Vince Orton wrote:

... SNIP ...
- Could the compressor section of a large turbocharger be used

to pull air from the backside of a radiator, and then dump it
overboard (or air blast hot spots)?  Is this "out there"?  I
think this has merit since increasing power causes an increase
in cooling airflow.  Heck, I suppose the turbocharger could
still maintain an induction compressor section, too.

Just some ideas ...

Thanks,
-Vince Orton

Turbo compression can heat the air all it wants ... it's going
overboard, remember?

In fact, why not blow it over the exhaust pipes on the way out?  Maybe
in an "exhaust pipe duct/box" to keep the rest of the cowl cool.

The "turbo fan" would *suck* from the back side of the radiator,
probably in a ducted arrangement.  It too would work better on high
power takeoffs and climbs.

Is there merit to this, or am I chasing shadows?

--
Thanks,
-Vince

-Matt Prather wrote:

Newbie here,

Exhaust backpressure is almost never a good thing on 4 stroke engines,
though there is energy to be extracted from the hot exhaust gas flow.
Putting a turbo on the exhaust will allow you to recover some of this energy,
and make thrust out of it.  However, its worth it to consider what tradeoffs
will be required by implementing this solution.

The best solutions to engine installation problems make the largest amount
of thrust horsepower from a given amount of fuel,  weight, complexity, over
a reasonable range of operational parameters (ambient temperature, altitude,
airspeed) and at a reasonable price of components.

Properly implemented, what you are suggesting likely would contribute to
the goal of efficiently making thrust but what are the tradeoffs in terms
of cost,
installation weight and complexity?  Since there aren't installed systems
that
use exhaust flow to drive a waste heat cooling fan, you would be committing
to the engineering process required to design and debug a system.  Not
impossible, but you have to decide where you want to spend your time.
Engineering is all about tradeoffs.

Beyond that, you would have to consider whether the energy you extract
with the exhaust turbo was contributing to thrust as much as other solutions
would.  This likely hinges on the efficiency of the implementation as much
as anything else.  If you got exactly the right turbo, and routed the
plumbing
correctly, things would go pretty well.  Again, you are back to engineering
effort.  Iterations would be expensive because you would be using custom
hardware instead of off the shelf items.

My gut feeling is that you would be better off doing the conventional thing.
Use a turbo as the first stage of muffler.  Run the compressed air through
an intercooler, then into the intake manifold.  Scale and install the cooling
system components as described by the list of parameters that Paul laid
out.  Use an inteligently designed cowl flap (maybe with an aneroid control
system).  Go flying in your machine that is overall a better product than
anything
that's been mass produced.

In my opinion, you have proposed an interesting idea, but its not an 'order
it up, bolt it on' thing.  If you can do the work to prove it out (or find
someone
else that will), go for it.

Them's my 2 cents.

Thanks and regards,

Matt-

VE N34RD, C150 N714BK
- 

Well said Matt.

Paul Lamar
 
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