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?
It's true that
dyno sheets are hard to come by, but then I've never received one with a car, or
with my engine from Bruce, or from Rotax, etc.
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.
So you're saying
that you can buy New Lycoming O-360's, rated at 180HP/2700 rpm, then take
them to a dyno and show that they make "nothing close to their advertised HP"? If so,
you'll be a rich man when you sue them. I wouldn't start spending the
money though :-)
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.
One thing to
remember is the difference in how dyno results are collected. For the
Lycoming, they test an engine under best case conditions in a
test cell. The aircraft manufacturer can lower these numbers
a bit during installation with restrictive filters, exhaust
systems, etc. For the car, the test is done under worst case
conditions, so we assume the actual installed power in an aircraft to be a
bit higher. If you look at it this way, it might be fair to compare
a "160" HP car engine to a "200" HP aircraft engine.
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.
Considering that
it only has a 108 HP O-235 engine, that sounds about right for a fixed
pitch prop :-)
Don't get me
wrong, I hope to see lots of rotary engine clearly outperforming Lycoming in
reliability, and performance, but I frankly don't think that day has come.
I'm rooting for Bill Dube's 6 port
intake, though.
Cheers,
Rusty (someone
has to play the bad guy)