"Michael D. Lilja" wrote:
I have been told by a couple of people as well as reading, one of the reasons the P-51 was so
fast
and efficient (relatively) was that the thrust developed by the cooling system ducting was used
to
offset the cooling system drag. What if you used the energy of the exhaust to run a turbine
wheel
in the manner of a jet engine and used the power generated to run a fan (in the manner of a
turbo
fan engine.) That would maybe not only create a higher density atmosphere for combustion (bleed
air form of turbo charging.) Blow the rest of this air over all the radiators (oil and coolant)
and collect their heat energy. Then in a concentric tube with the exhaust, duct it out the back
directly as thrust and skip the mechanical connection to the engine all together? Might be
simpler and easier. One of the draw backs I can think of would be fitting it in some where. Just
remember, if you think it has some merit, you heard it here first! :-) Thanks for the wonderful
discussions and forum. I am also glad to see someone else as interested in turbo compounding as
me.
Converting the exhaust into thrust independently of the gearing linkages sounds like a good
idea to me. However any fans that I have found with sufficient airflow for radiator cooling are
quite bulky, especially for my LongEZ. How would it work to use a transvector air amplifier
instead. They are small (1" - 5" diameter) and can convert high pressure air to high volume air
with no moving parts. An airflow amplification of 1 to 25 is common. Put it behind, not in front
of the radiator. It is easier to suck than blow through radiators. It should also give plenty of
airflow during taxiing, a common problem with pushers. I like the idea of automatically having
increased cooling when using increased power. Pelmar Engineering
http://www.pelmareng.com/Air_Amplifiers.html has a 5" unit (model # 905) that consumes 117 scfm at
80 psi and produces 2400 cfm output. This would probably not be a direct match to the exhaust
output of the rotary, but it seems like there should be some way to convert the exhaust flow or
design an amplifier to match it. Keep in mind that I am not an engineer and this whole idea may be
a waste of time. Paul or one of the other experts on this list would probably have a better grasp
of its feasibility, and recognize some issues that I haven't thought of. Some sources I have found
for these amplifiers and information about them:
http://www.pelmareng.com/Air_Amplifiers.html
http://www.arizonavortex.com/ http://www.artxltd.com/index.htm
http://www.exair.com/airamplifier/adj_air_amplifier_page.htm
http://www.vortexair.biz/index.html
http://www.tech-sales.com/Exair_Air_Amplifiers.htm
Dick Gregory LongEZ N613NC
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