REFLECTOR: Update on my Subaru installation

Sat Mar 28 08:34:59 CDT 2009

Hi Chuck- 

Thanks fro the good advice- I have added a wetting agent to the coolant, so
that should (might) improve cooling efficiency- also- I am not using the
NACA scoops for engine cooling- I am using one of them to bring in air for
the turbo intercooler- the other one is to bring in air for the engine oil
cooler/ PSRU oil cooler stack and a little bit for the 95 amp alternator,
and to dump down on the firewall / turbocharger area. The turbocharger and
exhaust are wrapped to reduce radiant heat load inside the engine
compartment. I have a belly mounted ram air scoop- see early construction
picture (hopefully) it is very similar to Dave Bertram's scoop that he is
using on his V8 powered Velocity- and he has reported no cooling problems
and is making about 100 more HP than I am, so I am confident that it will
cool for me- I have an electric fan on the radiator to assist in ground
operations- only testing in the fine Texas heat will tell if it is all
sufficient, but I intend to do just that this summer!

Alex

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Chuck Harbert
Sent: Saturday, March 28, 2009 2:10 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Update on my Subaru installation

Alex, my experience was that I would need my PSRU oil cooler ahead of of my
engine oil cooler because it would better to make sure the PSRU has cool oil
going to it to prevent the oil wedge on the gears from failing and resulting
in galling which will eventually lead to failure. This is how these units
generally fail. The btu cooling load for the psru should be small, so it
shouldn't hurt the cooling of the engine oil if that cooler is in front. It
might be fine to have it behind, but just monitor it.

Mazda's are very hard to keep cool because they more like a 2 cycle which
has a very hot exhaust stream, but all turbo charged engines make lots of
heat, especially when running continuously at high horsepower.

Your overhead naca ducts will not work that well during climbout when the
airspeed (pressure) is low and power is high, so watch your temps closely.
Unfortunately, ground testing and taxi testing does not simulate the
climbout load, but if you have cooling problems during these phases, you're
likely to have a problem. Like I said, Al Gietzen is really good for cooling
problems, but maybe you'll be fine. 

I originally was using Evans pure glycol, but they warn you not to use it in
aircraft because it can sludge up in very cold weather at altitude, so
glycol/water might be best with a high pressure cap (20 psi) cap. I always
wished there was a way to have dual ignition that was self energized
(magneto), a carb and mechanical fuel pump to supply fuel, but dual
"independent" electrical supply to these key items is the best way to go.

You're going to have a sweet plane when your done which is going to be
speedy because of the turbo. 

Chuck H

From: Alex <mailto:velocity_pilot at verizon.net>  Balic 

Sent: Friday, March 27, 2009 7:42 PM

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

Subject: Re: REFLECTOR: Update on my Subaru installation

Hi Chuck-

Thanks for the kind words- I have spoken to the Swings about their
experience with the Subaru- they were using the stock ECU which is not
suitable for aircraft use in my opinion- Tracy Crooks equipment is purpose
built, simple and does a great job.  I have an oil cooler on the Tranny- it
is mounted down stream of the Engine oil cooler, although I might swap
positions if I find that the engine cooler is just cooking the tranny
cooler-  see video-just figured that it was more important to have cool
engine oil than PSRU oil- I have a temp sensor on the PSRU to keep an eye on
things though. I have heard that the Mazda engines are notoriously difficult
to keep cool on the ground, and their high RPM make life difficult on the
gear box too. Right now I am using water/glycol but might go with the
non-aqueous coolants that some folks are running to avoid pressure problems
in the system- I do have a 14 psi cap on there and a pressure sensor for the
coolant system so I can keep an eye on things.  Will be doing a lot of
extended high power ground testing before any flying is considered for sure.

I have a few things to get done before I get flying- namely get my home
brewed retract panel working, get my 2 battery/2 alternator electrical
system connected up just right, and buy a flight prop- so probably will not
be getting airborne until at least the end of the summer (with the recession
and all) 

Alex

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Chuck
Sent: Friday, March 27, 2009 3:22 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Update on my Subaru installation

I went with the almost Subaru 6, but Dwayne told me a few stories about
their exciting experiences when it went into "limp home mode". Sounds like
you've got it handled with Tracy's system. I had a turbo-Mazda rotary 20B (3
rotor) which was a problem due to excessive heat and gearbox reliability. I
ended up with more radiators for both the engine and gearbox. You might want
to have an oil temp gauge on the outlet of the gearbox to make sure it stays
under 220F. I hope you don't get engine overtemp problems on the first
flight like I did, but be ready to get back on the ground if you do. Al
Gietzen (Mazda 20B) is the expert on oil/water cooling for non-AC engines if
you need a resource. 

Looks like a beautiful installation and we'll be watching for you to take
that first flight. Good luck.

Chuck H

  _____  

From: velocity_pilot at verizon.net
To: reflector at awpi.com
Date: Thu, 19 Mar 2009 10:44:28 -0500
Subject: REFLECTOR: Update on my Subaru installation

Well, after a lot of additional work- and parts fabrication,  I replaced my
previous engine control unit (supplied by our friends at Crossflow) with an
excellent ECU from Tracy Crook / Real World Solutions- I can recommend him
highly- he was always available to help and re-program the unit to make it
work perfectly- I have a new video up:
http://www.youtube.com/watch?v=gW1YtHq9ZtY - I still need to do the fine
tuning programming, but should be taxi testing in a month if I can get out
to the hanger more that a couple of hours a week.... now just need to save
up for that Vesta prop I have been eyeing..

  _____  

_______________________________________________
To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20090328/149fe4d9/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Belly Scoop low res.jpg
Type: image/jpeg
Size: 100161 bytes
Desc: not available
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20090328/149fe4d9/attachment-0001.jpg>