Gentlemen,
Iâ??ve been following these discussions regarding the slide throttle and
wondered if anyone knows about the slide throttle that BMW made for the
M3â??s back in the late 80â??s early 90â??s in the DTM series in
Germany.
http://e30m3performance.com/tech_articles/engine-tech/dtm_slides/index.htm
I canâ??t figure out from the pics how the mechanism works. It appears
that the sliding component is a metal (aluminum or SS) plate with some
Teflon coating?
Also found another link to a discussion on slide throttle and barrel
throttles. Can someone elaborate on the barrel throttle and how it
operates.
http://www.ten-tenths.com/forum/showthread.php?t=89467
Paul C
Here are some 3D barrel throttles I have been fooling with.
Paul Lamar ...No rotor no motor.
Paul,
Here's an idea for your cylinder barrel throttle. If you made the end of
the cylinder the inlet, like a log manifold, you could do away with the
long slots in the barrel. You would only need the bores leading to the
intake tubes. I've attached a example. The part could be made simpler,
but I have shown coped inlet tubes and bell mouthed tubes. A Teflon
sleeve on each end, or 2 Teflon encapsulated o-rings could be the
bearing surface.
Bill Jepson
You have a two tube P-port configuration shown.
Best used on a four side port engine as the plenum is out near
the end. You need the slide throttle in near the rotor housing
on a p-port to minimize the storage of exhaust contaminated
intake air.
Here is a possible 3D application for the combined plenum and
barrel throttle.
If you really want to make it easy operation you could use
the ball bearing trick on each end we used in the LAEV prop
rather than Teflon. Last dwg.
Paul Lamar
True Paul this would be BETTER for multi-port. However many P-port
engines, including the one you tested with the Webber will run just fine
with the throttle upstream. I've worked on P-ports with carbs several
times and the idle really wasn't that bad. Are we all looking for
trouble on this issue? No disrespect to the group intended, but almost
ALL ICEs have some form of crossover or overlap. 2-cycles being the most
extreme example. When the rotary is in the normal operating range we
don't have anything to worry about. One of my CFI's, and the examiner
for my checkride suggested no less than 1700 RPM in the pattern. (level
flight) Prop RPM of course. That is 4800 RPM with a 2.85:1 gearbox. I
like the barrel valve/plenum idea since it consolidates two functions it
wouldn't require any more space than the slide throttle. You need a
plenum for the slide throttle anyway afterall. There are a multitude of
ways to make a workable system, but this looks like a good possibility. IMO
Cheers,
Bill Jepson
The p-port is marginal at 1700 RPM with out the slide
throttle being close to the rotor housings. We ran a Weber
carb p-port engine on the dyno and it did not like
4800 RPM part throttle all that much. WOT was another matter.
I would stick with what Everette Hatch came up with, namely
the throttle as close to the rotor housing as possible,
as at least 3 airplanes are flying with it.
BTW NSU also used that config. I think that is were Everette
got the idea in the first place.
Paul Lamar
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