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Mike,
It's my belief that Bill will be offering parts
mainly and only a complete FWF if requested and some time down the
track.
Bill isn't pushing the Powersport type
Mechanical FI, but I'm sure it will be available - he's more into direct
injection, he's very progressive.
It's the maths and previous Powersport testing
that disagrees with Paul's PP sizing. Placement AKA timing will be similar
except for the size of the port. Powersport's previous ports were angled to get
the opening timing. An angled port also reduces the tendency of the port to be
larger than intended, as a larger opening will slow the velocity just when
you want it at the max. The reason is the port opening is in a curvature of the
housing.
Lynn also suggests that the manifold tubes
can be bigger but reduced at the housing inner face to get that last punch into
the combustion chamber. Lynn's suggestion of an oblong port shape also
reduces the tendency for the port face to be bigger than intended, as it's short
and wide.
I'm still trying to figure how that can be done
easily. One way would be to fill the void with melted Al and when it cooled
and shrank - weld (Tig) it around the edge. This then could be machined and
ground to shape. Bugger of a job though, but for racing it all
adds-up.
George ( down under)
George,
Yeah, I like the potential of the PP as well. Which is
why I'm not in a huge hurry to do anything yet. I'd like to see a couple of
them fly and see the performance claims proven.
As for Bill's effort, I'm sure he's going to come up
with an optimum setup. But previous posts by Bill on the subject left me
with the impression that he is going down the path of complete packages, ala
the original Powersport business model. Maybe I misunderstood him. I'd be
interested/willing to purchase a complete PP engine, but want to retain
Tracy's RD-1 and EC-2 (bought and proven). It was my understanding that Bill
was pursuing mechanical FI, his own ignition, etc... Again, maybe a
misunderstanding.
Jeff Doddridge who is doing the PP housings Paul L is
advocating is in my neighborhood. I may take a look, though I gather there is
some significant disagreement about Paul's choice of port
timing/size.
Mike Wills
Sent: Sunday, April 18, 2010 2:31 PM
Subject: [FlyRotary] Re: cooling for ground runs
Mike,
I have been a PP convert from the beginning,
because of the additional power gains, however my concerns from the beginning
were fitting of the PP, inlet size and shape and tuning for ram
effect.
I agree with Lynn on the inlet shape, however
oblong is difficult to achieve for everyone, so the round being next best and
is easier to make and fit, I settled on that.
However I still had a nagging feeling that all
PP's leak over time no matter what you do to seal them. This belief
as a result of many discussions with engine rebuilders and
racers.
Now that Bill has designed the two
piece inlet ( redesign of the Powersport
unit) with O ring sealing, I am much happier and will go that way. I have
already placed my order for some.
Bill is intending to test the PP size for power
as soon as humanly possible, however it's not the highest priority, at this
point in time.
The Powersport were a lower reduction
unit designed for max power at 6,000 rpm. I can only assume ( from
discussions) their considering redesigning with a 2.8:1 ratio to take
advantage of higher RPM, which affects a whole range of things - including the
PP size ( that certainly is my suggestion anyway). My guess is a whole
lot of work must be done before they get to that stage.
All I can say is wait for the results, I believe
you will be pleasantly pleased with the additional power, my guess is about
230 hp for a 2 rotor at 7,200 rpm - maybe more at that RPM and to 7,500
rpm.
George (down under)
Dave,
I am going to do something different with the intake
at some point. I cant get the prop RPM that I should be getting in
level flight and I refuse to hack on the prop until I convince myself that
there isnt a little more HP in the engine via a better intake. Also, my
current config wont allow the fit of an air filter and I don’t want
to fly forever without one. So would like to change the config to
accommodate a filter and ram air.
I havent decided what route to take yet. Either a
better 4 port manifold or a PP engine/manifold. Waiting to see how the PP
guys make out (Mark S., how about an update). In either case I'll build
it on my spare engine and get it all done off the airplane so it is plug and
play with minimal down time. I hope to do it sometime next
winter.
Current status. Havent had a chance to fly again
since my loss of power due to fuel starvation a few weeks ago. Went through
the entire fuel system but didn’t find a smoking gun. Replaced my fuel
filters with some higher flow units, but don’t believe that was the problem.
