CHevy V8 and the Super Rebel (2500).

[Rickhm at home]

I have looked through the archives of email and agree with many of the
observations I have read. I see the following challenges before me as I
approach this problem. My state of progress is I have completed both
wings, tail and 60% of the fuselage. As I plan forward, I see the next big
challenge will be engine.

My current plan is to put in an LS1 engine. The LS1 is an iteration on the
old tried and true small block V8, but with upgrades to improve the
performance of the engine. It is an aluminum block and has worked well in
other aircraft. In a SR it offers lots of power. I should point out that
I live in Colorado and as I look west from my home I see the passes at
11-12k and tops at 14k. The extra horsepower is there for altitude, not
sea level takeoff or faster cruse. At 15k, the air pressure is down about
45% from sea level. The simple math indicates the same is true of HP.
This is often countered with a supercharger. Unlike many auto
applications, the boost in an aircraft is intended to maintain sea level
intake pressure at all altitudes with a regulating waste gate. This is a
little different than most auto applications. I am unsure if I will put in
a supercharger, but am considering it. I have re-enforced from the door
posts forward to ensure structural integrity under potentially higher load.
This was done by adding an .040 (2024-T3) doubler over the standard right
and left skin forward of the door post. This doubler also covers the
entire door post.

PCM(Powertrain Control Module): The standard PCM from GM may work fine for
my application. Because it is an aircraft, other LS1 installations have
created a redundancy. In these applications there are 2 PCM's and a
supporting harness. From the cockpit, the pilot selects which PCM is in
control just like a mag. Should one of these fail, you have a backup.
This adds complexity to the design of the ignition system, but seems
reasonable. I would hazard to guess everyone has had the computer in their
car go out somewhere along the way in life!

Oxygen Sensors: Because 100LL is leaded, this creates a little bit of a
challenge. I have been told of 2 approaches. An O2 simulator (cost ~$100)
and entry of a special VIN number that allows you to bypass the O2 sensors
and utilize a mass airflow portion of the PCM. Apparently this is used in
Saudi where they still run Tetraethyl lead gas.

Cooling: Typically in other auto-engine installations, the radiator is
significantly reduced because of the increased airspeed or the space
restrictions. Likely this is more space oriented than airspeed related.
Any success stories with the SR and V8 installations? Additionally, there
is often an oil cooler that is feed by a NACA scoop. Presently, challenges
remain are complete understanding the heat transfer process. What is known
is how to install aerodynamic radiator and calculate the air flow. What
isn't known is the required heat dissipation or how to approach this in an
SR. Similarly, the pressure vs flow rate through the radiator isn't known
until I pick a radiator. It is likely that the rate limiting item is the
radiator, but this remains to be addressed. Any thoughts?

Fuel Supply: Most typical aircraft engines are gravity or low pressure
feeds. The LS1 requires something around 52-60 psi of fuel pressure. The
location of the fuel pumps is also a question. The likely location will be
:
1) Between the wing tank and the fuselage with a high pressure line running
to the engine
or
2) Below the floor with low pressure feeds from the wings to a 1 L header
tank and high pressure feeds to a Y with check valves (see below) and to
the engine from the Y.
Another complication is 2 fuel tanks. If a pump fails, the Y connection
needs check valves so that the flow doesn't end up in the other wing.

I have looked at 2 or 3 PSRU units. Any thoughts on quality, reliability,
etc. ?

I know there are other V8 builders out there. Any thoughts on cooling,
fuel supply, etc.

Rick Muller
70SR




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[Reed, Britt/FSC Salt Lake]

Mark - I am really interested in this topic and have been following the LS1
for years - I am now thinking that the LS6 (408 HP Peak - 350@4800 RPM) is
the natural evolution and has some definate advantages - I recently called
West Coast Corvettes and talked to them about the LS6 to see if I could get
a $7500 "crate" motor from them because several sites listing LS6 on the web
have no availability - The guy at West Coast Corvettes said that he has done
a bunch of the LS1 engines for aircraft applications - he also has access to
the LS6 - They start talking about using billet machined parts (xtra $7500
con rods etc) but I think that the stock motor is more than adequate. He
also mentioned that next year GM is going to have a 500 HP Corvette option.
I asked about turbocharging and he referred me to the Ligenfelter who
developed the turbo system for the LS1/LS6 - It is out of control expensive
but he expects the price will come down as they recoup their engineering
costs.

I also like the Northwest Aero Products PSRU and web page -
Also check out http://yarchive.net/air/index.html

I have the option of the M14P but have a couple of years to decide -

Britt Reed 194SR





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