Fixing a broken motor mount in a foamy

Started by Frank v B, June 21, 2021, 09:27:39 PM

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Frank v B

When a plane lands 90 degrees off a perfect flare everything goes to undesirable places.

This Pilatus did face plant into the ground.  The motor mount is loose.

Photo 1 shows the motor is not in the right place.
Photo 2 shows there are no access holes anywhere

Find a NEW #$11 X-ACTO blade and lets get going.

This post will follow the repair either from start to finish or start to garbage bin.

Stay tuned.

Frank
"Never trade luck for skill"

Frank v B

#1
Let's cut some foam.

Three things to do with a repair:
i) Always cut (tri)angles so the pieces slip back into place without gaps. 
ii) glue the wood back together so the pieces are straight and true.
iii) once the glue has dried, reinforce everything with wood, glue, fibreglass and/or carbon.

PHOTO 1- looking into the nose with the motor still attached.  The firewall was actually twisted 90 degrees in this photo.  I unscrewed the motor mount so I could glue the wood pieces back together.
PHOTO 2- saw blade at a double angle
PHOTO 3- the first lue joints are drying.  Next steps is securing it.

Frank



"Never trade luck for skill"

msatin

You used the saw to cut the triangle.
Was there a reason other than too much foam to cut with the x-acto?

Thanks
You never fail until you stop trying

Frank v B

#3
Mark,

re: "Was there a reason other than too much foam to cut with the x-acto?"

Three reasons:
- the foam was deeper than the x-acto could cut.
- the saw makes the cut nice and straight, especially because of the double angle.
- I couldn't find the saw when I started.  After the first cut with the X-acto, the saw jumped up and said "use me you idiot".  It was hiding. ;)

Frank
"Never trade luck for skill"

Frank v B

#4
The liteply firewall split in half.  I glued it in place. 

Step 2 is to strengthen it.
Cut a slot in the foam behind the firewall and slipped in the new piece of plywood (photo 57).
Drew the vent holes on the plywood with a pencil (photos 59,60) so I could remove it and cut the vent holes (62).
Added 5 minute epoxy down the slot in the foam and on the plywood, slipped it into the slot and clamped it (photo 63)

Let dry overnight.

F.
"Never trade luck for skill"

Andy Hoffer

Hey @Frank v B ,

Where's the part about repeating the landing 90 degrees off a perfect flare?!  ;D

Andy