What's new
Van's Air Force

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

RV 8 Landing gear NUTS!

Robercom

I'm New Here
During inspection of my RV 8 landing gear I noticed one of the outer brackets was bent. I grounded the plane and ordered both the outer and inner brackets. The inner bracket was a challenge but the outer bracket is proving to be impossible. After a lot of headache and some verbal language I would never use around women or children I was successful in getting the bracket off. I got the new bracket in place and got both bolts through. Here is the issue... I was finally able to get the nut finger tight on the on the forward bolt. However, after 6 hours, bruised left forearm, bruised ribs from leaning over the side of the cockpit I finally gave up trying to get the back nut on.

I tried just using my hand and holding the nut with two fingers, I tried using painter's tape on the nut so I could put it in a socket and have it stay there while I tried to start it. I tried praying, pleading and offering my soul as sacrifice with no luck.

Looking for any advice from anyone who has changed these brackets after the build with wires, brake lines and fuel lines in the way. Frustrated...
 
Welcome to VAF

Brian, welcome to VAF:D

Pretty sure someone will come along with some help soon.

Good to have you aboard.
 
There are two AN3 bolts that may interfere with the nuts. They are shown in the cropped picture below. You have to loosen the AN3 nut so the bolt will retract to allow you the clearance to insert the nut from inside the gear tower. At least I think this is the problems from your description.

I also find it helpful to use Gorilla tape to secure the box wrench to the bolt head underneath the gear towers as I torque the nuts inside the tower. The tape will hold the box end to the nut to prevent the wrench from falling out. The long arm of the wrench will wedge against the landing gear structure to keep it from moving as torque is applied. I am not looking forward to retorque the nuts when I get my airplane flying. I also hope you are replacing the stock nut with the upgraded NAS nut as described somewhere in the RV8 forum

P.S. I find the open thread length of the original AN3 bolts is a bit long the long side which interferes with the access to the landing gear tower nut. I replaced one AN3 bolt with a slightly shorter one, still keeping 1 thread showing, to prevent the access problems you are experiencing
 

Attachments

  • Capture.JPG
    Capture.JPG
    220.5 KB · Views: 520
Last edited:
I'm using the Vans stock brackets.

I believe I will try to back the bolt out and hold the nut over the hole while a helper gets it started from below. Anyway that's my next oh please make this work idea.

Is there any reason the torque cannot be achieved with the torque wrench on the bolt side while the nut is held in place? Would seem to me that would serve the same purpose and would be easier. I just made myself laugh considering the word easier in this situation. I should have said less than almost impossible.
 
I'm using the Vans stock brackets.SNIP

Is there any reason the torque cannot be achieved with the torque wrench on the bolt side while the nut is held in place? Would seem to me that would serve the same purpose and would be easier. I just made myself laugh considering the word easier in this situation. I should have said less than almost impossible.

You can do this, if you take into account the running torque of just the bolt. For example if it takes 10 ft-lb to turn the bolt with no nut (or nut loose), add this to your final torque setting. Here the old school beam and pointer torque wrenches come in handy - but I assume you can do the same with a clicker torque wrench.

Carl
 
There has been lots of discussion and conversation about this.

First, PLEASE install the NAS1804 nuts, not NAS679 nuts. The NAS679 stamp-formed nuts are not sufficient for this application. Many examples of these being found loose. Our tests prove that they don't get loose by turning - they get loose by the nut expanding radially enough under tension that the threads actually leapfrog over to the next thread!
The primary reason for installing the better nuts is strength, but an added benefit is that they have smaller wrenching size, so easier to get a socket on the nut. Since the nuts are taller, it is desirable to buy bolts with longer threads - these are NAS6606 rather than NAS6206. The grip length stays the same. Although I say this is desirable, I don't believe it is strictly necessary. If you insist on have clear threads protrude beyond then nut, then yes, get the NAS6606. But with the NAS6206, there is sufficient thread engagement into the locking area of the nut, but perhaps not enough to protrude beyond the nut. So if you are a stickler for that, you will want the NAS6606.

Second, please read the installation instructions for the U-803 bracket. The faces that mate to the bottom of the fuselage are to be filed/ground down so that those faces do not touch when proper torque is applied. If I recall correctly, the prescribed gap is 0.030" or so - but the thing that matters is that they don't touch. This is done to assure that the bracket applies sufficient clamping pressure on the gear leg. If the faces of the bracket were to contact the fuselage prior to reaching proper torque, then adding more bolt torque does not clamp the bracket any tighter onto the gear leg. Unfortunately, this design does mean that the bracket does bend slightly at the proper torque. In a perfect world, it would be better if the faces did touch just at the proper torque, because this would prevent the bracket from bending, but in practice, you have no way to assure that the correct clamping pressure is applied to the gear leg if those faces touch.

Third, it is sort of OK to torque the bolt head rather than the nut, given the near impossibility of torquing the nuts unless the gear tower modification is done. But torquing the bolt head adds a lot of friction from turning the bolt in its hole, so one technique is to measure the friction torque with a torque wrench before drawing the bolt tight. This accounts for the bolt friction, and the locknut friction. Then add this to the specified torque value to get the torque needed to get proper value on the bolt. Even this is conservative, because as the bolt tightens, the friction increases AND the U-803 bracket bends slightly and tends to add more friction from binding on the bolt.

Many RV-8 builders were/are wise to do the gear tower modification to make working in this area quite a bit easier. In hindsight, I do so wish I had done it.
But the good news is that with the good NAS1804 nuts, you will not ever find that they have loosened. I have found that I can check the torque each year by putting a torque wrench on the bolt heads, and the nuts don't turn at the proper torque - I don't need to have a wrench on them.

