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I can give you all some information on the aero injector/carb or whatever.
My intention was using it on the single rotor, and I am still using it on my
test stand engine. Once it runs, it seems to be doing pretty good. The downsides
are, when the engine stops fuel keeps running into the engine unless you shut
the mixture control to the lean stop. Vice versa, starting can be very tricky
operating the mixture operating the starter. Another issue is fuel pressure.
Whenever the fuel pressure changes the mixture changes too. It is not easy to
maintain the low fuel pressure if you do not have gravity feed. It is hard to
finding a fuel pressure regulator that can hold something like 2psi.
I am still using it on the test stand because it does not lean out on high
power settings as regular carburetors do.
In the airplane I switched to the ROTEC TB40, which is essentially a
Ellison carburetor with an actively controlled pressure regulator. After I
finally figured out how to get the reference pressure right, it looks like the
best thing short of an EFI. I have not encountered any problems with engine
starting, hot or cold.
I am not flying yet, but high speed taxi tests, including lift off, look
very good.
Richard
Sohn
N2071U
http://www.fairpoint.net/~res12/home.html
Sent: Saturday, November 24, 2012 4:57 PM
Subject: [FlyRotary] Re: Defined Autoworks parts site / Mark's 20B
Date: Fri, 23 Nov 2012 21:59:55 -0600
Joe,
Yes, those are nice, but a bit pricey considering a 3-rotor would need 3 @
$395/ea. You would need to be able to sync them which might be a bit risky
considering the big fan nearby. Of course this isn't necessary if only
using one.
Mark
On Sat, Nov 24, 2012 at 3:03 PM, <jskmberki@windstream.net> wrote:
Mark,
The carb was aero carb or aero injector here is the link
http://www.aeroconversions.com/products/aerocarb/index.html
Joe Berki
Limo EZ
13b P Port
On Saturday, November 24, 2012 2:25 PM, Mark Steitle <msteitle@gmail.com>
wrote:
> Joe,
>
If you decide to go ahead and use the slide throttle, I would consider
welding the front and back covers to the spacer, leaving one end removable for
assembly. This would greatly reduce the leak factor.
>
If I were to build another slide throttle, I would really try to
incorporate roller bearings for the slide to run on rather than a friction
interface. Then integrate primary injector bungs downstream of the
slide. I would also add an air bleed in order to facilitate balancing
the rotors at idle. Then figure out some way to safety the throttle
cable to the slide.
>
On a side note, I think the only time the slide throttle is superior is
during WOT operations. Anything less and the slide creates a lot of
turbulence in the intake runners. That's a non-scientific personal
observation of mine, FWIW.
>
Mark
> >
On Sat, Nov 24, 2012 at 1:28 PM, <mailto:jskmberki%40windstream.net> wrote: >
Mark,
Thanks for the reply. I have the 3/8" teflon slide throttle built
by Mazda Custom Parts Inc. by Doc Custer. I have my injectors
near the bellmouths inside of a plenum but I think I will have puddling so
it looks like a redesign is in order. I emailed the company that makes
V carb or Vinjector used in the Sonnex VW engine and asked if anyone
inquired about using 2 of those for a P Port. No one has used one on a
rotary that they know of. I have to rebuild the engine and that is
going to cost a lot so redesigning the fuel system might be better to
accomplish now. I have got zero room to accomodate any of the needs
for the P Port. I think you have the closest to optimum working P Port
in aircraft use. I was thinking of a gasket between the spacer and the
side plates which would more provide room for the teflon. I also saw
that Tracy is building a EC-4 for test stands and airboats. What if you used
2 of them one for each rotor? Appreciate any input.
Joe Berki
Limo EZ
13b P Port
> >
It was the original design of PL, expanded for the 3-rotor. It
used a solid 3/8" teflon slider. When I initially built it I didn't
allow for expansion of the teflon slider and so the hotter things got the
tighter the slider was in the cavity. He now recommends thin sheets of
teflon bonded to an aluminum slider. I didn't try that, so I don't
know if it corrected the problem. I modified my slide throttle by
opening the tolerances up until it would work when hot.
