J

Jaknjoan

Well Known Member
For those owners that may want to consider an alternative to purchasing a new nose fork, and don't want to wait until availability, and/or want to save some money, here is what I did to my fork.

I had Langair Machining modify my existing fork, at a cost of $50.00, to comply with the Service Bulletin. To see some photos of the modification and re-installation on the nose of my aircraft please go to:

http://picasaweb.google.com/jaknjoan/nosegearforkmodification

Contact Langair Machining at (503)397-1478
 
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enteresting....

Jaknjoan said:
For those owners that may want to consider an alternative to purchasing a new nose fork, and don't want to wait until availability, and/or want to save some money, here is what I did to my fork.

I had Langair Machining modify my existing fork, at a cost of $50.00, to comply with the Service Bulletin. To see some photos of the modification and re-installation on the nose of my aircraft please go to:

http://picasaweb.google.com/jaknjoan/nosegearforkmodification

Contact Langair Machining at (503)397-1478
Click to expand...

How hard was it to insert the corter pin?

Kent
 
interesting idea

Does it really give you more clearance? I am having trouble picturing how. I can see that the nut ends up hidden in the fork, but doesn't it drop the fork back to the original position of the nut? Maybe I'm not seeing it correctly.
 
Cotter pin and clearance

The cotter pin goes in easy, since the front and back of the recessed hole are cut out, no problem at all.

As far as clearance, the nose leg has been cutoff 1.0 inch, and has been rethreaded, by Langair, and gives you the additional inch, which is the same as you would have if you spent $154 to get a new fork, no difference.
 
Langair cost

I think I paid $75 plus shipping to have mine modified.

Oops, this is modifying the fork. Interesting. The pics loaded really slow on dialup.
 
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Ron, you paid $75 to have the nose leg shortened and rethreaded.
I had that done to mine also, in addition to a modification of the existing nose fork (the part that surrounds the wheel).

The $50 is to modify your nose fork to allow you to use your existing fork without having to buy a new one. Van's is backordered on new forks.
 
OOOH!!

I see now. I didn't know that you had also cut off the 1 inch. Nice idea. take care and thanks for showing us.
 
Uhmmm! In looking at the 07-11-09 service bulletin, I found NO reference regarding modification of the fork. If you will recheck it, I think you'll find that the fork is to be REPLACED on ALL affected pre-Feb 2005 forks.

The principal object of the mod is to ensure greater ground clearance for the nose gear mounting nut and fork.

I don't see how you've accomplished that. If you look at figure 3 in the bulletin, you should notice that there is a vertical offset between the n/w axle and the fork/strut mount, which results in greater clearance than with the old fork.

Be safe & fly happy.
 
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the ride height is the same

but the nut is an inch or so higher. the new fork however would also raise it some. as it looks like the new fork it has a higher angle on the fork itself. he got about half of the possible height availiable.the nut us what digs in first isnt it? im going the new fork route but mak have this mod done then sell my old one. is does increase groung clearance by 1 inch as the nut is recessed in the fork itself.
 
Jake,

Great idea--makes use of what would otherwise be a valuless part (the old fork--like the one in my spare parts bin) and saves some $ to boot!!

Now, if you were to add a small skid plate of 1/8th inch aluminum attached to the front flat area of the fork and curving back and under the recessed nut/washer/cotter pin, you would have a system which would be highly unlikely to dig into the ground in the event of a gear flex. You could even use the existing grease fitting hole for the attach point. You would simply need to replace the zirk fitting when you need to apply grease. In the event of a gear leg flex on a soft field the wheel pant might crack but the skid plate should allow the fork to slide over rather than dig in. Seems to me this recessed/protected nut/washer systems would be even better than my new fork!!

Again, great idea!

Cheers,

db
 
Dimensions?

Do you have the diameter and depth of the hole? Sounds good to me, and I like the idea of adding a skid pad.

Bob Kelly
 
Hole

The diameter of the hole is just slightly larger than the diameter of the tension washers that are tighthened for breakout resistance. The hole of course is cut with a CNC mill using an end mill cutter.

A 1 1/2 inch socket to tension the nut makes the process easy. I bought a 1 1/2 inch socket for a 1/2 drive for $9.95.
 
I am wondering if you could also just cut the bottom 1" off of the old fork and accomplish the same thing?
 
Brass bushings

The brass bushings are pushed out by Langair, the recess is machined and then the brass bushings are reinserted by Langair. The standard grease fitting hole is not covered up by this process. I added two fittings directly over the contact area of the gear leg, just because, but you don't need to do that.
 
Geico266 said:
Looks like a reasonable alternative to me.

Good job!
Click to expand...

