The Murphy Builders Site

Hey guys !!!

I just noticed a slight buckling of my firewall just next to the top left engine mount base !!!

I have an 0-235 with a light weight starter, prop, alternator etc.....is there a requirement to fit
a "spreader bar" across the top of the mount between the two top mounting points ?

(I'm going to make & fit one anyway....can't see any other way of arresting this problem)

I seem to remember Alistair Yeoman in N.Z. talking about beefing up his firewall and fitting a spreader bar across the top mounts some time back....but I figured that as he had an 0-320
and was flying in and out of "rough strips" that this wasn't necessary for all....Yes ? / No ?

Anyone else out there had this same problem....or have I F&%$@D something up here ?

Thanks

Rick & Wendy Harper
541R

Rick there's a picture here http://wrayt.tripod.com/construction.html of Mam's fix for this and Waynes. Just click on the picture for a larger view
Rick Harper wrote:

Hey guys !!! I just noticed a slight buckling of my firewall just next to the top left engine mount base !!! I have an 0-235 with a light weight starter, prop, alternator etc.....is there a requirement to fita "spreader bar" across the top of the mount between the two top mounting points ? (I'm going to make & fit one anyway....can't see any other way of arresting this problem) I seem to remember Alistair Yeoman in N.Z. talking about beefing up his firewall and fitting a spreader bar across the top mounts some time back....but I figured that as he had an 0-320and was flying in and out of "rough strips" that this wasn't necessary for all....Yes ? / No ? Anyone else out there had this same problem....or have I F&%$@D something up here ? Thanks Rick & Wendy Harper541R

--
Wray Thompson ...Rebel 306 ...home page http://wrayt.tripod.com/
My ICQ number is 29764664

Rick, I have been telling guys for 5 + years that the firewall needs to be reinforced for ANY engine installation, other than the 912. There is no real weight difference between an O-235 with the old starter and alternator and an O-320 with light weight accessories (maybe 10 to 15 pounds tops). You can either do my firewall plate fix (purchase or make your own from .063" sheet) or the MAM "float fix" channel. You will probably find it pretty hard now, that she is done, to do the MAM fix as it usually runs right through where the wires, throttle, mixture, tach cable etc go through the firewall. My plates can be done without removing the engine, by undoing one mount to firewall bolt at a time (or hoisting the engine and doing a couple at a time). If you have a conical mount, you can get away with just the top plates and just spacing the lower two mounts out the same .063" with a AN970-5 penny washer under the mount flange on each side, as the mount already has a cross tube.

If you need any pictuers besides the one that Wray has posted on his site, or the ones in the product section on my site, just let me know!

Good luck and Best Regards,
Wayne G. O'Shea
www.irishfield.on.ca

----- Original Message -----
From: Rick Harper (rjwh@ozemail.com.au)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Monday, May 28, 2001 9:12 AM
Subject: HELP !


Hey guys !!!

I just noticed a slight buckling of my firewall just next to the top left engine mount base !!!

I have an 0-235 with a light weight starter, prop, alternator etc.....is there a requirement to fit
a "spreader bar" across the top of the mount between the two top mounting points ?

(I'm going to make & fit one anyway....can't see any other way of arresting this problem)

I seem to remember Alistair Yeoman in N.Z. talking about beefing up his firewall and fitting a spreader bar across the top mounts some time back....but I figured that as he had an 0-320
and was flying in and out of "rough strips" that this wasn't necessary for all....Yes ? / No ?

Anyone else out there had this same problem....or have I F&%$@D something up here ?

Thanks

Rick & Wendy Harper
541R

Hi Rick !

Sorry, I guess we all thought that EVERYONE was doing the
"Floatfix" mods, which includes the channel on the firewall. It
seems that everyone who only has the stainless firewall will definitely
need this. (Early Rebels had a heavy aluminum firewall with a sheet
of stainless over it - these haven't had the problem.)

There is an alternative - or an addition - available from
Wayne O'Shea. You might want to have a look at the pictures on his
web site - he puts plates in the top corners, and across the bottom.
This ties the sides and the witches hats together, strengthening the
whole firewall. (www.irishfield.on.ca)

Good thing you spotted it early - hope it won't be TOO big
a fixup .....

.....bobp

----------------------------------orig.------------------------------------
At 11:12 PM 5/28/01 +1000, you wrote:

Hey guys !!!

