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Thanks Bill and Dennis. I think you have answered
all my questions. I think I will build a manifold from
scratch.
Robert Bollinger MR722 MUM Fairfield IA 52557 (641)472-7000
ex2068 (641)919-3213 cell rob@mum.edu
----- Original Message -----
Sent: Thursday, February 05, 2009 5:21
PM
Subject: [FlyRotary] Re: 20B
manifold
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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