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Al,
Temp readings are measured with my Advanced EMS,
factory calibrated and seem to be within 1 deg of accuracy. Water is measured at
the engine out water neck. Hottest point in the coolant system. The oil is
measured after the oil cooler at the oil filter bypass pad. Coolest part of the
oil system. I added an EM3 about a month ago just before my DAR inspection. I
only connected the EGT, WP, OP, O2 and serial connection to the EC2 for final
tuning and first flight. I plan to used the EM3 water temp to measure water
after the last radiator \ engine in. Also the EM3 oil temp to measure before the
oil cooler / engine out. Two CHT channels will also be used. One at the exit of
the first radiator and one at the entrance of the second radiator. This will
provide delta t information for all heat exchangers.
which
would suggest a very low coolant flow rate; much oversized
rad
I suspect both. Both rad's are dual pass but are
1.25" hose. Rad's and inlet size should handle a three rotor. At the time I
still had hope a three rotor renesis would be in the new RX7.
Either it has not come to steady-state, or perhaps the temp measurements
are suspect
I
discovered that with the cowl off (70-80 OAT) I can't get the oil warn
enough to stabilized the engine for tuning. Stuffing carpet in the inlets will
brings the temps up but slowly. With lower cowl only I can easily control the
temps for tuning. I have made multiple ground runs for two hours at a time with
a lot of time spent in the middle to upper rpm range. My airport neighbors
willing to do just about anything to get me in the air
ASAP. :)
What accounts for
the big change with and without the cowl?
Airflow across the radiators. They sit outside the
engine profile and back against the firewall. They get a lot of air without the
cowl. With full cowl I suspect they see very little if any airflow. They do
better when taxing but I don't remember what I was seeing or how heat soaked it
was before taxing. If my strange tuning issue gets resolved I hope to have
flight data to present at the Spring Rotor Fest.
So
the first rad removes most engine coolant heat. Oil / water exchanger transfers
oil heat back to coolant. Second rad removes the oil heat + from the
coolant. Water rad's should have a very high delta t. At least that's how I
think it's working. The additional measurements points will be interesting
to see.
Bobby
(Working on Spring Rotor Fest announcement. Should have
it out this week.)
I have the
largest (ECD54-329) plumbed between two 400 ci water radiators. I can tell you
it is very effective. With my cowling off, extended full power ground runs I see
oil temp trailing water temps by 40-50 degrees.
Where are you taking
the temp measurements for the oil and water? Under these conditions, the water
is heating the oil. If heat is being transferred from oil to water, the water at
the exit of the first rad would need to be 60-70 degrees lower than the inlet;
which would suggest a very low coolant flow rate; much oversized rad; or
something suspect. Either it has not come to steady-state, or perhaps the temp
measurements are suspect. Or; there is something suspect about my understanding
of setup.
With lower
cowl only, same conditions, the oil tracks the water a little closer. 20-40
degrees. With full cowl the temps come up together and stay together after about
170 degrees.
What accounts for
the big change with and without the cowl?
Al
G
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