7 vs the 6 .... question for Doug and others

[Hostage46]

Doug,

Reference your post about flying the -7 while Flash is on walkabout ... Could you offer what you see as the differences between the two ships form a flying/handling perspective?

Dan ... the ground bound nieghbor

 

[dan]

Dude, it's like Nigel said in "This is Spinal Tap." Where he wanted an amp that was just that much louder, that went to 11... The RV-7 is "one better."

 

[DeltaRomeo]

Yo Dan!

OK, the -7 I have flown (about 30 hours in it) is MUCH less pitch sensitive than my -6 in the flare and it floats more down the runway (longer wing). The roll rate is not as fast and it doesn't seem to turn in as tight a radius, but the engine/prop combo for some reason just sings like silk on this particular airframe (ECi/Hartzell). It's like driving down a new interstate road in a new Cadillac. The larger tail gives you more rudder in a crosswind. In a Xwind where I would run out of rudder correcting in my -6 (and maybe need to use a little low wheel brake or diagonal landing angle) I have something left to give in the -7.

My -6 seems to require more attention while landing...well maybe that's not worded right....it's just more 'twitchy' (which I like actually).

This help?

b,
d

PS:
Dan's referencing Spinal Tap. Man I love that movie.

Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
Marty DiBergi: Oh, I see. And most amps go up to ten?
Nigel Tufnel: Exactly.
Marty DiBergi: Does that mean it's louder? Is it any louder?
Nigel Tufnel: Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where?
Marty DiBergi: I don't know.
Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
Marty DiBergi: Put it up to eleven.
Nigel Tufnel: Eleven. Exactly. One louder.
Marty DiBergi: Why don't you just make ten louder and make ten be the top number and make that a little louder?
Nigel Tufnel: [pause] These go to eleven.

 

[gmcjetpilot]

Its all academic

If you are going to build and buy a new KIT, it is academic, RV-6's are no longer in production. The big diff is the RV7 pre-punched skins and ribs, simply wonderful. Other wise the RV7 can take bigger (heavier) engines better, CG wise, and it has higher gross and acro weights. It also carries more fuel. Other wise they are similar structurally, save the wing spar. RV6 has the strap spar cap build up, and the RV7 has a machined extrusion and a little more span. How they handle? Flown both but separated by many years. My jaw hurt as usual from grinning as usual each time I fly any RV.

 

[dan]

Dan's referencing Spinal Tap. Man I love that movie.

I was crackin up just reading it. I had to find that clip... http://www.youtube.com/watch?v=jMCquiLQ96I

Just substitute RV-6 for ten and RV-7 for eleven, and it's relevant to RVs (sort of).

 

[Hostage46]

"Well it's one louder isn't it ...."
Kids got me a copy of tap for my bday last week .... it's the best!

That's what I was looking for, flying differences, not build differences.

Cheers....

 

[petehowell]

Does that make the RV-9 2-3 better ??

Sorry, could not resist.

I know if you come in too hot, it will float at least 2-3 better - better go around........

 

[Captain Avgas]

Yo Dan!
OK, the -7 I have flown (about 30 hours in it) is MUCH less pitch sensitive than my -6 in the flare and it floats more down the runway (longer wing).

Doug, I have flown in 6s and 7s and found the head room to be better in the 7. But this could have been due to different seat thicknesses so I'm not sure.
What did you find.

 

[az_gila]

-7 tails

Yo Dan!

OK, the -7 I have flown (about 30 hours in it) is MUCH less pitch sensitive than my -6 in the flare and it floats more down the runway (longer wing).
.......
My -6 seems to require more attention while landing...well maybe that's not worded right....it's just more 'twitchy' (which I like actually).

This help?

OK.. so has anyone put the larger straight horizontal/elevator on a -6 to see if it gets less sensitive....

It would be hard to make the -6 wing bigger, but relatively easy to increase the tail area with a -7 tail.

With all of the 6's out there, I would think someone has done this change...

gil in Tucson

...the Spinal Tap dialog sounds a lot like Monty Python...

 

[petehowell]

Stein has one

Stein of Steinair has a RV-6.5 I think with a bigger tail. He will chime in.

On second thought, it might just be the vertical and rudder.....

 

[dan]

OK.. so has anyone put the larger straight horizontal/elevator on a -6 to see if it gets less sensitive....

It would be hard to make the -6 wing bigger, but relatively easy to increase the tail area with a -7 tail.

With all of the 6's out there, I would think someone has done this change...

The -6 and -7 horizontal and elevators are essentially the same (other than skin thickness on the elevator). The -7 has a longer fuselage, which has to help in the pitch stability dept.

 

[az_gila]

2 inches

The -6 and -7 horizontal and elevators are essentially the same (other than skin thickness on the elevator). The -7 has a longer fuselage, which has to help in the pitch stability dept.

thanks Dan... I got mixed up on the straight horizontal models....

But... Vans web site has the -7 as only 2 inches longer, and I thought this was in the area in front of the instrument panel.

