REFLECTOR: Flight testing going well...18hrs in, new video

Thu Sep 27 11:56:27 CDT 2012

Geoff,

Do you know about these guys:
http://www.airflowperformance.com/html/site_html.html

What you are describing is not at all uncommon.  My first cyl peaks well
before my last.   This is a very expansive concept.  These guys can help
you.

Terry

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Geoff Gerhardt
Sent: Thursday, September 27, 2012 11:12 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Flight testing going well...18hrs in, new video

Scott,

Thanks for the info on reaming out an injector.  I looked at the price of a
new injector - wow!  I will be careful.  When I'm trying to go LOP, the
issue I have is that #3 is first to peak and when its at 50F LOP, the others
are at 20F or so (this difference varies with altitude).  When I get the
others to 50F, I can feel it starting to get a bit rough as #3 is likely
getting too lean.  #3 is always running leaner than the rest.  Hopefully a
good cleaning will help out, but if not, I'll try, as you say, "burnishing"
it out by twirling a smaller-size drill bit.

Geoff

On Thu, Sep 27, 2012 at 12:02 PM, Scott Derrick <scott at tnstaafl.net> wrote:

yeah the important point about EGT's is that their relative temps in
relation to PEAK are the important data points.  Probe location and wind in
the cowling can really skew the absolute temps, except for redline temps.
You don't want to run your egt's above red line very long.  

If your hot cylinder is still ROP when all the rest are well past PEAK and
running LOP that could cause the problem you are seeing.  Opening up the
injector would only worsen the problem.

BTW be very very very careful opening up the injector.  You basically
burnish not drill. The difference in size between sequential injectors say a
D12D to a D12E, one step in size, is less then the difference in size from a
numbered 72 to a numbered 73!  You always select a drill smaller than the
injector opening and then spin it by hand(NOT IN A DRILL MOTOR) a few times.
Very easy to open them up to much, and then your *****ed.  I put the drill
in a vise and spin the injector. Go from both sides, then blow out, then
inspect very carefully to verify no bits of anything are in the injector.

Scott

-------- Original Message --------
Subject: Re: REFLECTOR: Flight testing going well...18hrs in, new video
From: Jack Prock  <mailto:jackprock at wavecable.com> <jackprock at wavecable.com>
To: Velocity Aircraft Owners and Builders list  <mailto:reflector at tvbf.org>
<reflector at tvbf.org>
Date: 09/27/2012 09:44 AM

Hi Geoff,

Before you go chasing the EGT on one cylinder, you should watch
http://www.eaavideo.org/video.aspx?v=1316946190001

He gave a talk on EGT's at Oshkosh that was very interesting. It was about
the mistakes people make with EGT's and what

they really mean if anything. If your CHT's are fine, you should be fine. 

It is a bit long, but I highly recommend it before you start ripping things
apart.

Jack

From: Geoff Gerhardt <mailto:geoff.gerhardt at gmail.com>  

Sent: Thursday, September 27, 2012 4:31 AM

To: Velocity Aircraft Owners and Builders list <mailto:reflector at tvbf.org>  

Subject: REFLECTOR: Flight testing going well...18hrs in, new video

Guys, 

Flight testing is going well, I've got about 18hrs in.  I'm still not able
to just go out and fly - always little fixes and tweaks (that's the fun part
for me, tho).  I have learned, tho, not to immediately try to correct an
issue, but learn more about it first.  I've been chasing a hot cylinder and
have been trying to cool it with better airflow.  After reviewing data logs
and confirming it on my last flight, I now realize that its likely a
combustion problem.  The EGT for that cylinder is always high.  Because of
my aggressive airflow modifications, even in spite of that high EGT, the CHT
is ok now.  I'm going to pull out the injector nozzle this weekend and give
it a good cleaning.  If that doesn't work, I may try to ream it out a
little.  I tried to put an oil collection reservoir as I was tired of wiping
oil off the cowling, but it introduced too much back pressure, and all of a
sudden I had a bunch of oil leaks to deal with (a rather nasty surprise of
seeing oil all over the inside/outside of the cowling after a 2.5hr flight).
Got all those cleaned up and removed the oil recovery system.  I think I'll
try to vent the breather into the exhaust.

Other than those issues, its been going pretty well.  I've been playing with
fuel settings, altitude and efficiency.  I typically head up to 8-10,000'
and run LOP.  At 10k' I am usually ~150ktas, and 8gal/hr.  I love the
high-speed descent into the airport.  I report 10mi out to the tower and I'm
in the pattern in no time - I think they're getting used to me zipping in as
opposed to the C172's and warriors they're used to.

Here's a recent video I took taking off with a belly-mounted camera looking
back.  Its kinda neat in that it looks like I'm zooming the lens as I gain
altitude.  Yes, I know, it takes me a long time to get off the ground.  I
actually have another prop coming that might help.  A Cozy owner had a
left-turning Catto that he no longer uses.  Its a 64x76, mine's a 66x74.  I
suspect it'll get me off the ground much quicker.  He didn't want much for
it, so it'll give me a backup - I'll send mine back to Catto at some point
to get it repitched or just keep it for a long-range cruise prop as it is.

Geoff

(I uploaded it in high-res so make sure you switch to 1080p)

http://www.youtube.com/watch?v=JhNZBc-inbw

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