Another nose wheel S B Question

[Rick_Luck]

Forgive me for what might be a trivial question, but I have a curious mind?

When I removed the nose gear leg yesterday, I removed the only bolt/nut that holds it in and thought how awkard, to have a plug in the firewall that must be removed to get the bolt out. Then last evening I was thinking, "Why didn't they simply insert the bolt from the top and place the nut on the bottom, eliminating the need for the removable plug in the firewall?" I thought that maybe there was some interference above the bolt, preventing this but when I looked this morning - and it would be easy.

I'm relatively new to aircraft mechanics, but in the little time I've been working with it, I've also been made aware of a "tennant" that if possible - all bolts and nuts should be installed so if the nut were to somehow come off, gravity should hold the bolt it. I guess the removable plug in the firewall "captures" the gear leg strut bolt. Is that the reason the bolt is inserted from the bottom and not the top?

Like I said, kind of trivial but also interesting in explaining the awkard set-up with the removable firewall plug.

Thanks

Rick Luck
RV9A

 

[az_gila]

It changed...

A change happened somewhere along the RV way.

The original RV-6A plans show the bolt inserted from the top and no hole in the firewall.

gil A

 

[DGlaeser]

Too close for comfort

<snip>
"Why didn't they simply insert the bolt from the top and place the nut on the bottom, eliminating the need for the removable plug in the firewall?"

I had that same thought, and the answer came when I saw how close the gear leg tube is to the firewall. Now I have a 'non standard' engine mount for my Egg-Subaru, but I think that area is a duplicate of a Vans mount, because IIRC, my son's airplane (with a Van's mount) has the same issue. The threaded part of the bolt sticks out far enough that it interferes with the firewall. Even if you were to create a little 'bump' in the firewall to clear the bolt, I believe wrench access is still a big issue (at least on my mount).
It is quite apparent that the tri-gear was not part of the original design, but added later. Just wait until you install your main wing bolts - and have to tighten those nuts

 

[Rick6a]

.....When I removed the nose gear leg yesterday, I removed the only bolt/nut that holds it in and thought how awkard, to have a plug in the firewall that must be removed to get the bolt out.....

Rick,

A few days ago, I replaced the nose gear leg after being reworked to comply with the recent S.B. To do so only required reinstalling the 5/16" bolt from the top down. Originally, when I built the airplane I did have to shave a few of the bolt threads at an angle parallel to the firewall. This was done to assure positive clearance...no rubbing allowed. Thread protrusion with the nut installed and the bolt clocked just so is more than adequate. As I reinstalled the leg I thought to myself..."What a PITA this would be had I installed that firewall plug in the first place and then had to remove the interior, get under the instrument panel and reach over or thru the rudder pedals just to get after that bolt."

 

[kevinh]

"What a PITA this would be had I installed that firewall plug in the first place and then had to remove the interior, get under the instrument panel and reach over or thru the rudder pedals just to get after that bolt."

I'm totally with you on this, and wish I had not even bothered with installing that firewall plug - after looking at your photo.

That said...

It wasn't that bad doing this mod. I didn't need to remove the interior or even go inside the plane.

While removing: I attached a little bit of tape to the bolt to ensure it didn't drop down through the hole.

While installing: I wrapped a little bit of safety wire around the head of the (new) bolt and made a nice little nest for it to sit in and pulled on that safety wire until I could get the bolt through to the nut.

Took about 10 mins off and 15 mins on.

 

[rvbuilder2002]

Rick,

I]"What a PITA this would be had I installed that firewall plug in the first place and then had to remove the interior, get under the instrument panel and reach over or thru the rudder pedals just to get after that bolt." [/I]

Say you've flying your RV for a few years and a need arises to remove the nose gear leg and that darn bolt is slightly rusted and you cant get it to budge. You will think it is a lot more of a pain to remove the engine mount from the firewall so that you can tap the bolt out from the bottom (it has happened). My rebuilt RV-6A has the RV-7/9 style floor cover...take me about 5 minutes to remove it. I don't see what the big deal is.

BTW...it doesn't require reaching over or through the rudder peddles, the hole is about two inches above the floor dead center on the firewall.

 

[Rick6a]

What If....

A change happened somewhere along the RV way.
The original RV-6A plans show the bolt inserted from the top and no hole in the firewall.gil A

Say you've flying your RV for a few years and a need arises to remove the nose gear leg and that darn bolt is slightly rusted and you cant get it to budge.......BTW...it doesn't require reaching over or through the rudder peddles, the hole is about two inches above the floor dead center on the firewall.

I hear you Scott, BUT.....My RV was flying for a few years and the need to remove the nose gear leg did arise. Even if the bolt was slightly rusted, (it was not) access to the bolt head with a socket and ratchet handle is easily achieved and in the event the bolt was seized it is likely that the bolt could have been broken loose via aggressive leveraging with a ratchet. Certainly, as you mentioned in your post there is always a potential worst case scenario but as they say....you pays your dues and you takes your chances. As Gil pointed out...the plans did originally call for the bolt to be inserted from the top.

I do stand corrected about the rudder pedal situation though. Still a minor nuisance to deal with, they are not a major player. Because the hole is about two inches above the floor dead center on the firewall, I would have had to disconnect and remove the battery (its box located per vintage plans) to get to it.

 

[AlexPeterson]

Say you've flying your RV for a few years and a need arises to remove the nose gear leg and that darn bolt is slightly rusted and you cant get it to budge. You will think it is a lot more of a pain to remove the engine mount from the firewall so that you can tap the bolt out from the bottom (it has happened). My rebuilt RV-6A has the RV-7/9 style floor cover...take me about 5 minutes to remove it. I don't see what the big deal is.

BTW...it doesn't require reaching over or through the rudder peddles, the hole is about two inches above the floor dead center on the firewall.

Scott has a good point. I wanted to remove my gear leg after a few hundred hours for inspection. Rust was not the problem, but the bolt (which was a standard diameter AN) had worked in the socket enough where removing it was really, really a long process. I had the bolt head up as per the plans of that vintage, and had to work the bolt rotationally while finding things to pry up on it. I recall spending around 3 hours or so getting that dang bolt out. I replaced it with a close tolerance bolt and haven't had issues since, including the most recent removal at 950 hours.

Doing it again, I'd probably put the hole in, but plan on not using it regularly (keep the bolt head up). The bolt has to only be put in part way, the nut started, then turned down.