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Experimental Shock Options and Reviews

vj88

Registered User
Anchorage, AK
Hello,

I'm interested in your experience with different experimental cub, direct replacement shock options. The TK1 seems to be more prevalent in some of the cubs in Alaska but have heard good reviews of the Acme black ops shock as well. The TK1 (under 14 lbs) is reported to be a pound heavier than the Acme shock (under 13 lbs). Are those running these systems using safety cables as well? Does anyone have experience with both?
 
Always use safety cables. It not just the shock that fails. Keep hearing good about the TK1 from different people


Sent from my iPhone using SuperCub.Org
 
I run the TK1 and a couple buddy’s run the ACME shock...both are nice products that we each like, however I feel in the rougher stuff the TK1s are a bit softer/smoother ...my money remains on the TK1.
 
It's good to have two excellent systems available from two excellent suppliers. I like my TK-1s but have friends who say the same about their Acmes. Pick one and smile. The biggest smile comes after you screw up a landing and wince in anticipation of the big bang... and there is none. Very cool.

Yes on safety cables. That topic was covered well not that long ago by jrussell's broken cabane ear pictures.
 
I love my Acme Black Ops Gen 3 shocks. Top notch customer support from a company owned by veterans too. I have probably 200+ hours and 400+ landings on them—no bounce on even a no flair short field “arrival.” Highly recommended.

i ran a set of AOSS for about 300 hours and 500+ landings. The Acme shocks are a huge improvement over AOSS.
 
I love my Acme Black Ops Gen 3 shocks. Top notch customer support from a company owned by veterans too. I have probably 200+ hours and 400+ landings on them—no bounce on even a no flair short field “arrival.” Highly recommended.

i ran a set of AOSS for about 300 hours and 500+ landings. The Acme shocks are a huge improvement over AOSS.

I liked Ted's shocks so much I put a set of the Acme shocks on my lightweight PA-11 like airplane (obviously lighter spring and valving).

The Acme are not much heavier than my die-spring gear and work great even on low gross-weight Cubs.

(I blame Ted for my lighter wallet, too.)
 
Huge fan of TK’s. Acme, not so much.
Think Acme’s have been improved since this happend but that’s of little comfort to the poor fellow that wrecked his plane as a result.
“Veteran owned”? Veterans don’t hang their comrades out to dry.
Yes, strong words, but until the affected party has been made whole, I will continue to express my opinion when the question arises.


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Huge fan of TK’s. Acme, not so much.
Think Acme’s have been improved since this happend but that’s of little comfort to the poor fellow that wrecked his plane as a result.
“Veteran owned”? Veterans don’t hang their comrades out to dry.
Yes, strong words, but until the affected party has been made whole, I will continue to express my opinion when the question arises.


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I have seen this specific photo, but never did understand what happened here. Any more details on the load that caused it?

The eccentric spacers and fit with the Airframes heavy duty lower cabane V to the Acme shock left a bit to be desired on my install.

I did notice the possibility of a torquing action on the upper mount if the geometry of the installation was not perfect which did cause me to pause. The upper mount is fixed by the eccentric which means the arc of travel through the entire gear leg will have to be in perfect unison with the shock. I feared a failure to maintain the perfect arc through the gear travel would look like the above image...A simple heim joint at the top would solve this problem, but that is not how they are currently constructed.
 
I guess I don't inderstand how a compression load broke that gear like that? More details?

If you are running the Acme Black Ops 3 check the pressure from time to time. They are not trouble free like AOSS. I did the condition instpection on an FX3 Carbon Cub and the pressure had leaked down. Easy to check and air up. Turned out the valve core was the culprit. This pump is light and will fill the strut to 250 psi with no problem.
https://www.amazon.com/gp/product/B005543YUE/ref=ppx_yo_dt_b_asin_title_o00__o00_s00?ie=UTF8&psc=1
 
700+ hours on TK1's, thousands of landings. Nearly all off-airport. Two thumbs up.
 
Huge fan of TK’s. Acme, not so much.
Think Acme’s have been improved since this happend but that’s of little comfort to the poor fellow that wrecked his plane as a result.
“Veteran owned”? Veterans don’t hang their comrades out to dry.
Yes, strong words, but until the affected party has been made whole, I will continue to express my opinion when the question arises.


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Oliver, explain HOW these parts came to be broken? Because the folks on here don't know the whole story. Maybe you have a picture of where the plane was and what it was doing when this happened. Would there be an accident report, 3rd party, that we could read because that would’ve had to hurt breaking both shocks at the same time.
If the pilot was “off airporting” he frigged up going without safety cables, or, did they let go to?
Justify your picture.
 
