TacAero suspension test: Stock bungees, AOSS, TK1, and Acme "Black Ops" Gen3

[Springloaded]

You and Glenn better hush your mouth with all this EX 3 trash talking, or I may have to do something about it with that Mark guy who hangs around and takes our money And that Chuck guy from Jupiter is no help with that red Jezebel he keeps popping up with.

Jim

I don’t know about the yellow part🤦Mines Gonna be Candy Apple Red
Mark should have a order form handy.

[raisedbywolves]

You and Glenn better hush your mouth with all this EX 3 trash talking, or I may have to do something about it with that Mark guy who hangs around and takes our money And that Chuck guy from Jupiter is no help with that red Jezebel he keeps popping up with. I dont sleep well as it is. And now Dan has an opening this summer to build.....
Does Judy like a little silver with the yellow? And JB said she liked it except she needs a blanket

Jim

Jim, if it makes you feel better I have an opening to build glenn an ex-3 this summer.
I think it would be a great compromise between a carbon cub and a 180, speed wise


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[Tim Rice]

I agree with everything TacAero has stated their review of the above shocks. I have had AOSS, Gen 2’s and Gen 3’s.
The only thing I will add is the complete failure of a set of Gen 2’s that resulted from a product failure. ACME express shipped me a set of Gen 3’s and promised they would get to the bottom of the issue. Alot was promised as far as answers for the failure of the product, but in the last month it has been radio silence. My shocks actually snapped on a routine takeoff on skis and my cub was only saved from major damage by safety cables. Most likely they had snapped prior to this takeoff and just failed as they flexed on this particular takeoff.

I would suggest that any owners of Gen 2 shocks to get in touch with ACME and follow up on the issue to get actual results of their data. They will likely imply user abuse an possible side load issues. This is simply not the case. I just don’t want anyone else to have to endure landing with on gear leg hanging straight down or get hurt . I given them ample time (2 months), to get to the bottom of this . It may be that this failure was related to flying skis and the blunt force that the shocks endure not having the luxury of bush wheels absorbing the initial energy. This is past my pay grade, and I am just passing on what I know in the name of SAFETY.

I will also add that I am EXTREMELY impressed with the GEN 3 shocks . The TachAero review is spot on, and they seem to have been engineered with the flaws of the Gen 2’s in mind.


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[Tim Rice]

I agree with everything TacAero has stated in their review of the above shocks. I have had AOSS, Gen 2’s and Gen 3’s.
The only thing I will add is the complete failure of a set of Gen 2’s that resulted from a product failure. ACME express shipped me a set of Gen 3’s and promised they would get to the bottom of the issue. Alot was promised as far as answers for the failure of the product, but in the last month it has been radio silence. My shocks actually snapped on a routine takeoff on skis and my cub was only saved from major damage by safety cables. Most likely they had snapped prior to this takeoff and just failed as they flexed on this particular takeoff.

I would suggest that any owners of Gen 2 shocks to get in touch with ACME and follow up on the issue to get actual results of their data. They will likely imply user abuse an possible side load issues. This is simply not the case. I just don’t want anyone else to have to endure landing with on gear leg hanging straight down or get hurt . I given them ample time (2 months), to get to the bottom of this . It may be that this failure was related to flying skis and the blunt force that the shocks endure not having the luxury of bush wheels absorbing the initial energy. This is past my pay grade, and I am just passing on what I know in the name of SAFETY.

I will also add that I am EXTREMELY impressed with the GEN 3 shocks . The TachAero review is spot on, and they seem to have been engineered with the flaws of the Gen 2’s in mind.


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[John Hodges]

Acme is pursuing answers to questions raised by Tim’s Gen2 failure. The failed strut was first analyzed by a suspension dynamicist who determined that the failure resulted from an impact load applied to the leading edge of the shaft above the threaded portion. No analysis has suggested a side load condition. The investigation has not ended there. Acme is seeking a second opinion. The strut is scheduled for testing and analysis by a prominent metallurgical test lab. That testing has not yet occurred due to project backlog at the lab.

All involved acknowledge and share Tim’s safety concerns. Safety is priority one with Acme, and it wants to ‘get to the bottom of this’ with all deliberate speed. For perspective, it is important to note that there are approximately 200 Acme Gen2 installations, many of which have endured long term rugged use (only a handful are now on CubCrafters products) and this is the first time Acme has seen anything like this. Acme strut manufacturing is ISO 9000 compliant, and Acme uses the finest materials available. We appreciate Tim’s enthusiastic endorsement of the Acme Gen3 “Black Ops” struts, but superior quality and performance of the Gen3 struts does not mean that the Gen2 edition is flawed.

Gen2 owners should feel free to act on Tim's suggestion to contact Acme, or CalCubs.

