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Turbo RV-7 First Flight

R

rv6ejguy

Well Known Member
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.

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

My first attempt using Photobucket so please excuse the sizing.

rv6ejguy
Short video of the Subaru purring away, shot with an old Canon A60 which was all I had handy.
 
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Congrats!!!!!!!!!!!!

Would I be correct in assuming you had something to do with the engine???
 
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.
 
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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
 
Imagine at those temps?

....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? :)
 
Jerry Cochran said:
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
Click to expand...

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.
 
flyboy1963 said:
....what kind of speed and efficiency can you get with the cowl totally sealed? :)
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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.
 
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.
 
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.:cool:

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!
 
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Very interesting aircraft. Congrats.

rv6ejguy said:
Ralph built the plane for a customer,
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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.
 
Kevin Horton said:
Very interesting aircraft. Congrats.


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.
Click to expand...

The thinking is that experienced shops can turn out safer work than some amateur builders do. I've seen some evidence of this. Some people just do crappy work while others turn out pure art. The other side of the coin is that many people want a cool, non factory plane like an RV or Lancair, have the money but maybe no time or talent to build it.

I must say that we are very fortunate in Canada to have the most open regs here for amateur built aircraft in the world. Safe without be ridiculously onerous as in some countries which have illogical requirements.
 
Thanks all for the comments on the Turbo STI RV7 project. Also thanks to Ross for sharing his hard earned experience in working thru this build.

We've made 2 flights & have just over 1.0 on the clock, & delighted at the results so far. Engine is running beautifully. Only concerns, temps too cool (daaa! OAT -18C, what do we expect!) and a slight heavy right wing. We're hoping this no snag trend continues. We are progressing in small conservative steps.

We've limited MP to max 30" for now, running lower for the most part which means we haven't advanced the throttle much if even half. With reduced throttle we've seen 14ooFPM at 110MPH/2500RPM/?MP. Cruise 5200PAlt/24.8"MP/2320PropRPM/6.9GPH(?)/EGT 1590F(running too lean I think!)/O2 sensor 13.4/138KIAS--that's around 160KTAS! This is all preliminary stuff for now, we have to figure out to properly control this engine before real results come out.... but the potential....
 
Sorry I couldn't observe the 2nd flight Ralph. Yeah, 1590 EGT is higher than we'd like to see. Maybe I'll try to swing by tomorrow and retune the EFI slightly richer or look at adding some more ignition advance. Good speed and FF numbers compared to my old ship.
 
Re; builder assist in Canada - I'm just glad to be able to help out owner/builders that are in year 5 of a planned 2 year project...
 
Flutter Concerns

While we are talking turbos here, I see Van's has brought up the TAS/ flutter concerns at high altitude again. Anyone contemplating turbos should read Ken's excellent article on these matters. You need to understand these concerns and operate the aircraft accordingly. Flutter can instantly kill you.

Van's and everyone else here on VAF does not want to hear about a structural failure caused by flutter with someone pushing the limits too far. It can be very easy to exceed limits on 6s especially over 10,000 feet with a turbo and not much harder on a 7, 8 or 10.

I've operated my turbo 6A since 2003 with no issues but run rather conservatively these days due to fuel costs. Van's limits ensure a good safety factor so stick by them. If you must have a lot more speed, consider a Rocket which has a higher Vne.
 
Ross,

Thanks for putting this on the site, I was quite tickled to see the video, and the pictures of all the fun you guys have been having in our spring like weather.

Hello to everyone else,

Firstly I am taken aback by the interest in our little project, as it did not seem like we were doing anything too special at the time, just making incremental improvements to a non conventional engine attached to a fantastic airframe. However upon further reflection, and sum of the improvements have made for what has the potential for one heck of an airplane!

For those of you curious enough to wonder why a guy would have someone else build most of their airplane for them, I can only provide you with the insight as to why I went that route. I am a consultant in the construction industry, and have been working away from home for most of my career. Having an aircraft would get me home more often than the typical 7 hour drive to see my young family. Growing up on a farm, running equipment, and now running computers and managing people did not lend itself to having the skill set or the time needed to produce a high quality product that I would trust the lives of my family, friends, or myself in.

Hence the search for the best people that I could trust, work with, utilizing my project management skills, and allowing me to be supervised on the parts that I could directly perform work, without mucking it up too much.

This project was conceived 6 years ago while working on a SAGD project on the Air weapons range near Cold Lake Alberta, construction began in Peirceland Saskatchewan at a private strip by Harold and myself ., and now is finally being completed in Springbank Alberta by Ralph, Bengt, Ross, and of course our test Pilot Ted.

The Blood, Sweat, Tears, and Cash that has been poured into the plane by all involved to get to this point has been substantial. I truly am thankful for all of those folks that have listened to my crazy, non conventional ideas, and in fact, shared many of them, or improved on them along the way. It has been a great experience, and it is with great appreciation that I thank all of you for the effort, and the advice, time, and laughs during this project.