I just noticed a slight buckling of my firewall just next to the top left

engine mount base !!!

I have an 0-235 with a light weight starter, prop, alternator etc.....is

there a requirement to fit

a "spreader bar" across the top of the mount between the two top mounting

points ?

(I'm going to make & fit one anyway....can't see any other way of arresting

this problem)

I seem to remember Alistair Yeoman in N.Z. talking about beefing up his

firewall and fitting a spreader bar across the top mounts some time
back....but I figured that as he had an 0-320

and was flying in and out of "rough strips" that this wasn't necessary for

all....Yes ? / No ?

Anyone else out there had this same problem....or have I F&%$@D something

up here ?

Thanks

Rick & Wendy Harper
541R
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<DIV><FONT size=2><EM>Hey guys !!!</EM></FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=2><EM>I just noticed a slight buckling of my firewall just

next

to the top left engine mount base !!!</EM></FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=2><EM>I have an 0-235 with a light weight starter, prop,
alternator etc.....is there a requirement to fit</EM></FONT></DIV>
<DIV><FONT size=2><EM>a "spreader bar" across the top of the mount between the
two top mounting points ?</EM></FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=2><EM>(I'm going to make & fit one anyway....can't see any
other way of arresting this problem)</EM></FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=2><EM>I seem to remember Alistair Yeoman in N.Z. talking about
beefing up his firewall and fitting a spreader bar across the top mounts some
time back....but I figured that as he had an 0-320</EM></FONT></DIV>
<DIV><FONT size=2><EM>and was flying in and out of "rough strips" that this
wasn't necessary for all....Yes ? / No ?</EM></FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=2><EM>Anyone else out there had this same problem....or have I
F&%$@D something up here ?</EM></FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=2><EM>Thanks</EM></FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=2><EM>Rick & Wendy Harper </EM></FONT></DIV>
<DIV><FONT size=2><EM>541R</EM></FONT></DIV></BODY></HTML>

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Hi Rick,
I found buckling in that area within a few hours, I was operating off a standard grass airfield.

I had to use a portapower spreader to push the firewall back into shape, I did remove the motor and mount and placed 32thou doublers over the top mount area of the firewall ( smaller than Wayne's mod though, but it was required because the area was weakened through being buckled) and a C channel between the top two mounts as well.

I would have to say I am more in favour of placing the channel right the way across between the two mounts, it appears to me to isolate the loads completely. Though Wayne's mod seems to do the trick.

Its a real pain isn't it Rick, you have just finished building and you have to go back revisit the whole thing, But it is worth it!! I have done over 300hrs on mine now and it appears I am on top of the cliches (touch wood!) and I am probably more impressed with the versatility of the Rebel now than 200 hrs ago.

Chin up.

Cheers

Alister

----- Original Message -----
From: Rick Harper (rjwh@ozemail.com.au)
To: murphy-rebel@dcsol.com (murphy-rebel@dcsol.com)
Sent: Tuesday, May 29, 2001 1:12 AM
Subject: HELP !


Hey guys !!!

I just noticed a slight buckling of my firewall just next to the top left engine mount base !!!

I have an 0-235 with a light weight starter, prop, alternator etc.....is there a requirement to fit
a "spreader bar" across the top of the mount between the two top mounting points ?

(I'm going to make & fit one anyway....can't see any other way of arresting this problem)

I seem to remember Alistair Yeoman in N.Z. talking about beefing up his firewall and fitting a spreader bar across the top mounts some time back....but I figured that as he had an 0-320
and was flying in and out of "rough strips" that this wasn't necessary for all....Yes ? / No ?

Anyone else out there had this same problem....or have I F&%$@D something up here ?

Thanks

Rick & Wendy Harper
541R

Hey Rick,
I'm a little surprised at you having this problem already. Did you by chance drop it in from a significant heighth? What suspension are you using? Spring gear? Coil Springs? Bungees?
After 150 hrs and an 0-320, and my share of those drop tests, I had no sign of that.
I just installed Waynes firewall plates, and I managed to do them without having to pull the engine. I did have to pull about 6 rivets a side from the inside, but I'll live with that until I do pull the engine. My reason for installation is that I'm going o
n floats, but I would recomend that everyone do either the MAM fix or Waynes, no matter what. For the bullet proof fix, Wayne has done one with both! I just don't have the room behind my avionics now, so I'll just do the one. IMHO Curt N97MR



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