Hope this helps. If you would like to learn more about this assembly, use the search capability. Look in particular for a very long thread called "breaking news" where we tested various nuts. Any additional questions, feel free to PM me.
 
After a lot of headache and some verbal language I would never use around women or children.

Need to be careful in your wording, that could be classified as a sexist remark. Lol
 
Lots of good info.. Based on the other threads I just ordered the NAS6606-27 bolts and the NAS1804-6 nuts.

Next task will be to hire a small kid with long skinny arms and really strong hands.
 
Bruce Brielmaier is a VAF member who makes a clip to lock the bolt head in place in the gear tower so that the bolts can be installed from the top and one person can check the torque from the bottom at each annual condition inspection as recommended in the construction documents. I had to replace the bolts, nuts, and saddles last year before learning about these clips, but now have a set and plan to install them this year. We found if we jack up one wing, we could get enough play in the gear leg to make installation of the saddles, bolts and nuts a bit easier. Still, a long-armed, skinny helper would be useful.

Search for “Bloody annual - done” thread for a discussion about the clips.
 
I have installed 3 of Bruce’s bolt clips on RV8’s. It takes way less time to install these than trying to do what you are doing, and on your subsequent condition inspections, it takes just a couple of minutes to check the torque on those now easily accessed nuts doing it solo. Get the stronger nuts, but install the bolts from the top down using Bruce’s bolt head clips.
I’ve installed all three of them with the airplane standing on the gear - airplane chocked.
Remove one of the bolts on one side (fore or aft), reverse the bolt with the bolt head retention clip on it, inserted from the top. I used a brass rivet set on my rivet gun, set at a very low pressure to thump the bolt home, making sure the clip aligns with the bolt flats and the gear tower channel. Install and torque the nut and washer (high strength), torque to the spec’ed torque.
Then do the same on the other bolt on that side, and repeat.
 
Last edited:
Hi Scott. Any chance of a picture of the inside and out side of your gear setup with these new-fangled bolts, please?
 
I'm using the Vans stock brackets.



Is there any reason the torque cannot be achieved with the torque wrench on the bolt side while the nut is held in place? Would seem to me that would serve the same purpose and would be easier. I just made myself laugh considering the word easier in this situation. I should have said less than almost impossible.

Why not reverse the bolt so threads are down and lock the bolt heads in place? Then torque the nuts from below where access is easy.
 
Last edited:
I have installed 3 of Bruce’s bolt clips on RV8’s. It takes way less time to install these than trying to do what you are doing, and on your subsequent condition inspections, it takes just a couple of minutes to check the torque on those now easily accessed nuts doing it solo. Get the stronger nuts, but install the bolts from the top down using Bruce’s bolt head clips.
I’ve installed all three of them with the airplane standing on the gear - airplane chocked.
Remove one of the bolts on one side (fore or aft), reverse the bolt with the bolt head retention clip on it, inserted from the top. I used a brass rivet set on my rivet gun, set at a very low pressure to thump the bolt home, making sure the clip aligns with the bolt flats and the gear tower channel. Install and torque the nut and washer (high strength), torque to the spec’ed torque.
Then do the same on the other bolt on that side, and repeat.

I would love a set of those clips.. which Bruce made them, and how do I get them? Actually 3 sets would be ideal, as it would make my life easier while I maintain 2 other -8s
 
During inspection of my RV 8 landing gear I noticed one of the outer brackets was bent. I grounded the plane and ordered both the outer and inner brackets. The inner bracket was a challenge but the outer bracket is proving to be impossible. After a lot of headache and some verbal language I would never use around women or children I was successful in getting the bracket off. I got the new bracket in place and got both bolts through. Here is the issue... I was finally able to get the nut finger tight on the on the forward bolt. However, after 6 hours, bruised left forearm, bruised ribs from leaning over the side of the cockpit I finally gave up trying to get the back nut on.

I tried just using my hand and holding the nut with two fingers, I tried using painter's tape on the nut so I could put it in a socket and have it stay there while I tried to start it. I tried praying, pleading and offering my soul as sacrifice with no luck.

Looking for any advice from anyone who has changed these brackets after the build with wires, brake lines and fuel lines in the way. Frustrated...

Brian
Do you have a photo of the bent U brackets?

Thanks
Sam
 
Would you mind getting him to contact me too,please? Just been sitting here searching for him on this forum.

I, too, am after a set of these bolt clips for an RV8 build.

I am in Australia, so would need to arrange freight with him.

Cheers,

Ben
 
To All,

I have Retainer Clips available. You can use PayPal or check to order.
PM me or email via this site.

Cheers.

Bruce Brielmaier
 
Just realized I had an old email address entered here. It's updated, if you sent a reply try again or PM.

Thanks.
 
Just realized I had an old email address entered here. It's updated, if you sent a reply try again or PM.

Thanks.

Bruce, I would love some of these clips.. I can’t seem to reach you.. I tried PM, email, and here. If you are interested in selling a set or 3, please let me know. Thank you!
 
RV8 main gear

From recent experience I have learned that the main gear mounting system on the 8 is poorly designed, certainly not up to the standard expected of Vans. In the first place the outboard bolt is inserted from the bottom upwards. This would not be so bad EXCEPT that it then does not use a full high tensile nut, but a thin pressed nut which is not meant for tensile use, but rather for shear.

The truth of this can be seen from the numerous experiences here of nut threads being stripped, jumping threads or being found loose. To compound the problem, it is very difficult to check the torque on the nut due to its position.
After a near catastrophic failure of the nut, we have modified my aircraft to allow the bolt to be inserted from the top, with the high tensile, full sized nut easily accessible.

We all like our RVs and in general are impressed by them, but the gear design on the RV 8 tail dragger is poor as many have noted here.

Anyone interested in further details feel free To contact me privately.

Regards to all, Brent
 
Back
Top