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RV-7 Rudder.... Does size really matter?

Rudder it out!

  • Build it sleek and sexy the way the almighty Vans intended!

    Votes: 9 60.0%
  • Go big or go home! Think about all the extra aluminum you?ll have down the road!

    Votes: 6 40.0%
  • Build both and sell me one!

    Votes: 0 0.0%

  • Total voters
    15

Ryano

Active Member
Recently picked up a protozoic and orphaned RV-7 Empennage kit #70101 off eBay.

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Subtract out the prototype RV-7 and yes, as confirmed by Vans, I?m the proud owner of the 100th RV-7 kit!

Not sure yet if I?ve gotten myself in over my head, but I?m going to make a go of it. I kind of have to at this point.

#100 has already spent over decade forlorn in a basement! (No fault to the original builder?.. They have valid reasons.)

The packing list shows that this kit was shipped with the pre-SB 02-6-1 RV-7/8 rudder.


I?ve searched the forms for all the info available and it looks like the two driving factors for going with, or not going with, the RV-7/9 rudder upgrade are?

1)Better spin recovery as noted in the SB 02-6-1.

2)Negative effects of the larger 7/9 rudder on W&B/C.G..


The big questions at hand are??.

1) Is it worth it to acquire and build the larger rudder?

2)Does Vans still honor the complementary rudder upgrade as noted in SB 02-6-1?

Ready...Set?Go!
 
Is it worth it to acquire and build the larger rudder?

The parts won't be that expensive .. it's usually shipping that gets you with large aluminum sheets .. considering it was an SB I would go with the updated assembly.

Edit: Oh, and CONGRATS on your find!
 
I'm already planning on ordering everything I need to also complete SB 14-01-31, so adding extras is in the plan. Likely one or two extra trim tabs as that seems to be an often reworked item.
 
7 rudder

I would opt for a 8 rudder . The overlap seam is in the front eliminating the double flush rivets on the trailing edge . A few 7's have had tail issues not any 8's that I know of .
 
I would opt for a 8 rudder . The overlap seam is in the front eliminating the double flush rivets on the trailing edge . A few 7's have had tail issues not any 8's that I know of .

A few pilots grossly exceeded VNE. They happen to have been in 7's. Thus far, there is no evidence of any problem with the 7's rudder.
 
Ryan,

A few things...

1) I would vote in the poll but the first response says, "The way Van intended". The only thing is, Van wants you to build and install the newer "9" rudder.

So much so, in fact that there is no charge for you to get the parts from Van if you have an early kit like us!

I have kit #70312.

Get the parts and build either one or both.

2) Either rudder works fine. I still have the "9" (riveted trailing edge) parts new in box and never bothered to build it. I built and installed my "8" (folded trailing edge) rudder and it worked just fine for the past 700 hours. I do mild acro and it is all need. I haven't done any accelerated spins though. Maybe I will build the "9" rudder someday???

3) Also... Be advised... The elevator counterweights on our kits are also different. They weigh slightly more (maybe ounces?) but it's still negligible.

Nice number and enjoy the build!!!

I will let you know if I am ever in your town and take you for a ride in my 7. I get around pretty good in the summer months!

:) CJ
 
Ryan,

A few things...

<snip>

3) Also... Be advised... The elevator counterweights on our kits are also different. They weigh slightly more (maybe ounces?) but it's still negligible.

Nice number and enjoy the build!!!

I will let you know if I am ever in your town and take you for a ride in my 7. I get around pretty good in the summer months!

:) CJ

I have 70173 and would recommend the updated counterweights on the elevator. It is a real improvement in use of the mass for counterweight. It is just a couple of parts per side. Get an updated drawing (order the thumb drive with all drawings and OP drawings) and it will have the part numbers.
 
I have 70173 and would recommend the updated counterweights on the elevator. It is a real improvement in use of the mass for counterweight. It is just a couple of parts per side. Get an updated drawing (order the thumb drive with all drawings and OP drawings) and it will have the part numbers.

Also the HS-00001 spar doubler X 1
HS-00005 X 2 ribs
HS-00006 X 2 ribs
will give you the current updated parts for the spar SB. All shown on the newer plans
 
1) I would vote in the poll but the first response says, "The way Van intended". The only thing is, Van wants you to build and install the newer "9" rudder.

I only put that as an option as reading through the SB I came away with the impression that Vans take was "Meh.... improves spin recovery a 1/4 of a turn faster. Do whatever you want.".
 
Get an updated drawing (order the thumb drive with all drawings and OP drawings) and it will have the part numbers.

I have the more modern preview plans and the kit included the OG preview and full size plans to cross reference from.
 
