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Fortysix12
01-01-2011, 09:56 AM
Does anybody know the exact maximum extended stock hydrasorb lenght? This measurement could be taken from the shock dampener uninstalled as well. Running some calculations on the landing gear geometry and travel stroke distances as well as what happens to the gear movement when this demension is changed or lengthened. .

mike mcs repair
01-01-2011, 11:40 AM
.....what happens to the gear movement when this demension is changed or lengthened. .

it hits strut fork bolt and pushes bolt/bracket up or dents gear......

Fortysix12
01-01-2011, 08:32 PM
You wouldn't have the lenght of the extended dampener would ya there Mike?Got one laying around the shop. Question is how much longer or farther can it travel before a conflict like the one you have just reminded me.

mike mcs repair
01-01-2011, 09:56 PM
You wouldn't have the lenght of the extended dampener would ya there Mike?Got one laying around the shop. Question is how much longer or farther can it travel before a conflict like the one you have just reminded me.

i don't know, no spares laying around here....

i do know the AOSS is a bit too long, they want you to turn the strut fork bolts upside down with nut on top.... which sucks....

because if you bend a strut in the field, then you must somehow support plane(not by wing if you are trying to remove that bent strut) and get rear gear leg/bolt out of way so strut bolt can be removed to replace lift strut........

Fortysix12
01-02-2011, 07:32 AM
Mike that's a very important piece of information. Then what I design should hold the limit to within that point. I don't want to turn my strut bolts around. My new shock dampeing struts will have maximum travel up to that point.

tempdoug
01-02-2011, 01:29 PM
There is an AD or notice somewhere to have the right strut fork bolts. Regular a-n bolts are to long so theres a Piper part numbered bolt that is required to be used. Ive seen a lot of cubs running around with the wrong strut fork bolts.

tempdoug
01-02-2011, 01:44 PM
Theres some airplanes running around with the wrong strut attach bolts. The ones to use are piper 13241-00. Try this www.supercub.org/phpBB2/viewtopic.php?t=11085

mike mcs repair
01-02-2011, 02:13 PM
There is an AD or notice somewhere to have the right strut fork bolts. Regular a-n bolts are to long so theres a Piper part numbered bolt that is required to be used. Ive seen a lot of cubs running around with the wrong strut fork bolts.

And in the 90s they made them too long for a while also.....

Steve Pierce
01-02-2011, 08:43 PM
Piper quit making them and used an NAS bolt with a longer threaded portion. Caused lots of problems. The special bolt has a shorter threaded area since the bolt is in shear and no threads in the fork area. Service Bulletin 1172A.

http://www.piper.com/company/Publications/SB%201172A%20Lift%20Strut%20Attch%20Bolt%20Insp.pd f

DW
01-03-2011, 12:11 AM
The question is travel length not bolt used.

mike mcs repair
01-03-2011, 01:49 AM
The question is travel length not bolt used.

answer was.....

no longer then original hydrosorb shock... or it hits bolt.... especially if wrong bolt...

its all related...

DW
01-03-2011, 01:58 AM
and how long is original?

mike mcs repair
01-03-2011, 02:05 AM
and how long is original?


i don't know, no spares laying around here....

..................

Steve Pierce
01-06-2011, 08:27 AM
5" to 5-1/8" from the ones I have lying around.

DW
01-06-2011, 01:23 PM
Thanks Pierce your a peach!

Fortysix12
01-06-2011, 09:41 PM
So, the maximum extended stroke of a hydrasorb is 5 inches + or -, and any longer may damage some bolts,or not. Cool. Next question is what does that look like when viewing a gear that has almost reached that position. I would suppose the bungees are the limiting factor but if you bottom out a hydrasorb at the 5 inches, then the little quarter inch stread takes the hit and that doesn't seem like a lot to hold that kind of damage.Because I've never heard of the hydrasorb having this kind of damage 5 inches must be more than enought. The one major difference and advantage of the original hydrasorb over the spring gear is the bungees dont' move when airplane is loaded out to 1900 pounds where as the spring gear will move just by pushing up on the strut with my index finger. The main design function should not allow the gear to break under a static load and not compress beyond 5 inches. I would next like to do some pull loads of a stock gear with new bungees and plot it the info on graph beginning with static break load to what the final stretch load is at around 4 inches. Make sense?

