REFLECTOR: Resolved!: Oil temp issue (and heat in the nose)

[Hiroo Umeno]

So far, I haven't seen much effect on the airspeed but mine is a bit of a dog right now.  Wings aren't exactly clean, wing bolt holes are still uncovered, there are a lot of odd bits hanging off the airframe, etc.

On a good day (when I don't redline the #6), I can coax 160kts TAS out of the dog full-bore but it is normally happy putzing around at 120Kts or so with throttle pulled back quite a bit.

Now that the concept is sound and it has a positive results, I can experiment and find a solution that will work better.  I figure, when I start speed tuning, I can fair it in better and create a bit more gentler ramp.

For now, it is a "proof of concept" and it definitely did its job.

Hiroo

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of gpoole
Sent: Tuesday, July 10, 2007 2:44 PM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Resolved!: Oil temp issue (and heat in the nose)

Hi Hiroo....took a look at your pix on your exit in the lower cowl....don't want to "wee on your bonfire" but, in an attempt to be constructive; that's a pretty serious angle you have got over a very shot distance old mate!  Reminds me of a mini-speed brake. I would expect it to cause a fair bit of drag given the lack of a gentle transition. Thought it might work on a slow STOL aircraft but on a Velocity I'd reckon your penalising yourself......be interested in what others on this list think....

Greg in Sydney

gregpoole at saaachapter11.com<mailto:gregpoole at saaachapter11.com>
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Hiroo Umeno
Sent: Wednesday, 11 July 2007 3:08 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Resolved!: Oil temp issue (and heat in the nose)

I got a couple request for information on how I fabricated this so rather than respond individually, here is the info with pictures.

I got a piece of florist's foam from a local craft supply place.  It is green colored and rather brittle.  According to my wife who suggested it, it is the "soaking type" that absorbs water.  When you go at it with a utility knife, they pretty much turn to dust crumbling.  It is, by far, the easiest stuff to sculpt complex shapes with.  Once I get the rough shape done, I shoved the thing up the duct exit to fine-tune the shape.  Then, I cover the whole works with duct tape, tape the fuselage areas around the outlet, then lay up a couple layer of BID.  Let stand, peel apart, cut, trim...  You get the duct exit to an exact fit.

It extends about 3" beyond the fuselage bottom and provides a low pressure "suction" down the duct.  Took me about 2 hours working time to fashion the arrangement and I am quite happy with the results.  For now, it is fixed with four sheet metal screws for testing but I will glass it in for smoother look when I get the chance after the flying season.

Hiroo

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Hiroo Umeno
Sent: Monday, July 09, 2007 9:06 AM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Resolved!: Oil temp issue (and heat in the nose)

I did my first test flight after installing the nose oil cooler outlet baffle yesterday.  It was another beautiful 75degree day in Seattle, much unlike my last flight when I couldn't climb for 5 minutes without busting redline on oil temps.

With the oil cooler outlet baffle, at no time during the flight, the oil temperature redlined.  In fact, it did not even get into the yellow zone and stayed comfortably in the high green (Yellow = 220F, Red = 230F).  That was with me flying at sustained 98Kts or so for a while.  Previously, the only way to keep below Red was to consistently fly 105Kts or more and avoid turning right for more than a minute or so.  Much improvement.

Another side-effect is that the heat in the nose appears to have been mitigated quite a bit.  Previously, after flying about an hour or so, I would start feeling rather warm in the foot-well and if the sun is out (like it was yesterday), it gets quite warm in the cockpit.  With the nose air duct outlet installed, it stayed comfortable through the 3.0 hour flight which included sustained "slower" flight and pattern work.

Now, my #6 still runs fairly hot and that kept me from climbing aggressively or doing any high-performance runs.  Next thing to fix.

The brake has been bled free of air and feels a bit better.  Still not as "assertive" as I like but that may be how it is with this set.  I am considering changing to all-metal tubing from part-metal, part Nylaflow arrangement I have now.

Hiroo


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