What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Turbo Subies in Formation

R

rv6ejguy

Well Known Member
Today, before weather rolled in, we managed to squeeze in a formation flight with the two turbo Subaru powered RVs based at Springbank Airport (CYBW) and a Lycoming powered RV7A acting as photo ship. I shot stills and video. Here are a few shots.

The Yellow 6A has the 2.2 engine and the blistering fast silver 7 has the 2.5 engine.

Ralph Inkster piloted the photo ship (he also built the silver 7). My Dad was flying my yellow 6A and Ted Sorensen piloted the mighty 7 owned by Shane Getson. Shane is anxious to have his aircraft delivered up north to its new home as the restrictions have been lifted and all the paperwork is now in order. We'll miss hearing its distinctive sound and blinding speed around Springbank.

IMG_2276.jpg


IMG_2297.jpg


IMG_2365.jpg


Lots of fun doing this shoot even though the air was a bit bumpy.

The 7 with MT prop and cleaned up aerodynamics is vastly superior in performance to my tired 6A with the smaller engine and IVO prop. In fact, with MAP limited to 33 inches on the 6A, Ted was running about 10 inches less to stay in formation. My Dad could not catch the the O-360 FP 7A photo ship on climb out- time to get that -10 done.
 
Last edited:
Thanks guys. We are having lots of fun with these two aircraft as you can see. I'll try to get the video edited and up next week sometime.
 
Last edited:
Ted opened it up "a bit" during testing. It takes something less than 40 inches to exceed Vne in level flight at under 8000 feet. The engine runs about 58 inches in stock form so you can see the huge power potential of this engine. For sanity and safety sake, MAP is limited to 40 inches for Shane, the airplane's owner.
 
Ross....

Unless i missed it...what are the details on the RV-7 STi setup? Is it a one-off design? Retooled Egg set-up? Other? What redrive is used? engine mount? Where is the radiator? Is there a web link with these details?

The 2.5 STi turbo setup always seemed to me like an ideal starting point for aircraft application. I never fully understood why Jan abandoned it so quickly a few years ago in favor of the heavier H6. But then there were any number of things about the whole Egg phenomenon that left me scratching my head...

And...thead-drift alert...my own 2007 STi car just required a new block and turbo at 81K miles...under the extended warranty I purchased (thank God) when the car was new. Very strange. While I am probably not the most gentle of drivers, the engine had regular oil changes, always ran Mobil One, and had regular service. I was led to understand there was a crack in the tube that draws oil up from the oil pan that may have been a manufacturing defect. I could never have imagined something like this given the Subaru reputation for long-lived engine life.

Dan
Chicago
RV-9A tail kit still in the box...
 
RV-7 STI setup

This project started as one of Eggenfellners packages. We had concerns with some of the component & their setup, so came up with our own solutions. Items retained from the original are longblock, mount, & redrive (although the Gen2 did get replaced with a Gen3). Our solutions involved solving the cooling issue by upgrading the 2 small rads with units approx twice the size ot the originals, we also added an equivilant sized third rad on the firewall that could be controlled by separate water valve (as yet we haven't had to use it). The third rad gets it's own air supply by the naca duct you see on the side of the cowling & air is exhausted thru it's own dedicated exh ducting below, this is to not degrade the airflow thru the main radiators. The next issue were ignition & throttle body as both were original car components, a manual throttle body was fitted and one of Ross's SDS injection/ignition systems was installed. The original Supercharger presented a number of issues that we didn't like, so a custom turbocharger was mounted, with reworked exhaust, oil supply, and reworked charge air circuit... and... reworked intercooler with devoted air/exh plumbing similar to the third rad setup. Even alternator mounting got attention with custom pulley sizing, alt upsizing & robust mounting system. These are the major points, there were MANY minor points that also were addressed. We knew we would get the power, the bigger goal was to get a reliable setup. Time will tell if we were successful.
This package was installed on a stock 7 quickbuild airframe, so we are very reluctant to see 'what it'll do'.
 
Oil Temps

Great Video Ross. Congrats on achieving a real milestone in the alternative engine debate.

