Balanced Tail Worth It?

Seeking opinions regarding a balanced tail on a stock O-235C PA-12. Is it worth the expense and effort? If so, is a PA-18 tail the only option or could one use the smaller PA-20/22 tail to help keep the EW down, while still profiting aerodynamically from the balanced affect...?

I am aware there presently is no STC for a 20/22 tail on the -12, but maybe some of the old school members have experience or knowledge with this combination from their 337 days...

Thank you

Jeff

For what reason are you interested?

The area of the tail is sized for the airplane. A smaller area (PA-20/22) unless someone has an STC, has not been tested. A smaller horizontal area could reduce pitch stability along with reducing a loaded CG range.

The difference between balanced and unbalanced would primarily be lighter control forces followed by increased elevator authority which likely would be more noticeable when landing at forward CG.

Another advantage would be lowering the nose during spins if it starts to go flat at an aft CG.

My opinion, no. I owned a Legend Cub that might have benefited from a balanced elevator. But not real annoying. I gave a guy his TW endorsement in his stock PA12. I flew it solo a couple of times too. Never once thought about wanting more elevator authority or lighter pitch control. Pretty much flew “right”

skywagon8a said:

For what reason are you interested?

The area of the tail is sized for the airplane. A smaller area (PA-20/22) unless someone has an STC, has not been tested. A smaller horizontal area could reduce pitch stability along with reducing a loaded CG range.

The difference between balanced and unbalanced would primarily be lighter control forces followed by increased elevator authority which likely would be more noticeable when landing at forward CG.

Another advantage would be lowering the nose during spins if it starts to go flat at an aft CG.

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The purpose is clearly to improve performance by way of the balanced feature in the tail. The PA-20/22 tail surface is the exact same surface area (not smaller) as is the PA-12 surface. Using the PA-18 tail (as is required) with an upgraded motor such as the 320 or 360 makes sense, given the added weight up front. Staying with a STOCK 235 however, there is no weight change up front - thus, using a 20/22 tail will help keep the empty weight as is, but add the improved pitch range due to a balanced (20/22) tail. Thats the question...

jeffh747 said:

...could one use the smaller PA-20/22 tail to help keep the EW down...?

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jeffh747 said:

..The PA-20/22 tail surface is the exact same surface area (not smaller) as is the PA-12 surface.....

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Is it smaller or not?

skywagon8a said:

Is it smaller or not?

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The PA-20/22 tail is smaller than the PA-18 tail which can/is often supplemented on the PA-12. The PA-20/22 tail is NOT smaller than the stock PA-12 tail.

Sorry, I need to be more clear with my wording to be sure they're loophole free...

OK in that case, since the pitch forces would be lighter an STC would likely be required. There is an Advisory Circular to determine whether a Field Approval or STC is appropriate. There may be a requirement to install balance springs such as on the early PA-18 drawings. Someone here can supply the drawing number. In addition to the lighter stick forces, the pitch control would be more powerful. The elevator would have more authority when operating at the extremes of the CG envelope.

I flew a -12 with an O-320 and stock tail one summer towing banners. I didn’t find it objectionable for normal flying, but it had a boom hitch mounted to the gear fittings. With a sign on it took full up trim, and dropping the sign was an exercise in release, power, push forward on stick, crank nose down trim as fast as you could!


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dgapilot, How about you explaining to jeffh747​ about the approval requirements for his request?

Envy energetic person with a lively mind wants to make things better. It is a great American tradition, and has served us well. However, a well rigged stock 12 flies nicely. The 20/22 tail is identical in total size, but increases the elevator area by replacing some of the stabilizer into the aerodynamic balance area of the elevator. They just change the shape to include the aerodynamic balance. You do actually reduce the size of the horizontal stabilizer area. It could (only could) reduce the effectiveness of the trim if you're a bit short of nose down - or more likely nose up. I've had every combination on every sort of J-3 ,PA-12, J-5 with every sort of engine, and a PA-20 with a 150. Chances are the difference could make It "less nice" or stay just the same. Don't waste your time. Also, the big tail PA-18 will shake more, leading to earlier wear on the jack screw etc etc. If it ain't broke, don't fix it. Buy gas and fly.

all correct and understood, especially the STC and paperwork part. I was however hoping to find someone who has experience with this setup as it has been done before with a 337. It's not a new idea. With all the STCs out there for the whole Cub series, I'm a bit surprised no one has taken it upon themselves to create one. I just may do so, but I'd like to hear from some who has first hand experience flying one.

