>My question regarding cooling on the ground is because all Rotax
equipped Europas are known to overheat very quickly on the ground. I
know some guys who say they do not overheat, but I have often observed
them taxiing very fast to the holding point to be sure they are aloft
before reaching the boiling point. Again the design of the Europa cowl
is not optimal but cooling in flight is very effective. On the ground
however it does not work properly. I am now convinced that the main
cause for this poor cooling on the ground is the propeller. Most Europas
are fitted with Warp Drive props or Airmaster hub Warp Drive blades
combination. Those blades are narrow at the root and not very much
twisted. Therefore they do not provide a lot of air flow where the air
inlets are located. On the other hand, most MCR are using the MT prop
whose design is just the opposite: very wide blades at the root and a
lot of twist which is a lot more effective ventilator. <
I think Remi's idea of using the cooler flap to increase cooling on the
ground and reduce it in the air is great. However, although I have a
Rotax 912S with Airmaster prop, I do not get significant cooling
problems on the ground even when the OAT is up to 30degC. Cooling and
cowl design seems to be one of those areas where even with identical
setups we all get different results. One thing that is certain with the
Rotax is that it has a tendency to get hot when the initial flight
testing is done in the summer months. I found that the engine took about
25 hours to run-in fully, after which the oil and coolant temperatures
dropped significantly.
Nigel Charles
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