Today's Message Index:
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1. 12:46 AM - Re: Re: Yak-18T main LG shocks air/oil filling procedure (Richard Goode)
2. 06:52 AM - Re: Yak-18T main LG shocks air/oil filling procedure (Vic)
3. 02:24 PM - Re: Re: Yak-18T main LG shocks air/oil filling procedure (Michael Wikstrom)
4. 05:53 PM - Yak 52 fuel primer pump (Steven Johnson)
Message 1
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| Subject: | Re: Yak-18T main LG shocks air/oil filling procedure |
Hello Michael,
We have digitised all the manuals that we can find about the 18 T and
will later send you the links to download them, and you could well find
the information that you need there!
With regards
Richard
PLEASE NOTE NEW EMAIL ADDRESS.
RICHARD GOODE AEROBATICS
Rhodds Farm, Lyonshall, Hereford, HR5 3LW, UK
Tel: +44 (0)1544 340120
e-mail: richard@rgaeros.com <mailto:richard@rgaeros.com>
www.rgaeros.com <http://www.rgaeros.com/>
WORLD LEADERS IN EAST EUROPEAN & CHINESE RADIAL AIRCRAFT ENGINES
In partnership with Aerometal Kft, Hungary.
From: owner-yak-list-server@matronics.com
<owner-yak-list-server@matronics.com> On Behalf Of michael@wikstrom.cc
Sent: 28 July 2024 22:47
Subject: Re: Yak-List: Re: Yak-18T main LG shocks air/oil filling
procedure
Hi Vic,
Thanks for your recent input on my shock issues.
I've checked the main gear pressure, both bottom and top.
The bottom part has 65 kg/cm2 and the top part has 18 kg/cm2
The front shock has bottom 70 Kg/cm2 and top has 20 K/cm2 - This shock
works fine.
I've not checked for oil yet.
What I don't understand is, with the aircraft empty (60L+60L fuel) with
no-one inside, the main gear shocks are half compressed, and she is
sitting statically at quite an angle, to the rear.
If I measure the ''shiny'' part of the shock, which when on jacks,
measure 290mm, goes down to about 200mm when the jacks are removed.
If I fill up fuel and put 2 persons inside, the shocks compress almost
completely.
What I'm wondering is, that as my aircraft is an earlier model yak18t
(1979), maybe I'm, using the wrong pressure settings? Maybe the top
part should have higher than 18 Kg/cm2?
I got the readings from the only yak18t description manual that I have.
Vic, can you confirm that it is pressure in the top part that determine
the static position of the aircraft?
Note that I have no visible oil leaks, and no pressure leaks either
Thanks for any input that might help
Michael Wikstrom
Yak18T =93 F-HMSS
On 2024-07-09 16:59, Vic wrote:
<mailto:vicmolnar@aol.com> >
Hi Michael,
there are two places for pressurizing the lg struts: You checked the
bottom filling valve but that is just for extra hard landings when a
second piston gets active, which is sitting in the top of the hard
chromed inner telescope. This filling does nothing for the standing
height. Look way up at the painted outer section of the lg strut, there
is another filling valve next to the brake hose, see photo below. There
you can add oil or change it by fully compressing the strut to get old
oil out. Don=C3=82=C2=B4t know about the amount of oil but you found
some numbers. Anyway, at the top filling valve you can add some more
air, nitrogen no real argument. But don=C3=82=C2=B4t do excessive
pressure, it would give you a harsh ride. I=C3=82=C2=B4d want some angle
in the brackets that align the wheels for parallel tracks.
In case you disassemble the whole landing gear I=C3=82=C2=B4d suggest
to bin these old felt seals at bottom , they collect a mass of dirt and
lead that into the strut and destroy bushes and hard chrome. Better have
real dirt wiper seals there, like on motor bike teles, saves you
precious hard chrome restoration costs.
cheers
Vic
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Message 2
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| Subject: | Re: Yak-18T main LG shocks air/oil filling procedure |
Hi Michael,
the air pressure numbers look a bit low at below 20 bar, maybe from a Yak 18 two
seat. We did fill up a 18 T two years ago, but just cared for stand height,
no worry about numbers. You fill up more than required and only by testing and
wiggle on wings and later reduce air in small amounts for some angle in linkage
at the tele. You dont want all straight up, too stiff on the ground, see my
photo. The two pressures inside are separated by a piston in the chromed tube.
The high pressure side is only acitve at high bumps from heavy carrier landings,
when that piston moves down from the excessive pressure rise in the low pressure
system that you fill up at the top valve way up the gear. So just fill
up at the top valve for stand height, no matter what numbers say, for your aircraft
conditions in use.
Take care for dirt on the chromed teles, there is only a felt "seal" , that
does not seal much but instead collects loads of dirt that ruins bronce bushes
inside and scratches the hard chrome. So only help is clean all the time once
you see dirt collected. For having a real seal and dust wiper you have to disassemble
the complete landing gear, a bigger job but no rocket science. Standard
seals inside are common o-rings, not great. Today Id go for hydraulic type
PU seals when available at these sizes.
cheers
Vic
P.S.: In second photo below your Yak in Thannheim - with mag troubles ??
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=513745#513745
Attachments:
http://forums.matronics.com//files/18_t_in_thannheim_2005_kkk_207.jpg
http://forums.matronics.com//files/p1110625_kkk_241.jpg
Message 3
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| Subject: | Re: Yak-18T main LG shocks air/oil filling procedure |
Thanks Vic, I'll let you know how it goes
Thanks
Michael Wikstrom
Yak18T F-HYMSS
-----Original Message-----
From: owner-yak-list-server@matronics.com
<owner-yak-list-server@matronics.com> On Behalf Of Vic
Sent: Monday, July 29, 2024 3:52 PM
Subject: Yak-List: Re: Yak-18T main LG shocks air/oil filling procedure
Hi Michael,
the air pressure numbers look a bit low at below 20 bar, maybe from a Yak 18
two seat. We did fill up a 18 T two years ago, but just cared for stand
height, no worry about numbers. You fill up more than required and only by
testing and wiggle on wings and later reduce air in small amounts for some
angle in linkage at the tele. You dont want all straight up, too stiff on
the ground, see my photo. The two pressures inside are separated by a piston
in the chromed tube. The high pressure side is only acitve at high bumps
from heavy carrier landings, when that piston moves down from the excessive
pressure rise in the low pressure system that you fill up at the top valve
way up the gear. So just fill up at the top valve for stand height, no
matter what numbers say, for your aircraft conditions in use.
Take care for dirt on the chromed teles, there is only a felt "seal" ,
that does not seal much but instead collects loads of dirt that ruins bronce
bushes inside and scratches the hard chrome. So only help is clean all the
time once you see dirt collected. For having a real seal and dust wiper you
have to disassemble the complete landing gear, a bigger job but no rocket
science. Standard seals inside are common o-rings, not great. Today Id go
for hydraulic type PU seals when available at these sizes.
cheers
Vic
P.S.: In second photo below your Yak in Thannheim - with mag troubles ??
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=513745#513745
Attachments:
http://forums.matronics.com//files/18_t_in_thannheim_2005_kkk_207.jpg
http://forums.matronics.com//files/p1110625_kkk_241.jpg
Message 4
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| Subject: | Yak 52 fuel primer pump |
Does anybody have a schematic drawing of the Yak 52 fuel primer? I have a new one-ring
from M14P but I cant figure out how to position it and make the pump functional.
Steve
Sent from my iPadOS
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