The problem with better suspension is you’re going to abuse it more. When you are full stall at 20ft agl you’re going to tear something up.
There was a video on Facebook of a set of tk’s that were seized up. If you fly either of them the same way you fly bungees and aoss you will have no problems, and they are much much smoother. If you were to loose a seal on the acmes, you still have a spring to get you home. Loose one on tk’s and the air leaks out and you’re stuck.
https://www.facebook.com/groups/Bigtirepilots/permalink/866142240246232?sfns=mo

Sent from my iPhone using Tapatalk
 
I suspect the seized TKs you refer to were my nephew's. Early production shocks on a plane that gets worked harder than most. Tony repaired them and had already resolved the problem with coatings on newer production slide tubes. TK customer support is fantastic. I've swapped texts and calls with Tony after hours, on Sundays... he's been very responsive.

Lose a seal on one TK? You still have another shock. Lose them both? Fly home and land carefully. Any TK users had one go flat in the field? I haven't heard of any.
 
https://youtu.be/P71DMlKyy44

Like I said, you can break and anvil if you try. Everything has limits. Either shock is a huge improvement over bungees and hydrosorb. I think if you land the same way as on bungees you’re not going to break either of them


Sent from my iPhone using Tapatalk
 
Steve, shocks, (bungees too) are under an extension load, not compression.
Acme borrowed their design from a shock designed to work under compression load.
with obvious shortcomings.

What component failed in the previous video? Besides the pilots pre frontal cortex!
That appeared to be the equivalent of an 8’ static drop. Couldn’t tell if safety cables were installed,
And no prop strike. Two more thumbs up for TKs.
 
That picture of the failed Acme shocks was around on the previous thread on this topic. I talked to both Matt & Eric at Acme regarding the whole story behind the picture. They are stand up company owners. They WILL take care of you.
 
Steve, shocks, (bungees too) are under an extension load, not compression.
Acme borrowed their design from a shock designed to work under compression load.
with obvious shortcomings.

What component failed in the previous video? Besides the pilots pre frontal cortex!
That appeared to be the equivalent of an 8’ static drop. Couldn’t tell if safety cables were installed,
And no prop strike. Two more thumbs up for TKs.
Oliver, step up to the plate. If you can. Thanks
 
TK-1s have a slip tube assembly that allows the shocks to work in compression as the strut extends (the gear squats under a load). Just like Acme has gone through different "generations" of improvement, we've learned some things about TKs, too. Like how Vetterman tail pipes dump exhaust right on the shocks and promote corrosion and deposits on uncoated slide tubes. It's a simple maintenance issue but TK started coating the tubes to prevent the problem. My own tubes are uncoated. I keep a little Corrosion X on them and it seems to work well.

That Carbon Cub needs some Keller flaps. Landing at that AOA makes no sense on a maintained grass strip. You sure as hell wouldn't do it where TKs and big tires are intended to go. But, if that plane had bungees and hydrosorbs? The damage would have been much worse. Ditto for AOSS. That's a big hit with no rebound. Gas shocks rock!

Here's a pic of a fully extended gear. This was the result of no gas in the shocks but it illustrates how the TKs compress with gear extension. I flew my Cub for the first 5-6 hours with my struts too short, so no suspension. I was using the 35s for shock absorption and the safety cables (also too short) kept the gear up. Not a problem, even for a test pilot in a new plane.

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Is there any occasion where that sort of approach and drop in is actually needed? (Actually needed being key). Kind of a useless exercise. Fun to watch though!
 
It's more fun to watch float planes do it, or so a friend tells me. It wasn't so much fun from the driver's seat. ;)
 
[FONT=&quot][FONT=&quot]Exstreamly satisfied with our decision to go with the ACME product. Clean fit. Wonderful customer support. But to be completely honest all I have landed on off paved port is small river bed pebbles, nice grass fields and large open salt flats here in the southwest. All smooth surface. So never really pressed the limits of their design capabilities. Next build I will continue with the ACME.

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“Veteran owned”? Veterans don’t hang their comrades out to dry.
Yes, strong words, but until the affected party has been made whole, I will continue to express my opinion when the question arises.


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With all due respect. Please keep this philosophy in the certified market where it is welcome and belongs.

