Alex Eban wrote:
> Probably not more than about 3 years, but most of the new ones won't last
> more than that any way. Somebody once told me that the department that takes
> care of limiting the lifespan of the cars at Japanese factories has more
> budget than the Quality Control department.
>
Some of them are being used in home built airplanes of surprising
performance with prop speed reduction unit consisting of either a
gearing arrangement some what different than used in turboprops, and
some actually use a belt system similar to helicopters. Lifetimes of a
thousand hours have been obtained. Typical operation might be 100% for
up to 5 minutes and the rest of the time at 60 to 75% RPM.
This is a far cry from Detroit's best as of 50 to 60 years ago when we
figured 35,000 miles was about time to get rid of it and 60,000 was
almost unheard of. Those cars were heavy and solid! Of course Detroit's
engines improved too. However if you look at the standard piston powered
aircraft of today they are still using what is basically 70 year old
technology. Large displacement, low RPM engines. 6 cylinder opposed, 540
- 550 cubic inch 300 hp@ 2700 RPM with about 95% of their life spent at
75% HP or 2400 RPM @ 24 or 25" of manifold pressure. These engines have
close tolerances, but very lose fit. IOW we'd consider that piston
clearance in a car engine to mean it was almost worn out. I typically
run the 260 HP, 471 cu inch 6 cylinder at 2400 @ 24 or 25" of MP and get
about 190 mph cruise for hours with 4 people in a 50 year old plane that
grosses out at 3100#. OTOH I don't exactly get 21 MPG either. 100
octane LL also makes premium auto gas look cheap. OTOH I can get nearly
2000 miles with the tip tanks full and slowing down to 120 mph. Man,
but that'd be a long time to set there<:-))
But back to amps, why would some with big amps run them class A? The
amps already have better IM and linearity than many, if not most
exciters on the market today
73
Roger (K8RI)
> Alex 4Z5KS
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Sam Carpenter
> Sent: Monday, March 29, 2010 4:29 PM
> To: amps@contesting.com
> Subject: [Amps] Over 1.5k = Idiot?
>
> I wonder if the folks that think that way also purchase cars that max out at
> 70 MPH downhill. If so, I wonder what the lifespan of the engine is when
> driven with the accelerator to the floor all the time.
>
>
>
> Sam N9FUT
>
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>
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