A

ao.frog

Well Known Member
Hi.

I'm about to start cutting for an access panel on the fwd deck, but before I do any cutting, I want the hear if anyone has some comments og suggestions?

Instead of making two small panels in the middle of the fwd deck, I thought that one bigger might do the trick?
I plan to install nutplates on the middle rib so the accesspanel can be screwed onto that one as well as along it's four sides.

I might also make two additional access panels on the lower sides of the fwd deck, but I'll decide that after making the middle one.

Thoughts people?


 
Most I have seen have used two smaller access panels. You have your cut line going through the center of the rivets in the center support angle. I am not sure of what your thoughts are there. A single large panel would be pretty nice though. What are your thoughts for attaching the panel to the center support rib?

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Van does not recommend any inspection panels in this skin as it is a structural skin. Do so at your own risk.
 
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Mel said:
Van's does not recommend any inspection panels in this skin as it is a structural skin.
Click to expand...
Just curious, as I have been debating whether to put these in my plane for many months now, and its nearly Go-Time for me on this one. What is the source of your information, Mel? Do you have an email or other reference you can post which documents Vans' position on this? Normally I would take your very experienced word on this, but the reason I ask is that post #15 of this thread http://www.vansairforce.com/community/showthread.php?p=343669
conflicts with this statement (note that I raised the same point in post 11).

I would like to see some documentation on this either way so I (and I'm sure AoFrog) can move forward with a decision.

Thanks.
 
Maybe Ken knows better. I was going with the recommendation from Van himself several years ago.
 
Mel said:
Maybe Ken knows better. I was going with the recommendation from Van himself several years ago.
Click to expand...

And being a long time sheet metal box builder as I am (HVAC business), I'm not a fan of putting access holes in this very important structural skin either. Same goes for messing with the corrugated bulkhead behind the baggage compartment. When you remove a side or end from a box structure, D structure or tube, it's amazing how the structure becomes very unsupported.
I guess it all depends on how many screws and nutplates will do the job.

L.Adamson --- RV6A
 
I would very careful installing acess panels. Skin everywhere is structural on a semi-monocoque airframe. That said a properely placed and installed access panel can be structually neutral, neither strenghtening nor weakening the airframe. The internal doubler ring should be 1 gauge thicker than the original skin. Standard rivet spacing similar to surrounding structure. My orignial plan was for no access panels. However after climbing underneath once I realized its worth the effort to install them.
 
That's not big. This is big.

rv7-11172009198.jpg

Nothing really set in stone yet. Gonna have an a couple airframe guys look at it when the time comes. Worse case I have to buy a new skin, best case I can finish my airplane sooner.
 
Cfrisella said:
rv7-11172009198.jpg

Nothing really set in stone yet. Gonna have an a couple airframe guys look at it when the time comes. Worse case I have to buy a new skin, best case I can finish my airplane sooner.
Click to expand...


Is that carbon fiber? That looks pretty cool.
 
Fab it myself although not prepreg. It's made with epoxy and cured it an autoclave. Painting isn't a problem really. The skirts and windscreen have already been filled and sprayed with a urathane matt clear. I like the look so most of it will remain carbon.
 
Awesome, yeah technically easy to paint, but to cover up the carbon look is dreadful. Very nice custom look! I bet you could make some $$$ producing those. I can't imagine there is any structural concerns there. What type fasteners do plan? Titanium would be a nice look. Stainless is also an option.
 
If your goal is behind the panel access

have you considered a tip down panel? I can post some pics if you're interested, but on my 7A I have good access to all the wiring behind the panel while sitting in my seat. :D

Early Mooneys had access panels like you're looking at. I recall problems with leaks, but good comments on access.
 
A.O. If you plan your panel right, you don't really need access panels with a tilt up like you have.
 
Be careful, corrosion can come

The carbon (or the aluminum) should be covered with glas fiber or paint, so that no direct contact between carbon and bare aluminum is. Otherwise it is likely that corrosion come up and eat away the aluminum.

I do not find anymore the source of this, maybe somone else can help.

Regards, Dominik
 
Alf,

Couple things I see as potential issues would be how the backing plate will cross over the center rib. If you cut it, it may weaken the structure. If not cut, it will raise the skin over the rib plus you'll need to build up the rib to match. the other is that because this skin is pulled pretty tight, you may have an issue where the large panel is not strong enough to keep from concaving (is that even a word?).

