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


 Thank you Paul. I appreciate that.
 Benjamin

The engine can run surprisingly long without any oil - I've heard a few
stories, one where the rebuilder forgot to add oil ;)
There are videos around of people intentionally blowing up engines -
IIRC, one lasted several minutes at 9k without any coolant.
Take a look at some of the charts that Paul has posted for rpm vs oil use.
4oz per gallon is a crap load of oil.  For 4oz per gallon you probably
want a (non-stock) high energy ignition system, hot plugs and/or high
6-9k rpm to avoid fouling plugs. That sounds like super oiled race car
pre-mix. IIRC, several people adding pre-mixed 1oz/gallon were seeing
2stroke oil accumulate in the pan at 5-7k use. Cheers
Cary

The 4 oz per gallon test mentioned by Jim Mederer was probably
done with one MSD cap discharge ignition unit per spark plug.
Because that is or perhaps was the ignition of choice for Jim.

We had a guy run the engine up no load stuck WOT to over 10K and
it seized. He chiseled it apart and put new bearings in it
and then flew it for several 100 hours before crashing it
in the woods at night on a un lighted dirt strip during an attempted
landing. He walked away. The guy lived a charmed life.

Paul Lamar