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PA12 Flight Characteristics Vs. PA18

Steve Pierce

BENEFACTOR
Graham, TX
I fly my Super Cub several times a week and have recently flown several Super Cruisers. 2 were 180 hp and the other 160 hp with the long mount. Trying to figure out if I am biased, curious what others who have flown both think comparing the two. I am aware of the physical differences but would like to hear other's experience flying both airplanes.
 
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Steve, owning one thing over another normally makes one at least a bit biased - it's a perfectly natural, or at least perfectly common thing.

I have not flown a 12 in over ten years, and the last one I flew was not a prime example.

Of course, we are all waiting for Wendy to chime in here... :)

sj
 
Steve
I have Marks PA- 12 in my hangar and get to fly it on a regular basis along with my cub. And occasionally other super Cubs. Marks 12 has very few modifications other than 150 hp and super cub tailfeathers so it is very light. The PA 12 requires a lot of trim. If you are 10 or even 5 miles an hour off of your trimed airspeed the stick becomes heavy very very quickly so one significant difference between the 12 And the 18 is that the 12 requires a constant, and significant, amount of trim.
Perhaps because of the angle of incidence the 12 does not take off anywhere near as short as the 18. I will take off from an intersection, even on amphibs, in the 18 that I would not consider doing in the PA 12 It just has a much much longer take off roll. Marks PA 12 does not have flaps and the 12 has a cleaner air frame than the 18 so it will float forever in the flare, and it is much more difficult to get slowed down on final. So making a short landing in the 12 is much more challenging than making a short landing in the 18. The only way to get in really short on the 12 without the flaps, is to come in completely crossed controlled, in a forward slip, to try to get behind the power curve a little bit so that you don't float in the flair. Some people have said that the PA 12 has a faster roll rate than the 18, but I don't see that. A significant difference is that you get into the PA 12 standing up, you get into the 18 sitting down.

These are just my thoughts, your mileage may vary, and I'm sure others will have another opinions as well.

Hope this helps



Bill
 
Steve, owning one thing over another normally makes one at least a bit biased - it's a perfectly natural, or at least perfectly common thing.

I have not flown a 12 in over ten years, and the last one I flew was not a prime example.

Of course, we are all waiting for Wendy to chime in here... :)

sj


.....just like a PA-18, only better.......
 
The -12 I owned was pretty stock other than a short mount O-320. It was somewhat of an outlier as it had the original unbalanced tailfeathers as allowed by the Stoddard 150hp conversion (I think). Like Bill said, it was pretty nose heavy and you’d run out of nose up trim when slow and nothing in the back seat. It definitely would have benefited from a lighter prop (catto) and -18 tailfeathers. It was pretty stable in cruise, a little faster and had lots of aileron. More aileron than my -18 which I miss. Some have said there’s not much difference in roll between the two but I disagree. I never felt like I couldn’t pick a wing up in the -12 with just aileron alone. In my -18, I sometimes feel like I ask it to pick the wing up then it just gives me the middle finger so I stomp on the rudder. My -18 does have the early torque tube which Pierce tells me is heavier in control forces. My old -12 was 150ft longer on take off and landing with 31”s an 82/41 Borer and less hp than my 160 -18. For playing around, my -18 more fun.
........to be honest, I told my wife that I bought -12 because of the wide backseat and when her ass got big she’d still fit. She promised me that would never happen so I bought a super cub;-)
 
The two pireps here both use what I'd characterize as "partially" modified -12s. The pirep comments are no surprise. The perspective I'd like to hear would come from Steve P, about the differences between the three modified -12s he's flown. My old -12 was/is a sweetheart to fly. Take the flaps or -18 tail feathers off of it and it'll be less of a sweetheart. Comparing -18s to each other reveals different characteristics. I think the variation between modified -12s is bigger.

Did Airframes ever receive the STC for the 3-place Supercub airframe? 15 years ago I had a -12 project and an -18 project laying on my floor. I built the -12. Had a 3-place Supercub mod been available then? I would have built a 3-place Supercub. Funny, the best performing -12 I know has Supercub wings on it. I considered building an exp Supercub using -12 wings. That would be a fun project. But there are just too many fun projects and not enough time. Or Money!
 
I've owned and operated several PA-12's from 108 to 180HP. And PA-18's from 135 to 180. The Cruiser is just that - faster but not quite as good in slow flight. As always, weight is everything. Every single airplane is an individual with its own charms and flaws. PA-12's are heavy on trim, The last one I owned had the PA-18 elevator cable conversion and it made the stick extra heavy because the geometry made the movement greater per amount of stick movement. I didn't care for that at all. Just the same, if you have a nice Super Cruiser, it is a lot of bang for the buck; and a stock 12 with a good O-235 flies like a dream. As for ailerons, there is no comparison. The 12 with its frieze type ailerons is much quicker on the roll. Totally different aileron configuration. Steve P will remember my yellow 12/180 - with extra long wings and how responsive the ailerons were even then. It's kinda like, choose your preference.. light ailerons or light elevators. Or get a light Cubsky and both are "pretty good."
 
