View Single Post
  #1  
Old August 15th 15, 06:39 AM posted to rec.aviation.soaring
Steve Thompson[_2_]
external usenet poster
 
Posts: 21
Default Changing Cobra compression brake gas strut

For the hitch, technique suggested by Cobra:-

http://www.cobratrailer.com/wp-
content/uploads/Kupplungstausch_englisch.pdf

At 04:10 15 August 2015,
wrote:


In my older Cobra trailer, that's normal behavior. The

damper just
prevents=
the tongue from slamming the brakes full on in a

hard stop. It also
preven=
ts the tongue from hitting the stop in fully expanded

position in hard
acce=
leration. It is, in fact, very much a shock absorber,

not a spring.=20

That's not to say that later models don't have gas

springs; I wouldn't
know=
.. But I would think it would make more sense to use

a coil spring with
prog=
ressively higher force the more the tongue is

compressed rather than a gas
=
spring with its nearly linear force/deflection profile.

But I'm not an
expe=
rt.=20

If you can deflect the strut by hand by slowly

compressing it, and if it's
=
about as difficult to expand as to compress, it's a

damper. You'll know if
=
it's a spring: lots of force in one direction and if you

let it go, it
expa=
nds quickly to its free length.=20

The nice thing about the damper, at least in my

trailer, is that you just
u=
nbolt the tongue, including one end of the damper,

and slide out the
moving=
, inner (piston) tube. Bolt in the new damper on one

end, then insert the
t=
ongue and slowly compress it by hand while peering

into the hole in the
ton=
gue for the other end of the damper. When it finally

comes into view,
inser=
t a punch to line everything up, then insert the bolt.

It's literally a
5-1=
0 min. operation after you've done it once.=20

The older Eberle trailers didn't have anything, as I

recall. In a hard
stop=
, the trailer brakes would come on suddenly causing

the trailer wheels to
b=
riefly lock up, especially on uneven pavement when a

panic stop would
cause=
the wheels to lock up and bounce, chirping madly

every time they touched
t=
he ground. Those are also the ones where you had to

get out and set the
loc=
king lever in the tongue to allow you to back up

without actuating the
trai=
ler brakes.

Chip Bearden
ASW 24 "JB"
U.S.A.