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TK1 vs. Acme Aero (SEP 2020)

Cubs have very tough gear already. The modern shocks let us get away with even more. Its likely that CC accidents and incidents would be more frequent and worse with bungees. I think my TK1 incident would have been worse. And Pierce is right a bounce sets up a directional control issue. Search "How to set up a groundloop" by Bill Rusk.

Carbon Cubs have something in common with the "doctor killer" Bonanza. Anything really unsafe about the aircraft? The statistics are showing more about the judgement and proficiency of those buying and flying than about the design.

You are gonna love that FX3 with Acmes.[emoji16] If you want to love it even more, go try a stock Cub with bungees.

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Cubs have very tough gear already. The modern shocks let us get away with even more. Its likely that CC accidents and incidents would be more frequent and worse with bungees. I think my TK1 incident would have been worse. And Pierce is right a bounce sets up a directional control issue. Search "How to set up a groundloop" by Bill Rusk.

Carbon Cubs have something in common with the "doctor killer" Bonanza. Anything really unsafe about the aircraft? The statistics are showing more about the judgement and proficiency of those buying and flying than about the design.

You are gonna love that FX3 with Acmes.[emoji16] If you want to love it even more, go try a stock Cub with bungees.

Thank you, much appreciated. When buying your first plane and you see a bunch of accidents you too will over analyze. Not ashamed, I'd rather learn and be safe and learn from others.

I have considered, and still am considering holding off on the Acme's so I can fly maybe the first 20 hours of the EAB fly off on bunjees then have TacAero install Acme's so I can appreciate them. My TW endorsement was in a sport cub on bunjees, I'm not sure why my instructor didn't triple the number of landings logged as I'm sure it was three per stop and go :) Having flown the sport cub on bunjees I'm not afraid of them, it was a good learning experience. I'm looking forward to acme's but it won't take away from the landing effort required to do it right.
 
View attachment 51575Confucius say....learn to putt with the putter ya got!
Go all over , See some Purty rough stuff ...Redneck + TK’s for rebound only works really good! $800.00

How long of a stroke are those shocks? I've been kicking around the idea of rebound-only shocks. Those look close to what I've been imagining.
 
Yep I did over analyze too. It can be hard to sift through the internet static and get good info.

You are gonna love those Acmes!!!

BTW here is what my version of stupid looks like....not bad design. This impact bent all the bolts in the landing gear system. The safety cables caught it. I doubt you will duplicate this level of dumb but saftey ropes from Airframes are pretty cheap/light insurance off airport.Screenshot_20201011-211433_Gallery.jpeg

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I have personally watched two CC (one SS and one fx3) wreck in the back country here. Also observed a CC specific flyin a few years ago where they wrecked three in two days. Not one related in any way to the landing gear (brakes were an issue on two of them). Every one was pilot induced. Tom
 
John Roberts of AvWeld in Idaho made my gear for my S-7S. He claims to be the first to come up with the concept of arranging the shock struts so that the shock works in compression, not tension. Mine uses bungees to take the impact, exactly like an old style Cub gear, but the Fox air adjustable shock controls the rebound. It works great, and I wouldn't change a thing, coming up on 2000 hours since I installed it.
 
...He claims to be the first to come up with the concept of arranging the shock struts so that the shock works in compression, not tension. ... shock controls the rebound. ..

thats the NORMAL supercub Bungie setup that been around for?? 70 years?? just not adjustable...

that every one replaces with better solutions...
 
Can anyone articulate what is better about the Acme offerings compared with the AOSS that CC offers as a factory option on the FX(on their website form)? Do they put Acmes on FX builds for an additional charge? I have broken a spring gear on a cessna :D on some rocks so I am concerned (luckily the plane was so old, the gear leg must've been rusted in place enough for me to limp home on a sheared bolt after I rejected the landing).
 
thats the NORMAL supercub Bungie setup that been around for?? 70 years?? just not adjustable...

that every one replaces with better solutions...

I may have explained it backasswards, wish I could find the picture I took of the insides. It is not like the stock cub setup, other then the bungees and how they work, there is an extra strut in there that the air shock mounts to. The one thing I know is it works great, it was a $1800.00 upgrade over the bungees only I had before. All nicely faired too.
 