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I've never flown a 12. But I've flown alongside Wendy in her's and I can say that you'll want to be at the top of your game in an -18 to follow her around.

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I never touch the trim in my -12, except to accommodate changes in loading. O320, short mount, -18 tailfeathers, -18 flaps. No problem flaring.
 
Got to agree with Spinner2---Wendy really has the touch with her "12" I personally was spoiled from the beginning---First solo and 20 years in a friends 1952 PA-18 with no electrics and the 0-320 -150. Still my all time favorite. My budget would not permit the 18 so had 15 good years in a 150 "12" with flaps. Fifteen really good years. Light weight is what makes airplanes fly nice. Thought my 12 ailerons were the smoothest ever. Sort of a ham fisted old geezer but always thought the 18 the most fun but sure would not walk away from a good , light 12---FUN ---FUN ---geezer Dan
 
I have very little experience in rag wing Pipers other than J-3/PA-18. Definitely not qualified to comment.

When has that ever stopped me? I have flown Gordon's 12 - it flies like a Super Cub. Well set-up. I have flown a stock 115 12 a bit, and consider it a Piglet. It does cruise around 100 or so, but I would rather have a Citabria any day in the week. Also flew an otherwise stock 12 with 150 hp. Unimpressed.

I always looked down my nose at Pacers, but flew Don Lee's 160 Pacer on skis, and wound up impressed. Maybe it was the cold weather, but it performed!

In short, a good 160 Citabria would be better and cheaper than a restored 12, unless you really need to carry three cramped people at 100 mph.
 
I’ve flown my 12 with & without flaps, short mount, long mount, 108, 150 & 180 hp engines. Without flaps & with either long or short mount, it was trim trim trim, all the time. With flaps & short mount, I trim it once when the load changes & that’s it. Steve Pierce says my ailerons are heavy, but I guess I’m used to it & don’t notice that. At New Holstein & with the 180 hp, my 12’s take off & landing distances were right in the middle of all the stock 18’s (150-180 hp).
.....my PA-12 is like a supercub, only BETTER!!! ;)


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I had two PA-18-150's and a PA-12-180. The -12 already had extended wings, stock ailerons and -18 flaps, balanced and enlarged tail, 60 gal fuel, Crosswinds 180 STC and STOL kit, long -18 gear (don't ask how long), and at first an 82" constant speed prop. Plus the usual baggage mods and Cessna 180 front seat on rails. Weighed over 1300 but we complied with the STC and installed a fixed pitch 82-43 prop and other stuff got removed which got the weight down to the mid-1200's. It was an odd duck to fly compared to the -18's and really should be evaluated on their own as modified versus stock configuration. Never flew a stock -12 so can't compare. Electric trim would be nice.

It was a great floatplane but had the rudder centering spring STC which was not effective. Despite a short forward extension to the vert stabilizer (like Cessna's) it wandered about on its own and needed constant control input. I had the STOL cuff and fence removed and preferred that configuration which gained 10+ mph in cruise (yes the cuff was not drooped below the wing bottom). Stall with the cuff was quick when it finally let go, but mushier with the stock wing.

I'd not extend the wing and maybe that would help with the lack of longitudinal stability. Long gear is an asset as the -12 gear sits forward on the fuselage (or is just different in angle, not sure but have a look) and that plus the wing incidence gives a potential lower AOA than the -18. Power is nice and needs adequate fuel capacity with the 180 conversion.

For a float plane mission they are very nice. If wanted for rough and tumble rocks or skis I prefer the -18 which for me were lighter on the controls and lighter on the gear.

Gary
 
The biggest issue with a lot of re-powered 12's is CG. They are nose heavy and require constant trimming, and run out of elevator before the wing's done flying. The other problem is that with modding they can get fat in a hurry if you're not careful. A carefully modded 12 with a 150/160 and proper CG is a delight to fly. If the solo cruise trim has the H.stab more than 60-65% down the screw, you need to get the CG aft. I cheated a bit and put a ballast weight in the tail of about 5 lbs, and my empty CG is 14.59. I've considered going to a short mount and losing the ballast. It would probably lighten up the pitch some, but I really like being able to work on the back of the engine (pulling mags etc.) without having to strip the nose and swing the mount. Based on that, and the cost, I'm probably going to leave it as-is. Like Gordon, I only re-trim for changes in load. It flys great and will touch down slightly tail first at cruise trim/solo/full flap/no power. If I really want to drag it in, I give it 5 turns up trim and can touch the tail with the mains about 10-12" off. As I've said before, to build the 12 into a good bush machine, you have to love the airplane and hate your savings account.
As to the ailerons, they are slightly more responsive with a slight increase in stick pressure to go along with it, but neither difference is significant.
 
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Windy: Just curious---How many hours have you flown your 12---in all its many configurations ????? Seems every photo that Bill and his wife have posted (there are many at many locations) there in the foreground OR background sits your 12:smile:
 
In the last 12 Years:
O-235 engine = 350 hrs
O-320 engine = 800 hrs
O-360 engine = 1600 hrs
Ask me tomorrow & it will be more!


