Congratulations Al.  I'm glad to hear you got your paperwork.  Can you

set up a blower to provide oil cooling until you get your mixture tuned

in?\

 

When the plane was still home and the wings weren’t on, I had a centrifugal blower setup which worked fine.  With the cooler installed in the wing, that is more difficult – really nothing to connect to. I will try setting a big fan under the wing at the inlet and see how much that helps.  Another brief run or two should get the mixture dialed in pretty well.

 

2.     Possibility of a permanent fan to pull air through - but I would be a bit concerned about it windmilling at cruise.

 

Ed.  Just not enough space in the wing for a fan.  I’ll defer any decision on a permanent change until engine tuning is completed and we have a bit more taxi time; including some high speed.  The expectation is that cooling will be good once there is some lift under wings.  

 

After a brief warm-up; I was able to maneuver around the hangar, taxi about 3000 ft downwind to the end of the taxiway, and then return to the hangar before oil temp got to 220F.  Outside air about 68F.  The test will be to be able to taxi, do runup checks, and get to liftoff speeds with some margin.

 

Everything is on hold today as I strained my back moving the airplane in and out of the hangar.  Because of other planes in the big hangar, this takes a bit of maneuvering, and the plane is heavy now that is fully assembled and has 40 gallons of fuel in the tanks.

 

Al

 

 

> 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

>