BC12 Front Spar

[taylorukuk]

Hi

Looking to replace my BC12D front spar - Are the dimensions 3/4" thick (tolerance +1/32" - 0) x 5 11/16" deep?

Has anyone replaced a front spar / any tips and hints?

BR Ian

[Clark]

Have you tried "Search," function yet? I have been referring to that as I have to replace two of my spars and possibly a complete third one but hopefully only replace a section.

[taylorukuk]

Yes I have used it but it didnt return much..

[astjp2]

You can buy a spar that is built from wag aero for much less than you can get the materials and your time. Good luck with your project. Also install the bushings while you have it apart. Worth every penny and time required.

[taylorukuk]

We looked at the WAG Aero option but they were not really interested in sending it to the UK and final price for a front spar was approaching $2500 delivered ($900 on the website)

[N96337]

Try www.bigskystearman.com
Great people and wood!!
John

[n6346m]

I have a very good serviceable spar that I can sell. It's located in Seattle. If you're interested I can try to find out how much it will cost to ship it.

Bob Picard

[taylorukuk]

Thanks for the offer but I think the postage to the UK is just too prohibitive at the minute...

[3Dreaming]

Do you have your old spar? Use it for patterns and dimension.

[taylorukuk]

Yes - I have measured them (we have 3 unserviceable ones) - dimensions are as I thought and we will use them to drill the new holes.

[Bruce Caldwell]

I used Big Sky Stearman as well. Great people and product!

[taylorukuk]

Just trying to source some douglas fir for our spar - Was the original front spar supposed to be 1 piece of wood?

(all our scrap ones are made from bits and pieces probably due to shortage of quality wood in 1946) however was that intentional or should they really be 1 piece?

[Hank Jarrett]

Taylorcraft spars were made by the same company as some higher end planes and they were made by laminating strips trimmed from other planes blanks after the war. When tests were done (because as might be understood, some felt this would result in a lower quality spar) it was found the laminated spars were STRONGER than a single piece! We now know that laminated wood IS actually stronger since any flaws in a single strip that might not be caught would only impact that single strip and the chances of more than one flaw lining up were very small (unlike in a single piece spar where a flaw was pretty much guaranteed to cross the whole spar). Making a laminated spar as a replacement would not only be how the factory did it, the spar would actually be HIGHER quality than a single piece. You WOULD have to be sure to get good quality laminations and glue lines, but when I do my 45 spar I will have no problem making a laminated spar.

Hank

[astjp2]

Ideal is vertical grain clear Sitka spruce in one piece but because that maybe a $3,000 board because it needs to be quarter sawed and felled on to a soft/up-slope position to keep from splitting the grain, most of the sitka spruce that remains is in protected forest along the west coast of the US and Canada thanks to O'le Slick Willie pecker head Clinton. So you will be lucky to get an equivalent grade of Doug fir, which is 15% heavier and also 15% stronger per a given dimension. Splicing is allowed in specific areas and the most cost effective if you have the special tools to scarf and get an approved glue. There are no APPROVED epoxies that meet the Mil-spec for wood in the USA per all of the dozens of hours of calling and research with the manufacturers of the epoxies. They just do not hold up in the heat or wet environment line good old resorcinol. One thing to consider is if you can get enough clamping pressure and have enough material to proof your gluing process to failure. I used a 20 ton hydraulic press to build Peterroy aileron spars. Some consider that it a minor alteration, others a major to swap the wood between doug fir and spruce. YMMV. Tim

[taylorukuk]

Thanks - Our LAA wont approve spruce in place of Douglas Fir as confirmed by them yesterday.

Anyone aware if Wag Aero replacement spars are laminated or 1 piece?