And a quick note to those that said it was a waste of time and effort?..C FKRZ! It flies!

Shane Getson ? Proud Owner
 
Amazing Potential of the Turbo Subaru

Pilot Ted Sorensen completed the 3rd and fourth test flights today. We were mainly looking at powerplant data today, specifically water and oil temps, AFRs and EGTs. About -10C today and we had about half the rads and oil cooler taped off. After the first flight today logging AFRs vs. EGTs, I made some programming changes to the SDS EFI computer to richen operation above 3000 rpm. The next flight confirmed these changes were very close to the mark.

Ted was off in something less than 400 feet without trying too hard and again using only 30 inches. Running only 30 inches overhead, Ted was seeing 160-170 knots IAS at 7000 feet in some very bumpy air. This confirms the speeds Randy was seeing in his 7A STI turbo a while back were no fluke. These engines jam out some serious power and sound great to boot. Remember these engines run 60 inches from the factory and power peak is at around 6300 rpm so we are just loafing so far... All the conjecture about cooling drag and MT props don't seem to add up here as this is around 193 knots true. We are turning the prop at only 2500 and MTs seem to work well down there on other airplanes.

I got in a short test flight on my turbo Subie 6A after my annual while Ted was up. I was watching him bend the -7 around overhead while I was headed downwind. CYBW was immersed in sounds of two turbo Subies simultaneously this afternoon. Kind of a magic moment for an auto engine guy.

Shane, here are a few more photos of your baby taken with a proper camera. Sorry you could not be there to see it today. I'll try to work on another video tonight as we shot some more video today.

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Congratulations!

Hi Ralph and Ross,

looks and sounds great! glad to see we are finally getting some of these old STI's flying...

i recently got my STI running too and we have done about an hour of ground testing with SC disconnected. i get a pretty radical vibration at engine RPM's less than about 1500...she gets really smooth above 2000 engine RPM. sounds like PSRU vibration to us, however, we have no basis for comparison. i have only played with F/A ratio and have not messed with any of the stock SDS timing settings. changing prop pitch does quiet it down some.

anyone have ideas about how to lessen the low RPM growl or is this normal???

thanks for all your help throughout this LONG process! the other STI owners and Ross have helped me more than i can ever express.

best wishes,
 
Hadley said:
Hi Ralph and Ross,

looks and sounds great! glad to see we are finally getting some of these old STI's flying...

i recently got my STI running too and we have done about an hour of ground testing with SC disconnected. i get a pretty radical vibration at engine RPM's less than about 1500...she gets really smooth above 2000 engine RPM. sounds like PSRU vibration to us, however, we have no basis for comparison. i have only played with F/A ratio and have not messed with any of the stock SDS timing settings. changing prop pitch does quiet it down some.

anyone have ideas about how to lessen the low RPM growl or is this normal???

thanks for all your help throughout this LONG process! the other STI owners and Ross have helped me more than i can ever express.

best wishes,
Click to expand...

Glad to hear you are running it now.

We have a bit of rattle at low rpm which you can hear in the video on initial startup. Seems best to keep idle over 1500 to avoid the F2 TV band, this is 750 prop rpm so the airplane does not move much at this power setting. A proper TV damper would be needed to get rid of the low rpm issues.

I'm no fan of the original Eaton blower installation with the feeble and misaligned brackets and too high a drive ratio plus the questionable boost control system. The turbo is lighter, more reliable, quieter and produces more power everywhere at less boost.
 
supercharger

Ross,

thanks for the good RPM info...now i feel a little better.

remember the great debate about SC and turbos a couple of years ago, i scrapped the EATON. the original design was sloppy and poorly planned.

i redesigned the entire system for a centrifugal SC, i am using a Vortech V-5 F trim blower. my goal is about 85% of the power of the turbos without the increase in heat.

we will soon see if i made a good decision.

thanks for your continued support,

Hadley:)
 
the vortech

me too...

seems to have plenty of power with the SC disconnected anything over 4000 RPM and she wants to fly. the clear line out of the SC is just for testing and will be replaced with braided stainless.

best wishes,

Hadley
 
I've had my bird in Ralph's hangar the last couple of days, getting coaching and help from him on an annual. I saw the STI turbo fly today and met Shane, the owner. I'll admit I'm not experienced or knowledgeable in alt engines, but having ample time to peek at it sans cowling, and see it fly, I'm impressed. All the parts that are supposed to turn are turning, and those that aren't, aren't ;).

The plane sounds like an angry beast! It has a distinctive sound that is awesome.

It's gonna be cool to see what this thing can do!
 
Hadley said:
Ralph,

what kind of fuel are you using in your bird?

i am looking for a good way to boost octane without carrying too much weight especially while traveling. the STI forum is complicated and they have varying opinions of course. :confused:

http://www.iwsti.com/forums/2-5-liter-litre-factory-motor/49871-best-octane-booster.html

any idea?

super that your plane is flying.
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I think Ralph is just running Shell 92 pump gas at the moment as Subes are not that keen about lead and there's no chance of detonation with the lower CR and limited MAP. I don't see having to run over 40 inches with this setup to have amazing performance which is very doable on pump gas without additives.

