REFLECTOR: Higher RPMS

[Rene Dugas]

Thanks to all.  I have raced boats, motorcycles and cars for years but
always appreciate others experiences and view points.  I've blown up
engines in small applications at 16,000 rpms and had lawn mowers hopped
up and blow at 3000 rpms.  I wish to be conservative but by nature I am
a racer.  I will continue to research.  I do not intend to use the
higher setting except if desired for climb out and acceleration to
cruise at 23/23 or 24/24.  Cooling has never been a problem.  I have
NACA's about one inch larger than the factor is now recommending.  Oil
in cruise is 165 degrees and CHT at 380 with EGT's 1450.  Large piston
diameter makes for large mass effect that multiplies rapidly as RPM's
increase. 
Thanks,
Rene'

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Chuck Harbert
Sent: Monday, November 20, 2006 11:15 AM
To: reflector at tvbf.org
Subject: REFLECTOR: Higher RPMS

> Question:  The AeroComposite has a rpm limit of 3000 and an overspeed
> limit of about 4000.  I was thinking of increasing my engine rpms up
> from the 2700 of the MT to 2800 or even 3000.  That is still very low
> rpms and should get better climb out on take off.  Thoughts?
>
> Rene'

-------------------

Rene, you can physically can run at higher rpms right now, and I know
that 
people who race, do just that (heard up to 3,300 rpms), but I believe
that 
most install the higher rpm engine components. I have a HIO-360 Lycoming

(helicopter) that is rated at 2,900 rpm in my V which I found out has 
different connecting rods and lighter and stronger valve train to handle
the 
higher rpms.

I've talked to Lycoming (570-323-6181) and Bart at Aerosport
(250-376-2955) 
regarding higher rpm operations. The engine makes more horsepower as
rpms 
increase (to a point) so you will be burning more fuel and have higher 
temps, particularly CHT's which may be a problem. Engine life is
directly 
affected by operating at higher temps, especially >425F, even if you are

allowed up to 475-500F (for short duration).

The higher you fly directly affects the loading on the engine because of

less air pressure (unless turbcharged) creating lower hp and less of a
load. 
Thus, you can run at higher rpms at higher altitude and still be under 
normally rated hp, but cooling is usually the limiting factor.

Your new Aerocomposite prop sounds like a winner. I've seen their blades
and 
they are beautiful. Is it hydraulic or electrically controlled?  If you 
don't mind telling us, how much did it set you back? Thanks.

Chuck H









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