A numbers rebuttal to folks trashing Cub wing performance

[Alex Clark]

On another web site there was a discussion that started out with folks talking about the Alaskan Super Cub as being more dangerous to fly at slow speeds. Causing stall-spins (know as Moose Hunter spins here) Some then replying that the champ wing was able to maintain steeper banks with more control. Sighting the fact that they had seen fewer Champ accidents.

Below is my response.

The which plane is more dangerous subject comes up from time to time. Here it appears to be a Champ vs Cub question. Some people thinking that the Cub type wing is not forgiving in steep banks and thus more likely to stall and spin into the ground at low airspeeds. As is ANY PLANE.

Here are some number from the FAA and NTSB. Note that I probably missed some of them. It is hard to get the sites working today. So if I goofed on the numbers it is not for lack of trying.

Number of Aircraft registered in Alaska. 10,581
Number of Alaskan Resident Pilots…….10,613

Number of Piper Cub Type Aircraft Registered to Alaskan owners. (2,250)

PA-18…1,471
PA-12…..475
J-3s……..165
PA-11……92
J-5s………47

Number of Champ/Citabria type planes registered to Alaskan Owners. (391)

7GCBC…175
8GCBC….65
7ECA……61
7AC……..90

Number of Aircraft accidents of all types in Alaska for the last 10 years: (1368)

Number of Aircraft accidents involving fatalities in Alaska in last 10 years: (131)

Total Accidents in Cub Type aircraft last 10 years: (253) (11.5% of Alaska Cubs)
Fatal aircraft accidents during last 10 years involving Cub Type aircraft (12) (5%)

PA-18….200 accidents…10 fatal
PA-12….44 accidents……2 fatal
PA-11….4 accidents……. 0 fatal
J-3……..3 accidents……..0 fatal
J-5…….2 accidents……. 0 fatal

Number of Alaskan Aircraft accidents involving Champ/Citabria type craft: (34) (8.7% of Alaskan type ownership)
Number of fatal accidents involving Champ and Citabria type craft in Alaska. (2) (6%)

7GCBC…17 accidents…1 fatal
8GCBC…11 accidents…1 fatal
7ECA…..4 accidents…0 fatal
7AC…….2 accidents…0 fatal

For comparison purposes there were 525 Cessna aircraft accidents in Alaska during the same 10 year period. 54 were fatal. (10.3% fatal)

De Havilland products (Beavers, Otters) during the same period had 69 accidents in Alaska with 12 of those being fatal. (17.5 % fatal)

Thus the Champs are not actually any safer or less likey to be involved in an accident than a CUB type aircraft. There are simply few of them.
Nor is a Cessna safer under the same conditions. xx

 

[rrb]

Couldn't there also be some quantifiable comparison of the lift curves of the various airfoils? Doesn't the Champ use a NACA 4412 and the Cub a modified USA 35B? I'm no engineer so I only beg the question.

 

[Alex Clark]

Well if it gets you all hot and bothered here you go. But the whole point was that Supercubs are not falling out of the sky any more than any other planes....

Piper J-3 Cub (L-4, NE-1) USA 35B
USA 35B
Piper J-4 Cub Coupe USA 35B
Piper J-5 Cub Cruiser USA 35B
Piper PA-11 Cub Special USA 35B
Piper PA-12 Super Cruiser USA 35B
Piper PA-14 Family Cruiser SA 35B
Piper PA-15 Vagabond USA 35B
Piper PA-16 Clipper USA 35B
Piper PA-17 Vagabond Trainer USA 35B
Piper PA-18 Super Cub USA 35B
Piper PA-19 Super Cub USA 35B
Piper PA-20 Pacer USA 35B


Champion 7EC Traveler NACA 4412
Champion 7GC Sky-Trac NACA 4412
Champion 7GCB Challeng NACA 4412
Bellanca 7ACA Champion NACA 4412
Bellanca 7ECA Citabria NACA 4412
Bellanca 7GCAA Citabria NACA 4412
7GCAB Citabria NACA 4412
Bellanca 7GCBC Scout NACA 4412
Bellanca 8GCBC Scout NACA 4412

Cessna 120 NACA 2412

Cessna 140 NACA 2412
Cessna 140A NACA 2412
Cessna 150 NACA 2412
NACA 0012
Cessna 152 NACA 2412 NACA 0012
Cessna 170 NACA 2412 NACA 2412
Cessna 170A NACA 2412 NACA 0012
Cessna 172 Cutlass NACA 2412 NACA 2412 mod
Cessna 172 Hawk XP NACA 2412 NACA 2412 mod
Cessna 172 Skyhawk 1973-later NACA 2412 NACA 2412 mod
Cessna 172 Skyhawk early models (T-41) NACA 2412 NACA 0012
Cessna 175 Skylark NACA 2412 NACA 0012
Cessna 177 Cardinal 1967 only NACA 64A215 NACA 64A212
Cessna 177 Cardinal 1968-later NACA 2415/64A215 NACA 2412/64A212
Cessna 180 (U-17) NACA 2412 NACA 0012
Cessna 182 1972-later NACA 2412 NACA 2412 mod
Cessna 182 early models NACA 2412 NACA 0012
Cessna 185 (U-17) NACA 2412 NACA 2412 mod
Cessna 187 NACA 2412 NACA 0012
Cessna 188 AgWagon 1972-later NACA 2412 NACA 2412 mod
Cessna 188 AgWagon early models NACA 2412 NACA 0012
Cessna 188 AgWagon prototype NACA 2412 NACA 2412 mod
Cessna 190 NACA 2412 NACA 2412
Cessna 195 (LC-126) NACA 2412 NACA 2412
Cessna 205 NACA 2412 NACA 0012
Cessna 206 Stationair 1971 NACA 2412 NACA 0012
Cessna 206 Stationair 1972-later NACA 2412 NACA 2412 mod
Cessna 206 Super Skylane NACA 2412 NACA 0012
Cessna 206 Super Skywagon NACA 2412 NACA 0012
Cessna 207 Skywagon NACA 2412 NACA 0012
Cessna 207 Stationair NACA 2412 NACA 0012
Cessna 208 Caravan (U-27) NACA 23017.424 NACA 23012
Cessna 208B Grand Caravan NACA 23017.424 NACA 23012
Cessna 210 1967-later NACA 64A215 NACA 64A412
Cessna 210 early models NACA 2412

 

[rrb]

Alex I wasn't trying to poke any holes into your analysis. The statistics are interesting.

