. Even prominent aircraft suppliers will sometimes ship wood that I would only cut up for cap strips. It's hit or miss, mostly miss, in recent times if you're picky about spar material which I am. Last time I ordered spar material sight unseen from a prominent aircraft supplier, out of 4 spars I was able to use 2. The other 2 got cut up. You would think they understand aircraft requirements, being an aircraft supplier! I'm not expecting more than AC43.13 requirements but I won't accept less either. Actually, that's not true - I do expect better than 45 degree vertical grain, which is all AC43.13 requires. More like 75-80 degree minimum vertical which I specify in advance. But in all other respects AC43.13 is adequate IMO. And with the cost of shipping, you can't send it back! The way to do it is to go there and select what you buy. If you're not experienced regarding how to select, bring someone who is. I would definitely not leave this to a lumber yard to select spars. In my experience, it is extremely unlikely you'd get what you need for aircraft spars...though you could get lucky...
Thanks for listening - needed to get that off my chest! haha.
David
On 7/4/2015 2:51 PM, Andrew Budek-Schmeisser tempusfugit02@gmail.com [fairchildclub] wrote:
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Thanks for listening - needed to get that off my chest! haha.
David
On 7/4/2015 2:51 PM, Andrew Budek-Schmeisser tempusfugit02@gmail.com [fairchildclub] wrote:
In regard to using DF, keep in mind that AC43.13 does allow spars to
be laminated, either vertically or horizontally. Finding a good
single-piece blank of DF is tough, but smaller pieces that can be
laminated present less of a problem.
Russ Harmuth uses DF in his full-size Spitfire replica (Allison
powered), and I believe he sourced his lumber from Southern Lumber in
San Jose, CA. I've talked with them; they seem to understand the
requirement for good CVG (clear vertical grain) pieces.
On 7/4/15, Hans Friedebach hans@tsoproducts.com [fairchildclub]
fairchildclub@yahoogroups.com wrote:
> Mike,
> Doug Fir is an FAA accepted and less expensive alternate to Sitka Spruce.
> The drawback is twofold
>
> · it likes to split and splinter and is not as easy to work with as
> Sitka Spruce.
>
> · Weighs more than Sitka Spruce – useful load penalty especially for
> an airplane that is not generously set with useful load to begin with. But
> run the math yourself and figure how many pounds and what percentage of
> useful load it will cost you.
>
> I don’t believe you are likely to see a difference in resale price with Doug
> Fir Spars – most buyers don’t drill down to that level of technical detail
> unless something raises a flag. I have never had a prospective buyer ask
> about useful load on any vintage airplane I have sold.
>
>
> Ask Mike Kelly about his experience building F24 wings and what he advises.
> I know that Marc Stamsta (262) 490-8451
> www.maxaero.net Hartford, Municipal Airport KHXF in
> Wisconsin uses Doug Fir for HOWARD DGA spars (a bit more flexibility with
> useful load on those) He also builds Fairchild wing kits. One way to dodge
> the workability issue is to let someone who does it all the time do it for
> you.
>
> Hans
>
>
>
>
> From: fairchildclub@yahoogroups.com [fairchildclub@yahoogroups.com]
> Sent: Saturday, July 04, 2015 2:02 PM
> To: fairchildclub@yahoogroups.com
> Subject: Re: [fairchildclub] Re: Wing Spars Fairchild 24W40
>
>
> Hans,
>
> I have talked with a couple people who have gone with new douglas fir spars
> instead of sitka spruce. They said this only adds two pounds per wing and
> more strength than spruce. What is your opinion and how do you think this
> would effect the value/resale of the plane?
>
> Thanks,
> Mike
>
> Sent from my iPad
>
> On Jul 4, 2015, at 11:22, Hans Friedebach
> hans@tsoproducts.comhans@tsoproducts.com [fairchildclub]
>
> wrote:
>
> Additional comment re: Michael Thomas original spar use
> My earlier comments were aimed at the airworthiness determination question.
>
> Reflecting on the forum thread, I realize that the issue really goes beyond
> airworthiness into the economics. If Mike has spars lying on the bench that
> means the wings have been totally disassembled. At that stage there is so
> much labor required to build up a set of airworthy wings that the end result
> would not justify the effort and expense. Mike would have at best an
> airworthy “old” wing. Considering the total investment in the finished
> airplane, my sense is that the resale value and re-sale-ability of the
> airplane would suffer more than the cost of using new(though expensive) spar
> stock.
>
> Bottom line:
> although I arrive at the same conclusion, but for a different reason than
> Dave@ranchaero, I would also go for new Sitka Spruce Spars.
> And yes, the old spars can fly once more as braces for new ribs. I’m doing
> that right now with some old retired Stearman spars.
>
> After more than 30 years of buying and selling vintage airplanes I find that
> the “Best” airplane is the most saleable. Not just a question of how much
> you get for it, but can you find anyone with the money. The people who have
> both the desire AND the money will go for the “Best”. Until that day the
> restorer has the enjoyment and satisfaction of having and enjoying the
> “Best”, too, even if it is not done on the basis of economics alone.
>
> Thanks for letting me share these thoughts with you all.
>
> Hans
> From: fairchildclub@yahoogroups.comfairchildclub@yahoogroups.com
> [fairchildclub@yahoogroups.com]
> Sent: Saturday, July 04, 2015 10:00 AM
> To: fairchildclub@yahoogroups.comfairchildclub@yahoogroups.com
> Subject: Re: [fairchildclub] Re: Wing Spars Fairchild 24W40
>
>
>
> This group is a gold mine of information.
>
>
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