I wonder why piper chose usa 35b airfoil?? Clearly there are better foils out there for the application. I believe there would be less stall spin accidents if they had chosen a different airfoil. There are foils that do not require washout due to the soft stall characteristics, the cub airfoil has a nasty power on stall. Washout is a fix for a poor airfoil characteristic in my book. From the research i have done there was not much data done back then and thus the choice of the usa35b, and why do many companies use variants of the airfoil is this a case of monkey see monkey doo???? I know there is alot of cub purists out there and dont mean to upset any of them but i cant help but to think these planes would perform and be safer with a different air foil. Any input from anbody would be appreciated.
Why USA 35B????
- Thread starter gander
- Start date
King Brown
Registered User
Nova Scotia
Why US35B
I'm no purist and slave to orthodoxy and know nothing of comparative advantages of airfoils. I've never experienced unexpected stalls---although got close a couple times circling low level filming moose. I think by and large Mr. Piper got it right---for me. I've never had a hankering for the others.
I'm no purist and slave to orthodoxy and know nothing of comparative advantages of airfoils. I've never experienced unexpected stalls---although got close a couple times circling low level filming moose. I think by and large Mr. Piper got it right---for me. I've never had a hankering for the others.
bob turner
Registered User
All you have to do to convince me is to name the aircraft that enjoys that better wing to the point where it is superior to the Cub in what the Cub does.
Bushwhacker Air
Registered User
New York
If memory serves me right, Mr. Piper inherited the USA-35B from the Taylors. The Taylors went on to use the NACA 23012 on the Taylorcraft - maybe thinking that was their ace-in-the-hole. Although the Tcraft performs better in areas, that venerable tandem design still won out!
When you do the numbers (and I'm not an airfoil engineer by any standard) the USA-35B - modified to be slighty taller as it is on the Piper Aircraft and many varients - is not a bad performer. Washout isn't a fix, it aids the stalling characteristics over the span of the wing panel.
I've flown the NACA 23012 on the Tcrafts, the USA-35B mod on the Cubs (clipped and full-span), and the NACA 4412 on Champs. They all flew a little different, but none were dangerous if you knew what to expect. I really like the way the 23012 performs on the Tcraft DCO-65 and L2-M's, and was planning on using it for my BushCub plane, but the purists just don't like change!
When you do the numbers (and I'm not an airfoil engineer by any standard) the USA-35B - modified to be slighty taller as it is on the Piper Aircraft and many varients - is not a bad performer. Washout isn't a fix, it aids the stalling characteristics over the span of the wing panel.
I've flown the NACA 23012 on the Tcrafts, the USA-35B mod on the Cubs (clipped and full-span), and the NACA 4412 on Champs. They all flew a little different, but none were dangerous if you knew what to expect. I really like the way the 23012 performs on the Tcraft DCO-65 and L2-M's, and was planning on using it for my BushCub plane, but the purists just don't like change!
I m not implying there is anything wrong with it, just seems there are more choices today. 23012 is very popular and use din many more planes than we know some bush variants. The helio uses the 23012 with no dihedral or wash.
The ribblett foils work very well and out perform the usa35b in my opinion for my style of flying but that is just my opinion. They do not need washout either. rig a usa35b without washout and you could get into trouble.
The ribblett foils work very well and out perform the usa35b in my opinion for my style of flying but that is just my opinion. They do not need washout either. rig a usa35b without washout and you could get into trouble.
35b
Gander, That is a pretty bold statement on a cub site for a non-contributing member! Or did I miss something? Not trying to start anything either but except for being slow in cruise I have never flown a wing that will hang in there like a cub that is set up right. I have also flown several with little to no washout and while the stall may be more abrupt it has never seemed dangerous Unless you over rudder it! The Tcraft wing won't carry anywhere near the load and still get off short and neither will a GCBC citabria.
Which wings that you have flown do better for STOL & heavy loads?
