SR3500 Upgrades - IMPORTANT info for WING attachment!!!!!!
Posted: Fri Feb 17, 2012 9:38 pm
Here's some important information for all you SR2500 to SR3500 upgrader's
and those building the SR3500 from the start.
PRINT THIS OUT AND PUT IT IN YOUR MANUAL SOMEWHERE SO YOU DON'T FORGET!!!!
I have been working with Brian Godden over the last week to clear up some of
the APPARENT measurement discrepancies in the front and rear spar attach
fittings. I had been measuring everything up for fit (that didn't seem to
work out ) prior to assembly and to add to the confusion MAM was shipping
out 6 x W-513's when you only need TWO (2). The first thought was the wings
should have an extra one or two W-513's installed to the rear spar to make
up the stack height to match the width of the FUS-700 spacer on the
fuselage. THIS IS NOT CORRECT. Make sure you are doing the following. Brian
will be clarifying future upgrade instructions and I am sending this out to
clear up those that already have it, or have already done it!
Each wing has only one W-513 and one W-514 installed to replace the old rear
wing attach fittings you remove (as shown in the instruction pictures). This
is a total width of only 0.180". The new FUS-700 spacer that goes between
the 2 x FUS-706 rear attach fittings, is 0.3175" thick. Therefore when you
go to assemble the wings to the fuselage, unlike the zero clearance rear
attach "slip" fit that gets bolted tight on the SR2500 (Rebel and Elite),
the SR3500 will have a clearance fit of about 0.1375".
****THIS CLEARANCE IS NOT TO BE FILLED WITH SPACERS AND IS TO BE LEFT AS A
FLOATING ATTACHMENT***.
The bolt should be tightened to the point where the FUS-706's are parallel,
as spaced by the FUS-700, and not tightened any further to allow the
W-713/714 to float on the bolt. I know it seems strange but stress analysis
shows greater strength this way, than if tightened up and allows the load to
go against the forward wing attach fittings (thus the extra gussets, packers
etc up there to add)!
This puts great importance on the location that the wing gets bolted TIGHT
at the front attach. The final location must allow the rear wing attach
fittings to be somewhat centered in between the FUS-706's without putting
any pressure against either of them. Before you press those W712 steel
bushings (that aren't discussed in the upgrade instructions, but you can see
one installed in the picture showing what rivets not to drill out in the
leading edge skin) into the front spars new W-709 and W-710 attach fittings
take some measurements. Brian has apparently found that the front bushing is
a little thick and most likely will need to be milled down to allow the rear
attach not to push against the rearmost FUS-706. My suggestion is to measure
your wing from the rear outer face of the new rear attach fittings (W-514)
to the front face of W-710 without the bushing in. Compare this to the
distance from the inside wall of the rearward FUS-706 to the inside wall of
the new forward FUS-701 that was riveted to the carrythrough tube. The
difference between the fuselage measurement and the wing measurement, less
another 0.06875 (half the .1375 clearance) will be the approximate thickness
required on the flange of the forward W-712 bushing. Mill it off to this
thickness and press her in! Then your wing should fit properly and don't
forget that you will still require a spacer between the rearward W712
bushing and the rearward FUS-701 as the front fittings MUST be held tightly
in place. This spacer looks like it will be about 0.1405" PLUS what ever you
have to mill off your W712. Could be about 40 thou more depending how well
the bushings seat in the W-709/710, as they have a radius on the inner face
of about 20 thou that I allowed for in the overall width.
Hope that is clear, if not send me or Brian an e-mail for clarification!
Regards,
Wayne G. O'Shea
www.irishfield.on.ca
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and those building the SR3500 from the start.
PRINT THIS OUT AND PUT IT IN YOUR MANUAL SOMEWHERE SO YOU DON'T FORGET!!!!
I have been working with Brian Godden over the last week to clear up some of
the APPARENT measurement discrepancies in the front and rear spar attach
fittings. I had been measuring everything up for fit (that didn't seem to
work out ) prior to assembly and to add to the confusion MAM was shipping
out 6 x W-513's when you only need TWO (2). The first thought was the wings
should have an extra one or two W-513's installed to the rear spar to make
up the stack height to match the width of the FUS-700 spacer on the
fuselage. THIS IS NOT CORRECT. Make sure you are doing the following. Brian
will be clarifying future upgrade instructions and I am sending this out to
clear up those that already have it, or have already done it!
Each wing has only one W-513 and one W-514 installed to replace the old rear
wing attach fittings you remove (as shown in the instruction pictures). This
is a total width of only 0.180". The new FUS-700 spacer that goes between
the 2 x FUS-706 rear attach fittings, is 0.3175" thick. Therefore when you
go to assemble the wings to the fuselage, unlike the zero clearance rear
attach "slip" fit that gets bolted tight on the SR2500 (Rebel and Elite),
the SR3500 will have a clearance fit of about 0.1375".
****THIS CLEARANCE IS NOT TO BE FILLED WITH SPACERS AND IS TO BE LEFT AS A
FLOATING ATTACHMENT***.
The bolt should be tightened to the point where the FUS-706's are parallel,
as spaced by the FUS-700, and not tightened any further to allow the
W-713/714 to float on the bolt. I know it seems strange but stress analysis
shows greater strength this way, than if tightened up and allows the load to
go against the forward wing attach fittings (thus the extra gussets, packers
etc up there to add)!
This puts great importance on the location that the wing gets bolted TIGHT
at the front attach. The final location must allow the rear wing attach
fittings to be somewhat centered in between the FUS-706's without putting
any pressure against either of them. Before you press those W712 steel
bushings (that aren't discussed in the upgrade instructions, but you can see
one installed in the picture showing what rivets not to drill out in the
leading edge skin) into the front spars new W-709 and W-710 attach fittings
take some measurements. Brian has apparently found that the front bushing is
a little thick and most likely will need to be milled down to allow the rear
attach not to push against the rearmost FUS-706. My suggestion is to measure
your wing from the rear outer face of the new rear attach fittings (W-514)
to the front face of W-710 without the bushing in. Compare this to the
distance from the inside wall of the rearward FUS-706 to the inside wall of
the new forward FUS-701 that was riveted to the carrythrough tube. The
difference between the fuselage measurement and the wing measurement, less
another 0.06875 (half the .1375 clearance) will be the approximate thickness
required on the flange of the forward W-712 bushing. Mill it off to this
thickness and press her in! Then your wing should fit properly and don't
forget that you will still require a spacer between the rearward W712
bushing and the rearward FUS-701 as the front fittings MUST be held tightly
in place. This spacer looks like it will be about 0.1405" PLUS what ever you
have to mill off your W712. Could be about 40 thou more depending how well
the bushings seat in the W-709/710, as they have a radius on the inner face
of about 20 thou that I allowed for in the overall width.
Hope that is clear, if not send me or Brian an e-mail for clarification!
Regards,
Wayne G. O'Shea
www.irishfield.on.ca
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