Alex Madsen wrote:
Last week I finished my concept drawing for a tuned carbon fiber intake manifold which I may eventual start producing. After three designs I finally got
something I liked. There are several things I sill need to change (clearances, remove flat surfaces, move plenum entrance to side, and further reduce height
above engine ect). The engine block is a sketch I roughly scaled from a drawing with calipers. If anyone has a solid model of the 13B they could send to me
it would appreciate it. The runners are flattened 2 in. tube with a hydraulic diameter of 1.8 in and a length of 30 in. . I think the 30 in. is a bit long but
I need to start somewhere. The height of the manifold above the top of the engine is about 3.5 in. The plenum has a volume of 1.12 L.
I am in the middle of finals at the moment so I have not had time to refine the drawing.
Comment Questions
Alex Madsen
Jr. Mechanical Engineer
Rose-Hulman
Nice 3D work Alex. I did something similar awhile back. Kind of tough
to get the primary tuned length short enough to use the dynamic
chamber principle at 7500 RPM. Never know for sure unless we tried
one on a dyno. The last 3D is one I did.
The stock Mazda dynamic chamber is tuned for 6000 RPM for the long legs
and 3000 RPM in the dynamic chamber mode. You can see the torque hump
at 3000 RPM in the NA HP charts. Something we really don't need in
an aircraft engine.
Ed Anderson and I went around and around on this. He is currently
flying a version that is cockpit adjustable. However without a dyno
it is hard to prove it is working or not working.
A lot of systems also add a tuned length pipe from the dynamic chamber
to the air cleaner. The RX8 uses this principle with multiple dynamic
chambers to fatten the torque curve throughout the RPM range.
BTW IMHO there is no replacement for displacement when it comes to low RPM
torque. That is why I am pushing Mazda management for a 3 rotor in the RX8 :)
Paul Lamar
Alex, IMHO here is what it is going to take to get the dynamic chamber working
in our RPM ranges. Namely 6000 to 7500. Lots of R&D work for very little potential
gain.
IMHO we are much better off going with the Leman P-port configuration.
120 HP per rotor is guaranteed at 6000 RPM and 155 HP per rotor at 7500
RPM with a 2.85:1 gear box. That is 240 HP at 6000 RPM and 310 HP at 7500 RPM.
You won't come close to those numbers with side intake ports and dynamic
chambers. As I said before the hot tip ultimately will be P-port intakes
with side exhaust ports.
Paul Lamar
I agree!!!....We have to stop F'ing around......Jerry, too bad you decided to move while in the middle of the PP project :) otherwise you would have licked all of this already....So forget about R&R and get your ASS in gear and stay there...If need be kick your wife out-a-bed and sleep with the engine instead :) My money is on you to iron a lot of this shit out, c'ause you're a Doer!!!
With that said...Are you planning on attending OSH ???
Regards,
Butch
Alex Madsen wrote:
Hi
The height of my CF manifold seemed to be the major concern with my last
design. I have greatly reduced the overall height to about 2 inches.
This makes the manifold look a little unconventional. The results of my
flow calculations indicate that the increase in flow resistance will not
be very large.
Area= 2.4 in^2 (1.75 in. D pipe equivalent)
Hydraulic diameter= 1.5 in (equivalent flow resistance of pipe for
velocity from area)
Length=26 in
Alex Madsen
Alex, You are NOT getting the message. Let me be blunt for a change.
You are wasting your time with the dynamic chamber effect. What you show will
NOT WORK as a DYNAMIC CHAMBER in our RPM range. In fact it will not generate
as much peak power as a simple tuned side port manifold let alone a peripheral
port manifold. Peak power is the name of the game in aircraft engines.
We don't need a lot of torque (HP) at low RPM's like car engines do.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2003 All world wide rights reserved.
