Hello. On my RV7-A (I am not the builder), the AN5-20A nose gear leg attachment bolt is installed from the top (the nut is on the bottom) of the engine mount. This is backwards to what Vans dwg 46A shows. Because of this (I think), the bolt is too close the firewall and interferes with the plug that is used to plug the hole in the firewall when the bolt installed per the drawing. I am thinking if I remove the bolt and install it the way the dwg shows - I will be able to install the plug and not have a hole in my firewall. Is my thinking correct? What torque setting do I use on the bolt, will it come out easily, (guessing I need to jack up the nose before pulling the bolt), and any other hints/ideas much appreciated. Thank you so much for your help!!!
Van's Air Force
Don't miss anything! Register now for full access to the definitive RV support community.
7A Nose Gear Leg Attachment Bolt Direction Question
- Thread starter tthrew
- Start date
Jesse
Well Known Member
You could leave it for now and use something else to plug the hole. The main reason the bolt is installed from the bottom, as I understand it, is to allow you to torque the nut with a torque wrench, which you can't get on the nut as installed in your plane. Ideally, bolts should be installed from the top down whenever possible so a nut falling off won't cause the bolt to fall out of the hole.
The main reason(s) is that it puts the bolt in an orientation that allows for driving it out if the gear leg needs to be removed, and there often isn't enough space for a standard nut and washer.
The standard for bolt orientation is "unless otherwise specified by the manufacturer". In this case we could substitute designer for manufacturer.
A bolt torque chart is in Section 5 of the construction manual. If you don't have a manual, you should get one if you are going to be maintaining the airplane yourself. A copy of the manual is available on CD for $10 from Van's
Last edited:
Raymo
Well Known Member
I wanted to install the bolt from top down and looked for options to do so but ended up installing it per plans, which includes a hole in the firewall to drive it out when the time comes.
I made a simple cover from stainless steel to cover the hole. One round plate on the front side with a stainless steel screw through to another round plate on the inside. High temp sealant between the two.
I made a simple cover from stainless steel to cover the hole. One round plate on the front side with a stainless steel screw through to another round plate on the inside. High temp sealant between the two.
This is how I have done it.
On my 6A, I just replaced the bolt with the next size longer. Added a washer under the head to allow the full shank of the bolt to be in full contact with the hole drilled in the mount.
Removing the bolt was no problem.... Vise grips and a small hammer. Installing the bolt was no problem... just place the washers and nut as the bolt starts to extend out the hole. The firewall can be flexed in this area to allow clearance from the end of the bolt.
Torquing was easy from the top. Add the bolt drag to the torque spec. No hole in the firewall.
Removing the bolt was no problem.... Vise grips and a small hammer. Installing the bolt was no problem... just place the washers and nut as the bolt starts to extend out the hole. The firewall can be flexed in this area to allow clearance from the end of the bolt.
Torquing was easy from the top. Add the bolt drag to the torque spec. No hole in the firewall.
mikehoover
Well Known Member
This is what I ended up with. The standard bolt was a bit loose, so I used a close tolerance bolt. I had to cut an elongated hole in the firewall because I had previously located the first hole about 3/8" too low. I riveted the cover plate to cover the hole. I like the idea of a plate, sealant and screws FWF with plate nuts [spell check won't leave me alone with plate nuts as one word] mounted to the aft side of the firewall. I think you could maintenance that bolt from the fore side without having to get under the panel.
I don't understand how adding a washer under the bolt head allows for full contact of the bolt shank with the hole drilled in the mount.... ???
Anyway, glad your bolt came out easy when you needed it too. They often times don't. In those cases people are usually happy the bolt is installed head down.
rightrudder
Well Known Member
A good general rule. One place I deviated was the bolts attaching the rudder cable clevises to the rudder horn, so it's easier to inspect the condition/security of the cotter pins on the pre-flight.
