On 2/1/06, Ed
Anderson <eanderson@carolina.rr.com>
wrote:
You are right, Jesse - no conflict here. If both
a reciprocating engine ( which is normally a iron block(or steel sleeve
inserts) with an aluminum piston) and a rotary loose coolant, my bet is the
iron block will at some point seize from overheating. Because the
aluminum piston will expand faster than the iron/steel due to the
heat. Just the opposite with a rotary (as at least two/three folks
have proven), the aluminum housing expands (and some compression/power is
lost) faster than the iron rotor - so no seizing even though the engine is
cooked.
Never said you wouldn't damage a rotary with a loss of
coolant, just that it would keep running as long as then engine
had fire and fuel. Landing with a damaged engine with some power
available beats dead sticking in a seized engine in my opinion.
Ed
In my limited experience of overheating rotary engines and then dead
sticking onto freeways, you can expect about 4 minutes from inital
overheat to complete loss of engine power. The engine will not seize,
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
scenario depends on a lot of factors. After replacing a broken
tension bolt during a Texas RV fly-in, the coolant pressure cap failed to
seal up due to a mod I did to the filler neck (long
story). I though the pressure looked low on takeoff but ignored it
(dumb, dumb) because temperature was just fine. It stayed that way for
about 12 minutes. I was pleasantly zoned out when the overtemp
alarm went off. My first instinct was to throttle back to low power (I
was at about 5000 feet by then) to protect the health of the engine. GPS
showed that I was 6 minutes away from nearest airport and the engine was
running nicely when I shut down after landing. Was at at very low power
the whole time after the alarm since I was essentially
gliding.
After topping off with straight water and fixing my cap problem
I flew back to Florida with no problems and the engine did not suffer any
damage at all. If I had not throttled way back I'm sure it would
have been a very different story though.
Tracy