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TK1 vs. Acme Aero (SEP 2020)

Back to Post 87. I was there, about 150 feet from where that plane had a "maximum extension" and I was part of the group that looked at that plane after. NOT A trace of damage to the undercarriage. (and it did not bounce 1 inch)

I have personally tested both the TK1s and the ACMEs on my cub, and I mean TESTED! and for the record, as of today I have ACMEs on the plane. The TK1s are amazing and are lightyears above anything I could imagine coming from coil springs, and I never had a single issue with durability or failure. The ACMEs are just as capable and in my application about 3lbs a side lighter, that is how I made my choice. YMMV, everyone has an opinion, just ask Dooley!
 
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🤦
Dooley isn’t even on here and he gets mentioned. Nooooo, don’t ask Dooley!! [emoji849][emoji38]


Sent from my iPhone using SuperCub.Org
 
I appreciate this thread, and if I ever need to fix my gear, I will likely replace it with the AOSS (certified) system.

Is there a general life limit on hydrosorbs? AFAICT, they were last replaced by the Italians in the 70s (it's an L21B).
 
I check the hydrosorbs when I install new bungees to see if they have any resistance. The idea was the shock was suppose to reduce the rebound.
 
Local guy bought an early model backcountry cub with TK1's a couple of years ago. I did his Tailwheel endorsement in it. When I signed him off, I told him "don't ever fly a bungee Cub with out flying with me first". The issue was we never had a bounce that he had to decide how to recover from. We made some horrendous arrivals and landings and that airplane just stuck to the ground. Cool!
 
Thread on Facebook about landing gear systems. I noticed Sir Dooley has TK1's on his cub. His dog/copilot must approve. As I'll be flying my labrador copilot, I have to live up to the highest scrutiny!
 
Local guy bought an early model backcountry cub with TK1's a couple of years ago. I did his Tailwheel endorsement in it. When I signed him off, I told him "don't ever fly a bungee Cub with out flying with me first". The issue was we never had a bounce that he had to decide how to recover from. We made some horrendous arrivals and landings and that airplane just stuck to the ground. Cool!

Like people who have only driven AWD vehicles in snow, can't drive a 2WD in snow, don't know all the tricks. Interesting, PIO's on a blown touchdown may be a thing of the past?
 
Like people who have only driven AWD vehicles in snow, can't drive a 2WD in snow, don't know all the tricks. Interesting, PIO's on a blown touchdown may be a thing of the past?

I'm working on a version you can repack after every landing. Should make it easier for folks.

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So a friend I fly with regularly called me today. He lives in Texas and has a place in Idaho where his EX2 has been for a bout a month. Got there and one of his TK1s had leaked and airplane was leaning pretty good. Luckily through our Super Cub network I texted someone who sent me contact to someone on the field with a nitrogen bottle and regulator go get him going. Something else to think about I guess. I had a good talk with Tony who explained how to service them and what to check and how on inspections.
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Any idea how often the nitrogen charge on an Acme or TK1 system would need to be checked/serviced or is that an "it depends" question? AOSS seems relatively maintenance free, even if it doesn't provide the same degree of shock absorption.
 
Any idea how often the nitrogen charge on an Acme or TK1 system would need to be checked/serviced or is that an "it depends" question? AOSS seems relatively maintenance free, even if it doesn't provide the same degree of shock absorption.

I check the Acme's during annual. Nice thing with the acme is even if the nitrogen leaks out it doesn't deflate like the above pictured carbon cub
 
When you recognize more than your "normal" squat it indicates shock pressure is down. It's never happened to mine. I've played with pressure to find what I like best but once set it's stayed there, even after a year of inactivity.

One thing several TK-1 users are doing, including me, is to reduce shock pressure a little and add some tire inflation pressure. That induces a little squat. All the advantages of the good suspension and shock absorption with easier rolling. I'm pretty sure that's what you're seeing in some of the pictures you see of a well known yellow and gray Carbon Cub. And as already mentioned, having some drop-out is a good thing on rough ground. Otherwise you bunny hop over irregularities.
 
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I was wondering why I was seeing that squat in all the pics. I find myself running the bushwheels harder with the AOSS also makes moving the plane a lot easier and takeoff is better.
DENNY
 
Any idea how often the nitrogen charge on an Acme or TK1 system would need to be checked/serviced or is that an "it depends" question? AOSS seems relatively maintenance free, even if it doesn't provide the same degree of shock absorption.

I can’t speak to Acme, no experience with them.

Re TK1’s
Tony asked for my typical flying weight, empty weight, and gear length.
Shipped them with 90 psi (if I recall)
I installed them right out of the box 800 hrs ago and , aside from occasional clean and lube moving parts, haven’t touched them since.
 
Probably more like 160-170-180#. Mine are at about 190# now on the longer gear.

Mine weren't charged when I got them. It surprised me. No problem, just unexpected.
 
Oliver, have you used zip ties on the lower strut shaft to measure your shock travel? It's the gauge for setting shock pressure for the airplane weight and use. I think 4" is the target but I'd have to dig up old texts to verify. If you aren't set up for full travel you give up one of the TK-1 performance advantages.

FWIW, TK also makes a single shock that uses and internal coil spring. https://store.tk1racing.com/SearchResults.asp?Cat=237

Serious question for Acme users. How much shock length is determined by gas pressure? Can you release pressure to soften the suspension for light ops and increase pressure to maintain airplane height for heavy ops? I don't know anything about internal spring gas shocks. I know a fair bit about external spring gas shocks, and spring adjustment is how we adjust height with those.
 
