REFLECTOR: Repairs

[Dave T Nelson]

I'm not going to debate this, but I stand by what I said and what dozens of
Long-ez and Varieze pilots and owners have experienced.  I would also note
that after hundreds of flight hours with this setup, I can confirm the lack
of any exhaust residue on the inside of my cowl.  Because I have a three
bladed MT prop, I do certainly get exhaust residue on the prop.  I've been
very careful to watch for any heat damage to the prop (the earliest sign
you'll get is a whiff of orange peels).  There has been none.

Please choose your own installation and focus on safety.

Dave



   1. Re:  Repairs (Scott Derrick)


----- Message from Scott Derrick <scott at tnstaafl.net> on Fri, 21 Sep 2012
08:42:56 -0600 -----
                                                           
      To: Velocity Aircraft Owners and Builders list       
          <reflector at tvbf.org>                             
                                                           
 Subject: Re: REFLECTOR: Repairs                           
                                                           


Hmmm.. I understand augmentation. but just ending the stack inside the
cowl, may augment a bit but the potential to get exhaust gas inside the
cowl is to great.

General to augment you have a tube inside a tube.  I don't see that.

If you look at the picture from the link below I first had the exhaust exit
without the forward bump on the cowl. I added the bump or flare in front of
the exhaust because the air was flowing into the cowling and defeating the
cooling.  Maybe if Lou built up a flare and tube for his exhaust to exit
through he could prevent exhaust gas form entering his engine compartment?



-------- Original Message --------
Subject: Re: REFLECTOR: Repairs
From: Dave T Nelson <dtnelson at us.ibm.com>
To: reflector at tvbf.org
Date: 09/21/2012 08:07 AM



      Many EZ types have the exhaust end inside the cowl.  I've been doing
      that for many years now on my Velocity.  It actually works quite well
      and can increase overall cooling.  The exhaust gas is at such a
      greater velocity than the air around it that  it actually acts as an
      augmentation and "pulls" air out of the cowling.

      Because your exhaust exits through the bottom of the cowl directly
      down tangentially into the slipstream instead of exiting aft in
      parallel with  the slipstream, you probably are getting some of that
      hot exhaust gas back into the cowl.

      One other factor to consider is the large drag you are creating
      exiting your exhaust down instead of aft.  It's a very "draggy"
      setup... I probably gained close to ten knots when I got rid of it.

      Dave



      ----- Message from Scott Derrick <scott at tnstaafl.net> on Fri, 21 Sep
      2012 07:18:20 -0600 -----
                                                           
      To: Velocity Aircraft Owners and Builders list       
          <reflector at tvbf.org>                             
                                                           
 Subject: Re: REFLECTOR: Repairs                           
                                                           

      Wow, I've never heard of ending he exhaust "inside" the cowl! That
      sounds bad,  I definitely want my exhaust outside my engine
      compartment and away form the plane!

      here's a picture of my left stack.

      Scott


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