The owner of a new experimental aircraft purchases and tries out an experimental product, plays test pilot, and you are looking for compensation when the experiment goes contrary to your expectations? Hmm...
You might think that as a veteran, I am offended by your post, but I am not. I learned as a young Marine long ago, that I could, and would be tasked with protecting many with ideas and beliefs I could not reconcile. Never the less, the fact that one is entitled to a belief, doesn't make it a great one.
As to the original post, they're all great, but like any suspension, they must be matched to the load, and it's moment. While these are as 'plug and play' as it gets, you still need to be willing and able to make it all match up if you want to reap the most benefit. And as Tom so accurately stated, any of them can and will break...
Take care, Rob
 
With all due respect. Please keep this philosophy in the certified market where it is welcome and belongs.

Certified market where what belongs? What does that mean? Customer support isn't limited to the certified market. I have no ill will toward Acme or any other supplier and don't think the internet is the place to vent against a manufacturer but to the experimental parts suppliers that I've dealt with? Nothing but praise for excellent business ethics and strong customer support. TK, Backcountry, Garmin, Superior Air Parts, etc have all been top notch and none has hidden behind the experimental category to deny warranty or good service.

Wasn't there an old bash thread about those Acme shocks?
 
Awhile back when Acme shocks first appeared, myself and another regular on this site were quick to point out what appeared to be an obvious potential point of failure in the design.
Ironically, not long after, I was contacted by a third party with brief description and photo documenting component failure. “occurred during taxi over rough/uneven terrain” or words to that effect.
As I understand it, Gen 1 have been redesigned to correct the issue and Acme went so far as to “recall” gen 1’s with an offer to replace.

Disclaimer: all of this was based on 3rd party hearsay, However, when this photo surfaced in a previous thread Acme was quick to acknowledge the incident yet vehemently excused themselves of any responsibility, blaming the failure on poor discretion and pilot error. This is a landing gear component designed to replace time tested components and enhance off airport performance.
Unlike the TK Video, failure resulted in catastrophic damage.

I’m all about product development. However, if one engages in a FOR PROFIT endeavor to create and market something, they have a moral and financial obligation to stand behind their product when that product does not perform as implied. “experimental” category does not relieve the manufacture of responsibility as some have stated. This incident should have been a small hiccup in an otherwise well intended effort by some good people but, in my opinion, has unfortunatly, been grossly mishandled.
 
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Steve,
i am not an engineer, nor was I present when failure occurred.
my opinion: considering everything else remained intact, mounting bolts should have been the weakest link, at least they were with bungee set up.
 
[FONT=&quot][FONT=&quot]Not to do a major shift from the initial question asked - I would like to add that for all the different main gear experimental and certified suspension plug and plays out there- adding change to the tailwheel spring has truly completed my touch points. [/FONT][/FONT]
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[FONT=&quot][FONT=&quot]Typically the traditional tailwheel x 3 steel spring system transfers energy into the airframe. No way around that fact. Normally there is little doubt that the tailwheel is on the ground. I have found this is NOT the case with the newer designs both from ACME and Airframes Alaska for the experimental market. [/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
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[FONT=&quot][FONT=&quot]I am currently running the T3 product and after 100 hrs I have yet to feel that point when the tailwheel makes contact with the ground. During a main wheel gear landing I have purposely pulled back hard on the stick as the tail is starting to stop flying to plant the tailwheel and received ZERO airframe vibrations. I mean ZERO. [/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
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[FONT=&quot][FONT=&quot]My 2 Pesos. If you want the complete suspension do not forget the tailwheel.

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Awhile back when Acme shocks first appeared, myself and another regular on this site were quick to point out what appeared to be an obvious potential point of failure in the design.
Ironically, not long after, I was contacted by a third party with brief description and photo documenting component failure. “occurred during taxi over rough/uneven terrain” or words to that effect.
As I understand it, Gen 1 have been redesigned to correct the issue and Acme went so far as to “recall” gen 1’s with an offer to replace.

Disclaimer: all of this was based on 3rd party hearsay, However, when this photo surfaced in a previous thread Acme was quick to acknowledge the incident yet vehemently excused themselves of any responsibility, blaming the failure on poor discretion and pilot error. This is a landing gear component designed to replace time tested components and enhance off airport performance.
Unlike the TK Video, failure resulted in catastrophic damage.

I’m all about product development. However, if one engages in a FOR PROFIT endeavor to create and market something, they have a moral and financial obligation to stand behind their product when that product does not perform as implied. “experimental” category does not relieve the manufacture of responsibility as some have stated. This incident should have been a small hiccup in an otherwise well intended effort by some good people but, in my opinion, has unfortunatly, been grossly mishandled.
Oliver, you’re taking a shot at a small, hard working outfit with a great reputation. You have posted a picture of damage you acknowlege came from “3rd party hearsay.” You were not a witness to this “taxiing over rough terrain” event. Was anyone else there beside the pilot?
Don’t you see a problem with what you’re saying?
 
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