Dear Paul.

1)  Is it true a Wankel can still power a plane in flight up to half an
hour
even if it has lost all its coolant ?

2)  What is the effect, (both positive and negative)  on a Wankel engine
of too
much 2-stroke oil in the fuel ?

Best regards.
Benjamin

No I don't think so. Maybe for a couple of minutes.
You should find a place to land as soon as it starts to overheat.
You should also install a cooling system pressure gage as that
can be an early warning sign. It is also useful for a preflight check
by manually pumping up the cooling system with air to 30 psi
(assuming you have a 30 psi pressure cap which you should) and
watching for a slow reduction in pressure indicating a leak.

It is very very important that you use the finest plumbing available
as the cooling system is critical. No automotive stuff. Don't nickel and
dime the cooling system. I recommend 1.5 inch OD aluminum tubing where
ever
possible and silicone rubber  hose widely used in tractor trailer trucks
for
connections. Make sure the tubes have beads on them. Tubing beaders can be
bought from several sources. Also use 50 50 premix coolant and
change it out every two years for new.

There are special hose clamps called constant tension.
These have springs in them that allow
them to expand and contract as the aluminum tubing expands and
contracts with heat. They are made by Breeze and sold in truck
stops. WW II P51's generally used two clamps per connection. That
is two on each end of the hose.

In addition for the finest connections possible buy
some of Jeff's Wiggins couplings. These are widely used on
airliners and Formula 1 race cars. The racers pay over $100
each but Jeff makes them and sells for a real low cost
$40 per set.

Scroll down to the bottom of the first page on
http://www.rotaryeng.net

I have written a book on Wankel cooling sold by AC Spruce.
Every now and then we have a direct special.

Up to 4 ounces per gallon of 2 cycle oil are OK. More than that
and you could foul the plugs. Less than an ounce per gallon and
you risk wearing out the apex seals and or overheating the apex
seal springs causing them to fail.

Paul Lamar


Benjamin

I can tell you from experience that it will run for at least 15 minutes at
reduced power.  I had the water pump impeller seal let go and dump
all the coolant that was above the level of the water pump overboard.
I had a water pressure gauge but it never really changed much from about
15 psi when I noticed my water temp climbing over 210 degrees.  I
immediately
turned back to the airport and reduced power to 4000 rpm.  Gps gave me
10 minute ETE at this power setting to the airport.  The oil temp slowly
climbed
to about 250 by the time I reduced power (Mobil 1) for a straight in
approach.
The engine never missed a beat the whole time.

When I shut it down and pulled the cowling off everything was coated in
coolant.
At that time I could not tell where it was leaking from.  I let it cool off
and came
back the next day and filled it with water and watched as it ran out the
water pump
weep hole and both exhaust pipes.

I tore down the engine and replaced the  water pump and all rotor housing
seals and redesigned
my cooling system.  I have started and run it without a load and it seems to
run fine.

I am currently extending the nose on my long ez so I can move the battery
forward
to compensate for the heavier rotary engine than the O-235 it was originally
designed for.
So I have not done any hi power ground runs with it yet.

I think the aluminum rotor housing expands more than the cast iron rotor and
keeps
the engine from seizing like a piston engine.

Mike Perry
Long Ez, 13B
N981MP