BTW this mount uses the Tracy trick of the oil foam separator sandwich plate
extended and thickened into a motor mount. We got to give credit where
credit is
due. A bit heavy as it is about 144 square inches by 1/4 inch thick
at a volume of 36 cubic inches and 3.6 pounds not counting a few
little holes. It is necessary and would be about one pound in any event.
Could be welded in as part of the custom pan of course.
BTW Mike Wills mount would work well and would be simpler than this one
IMHO if another hard point was constructed at the very top of the
firewall to brace the rear motor mount vertically. This one on the
other hand gives a bit more clearance around the water pump plumbing.
The extreme forward PSRU/motor-mount plate type mount would also work
with this scheme. That would give a bit more room for the front
of the pan.
Let me know if anyone wants this ACAD 12 drawing file.
Paul Lamar
Yes, please, I would like a copy of the ACAD file for the RV-4 Mount. I'm
hoping to get my conversion done by next June and the motor mount is one of
two major efforts I need to undertake this winter.
I have acquired a 13B that was originally built for racing by Pineapple
Racing here in Portland, OR ( http://www.pineappleracing.com/ ). The guy I
got it from had made a few dozen runs with it locally and this year decided
to change his RX-7 over to a small block chevy. He had me clean out his
garage of all his rotary engine stuff. Good deal. (Anyone in the market
for an RX-7 5 speed, racing clutch & flywheel, and/or RacingBeat four
barrel manifold with Holley 550 DP?) According to Ron Golden the owner of
Pineapple Racing, the engine isn't even broke in yet. I'm anxious to get
it on a stand and light it off.
The motor has some high end street port work done to it along with improved
oiling for high rpm operation. For this reason I am planning on using the
2.85 gearing (thus the second major undertaking for the winter). I also
have a few spare wood props that I can use if the prop flange is turning
that way
:-).
I'm hoping Tracy has the time to develop this drive this winter so I don't
have to. (Wink, nudge, hint, hint.)
I've ordered the EC-2 from Tracy and it should be ready to ship shortly.
It's going to be a busy winter.
Mike
Mike McGee, RV-4 N996RV, O320-E2G, Aurora, OR
OK Mike here it is. I am working on figuring out the loads so I will
know the tubing sizes and wall thickness. The loads are much different
in this mount between a six G pull-up and a six G landing due to the way
VanG braces the landing gear leg sockets to the motor mount.
Surprisingly, at first glance, the tension loads in the upper tubing
in the truss are drastically increased when you drop the airplane in with
six G's. Also the tubes running from the top of the landing gear leg socket out
to the rubber bushing gizmos are highly loaded in compression and must
probably be made out of 3/4 inch OD tubing. To be on the safe side
I would make the whole thing out of 3/4 OD .049 wall 4130.
Paul Lamar
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