Good News: Velocity
N755V received FAA airworthiness certification yesterday. Also
survived an intensive 4-hr inspection by a factory authorized insurance
inspector with a small list of minor items to attend to.
Not So Good News: Main
issue now seems to be cooling during ground operations, particularly
oil cooling, and the secondary temporary issue of mixture reprogramming
(again, after software update). With the wing root cooler in a pusher
configuration there is almost no oil cooling when standing still. So
running at significant power to adjust mixture allows little time to do
anything before reaching temp limits. Then, with cowl on, it takes
hours for it to cool down.
My expectation was for
enough natural convection cooling on the ground to handle low power
taxi operations. Earlier static running suggested that there would be
sufficient time, but I’m finding that; a) taxi maneuvering with brake
steering takes more power than anticipated, and b) the 3” thick, 16
fins/in. oil cooler core has almost no natural-convection cooling. Have
no good ideas at the moment how to improve this situation. Haven’t
gotten to high speed taxi yet to see if temps stabilize.
Tracy; can you tell me the
basics of your water spray system?
The in-cowl coolant rad
gets reasonable air flow because of negative pressure generated by the
prop aft of the cowl.
More later,
Al