What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

HS Attach Hardware Access

J

Joe

Well Known Member
RV-8A, QB fuse, empennage test-fitted ...

As I was looking at how narrow the RV-8/8A tail becomes as it tapers aft, I wondered how others have installed the four AN3-10A bolts that attach the forward part of the horizontal stabilizer to the fuselage after the aft top skin has been riveted.

Specifically, how do you access the nuts and washers on the underside of those bolts (DWG 78)? They're just forward of the F-8108B-1 Bulkhead Assembly and easy to access with no aft top skin but I don't see myself reaching through numerous lightening holes to install the nuts.


RearBulkhead.jpg
RearBulkhead.jpg
RearBulkhead.jpg


Do others crawl into the tail cone, install nutplates, build an access panel in the fuse side, invert the bolts, use double-sided tape on fingertips and a lot of cursing, or what?

Thanks,
Joe
 
Joe,

You just have to squeeze in there to install (AND torque) the nuts per the plans. To avoid having to do it more than once, just install a couple wing-nut clecos to hold the stab in place during construction. Inverting the bolts will do little good, as you still have to hold the head of the bolt while you torque the nut. Be sure to use new, never torqued bolts when the final assembly is being performed. Do not install nutplates. Remember, the forward attach point for the horizontal stab is also the forward attach area for the vertical stab. Good luck.
 
Those pesky nuts and bolts....

Ah yes, a vividly remembered morning of torture! We tried crawling donw teh back of the plane to access from the inside but there was too little space/we were too large.

We were finally able to get the nuts and washers onto the bolts by reaching in through and round the various access holes with the nut and washer assembled in a suitable wrench and held in place with some insulating tape.

Description of the process is as follows:
- put the tape over the wrench socket, sticky side up. Push the nut into place - the tape will stretch out and the nut will be a very tight fit into the socket so it won't drop out. Now put the washer in place over the nut. The tape around the edge of the nut will hold the washer in place.
Reach in and finagle the nut and washer into place on the end of the desired bolt, gently turning the bolt by the head to get the nut threaded. Once its on just tighten it all up. From memory we managed to torque thru the access holes too, just about enough room to do it.

I hope that's a clear enough explanation

We had spent an hour trying to get the first nut in place using just fingers when our ever-helpful inspector wandered by and heard the language. He suggested this technique and it took us only a few minutes to get it completed.

It took some days from hands wrists and forearms to recover from this episode. If anyone has another, better, way of doing this job I would love to hear about it.

Chris
 
fehdxl said:
Why is this?

Thx,

Jim
Click to expand...

Jim,

When a bolt is torqued, it stretches and induces strain on the threads. Overtorque can cause the bolt and/or nut to fail. It would be nearly impossible to tell if a "hand-tightened" bolt that was previously installed was inadvertently overtorqued. Re-using a hand-tightened or torqued bolt could result in failure.

Some may have other theories or experience, or claim it's unnecessary (and I'm sure others have discussed this issue on this board); but when it comes to a super-critical area like flying surface or control surface installation, I would use nothing but new bolts and nuts. Besides, they're cheap....it only costs a few bucks to make sure they're brand new.
 
Access Panel

Along the lines of Joe's question, I've just drilled fuselage skins and am looking for other things to prepare for before taking it all apart again.

I am also considering the difficulty of access to the horizontal stabilizer bolts, the static air connections, and the possibility of mounting the ADAHRS unit in the rear fuselage. Things that are difficult to access are not likely to be looked at as often as they should be

Would there be any structural issues with installing an access panel about halfway between the front of the stab and the static vents. I am thinking of something 4 to 5 inches square, rounded corners, reinforcing ring etc? Our Mooney has 5 access panels in the rear fuselage...

Any thoughts??

Regards

Ron

r0clfr.jpg
[/IMG]
 
inspection plate

I know of one rv in my hometown that has an inspection plate, 4" round i think, in that area. No problems and it helps too on condition inspections. I am not sure yet if I will put one or not. I will look closely at this when I get my fuse. to that stage though.

bird
 
Inspection Plate

Ron Townson and I talked about this approach last weekend when he was here for Van's Homecoming. I'm beginning to like it a lot and will probably go this way (inspection plate) after hearing about the alternatives (Jeff Atkinson. and Chris, above) and with the "prior art" reported by Bird.

Once I overcome my reluctance to cut a hole in the skin, fabricating the cover and flange will be the easy part.

Thank you all -- great to have it come together and make a decision.
 
HS Attachment using nutplates

During several of my sessions of lurking, I have come across a couple of builders that have opted to use nutplates to attach their HS. I thought that this was a great idea considering how difficult it is to install the attachment bolts, nuts and washers. Also, with everything I do on the aircraft, I try to consider the issue of future serviceability. I finally decided to install some nutplates for my HS attachment based primarily upon the experiences and postings on the excellent site Mickey's RV8. http://www.rv8.ch/index.php?page=19
Here he shows his installation and confirms that Van's found no problem with the use of nutplates in this application.

I hope this will be as helpful for you.
 
You must log in or register to reply here.
Back
Top