I should probably know this but what oil temperatures are you happy with and where do you measure. I have the NSI package which uses a sandwich block between the engine and oil filter to direct oil to and from an oil/coolant heat exchanger. The oil temp sender is in this block and may be affected by the cooled oil - probably need to check its exact position.

My engine is only an atmo SOHC EJ25 but I plan to start experimenting to see if I can reduce the cowl outlet substantially from its current 130 square inches.

Many thanks

Rupert
 
djvdb63 said:
Ross....

Unless i missed it...what are the details on the RV-7 STi setup? Is it a one-off design? Retooled Egg set-up? Other? What redrive is used? engine mount? Where is the radiator? Is there a web link with these details?

The 2.5 STi turbo setup always seemed to me like an ideal starting point for aircraft application. I never fully understood why Jan abandoned it so quickly a few years ago in favor of the heavier H6. But then there were any number of things about the whole Egg phenomenon that left me scratching my head...

And...thead-drift alert...my own 2007 STi car just required a new block and turbo at 81K miles...under the extended warranty I purchased (thank God) when the car was new. Very strange. While I am probably not the most gentle of drivers, the engine had regular oil changes, always ran Mobil One, and had regular service. I was led to understand there was a crack in the tube that draws oil up from the oil pan that may have been a manufacturing defect. I could never have imagined something like this given the Subaru reputation for long-lived engine life.

Dan
Chicago
RV-9A tail kit still in the box...
Click to expand...

You can search "Subaru turbo" here on VAF and see some other posts and video links.

With regards to the STi engine, there were somewhat widespread issues in the 2008-2009 model years with improper ECU calibration leading to piston failure, cracks in the oil pickup tubes or complete fractures leading to a loss of oil pressure and engine seizure and too close bearing clearances leading spun bearings. The problem was bad enough that Subaru USA put a stop sell order on STis for several months until investigation into the causes of numerous warranty claims could point engineers in the right direction for fixes.

These tarnished Fuji's relatively good reputation as far as engine reliability went. Given the massive testing done on automotive designs and strict process control it is hard to believe these problems made it into production but equally puzzling is how Fuji failed to correct design problems with head gaskets, clutches and rear wheel bearings for about a decade. It just goes to show that nobody is perfect.

The engine problems seem to be corrected now and the STi is probably the best automotive choice out there for use in RVs- relatively light, the right shape and has a good power to weight ratio.
 
clarkefarm said:
Great Video Ross. Congrats on achieving a real milestone in the alternative engine debate.

I should probably know this but what oil temperatures are you happy with and where do you measure. I have the NSI package which uses a sandwich block between the engine and oil filter to direct oil to and from an oil/coolant heat exchanger. The oil temp sender is in this block and may be affected by the cooled oil - probably need to check its exact position.

My engine is only an atmo SOHC EJ25 but I plan to start experimenting to see if I can reduce the cowl outlet substantially from its current 130 square inches.

Many thanks

Rupert
Click to expand...

On mine I measure OT in 2 places but downstream of the cooler is what we are concerned with. I use an oil thermostat (no water T stat) and generally see 92-95C in cruise on a 20-25C day, might see 105C in the climb on a warm day. I think the STi runs cooler than that. We both run air to oil exchangers. Oil temps are interrelated with coolant temps in these engines to a large degree so if coolant runs hot, oil tends to as well.
 
Oil Temps

Thanks Ross

The NSI probe is upstream of the heat exchanger and the vendor's top of "normal" temp is 235F (113C). Probably directly tied to the top of normal for coolant which is 220F.

I will instal another sensor in the sump and hold the oil below 220F in the climb to lessen the chance of spinning a bearing. Cruise temps are a non-issue, in fact without the thermostat it is difficult to get the temp up to 140F even with full power. Then again the naturally aspirated engine is only making a bit more than 160 hp (good for about 165 KIAS at 2,000' in the 9A).

Hopefully a smaller and so less draggy cowl outlet will result in a few more knots.

Rupert
9Ainflight.jpg
 
I wouldn't be too concerned about transient oil temps getting to 230F with synthetic oils.

165 knots is not shabby with an atmo EJ25.
 
You must log in or register to reply here.
Back
Top