This Garrett turbo is very well matched so the compressor efficiency is high. This coupled with a good intercooler setup and the ability to tailor spark timing to keep peak cylinder pressures down around torque peak rpm should make it safe. Away from home, Shane may have to use 100LL and Decalin Runup.
 
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rv6ejguy said:
......... Away from home, Shane may have to use 100LL and Decalin Roundup.
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LOL, I 'googled' Decalin Roundup, and got many 'hits' on weed killers!;) OTOH, Decalin "Runup" made more sense.

I hate when the computer keys do that to me. :rolleyes:
 
PCHunt said:
LOL, I 'googled' Decalin Roundup, and got many 'hits' on weed killers!;) OTOH, Decalin "Runup" made more sense.

I hate when the computer keys do that to me. :rolleyes:
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Ahh, thanks, made me laugh. :)You are correct of course. Late night, must have had weed killer on the mind. Brain fart not finger trouble. duhhh...

Pierre, you've tried it? I dunno, roundup all those nasty lead critters an' coral 'em then kill 'em dead. Again, thanks for the morning chuckle guys.
 
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Ralph,

It is a pleasure reading about another turbo STI flying, I hope you will keep reporting in on flight test results here and elsewhere.

I think your plans to limit MAP to around 40" is a good one. You will see plenty of performance at that level so there is really no need to push it harder than that, unless you just have to see what she can do:)

I ran mine up to 47 MAP and 4700 RPMs numerous times and was amazed at the performance. (I found the MT prop to work better at 4700 than at higher RPMs.) I was always concerned about detonation at the higher boost levels however. People kept warning me about the stock pistons not being at all tolerant of detonation. Early on in my flight testing with the supercharger on it, I would routinely see 52" MAP on take off and climb out. (I didn't know any better) It took off like a dragster at that MAP! After getting it on the ground following the (self induced) turbo failure, the engine had less than a quart of oil remaining in it and the oil looked like tar. I was sure the engine was destroyed at that point and thus the tear down and overhaul. We were so pleased and surprised to find the internals of the engine were nearly in perfect condition after all that torture I put it through. The pistons and rings were like new. The only possible indication of any damage was on one rod journal bearing. It showed some slight markings indicating possible hammering from detonation, but even that was very slight.

Power to weight ratio with a boosted STI engine is hard to beat!

The real pleasure of the turbo installation for me was the climb ability and higher altitude cruising. You will find getting it up to 15,500' happens very easily and the cruise speeds up there are well worth the effort you have gone through.

How are the turbine inlet temperatures?

Randy C
 
Randy

Still learning how to tame the beast to this point.
First flight got an EGT alarm (set at 1600F), so second flight we got EGT & AFR readings across an array of RPMs. As suspected AFRs were too lean & Ross factor'd the AFR map richer to about 12.5 for now. Results for flight 3 & 4 brought EGTs down to 1500-1550 at around 29", we may adjust ign timing later after we have a few more flights on the plane. EGT sensor is mounted approx 3" front of turbo inlet so might be reading slightly higher than if mounted at each individual exh runner.
We've been gradually blocking off airflow to the rads & oil cooler to get reasonable operating temps, & more important, more heat for the pilot! So far we got it up to 185F coolant & 175F oil. I suspect the little EGG blower/heater won't cut it for Canadian operations, so contemplating other heater solutions, hmmmm- we do have that big third rad on the firewall doing nothing...
Next few flights we will be checking out the potential overshoot/prop overreving issues and slowly adding more boost.

& yes, we are running Shell premium, I think it's 91 octane.
 
Info

Ralph,

thanks for the info... we can easily get 93 octane locally and that is what i am running, unfortunately all the auto fuel around town by law has 10% ethanol. we are working on getting pure MOGAS for the local airport without the corn.

your reminding me to get my EGT up and running...

your help and info is a blessing...keep it coming.:)
 
Update

Got about 6.5 hours on the plane now, nothing bad to report so far with the engine.

The MT electric prop is too slow to keep up with the engine when the throttle is opened with any vigor. This has been reported by others before so many leave it in manual mode at a fairly coarse angle until power is stabilized.

The weather has not been great here lately and any good weather must dovetail in with Ted's availability to get some more flying in.

We hope to get some in flight video sometime in April if winter ever ends.
 
Update

Still accumulating hours slowly on the beast. Only real snag so far has been with the original Egg fuel pumps which decided they were hungry and started to cannibalize themselves by making metal. This was found when the fuel filters were pulled around the 10 hour mark where more in depth checks were carried out on the package. Ralph is fitting replacement Walbros now.

Performance continues to amaze. This aircraft is visually faster than your average RV departing the airport and flying overhead and sounds just plain cool.
We hope to get out of the circuit (pattern) more soon to get some definitive numbers.
 
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