I agree, Mike. It all depends on whether
the set up is tuned for your regime of operation – if it is then it will probably
work well, if not then disappointment.
A PP designed for the all out LaManns
racing circuit is not necessarily the correct one for our application – in
fact, I don’t see how it could be unless perhaps you have a CS prop and
are going all-out racing.
But, Everett
did take the time and effort to develop the right parameters for aircraft
use. The climb of Alan Tolen in his Hatch powered RV-4 was an awesome sight
I am told. Ended up destroying the gear box – not certain but think
it was a Ross unit – about the only thing available at the time that
would fit under the cowl of an RV-4.
Ed
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Mike Wills
Sent: Friday, March 26, 2010 10:36
PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: P-Port
performance
I hear you. Recalling the presentation Everett Hatch
gave on the Powersport engine, the spent a lot of time to come up with a PP
engine that was tuned for lower RPM operation. That included tweaking port
timing, port/intake diameter, and length. They had something that worked pretty
well.
Sent: Friday,
March 26, 2010 4:02 PM
Subject:
[FlyRotary] Re: P-Port performance
One of the things is your P porting needs
to match your operating (real operating) regime.
Many a person has found that because we do
not have shiftable gears nor most of us constant speed props that the magic power
numbers
At 7500 and higher rpm may not be
attainable. The reason is that you can have an overported engine that
never gets past 5800 rpm. This is because at that rpm the power may not
be sufficient to overcome the prop load due to poor intake performance at the
lower rpm.
I found out almost a decade ago that
things that work in one application (like Rx-7 racing) just great - may well
suck in another application.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Tracy Crook
Sent: Friday, March 26, 2010 1:57
PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: P-Port
performance
"I'm looking
forward to hearing about how some of these P-Port engines work out."
This is the only current flying P-Port that I know of. Same engine that
Paul L. talks about that he Dyno tested at Mazdatrix. Here are a few
clips from Mark Supinski's Mustang II w/ P-port 13B first flight
tests. Hard to draw solid conclusions from first flight especially
at that altitude but the max rpm with that small prop do not look all
that good. There may be a lot more potential when things are worked
out.
Tracy
K00V - Meadow Lakes Airport, Peyton CO
OAT: 50F
Winds: 5kt out of north
Field Elevation: 6875
Density Altitude: 7680
Mazda 13B rotary, NA with Peripheral Porting
2.85:1 redrive, standard prop rotation
Takeoff
roll was 1500 feet max;
Water temps throughout the climb were a chilly 178F max.
Oil temps were not as kind, 197F on takeoff, 217F when departing the
pattern, and 241F at 10,000 feet. Oil temps quickly dropped back to
215F on level out,
Maximum rpm was around
7000 (~2450 prop). Given that our prop is only a 68x68, we would
expect to be able to get to the electronics limit of 8000
On Fri, Mar 26, 2010 at 12:58 PM, Mike Wills <rv-4mike@cox.net> wrote:
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.
Sent: Thursday,
March 25, 2010 10:25 PM
Subject:
[FlyRotary] Re: Turbo Planning
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.
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.
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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