I had an idea on how to mod an off the shelf car shock
and convert it to an air spring.
Drill a hole and drain the oil. Tig weld or braze a pipe
fitting on. refill with oil and plumb to an air pressure
can.
Paul Lamar
You can buy shocks that way now. Takes the fun out of when the shock
will blow up when the oil vapourizes from the heat.
Dale Davies
Got any specific car model suggestions Dale.
Preferably something heavy like a sport ute or pickup truck.
Got any junk ones lying around I can play with and test.
I'll pay shipping. I need mono tubes.
Paul Lamar
What you want is "remote reservoir shocks" for off road apps. I give the
site
for Bilstein only. Search off road shocks and other manufacturers
will be listed.
<http://www.4wheelparts.com/parts/bilstein/shocks.aspx>
Off road should give the weight capacity you are looking for and you
should be
able to vary the air or gas charge in the reservoir for tuning.
Dale Davies
The Wheeler board has some info regarding failure of the nose gear from
lateral loads. Specifically, they warn against
parking until the nose wheel is straight. With this info, I have decided
to use 2 shock/spring units in a V shape
instead of one vertical member like the pics in this thread are showing.
This will help support the system laterally
approximately 18 inches from the mounting point helping with side loads,
and allow the use of 2 smaller units instead of
one larger shock.
Kevin Alderman
Everybody has trouble with nose gears including Van. It is because most
pilots land crabbed in a cross wind.
Paul Lamar
I found out what does not work. Cost me $25 :)
I was hoping to luck out.
A Gabriel ProGuard #61565 Hecho en Mexico for a Chevy Taho is a two tube
shock and useless for our purposes. Here is a picture of all the
parts.
Paul Lamar
Paul, i'll cover the $25 cost of R&D on the shocks,
Alex
Forgetaboutit :) Lunch money :)
Looks like Edelbrock from Summit has the cheapest remote
res shocks at $90.
If you want to pay for one of those I will try to shorten
it.
Paul Lamar
I got the strut Alex.
The gas pressure was about 25 psi giving us a force
of 80 pounds. The piston area is about 3 square inches,
So I expect we might be able to go to 100 psi
giving us about 300 pounds force from the strut.
We will still need a die spring or two.
We might find some rubber donuts that might be lighter.
We wont have to modify it. It can be used as is. I was worried
it was too long but it is only 15 inches long collapsed.
I'll do a scale 3D shortly.
Paul Lamar
Hi Paul, looks promising. With this system i see the nose strut reacts the loads straight into the air frame top
mount
point, how beefy must this firewall hard point be to carry the 6G design load as the nose strut loads are not going
through the engine anymore.
With Kevin's idea of 2 shocks he halves the loads having it between 2 mounting points, say between the 2 top
mounts, but
more weight then obviously,
Alex
It is always a good idea to bond the SS fire wall sheet metal directly to
the fiber glass and plywood part of the firewall. This adds tremendous
strength and stiffness to the entire fire wall. I designed a round a round
dirt track race car for a company that manufactured them years ago. Thin
steel sheet on both sides of the plywood made the firewall literally bullet
proof.
I will upload pictures of the combined top MM and nose gear hard point shortly that we used on a Kiss cruiser.
BTW the weight of the shock is 7.5 pounds. You might get 3 pounds out of it by shortening it but I would not do that
until it was complexity proven.
------------------------------__------------------------------
It was a bit difficult assembling it so I will change a dimension or
two to make it easier to assemble. You just need to add some carbon layers in the top center of the firewall to the
top part of the fuse below the windshield. A half inch straight 4130 steel tube just inside the windshield to the
fire wall would add a bit of bird strike and roll over protection and add strength to that entire area. The weight
would be near nothing.
Paul Lamar
Hi Paul, I think i will glass down 8 or 12 layers on either side of some
solidstock when I get back and it should make the firewall to fuselage
intersection strong, pretty similar to how they do it for the other corner
engine mount points, the tube inside the windshield might be problematic as
I would need to bend it at the fuselage to window join and when taking it to
the ceiling there's very little overhead space after I get in, but that area
is already strengthened with the reinforcing for the door cutouts. There
have been 2 recorded rollovers and it held up and wasn't an issue,
Alex
Use half the layers with a carbon fiber :)
I had in mind a straight tube but it is not essential.
How thick is the wind shield material? A lot of kits are too thin for bird strike IMHO.
Paul Lamar
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