Like Richgj3, I've owned an AL3 and with the right/wrong load, one can run out of authority (trim as well) in the low speed/low energy range ie flare - misjudge and you're hanging feet up with no more pull. There are comments in this forum about the same issue with a stock -12. Seems like it would be an easy fix with the right tail.

No sir - if we all followed the "if it ain't broke don't fix it" mentality, we wouldn't have advanced aviation over the last 100 years. Theres nothing wrong with improving on these old designs - especially if you're restoring one from ground up with the intention of giving its 70 year old life new energy for the next 70. The average pilot has increased in size since the 1940s as well ... least we not forget get that.

Again as I mentioned several times - I'm well aware of the approval process. I'm looking for some first hand flying experience with this setup.

If anyone has some, please let me know, otherwise thank you all for your input...

Jeff

skywagon8a said:

dgapilot, How about you explaining to jeffh747​ about the approval requirements for his request?

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Any changes to the movable control surfaces now needs to be done by STC, unless you have previously approved data (STC, pre October 1957 337). Someone else’s 337 as supporting documentation won’t get you a Field Approval any more.

Figure at least 2 years worth of work and possibly as much as 6 figures for cost. Would not be an easy project. There would be a fair amount of flight testing involved, all with a DER Flight Test Pilot. You would need to prove the structure for the change to flight loads resulting from the aerodynamic counterbalance, all substantiated by Structures DER reports. The cost of certification is one of the main reasons these types of alterations aren’t done very often. You would need to have a ready market for lots of airplanes to justify the expense. It’s hardly worth it for a one time STC. I’m doing a one time STC on my Clipper to increase gross weight, and I’m guessing that I’ll have over 300 hours of work in it before I’m done. And that’s just the paperwork side, not doing any of the alterations on the airplane to satisfy the structural changes necessary. Fortunately I’ve convinced FAA that I won’t need any flight testing for my project.

The J3, J5, PA-11, PA-12, PA-14?, PA-16, and PA-18-95all used the same tail feathers. The PA-20 and PA-22 tail feathers are the same area total, but as stated elsewhere in the thread have the counterbalance. PA-18-150 tail feathers have more area.


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I have experience flying the exact -12 tail mod you are contemplating, and while not terribly short on hours in it (probably a couple hundred), it is minuscule compared to the man who offered you the advice you rejected.... I think his suggestion to leave well enough alone was the 'cliff notes' version relating to this particular mod. His experience flying modified airplanes spans a lifetime ;-)

My personal opinion, may vary from others because I would not be looking at the equation from a 'working bird' view. The mod may not be enough of an improvement in some folks minds to be worthy, but if you're starting from a rebuild and have easy access to the tail feathers and a path of installation, it will certainly be noticeable in the balance and control pressure departments.

Side note for a parallel comparison; I have a pair of Thrush aircraft, same size, same engine. One has a fresh engine, fresh over all rebuild down to the paint. The other is pretty much timed out in every aspect, but it has a modded tail that doesn't change the hauling capabilities, it simply eases control pressures. A lot of other facets are affected as a result of that, but those are beyond the scope of your concerns here... Being a single pilot operation, I could pick either on any given night. Probably don't need to tell you which one I climb in almost every time ;-)

I like a good flying airplane. And I like a better flying airplane more!

This mod isn't new, finding 337's will not be hard. It has also been done to J3's, but there are plenty of 12's with that tail, both restricted and Std. You probably could never make developing an STC for this pencil out, as most people that are spending serious money on a 12 for mods will end up with the -18 tail.

Good luck!

Take care, Rob

Are the Atlee oversized ones STC for -12?


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Thank you for your input Rob.

As far as "rejecting" WM's advice, I didn't. I reject the, I've been there done that mentality. I have no clue what WM's experience is, but I'm sure its valuable - as any experience is. That said, nor I have not divulged my experience...

I had/have a fact based, reasoned based question, seeking the same in form of first hand experienced opinions such as yours - again, thank you. An adage such as ...if it ain't broke, don't... spewed down from on high, steams me to no end. It runs contrary to the natural, ever questioning minds that truly do aviation justice. I have had the honor of working, developing and flying with some very impressive professionals over the course of my career and one thing I've learned, is to never underestimate a peer's experienced, as well as to never be condescending mine!

jeffh747 said:

Seeking opinions regarding a balanced tail on a stock O-235C PA-12. Is it worth the expense and effort? If so, is a PA-18 tail the only option or could one use the smaller PA-20/22 tail to help keep the EW down, while still profiting aerodynamically from the balanced affect...?

