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George,
Your right, my apologies to Bill. It did come across as
pretty gruff. If you've followed previous posts of mine regarding performance I
am very interested in knowing how my airplane stacks up compared with other RVs,
both rotary and Lyc powered. It is hard enough (and very frustrating) when
people post performance numbers at a variety of altitudes, numbers posted based
on IAS or GS without accounting for environmentals, let alone numbers based on
theoretical calculation. How do we respond to critics of rotary installs without
accurate performance numbers?
I'm sort of in the same position as Don. I believe based
on his previous numbers posted that our performance is roughly equivalent. I
know that my performance is currently less than optimum. I have too much prop
for my current HP. I am limited by my gear ratio. I believe I am giving up some
HP due to a less than ideal intake manifold. Unlike Don, I am content with
current performance (for the moment).
I'm looking forward to hearing about how some of these
P-Port engines work out. I am considering building up a new P-port, with RD-1C,
and new prop and doing a swap sometime down the road. In the past week Paul
posted a synopsis of the original Powersport install in their RV-4 and Alan
Tolle's RV-3. I'd forgotten how cool those setups were - it was meeting Alan and
Everett Hatch that sold me on the rotary in the first place. Their Superlight
engine was a work of art. My RV-4 is the best performing airplane I've ever
owned. Imagine what it could do if it had another 70HP and lost 150 pounds (the
Powersport RV-4 with Superlight weighed about 860). That should provide Harmon
Rocket performance without having to build another airplane.
Mike Wills
Sent: Thursday, March 25, 2010 10:25 PM
Subject: [FlyRotary] Re: Turbo Planning
Mike,
Your a hard man, however I do agree with both
the Mazdatrix and Powersport results and would expect their operating at optimum
configuration and 100% VE.
The question in my mind will we all achieve this in
our less than perfect installations - probably not.
I can't remember exactly but powersport was running
two PP sizes, 38mm or 40mm early version and the later 44mm. I believe Bill
Jepson is awaiting the results of a more recent 44mm dyno run. That 210hp may be the old 44mm HP numbers - can't
remember exactly. Then again it may be the smaller inlet as they were running
6,000 for take-off RPM. A smaller PP will give greater inlet speeds reflecting
in VE.
George ( down under)
Sorry, not buying it Bill. If you are going to quote
speeds here, quote speeds, not calculated speeds based on so many variables
that the end result is meaningless. That sounds like something we'd see on the
other list, not here. As far as I know, Don's best reported speed is 174 IAS
(and IAS is not all that meaningful either). Based on performance that
Don has actually reported his performance is roughly equivalent to mine
(and I'm both prop and gearing limited). His performance may have
improved since he reported those numbers. In any case I'd prefer to stick
to facts.
Speaking of the other list, Paul has video of a
PP Renesis on a dyno at Mazdatrix cranking out near 250HP @7500RPM. And
he had the dyno sheet to prove it. Powersport claimed 210HP at 2700 prop RPM
(their reduction ratio was around 2.2; roughly 6000 engine RPM). I
believe they also had dyno data to prove it. I'm anxious to hear how Mark
Stietle's PP 20B performs.
Mike Wills
Sent: Thursday, March 25, 2010 6:25 AM
Subject: [FlyRotary] Re: Turbo Planning
Mike,
Don didn’t report speed. I took his pitch and
rpm and figured it. That speed at cruise is what he would get with no
slippage or “lift” from the prop. Most of the folks with the Catto are
actually getting higher speeds than would be calculated which indicates that
the prop is producing “lift”, not slippage.
But his engine rpm with that big prop are higher than
any I have seen. With the rotary, rpm = horsepower. If you aint
making the rpm, you aint making the horsepower. It doesn’t seem to
matter what you have done to the engine…ported, PP, turbo, supercharger.
If you look at the dyno charts that are all over the web, you will see that
torque is pretty flat after about 4K, about 150 ft lbs. The horsepower
is around 150 at 6K, maybe 180 at 7K, and 200 at 7.5K. You can get more
horsepower than that, but only if you scream it up to 8K or 8.5K.
All the charts I have seen are within 10 horsepower of each other at all
rpms. The difference in total horsepower is always a higher max
rpm.
We all talk about wanting to cruise at 5800 and make
200 horsepower…it aint happening! Not with the
rotary.
Bill B
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mike Wills
Sent: Thursday, March 25, 2010 1:17
AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Turbo Planning
I went back and looked at Don's
previous post. Saw reference to climb performance, RPMs, and temps, but no
speed numbers. Has he previously reported cruise speeds over 200? Last post
from him that I saw with any speed numbers reported 174MPH IAS at
8000. If he's over 200 now, wow those are good
numbers!
Sent:
Wednesday, March 24, 2010 9:15 PM
Subject:
[FlyRotary] Re: Turbo Planning
Those are the best numbers I have seen with anyone
with a Renesis so far. In fact, I have not heard of numbers that good on
any 13B. Don is getting over 200 MPH with a cruise prop and climbing at
over 1400 fpm with it. The only way he is going to do better is either
with an electric CS prop and/or turbo. If he shaves the prop off to say,
74”, he will get a couple hundred more rpm, but will probably lose in total
thrust. Diameter is a big determiner in
thrust.
I would like more pictures of Dons intake and
exhaust!
Bill B
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Al Gietzen
Sent: Wednesday, March 24, 2010 3:05
AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Turbo Planning
1. When I read your stats in your first paragraph, the
first thought that
comes to mind is that there is too much prop.
Ditto.
Al
G
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