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Rob,
The main reason the Renesis is much quieter and easier on mufflers IMHO
appears to be because of the side exhaust ports on the sides of the
rotors split the exhaust into smaller packages. The exhaust manifold
is much lighter than the RX-7 manifold because it uses tubing for the
exhaust pipes with retaining some cast iron for the manifold flange.
Flew 170 miles yesterday and returned today - The Renesis ran great and
coming home today with 2 on board with luggage I was doing 170 MPH TAS
@ 7500' EM-2 showed about 20 mpg @ 22 inches manifold. This was not
full throttle! I'm now up to 140 hrs on the RV-7A with the Renesis
engine - stock from a wrecked car - RX-8 ignition coils, spark
plugs, exhaust manifold, part of the stock intake and Renesis fuel
injectors.
Rob wrote:
Thanks Bill for your advise. I guess
I will make my own, although it seems the Reneses manifold is quit well
constructed to reduce noise as well as stand up to the heat in
conjunction with a muffler, based on what I have read on this list so
far.. What I'm most concerned about is the noise. I currently fly a
BD-4 with a Ford V-6 and I'm constantly trying to get the noise to some
reasonable level. Would adapting the Reneses be worth the trouble, in
your opinion? Or how about adapting two 13-B manifolds? Any thoughts on
this would be appreciated.
Robert
Robert Bollinger
MR 722, 1000 N,4th ST
Fairfield IA 52557
(641)919-3213
rob@mum.edu
-----
Original Message -----
Sent:
Thursday, February 05, 2009 11:00 AM
Subject:
[FlyRotary] Re: 20B manifold
Robert,
The manifold could probably be lightened for non-turbo applications.
The problem is that if you remove material in the wrong place the cast
iron is likely to crack. Even if you want a non-tuned log manifold you
are going to be way ahead by making it from SS tubing and plate. The
only reason for the cast manifolds at all is the ability to make them
cheaply in production.
Bill Jepson
-----Original Message-----
From: Rob <rob@mum.edu>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, 5 Feb 2009 8:16 am
Subject: [FlyRotary] Re: 20B manifold
Bill,
Do you think the 20B manifold
could be lightened or would it be a waste of time to even attempt it.
Robert Bollinger
MR722 MUM
Fairfield IA 52557
(641)472-7000 ex2068
(641)919-3213 cell
rob@mum.edu
-----
Original Message -----
Sent:
Wednesday, February 04, 2009 12:46 PM
Subject:
[FlyRotary] Re: 20B manifold
Rob,
I have a 20B and the manifold without the turbos is a very heavy chunk
of cast iron. I don't think it would be in danger of melting, but is
just too heavy. I do NOT believe the Renesis Exhaust manifold would be
made to fit practically. The Renesis has side ports with a rectangular
profile. The 20B is a 13B with an extra rotor and one of the spacings
is longer due to the intermediate housing. The best method is going to
be a built up manifold, aand several are available over the counter.
Usually expensive, but much less hassle. Racing Beat made one for using
a single turbo for racing in the past. I don't know if it is still
available.
Bill Jepson
-----Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, 4 Feb 2009 9:34 am
Subject: [FlyRotary] Re: 20B manifold
Rob,
The Renesis manifold has an inner shell, an outer shell, and
a heat shield on top of that. I'm not positive, but the inner
shell could possibly be made of inconel. The outer shell appears to be
stainless (probably 321).
Since the Renesis has three exhaust ports, I have often
wondered if it could be modified to work on a 3-rotor. Keep in mind
that the port spacing on the Renesis is the same while the 20B
unequally spaced. That's due to the one larger side housing that
contains the 3rd main bearing. So, if the ports are big enough, and
the bolt pattern matches, you would still have to add an extension
between two of the ports to make it line up. If that is all it
requires to make it fit, it could be worth a try.
Mark S.
On Wed, Feb 4, 2009 at 11:12 AM, Rob <rob@mum.edu>
wrote:
I would be interested to know
the weight. I didn't realize that a cast exhaust manifold made for a
20B could actually melt. It sounds like the Renesis manifold would be
better.. Is the Renesis manifold stainless steel or what?
Robert Bollinger
MR722 MUM
Fairfield IA 52557
(641)472-7000 ex2068
(641)919-3213 cell
rob@mum.edu
-----
Original Message -----
Sent:
Wednesday, February 04, 2009 8:10 AM
Subject:
[FlyRotary] Re: 20B manifold
Robert,
I have one that came with my 20B. I don't want to sound
negative, but I don't think it is realistic to use on an a/c. First,
it is incredibly heavy because it is designed to incorporate the twin
turbos. And it is made of cast iron, so it would probably melt at
prolonged WOT operation. And the passages are very restrictive to
exhaust flow. I could weigh mine and send some pictures if you wish.
Sorry, but I don't want to get rid of it because I have plans for a
3-rotor auto installation where it would be useable. Maybe you could
modify a Renesis manifold to fit. It would require some welding, but
it is probably more likely to work than the original 20B manifold.
The cheapest manifold would be to use 304SS handrail
material. I built my first manifold using that material and after 100
hours it looks like it would last for a very long time. Ed Anderson
has been using this material on his a/c for a long time. My exhause
flange material was 1/2" mild carbon steel and it was holding up fine
as it doen'st see the high heat that the pipes do. The problem was
with the mufflers. They take a real beating. Try to space the muffler
as far away from the engine as possible.
Mark S.
On Wed, Feb 4, 2009 at 7:43 AM, Rob <rob@mum.edu>
wrote:
Al and Greg,
Thanks for your replys on
this subject. I realize the manifold would be too heavy but I was
hoping I could widdle it down some how. Greg, I would be interested in
your suggestion for doing that. I'm putting this 20B in a BD-4.
Robert
Robert Bollinger
MR722 MUM
Fairfield IA 52557
(641)472-7000 ex2068
(641)919-3213 cell
rob@mum.edu
-----
Original Message -----
Sent:
Tuesday, February 03, 2009 11:10 PM
Subject:
[FlyRotary] Re: 20B manifold
Al, you don't want the stock
exhaust. Get one built. If you want to know one way it's done, let me
know.
Greg Ward
Lancair 20B in progress
-----
Original Message -----
Sent:
Tuesday, February 03, 2009 8:25 PM
Subject:
[FlyRotary] Re: 20B manifold
Does
anyone on this list have a 20B exhaust manifold that came with their
engine that I could buy?
No; but I
do know the thing is massively heavy. I looked at one when I got my
engine, and decided quickly it was not very interesting for an
aircraft. Maybe if radically modified . . . Just my opinion.
Al G
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