Dave
Gander, That is a pretty bold statement on a cub site for a non-contributing member! Or did I miss something? Not trying to start anything either but except for being slow in cruise I have never flown a wing that will hang in there like a cub that is set up right. I have also flown several with little to no washout and while the stall may be more abrupt it has never seemed dangerous Unless you over rudder it! The Tcraft wing won't carry anywhere near the load and still get off short and neither will a GCBC citabria.
Which wings that you have flown do better for STOL & heavy loads?
Dave
Don't get your feathers all ruffled up now. I also have a cub too. I do know a ribblett 64-66 is better for my application. I am not saying it is a bad airfoil just wondering why it was chosen over others. YOu cannot compare it to other planes with different airfoils, you need to put other airfoils on a cub airframe. Look at the vast differences there are in the cub line j-3 12-18-14-j5 ect.
feathers
Gander, First you need to tell us, What is your application? Is your experience with nasty power on stalls limited to your airplane or have you found this on several? What exactly does your airplane do in a power on stall? Maybe we can solve this with rigging or a angle of incidence adjustment. I learned to fly in a 59 A model that was field repaired and the angle of incidence was WAY off on one side. That airplane scared the crap out of me and a few others before we figured it out and fixed it. It belongs to a founding member on here now and flys great.
Yes I have flown a T-craft wing on a PA-18 fuselage. It was a great flying airplane with a 125 on it. It would take off pretty good light, go like hell in cruise but fell on its face with much of a load. And I've been told it didn't glide very good at all...What wings have you flown with a cub fuselage?
dave
PS: not ruffled at all just heard all this before in hangar sessions but no one has yet to prove it. ( case in point,,,Mountain Goat)
Gander, First you need to tell us, What is your application? Is your experience with nasty power on stalls limited to your airplane or have you found this on several? What exactly does your airplane do in a power on stall? Maybe we can solve this with rigging or a angle of incidence adjustment. I learned to fly in a 59 A model that was field repaired and the angle of incidence was WAY off on one side. That airplane scared the crap out of me and a few others before we figured it out and fixed it. It belongs to a founding member on here now and flys great.
Yes I have flown a T-craft wing on a PA-18 fuselage. It was a great flying airplane with a 125 on it. It would take off pretty good light, go like hell in cruise but fell on its face with much of a load. And I've been told it didn't glide very good at all...What wings have you flown with a cub fuselage?
dave
PS: not ruffled at all just heard all this before in hangar sessions but no one has yet to prove it. ( case in point,,,Mountain Goat)
My application is off airport bush flying usually with a load. I dont have a problem with the way it flys just wondering why the airfoil was used and there has been alot more testing and foils made since the late 40s. I am not one to just say well i guess that is just how it is. You've never thought i wonder or what if?? Try to think out of the box a little. Thats why i am asking to see what others have tried and maybe someone knows why piper chose the airfoils on so many of it planes and if they tried any other foils.
wings
What airplane with that wing have you seen outperform a super cub?
I would love it if you would post some good pictures from the front and side of your bird because if your getting your butt kicked by a ribblett wing I have a feeling either he has alot more horsepower than you or your cub has a AOI or engine problem.
Take Valdez for example, the J-3s win in that class the -11 or 90hp 18 win and the 150-180hp cubs win. so my question is where is the flying wonder with a ribblett wing and why have we not heard of it?
I have flown a streched pacer with the ribblett wing and 145 hp its fast but its not as slow.
Maybe if we could see pictures of your airplane we could figure out why is doggy on takeoff & has a nasty stall. Mark from Thrustline is a master at measuring fuselages with a digital level. You should contact him and get your measured.
dave
gander said:
What airplane with that wing have you seen outperform a super cub?
I would love it if you would post some good pictures from the front and side of your bird because if your getting your butt kicked by a ribblett wing I have a feeling either he has alot more horsepower than you or your cub has a AOI or engine problem.
Take Valdez for example, the J-3s win in that class the -11 or 90hp 18 win and the 150-180hp cubs win. so my question is where is the flying wonder with a ribblett wing and why have we not heard of it?
