Super stretched -6

For those of you who don't belong to EAA or receive Sport Aviaition, there is a story about a stretched RV 6 with an IO-540 making 299 HP. The airplane also has two rearward facing seats. It's been "cleaned up" and cruises at 225 MPH!

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True experimenting!!

I'm thinking it would be quite interesting to see a -10 turned into a 6-place, there are quite a few high-output engine options that could be used for that.

Thanks for those Pics Pierre. And your right, true experimenting. I love it. Im guessing he has the tip up mod to get someone in there. Also based on my experience with the Super 7, and the fact that he did not move the front seating arrangement, that he would likely fly it with some weight back there.

In the Super 8, the pax is not a factor since I have the fwd baggage to be able to shift some weight around. But in the 7, that would be my guess.

If I remember correctly, Carl claims over 300 HP. He ran the AirVenture Cup race to Oshkosh with us last year. Very nice people.

He beat me by 10 knots last year...he better watch out this year!

He started with a flying airplane

I read the article last night. The plane is out of the Harmon Rocket camp. It is around 20 inches longer than a standard "6" so the CG has been taken into consideration in the building of the airplane. I noticed a very long center rail for the canopy so accommodation of the rear facing passenger entry and exit appears to have been considered. He bought the plane in the 4-place airframe configuration They make a big point of the effect of the landing gear and wing tip configuration on speed. The statement that the change he made to the wingtips were expected to add 7 mph to the speed but the actual result is not provided - I don't believe it for an instant. The 299 hp IO-540 with special induction and prop are big factors in the 225 kt speed I believe.

Bob Axsom

The wings on that plane have also been clipped. A special spacer is put in place to get back the missing span. Also the fuel tank goes all the way out to the wing tip. I wouldn't sit in the back of that thing if my life depended on it. The extra two seats are not really meant for adults. You might be able to talk some kids into ridding back there.

airguy said:

I'm thinking it would be quite interesting to see a -10 turned into a 6-place, there are quite a few high-output engine options that could be used for that.

Click to expand...

I think even a stretch RV-10, with an additional 12 inches with an increase in gross would be great!

I know that plane!

I happen to know a little about that plane, although I've never personally seen it. It was built by a couple of EAA Chapter 10 guys at Gundys airpark, in Owasso, OK. That was my old chapter in when I was in Tulsa. The plane was featured in Kitplane the year it was finished (sometime in the mid-90's). The pages were framed and still hang in the chapter hangar. It looked exactly the same except for the flame job. If you look close, you can tell the flames were added later.

If the name John Nys sounds familiar, it's because he was also the first guy to finish an RV10. On that day, he probably had more four place RV experience than the factory. You've got to wonder why the article didn't mention something about it.

I also don't remember anyone ever saying anything about it being based on the Harmon Rocket. They called it the "Super Six". My understanding was that it started life as a standard RV6 kit and the guys did the engineering themselves.

Anybody from Chapter 10 who was around at the time and knows the real story?

Super 6

This extra long over Horsepowered RV-6 was from what I know,,,,, was built in Oklahoma and actually flew out to my familys private landing strip many years ago (OK39) The original owner made most of the mods and yes it had a Six Banger engine in it then. The original owner later sold it and the new owner from what I know made many more changes after I met him at Okskosh 06. Here are a few pictures.

Canopy tilt......

Thanks Alan,
I noticed that the rear rails hinge upward to allow ingress/egress for the backseaters. Did you happen to look closely at the detail? Seems like the canopy hits a stop and then the rear rail is raised. Be neat to make it easier to access rear baggage on a standard slider as well. How many of you guys have the Meske (sp) system? Like it?

Regards,
Pierre

Need one more mod...

Needs to have the canopy modded so that the rear facing passengers have a rear facing machine gun.

REK

I'll chime in on this one. In my elusive quest for a four place taildragger capable of mild aerobatics (it's gotta have sticks of course) I had only identified two potential aircraft types, until I got the latest Sport Aviation. The CA-25 Winjeel is a mid 1950's warbird from Australia with a P&W junior wasp radial up front. Choice number one, but a six figure investment after importation and reassembly. Love those radials. Choice number two was, for a while, to build a CompAir CA-7 based upon the factory's advice that it was stressed to +6/-3 and capable of aerobatics. After speaking with multiple builder/owners about that I've been unable to find any that say they'd even consider flying any aerobatics in the aircraft.

