Dave Leonard told me he was going to Reno this
past week with his turbo RV6 for the 2011 PYLON RACING SEMINAR.
http://n4vy.rotaryroster.net/
How did it go Dave?
Paul Lamar
Hey Paul,
I had a great time! Qualified as a pilot for the races in
Sept. Plane
did really well, except I was leaking some combustion gasses
slowly into
the coolant and had to cool and burp the system between every
flight.
I mostly didn't push the plane too hard. Fastest lap that I
timed was
217 mph. That was 40 inches MAP and about 6700 RPM. Another
lap was
212 mph at 38 in MAP and 6500 RPM. I figure that I will push
it up as
high as 45 inches in Sept.
In comparison, a 180 hp RV-8 (faster airframe) with a c/s prop was
running about 192 mph around the course at WOT and 2600 rpm.
The F1
Rockets and Super-6/Super-8 were running between 230 and 245
mph (O-540 CI
[250 to 300 HP] or similar engines with usually shorter wings).
Awesome experience.
Bob Mills did a better write up:
http://www.vansairforce.com/__community/showthread.php?t=__73286
<http://www.vansairforce.com/community/showthread.php?t=73286>
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net <http://n4vy.rotaryroster.net/>
http://RotaryRoster.net <http://rotaryroster.net/>
Wonderful news Dave. Not bad for an RV as the relatively low
aspect RV
wings
creat more drag in a high G turn. It is over 5000 feet up there so
I am sure your turbo helped a lot.
If it is leaking coolant you may have a broken tension bolt.
Perry Mick
and I found that out the hard way out in Palm Springs.
If you don't find a broken bolt you can always go up a size to
1/2 inch
from 10 MM. Mazdatricks has a new jig for doing it.
Dave Garber was running 45 inches on his 12A's in the huff and
puff.
We almost got the 4 ready to run. The fuel drains were missing
(new ones
ordered) and I have one battery with another on the way. The
wings are on
(of
course) and the tail is mostly on. I have a new girl mechanic.
5 feet
tall,
36-18-36, with small hands to help get the tail on :)
Paul
Quote
"I have a new girl mechanic. 5 feet tall,
36-18-36, with small hands to help get the tail on :)"
End of quote.
And you post pictures of Perry ? Shame on you Paul :)
Dave this is great news. This is how to make people sit up and
take notice
of rotary installations in aircraft. The history of air racing
bears this
out.
Is there any way we could collectively help you out Dave ? There
are enough
people here with a vested interest, perhaps there is something
that will net
a couple of extra knots that might otherwise be a stretch for you.
John
Well, I'm not sure that the uninformed will be very impressed. They
will only notice that I am in last place. A few knots are not going
to help much. During race week I will probably go to 45" for at
least the qualifying run, and post a qualifying time above 220,
maybe as much as 230mph. But either way, I will probably be dead
last and a few more knots are not going to matter much one way or
another.
But the informed observer might take note. I was much closer to the
speed of the super-6 than to the RV-8.
I have been kicking around the idea of installing an ADI system. Or
maybe a water spray bar for the inter cooler. I was seeing 55 deg C
during the race, which is not too bad but I would feel better if I
got it down some. Does anyone have experience with ADI?
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net <http://n4vy.rotaryroster.net/>
http://RotaryRoster.net <http://rotaryroster.net/>
PS. I am not leaking coolant, except for burping it out past the
overflow IF I have not recently burped the system. The compression
gases seem to slowly accumulate in the system until the coolant finally
gets pushed out. But the cooling system pressure checks to 40psi
without any leaks.
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
Something is deflecting then allowing the compression gases to
get into the water jacket. Torque check all the tension
bolts.
The two rotor is 160 cubic inches. One cannot hope to defeat piston engines FOUR
TIMES THAT SIZE easily!!!! 640 cubic inches. Finishing the race and showing the
colors is a start. You are doing amazing well Dave and I don't think you will
finish last.
The top speed is proportional to the cube root of HP.
The cube root of 40 is 3.4. The cube root of 45 is 3.55. 355/3.40 is 1.05.
1.05 times 217 MPH is 227.85 so you should go about 227 or 228 MPH with 45
inches of Hg.
Drag reduction is far more fruitful than increasing power.
Are you using all the racing tricks like go fast tape on all the seams?
The gap in the elevator horns should be sealed with soft foam that still
allows the elevator to move. Same goes for the flaps and ailerons.
Any air leakage from bottom to top or top to bottom in the case of the
horizontal tail due to inevitable air pressure differences allows air to
flow through the gaps and increase the drag.
High G turns aggravates this situation because the lift coefficient
must increase. Tapered longer span wing tips also help in high
G turns. It was why the Spitfire could out turn an ME109. England
practically won the war on that feature alone :)
VAF quote:
"The triangular wing-tips Jim Smith has mounted to his RV-6 have not only
increased his speed above 8000' dalt, but also down to at least 4000' dalt. He's
getting 2 mph more at 4000' dalt, 3 mph more at 8000' dalt, 5 mph at 10,000',
and 7 mph at 11,000'."
High altitude is a similar situation to a high G turn in that induced drag
due to lift becomes greater due to a required increase in the lift coefficient.
(C sub L) It is why air liners have high aspect ratio wings with tip sails.
The formula is C sub L Squared! divided by pi times the aspect ratio.
http://en.wikipedia.org/wiki/Lift-induced_drag
What about the tail wheel? Are you running a tail wheel
fairing? Some RV guys use a smaller tail wheel with fairing for
racing only.
Steve Beckham, do you have Tracy Saylor's phone number or email address?
Tracy has some low drag landing gear strut fairings he used to sell.
Tracy has gone 237 MPH in the Sun 100 with his RV6.
If the water and oil temperatures are cooling OK duct tape the openings
closed a bit to cut cooling drag.
The CG should be adjusted until the elevator is neutral. Another way of doing
more or less the same thing is adjust the thrust line up or down. It is
adjustable in the Questair Venture and a lot of my motor mount designs.
The 4 has shims for the horizontal angle of attack.
55 C intake air temperature is getting up there. A water spray on the inter
cooler would help as would ADI but I can offer no guidance on the amount.
Paul Lamar
--
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