Congrats on the new project

I have both a 9 and 8 rudder for my 7A. The 9 rudder has more power, but felt heavy in comparison to the light aileron and elevator forces so I tried the 8 version. The 8 feels lighter, more in tune with the other controls. The 8 rudder takes a little bit longer to initiate or recover from a spin, not as long as a basic trainer, just not as instantaneous as the 9 rudder. Lastly, the 9 rudder provides better yaw stability while cruising in turbulent air. With the 8 rudder, I do a light dance on the pedals during turbulence to improve passenger comfort, the 9 rudder only requires even pressure on both pedals to stiffen the tail. Both rudders work well for crosswind landings.

My plane has light nose due to fixed pitch composite prop, lightweight starter and alternator. I am saving up for a CS prop, and once I add that weight to the nose and HP to the takeoff roll, I think the 9 rudder will work better

Cheers,
Jay
 
Agree

I tend to agree that there isn't any known evidence with the zipper trailing edge rudder. However, data does indicate the folded edge rudder tends to stay with the AC more often than the zippered trailing edge rudder. Once its unzipped, well, its over.
Stay within design limits, and it should be ok.

Seems like the choice is either going with the zipper for a slightly faster spin recovery or go with the folded for more margin. Zipper head or folded head. :)

Good luck with your new project and hope you have lots of fun!

cj


A few pilots grossly exceeded VNE. They happen to have been in 7's. Thus far, there is no evidence of any problem with the 7's rudder.
 
Congrats on the new project

I have both a 9 and 8 rudder for my 7A. The 9 rudder has more power, but felt heavy in comparison to the light aileron and elevator forces so I tried the 8 version. The 8 feels lighter, more in tune with the other controls. The 8 rudder takes a little bit longer to initiate or recover from a spin, not as long as a basic trainer, just not as instantaneous as the 9 rudder. Lastly, the 9 rudder provides better yaw stability while cruising in turbulent air. With the 8 rudder, I do a light dance on the pedals during turbulence to improve passenger comfort, the 9 rudder only requires even pressure on both pedals to stiffen the tail. Both rudders work well for crosswind landings.

My plane has light nose due to fixed pitch composite prop, lightweight starter and alternator. I am saving up for a CS prop, and once I add that weight to the nose and HP to the takeoff roll, I think the 9 rudder will work better

Cheers,
Jay

Thank you! This was exactly the insight I was looking for.
 
RV-9 Rudder

If you go with the RV-9 Rudder make your F-792 Rudder Stops as per my drawing below. I originally made my stops as per the Van's drawing but had to redesign them to achieve the correct rudder maximum deflection.

Remember to leave an additional 1/16" material on the contact face as you can trim it later to achieve the correct deflection, but you can't put it back on.

https://www.flickr.com/photos/141779426@N07/25775267443

https://www.flickr.com/photos/141779426@N07/26105124980

Welcome to the RV family and enjoy the building process.
 
If you go with the RV-9 Rudder make your F-792 Rudder Stops as per my drawing below. I originally made my stops as per the Van's drawing but had to redesign them to achieve the correct rudder maximum deflection.

Remember to leave an additional 1/16" material on the contact face as you can trim it later to achieve the correct deflection, but you can't put it back on.

https://www.flickr.com/photos/141779426@N07/25775267443

https://www.flickr.com/photos/141779426@N07/26105124980

Welcome to the RV family and enjoy the building process.

Thanks for the info.... I'm likely going to buildup a internal rudder stop, so I'm wondering if there is also a difference there as well.
 
Thank you all for the great information! After giving it some thought, I'm going to build both rudders and keep them all for #100.

At a minimum I'll have some awesome wall art.

Plan is to build the -7/8 rudder I have on hand now and get around to -9 when/if I have a dead spot and time to kill in my build.

Next set of questions are.....

1) Is the SB'd -9 rudder replacement a complete standalone build kit, or does it scavenge parts from the -7/8 rudder kit? If "Yes" what do I need to order to make the two complete rudders of -7/8 and -9 variety?

2)What issues might I face switching out rudders during, and/or after, phase 1 testing? I would assume at a minimum a separate W&B would be needed for each configuration, but could I log/POH it as such that a "Hot Swap" would be a nonevent in the eyes of the FSDO?

(yes I'm aware that swapping a rudder is not an easy thing...)
 
I will let you know if I am ever in your town and take you for a ride in my 7. I get around pretty good in the summer months!

:) CJ

Please do! I show you the local sights and supply a place to stay if you don't mind sleeping under a uncompleted wing!
 
Swapping rudders should not be trouble after you have the experience. The rudder stop (external) might be the most trouble as the aft two rivets will be close to the VS spar. The 9/7 rudder kit is almost complete but will need counterweight, and pivot helm/lock nut. They can be removed from the original but I just purchased extra for easier comparison. Be sure you get the VS tip, rudder tip and lower fairing with the kit as well. A call to Vans will confirm.

Oh - just weight them and determine CG (hang from a string from two different points) to log the W&B difference.

Now go get that thing built!!
 
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