REFLECTOR: Engine Selection

[Al Gietzen]

Subject: Re: REFLECTOR: Engine Selection

 

To each his own.  You can always go faster with a bigger engine, but to me
the weight and fuel consumption penalty for anything over 200 hp in a plane
this size isn't worth it.  That's just me.  A lot of guys like to build the
biggest, baddest airplane they can.  I love it.  More power to them
(literally.)  It takes all kinds of people to make up a world.  I'm one of
those "less is more", "think smarter not harder" kind of guys.  I'm shooting
for 180 mph and 25 mpg at 9,000 feet with my top door, short wing, fixed
main gear, retractable nose gear Velocity.

 

Doug;

I certainly don't disagree with that.  I knew I was making some statements
without qualifying them which can be bad thing in these forums, but
sometimes we just don't have the time.

I like to go fast.  I found cross country trips in a Skyhawk to get slow and
boring.  My early looks at the aerodynamics of the Velocity suggested that
it could do fine with some more HP, so why not use it.  I also recall Mark
Machado commenting (complaining) about the performance of the factory 173 FG
with 200 HP.  Maybe he just liked to go fast too.

 

I like to think I'm thinking harder and smarter; or is that too much
thinking?

 

I'm disappointed to hear that propellers are not more efficient at lower
RPMs. I was hoping that extra efficiency would give my diesel a little free
speed boost.

 

There are lots of variables in prop design, my conclusion was that; given
the diameter limitation we have, running up to 2800-2900 RPM a properly
designed prop can get similar efficiencies to one running at 2200.  Back in
the old days I was convinced that I wanted a Dyna-cam engine that would run
at 2000-2200, and believed there was significant prop performance; and there
may have been if we could swing a larger diameter.  

 

I'm very enthusiastic about the Deltahawk.  I think they are on the right
track, and that it is tragic that they couldn't get some of the funding that
Continental wasted on a diesel engine that they never really intended to
bring to market.  An inverted 200 hp DeltaHawk should be ideal for a
Velocity SE.

 

Al

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