Iflylower
01-06-2011, 10:02 PM
:up:up:upGo get 'em 46! Sound like you're running with new suspension design.:up:up :up

Fortysix12
01-07-2011, 07:46 PM
Well I just can't get those dirt track race tracks that sail through the air and land flat with out the least bit of bounce. I'm thinking a landing gear dampener should be able to perform like this. Consider rolling the trim forward on final aproach and at two fee above the runway you just let go of the stick, the airplane noses over contacts the runway and pegs a wheels landing hands free, why can't that be achieved. or at least close. AOSS? I think hydraulic/nitrogen is the best approach. Nothing ventured nothing gained.

Steve Pierce
01-07-2011, 09:42 PM
AOSS and AK Bushwheels.

Fortysix12
01-09-2011, 05:01 PM
Steve,

You are most likely correct.

Got have some fun though. There's a lot to know when designing an experimental shock strut. The Spring gear works ok but I want dead. I put the spring gear through it's paces this weekend transitioning a young friend to the taildrag world. It's pretty tough.

Gordon Misch
10-30-2012, 03:46 PM
5" to 5-1/8" from the ones I have lying around.
Steve, Would that be between hole centers, or overall?

mike mcs repair
10-30-2012, 04:09 PM
just happen to have one sitting here..

picture worth a 1000 words ;-)
click for bigger
9120
9121

Gordon Misch
10-30-2012, 04:19 PM
Thank you, Mike.
Looks like 5" of rod exposed, so 5" travel. That's assuming the tape measure isn't moved between the two pictures? That would be consistent with the 16 3/4" length for p/n 10566-6 in the other thread I started re the cover length.

Could you please confirm my assumption about the tape measure not being moved between pics?

mike mcs repair
10-30-2012, 05:05 PM
Could you please confirm my assumption about the tape measure not being moved between pics?

tape did not move

spinner2
10-30-2012, 05:11 PM
So this brings up a question I'm having right now. What would be the amount of travel you would want before a safety cable became tight? How much slack should there be, maybe 3-4 inches?

Gordon Misch
10-30-2012, 05:16 PM
Perfect. Thank you much, Mike!!

Gordon Misch
10-30-2012, 05:17 PM
So this brings up a question I'm having right now. What would be the amount of travel you would want before a safety cable became tight? How much slack should there be, maybe 3-4 inches?
I'd think just slightly more than the maximum travel of the primary suspension. So in the case of hydrasorbs 5 1/2" maybe - -

mike mcs repair
10-30-2012, 05:39 PM
I'd think just slightly more than the maximum travel of the primary suspension. So in the case of hydrasorbs 5 1/2" maybe - -

yup.... and the cables will stretch some as the cable ends elongate

skywagon8a
10-31-2012, 07:19 AM
12 Geezer: That does look like 5" exposed however it looks as though the lower part (in the picture) slides over the upper part. Thus there is some travel before the rod starts to be exposed. So the correct answer would be 5" plus the amount of motion before the rod is exposed. Did I say this correctly so that you understand what I mean?

mike mcs repair
10-31-2012, 07:21 AM
12 Geezer: That does look like 5" exposed however it looks as though the lower part (in the picture) slides over the upper part. Thus there is some travel before the rod starts to be exposed. So the correct answer would be 5" plus the amount of motion before the rod is exposed. Did I say this correctly so that you understand what I mean?

theres a big rubber washer in that space, well or I should say they start off life with it.... if I am reading your post right...

skywagon8a
10-31-2012, 07:46 AM
mike can you show another picture with the hydrosorb collapsed with the tape measure? If there is supposed to be a rubber washer in there should there be allowances for wear since the total travel would then be greater?

mike mcs repair
10-31-2012, 09:54 AM
mike can you show another picture with the hydrosorb collapsed with the tape measure? If there is supposed to be a rubber washer in there should there be allowances for wear since the total travel would then be greater?

well.. i tried ... but i cannot compress that one all the way.. rod is bent, have a new shock sitting here waiting to get installed ;-)

Gordon Misch
10-31-2012, 09:12 PM
Skywagon, I see what you're saying. However I'm inclined to hang my hat on these consistencies:

The piper dwg that gives 16 3/4" as the length of the cover,

The last post on the other thread indicates 16 3/4" measured on that installation,

In Mike's photos, the hydrasorb is fully extended, and the outside to outside measurement on the bolt heads is also consistent with 16 3/4". So it it seems the extended length of the hydrasorb is established, though the compressed length (which we don't care about for purposes of cover size) is open to question.

Thanks for noticing that in the pic though - I'd missed it.