Replaced my injectors with the original ones I had rebuilt by RC
Engineering. The new injectors flow more fuel so now the tuning is a
little out of whack.
Also at the last oil change I switched from a
straight weight mineral oil to Mobil One. Now my previously tight engine
leaks like a sieve. So trying to address numerous oil leaks. But I think I'm
getting close to resuming flight.
Oh, one more distraction. Just about into the
soaring season so I'm thrashing trying to get my glider ready for
summer.
Mike Wills
Sent: Saturday, April 17, 2010 11:05 PM
Subject: [FlyRotary] Re: cooling for ground
runs
Mike,
Repeat after me: "I will not rebuild unnecessarily, I will fly
instead." "I will not rebuild unnecessarily, I will fly instead." "I will
not rebuild unnecessarily, I will fly instead." "I will not rebuild
unnecessarily, I will fly instead."
Lets face it. You tinkered with that thing for many years.
If you were ever going to get it right you would have done it by now.
So quit trying and keep flying. :-)
On Sat, Apr 17, 2010 at 10:51 PM, Mike Wills <rv-4mike@cox.net> wrote:
Scott,
I agree with Dave, that looks great. One picture
shows your intake manifold. Looks like you used a casting for the lower
part with a transition to tubing. Where did you get the casting? Is it a
stock Mazda turbo casting that you cut the top off of? I'd like to do
something similar. Not real happy with my current manifold and would like
to rebuild it.
Mike Wills
Sent: Saturday, April 17, 2010 9:49 PM
Subject: [FlyRotary] Re: cooling for ground
runs
Thanks Scott, You are right about what I said and I will
clarify a little. I say if it wont cool on the ground, it wont cool
in the air because when I first started flying I had marginal cooling on
the ground and marginal cooling in the air. At that time I could
idle and taxi indefinitely unless the OAT was above 85 or so, when my taxi
times would be limited to about 30 minutes. cooling in the air was
similarly limited to shallow climbs and less than full power in all but
the coolest of climates. However, Chris may be talking about high
power ground runs which is a different story. A full 5 minutes at
full power on the ground is sure to push the limits of most installations,
and a temporary spray bar fed from a hose is a reasonable thought if you
feel the need to do extended ground runs at or near full power. BTW
Scott, I just took another look at your website and picture. You
sure have done very nice workmanship. I can't wait to see that thing
fly! It is guaranteed to be one of the fastest RV's
around. -- David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.nethttp://RotaryRoster.net
On Sat, Apr 17, 2010 at 8:55 PM, <shipchief@aol.com> wrote:
Chris & Terria:
I had ground running temp issues at lower power. Dave Leonard told
me that it's important to get it to self cool at low to mid power on the
ground. He said that reliance on sufficient cooling when you come up to
flying speed most likely won't work if it won't self cool on the
ground. I took his advise and redesigned my cooling system, which by the
way looks a lot like yours with major differences being cooler ducting
and cooler orientation. He's a link to my page @ EAA326 site: http://gallery.eaa326.org/main.php?g2_itemId=1727Tracy
has commented that I should have reduced the cross section of my oil
cooler duct more quickly to force the air to uniformly pass thru the oil
cooler core. I applied that thinking to my water cooler which I built
next, and it worked even better than my cardboard and tape trial
duct. What is the engine RPM and % load that you start to have cooling
problems?
Scott
-----Original Message----- From: Chris and Terria < candtmallory@embarqmail.com> To: Rotary motors
in aircraft < flyrotary@lancaironline.net> Sent: Sat, Apr 17,
2010 10:02 am Subject: [FlyRotary] cooling for ground runs
Gents,
I am doing the higher power ground runs now, and am
only able to run for about 5 minutes before reaching 195* or so.
I’m looking for ideas on how to extend the time for each ground
run. I was thinking of adding a spray bar like others have
discussed. My thought was to drill some holes in some PVC and
connect it to the garden hose. Then put it in the intake in front
of the radiator. I would have to run the hose out the front and
clamp it down so it doesn’t come close to the prop.
I’m open to all ideas though.
I’ve attached a picture that shows my radiator and
duct work.
Thanks,
Chris
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