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TISHX SUSPENSION SYSTEM

Steve Pierce said:
I am still running 3-4 psi in my Bushwheel but don't get in to any big rocks, just some washes and swells. What did Acme say about the scuffing?
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I did not get a response on it.
DENNY said:
Are the Airframes shocks using a Nitrogen charge like the ACME? I did not see a port anywhere on them in the pictures.
Thanks
DENNY
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I am not sure if Airframes shock is charged with Nitrogen. Maybe someone from Airframes will chime in here. I know the Airframes shock has preload on the spring and I know from my own experience disassembling the ACME there is really no preload on them. Both shocks are built to require no service at annual inspections from what I understand so I assume most people would never do any service on them. The ACME is easy to take apart and work on because there is no preload and the Airframes may also be easy to take apart and work on but I have not had one apart. I use to take apart the AOSS and do some work to them internally, they were under preload also so you needed a way to compress them to remove the spiral ring and disassemble. I would assume the Airframes you would also need a way to compress if you wanted to look inside.
 
I talked to Gabe today at Airframes. The new shocks do not have any way to adjust or add nitrogen to the shock. One less failure point.
DENNY
 
DENNY said:
BLACK-OPS-Instruction-Manual.pdf Page 8 has the yearly inspection instructions. I don't think I have ever seen anyone remove them for inspection unless the gear leg was dragging behind the cub on safety cables.:LOL:
DENNY
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Nothing internal in that inspection. The bushings are where they attach to the fuselage and gear.

I have maintained Acme and TK1 for several years. They do need to be serviced with nitrogen occasionally.
 
Mauleguy said:
I know from my own experience disassembling the ACME there is really no preload on them.
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Can you elaborate on this for the uninitiated? FWIW I understand suspension. I just haven't experienced it (by today's standards, in a cub much) if there is no preload, and no spri gs, what is holding the airplane up in a static state? I suspect the nitrogen pressure is the preload, and purging it to disassemble renders it 'unloaded' am missing something?

Thank you for weighing in on this thread, it is fascinating stuff for sure.

Take care, Rob
 
In most applications, a stiff spring that is essentially topped out inside the shock body allows the removal of the endcap without decompression. In practice this means when the shock comes off the airplane, the entirety of the static sag is removed allowing the endcap removal event to be less explosive.

Nitrogen is just used to displace air, which contains water and is the enemy. "Charging" a shock effects the valve stack, not the spring stack and when you remove the air from a charged shock, you are not changing its spring, rate, preload/sag, or the like. Note this is NOT the case for the TK1s which is an airshock; very different from the Acme's and I suspect the Airfames unit.
 
For those of you interested in some of the technical details of the Tishx with a bit of discussion around the purpose of nitrogen, Loni did a good interview here:


Greg, ask Loni if we can adjust preload and adjust rebound independent of the compression stack on the Tishx. He seems to know his bits from his bobs and must be a great resource for Airframes.
 
If there's any static sag the suspension pivots are constantly wearing. You want some preload to make the tires work a bit before moving the gear legs.
Prop clearance suffers with sag.
 
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Pivots at the head and foot of the shock itself? ACME and I suspect TK1 are all heim joints so that shouldn't be an issue, although I entirely agree with your points.

I compensate for lack of preload adjustment on my Acme by shortening the length when ordering the shocks. Crude, but it works. From the feel of their springs, I am guessing the spring is a progressive rate which has both pros and cons. (I could be wrong on that guess of course)
 
I see on Airframes site weight says 10 lbs per unit. Think the AOSS are 7 lbs 2oz. So slightly heavier.
May try a set on Cub or Husky with cub gear once there are some reports on them. AOSS work great with 35's for me, but sometimes always a better choice out there.
Time will tell once they are out and tested by more parties.
John
 
It's now an absolute mystery how Denny Thompson & Bill Ellis , Jack Wilson could have ever flown into some of the nastiest rock piles in Alaska with standard old piper hydrosorbs for 50 years each and over a100,000 hrs total Alaska time; with out gas filled shocks.???? Amazing stuff.
 
None of them switched to Airstreak or Bushwheels when they came available? VORs instead of GPS? Technology can be good. I had thousands of hours in a Clipper, then a Pacer. Then I bought a beater Super Cub and wore it out. Installed the AOSS and was like "Wow" I really like these. Now after putting a little time on my Acmes I am really going Wow. Went out Sunday after we had some rain the week before. The gravel bars were a little wet. I noticed where I would see skips in the gravel where I touched down there were not any. The airplane stayed stuck and brakes were more effective. Now I know I can grease a landing where there are no skips but those are not normally as short as I need them to be to get into some of the shorter spots. Weight out your mission and equip your airplane accordingly.
 
TurboBeaver said:
It's now an absolute mystery how Denny Thompson & Bill Ellis , Jack Wilson could have ever flown into some of the nastiest rock piles in Alaska with standard old piper hydrosorbs for 50 years each and over a100,000 hrs total Alaska time; with out gas filled shocks.???? Amazing stuff.
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Back then a super cub didn't cost $200,000. Bend one back then, not too big of a deal. If there's an affordable option for me to make daily operations more forgiving on my airframe, I'm taking advantage of it.
 
1934A said:
Back then a super cub didn't cost $200,000. Bend one back then, not too big of a deal. If there's an affordable option for me to make daily operations more forgiving on my airframe, I'm taking advantage of it.
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Affordable?
 
