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Interesting indeed!
I took the 360 CID displacement of a 180 HP Lycoming and
calculated the airflow (assuming 100% VE which is doubtful) at 2700 rpm and I
get 281 CFM. That's just a hair more than a 13B at 6000 rpm which gives
277 CFM which gives a 160HP (standard day at sea level) .
Since the stock aircraft engine does not have anymore
compression than the rotary and since we can wind our engines much higher than
6000 rpm, I would say this supports Lynn's comment about:
1. aircraft engines not producing ( in normal
operation) the power we all supposed they did.
2. That the rotary can (does not mean all do)
produce more HP than the stock Lycoming 320-360.
Another point is Tracy Crook's max performance 13B (old and
new) will out run any stock 360 with breath to spare.
I understand Rusty has a 360 for sale, cheap
{:>)
Ed
----- Original Message -----
Sent: Wednesday, February 08, 2006 9:55
AM
Subject: [FlyRotary] Re: 6 port?
Hi Lynn,
You're right that I would truly be surprised IF this
were true. I don't buy it though. Got any evidence to
support this statement?
Cheers,
Rusty (180+ HP Lyclone on the
way)
There is ample evidence. After a thousand or so hours in the dyno room,
you can develop a feel for such things. Look at the ID of the carb or TB
on the 180. How many CFM? Enough to support the advertised HP? At what rpm is
that HP rating? Can't get a dyno sheet for your new engine? And if you could,
what is the date on that sheet? Is it for your engine, or for an engine built
years ago?
Typical of the breed is a HP rating at 3,200 to 3,400 RPM (from years
ago) and with a prop on them they won't turn up 2,700 on the ground. And only
get to the rated power RPM in a dive. Hardly usable power. If you
get behind one of the Black Max type rebuilds it feels like a rocket,
because it is at or very close to its (Factory) advertised HP. And they do
that with porting to match the flow rates of the cast heads. And you cannot
put your finger in the ring end gaps.
If you can find a list of torque outputs for a list of aircraft engines,
compare them to the rotary driving through a 2.85:1 reduction box. Now you see
that the rotary does very well against the airplane engine. Look at it
backwards and compare the swept volume of the two engines at any prop RPM.
Since the rotary does outrun most of the 160 HP powered planes, would you
assume that those rotaries have way more than 160 HP? Or, perhaps the
160s had a bit less. I can get 3+ HP per cubic inch, would that make a
great Lycoming or what?
Take off in a Cessna 150. Alone, so it won't be over gross. Did that feel
like 150HP?
Did it feel more like 79HP? Why yes it did.
Lynn E. Hanover
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