What's new
Van's Air Force

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

RV-7 Horizontal Stabilizer Assembly Video Part#1

I posted a reply on the video, but here I'll put it here just in case:

I am not sure I would have used washers on the bolt head side. I didn't when I bolted my HS-411 down to my rear spar. The plans manual details how many threads you need to have on the tail of the bolt after the nut has been torqued, and I am not sure there there will be enough threads on the tail using a washer on both sides.

5.20 in the plans manual states that you need at least 3 full threads past the nut after the proper torque has been applied. This is under the "MS Nuts" paragraph, but I am sure it applies to AN3* nuts as well.
 
These videos are spectacular! It's one thing to read about it but to see it is way more useful. Thanks for the effort!
 
I posted a reply on the video, but here I'll put it here just in case:

I am not sure I would have used washers on the bolt head side. I didn't when I bolted my HS-411 down to my rear spar. The plans manual details how many threads you need to have on the tail of the bolt after the nut has been torqued, and I am not sure there there will be enough threads on the tail using a washer on both sides.

5.20 in the plans manual states that you need at least 3 full threads past the nut after the proper torque has been applied. This is under the "MS Nuts" paragraph, but I am sure it applies to AN3* nuts as well.

Completely agree. However, If I go to a longer bolt and maintain the 3 threads would it not be better to have a washer on both sides?
 
Completely agree. However, If I go to a longer bolt and maintain the 3 threads would it not be better to have a washer on both sides?

I don't see any harm in doing that other than the few ounces it would add back there. Just remember being all the way back there a few ounces can make a difference with that much arm when it comes to weight and balance.
 
Yea these videos are great--This one has reminded me to re-cleco my HS to check and make sure that tapered flange is not too close to the inboard aft rib. I did not check that during assembly. Will be doing that before I prime everything this weekend.
 
If I recall, the bolts have a washer-shaped flat on the underside of the head. So they are designed to bear on just that surface. Structurally, they're fine without a washer as the plate they are bearing on is steel and acts as its own washer against the aluminum. Adding a washer would distribute the load slightly as the washer would be larger than the integral flat.

There is no harm in adding a washer, other than the added weight of the washers and the necessary increased length and therefore weight of the bolts... Every additional unnecessary gram comes out of your useful load at the end of the day.
 
5.20 in the plans manual states that you need at least 3 full threads past the nut after the proper torque has been applied. This is under the "MS Nuts" paragraph, but I am sure it applies to AN3* nuts as well.

No, it doesn't apply to AN365 nuts. For AN365 it is Maximum 3, but at least 1 thread. The 365 nuts are taller.

You would only need a washer under the bolt head if you were forced to torque the bolt rather than the nut. Not so in this case, you have good access to the nut. So if it isn't specified on the plans it isn't required. If you do this throughout the build you'll spend a lot on longer bolts and add much unnecessary weight.
 
Thanks for all the great advice!

Thanks to all who have been replying to these threads!

I will leave the washers out as per the knowledge out there.

I believe i might have made a major error. If you watch me setting rivets on the forward spar i just realized i am installing the rivets in backwards if the shop end is to be against the thinner material.

Is this a show stopper?
 
I believe i might have made a major error. If you watch me setting rivets on the forward spar i just realized i am installing the rivets in backwards if the shop end is to be against the thinner material.

Is this a show stopper?

No I think you're fine. AFAIK this is more of a guideline than a rule. The Rviator from 2004 has a short article on this. 27 years of Rviator should be required reading imo!

It's handy to know what the reasons are behind such a guideline. If you do install a rivet with the shop head against a thin sheet you will see localised buckling of the sheet under the pressure of setting the rivet. This can look like a sheet separation issue but is actually not. It is less noticeable in the middle of a sheet and very noticeable on a narrow flange. If you can't reach the rivet shank with a feeler gauge then the issue is purely cosmetic.

There will be instances where this will be unavoidable such as when a flush rivet is specified. This happens on the wing rear spar in a couple of places.

I've also heard it mentioned that the shop head should be on the outside of a closed structure. George Orndorff mentions this in his wing video, although he is not sure of the reason other than it "looks nicer". I personally think it may be a future maintenance and repair issue. It's very difficult to cleanly remove a rivet if you can't access the factory head. Take a look at the recent aileron SB. Those who followed the "rule" and installed the brackets with the factory head against the thinner spar web will have a hard time removing the brackets if they need to.

Hopefully someone more experienced than I can confirm my opinions, but of course the final say is up to you!
 
This makes sense!

No I think you're fine. AFAIK this is more of a guideline than a rule.

George Orndorff mentions this in his wing video, although he is not sure of the reason other than it "looks nicer". I personally think it may be a future maintenance and repair issue. It's very difficult to cleanly remove a rivet if you can't access the factory head. Take a look at the recent aileron SB. Those who followed the "rule" and installed the brackets with the factory head against the thinner spar web will have a hard time removing the brackets if they need to.

I have asked about this twice here already. But I hadn't thought of that. I was also thinking that it looks nicer. Just didn't want any inspector telling me later to drill them all out because they are the wrong way around...Great stuff!
 
?

Thanks to all who have been replying to these threads!

I will leave the washers out as per the knowledge out there.

I believe i might have made a major error. If you watch me setting rivets on the forward spar i just realized i am installing the rivets in backwards if the shop end is to be against the thinner material.

Is this a show stopper?

I'm very new at airplane construction and riveting, but I thought the recommended method was for the factory head on the thinner material.

What did I misunderstand?
 
From what I have gathered that is the recommendation, to put the manufactured head on the thinner material.

However, its also noted that this sometimes can't be done, and its acceptable to put the shop head on the thinner material. From what I have read the clamping force difference is negligible either way, but you just have to be careful when setting the shop head on the thinner material so that the expansion doesn't cause the material to pillow/balloon out.

It seems like one of those things where if you can do it and set the rivet fine, then the preference is to put the manufactured head on the thinner stuff. But, if its going to cause you issue with trying to set the rivet, go ahead and ignore the rule.
 
Oh thank the Lord!

These rivets don't wanna come out nice drilled to #40 perfectly with 3/32 punch a beating. I'm machining an alu backer to really support the shop end while I'm forcing the rivet out. Basically a bucking bar with a hole drilled to match a #40 dimple for supporting the sub structure while removal. The three pieces are making the rivet "ribbed for her pleasure" if ya know what I mean.
 
Side cutters

Look at page 5-04 in chapter 5 of preview plans. Get some side cutters and grind the side of it down flush...you can then use them to grab the shop head, a little twist, and she pops out real easy (this is after drilling out the manufactured head obviously). Works like a champ!
 
Back
Top