Van's Air Force
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RV- "Super 7"
- Thread starter BHunt
- Start date
Steve Barnes
Well Known Member
Super Six
Brad, I don't know about the 7 but the super six has never had any negative affects in over 800 hours. Many changes were made to the six, which makes it not a six any more. Beefed up wings, closer rivet spacing, Eighth inch rivets in high stress areas, heavier duty brakes, 10" longer fuselage. thicker skins, heavier engine mount, 52 gallon tanks, titanium gear legs, larger tail and more. If flown right it is very economical. 194 mph at 8.8 gph. It will go a lot faster if someone else is buying the gas.
Steve
Brad, I don't know about the 7 but the super six has never had any negative affects in over 800 hours. Many changes were made to the six, which makes it not a six any more. Beefed up wings, closer rivet spacing, Eighth inch rivets in high stress areas, heavier duty brakes, 10" longer fuselage. thicker skins, heavier engine mount, 52 gallon tanks, titanium gear legs, larger tail and more. If flown right it is very economical. 194 mph at 8.8 gph. It will go a lot faster if someone else is buying the gas.
Steve
pierre smith
Well Known Member
You kidding?
Steve built it Warren and I flew it at Chico, Ca. several years ago...rocketship!
Brad, there are several "Super -8's", super -6's and super -7's...540 cu. in. and they'll all run 200 knots or better
In the case of the Harmon rocket, you start off with an RV-4 and use all the ribs in the wings but spaced closer together, since the outer bay is cut off. Thicker skins are used on the tail feathers and often, one-piece skins on the wings as well. The IO-540's in these will also exceed 230 MPH.
Best,
How do you know all that?
Warren...............
Steve built it Warren and I flew it at Chico, Ca. several years ago...rocketship!
Brad, there are several "Super -8's", super -6's and super -7's...540 cu. in. and they'll all run 200 knots or better
In the case of the Harmon rocket, you start off with an RV-4 and use all the ribs in the wings but spaced closer together, since the outer bay is cut off. Thicker skins are used on the tail feathers and often, one-piece skins on the wings as well. The IO-540's in these will also exceed 230 MPH.
Best,
Steve Barnes
Well Known Member
Pierre, Warren The Gas Man is just trying to stimulate the thread
I've known Warren for years and if memory serves me, Warren has flown in the Barnes' Stormer. Our airports are only 15 miles apart.
Steve
I've known Warren for years and if memory serves me, Warren has flown in the Barnes' Stormer. Our airports are only 15 miles apart.
Steve
My interest was more in weight and cg. Does using an IO-540 limit you?
Or and IO-408. Do these engine options limit you elsewhere?
rvmills
Well Known Member
Brad,
I wouldn't say the larger motor limits you, but it will drive several build decisions, and it will require some careful engineering. You're asking good questions though, and weight and cg are affected, and need to be considered.
Take another look at Steve's post (pasted below), and look at what's in red (my color add). Steve's fuselage is 10" longer, mine is 8" longer, and another friend's Super 6 is 14" longer. The stretch allows placing additional weight (battery, ELT, etc) in the tail for balance (that's one benefit of the stretch...ground handling is another). The wing mods allow similar g limits at a higher gross weight, and the beefed up structure is integral to the design from the ground up to support the Rocket-range Vne.
This kind of build is perhaps more experimental, thus requires careful study and decision-making along the way. Its a hybrid RV/Rocket...or is that a Rocket/RV?
If there is a limit, it's perhaps the number of folks that you can turn to for engineering and build assistance...you'll be off the beaten path. Not sayin' that's bad...just enter the path with eyes wide open.
They're nice flyers though. I've flown an HR, an F1 and a Super Six, and all are phenomenal performers. I love the tandem Rockets for fighter-like look and fun...but to be honest, I'm kinda partial to the feel and ride in my S-6, and would happily go beak to beak with any Rocket for fun!
. Haven't flown an EVO yet though (hint, hint Mark! ).Its a fun machine...just alike all RVs! (OK, well maybe a little different)
Cheers,
Bob
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Steve Barnes
Well Known Member
Good post Bob
Long time no see. "Barnes' Stormer Steve"
Long time no see. "Barnes' Stormer Steve"
rvmills
Well Known Member
Back atcha Steve. Been buried in mods and repairing aging tid-bits. We should meet for a burger and another side-by-side run...see if any of the mods have had an effect since we flew with Pierre!
Cheers,
Bob
Steve Barnes
Well Known Member
That was an unfair race.
