KR> Figuring out the laminated bent spar.

[rcollin...@charter.net]

Darren, 
I think I had better chime in on this one as I am one who has done "bent" 
spars.  The main spar is pretty straight forward but you do end up with a 
curved upper surface inside the fuselage.  The rear spar can be tricky to 
figure out, I actually built mine 2 feet longer to accomadate larger flaps, 
also tapered planform starting at the root (54" chord") thats what really 
complicated the rear spar.  If I were to do it over, I would either start the 
forward sweep of the rear spar at the fuselage or build the wing constant chord 
out to the attach points.  The landing gear castings (diehl) were also a little 
tricky because my spar is taller due to increased chord and they end up sitting 
at an angle to the spar due to the dihederal starting at the fuselage.  As I 
have said before one change from the plans creates ten more problems to work 
out in the future.  Also I would reccomend getting an opinion from an engineer 
before you make changes to the basic structure.  I don't think you can bend the 
wood in the wide direction to sweep the rear spar forward, you would probably 
need some kind of scarf joint in the center, ...again talk with engineer.  Just 
my 2 cents. 
Riley Collins
KR2-SS Lycoming
Rutledge, TN

 Darren Crompton  wrote: 
> Thanks for everyone's input on my previous post "Spruce vs Douglas Fir".  I
> have decided to build with Australian hoop pine.
> 
> That decision made, I have been taking a closer look at the plans regarding
> the timber I need to order.  I will be using the laminated bent spar and as
> described in Mark Langford's site regarding its use
> http://home.hiwaay.net/~langford/kopinion.html , I like the idea of
> extending the flaps beyond the stub wing.  If I am to taper the the spars
> from root to tip in a straight line, also doing away with the duplicate wing
> root template on the end of the stub wing, do I have to bend the laminated
> rear spar forward at the root so the two meet at the tip 15" apart as per
> the plans?  If so, how do I bend the 1/4" x 2" laminations about the 2"
> width?
> 
> Cheers
> Darren Crompton
> AUSTRALIA
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
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KR> Figuring out the laminated bent spar.

[Martindale Family]

Hi Darren

It might be simplest to just move the wing attach brackets inboard to meet 
at the fuselage, ie., still have separate but short centre front and rear 
spars. The rear brackets would then just need to be bent at a different 
angle. Whether this is acceptable from an engineering stress point of view 
you would need to confirm with an expert. There is a crowd in SE Qld that 
sells the select Hoop Pine and you can get GL1 aircraft grade ply from 
Mister Ply in Sydney. You can get around the Diehl gear issue by going to 
Grove gear which mounts under the fuselage rather than off the spar outboard 
from the fuselage.

If I were building again I would do as you intend.


John Martindale
29 Jane Circuit
TOORMINA NSW 2452
AUSTRALIA

phone:  61 2 66584767 (H)
 61 2 66869075 (W)
mobile:  0403 049990
email:johnja...@optusnet.com.au
web: www.members.optusnet.com.au/johnjanet/Martindale.htm

- Original Message - 
From: "Darren Crompton" <kr.2s.dar...@gmail.com>
To: "KRnet" <kr...@mylist.net>
Sent: Sunday, March 18, 2007 10:13 PM
Subject: KR> Figuring out the laminated bent spar.


> Thanks for everyone's input on my previous post "Spruce vs Douglas Fir". 
> I
> have decided to build with Australian hoop pine.
>
> That decision made, I have been taking a closer look at the plans 
> regarding
> the timber I need to order.  I will be using the laminated bent spar and 
> as
> described in Mark Langford's site regarding its use
> http://home.hiwaay.net/~langford/kopinion.html , I like the idea of
> extending the flaps beyond the stub wing.  If I am to taper the the spars
> from root to tip in a straight line, also doing away with the duplicate 
> wing
> root template on the end of the stub wing, do I have to bend the laminated
> rear spar forward at the root so the two meet at the tip 15" apart as per
> the plans?  If so, how do I bend the 1/4" x 2" laminations about the 2"
> width?
>
> Cheers
> Darren Crompton
> AUSTRALIA
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> Post photos, introductions, and For Sale items to 
> http://www.kr2forum.com/phpBB2/index.php
> please see other KRnet info at http://www.krnet.org/info.html 

KR> Figuring out the laminated bent spar.

[Ron Smith]

Darren Crompton  wrote: Thanks for everyone's input on 
my previous post "Spruce vs Douglas Fir".  I
have decided to build with Australian hoop pine.

That decision made, I have been taking a closer look at the plans regarding
the timber I need to order.  I will be using the laminated bent spar and as
described in Mark Langford's site regarding its use
http://home.hiwaay.net/~langford/kopinion.html , I like the idea of
extending the flaps beyond the stub wing.  If I am to taper the the spars
from root to tip in a straight line, also doing away with the duplicate wing
root template on the end of the stub wing, do I have to bend the laminated
rear spar forward at the root so the two meet at the tip 15" apart as per
the plans?  If so, how do I bend the 1/4" x 2" laminations about the 2"
width?

Cheers
Darren Crompton
AUSTRALIA
The spar center sections must be the same length. My spars were bent so that 
the stubs bend up AFTER the outside fuselage wall. The rear spar must have the 
same bottom length center section. Mine was flat for 44 inches, main and rear. 
See my pics on my site.


Ron Smith
Kr2ssxl
Buckeye Arizona
mercedesm...@yahoo.com
http://ronsmith.myphotoalbum.com/albums.php

-
8:00? 8:25? 8:40?  Find a flick in no time
 with theYahoo! Search movie showtime shortcut.

KR> Figuring out the laminated bent spar.

[Darren Crompton]

Thanks for everyone's input on my previous post "Spruce vs Douglas Fir".  I
have decided to build with Australian hoop pine.

That decision made, I have been taking a closer look at the plans regarding
the timber I need to order.  I will be using the laminated bent spar and as
described in Mark Langford's site regarding its use
http://home.hiwaay.net/~langford/kopinion.html , I like the idea of
extending the flaps beyond the stub wing.  If I am to taper the the spars
from root to tip in a straight line, also doing away with the duplicate wing
root template on the end of the stub wing, do I have to bend the laminated
rear spar forward at the root so the two meet at the tip 15" apart as per
the plans?  If so, how do I bend the 1/4" x 2" laminations about the 2"
width?

Cheers
Darren Crompton
AUSTRALIA