At 20:52 17 October 2018, Charlie M. UH & 002 owner/pilot wrote:
Wrong?

Answer this, did you/others run small engines for close to 2000hrs
at full
throttle with no rebuilds?
Frankly, not likely.

While most IC aircraft engines are archaic, they spend most time
at close
to full power for close to 2000 hours.

Herb, while I know you (and you know me, but maybe not
remember me), I have
to say most automotive engines trying to do what a "lump of an
archaic
engine" is normally used in US GA gas piston engines,

Rough guess........would you run a car engine at full power for
2000hrs?
Quick numbers, 45MPH for 2000 hours, say about 90,000 miles.
Me, no Frikkin way.
You, I have no clue, go for it, not my wallet.

Herb, go rush against other issues, I think you lose on this
one.......OK?


You can't compare aero engines with car engines,They are nearer to
boat engines in their usage .And tugs are worse.
To red line ,full throttle, a car you would need to tow a heavy load
up a very long hill for 2000hrs.
A sensible engineer would want to size the engine to run at max for
20 or 30seconds then throttle back to 50%.

Modern Motors are much more robust, but the way we are using
Rotax engines in modern tugs is going to lead to a lot of scared
tuggies making dead stick off field landings.
With a slippy tug like the Dianamic (probably spelled that wrong)
which I saw for the first time last month, with a blown Rotax and a
variable pitch prop you might have a chance .

I spent much of last year in a Duo Discus xlt behind a eurofox tug.
I am not sure who was most scared me or the Tug pilot, but it was
my syndicate partner that decided to give the sport up.

Max power is at max revs, so the prop needs to be set so that you
can reach max revs by lift off, but if that is only 65Kts you have no
choice but to tow at max revs if the glider is heavy like mine (2 fat
men a tank of gas and a fin full of water) ,and that is at a low
British pressure altitude.
I asked the salesman for a rough price for his as yet uncertified
dianamic with a vp prop ,,,about £160,000+tax,
At that price you can put a lot of gas in Pawnees