Paul Carey wrote:
Hi Paul
Thanks for the repy - appreciate all the assistance from a fellow aviator.
(By the way, I worked for Eagle Aircraft here is Perth years ago on the
engine side, and went to Norton in England to view there pp rotary engine,
and brought one back and did extensive testing in a test truck,
incorporating a lot of the intake work done on the Powersport 13B - long
runners with remote throttle butterflies in the rotor housings - worked a
treat).
Wow! the explosive power of a tea spoon's worth of gasoline (nitro
methane?).
How fast are/were you going before this happened?
It went bang in the burnout - very spectacular to say the least. It went
bang due to a big leanout caused by faulty injector nozzle holders)
If you want to watch the video's go to my web page and click on the links
www.aeromanagement.com.au/site/flyblown.html The video has begrudgingly
made me quite famous here in Australia!
I don't have a three rotor version of the intake manifold. You could
take two 13B versions and cut one down, weld the two parts together
and make a three rotor version.
Are your's for standard 13B intakes? The Cosmo 13BREW and 20REW intakes are
substantially bigger in size. (Drawing attached)
Yes the 13BREW are rather rare in the states.
Ours is only 90 degree. It is designed to be welded to round aluminum
tubing
bends or pipe. That is the approach I suggest for your use as it keeps
any one runner's cross sectional area at a minimum and hence the
explosive
volume of each runner limited. Bring all runners to the blower adapter
plate
and use bell mouths to gather the air. This will limit the volume of the
explosive power of the mixture everywhere but in the blower itself. There
is nothing you do about that. The drag racers have been blowing up
blowers for years :)
Archie on here may have a few tips along those lines as he builds
blown hemi fuel dragster engines. I think there may be some sort of pop
off
valve you can use to keep the blower from departing the engine.
Yes - a burst panel - see below.
The plenum approach, as shown in these pictures, of course must be
very very strong indeed to withstand a back fire. Hense it becomes very
very heavy. Even 13 mm thick wall plate might not be strong enough.
Also the flat sections of plate have tremendous bending forces
on them tending to distort the plate as you have well demonstrated here.
A round tube or pipe will withstand much higher pressures.
I am thinking of a combination of long tube runners meeting in a much
smaller plenum.
BTW our manifold may not have enough meat to extensively port a three
rotor.
You might look into having a 90 degree version (transition from oval port
to
round tube) made by a four or more axis NC mill. Many of the V8 cylinder
heads here in the states are now ported by NC machine
tools. The Extreme Rotaries guys in Seaford Victorie tell me they
have an extensive NC machine shop. Once the NC program is written and
debugged additional items are much cheaper. There could be a market
for these in the states.
Paul Lamar
Paul C, Looks pretty wild! I hope I'm not covering old ground here but
here goes. In Blown fuel cars in the US the sanctioning bodies often
require what have come to be called "sneeze valves." They are open
rectangular areas on the manifold sealed with a plate and gasket.
springs hold the plate closed to just above normal blower pressure.
In a backfire the plate is lifted off releasing the pressure safely.
This eliminates some of the need for super thick intakes. It can also
prevent one of those blower explosions that sends the huffer into a
low earth orbit! Please excuse me if I'm covering old ground. I can't
tell from the pictures if you already might be using this feature. Bill
Jepson
Paul - we had a SFI Burst Panel installed in the top of the plenum - that is
a legal requirement in our class. The thin panel bursts at 75 psi (which it
did), but the plenum was too large and too weak, so it exploded. In V8 blown
cars, blowing a burst panel is sort of a regular occurance, and normally
just requires a new burst panel screwed in and back to racing. Obviously
that is what we need too - a manifold that can withstand the explosive
force.
Please let me know if your manifolds can fit the 20B from the attached
picture - port size. Otherwise I may get some milled as you say - or cast.
Regards
PC
Paul Carey LAME, MC
Aero Management - aviation consultants.
www.aeromanagement.com.au
(08) 9371 5205 0418 959 892
Our manifold won't fit your needs Paul. Too small.
Paul Lamar
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