Rob W M Shipley wrote:

Has anyone on the list considered this as a means of normalising

performance

at altitiude.

Rob
Rob W M Shipley
rob@robsglass.com

We don't need no stinking normalizing. :-) The rotary is very
robust and tolerates lots of boost at sea level and as high
as you care to fly.

Paul Lamar

david mccandless wrote:

I like that Paul, direct to the juggular. My sentiments exactly; Dave

McC

Sorry Rob. That sounded a bit flippant. I was trying to be funny.
I just thought it ironic that the term "normalizing" was invented as
an attempt to reassure people that were worried about their air
cooled aircraft piston engine exploding when turbo charged. With good
reason too as aircraft engines are right out there at the stress limits.
They must be that way to keep the weight down and the power to weight
ratio where it is. That means if you make modifications that increase
the HP, even the slightest amount, you can rest assure the life will be
much shorter. It was not really failure prone it was "life challenged"

:-).

If it was "normalized" you never had anything to worry about because
it never generated any more power than it was designed for.

The rotary on the other hand can run at four times the power we
are asking from it. Jim Mederer at Racing Beat has over 250 hours
at 300 HP per rotor at 8500 RPM on the dyno and much much more life
to come with no signs of failure or wear so far. This advantage
of the rotary is hidden in automotive use. When they fail in automotive
use it is usually something easy to fix such as the cheap nylon tubes
that feed oil to the apex seal cracking with age. Of course any
engine will fail if they don't get lube oil. They will also fail if
you over heat it long enough.

All this is why I think we are being too conservative limiting the
RPM to 6000. I think we have nothing to worry about and we can
run it to at least 7500 RPM with a 2.85:1 gear box for takeoff
and climb.

BTW Perth guys, have you heard from Ian Beadle lately? Tried to
contact him by email and heard nothing back.

Paul Lamar

Rob W M Shipley wrote:

Hi guys,
I probably need to add at least some explanation for my enquiry regarding
normalising engine power with a supercharger.
I'm building an RV9A and Van has been quite vocal on the subject of not
putting too hot an engine in this due to the fact that the plane has proven
faster than was expected in the design phase.  This makes the use of 180HP
engines a bit probelmatic since using the output, unless reduced by
altitude, is going to push the cruise speed up substantially above Va and
probably close to Vne.
I don't at present anticipate a need for more than 160hp but I would like
this available at altitude since there are some significant "hills" here in
the West.

I had wondered about supercharged normalising as a method of achieving this
without worrying about any increased heat to dissipate from a power boost
and wthout having to deal with intercooling.
I'm sorry to have ruffled feathers but I should probably have given this
explanation first.  I certainly didn't mean to suggest that turbocharging
wasn't the best method of producing an increased output and the enquiry
wasn't meant to suggest that I had a better suggestion to offer.
I really do respect the collective expertise this site offers and will be
most appreciative of any suggestions anyone feels able to offer.
Rob
 

The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.