Crickets!
Kinda what I got when I asked you about your engines that had major metal contamination and everything had to be replaced.

I checked pressure on the early aluminum schrader valves and found no pressure on one. Was riding on the spring. No change it height. When I pressured it up it sure helped the rebound.
 
Stewart,
havnt played with pressure on TK1’s. Gear stance is pretty normal when parked at current pressure.
Im running 31’s pretty low for more contact area for braking. Not feeling much rebound at current setting but I see your point. Ill try the zip tie trick, maybe fool around with pressures a bit.
thanks
Doug
 
I will answer but I am not an expert by any means. The shocks only have a small adjustment at the heim. If that is not enough you can send the shocks back in and have them lengthened or shortened by changing the rod out. They can also change other things inside the shock to be more custom to your type of landings. So if you don't like how your ride is or the length you can send them in and they will turn them around in about a day according to Matt. I liked the ride right out of the box, zero rebound from what I can tell. I did not like the length so I made my own adjustment to that in my machine shop, still playing with how I want the airplane to sit static. The Javron gear is not the same as Airframes or Atlee Dodge so mine were to long. I bought them from a guy in Alaska who had never installed them on a narrow body cub with I think Atlee gear. If you have a large envelope from light to heavy you may see the gear tucked in more than you like or splayed out but that is only a guess at this point since I have not loaded the airplane to gross weight. Need to play with that and see where the happy medium is for that also. So the answer is no I believe to changing the ride height by airing them up or down but I personally would not want to have to do that anyway PIMA. I love them and for what it is worth the machine work is top notch. I don't like the looks of the monster shock double thing and how it is assembled with the exposed slider. I have only flown them once on Mike Olsens cub and never put them to any test so other then landing in the back country of Idaho at a few spots I have no experience in the off road world. If I did I might think they were the best, lots more choices now then a while back and that is nice. I have the Black Ops Gen 4 and I am a fan at this point and I have landed and hit things with them and been surprised at how smooth they are even with more pressure in the tire then I usually run in my 35" tires. It use to be the tire doing the work now it is the shock.

https://www.youtube.com/watch?v=P9lMZSNLvfA
 
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I will answer but I am not an expert by any means. The shocks only have a small adjustment at the heim. If that is not enough you can send the shocks back in and have them lengthened or shortened by changing the rod out. They can also change other things inside the shock to be more custom to your type of landings. So if you don't like how your ride is or the length you can send them in and they will turn them around in about a day according to Matt. I liked the ride right out of the box, zero rebound from what I can tell. I did not like the length so I made my own adjustment to that in my machine shop, still playing with how I want the airplane to sit static. The Javron gear is not the same as Airframes or Atlee Dodge so mine were to long. I bought them from a guy in Alaska who had never installed them on a narrow body cub with I think Atlee gear. If you have a large envelope from light to heavy you may see the gear tucked in more than you like or splayed out but that is only a guess at this point since I have not loaded the airplane to gross weight. Need to play with that and see where the happy medium is for that also. So the answer is no I believe to changing the ride height by airing them up or down but I personally would not want to have to do that anyway PIMA. I love them and for what it is worth the machine work is top notch. I don't like the looks of the monster shock double thing and how it is assembled with the exposed slider. I have only flown them once on Mike Olsens cub and never put them to any test so other then landing in the back country of Idaho at a few spots I have no experience in the off road world. If I did I might think they were the best, lots more choices now then a while back and that is nice. I have the Black Ops Gen 4 and I am a fan at this point and I have landed and hit things with them and been surprised at how smooth they are even with more pressure in the tire then I usually run in my 35" tires. It use to be the tire doing the work now it is the shock.

https://www.youtube.com/watch?v=P9lMZSNLvfA

Mauleguy sounds like you built another Javron cub? How about some details on what you did different than the last one and comparisons? Also what’s different about the Javron gear? Always appreciate your input and real world experience!
 
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Yes, Narrow body, O-320 with 10-1 pistons, 35" bushwheels, electric system but no starter, 3" extended Javron gear, Baby bushwheel, Fineline seats from Anchorage,
Borer prop pitched 41, Acme gen 4 shocks, Superflight fabric and paint.

Javron gear is built 3" extended but not wider so than stock so it has shorter strut lengths then Airframes and Atlee
 

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To add a little more detail about the difference between the last one, which was a wide body with extended squared off wings and long double slotted flaps. Hard to compare the two.

Wide body Cub flew slower but was not as sporty, hard to beat the handling of a stock cub wing.
Narrow body feels much lighter in the tail then the wide body cub but it has been a while since I flew a cub and tried to land short. It seems to leap off the ground but landing rolls right now seem long in comparison to Bushwacker where I can almost land with the brakes locked. I also flew Bushwacker almost a 100 hours in September so I was pretty tuned up by the time I got home from Moose hunting.moose.jpgbushwacker.jpg
 

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I have been in Arkansas playing, not flying as much as I would have liked but a good time none the less. In my down time I got to thinking about this adjustability of the shock length. Is the pressure adjustment to change length on the TK1 as the trun buckle is on the AOSS and the Heims joint on the Acme?
 
Primary strut length is determined by the main tube. My first gear took two tries to get it right and the long gear was perfect. All three sets of tubes have two length holes drilled. A bolt near the top of the assembly captures the hole to establish length and an adjustable rod end allows fine tuning. My rod ends are screwed all the way in. I think Tony allows 1/2" of threads to show. You can adjust struts to keep tires vertical with whatever pressure you prefer. Or add/decrease pressure as needed and let them splay a little when soft.
 

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