I had two access holes, one on each side of the center rib in my -7 and loved them. The GRT AHRS was under one and all the wiring to my avionics stack and Lightspeeds plus other important stuff was under the other.
 
screws/nuts?

Is your windshield fairing nut/bolted to the windshield? I assume you laid up on the window and finished off-plane before installing? Looks nice.
 
The windshield is screwed/nuts to the frame. The the frame will be screwed to the forward deck with nut plates. When I get to finish the forward skin I'll build it up flush to the frame. I just had a difficult time seeing the windshield and frame glassed down.
 
INSP. PANEL

RV-6, N16DD, IO-360. INSTALLED A PANEL THAT COVERS THE TOP THREE RIBS WITH 1.5" SPACING. I KNOW A LOT OF SCREWS. THE ACCESS HAS BEEN VERY USEFUL.WE FLY IF HARD NO PROBLEMS. WRENCH
 
I'm just not a fan of cutting these access holes in what amounts to being an aircraft section that should stay as rigid & supporting as possible. After all, there is 350 to 400 lbs of weight hanging out there, and a lot of gyroscopic forces to go with it. This section is somewhat of a structural backbone to the forward fuse.

I'd prefer to build a panel that's in three removable sections & mounted to a skeleton frame. That's what I did. In the meantime, to access underneath, I just pull out the right side joystick, and place a few pillows underneath & over the seating area. At 6'1", it's actually quite comfy down there, and I could even go to sleep. Just have good lighting an I-pod and cell phone. :)
I have two handles welded to the roll bar to easily pull myself out.

Since the first flight, I've redone the radio stack by installing two different radios, as well as a audio panel. Pre-wired it all at home, and took the setup to the airport. Wasn't all that tough, since it was all wired including new headphone jacks.

At least I don't have to worry about any rain water, or paint chips when removing screws and panels.

L.Adamson --- RV6A
 
Tomahawk Side Access NACA Vent

The pictures below are of a Piper Tomahawk with the NACA scoop built into a nice rectangular access panel right behind the instrument panel. I thought that was a neat idea, but I'm not brave enough to cut up my side skins.

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thanks

Hi again.

Thanks for the input folks. (and sorry that some did hijack attemps... )

My initial thought with the line going through the two rivetholes, was that a screw in these two holes would hold both the panel and the skin level to eachother.
The more I look at them, the less I like them, so I have decided to move the cutting line for the panel to the middle beetween two rivetholes.

Thanks also for the tip about making the panel and it's parts stronger than the surrounding skin. That's what I'll do too.

Before I make any final decitions and cutting, I'll take one last time to think all this through.
As part of it, I've made a poll regarding the access panels in a separate tread. It's nice to get a percentage reply too...

The poll is here: http://www.vansairforce.com/community/showthread.php?t=54769
 
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Answer from Vans.

Hi again.

I asked Gus at Vans what he thought about my plans for the access-panel, and here's his answer: (he has given me permission to post it here)
Therefore, I think I'll move the cutting line to the middle of two rivets, make the reinforcement stronger than the surrounding skin and go ahead and make that panel.


On Tue, 23 Feb 2010 10:17:53 -0800
> "Gus Funnell" wrote:
> > We don't recommend cutting access panels in the top
> >skin, as it is a
> > structural part. That said, it has been done without
> >apparent problems
> > provided sufficient reinforcement around the holes is
> >used. It's maybe not so
> > useful on a tip up as a slider where the access is
> >worse. If you do one large
> >panel like you show, it would be good to tie the
> >reinforcing ring to the center
> > rib. I think you'd have to use some sealant on it to
> >prevent leaks.
> >
> > Gus
 
Fwd Panel Cutouts

I put in 2 cutouts and consider them invaluable. The backup rings are a bit thicker than the panel itself, so with that and corner radii the same as the wing access panels (I don't remember dimensions off hand), that area is actually structurally stronger than the original panel. I did a form-in-place seal with proseal and strips of fishing line to assure a min thicknkess of the sealant.
 
done deal....

Hi again.

We're done with the access panel now, except for the proseal-fitting and here's the result:






The nutplates are for #6 screws.
The ring underneath is made from .40 material. The panel itself is made from .32 material.

I don't think we'll make additional access-panel on the sides, as it probably will be possible to some degree to work "sideways" from the center.
Besides, we're planning to wire and connect the different stuff underneath the panel for easier access.
 
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