Back when I was a young fishing guide (1970's) most fly fisherman struggled to cast 50' honest feet, Scientific Anglers introduced the "Air Cell" lines and claimed they were 40% easier to cast because of their new much less friction........ Over the years they have improved the lines dozens of times , usually claiming 20/50% improvements to them. So in theory they are now around 400% better, so the same avg Joe should theoretically be able to cast this new lines easily 200' even if all their claims were halved......
Well in actual fact in my canoe after 50 years of taking folks out I have noticed that most fisherman still struggle to lay out 55/60 ft of line properly.
I can definitely draw a correlation to these flylines; to alot of these new products for Cubs, of course they are good and improved, and if you can afford $6000 shocks I think you should have them! But if you are convinced they will "save you" because of your inexperienced flying background......(bad theory). So in short if you are struggling to land in 300' with standard hydrosorb suspension, you probably will still struggle because of your inexperience.
Very few fisherman can cast 100/120 of fly line, Very few Cub pilots can land in no wind in 100/120'. Those two-factor will never change, regardless of the fly lines, or shocks they try.
It ain't the arrow, it's always been the Indian.......
 
It's hard to get stopped short if your wheels are not making contact with the ground and that is what all of these newer shocks help with. I could not believe the difference in Acme shocks and landing rough places. I am going to get a set of the new Ti Alaska Gear shocks for sure. I am with Steve, the newer shocks are game changers. I think even more so for a person that does not know their aircraft. Does it make a better pilot, probably not... With Acme it is hard to make a bad landing, and if all's you ever do is land in the grass or gravel strips probably not worth the extra money. If your mission is to land in challenging places off airport they are worth every penny. I know Kirk Ellis and have been to some of their working strips, they are not difficult. These guys are smart they would not take a working cub into a questionable place and land just to get a guy a big moose. They would find a place close by and hike in and build a good working strip pre-season. It is about being smart when you make your living with your airplane. Kirk also runs Acme's on his hulk so I am not sure what you are saying about the old timers because they like the advancement too. Paul Claus has the lightest best equipped cubs for working, they are not running 31" tires anymore or hydrosorb shocks.
 
As to adjustment of the new TISHX suspension system there is none that I know of other than the adjustment at the end of the rod for length. I know Loni and he is not just blowing smoke about this shock. I watched him testing it at gross weight one day fairly early on and it was a place he dug ditches to go through. He wanted a shock that worked both light and heavy!

​

 
I think the price of a Super Cub is pretty relative to the economy. I can't remember for sure but I think a new cub in 1979 was like 30K, I bought my first house for 30K in the early 80's. That same house today is 500K
 
I had contacted sales at Ak gear co, got a quote on shocks, inc safety cables. Made out a check, ready to mail, I had second thoughts.
Nobody asked me about gear length, empty weight etc. I called to request more info, was assured I’d get a call back “in 5 min”, nothing.. My other reservation:
Something about re-inventing a coil spring in a tin (Ti) can operating in extension (rather than compression) dosnt sit right with me, especially with no means for adjustment.
The principal goes against all the advancements in shock absorber technology.
Kudos to them for trying to raise the bar on this but I’ll wait till there’s some more user feedback.
Hopefully costumer service didn’t go away with the recent name change at AK gear co.
 
On & offroad shocks have used external springs with preload collars with independent adjustment for compression and rebound for thousands of years good reason - a spring swap for a different weight range outside of adjustable preload limits takes minutes and allows a single shock to become limitlessly customizable. I am not suggesting preload is a substitute for spring rate; simply stating that the ability to adjust preload allows for a larger window of optimal usage on the same spring.

For those of us that don't fly a Super Cub and are much lighter, a spring swap might be all that it would take to allow the same beefcake shock to work on little cupcake experimental -11. And, vice versa. (Yes, valving should be adjusted to compensate, hence my desire for external stack adjusters.)

My biggest complaint with the Acme shocks and stinger is it is too stiff for my application, even after sending it back twice. That said, it is 1000 times better than bungies, straight rate springs with no shock, and the rest, so my complaints are more nit-picky than a real complaint.
 
Tk-1 address all of these issues and far outperform anything else out there.
My opinion.
If someone were to seek STC approval on an existing design, TK-1 would have been the better route, though probably tougher to get approval as you couldn’t ride on the heels of Acme
 
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Oliver said:
Tk-1 address all of these issues and far outperform anything else out there.
My opinion.
If someone were to seek STC approval on an existing design, that would have been the better route, though probably tougher to get approval as you couldn’t ride on the heels of Acme.
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Everything Tony does is top notch, but I have unfortunately never attempted to set up his shocks/stinger for my little bird. Can rebound be adjusted on the TK1s? I imagine the compression and (psuedo)-sag can adjusted by nitrogen pressure?
 
Colorado-Cub said:
Everything Tony does is top notch, but I have unfortunately never attempted to set up his shocks/stinger for my little bird. Can rebound be adjusted on the TK1s? I imagine the compression and (psuedo)-sag can adjusted by nitrogen pressure?
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No springs, Nitrogen pressure and strut length adjustment controls sag. (Aircraft weight)
No dampening adjustment, dual shocks per side for redundancy if one fails
Over 800 hrs 3500+ off airport landings, some not so graceful, recharged (topped off) one shock once since installed.
Downside-non STC’d
And yes, Tony is top notch.
 
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