I just fly them, I don't know all the why's and wherefores! But now that I think about it.....I have the reliabilty (??) of the known "technology" of bungees, without their springback/relaunch tendencies. A conservative approach, not trusting the whole shock only thing I guess? 12 years old now, back before the tech of aircraft shocks was advanced as it is now. If I wiped it out tomorrow, I'd go straight Acme or TK's. But either way, I'd have to fair them, they both look pretty draggy.
 
Can anyone articulate what is better about the Acme offerings compared with the AOSS that CC offers as a factory option on the FX(on their website form)? Do they put Acmes on FX builds for an additional charge? I have broken a spring gear on a cessna :D on some rocks so I am concerned (luckily the plane was so old, the gear leg must've been rusted in place enough for me to limp home on a sheared bolt after I rejected the landing).
It is my understanding that the engineers at Cub Crafters have tested and approved the Acmes on the FX series and it is now a factory installed option. There is an opinion piece written by two high time FX pilots who gave PIREPs on flying all the different options. I know burl at AOSS is sitting on several sets that Cub Crafters wanted but have now cancelled. AOSS is simple and is a polymer and really no maintenance. The Acmes need to be checked by hoisting the aircraft with weight off the shock and checked with a good gauge that will not let any pressure out and serviced with nitrogen using that gauge and fill valve.

http://forum.cubcrafters.com/showth...es-AOSS-TK1-and-Acme-quot-Black-Ops-quot-Gen3

https://www.supercub.org/forum/showthread.php?53414-Suspension-Test
 
To the unknowing, Acmes and TK1s are best charged to desired gas pressure which no weight on the shocks. It isn't difficult to do it with the plane on the ground but it isn't as accurate. Better said the shocks are less sensitive to changing length with added pressure, but that's easy to deal with. Pressurize, roll the airplane around to normalize the shock
Length, repeat if necessary. If I have 180# of pressure in my shocks and one leaks down to 160# (it's never happened) it would be very easy to recognize. If it did happen I'd send the shocks to TK for servicing. The truth for these shocks is we set em and forget em. They're very low maintenance.
 
I've had bungees, AOSS and Acme's all on the same plane. The OP asked about application on an FX3, my experience with these is on an EX, so very comparable. In my opinion the most noticeable improvement was going from bungees to AOSS. A very big step up. AOSS stay glued to the ground in most situations. The Acme's are better yet but the AOSS are good enough that the difference is not as great.

I would not consider ordering a new FX with bungees. You'll soon switch to one of the better systems and then be trying to sell your bungees at a big discount.

No Experience with TK1's. But I did recently put a T3 tail spring system on and that's a big, big step forward too over the Pawnee spring I had. And I'm a wheel-landing guy 99% of the time.
 
This thread has been a fun exercise with lots of info hidden within it. I’m not trying to be a smarta$$ but why doesn’t the OP just buy a set of each. Run each model for 25hrs then sell the least favorite one? Yes it’s real money but each system costs roughly 1% of the all in price of the FX3. Big picture, that’s not much. Then, maybe you take a $500 haircut on the 25 hr used shock system you don’t like as well AND you get to be the guy that can actually testify to running both on your cub giving the pros and cons of each
 
This thread has been a fun exercise with lots of info hidden within it. I’m not trying to be a smarta$$ but why doesn’t the OP just buy a set of each. Run each model for 25hrs then sell the least favorite one? Yes it’s real money but each system costs roughly 1% of the all in price of the FX3. Big picture, that’s not much. Then, maybe you take a $500 haircut on the 25 hr used shock system you don’t like as well AND you get to be the guy that can actually testify to running both on your cub giving the pros and cons of each

You mean run one on each side? Ha Ha. That would give you a side by side experience. The joys of EXP i guess
 
I will have the opportunity to try each, actually 3. I have FX3 training in Jan so I'll experience the Acme Pro's on that plane. As of now I've changed my mind and do not feel comfortable going with Acme's for multiple reasons. I don't think the design is sturdy enough, the history of failures, and the email exchanges I've had with the company inquiring about the FX3 accidents. This morning I googled "acme aero shock failures" and found another incident resulting in $55K in damage to the plane. I don't have all of the details but you can read the thread:

https://bit.ly/2GTt5wA

I've been pleased in my communications with Tony regarding TK1's and have read and viewed many great reviews on the TK1's. I feel more comfortable with this design underneath my $330K airplane. I will order the plane with stock gear (bunjees) and have TK1's installed after delivery therefore allowing me to fly all 3 gear systems at some point in this process.