Remember Bob you were running with your alternate air on. When I first flew with Tom H. on a fairly calm day at 1000' msl I was seeing 258 to 261 mph on the gps. Now, as well as then, I would still put my money on the original Super Six. I think we were running over 2700 rpm's though. We should meet half way some time, maybe Auburn. Steve
Remember Bob you were running with your alternate air on. When I first flew with Tom H. on a fairly calm day at 1000' msl I was seeing 258 to 261 mph on the gps. Now, as well as then, I would still put my money on the original Super Six. I think we were running over 2700 rpm's though. We should meet half way some time, maybe Auburn. Steve
rvmills
Well Known Member
Auburn sounds good Steve...maybe we can get Mike Starkey over to show off his 10 too!
Back to our previous match up...I recall opening the ram air about halfway through the run (Mark Frederick will laugh...he's seen me repeat that "trick" [ahem] in a couple races). I remember seeing 218 KTAS at 3500' (250 MTAS-ish). When you told me you saw 260 in my plane when it was new, I was surprised, as I've never seen that level. Didn't realize it was GPS speed you were describing. I know you said fairly calm, but was that downwind? Recall the IAS? Motor age could be a factor, but compressions are still good. Doubt it still makes the 322 HP that the Lycon dyno showed in 1998 though. I've cleaned up the airframe a little, and continue to look for drag reduction opportunities. I'll race ya to AUN for that burger!
OBTW, to alleviate the delayed ram air activation problem, decided to go full time ram via Sam and Will James:
We'll have to give it a run for the (burger) money!
Oh, and the Super 7 out there is welcome to join us for the burger...and the race to it! I'd love to see your plane!!
Cheers,
Bob
Back to our previous match up...I recall opening the ram air about halfway through the run (Mark Frederick will laugh...he's seen me repeat that "trick" [ahem] in a couple races). I remember seeing 218 KTAS at 3500' (250 MTAS-ish). When you told me you saw 260 in my plane when it was new, I was surprised, as I've never seen that level. Didn't realize it was GPS speed you were describing. I know you said fairly calm, but was that downwind? Recall the IAS? Motor age could be a factor, but compressions are still good. Doubt it still makes the 322 HP that the Lycon dyno showed in 1998 though. I've cleaned up the airframe a little, and continue to look for drag reduction opportunities. I'll race ya to AUN for that burger!
OBTW, to alleviate the delayed ram air activation problem, decided to go full time ram via Sam and Will James:
We'll have to give it a run for the (burger) money!
Oh, and the Super 7 out there is welcome to join us for the burger...and the race to it! I'd love to see your plane!!
Cheers,
Bob
Mike S
Senior Curmudgeon
Sounds good to me, I hope that the 10 will be back in the air soon----this radio upgrade has turned into a lot more work than expected.
Toobuilder
Well Known Member
Was at a local fly in two weeks ago and saw a HR-2 with a stock RV-8 (-7)tail. This confuses me a bit because I thought that Van's 200 KTAS limitation on the RV-8 was due to tail flutter margin. If so, how can you hang an otherwise stock RV-8 tail on a 230 knot airplane?
Steve Barnes
Well Known Member
Where I saw that speed...
Bob, We were going west bound across the SF Bay heading back to the San Carlos Airport at 1000'. I couldn't believe the speed either. We could have been doing a slow decent, but don't remember that, and could have had a slight tail wind too, but I would guess the prevailing wind comes from the west. I will race you so you can gloat. I have done no speed mods on my plane as you have and I think you are 60# lighter too. Look forward to it. Steve
Bob, We were going west bound across the SF Bay heading back to the San Carlos Airport at 1000'. I couldn't believe the speed either. We could have been doing a slow decent, but don't remember that, and could have had a slight tail wind too, but I would guess the prevailing wind comes from the west. I will race you so you can gloat. I have done no speed mods on my plane as you have and I think you are 60# lighter too. Look forward to it. Steve
Steve Barnes
Well Known Member
The RV4 tail
Michael, the early Harmon Rockets were running the 210 mph vne RV 4 tail with no counter balance. I have heard claims that some of these planes have exceeded 300 mph in a dive. Scarry stuff, but I think most or all of them held together. In fact I believe that Bob's Super Six still has the vintage RV 6 210 mph tail on it. Steve
Michael, the early Harmon Rockets were running the 210 mph vne RV 4 tail with no counter balance. I have heard claims that some of these planes have exceeded 300 mph in a dive. Scarry stuff, but I think most or all of them held together. In fact I believe that Bob's Super Six still has the vintage RV 6 210 mph tail on it. Steve
Toobuilder
Well Known Member
I thought the HR (RV-4) tails were beefed up... Which is why I'm questioning the use of a "box stock" -8 tail on a Rocket.