Am I missing something here?? Is it really longer from the trailing edge of the wing to the elevator hinges?

gil in Tucson

 

[dan]

I doubt you're missing anything, but if what you're saying is true (and I assume it is), then the effect is basically like pushing the average engine/prop on any given RV-6 a full 2" forward of where it is now. That must have a CG-related stabilizing effect, right?

 

[az_gila]

Thanks...

I doubt you're missing anything, but if what you're saying is true (and I assume it is), then the effect is basically like pushing the average engine/prop on any given RV-6 a full 2" forward of where it is now. That must have a CG-related stabilizing effect, right?

Thanks Dan... that makes sense....

It's a more forward CG that stabilizes, rather than a longer moment arm to the tail.

I wonder if that was planned, or it came about as a by-product of giving more access room ahead of the instrument panel...

gil in Tucson

 

[DeltaRomeo]

If we're judging RVs by the Spinal Tap standard, then the RV-11 has to win. I mean, it goes to '11' now, doesn't it?


b,
d

 

[DeltaRomeo]

Doug, I have flown in 6s and 7s and found the head room to be better in the 7. But this could have been due to different seat thicknesses so I'm not sure.
What did you find.

Scott's -7 has thinner cushions so my head room is massive compared to my -6. I usually throw an extra cushion in to see out <g>.
b,
d

 

[JonJay]

The RV7 came after the 8 and the "6" was redesigned to take advantage of the "new" CAD technology used on the 8 and the ability to potentially share components, like spar, wing, tail, to reduce manufacturing costs and build time while taking advantage of a few aerodynamic "improvements" that came along with time.
The 6 was designed by hand, drafted by hand, and manufactured, mostly, by hand. (if you ever visited the factory in its original location)
In my opinion, the 6 is slightly more asthetically balanced and pleasing to my eye. (however, I still find it difficult to tell them apart unless they are side by side)
I have flown both and find that they are very similar with slight varients as noted in others posts.

I don't think any model is more attractive in the entire Vans line. Of course, I own a 6, so I might be a bit biased.

 

[RV7Guy]

Head room

I understand the seat pan area was lowered 2" on the 7 to provide more head room.

I'm not sure if there is any real difference in front. I think it just may be the placement of the sub panel to provide additional "behind the panel" space on the 7.

 

[dan]

Yeah, for 3-pointers, an aft CG feels better to me. But for pretty/gentle wheel landings I'll take a fwd CG any day of the week.

 

[frankh]

6a to 7a

Did my TT in a 6a but own a 7a.

Approach is quite a bit steeper normally in the 6a with full flaps than the 7a...Well the 7a can come in pretty steep but then the airspeed picks up...Did not seem to be so pronounced on the 6a...Then again the 6a had an o320 and was lighter so maybe harder to pick up speed downhill.

Overall the 7a feels more docile than the 6a, and looks like a physically smaller airplane...Maybe the main gear is taller on the 7a????

Frank

 

[Jamie]

Yes, I believe that the gear leg geometry is different on the -7A vs. the -6A. Van's lists the height of the -7A at 7 foot, 10 inches while the -6A is listed at 6 foot, 8 inches.

Look at pictures of 6As...they sit tail low whereas the -7As and -9As sit almost perfectly level.

 

[dan]

Yes, I believe that the gear leg geometry is different on the -7A vs. the -6A. Van's lists the height of the -7A at 7 foot, 10 inches while the -6A is listed at 6 foot, 8 inches.

Look at pictures of 6As...they sit tail low whereas the -7As and -9As sit almost perfectly level.

The -7A's larger rudder (especially the newer -9 style with the even larger counterweight arm) would account for some of that extra height.

And here is what I have seen in my experience weighing RVs (and having to level them!):

RV-7As tend to sit at a 2.1 degree nose-up attitude (longeron angle).

RV-6As tend to sit at a 4.1 degree nose-up attitude.

 

[Captain Avgas]

I understand the seat pan area was lowered 2" on the 7 to provide more head room.

Interesting information. I didn't think I was imagining the extra headroom. In the 6 my headsets were always threatening to hit the plexi.

 

[sprucemoose]

I understand the seat pan area was lowered 2" on the 7 to provide more head room.

I understand this too, but 1" not 2". On my 6 I raised the roll bar 3/4 inch for more headroom, and I can tell you 1" makes a significant difference.

 

[osxuser]

thanks Dan... I got mixed up on the straight horizontal models....

But... Vans web site has the -7 as only 2 inches longer, and I thought this was in the area in front of the instrument panel.

Am I missing something here?? Is it really longer from the trailing edge of the wing to the elevator hinges?

gil in Tucson

That doesn't make a whole lot of sense, the arm from the Center of lift to the engine would have to be shorter on the -7 or from the Center of lift to the HS would have to be longer to account for the ability to handle the heavier engines. Perhaps the moved the wing forward a tad on the 2" longer fuse? Anyway...