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Aileron response is much better than an 18. Flying a Cub is put all the stick in and then take out what you don't need. Yeah they are somewhat faster than a Cub, certainly fit more inside. But with all my time and bias toward the 12, the 18 in slow flight, t/o and flare is simply better. I can feel my dad's Cub all the way to the tie down. My 12 seems to lose feel and sorta drops to the ground at landing.
 
I purchased a 12 this summer which is a modded like an 18 with Kenmore conversion 150 hp, I have to say I really like the wider cabin room. It does need more trimming and won't takeoff and land quite as short as an 18 but it is close, recently put on top flap gap seals which helped with the flare and takeoff. It's a joy to fly as is the 18.
 
In 3 1/2 years I’ve got 750 hrs in a -12-180 ext wings flaps 3” -18 gear 31”, -18 tail When I first bought it the Cg was forward and nose heavy, landed in heavy snow and over on its back. Rebuilt and changed CG to 13.54” Empty weight is 1320#. Now I don’t need to retrim all the time and the controls are I would call even. Lands short and takes off short. Took 3rd at Skwentna in 2016. It is all about the CG with the big motor. Fun plane now that CG is correct.as the nose doesn’t fall out at landing. Compared to a J3 the controls are heavy but I’m use to them I guess. Comfortable, roomy, easy in n out with -18 front seat that slides. Cruise 2350 105 mph at 8.5 gph

Doug
 
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My point in owning a PA-12-180 (and I assume for others) was the ability to carry more baggage and possibly more weight than an upgross PA-18 (http://www.supercub.org/forum/showthread.php?21666-PA-12-Gross-Weight-Increase). It will do that to a point pending useful load.

They are not a PA-18 flown light nor should they be judged as one. Fly them for their great value and performance and forget comparing them to a PA-18 that's lighter and has AOA benefits. Two different tools for different jobs.

Gary
 
I found the 150hp/short mount/flaps/18 tail-PA12 to be comparable to the 160hp 18 in landing distance. The 12 would stay on the ground for 100-150' longer on takeoff. Cruise speeds were the same with 18 gear.
 
In 3 1/2 years I’ve got 750 hrs in a -12-180 ext wings flaps 3” -18 gear 31”, -18 tail When I first bought it the Cg was forward and nose heavy, landed in heavy snow and over on its back. Rebuilt and changed CG to 13.54” Empty weight is 1320#. Now I don’t need to retrim all the time and the controls are I would call even. Lands short and takes off short. Took 3rd at Skwentna in 2016. It is all about the CG with the big motor. Fun plane now that CG is correct.as the nose doesn’t fall out at landing. Compared to a J3 the controls are heavy but I’m use to them I guess. Comfortable, roomy, easy in n out with -18 front seat that slides. Cruise 2350 105 mph at 8.5 gph

Doug


Hey Doug, what did you do in the rebuild that affected/changed the CG?
 
MT12
I found that I needed about 9# added to the tail section to get 13.54" Then when I fly alone I put my tie downs, and tool bag in the extended baggage, about 25# to move it back about another 1" or so in the envelope. I can now get on the brakes hard and not worry about the tail coming up. This makes it so I do very little if no trim adjustment as I go thru the flap settings and the trim is about 1/3 up from nose up. If I add a 180# passenger I do about 3-4 turns nose down for take off. Very well balanced, on the trip to AK when really filled up with gear and one passenger I needed to add another 3-4 turns nose down, so now the trim is centered if not a little forward of center on the trim indicator, take off run would be 600' at sea level or close to it. It is all in the setup and any of the -12 that are nose heavy are not set up right, this is from feeling it before and then understanding what I needed to do to put the empty and flying CG in the right spot. Just make sure the weight is solidly attached so there is no movement.
My strip at home is 800' and I generally touch down and stop in under 500' with ease, not having to get on the brakes hard to stop. If I really need to stop it is in 300' if not shorter with no wind.
If you are running out of nose up trim when landing light with flaps lowered you need to move the CG back. IMHO

Doug
 
There are so many variables---empty weight---rigging----etc---etc. Pilot skills and FEEL for his/her airplane. Have flown a number of Super Cubs that are "supposedly" stock---and seldom find any two that fly the same. Piper had some "variables" in there building process also. Just part of what keeps it all so interesting:???:
 
I'm a little late to the thread, but I figured I'd throw in my 0.02 american. I've flown a few PA-18s, and a few PA-12s, all of which were in various stages of modification (or not). I found that the less-modified PA-12s generally flew "nicer" than the highly modified ones. A friend has a stock PA-12 with but one mod - Tri-Pacer elevators. It's light, rigged right, and a joy to fly. No more trimming needed than any Super Cub, and the ailerons on a -12 are SO nice!! Super Cruisers with bigger engines and other mods may perform better overall, but they don't fly as nicely in my mind. Same with Super Cubs. I can't find one that flies nicer than my stock 90 hp PA-18. Sure, others will out-perform me in some missions, but I haven't found one that flies nicer.

Now, as someone said, there are too many variables and too much subjectiveness (is that as word?) in this type of discussion to be able to come up with any concrete answers. But for what it's worth, those are my thoughts. As always YMMV!
 
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