chasb(at)satx.rr.com
Guest
|
 Posted: Fri Mar 28, 2008 6:39 am Post subject: Vans New front forks for RV6 and 7As |
 |
|
I took a different tack to modify the nose fork.
I had the old fork milled out an inch deep from the bottom. The lower
bronze bushing had to be removed before the milling and reinstalled
afterwards. The cut was just wide enough to accommodate the
compression washer and nut for the gear leg. A slot was cut in front
and back to accommodate installation of the cotter pin. I then cut
the leg off one inch and rethreaded. The leg now terminates inside
the old fork and provides the exact same clearance as the new fork
and cut off leg. The milling job did not touch the bottom welds
mentioned below, so the strength of the fork was not compromised.
Even better, now the nut and compression washers on the end of the
leg are recessed into the fork. I think it looks better and is safer
than Van's new fork. There was a photo of the mod on the Van's Air
Force site, but it may have been removed. I might add that Van's does
not approve of this mod, but did not state their objections.
I threaded the leg myself - BIG MISTAKE! We broke one die and chewed
up two more. At $50+ per die, it would have been cheaper to send the
leg to Langair for the mod, and the result would have been much
better and nearly as quick. There is virtually no way to rethread the
leg while the leg is on the bird - too much torque involved. One
needs a big vise and a very sturdy work table. We cut the leg on a
band saw, and that part was quick and easy.
I have a new fork for sale, if anyone is interested.
Charlie Brame
RV-6A, N11CB
San Antonio
| Quote: | Time: 02:03:00 PM PST US
From: Rquinn1(at)aol.com
Subject: Vans New front forks for RV6 and 7As
I just received my new front gear leg fork from Vans to complete the
modification recommend by Vans.
The fork did not look new, in fact it appears to have been installed
before.
I phone Vans and was told by Joe that this is the result of the
contractor's jig. Has any else noticed this?
Also I plan to make the modifications during my next annual and at
that
time
I plan to leave the gear leg in place and rethread and cut the leg as
required. Does any one have the correct thread size?
Thanks
Rollie & Rod
RV6A 799RQ
El Paso Int Airport
|
I completed my nose gear re-work this long weekend, though I went
about it
the old fashioned way re-using all my parts. Here's how it went...
The stock fork came off, stripped it of bolts and bushings, and I
hacksawed
off 1" from the bottom. This took about 1 hour of sawing by hand. I
*highly*
recommend a powered saw by all means. A die grinder then sliced the
bottom
wedges (moving aft) toward the axle. The rough cut is now done.
Then came a bunch of grinding & filing & polishing to get everything
parallel and airworthy. I stopped when the top and bottom bushing
faces were
within 0.005". The major fork work is now done.
With the weld on the bottom removed, I needed to get some strength
back. I
was not interested in re-welding and heat-treating the fork, so I
chose to
add a 5/16" dia. x 5/8" long allen head "set screw" as a shear pin.
This is
placed just aft of the fork pivot, and 3/8" above the cut, in the
meaty hunk
of aluminum fork. Drill & tap, then set with locktite.
I also added a couple 3/4" lightening holes near the axle, just like
the new
fork. This was followed by a deburr and cleanup, with a shot of paint to
finish. Pound the bushings back in, replace the bolts and grease
zerk, and
it is ready to install. Note: the stock zerk location *just* clears the
bushing when re-installed, so it did not require any modification.
Now the really hard part...threading the gear leg. We did it on the
plane. I
used an adjustable 1.25 x 16TPH die with 18" extension handles on
both sides
of the die holder. It took 2 guys wrestling the die for about an hour
to cut
the threads. The gear leg gets so hot you can almost burn yourself! Used
lots of oil and backed off 1/8 turn after every 1/2 turn cutting. It
took 3
passes while necking the die down to get the nut to easily spin on. (The
next day I was a sore puppy!) This die was able to get 2 gear legs
cut and
is now missing many teeth...pretty much trashed. I have the 2.5" die
holder
(w/die) for $25 shipped if you want to buy it and try it. New die is
about
$40.
Last step is to die grind off the bottom 1" of the gear leg, clean up
with a
grinder, redrill the cotter pin holes, and put it all back in place.
Same
mounting for the wheel pants...so no changes there. Went for a test
hop and
my first comment is...no more nose wheel shimmy at ~18 knots...that's
nice!
Hope it stays that way.
Maybe 8 hours of work (some of which is very hard). If I did it
again...I
would send the leg to the shop for cutting of the threads. The $100
saved
was a pain of hard labor and I'm not 21 any more like my helper.
Doing it in
a vise would be a little better, but not much! The other work was just
another day of building airplanes, which is much like fishing, only more
productive and always satisfying.
If you want an old fork - send me an email and I'll sell it for $50
shipped.
It is minus one bushing that was used for a shim.
Happy New Year and Blue Skies!
__________________
Kelly Patterson
kbob at cox dot net
190 hours
RV-6A N716K
PHX,AZ
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
