REFLECTOR: Update on my Subaru installation

Sat Mar 28 02:09:30 CDT 2009

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 Balic 
Sent: Friday, March 27, 2009 7:42 PM
To: 'Velocity 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

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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

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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..

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