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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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