So are we simply pushing these essentially stock parts to 230+ and hoping for the best?
So are we simply pushing these essentially stock parts to 230+ and hoping for the best?
longranger
Well Known Member
Per my HRII plans (ca 1997), the only "beef-up" to the -4 tail is the addition of v-shaped 0.016 doublers inside the trailing edges of the elevators and rudder just wide enough to catch the aft-most rivets in the stiffeners.
Toobuilder
Well Known Member
Interesting...
So does anyone know the source of Van's Vne limits? Has Van ever done a flutter analysis?
I'm not suggesting that Rockets are unsafe by any means, but the jump to 230 knots is a significant move. I'm curious what analysis was completed to determine there is still margin.
Certainly the real world experience of all the flying Rockets provides a level of comfort, but is there any math to back it up?
So does anyone know the source of Van's Vne limits? Has Van ever done a flutter analysis?
I'm not suggesting that Rockets are unsafe by any means, but the jump to 230 knots is a significant move. I'm curious what analysis was completed to determine there is still margin.
Certainly the real world experience of all the flying Rockets provides a level of comfort, but is there any math to back it up?
rocketbob
Well Known Member
Not math but a scary experience. A F1 had its elevators flutter with significant damage to the fuselage. Nobody really knows how fast he was going, but he was doing flutter testing and it was at a speed significantly above Vne, even on the Evo.
rvmills
Well Known Member
Excellent, will be good to see ya! Boy do I understand project creep though!
All good info Steve...thanks! And no gloating at all. You are the closest (geographically) benchmark I have to seeing if any of the work is paying off! Well paying off speed-wise anyway. Along the way I'm learning a ton...about building, re-building, maintaining...and the airplane itself. Probably the best part of all the effort (hair-pulling notwithstanding!
)When are we gonna see the Barnes-Stormer out at a race?!?!
That is correct Mike. I was encouraged to do so by SARL and AVC racing buds. Adding the counterbalance was one of the main goals. I also incorporated a couple strengthening measures after considering some mods others had done on RV-4 and Rocket Rudders and VS's. I also sought some engineering consultation. Here's what I did (not an official recommendation from me or anyone, just a couple data points...sorry, gotta say that!):
.020 skin (versus the old .016...I believe .020 is now standard. .025 was considered, but was felt to be too heavy for the rudder. As you add weight, it would require adding more weight to the counterbalance. If the added weight is significant, the stress on the counterbalance horn attachment point becomes a concern.)
Pinning the leading edge of the rudder stiffeners together, essentially making them ribs. A famously fast RV-4 did this...where I got the idea. A fellow Reno Racer did the same with his Rocket, on which he used an RV-4 tail that he modified to have a counterbalance (the fast 4 did the same thing too). The Rocket gent used tabs and RTV to pin the stiffeners together. I used .032 tabs carefully made to fit between the stiffener pairs. This added 5 ounces of weight 2 inches aft of the hingeline. I then glassed in 2 ounces of shot to the counterweight edge, 5 inches forward of the hingeline, so that it had a zero-sum effect on balance.
After adding that slight amount of weight, I added a 90 deg doubler to the hingeline connection for the counterbalance horn.
During the design and mod discussion, with a now-stiffer rudder planned, attention was shifted to the stress on the VS, and the rudder-VS attachment. I added a .050 doubler the full length of the aft VS spar, sandwiched under the standard doubler (the one with the pre-fabbed lightening holes). Careful attention was also paid to the length and alignment of the rod-end bearings for the rudder attachment as it all went together (as would be required in any install, modified or not!)
All this was to add a degree of stiffness to the rudder and the rudder/VS connection, with the addition of the absolute minimum of weight; and all were based on design features of that 260+ MPH RV-4 and the 255+ MPH Rocket.
So Michael, the questions are very valid. There has been much discussion on using TAS as the limiting speed, and that's what I do. Discussions with multiple aero engineers indicates that flutter speed appears to actually track about halfway between IAS and TAS as DA increases, so using TAS appears to be a conservative approach (and one I choose to adhere to). I'm not aware of the written documentation of Rocket Vne versus RV Vne. I know testing and evaluation has been done, and the theoretical flutter speed is much higher than published Vne, but that margin belongs to the engineer, so I respect that...in my case, the Rocket numbers as established by the original builder.
Again just one data point.
Cheers,
Bob
Steve Barnes
Well Known Member
Nose Gear Super Six?
It would be a big job to make a tricycle gear. The gear would have to be longer and the geometry would have to change too. Consider the extra weight as well.
Steve
It would be a big job to make a tricycle gear. The gear would have to be longer and the geometry would have to change too. Consider the extra weight as well.
Steve
