Cub v.s. Taylorcraft airfoil performance

[astjp2]

Taken from the D&E website
Cubby Comparision Statistics
J3 Cub / 85 HP Con. Prop 70-44

Cub Airfoil........................................... Taylorcraft Airfoil
Cruise at 2150 rpm - 62 mph.................Cruise at 2150 rpm - 84 mph
Cruise at 2300 rpm - 72 mph.................Cruise at 2300 rpm - 91 mph
Full throttle 2570 rpm - 84 mph..............Full throttle 2570 rpm - 100 mph
Stall - 41 mph.....................................Stall - 42 mph
Rate of Climb - 950 fpm........................Rate of Climb - 850 fpm
Takeoff - 280 ft..................................Takeoff - 325 ft
I dont think that most pilots will notice the difference between the 45' of takeoff roll but the economy cruise sure will show in the pocket book

[paulnuss]

Re: Cub v.s. Taylorcraft airfoil performance

Who is D&E? I pretty much agree with the numbers from my own experience, Cub vs. Taylorcraft, but don't recognize the data source. And I was wondering, are these numbers for Cub vs. Taylorcraft airframe, or a Cubby with two different airfoils? A Google search brings D&E up as something rather awful...

[astjp2]

Re: Cub v.s. Taylorcraft airfoil performance

http://www.de-aircraft.com/

[KewFlyer]

Re: Cub v.s. Taylorcraft airfoil performance

And they are even selling an F21 and a BC12-D fuselages from factory !!!.

[Hank Jarrett]

Re: Cub v.s. Taylorcraft airfoil performance

When Taylor built the first Taylorcrafts he used the "tried and true" methods of the day that included the original Cub airfoil. The first was that Taylor actually READ & STUDIED the current state of the art. Piper was an "Oil Man" and was a great business man, but didn't know squat about aerodynamics or aircraft design.
If you look at the bottom of a Cub wing, then a Taylorcraft wing you will see a BIG chunk of why the Taylorcraft is so much more efficient. The bottom of a Cub wings airfoil is FLAT from the front spar to the leading edge radius. On the Taylorcraft the bottom surface curves up to the leading edge in what is called a "Phillips Entry" that significantly reduces drag. The second major drag reduction was in the taper of the fuselage aft of the wing. It reduced the surface area of the fuselage to reduce drag. Taylor also added hundreds of small drag and weight reduction ideas to the Taylorcrafts that all added up to some pretty significant improvements. I have heard that Piper never did figure out how he was doing it.
All of this came out in NACA tech pubs that would put normal people to sleep, but guys like Taylor ate it up.
Hank

[paulnuss]

Re: Cub v.s. Taylorcraft airfoil performance

My thoughts were that the drag reductions in the Taylorcraft airframe vs the Cub airframe were indeed due to more than the airfoil. Fuselage shape, landing gear design, many items all had a part. I wondered if someone had tested a "Cubby" type with Taylorcraft's 23012 airfoil and found that big a difference in speed. I have attended the Piper Cub Fly-In at Lock Haven several times, which is only about 70 miles from my home base, flying up in my Taylorcraft. I always tell the Cub types who come around that it is the "much-improved Cub"; when Mr. Taylor looked at the Cub and decided he could do better! It brings out a chuckle, or a rise. So far, no one has hit me! ;-)

[M Towsley]

Re: Cub v.s. Taylorcraft airfoil performance

Paul,

It is true, it is an improvement over the over-hyped Cub. Just because it has cult status doesn't mean it is better. In this case it is slower and way overpriced.

It is too bad they didn't use 65hp as a comparison between the two. That would have been more accurate for the time. I will give the Cub one thing compared to the Taylorcraft, that flat-bottomed wing does climb better than the 23012. When I had my L-2 I flew to an event with an L-4. He way out-climbed me but I had to keep throttling back to keep from running away from him. And an L-2 is much draggier than a BC-12.

I cannot remember if it was in Chet's book, or where I read it, but allegedly CG Taylor flew next to or somehow observed a Cub in flight and noted where the covering was pulling away in spots due to the airflow. Then he designed a better plane based on his observations. Again the L-2 has some drag issues over an L-2 but when you look at the frontal area of a Cub or L-2 it is obviously narrower than the BC-12 and you would think it would be faster, but the BC-12 is much more efficient as a side-by-side.

[N96337]

Re: Cub v.s. Taylorcraft airfoil performance

I used to have a friend with a J3C-90.... I'd go fly with him with my 85hp Tcraft with the short mount and go much faster, just as slow, and get in and out of anywhere he could....sure burned his bacon! The best part as far as I was concerned, was that I'd spent about 25% as much on my purchase of a far superior airplane as he had.....
John

[3Dreaming]

Re: Cub v.s. Taylorcraft airfoil performance

The numbers that are posted are for the same airframe (or type airframe) with the 2 different types of airfoils. If the T-Craft airfoils was on a B model T-Craft then the speed numbers would have been faster.