> >
But then it also leaked. Like I said earlier, the fuel would
puddle before the slide. If there wasn't a perfect seal between the
plates and spacer, you'll get leaks onto the exhaust. Not a good
situation. This could have been part of the problem I was experiencing
with rough idle.
> >
Also, the slide throttle does not allow for balancing the individual
rotors. So, precision is the word when drilling. My pieces were
built using a Bridgeport, but then I had to weld the short tubes to the
outer plates. I may have gotten things a little "off" when cleaning up
the welds. But I could feel one rotor cutting out during ground
ops. I tried fine-tuning it with a small fine file, but was never
happy with the results.
> >
And it didn't allow for a truly positive method of retaining the
throttle cable. The design as shown did not provide for a lock nut or
setscrew to keep the throttle cable from backing out. Mine never did,
but the thought was always in the back of my mind. It was also very
difficult to screw the throttle shaft into and out of the assembly for
installation and removal of the slide throttle. I feel that part of
the design could use a bit more engineering to address this issue.
> >
Those are some of the issues that I've identified. I'm sure that
most could be overcome, but I ran across these sweet little one-barrel
throttle bodies for approx. $100 on ebay. So, I bought them and ended
up using them. They have ball bearings for the throttle shaft, which
makes them smooth as silk. They have a bung located downstream of the
butterflies for the primary injectors. So, no more fuel
puddling. The only real problem with them was that the intake
incorporated a bell-mouth. But I was able to work around that.
If it wasn't a p-port engine I could have gone with one larger TB before the
intake plenum, but p-port engines run better with the butterflies near the
ports. These fit the bill nicely. And it idles much better
now.
> >
Mark
> >
P.S. Part of the idling problem was that I didn't have diodes
installed on the fuel injectors. Best I can tell, this is a problem
for the 3-rotor engines running the EC-2 controllers. Once I added
those the idle improved a lot.
> > > >
On Sat, Nov 24, 2012 at 10:23 AM, <mailto:jskmberki%2540windstream.net>
wrote: > >
Mark,
Do you have any info on the throttle bodies like brand and
source? Can you expand on problems with the slide throttle?
How thick was the slide? Thanks for any help
Joe Berki
Limo EZ
13b P Port
> > On Saturday, November 24, 2012 7:36 AM, Mark Steitle
<mailto:msteitle%2540gmail.com> wrote:
> >
> Doug,
> > >
That's true. It is almost like an entirely different engine,
especially the MAP readings. I guess you could compare it to
installing a radical cam in your family driver. It would drastically
alter the driving characteristics. Tracy is working on a fix for the
MAP issue on P-Port engines. It only hits two addresses between idle
and 4500 rpm. Hopefully, the fix will help it to run smoother
through the transition.
> > >
It also required a whole new intake. I tried the slide
throttle, but there were some issues I didn't especially like, so I built
one using three 46mm snowmobile throttle bodies. It has worked out
great. It especially improved the idle characteristics, probably due
to having the primary injectors located downstream of the throttle
plates. I had some fuel pooling issues with having them located
upstream. The snowmobile tb's also operate much smoother than the
slide throttle. At idle, vacuum sucks the slide against the
downstream side plate with a significant force, making it difficult to
work the throttle.
> > >
> > > And... it now
burns more fuel than before. DUH! I could throttle back and
fly slower, but who wants to do that???
> > >
Mark S.
> > >
On Sat, Nov 24, 2012 at 3:43 AM, <mailto:DLOMHEIM%252540aol.com> wrote: >
> >
Mark Steitle wrote:
>"...What I can say is that I picked up 20+ knots on the top end
over the original side-port 20b motor".
That is outstanding Mark! I'd almost bet that your PP
modification was one of the "easiest" ways to gain those hp numbers vs.
a turbo / supercharger add on? Probably wouldn't seem like it as
you were going through the "tweaking" phase, etc... :)
Doug
> > >
> > > >
> >
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