[turbopilot]

Acme is pursuing answers to questions raised by Tim’s Gen2 failure.

I am not a structural engineer, just an informed observer. It seems to me the problem here is that folks are trying to find ways to patch an old, very crude, Cub landing gear system to get better performance.

Most, if not all aircraft landing systems using shock absorbers perform their heaviest work in the compressed state, not the extended state, as found in bungee, AOSS or shock absorber fixes for the antique Cub landing gear design.

The result is these devices are seeing very high loads when nearly fully extended imparting significant moment arm bending on the associated structures. Given the restrictions associate with the old design of the Cub landing gear this is the only way to absorb the energy associated with landing loads. But it is not the best way, in my opinion.

[Dan L]

I am not a structural engineer, just an informed observer. It seems to me the problem here is that folks are trying to find ways to patch an old, very crude, Cub landing gear system to get better performance.

Most, if not all aircraft landing systems using shock absorbers perform their heaviest work in the compressed state, not the extended state, as found in bungee, AOSS or shock absorber fixes for the antique Cub landing gear design.

The result is these devices are seeing very high loads when nearly fully extended imparting significant moment arm bending on the associated structures. Given the restrictions associate with the old design of the Cub landing gear this is the only way to absorb the energy associated with landing loads. But it is not the best way, in my opinion.

I have always thought of the traditional Cub gear system as one of the best things that make a Cub a Cub. It is rugged, dependable and simple in a traditional manner. The gear, along with a trimmable stab, rounded wing tips, clam shell doors and tandem seating all come together to make an icon that is the best in its class. Cub Crafters has refined it even further but kept the basic elements the way they should be.

The Beringer gear may well be an even better system. I’ve looked at it at the Anchorage trade show a couple of times and was impressed with what I saw.

My opinion is that spring gear is a step in a different direction. One I don’t want to go down. Spring gear is fine on my Cessna but not my Cub.

[cityrancher]

For years I flew Cessna 185 and 180's on skis on the glaciers of Alaska. Among my fellow ski pilot friends there were many gear failures where the ski axle attaches to the Spring gear. Everyone knew the loads were high on this point and most dye penetrated their gear before and after changing the ski/wheel axles. Eventually an aftermarket titanium gear was available and most of the commercial guys changed over. It as VERY expensive and very restricted on any mods or God forbid holes. I would be willing to move to Spring gear for the additional airspeed but there are trade offs.

[Springloaded]

I have always thought of the traditional Cub gear system as one of the best things that make a Cub a Cub. It is rugged, dependable and simple in a traditional manner.

Absolutely Dan
BERINGER is new to the market I haven’t seen anyone running it on a cub except For there plane. I’m not saying it can’t handle it but time will tell when somebody puts it on there cub and actually abuses it. There is also a lot of dissimilar metals and lots of nuts and bolts and moving parts. How about when it gets side loaded with the gear leg that far down looks like a lot of leverage on the Cabanvee? I also think the fuselage was engineered for loads to be applied with the standard gear now we are going to put the load in a direction that it wasn’t Intend for. With the bar off the Cabanvee being solid the way I see it your changing how the load is applied.The material and quality of there parts look outstanding but to come to a conclusion it’s far superior at this point is a bit much. Clare actually sent me a complete set up for me to try out. I have my new 35s mounted on there new 10” wheels that will go on soon as my cub gets back. I’m excited to try them. I just wasn’t willing to put it on and head to AK on it. I was just as skeptical when Hodges approached me with the Acme. I have found when people get stuff like this it instantly turns into the best that’s out there. The gear in these cubs are very strong , time tested and the Acme Suspension makes it even better. I’ve put over 300hrs on there Suspension and I can tell you it works extremely well on rough terrain. The gen2s worked well but I had some complaints and working with Matt and Eric they have resolved all those issues and I’m not sure it can get much better then what I have. At some point it’s just to Damn rough to land a plane on. I actually had Matt the owner in the back up in Alaska when we landed on rocks bigger then soft balls, I was following a cub on 35s and didn’t realize how big they were, (I can tell you they don’t stack well) he was amazed we landed on rocks that big and the Suspension did its job well.
Chuck

[turbopilot]

I’m excited to try them.

Probably a good idea to try them before jumping to conclusions about the new gear. So far it appears I am the only one reporting experience with both gear types on this forum. Beringer ALG is clearly much better gear than standard AOSS enhanced gear. Anyway, I was not intending to draw a specific conclusions about the difference in gear types, just that the old Cub gear configuration was probably not designed with landing load impact absorption as a high priority. My only experience is flying the AOSS old style Cub gear and the Beringer gear. I have no experience with any other modifications of the existing Cub gear.

My point was that I cannot think of one automotive or aircraft application of a shock absorber designed specifically to handle maximum loads in the extended position. I think there is a very good reason for this. Could be wrong.