Turbo RV-7 First Flight

rv6ejguy · #1 02-22-2011, 10:34 PM

It was a cold, grey day at Springbank Airport CYBW this afternoon but this was the day that the turbocharged Subaru powered 7 C-FKRZ built by RV guru Ralph Inkster finally broke the bonds of earth. Sounded great and performed well at reduced power settings for the 45 minute flight.

We didn't have good camera or video equipment handy unfortunately but I'll try to post some photos tomorrow.

That's builder Ralph with the hat and Ted, our intrepid test pilot.

My first attempt using Photobucket so please excuse the sizing.

http://s1105.photobucket.com/albums/...v720110020.mp4 Short video of the Subaru purring away, shot with an old Canon A60 which was all I had handy.

Mike S · #2 02-22-2011, 11:45 PM

Would I be correct in assuming you had something to do with the engine???

rv6ejguy · #3 02-23-2011, 12:06 AM

I advised on many aspects of this FF package, turbo, EFI, intercooler, rads, ducting etc. Ralph built the plane for a customer, Shane Getson.

The engine is an ex Eggenfellner STI block with the Eaton blower mess removed and replaced with a custom matched Garrett T4/ T3 hybrid turbo. The factory EFI was replaced with an SDS EM-4 4F driving the factory coil on plug units and injectors.

Uses an MT prop and Egg Gen 3 gearbox.

Mike, are you sure you are not envious of our beautiful weather this time of year? It was a balmy -17C at 1500 AGL.

Jerry Cochran · #4 02-23-2011, 12:12 PM

Ross,

What kind of HP@Rpm do you expect? Is that Gen3 gearbox going to be bulletproof? What kind of cooling config is he using?

Of course, you won't need no stinkin' cooling for awhile.. it looks like with that blue cold you have there...heheh

flyboy1963 · #5 02-23-2011, 01:23 PM

....what kind of speed and efficiency can you get with the cowl totally sealed?

congrats on the flight, and the nice power package. I flew behind a Sube glastar on Vancouver Island.....ran like a swiss watch.
One lever. On/off. repeat as necessary.

If you don't like the weather in southern Alberta, wait a day, right Ross?
....( okay, it'll still be winter tomorrow I guess!...but the asphalt will be clean!)

hey, why do all these RV drivers, test pilots and owners wear those silvery coloured helmets all the time?

oh, I see now.

(my hair is also very 'mature'.)

perhaps we should do a poll?

rv6ejguy · #6 02-23-2011, 01:48 PM

Quote:

Originally Posted by Jerry Cochran

Ross,

What kind of HP@Rpm do you expect? Is that Gen3 gearbox going to be bulletproof? What kind of cooling config is he using?

Of course, you won't need no stinkin' cooling for awhile.. it looks like with that blue cold you have there...heheh

The owner had this built to go fast. The engine is easily capable of making 250hp at 5000 rpm and 50 inches which is 50 hp and 1500 rpm below the stock engine power rating. Randy Crother's similar machine could easily exceed redline in level flight at power settings well below this. This is really about how much fuel you are willing to burn. The climbout was around 1000 fpm at 120 mph running only 30 inches and 4800 rpm. It's doubtful we'd need to run more than 4500 rpm and 40 inches to true 200 knots at say 12,000 feet.

For the most part, most Gen 3 boxes have been holding up ok at the 160-200hp level aside from some annoying front seal leaks. Randy has run his hard above these levels and it's holding up. A bit of an unknown. A few bearing problems have surfaced and issues with the input shaft snap rings on a couple boxes but these do not seem to be across the board.

This aircraft has substantially different radiators and much more area than any other Subie RV flying, ditto on the oil and intercoolers. We don't expect any thermal problems in hot weather but only flight testing in the summer will prove this. Everything ran way too cold on the first flight so we need to make a few changes to keep Ted and the engine warmer.

rv6ejguy · #7 02-23-2011, 02:09 PM

Quote:

Originally Posted by flyboy1963

....what kind of speed and efficiency can you get with the cowl totally sealed?

The overall cooling drag may be higher than on a Lycoming due to the margin needed to cool this more powerful engine and the intercooler drag but up high this is easily offset in the thinner air. The cowling uses nearly stock cheek inlets for the rads, the chin scoop for the oil cooler and NACA ducts to feed the intercooler and third internal rad. Discharge air for the intercooler and internal rad are carefully channeled to the cowl exit to minimize turbulence and an offsetting pressure rise within the cowling. Ralph did a very slick job with all this.

Jerry Cochran · #8 02-23-2011, 02:11 PM

Ross,

What kind of fuel burn at HP settings/speed similar to Lyco do you expect?

Also, do you expect this setup to perform equal to or better than the Lyco turboed that has been mentioned here lately?

What's the W/B look like?

Either setup sounds like a lot of fun.

rv6ejguy · #9 02-23-2011, 02:37 PM

I can only hope that the performance parallels Randy's 7A. Fuel burn was a little lower for the same TAS as a Lycoming above 10,000 feet.

Speed wise, the engine makes more hp than the Lycoming so the Subaru is likely to be faster at all altitudes. It depends a lot on how much boost each engine is running. The Lycoming can make more power than it currently is too. Randy was "well over" ahem 200 knots true below 45 inches and 4500 rpm I believe in the 10000-12000 foot range. No point in cruising around low with a turbo and a likely 3000 fpm climb rate to get you up there fast.

W&B was pretty similar to a Lyco/ Hartzell C/S. The MT is substantially lighter up front so it offsets the heavier engine package. Ted said it flew like an RV just with a lot less vibration than he was used to. Had a couple of funny ranges at low rpm on approach, perhaps from the prop driving the engine at low MAP. Also had the usual Gen 3 rum, rum noise at higher rpm. Others are investigating gear ratio changes to eliminate the latter.

I agree, turbos make any aircraft more fun!

Kevin Horton · #10 02-23-2011, 02:50 PM

Very interesting aircraft. Congrats.

Quote:

Originally Posted by rv6ejguy

Ralph built the plane for a customer,

I must clarify for our US viewers that the regs in Canada differ from those in the US. In Canada, it is perfectly legal for a builder to contract with someone else to do some or all of the work on his amateur-built aircraft project, as long as the builder retains overall control and responsibility for the work that is conducted by the contractor. This effectively legalizes the "hired gun" folks that would be hiding under the radar in the USA.