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----- Original Message -----
Sent: Monday, January 17, 2005 6:32
PM
Subject: [FlyRotary] Re: For Jerry: Inlet
runners etc was Re: [FlyRotary] Re: For Al EWPs & Sump Heat Exchangers
On Monday, January 17, 2005, at 06:15 PM, Leon
wrote:
Hi Jerry,
Looks
like you have copped the same treatment that I copped, and still
continue to cop. HIM (His Imperious Majesty) never misses an
opportunity to put someone down if they are right and he is wrong.
He's been bad-mouthing me for the past three
years.
Unfortunately,
the majority on the ACRE mailing list believe whatever HIM says
is true, including all the the libel and slander. And there is
no right of reply or redress of
grievances.
As
John Slade rightly says, those of us who know what it's all
about might start taking notice of him when he actually gets a
plane in the air, or even an engine running. But, what
about all the poor people who are being willingly misled??? In
the meantime I suppose, it's a case of "Them's wot can
... DO, them's wot carn't ... prognosticate!"
As
for the size of any PP runner, the ONLY way ANYONE will know is to DO
it, build the engine, and dyno the sucker. From my
perspective of a car racer, it's not only size, but actual port
timing and shape that makes a difference. This is all RPM
dependent. The higher the RPM, the more overlap and the
bigger the ports and runners that can be accomodated.
As
a racer (as opposed to an aviator), we are always trying to get
MAXIMUM power, which means BIG runners, and LOTS of ARE PEE
EMMS. Current PP thoughts are 52mm ports being fed by 60 mm
throttle bodies with a tapered runner. Great for 10,000 -11,000
RPM, But this just wouldn't work in an aircraft. The engine
wouldn't even get on the pipe until around 5,500. A two piece,
centre bearing crank is
mandatory.
Obviously,
the corollary is true. While not being a fan of PPs for aircraft
use, I can only agree with you. At the RPM we are
using in aircraft, the overlap needs to be reduced (port size,
shape, and placement on the trochoid), and the runner sizes and
lengths need to be commensurate with the gas speed required, as well
as any back pressure caused by mufflers. In the end, this can
only be a matter of applying a bit of intelligent theory and doing
some educated surmising, guided by whatever people have done in the
past, and then followed by trial and error and dyno time.
For
instance. I'm developing a four runner manifold for the race
car. The current one in the pix is steel (for ease of
fabrication), and will be replaced by an all alloy manifold once the
development is finished. So far, we have picked up an extra 25
BHP throughout the RPM range, and something like 35-40 BHP at the top
end.
I
eventually want to have computer controlled adjustable length
runners. Easily done with a stepper motor and a worm shaft.
Now I already have a ROUGH idea about lengths, based on past
expereince, but until I actually put the car on the dyno, I
really didn't know EXACTLY what length would work at
what RPM with the current style of bridgeporting I'm using, and the
actual mufflers and exhaust system on the
vehicle.
So,
I've made the trumpets manually adjustable (crude by effective), and
have done some dyno tuning and track time to see what lengths work at
what RPM. I am now at that point in time where I can get my machinist
to make an adjustable trumpet mechanism of the correct stroke. I know
HIM has been talking about it, but I'm actually doing something
practical about it!! Just do likewise Jerry. Don't let the nay
sayers get you down. In the end, you will know who's
right, because the dyno is the final
arbiter.
Cheers,
Leon
Nice
looking Bells, Leon. Point the injectors into the bell mouth and you have what
I am working on. We should have a prototype plenum with fuel rails, filters,
maybe even Ram within a month or so. I am not now nor have I ever been worried
about our p port performance. We have Everett Hatch and Alan Tolle before us
and Power Sport flying now, so we know roughly what performance to expect.
Plus I have the excellent engineering of Rolf P. predicting what our
performance will be. I have never been tempted by larger p ports, as they are
clearly not appropriate for lower rpm engines( below 8000 rpm.) Our ports will
function to that level quite nicely. They are sized and positioned to
eliminate overlap as much as possible. They open late and close late. I am
willing to predict that we will make at least 210 hp at 6000 rpm and maybe as
much as 220. At 7500 rpm the hp will be around 250. But this is just talk,
enjoyable blather actually. The dyno will tell all. If the engine can turn my
3 bladed Catto that was too much prop for a 200 hp Lycoming, I will be happy.
Jerry
Hey, Jerry....I truly hope you are very
successful with these P ports and that you get the hp numbers you are hoping
for. We will all benefit from your experimenting and fabrication
efforts. Experimenters are welcomed and encouraged on this site, not
castigated and/or belittled. Keep up the good work, and I wish
you success with your effots. Paul
Conner
<BTSRX3AirBox1.jpg><BTSRX3Trumpets3.jpg>
Homepage: http://www.flyrotary.com/
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