RV-4 horizontal stabilizer attachment

hcccs · #1 01-08-2011, 03:33 PM

When I built my RV-4 fuselage I bolted on the HS:s attachment bracket. Now, when I tried to mount the HS I had to remove the bracket, rivet it to the HS and then bolt the HS back on. The thing is that I cannot get my hand down inside the fuselage to hold the nuts while I undo the bracket bolts. I'd like to use a wrench which would make it even harder. I could remove the elevator push rod but it still seems impossible. If it can't be done maybe I could drill and ream five of the nine rivet holes and bolt the bracket to the HS.
How is it done?

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131RB · #2 01-08-2011, 05:28 PM

Hans,
I dont have the plans in front of me but if memory serves me right thats the 410 bulkhead that the angle is over (it doesent matter). The question is if the bolt and nuts are on the front side of the bulkhead or the aft. Once again if memory serves me right they are aft. If they are aft you should be able to reach through the lightning hole on the cover to get to them as long as the vertical stab isnt mounted. If they are forward of the bulkhead unless your are really determined you will have to find a bud to climb back in the tunnel and install them and hold a wrench for you.

Jaknjoan · #3 01-08-2011, 05:36 PM

[quote=hcccs;501958]When I built my RV-4 fuselage I bolted on the HS:s attachment bracket. Now, when I tried to mount the HS I had to remove the bracket, rivet it to the HS and then bolt the HS back on. The thing is that I cannot get my hand down inside the fuselage to hold the nuts while I undo the bracket bolts. I'd like to use a wrench which would make it even harder. I could remove the elevator push rod but it still seems impossible. If it can't be done maybe I could drill and ream five of the nine rivet holes and bolt the bracket to the HS.
How is it done?

Hans,

I'm quite familiar with the -4 and the building process, having finished a -4 in 1988. That a/c was sold in 2003. I now own another -4 that I assisted in building in the early 1990s, that I purchased from a friends estate in 2008 after he died. Just one year ago I removed the empennage and turtledeck then changed it to a fastback, using parts from the Harmon Rocket. Of course I had to install a modified Harmon Rocket canopy also.

Your photo leaves me a little confused. It seems that you may have gotten a little ahead of yourself. It also appears the turtledeck skin extends past bulkhead 410, when the turtledeck skin normally ends pretty well flush with the flange of the 410 bulkhead.

I would drop the elevator push rod, if that is interfering with your access. You could also change all the rivet holes, enlarge them to a #12 holes and use #10 bolts in place of rivets, if the attachment of the bolts is possible as far as access to nuts.

You better hurry and finish that airplane because they are great aircraft and you don't want to miss the enjoyment for much longer.

Lots of luck. If you have any specific questions you can also PM too.

Jake Thiessen
Independence, OR

WAM120RV · #4 01-09-2011, 09:09 AM

Hi Like Jake says you have not got things in the right place, and have got things a bit out of order........ none of these things are terminal, you have just made life difficult for yourself, but we all do that on occasions.

Ok, getting the bolts in and out is difficult, almost impossible with the push rod there......so first thing I would do is remove the pushrod. Then the bolts can be accessed. The inboard ones are relatively easy you can get your hand in with a flexible coupling on asocket to undo these nuts. The outboard are a bit more difficult and you may not be able to get a socket on these due to them being close to the angles.

I use an open ended spanner to hold the nut and undo the bolt, not the preferred method of undoing a nut as it can take the plating off the bolt, but needs must.

Then when you have that angle off you can rivet it to the HS spar as per plans.

You will find that when you are setting up your fairing and drilling holes for the attachment points it needs to come off a few times. The fairing vans supplies was **** so I had to make a new one. There are some good threads on this.

Tom Martin · #5 01-09-2011, 09:31 AM

It is possible, not easy but possible, to get your arm through the forward hole and bend your hand backwards to put those washers and nuts in place. You can glue a washer to the nut with super glue, BE CAREFUL, and put a tiny bit of super glue on your finger. Knowing that you will loose that bit of skin will encourage you to use a small amount! This job can then be done without removing the push rod, I have done this more then once without using glue. If your hands and arms do not fit find a teenager to help you.
Of course you can always remove the push rod and bell crank and send someone back in the fuse. This might even be faster then trying to glue yourself to the airplane and risk spraining your wrist!

hcccs · #6 01-10-2011, 01:23 PM

131RB,
The bracket is facing forward as from -93 when the attachment point for the HS was strengthend, I guess, because they added a bracket to the underside as well.

Jaknjoan,
I can see that I did not read the plans carefully enough. I have now trimmed of the excess turtle deck skin as per plans. I decided to drill and ream the rivet holes and use bolts instead and that works fine.
I got my first ride in an RV this August (RV-6) and that boosted my enthusiasm for the project.

WAM120RV,
I could reach through the upper lightening hole without a problem. I agree with you on the fairing - I couldn't use it so I made my own (I saw a picture on the forum) and it is screwed only to the HS and not in the front. We'll see if I'll be needing a fastener in the front end.
Tom Martin,

I used your technique and glued the washers to the nuts. Worked well!

Thanks all for your input.

Hans

Derek · #7 05-06-2012, 04:47 PM

I'm about to install aft deck F-419, I have split bulkheads F-410 and F-410A

My bulkhead F-410 sticks up above the longeron by approximately 3/4" and the builders notes say F-419 is to be installed against F-410 with the forward flange facing down.

However, I have a newer set of builders notes that say F-419 to be installed against F-410A with the forward flange facing up.

Im guessing there were plan revisions for this part of the construction, is there a preferred way to install F-419 ?

vfrazier · #8 05-07-2012, 11:08 AM

Super glue? Ouch! Tom is obviously much tougher than me. I use a blob of grease, just big enough to keep the nut/washer together, and another small blob on my finger. Keeps my hands baby-butt soft too.

On my second RV-4 (a Rocket actually) I installed nut plates during construction to avoid the arm contortions.

If you look around, you can find nutplates that have a real nut captured in the housing, not just the typical one-piece nutplates that are common in the kits. I doubt that it makes any real difference. I had them available so I used them.

acroboy · #9 05-27-2012, 09:27 PM

Derek,

Have you found an answer to your question? I got to the same point today. My plans and drawings show F-419 flange up against F-410A but my F-410B sticks up above the longeron by 3/4. I'm guessing 410B is trimmed flush to the longeron but it would be nice to hear from someone who's been there already.

Quote:

Originally Posted by Derek

I'm about to install aft deck F-419, I have split bulkheads F-410 and F-410A

My bulkhead F-410 sticks up above the longeron by approximately 3/4" and the builders notes say F-419 is to be installed against F-410 with the forward flange facing down.

However, I have a newer set of builders notes that say F-419 to be installed against F-410A with the forward flange facing up.

Im guessing there were plan revisions for this part of the construction, is there a preferred way to install F-419 ?

Derek · #10 05-28-2012, 04:09 PM

Hi,

I trimmed 3/4" from the top of bulkhead 410 this then allowed the forward upturned edge of F419 to be riveted against F410A. The picture Ive attached shows how it looked after being removed using a dremel cut off wheel, I tidied the edge up later using a file. ( looks much prettier now)

http://img267.imageshack.us/img267/9749/rv4022.jpg

Also,

When it comes time to rivet F419 in place, I'm curious as to how the support piece of 3/4 x 3/4 angle is attached to the forward face of F411. This is the piece of angle that goes under F419 in front of F411.