I have flown a streched pacer with the ribblett wing and 145 hp its fast but its not as slow.
Maybe if we could see pictures of your airplane we could figure out why is doggy on takeoff & has a nasty stall. Mark from Thrustline is a master at measuring fuselages with a digital level. You should contact him and get your measured.
dave
I think your pretty much missing my whole point here.. Who said anything about a ribblett kicking my butt. ANd comparing a pacer to a cub. just wondering why piper chose that particular airfoil and why. Did the cub with the taylor craft wing have flaps? Was it a taylor craft wing made to fit a cub or was it a cub wing built with taylorcraft ribs?? How was the center of lift decided compared to a taylor craft or helio?? Forget about the competition between airplanes i want to know more about the nuts and bolts.
Steve Pierce
BENEFACTOR
Graham, TX
Didn't the Helio start out as a Vagabond?
How about making up a set of ribs for a different airfoil and trying them on a Cub? I here there is an experimental Super Cub kit builder experimenting with that very thing.
How about making up a set of ribs for a different airfoil and trying them on a Cub? I here there is an experimental Super Cub kit builder experimenting with that very thing.
King Brown
Registered User
Nova Scotia
Why USA35B?
There were no extravagant claims by Mr. Riblett for his GAU 613.5 rib from two sources who heard Mr. Riblett speak: a homebuilder at an EAA Chapter 240 meeting and me, 16 November 1997.
Mr. Riblett told the EAAers that the improvement was good but not great, three to five knot higher speed and three knot lower stall compared to the Piper airfoil.
A typical engineer, he told me his ribs "were just clean-ups" of older foils of the 20s, better than the Cub's, and he mentioned the Montana Coyote and the Papa 5151.
Morgan Williams stuck to the Cub airfoil for his North Star, which aviation writers claimed as superior in performance to the Coyote. Mr. Riblett also said $60 a Riblett rib was "just too much."
There were no extravagant claims by Mr. Riblett for his GAU 613.5 rib from two sources who heard Mr. Riblett speak: a homebuilder at an EAA Chapter 240 meeting and me, 16 November 1997.
Mr. Riblett told the EAAers that the improvement was good but not great, three to five knot higher speed and three knot lower stall compared to the Piper airfoil.
A typical engineer, he told me his ribs "were just clean-ups" of older foils of the 20s, better than the Cub's, and he mentioned the Montana Coyote and the Papa 5151.
Morgan Williams stuck to the Cub airfoil for his North Star, which aviation writers claimed as superior in performance to the Coyote. Mr. Riblett also said $60 a Riblett rib was "just too much."
Bushwhacker Air
Registered User
New York
I know my 65 hp Tcraft BC12 would not perform with 2 aboard as well as the 65hp Cub - about the same weight - that's my limited experience with the 2. The L2-M flew great - was never really loaded up and 85 horses to boot.
Alaskan William Fike did a lot of work with the Riblett Airfoil for his low-aspect ratio wing and put one on a Supercub if I remeber correctly. Does anyone know how that performed?
Like I said way back, I think Piper inherited the USA-35b and it worked. Back then, the adage "if it ain't broke, don't fix it" probably was used a lot more - especially when you were getting planes out the door as fast as Piper did!
Alaskan William Fike did a lot of work with the Riblett Airfoil for his low-aspect ratio wing and put one on a Supercub if I remeber correctly. Does anyone know how that performed?
Like I said way back, I think Piper inherited the USA-35b and it worked. Back then, the adage "if it ain't broke, don't fix it" probably was used a lot more - especially when you were getting planes out the door as fast as Piper did!
True about the riblett just a few knots on the top and bottom but an improvement, i do know where it shines is hauling a load. Any other airfoils out there that are suppose to be superior??? I have a copy of the mt. goat airfoil but have not disected it and run the numbers yet, according to several guys i talked with who have flown it they said it was fast but not much if at all slower and had to be flown by the numbers. I would not consider using the airfoil as it does not suit my style of flying. Earny Heald talk highly of the ribblett air foil but he was selling it.
