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

Thu Sep 27 10:55:19 CDT 2012

Jack,

Good suggestion - I've watched that video before.  This is something I've
taken quite a lot of data on and done enough research and expert
consultation, so I think its safe to say that I likely have a dirty
injector.  I'm first going to clean both the fuel line and injector using a
solvent in an ultrasonic bath, then take more drastic steps if that doesn't
help.  Unfortunately, while I can easily get at the other injectors, I've
got to cut the plenum open to get at #3 - I'll cut it and make a nut-plated
cap, tho, so I can service it easier in the future.

The EGT on this cylinder is always ~100-120F higher than the others.  It
was causing high CHT's, but I've got those pretty much under control thru
plenum changes (it'll still get to 410F on climb out while the others are
in the high 390's).  I suspect once I get the EGT in line. it'll be the
coolest CHT of the lot.

Geoff

On Thu, Sep 27, 2012 at 11:44 AM, Jack Prock <jackprock at wavecable.com>wrote:

>   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 <geoff.gerhardt at gmail.com>
> *Sent:* Thursday, September 27, 2012 4:31 AM
> *To:* Velocity Aircraft Owners and Builders list <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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