In post #72 above by Steve Pierce, the 2nd link about 3rd post from the end raises a valid point. Follow the money, those that are doing testing or pushing a product potentially have a financial gain from it. Know who the dealers are when getting recommendations.

Moral is based on what I've seen in the past few weeks and been exposed to from various people and companies, I would never feel at ease with Acme's on my plane. That is my personal feeling and what I choose is something I have to have confidence in. This could change but as of now, it's no go for Acme's for me.
 
That's as good an answer as any and more honest than most. It's your plane. Do what makes you happy. You're living a lot of guys' dream.

I'm a TK-1 fan. Good products. Great support. I can't imagine you'll be disappointed.
 

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I'll probably get laughed at for even asking about this - but an FX3 is a pretty fast cub. I am reading that the AOSS has the ability to wear bungee fairings for a gain of 1-2 mph (at the cost of a few pounds of weight, I guess). Is that even a valid consideration? If you're going to spend the money on a 186 HP motor and constant speed prop, might as well get every last mph. How about fairing for the Acme and TK-1? I'm guessing it wouldn't make sense due to the necessity of servicing the nitrogen charges. Probably silly to ask, but nothing else to think about while I'm in quarantine.
 
I have read talk of fairings over the TK1's. It is added drag for sure. I'm just not sure how much I care about speed. I'd certainly be interested in making it aerodynamic but also protect it from the elements, exhaust, etc. but not if there is risk of something flying off and hitting the tail.
 
If you want speed I would do a fairing in a heartbeat. One reason to get any of this advanced gear is for rough off field work. Rocks/sticks/brush/whatever is going to be a much bigger threat to your tail than a well made fairing. The other reason is to help hide all you bad landing habits. In either case a well made fairing is not an issue with safety.
DENNYT
 
I fair every thing I can, not for speed but less drag. Screw speed, but better range/ less fuel burn, better climb and glide, all result from less drag. Good attributes in a back country plane I'm thinking, and I hate to throw them away in drag I can get rid of. Small amount? Sure, but there nontheless. I also drive the first or second lowest drag car on the planet!
 
FYI, the link to the super stol discussion of shock failure brought up an almost five year old thread. I wouldn't base a decision on such outdated information, especially with a continually evolving product.
 
I will have the opportunity to try each, actually 3. I have FX3 training in Jan so I'll experience the Acme Pro's on that plane. As of now I've changed my mind and do not feel comfortable going with Acme's for multiple reasons. I don't think the design is sturdy enough, the history of failures, and the email exchanges I've had with the company inquiring about the FX3 accidents. This morning I googled "acme aero shock failures" and found another incident resulting in $55K in damage to the plane. I don't have all of the details but you can read the thread:

https://bit.ly/2GTt5wA

I've been pleased in my communications with Tony regarding TK1's and have read and viewed many great reviews on the TK1's. I feel more comfortable with this design underneath my $330K airplane. I will order the plane with stock gear (bunjees) and have TK1's installed after delivery therefore allowing me to fly all 3 gear systems at some point in this process.

In post #72 above by Steve Pierce, the 2nd link about 3rd post from the end raises a valid point. Follow the money, those that are doing testing or pushing a product potentially have a financial gain from it. Know who the dealers are when getting recommendations.

Moral is based on what I've seen in the past few weeks and been exposed to from various people and companies, I would never feel at ease with Acme's on my plane. That is my personal feeling and what I choose is something I have to have confidence in. This could change but as of now, it's no go for Acme's for me.[/


Hawgdrvr,

It is unfair to ask a manufacturer directly about a product failure they’ve had on a customers plane.
Talk about putting them on the spot- how to answer? Do you expect them to say, “yep our Shocks failed, buy them somewhere else”? Or, because likely there have been no witnesses, or credible ones, do you expect them to say, “yep the pilot didn’t know what he was doing and rammed the plane into a place it should never have been and something had to give”? That could be the case, but, any business person in the small aviation community, is going to be a bit careful on what they say. They may think it, but won’t say it - who wants to make their customer look bad? Even if they did screw up.
I’m not buying your story. Not at all. I know this company and their product well. Your research doesn’t add up. You have a problem with the company and you haven’t even owned a set. Based on google(??). Not cool man.
RoddyM
 
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I've had bungees, AOSS and Acme's all on the same plane. The OP asked about application on an FX3, my experience with these is on an EX, so very comparable. In my opinion the most noticeable improvement was going from bungees to AOSS. A very big step up. AOSS stay glued to the ground in most situations. The Acme's are better yet but the AOSS are good enough that the difference is not as great.