[Robert G. Hamm]

Re: Cub v.s. Taylorcraft airfoil performance

Luckiest guy here! Have both a J3-C65 and a BC12D. Both with A65’s and configured the way they came from the factory. It depends on what your goal is for flying as to which airplane to take. If you want to get to your destination the Taylorcraft is the choice. But if you want to take your time and do not care that fueling up is about a 100 miles away, then the J3 is better to be in. Bern Heimos took his J3 from California to the Hudson River and back in only 32 days. The pictures are great to see. Most are taken with the door down, and both windows open. This configuration slowed the Cub to 66 MPH average but substantially increased the enjoyment. Two long trips in the J3 were from HLN to UAO then back to HLN when we moved home. The direct route took 9.1 hours at about 70 MPH with 4 fuel stops.
Bought the BC to replace the Luscombe 8A I had just sold. The stability (in the air), rate of climb and cruse speed was more like the Luscombe 8A then the J3. Also having 18 gallons of fuel instead of the 14 in the 8A fit what I wanted for cross country flights. Four gallons does not seem like much but in miles is about 90 miles more down the path. Even with a constant head wind the BC averaged 90 MPH from Éclair, WI to Helena, MT. Not too shabby! My old 1966 C-172 did not do much better and burned twice the fuel.
The differences make it fun to own both.

[flyguy]

Re: Cub v.s. Taylorcraft airfoil performance

Deleted my comments above as I was careless reading and didn't see the cubby/airfoil thing. Duh.
Interesting comparison.
DC

[shipljl]

Re: Cub v.s. Taylorcraft airfoil performance

In the early days, NACA came up with lots of airfoils that were very efficient but had discontinuous lift drag curves at the stall point. This means that you get such an abrupt stall that it can be dangerous. If one wing stalls first you get a dangerous wing drop on one side, not something you want to happen in even a good full stall landing.

Apparently Taylor liked the high efficiency of the airfoil and dreamed up a solution: put some washout into the wing so that the stall progressed from the root to the tip as angle of attack is increased. This way only a small portion of the span is experiencing the abrupt portion of the stall at any time and the wing behaves much more docile, just like the Cub's Clark Y airfoil. This is why 2 degrees of washout is required when rigging the Taylorcraft wing.

This way we get most of the performance of the more efficient airfoil without the nasty stall characteristics.

A similar technique is used on tapered wings to make them stall at the root first.

[resojames]

Re: Cub v.s. Taylorcraft airfoil performance

In the early days, NACA came up with lots of airfoils that were very efficient but had discontinuous lift drag curves at the stall point. This means that you get such an abrupt stall that it can be dangerous. If one wing stalls first you get a dangerous wing drop on one side, not something you want to happen in even a good full stall landing.

Apparently Taylor liked the high efficiency of the airfoil and dreamed up a solution: put some washout into the wing so that the stall progressed from the root to the tip as angle of attack is increased. This way only a small portion of the span is experiencing the abrupt portion of the stall at any time and the wing behaves much more docile, just like the Cub's Clark Y airfoil. This is why 2 degrees of washout is required when rigging the Taylorcraft wing.

This way we get most of the performance of the more efficient airfoil without the nasty stall characteristics.

A similar technique is used on tapered wings to make them stall at the root first.

That is odd about the stall characteristics. I built a Clip Wing T Craft and rigged it no dihedrial nor wash out and it still retained the docile stall characteristics. I always thought it was one of the most forgiving airplanes ever built.

[Hank Jarrett]

Re: Cub v.s. Taylorcraft airfoil performance

Some of the early NACA airfoils DID have a vicious stall. The one on the Taylorcraft isn't one of them. It is one of the most common GA airfoils in use even today because of it's good handling. A couple of things it DID give up were that, unlike a Cub airfoil, it will not naturally pull out of a dive, especially after a stall, like the Cub will. It also has some less desirable characteristics when flapped (remember that an aileron is just a flap that goes both ways). One reason people think a Taylorcraft is a "floater" is they stop slowing the wing down when the ailerons get sloppy. The airfoil is NOT close to a stall just because the ailerons start loosening up. Those who have flown them for a while know how they handle at low speeds and are used to the aileron "slop" when slow. A Cub driver will try to land too fast to keep crisp aileron control and float down a 5,000' runway, complaining that a Taylorcraft won't land. NOT TRUE! It just won't land like a Cub.
If you are having trouble landing as short as guys say they can on the group, go up and practice some slow flight (DO IT HIGH!!!) until you are comfortable with when the wing will really stall. One thing I REALLY want to do on my plane when she is up again is to put an AoA probe out on the strut to measure the stall characteristics.
As for washout, RIG IT LIKE THE SPECS SAY! If you smash up your plane the accident investigation is going to hang you if they find you were out of rig messing with the washout. YES, it will fly nice aerobatics with a flat wing, but that is NOT for a sport pilot! The washout makes the wing more stable and caused a progressive stall from root to tip. If you aren't flying aerobatics you do NOT want a flat wing or no twist in the wing, especially in an accelerated stall. Talk to a good aerobatic pilot about what happens to non-aerobatic pilots when a plane is rigged for maneuvering like his is. You can get in a LOT of trouble really fast by taking the dihedral and twist out of your wing.
Hank

[Robert G. Hamm]

Re: Cub v.s. Taylorcraft airfoil performance

One short thought about the two designs. How many J3’s are flying in Alaska? Even with the C-85 in a J3, the Taylorcraft still wins!