Steve, I've considered building a composite rib ,leading edge and false spar in composite and attaching it to standard cub frame work and tweak flap and aelerons just trying to figure out which one is worth doing, Several guys up here are really interested in it. The helio did start as a vagabond.
Steve, I've considered building a composite rib ,leading edge and false spar in composite and attaching it to standard cub frame work and tweak flap and aelerons just trying to figure out which one is worth doing, Several guys up here are really interested in it. The helio did start as a vagabond.
Darrel Starr
Registered User
Plymouth, MN
I have no opinion on the subject, just some information to share so you all can visualize better the shapes of the various airfoils. As I recall, this information was in the EAAs Vintage publication. Keep in mind that the ragwing pipers have a "modified" -35B airfoil so someone was thinking, not just doing what someone else had done.
Darrel
Here is the unmodified -35B shape.
The Clark Y was on the Monocoupe, Travelair and MANY other 1930s planes.
The Taylorcraft Airfoil 23012
And the 8KCAB Decathlon Airfoil NACA 1412
Darrel
Here is the unmodified -35B shape.
The Clark Y was on the Monocoupe, Travelair and MANY other 1930s planes.
The Taylorcraft Airfoil 23012
And the 8KCAB Decathlon Airfoil NACA 1412
bob turner
Registered User
Neat, Darrell! Thanks!
No question that nobody has yet built a Cub better than the Piper Cub (or its able clones).
But Gander's question perhaps could be rephrased: Why not?
Let me ask the same question about engines and magnetoes - why are we still using ignition systems off of a farm tractor designed in 1928? Or engines that load up thirty dollar sparkplugs with regularity? I just heard that at least CC has integrated ignition systems in an experimental that use auto spark plugs - and that he welds up a Lycoming oil pan to save weight. That may be hearsay, but the fact remains that the good things for folks who love Cubs were mostly thought up in the 1930s, and sometimes the originals are better than the improved versions (think "wing ribs?").
Opinion.
No question that nobody has yet built a Cub better than the Piper Cub (or its able clones).
But Gander's question perhaps could be rephrased: Why not?
Let me ask the same question about engines and magnetoes - why are we still using ignition systems off of a farm tractor designed in 1928? Or engines that load up thirty dollar sparkplugs with regularity? I just heard that at least CC has integrated ignition systems in an experimental that use auto spark plugs - and that he welds up a Lycoming oil pan to save weight. That may be hearsay, but the fact remains that the good things for folks who love Cubs were mostly thought up in the 1930s, and sometimes the originals are better than the improved versions (think "wing ribs?").
Opinion.
Darrel Starr
Registered User
Plymouth, MN
Bob, the CC Sport Cub is very innovative. Here is the oil pan -- it does appear to be a weldment.
Darrel
Darrel
Maybe Mr. Wayne Mackey will chime in...What airfoil did he use for the Mud Hen? I looked at those wings..Huge cord...with fixed leading edge slat...would really like to have those...it could really fly slow...not sure, but I think it was not very fast.
Good Thread Gander!
Ron
Good Thread Gander!
Ron
pictures
Gander, I really would like a look at your Cub. Of all the cub models and planes I have flown the only ones with nasty stall habits could be traced to out of spec. fuselages or rigging problems.
Has anyone ever measured your plane? What model do you fly?
Don't knock pacers, with long wings they will do amazing things and are actually pretty light. I think the 125 pacer I owned for awhile was under 1000lbs. Might have even been close to 950 if memory serves.
As far as stall spin accidents in cubs I think to much bottom rudder in steep turns is mostly the cause in most cases. most cubs will give you alot of warning before paying off if flown centered.
dave
Gander, I really would like a look at your Cub. Of all the cub models and planes I have flown the only ones with nasty stall habits could be traced to out of spec. fuselages or rigging problems.