I would not consider ordering a new FX with bungees. You'll soon switch to one of the better systems and then be trying to sell your bungees at a big discount.

No Experience with TK1's. But I did recently put a T3 tail spring system on and that's a big, big step forward too over the Pawnee spring I had. And I'm a wheel-landing guy 99% of the time.


so what number bungees did you have and whats the empty weight of your plane, every one groups all the bungees into bungees and most dont know the difference.
 
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Yep, them Acme's are weak, ask Tony, he'll tell ya. 8)
 

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In post #72 above by Steve Pierce, the 2nd link about 3rd post from the end raises a valid point. Follow the money, those that are doing testing or pushing a product potentially have a financial gain from it. Know who the dealers are when getting recommendations.
He is actually a Cub Crafters dealer. there is a reason he recommends the Acme shocks, he believes in them. I am a dealer for Univair, Airframes/Bushwheel, Trig, Uavionix, Electronics International, JPI. I recommend the products I have good service out of both the product and customer service. I can make money on any of them but I also have my own reputation and head aches down the road to deal with if I recommend something that is not up to snuff. You have made up your mind what you want and why but I am not buying accidents from 2015 on a Highlander and the fact that one of the test pilot's happens to sell Acme stuff. If you haven't figured it out yet it is a small world here and most everybody knows one another. Usually no bullshit. I think there is some great information on here on all 4 options and all are fine and have proven themselves. Some are a nice leap in technology that is ever evolving like the extended stroke Gen4 I saw at ArkanSTOL.

As far as streamlining I see it as what ever you mission is. Certainly won't hurt anything. Piper streamlined the bungees and it helps. Acmes will be easier to streamline than TK1 for sure as are the AOSS. It's your airplane, set it up for you and your mission, if someone doesn't like it they can do theirs how they see fit.
 
Let me circle back to the beginning here in why I've asked questions along this line and another thread prior to this, I think it was about Beringer. A friend knowing I have a FX3 on order decided to research FX3 accidents and then SS accidents. There was a common thread to the FX3 accidents, gear failures but yes, it could have been pilot induced. I agree, accidents from years ago are older generation products and hopefully and certainly products have improved since. But the trend in the research drew concern and caused me to make a decision on what I should do with my FX3 hence this thread and the other learning about the landing gear options.

A few questions up, let me put this in another scenario: I'm building an experimental aircraft and I have a few choices in engines. If I learn there are 5 engine failures but in an engine that seems to be highly recommended, you bet I'm going to do research, ask questions, see what the company has to say about the incidents. Are we beyond this? Is it corrected? What was or is the corrective action?

Am I going to make a decision based on what the small community says to use and go blindly with that? Or do my homework and make my best educated decision. It's a heck of a lot of money for a repair so this decision is vital. It may not make everyone happy but we all have to choose. You may like brand X and someone else brand Y. Nothing wrong with discussing and educating in a positive friendly manner.

I've gone through a lot of time and research with the help of many here to vet the options. I made my decision, I'm hoping for the best for myself and others with these choices to avoid financially devastating situations. I also like to see when a company steps up to help when there is a problem, I didn't find much of that in this research other then replacement of failed products.

I'm used to trusting my maintenance unit and crew chief. Now that is all ME. That's scary! Decisions are critical.

By the way, I have an outstanding salesman from CubCrafters and I trust in his recommendations. I believe Acme is the best option of what CubCrafters has to offer. I wish they also offered TK1's but they don't.
 
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2 thoughts.

When you ground loop that new plane at 10 hours or flip it it won’t really matter all this research you did.... happens allot with new guys. (Happens with experienced guys to, nothing like repairing a 10 hour old rebuild because of pilot error) Buy good insurance... can you actually get full value insurance??? I had heard max of 250k$ on experimental???

Fairing the Tks was discussed previously by dan default, didn’t work well. Not sure if he ever got it figured out??


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