OK, after further investigation, I remain unconvinced that this is true. From Van's nose_gear_service_letter_final.pdf, he mentions that:

1. the affected forks MUST be replaced
2. they are lighter
3. they are shorter.

The last is the first thing I had noticed earlier. (At least, they appeared to be shorter to me.) This would have two very beneficial attributes.
First, the shorter moment arm would reduce the tendency of the forward portion of the strut to bend under excessive loads.
Second, having the nose wheel closer to the strut would increase the vertical moment on the strut, further reducing the aft bending moment on the strut.

Although I am not sure, it appears to me that the wheel height distance to the strut is increased over that of the old fork, which again is a good thing. Please feel free to correct me if I'm wrong.

Lastly, while I am acutely aware of limited financial circumstances, I feel that the extra $100 to purchase Van's improved fork vs modifying the old one is some of the cheapest insurance available.

Again, be safe, and fly happy.
 
I don't think that the it would matter...

Joel said:
OK, after further investigation, I remain unconvinced that this is true. From Van's nose_gear_service_letter_final.pdf, he mentions that:

1. the affected forks MUST be replaced
2. they are lighter
3. they are shorter.

The last is the first thing I had noticed earlier. (At least, they appeared to be shorter to me.) This would have two very beneficial attributes.
First, the shorter moment arm would reduce the tendency of the forward portion of the strut to bend under excessive loads.
Second, having the nose wheel closer to the strut would increase the vertical moment on the strut, further reducing the aft bending moment on the strut.

Although I am not sure, it appears to me that the wheel height distance to the strut is increased over that of the old fork, which again is a good thing. Please feel free to correct me if I'm wrong.

Lastly, while I am acutely aware of limited financial circumstances, I feel that the extra $100 to purchase Van's improved fork vs modifying the old one is some of the cheapest insurance available.

Again, be safe, and fly happy.
Click to expand...

The new fork may appear to have a different height to it, but it can't or it would change the way the plane sits on the ground. The only difference between the new fork and the cut-down fork would be the slight difference in the weight. The height of the nut above the ground will be the same as one inch of material is removed with the cut.
I assume that Langair doesn't cut the sides down because he doesn't want to disturb the weld and have to re-weld it, which could cause warping in the fork.

Kent
 
its better than it was

Joel said:
OK, after further investigation, I remain unconvinced that this is true. From Van's nose_gear_service_letter_final.pdf, he mentions that:

1. the affected forks MUST be replaced
2. they are lighter
3. they are shorter.

The last is the first thing I had noticed earlier. (At least, they appeared to be shorter to me.) This would have two very beneficial attributes.
First, the shorter moment arm would reduce the tendency of the forward portion of the strut to bend under excessive loads.
Second, having the nose wheel closer to the strut would increase the vertical moment on the strut, further reducing the aft bending moment on the strut.

Although I am not sure, it appears to me that the wheel height distance to the strut is increased over that of the old fork, which again is a good thing. Please feel free to correct me if I'm wrong.

Lastly, while I am acutely aware of limited financial circumstances, I feel that the extra $100 to purchase Van's improved fork vs modifying the old one is some of the cheapest insurance available.

Again, be safe, and fly happy.
Click to expand...

and cheaper thank buying a new fork. but its not equal.. i'll take the new fork....because ive already ordered it.
 
Backordered

FYI, on the backorder front. I ordered mine the week before Thanksgiving... Just arrived... Time to get to work doing the swap out.
 
I removed mine last night.

akarmy said:
FYI, on the backorder front. I ordered mine the week before Thanksgiving... Just arrived... Time to get to work doing the swap out.
Click to expand...

I spent 2.5 hour on the removal. Problem areas were trying to get the gear bolt to drop through the hole in the firewall. The other problem was getting the gear leg to come out the the engine mount. I finally heated up the gear leg socket with a heat gun and then was able able to get it to turn and slowly start to come out.

Oh, I also had to go searching for 1-1/2 inch wrench to remove the bottom nut.

Good luck Andy

Kent
 
Socket corrosion

Your not alone on it taking some effort to remove the nose leg. I spent more than one hour with the help of my wife. I have 600 hrs. on my 9A. It was easy going back together. I did not need to put a hole into my firewall when I built mine. Used a pneumatic wrench to back out the top bolt.
 
AMOC

The FAA would call your new approach an:

(example from one AD) Alternative Methods of Compliance (AMOCs)

(f) The Manager, Chicago Aircraft Certification (ACO) Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: ... Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

FAA sometimes issue ADs after the mgf puts out a SB. They allow others to develope other means to comply because ADs are considered mandatory and someone may have a better idea, better fit a schedule, cost less, etc as long as the same level of safety is achieved.

Since FAA is not involved, you have to take responsibility for your new approach.
 
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