On 06/09/2010 12:16 AM, Frans Veldman wrote:
> If weather cooperates, we can tomorrow do some flight testing. I will
> let you know.
Flight testing complete. Could take off at 115%, without any
temperatures increasing during the prolonged climb out at 115%, with 75
knots. Water and oil stabilized at 90 C. This was with the cowl flap
halfway closed, and an OAT of about 20 degrees.
Can't believe what a difference it made to split up the two radiators.
(This is more than just "lowering" the oil radiator: they now don't
share any cooling air anymore). Amazing that just a 2 inch hole with
cold air for the oil cooler is doing much more than sending all the air
---From the water radiator through the oil cooler.
Now the oil radiator is gone from the duct, and I have surplus cooling,
I can slim down the cooling duct and tunnel, and probably gain a few knots.
I think the lesson to be learnt here is that the combination of oil
cooler and water radiator is too restrictive to the cooling air. You can
compensate this poor cooling by promoting air flow over the engine, but
this is more costly in drag terms than to just give the oil cooler a
dedicated air inlet of 2 inch.
Frans
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