<VV> An interesting thing.....

[Dave Morris "BigD"]

I'll concede you are more correct about the Pietenpol.  What I should have 
said was that the Pietenpol was one of the first airplanes to popularize 
the use of Corvair engines decades ago.  People are still building them and 
putting Corvairs on the front.

I'm not sure I'll concede the point on the purpose of painting the outer 
half of the pushrod tubes until I have a chance to go out to the hangar and 
look at my Finch book.  But I do not believe he stated it as being 
primarily for cooling the oil, because there are more sophisticated ways of 
doing that with external oil coolers.  I am pretty sure that was in a 
section entitled "how to prevent oil leaks", but of course, my memory could 
be off.  Of course if it reflects heat, it is also keeping the oil cooler 
at that point in the system.  But I would think if your purpose was to 
lower the oil temps by 10 or 20 degrees, you'd probably use an oil 
cooler.  I just know that virtually all of us who are rebuilding Corvairs 
for our airplanes are painting them white.  Of course, the white paint is 
most effective at reflecting visible light, and heat is a different 
wavelength, so it is possible that our white paint is not doing that great 
a job at infrared wavelengths.  But it is a sound principle, and those who 
have flown airplanes that way say that, at the very least, it doesn't hurt 
anything and probably helps.

I am a bit surprised that Finch doesn't seem to have much of a following in 
this group.  I found his book to be full of practical ideas and easily 
readable.

The idea of coating the exterior with a high temp RTV is interesting to 
me.  I wonder what sort of insulative properties it really has.  I like the 
idea of wrapping the tubes with a heat shroud, too.  But that may be 
killing gnats with a cannon.

Dave Morris

At 09:57 PM 2/4/2005, you wrote:
>I don't usually get too (to,two?) picky...but:
>
>From: "Dave Morris" <BigD@DaveMorris.com>
>
> >  In fact, the Pietenpol was maybe the first airplane designed to
> > be used with a Corvair engine decades ago. >
>
>Pietenpol Aircampers first flew in 1929 with Model A Ford engines. They were
>not  originally designed to be used with a Corvair engine.
>
> > We paint the pushrod tubes white because Richard Finch in his book "How to
> > keep your Corvair alive" suggests that as a way to prevent leaks around
>the
> > o-rings.
>
>No no no. The white ceramic paint is on the tube so that the heat from the
>exhaust manifold passing nearby is not transferred to the oil returning to
>the sump via the tubes. It is to keep the oil cooler, nothing to do with
>leaks.
>
>yea, Vairily ... Shaun
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