I've been going through the same mental gymnastics as most of you guys since reading about the Super Six Rocket. At a gross of 2000#, the W&B allows 150# in the back with 4 hrs of fuel according to the Super Six Rocket's current owner. In the original Sport Aviation article on the RV-7, according to Van the span was increased to allow a 150# increase in gross weight over the -6, citing concerns about the number of builders choosing higher than recommended gross weights. So one could SPECULATE (I'm not sure how comfortable I am extrapolating that far) that a similarly stretched -7 might be able to cary 150# more than this stretched -6. If so, it becomes a weight and balance challenge to get 600 pounds in the cabin. God only knows how much worse the handling would be at a 2150# gross! Anyway, here's a couple of pics googled from a rivetbangers webpage that show the plane's rear seat better, just for fun:

Untrod waters....

Hi KC,
There are many instances of guys going way over gross. The best recent example was Burt Rutan's 'round the world airplane. Sure, it could be argued that he designed it for that and I'll buy that too. But the wingtips almost dragged the ground!

This is experimental aviation and it's really your call. You do the math and a 1750 pound -7 at 6 G's will bear 10,500 pounds. At 2150 pounds, you're limited to 4.88 G's, still more than almost any spam can but there may be CG issues.

Van cringes at these mods and that's understandable too. I've flown my Air Tractor at 8500 pounds and it's normal category gross is 6500. We're in the Restricted category and the airplane flies really mushy at that weight. I'm not encouraging overgross or out of CG conditions but I am supporting the case for experimental aviation....350 Chevies and Subes in airplanes...radials too. Kahuna has a beautiful Super 8 and it's his call. Jon Johannson from Oz has gone around the World three times solo in his -4 which starts the flight with 300 pounds of avgas in the back seat and 18 hours of fuel total and he's no lightweight either. No telling what he weighs on takeoff. This sort of craziness isn't for everybody and we all need to really know our limits and capabilities before we go to these distant places.

In my early days in Ag, I flew a backpack PA-18 Super Cub that has an 80 gallon hopper in the back from the factory. With 65 gallons of water/chem mix, it calculated out to 541 #'s and needed 3 1/2 turns forward on the trim crank to fly level.

Just be careful and ask the aeronautical engineers on this forum and others.

Regards,
Pierre

I don't get it ...

So the shoulder harness cable goes around which side of the rear pax necks?

Steve

My thoughts exactly, Steve. Looks like they're in just the right place to sever a neck in a bad forced landing.

Meske Mod and more...

I find a number of items in this thread that apply to my RV-9A.

1. The Meske canopy mod for baggage access is really convenient. My occasional passenger and friends comment about it as "really neat." It certainly helps when packing camping gear for Oshkosh.

2. Certifying weight and balance over Van's recommended levels: I put 2000 pounds into the equations for my RV-9A and it stayed within CG limits based on the following criteria:

a: Pilot and passenger at 250 pounds each, 100 pounds of baggage behind the seats, 36 gallons of fuel (216 pounds). I have a Hartzell constant-speed prop up front on an O-320-D1A carbureted engine.

b: The empty weight on the airplane is 1,184 pounds with minimal IFR panel, car stereo, full interior, etc.

3. I flew the airplane to OSH 2006 at max gross weight with myself (240 pounds), a pilot friend (180 pounds) and about 130 pounds of camping stuff in the cargo area. The laptop computer stayed home in 2006.

The takeoff on that trip was mushy like a Cessna 172, but the cruising speed attributes were typical at 160 MPH true air speed. The details of planning for that trip and my weight and balance issues are all covered beginning on this web page: http://www.n2prise.org/rv9a219.htm

As for experimental airplanes over recommended gross weight, the story of John Johanson and his RV-4 is on Van's web site at this link: http://www.vansaircraft.com/public/jj-plane.htm

My RV-9A at 2000 pounds is less overweight than Johanson's RV-4 at 136% approved by Van himself. That story still inspires me today, but I don't plan on being a "Earth-rounder" in my RV-9A.

Jerry K. Thorne
East Ridge, TN
RV-9A - - N2PZ
"Enterprise"

I was at L45 home of the Harmon Rocket last week and a guy was showing people the latest article. I vaguely recall seeing it before.

re: over gross-- you think Burt Rutan was able to log X country time on that trip Pierre?

John Nys

For the record, John has built 10 rv8/8a's (maybe more), built 8 or 10 rv-10s, I do not Know how many 6/7's he has built. I do know he did the super six. I think John is one of the smartest guys you will meet. He is an honest hard working guy that loves building and flying-Its his life. If John says its good, its good. He does not post or read on the internet much, he builds, and builds, and builds everyday!!. no brag, just facts!! Ed