On 2/1/06, Ed=20 Anderson <eanderson@carolina.rr.com&g= t;=20 wrote:=20

You are right, Jesse - no conflict = here. If both=20 a reciprocating engine ( which is normally a iron block(or = steel sleeve=20 inserts) with an aluminum piston) and a rotary loose coolant, my bet = is the=20 iron block will at some point seize from overheating. Because = the=20 aluminum piston will expand faster than the iron/steel due to the=20 heat. Just the opposite with a rotary (as at least two/three = folks=20 have proven), the aluminum housing expands (and some = compression/power is=20 lost) faster than the iron rotor - so no seizing even though the = engine is=20 cooked.

Never said you wouldn't damage a rotary with = a loss of=20 coolant, just that it would keep running as long as then engine=20 had fire and fuel. Landing with a damaged engine with = some power=20 available beats dead sticking in a seized engine in my opinion.=20

Ed

In my limited experience of overheating rotary engines and = then dead=20 sticking onto freeways, you can expect about 4 minutes from = inital=20 overheat to complete loss of engine power. The engine will not = seize,=20 but the complete loss of compression will prevent any power = production.

I invite other to verify my data :-)

--
Dave Leonard
Turbo Rotary RV-6 N4VY

I think TTDS (time till dead stick) in a loss of coolant=20 scenario depends on a lot of factors. After replacing a = broken=20 tension bolt during a Texas RV fly-in, the coolant pressure cap = failed to=20 seal up due to a mod I did to the filler neck (long=20 story).   I though the pressure looked low on takeoff but = ignored it=20 (dumb, dumb) because temperature was just fine. It stayed that = way for=20 about 12 minutes. I was pleasantly zoned out when the = overtemp=20 alarm went off. My first instinct was to throttle back to low = power (I=20 was at about 5000 feet by then) to protect the health of the = engine. GPS=20 showed that I was 6 minutes away from nearest airport and the = engine was=20 running nicely when I shut down after landing. Was at at very = low power=20 the whole time after the alarm since I was essentially=20 gliding.

After topping off with straight water and fixing my cap = problem=20 I flew back to Florida with no problems and the engine did not suffer = any=20 damage at all.   If I had not throttled way back I'm sure it = would=20 have been a very different story though.

Tracy