Has anyone ever measured your plane? What model do you fly?
Don't knock pacers, with long wings they will do amazing things and are actually pretty light. I think the 125 pacer I owned for awhile was under 1000lbs. Might have even been close to 950 if memory serves.
As far as stall spin accidents in cubs I think to much bottom rudder in steep turns is mostly the cause in most cases. most cubs will give you alot of warning before paying off if flown centered.
dave
ag pilot my fuselage is new and it came from airframes it fly great what i was getting at was the ribblett has a softer stall than the cub airfoil maybe nasty was not such a good word to use. could it be possible if a person was to build a different rib it may by a bit better than a cub rib?? Of coarse used on a super cub airframe.
wings
Gander, Don't let the fact that your fuselage is new fool you. I have seen several that were not right that were brand new. The cub I fly now is a 74 that had one owner before me and 379 hrs TT never wrecked or dinged. We assumed it would be right and never used a digital level on it till after it was covered and I wasn't happy with its slow speed flying. Turns out it is a bit short of AOI right from the factory.
As far as a different rib working better nothing is impossible but this has been tried for years on and so far for the kind of performance I want out of my cub the only thing I have seen that is way slower is Wayne Mackey's slats. Jerry Burr has a cuff and I think that helps some to but the stock wing with micro VGs seems to be a safe predictable combination. Then you add some HP and Marks Thrustline Mod and its about perfect for what I do.
Measure the AOI on your plane, That is the only way you will know what you have for sure.
dave
Gander, Don't let the fact that your fuselage is new fool you. I have seen several that were not right that were brand new. The cub I fly now is a 74 that had one owner before me and 379 hrs TT never wrecked or dinged. We assumed it would be right and never used a digital level on it till after it was covered and I wasn't happy with its slow speed flying. Turns out it is a bit short of AOI right from the factory.
As far as a different rib working better nothing is impossible but this has been tried for years on and so far for the kind of performance I want out of my cub the only thing I have seen that is way slower is Wayne Mackey's slats. Jerry Burr has a cuff and I think that helps some to but the stock wing with micro VGs seems to be a safe predictable combination. Then you add some HP and Marks Thrustline Mod and its about perfect for what I do.
Measure the AOI on your plane, That is the only way you will know what you have for sure.
dave
jnorris
MEMBER
Wisconsin
gander said:
First thing you have to remember is that the choice was originally made in the 30s (maybe even late 20s) by C. G. Taylor. While there are all kinds of airfoils to choose from today, there weren't as many back then (no Riblett or NACA yet) and not as much was known about aerodynamics as we know now. When compared to what a lot of other manufacturers were using at the time of the original choice, I think the USA35B holds up pretty well.
And as for stall-spin accidents, if you go back and look at safety records from the 40s you'll find that the Taylorcraft was much more commonly involved in stall-spin accidents than the Cub was. But then as now, stall-spin is much more about pilot technique and awareness than the specific airfoil involved.
Ok, so your next question might be "if the USA35B was the best choice of the time why did Piper stick with it when newer "better" airfoils became available?" Well, the only people who can accurately answer that question would be Walter Jameneau and the Piper design team, but I believe part of the reasoning could very well have been Piper's common practice of sticking with what's known and what's already "on the shelf". Look at how many parts are interchangeable between different "Cub" models. There is a LOT of commonality throughout the fabric-covered Piper line. It was Piper's way of doing things. Also, the cost of certificating an entire new airplane (which would have been required if the wing airfoil was changed) was considerably more than sticking with what was already proven and approved, so Piper once again took the path of least resistance.
Judging by the success and popularity of the Piper Cub line of aircraft, I'd tend to think that they made the right decision!
bob turner
Registered User
That implies that there is a better airfoil for the Cub, and inertia has kept us from using it. So what is it, and why didn't CC use it? Seems like if there is enough interest in slotted wings to get an STC, there ought to be even more interest for a better wing.