I am aware there presently is no STC for a 20/22 tail on the -12, but maybe some of the old school members have experience or knowledge with this combination from their 337 days...

Thank you

Jeff

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Have you flown it yet with the stock tail? I have friend with a -12 unbalanced elevator and it flys very nice, I had one and wouldnt change it. Set the stab where it needs to be with trim and fly and enjoy it. Trimmed right flys hands off

Supertwotwo said:

Have you flown it yet with the stock tail? I have friend with a -12 unbalanced elevator and it flys very nice, I had one and wouldnt change it. Set the stab where it needs to be with trim and fly and enjoy it. Trimmed right flys hands off

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I have but many years ago. It sounds like my answer is to stay with the stock tail. Thanks

I don't think anyone is speaking up against improvement, innovation is great--
but there is a matter of cost vs benefit.
I believe DGA Pilot when he says probably 2 years & 6 figures to get an STC for this relatively simple mod.

I recently got a field approval to put 26" GY's on my 180,
a simple & pretty common mod that surprisingly no one has ever gotten STC'd.
It tool almost a year to get this FA from our inspector at the Seattle FSDO.
Another guy that my IA knows wants to do the same thing--
he talked to a different inspector at the same FSDO & was told
"no way-- maybe in Alaska but not here".

Another friend is in the process of getting an airworthiness certificate for a foreign warbird,
it is proving to be a frustrating paper chase for him.
Getting the airplane itself squared away was the easy part.

I owned this airplane for several years. 100 hp and a PA-18 tail. There is no downside to a big tail on a stock PA-12

From the Cub Club magazine 1984. PA 20/22 tail surfaces no STC needed.

There you go - thank you for this info and your PM!

I have no doubt the balance tail is a performance enhancer. The PA-18 tail on the larger engines makes sense. I’m currently running the calculation on the PA20/22 tail with a stock -12 and am sure the results will be encouraging.

Even if it ain’t broke you can still make it better.

apologies to all the forum gurus and your loyal followers

Adding a balanced PA-18 tail to my PA-11 was both a good and a hmmmmm. Flaps required it. I felt the elevator response was more linear with the larger tail vs requiring increased effort with more deflection with the original. But it adds weight which can affect W&B. The PA-20/22 might be a good compromise.

I flew a stock PA-12-150 with original tail and my PA-12-180 with PA-18 parts close in time. I could get away with little trim change with the balanced parts during landing. The stock tail (and I) seemed to need more help from the stabilizer.

Gary

I have flown and worked on 12's with stock, 20, and 18 tails. For whatever reason, the one with the 20 tail flew the best. This is just a feel thing.. take it for what it is worth.

BC12D-4-85 said:

Adding a balanced PA-18 tail to my PA-11 was both a good and a hmmmmm. Flaps required it. I felt the elevator response was more linear with the larger tail vs requiring increased effort with more deflection with the original. But it adds weight which can affect W&B. The PA-20/22 might be a good compromise.

I flew a stock PA-12-150 with original tail and my PA-12-180 with PA-18 parts close in time. I could get away with little trim change with the balanced parts during landing. The stock tail (and I) seemed to need more help from the stabilizer.

Gary

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that seems to align with my original thoughts. Thank you for your reply!

Jeff

cruiser said:

From the Cub Club magazine 1984. PA 20/22 tail surfaces no STC needed.

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I wouldn’t take that to the bank. A lot of policy has changed since 1984!


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The Donald Snyder 150 hp STC that cruiser posted is what I used and used the original tail. I flew it quite a few hours by myself and it worked but I'm no expert. I saw a Donald Snyder post on the PA12 facebook page a few days ago and asked if he is the same person but no response.

I just checked FB and Don did reply and here they are--------I was selling stc also had many pa 12 that I converted . My favorite aircraft is a PA12 PA 22 tail feathers are same area as original pa12 but with balance area takes pressure off of stick when landing. and PA18 tail feathers have more area and will give you a little more control at slower speeds needed area on pa18 s with flaps

Pa22 tail feathers can be done with a 337 not a big deal reduces stick forces easier to get the tail up.