The Murphy Builders Site

G'day Wayne !

I've just completed your version of the firewall reinforcement......but I used .080" 6061-T6
(I got some plate cheap through a friend....and the 80 thou' was cheaper than 63 thou' !?!)

I've just had a rush of s#!t to the brain.......
I've only installed the two top plates.......not the bottom one as well.

Will the .080" spacing on the upper mounts affect the thrust line to the point where I should be fitting
something on the lower mounts to re-instate the correct angle for the engine....or do you think
this is a "non event" ?

(I haven;t put the cowls and nosebowl back on as yet....I'm also wondering how much the 80 thou'
is going to affect the clearance gap between the spinner and the nosebowl too)

Thanks for your advice ...it looks much better now...no buckling !

(The real pisser was the wiring looms and engine stuff through the firewall....nothing that three
full days work didn't fix !)....Couldn't go flying anyway....still waiting on the new oil cooler !

Rick & Wendy Harper
541R

Yes Rick, you need to shim up the bottom two mounts by the same amount as your plates thickness. The nice thing when using .063 is, that it is the same thickness of an AN970-5 washer. Make a couple shims from your .080 plate scraps, otherwise this seemingly insignificant amount will have your propellor/spinner sitting approximately 1/2" lower at the nose bowl!

Once the bottom mounts are shimmed to match, the plates shouldn't effect your cowling fit much other than you will now have an extra .080" clearance between your spinner and nose bowl. And of course .080 less between the back of the nose bowl and your flywheel!

Happy flying,
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: Tuesday, June 05, 2001 6:50 PM
Subject: To Wayne...Re Reinforcing plates


G'day Wayne !

I've just completed your version of the firewall reinforcement......but I used .080" 6061-T6
(I got some plate cheap through a friend....and the 80 thou' was cheaper than 63 thou' !?!)

I've just had a rush of s#!t to the brain.......
I've only installed the two top plates.......not the bottom one as well.

Will the .080" spacing on the upper mounts affect the thrust line to the point where I should be fitting
something on the lower mounts to re-instate the correct angle for the engine....or do you think
this is a "non event" ?

(I haven;t put the cowls and nosebowl back on as yet....I'm also wondering how much the 80 thou'
is going to affect the clearance gap between the spinner and the nosebowl too)

Thanks for your advice ...it looks much better now...no buckling !

(The real pisser was the wiring looms and engine stuff through the firewall....nothing that three
full days work didn't fix !)....Couldn't go flying anyway....still waiting on the new oil cooler !

Rick & Wendy Harper
541R