X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtai11.cox.net ([68.230.241.48] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1099291 for flyrotary@lancaironline.net; Wed, 10 May 2006 13:43:59 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.48; envelope-from=ALVentures@cox.net Received: from BigAl ([72.192.132.90]) by fed1rmmtao03.cox.net (InterMail vM.6.01.06.01 201-2131-130-101-20060113) with ESMTP id <20060510155917.RSEN19317.fed1rmmtao03.cox.net@BigAl> for ; Wed, 10 May 2006 11:59:17 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Oil cooling Date: Wed, 10 May 2006 08:59:25 -0700 Message-ID: <000001c6744a$b6547cb0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C67410.09F5A4B0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C67410.09F5A4B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable 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?\ =20 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. =20 2. Possibility of a permanent fan to pull air through - but I would = be a bit concerned about it windmilling at cruise. =20 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. =20 =20 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. =20 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. =20 Al =20 =20 > 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. >=20 > 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. >=20 > Tracy; can you tell me the basics of your water spray system? >=20 > The in-cowl coolant rad gets reasonable air flow because of negative > pressure generated by the prop aft of the cowl. > More later, =20 >=20 > Al >=20 =20 =20 ------=_NextPart_000_0001_01C67410.09F5A4B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

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?\

 <= /font>

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.

 <= /font>

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

 <= /font>

 

> 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

>

 

 

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