I was just wondering what any actual differences in the airfoils were. I was hoping to bait someone with more math and physics knowledge than I have into the fray.

 

[bob turner]

Roll in to a steep bank and pull as hard as you can, and it really doesn't make any difference what wing you are flying - they can break pretty quickly. But it requires some real pulling -

 

[Samsam]

I was just wondering what any actual differences in the airfoils were. I was hoping to bait someone with more math and physics knowledge than I have into the fray.

That would be interesting to see.


Isn't the SC better suited for off airfield operation than a 7GCBC? (performance/useful load/etc) If so, it stands to reason that a typical SC pilot (especially commercial ) operates out of shorter strips and less "forgiving" environment? Maybe the typical SC pilot is simply exposed to a higher risk

 

[scout88305]

I know several old-timers that started spraying in Cubs and Champs. They have both told me they preferred the Champ wing when they got to the end of the row. I am going to email them and ask why and then post it.

 

[Alex Clark]

Low and slow , along with steep banks, can also be REALLY affected by the aileron movement available and Rudder size.

Fly an old C-206 and then fly a newer C-206 with a seaplane rudder.. Night and day at low speeds.

 

[mvivion]

Alex,

Just a clarification. The 206 has, until the newest versions, ALWAYS been offered with two rudders, one a landplane rudder and one a seaplane rudder, with deeper chord and longer span.

Your statement that the newer airplanes have bigger rudders is actually wrong. Cesnna no longer offers the seaplane rudder on the new Model 206. They only offer the landplane rudder.

So, if you purchase a brand new 206 and you want to put it on floats, you'll have to go talk to Wipaire, and buy another rudder and tail cone.

The earliest 206 aircraft, with a float kit, had the bigger rudders.

MTV

 

[Widebody]

Re: A numbers rebuttal to folks trashing Cub wing performanc

The which plane is more dangerous subject comes up from time to time. Here it appears to be a Champ vs Cub question. Some people thinking that the Cub type wing is not forgiving in steep banks and thus more likely to stall and spin into the ground at low airspeeds. As is ANY PLANE.
-------------------------------------------------------------------------------------

1. Since when did a stall, put an airplane into a spin?
2. Degree of Bank angle has nothing to due with a spin.
3. A Moose stall only happens when cross controlled and it doesn't matter what the bank angle is. High wing snaps over the top in a cub and at low agl your dead, not much time for a spin either.

The pilot controls whether the airplane enters a spin.
You can stall an airplane in a 60 degree bank all day long if you're coordinated and never enter a spin.

Pilot error is what gave the Cub a bad rap and it happened more often because it was and always will be a more popular work plane than the Champ. A lot of pilots died in Moose stalls and the same thing with all of the base to final crashes. The airplane doesn't just roll over and crash, the pilot causes this by stalling and then amplifies it by trying to cheat the turn. Fly coordinated and your pretty safe no matter what your're doing.
All pilots make mistakes, myself included, but some mistakes we can't afford to make.

As far as which is safer, I'll choose metal over wood any day. Just my opinion.

 

[Sam Beckett]

Widebody,
Good answer...

Alex,
You have way too much time on your hands.....

SteveJ,
Didn't you need some Christmas Envelopes stuffed.....???


Sam



8)

 

[JimC]

I've flown cubs for 41 years, dearly love them and would never want to trash them. That said, I have a few comments.

If I remember correctly, the cubs use a 35Bmod airfoil rather than the 35B.

When I learned to fly in 1965, cubs had the third highest fatality rate per hour flown of any aircraft.

The data quoted earlier doesn't allow the fatality rate per hour flown to be computed and compared for cub types vs. champ types. This would probably be the most direct way to compare the relative safety.

Mark Drela's XFOIL software will calculate the pressure and moment curves for the cub and champ airfoils.

 

[scout88305]

Here is one crop dusters memories.

The wing wasn't an issue.

In June of 1962 I began a crop dusting career that lasted until 1965
when I was
hired by Northwest Airlines as a pilot. The crop dusting took me from
South
Dakota to Northern Minnesota to North Carolina and Virginia and finally
to the Sudan in Africa.

The first airplane was a 90hp no electric Aeronca Champ with a 65 gal
seat
tank where the back seat is in a champ. The tank could be used as a seat

when empty.
We were always spraying with full gas (78 lbs) and full spray tank at
about 520 lbs.
We were using the county two lane roads for runways and the spring wheat
fields were big and flat. The biggest worry was the power lines.
The Champ was good for flying right up a line of trees or power line and
climbing it, but
because it was underpowered with a full load you would have to milk
around a turn, no fancy tight turns.
From South Dakota and Minnesota we went to the mountains of North
Carolina and Virginia. Here we sprayed tobacco with insecticide and
farm fields with defoliant, which later became known as Agent Orange.
We were using 150 hp Piper Super Cubs (18 A's) with110 gal tank right
behind the pilot's head. The fields were so small and in the mountains
that we would only fly with about 50 gals of spray and not much gas. I
soon learned that the Super Cub could not walk right up to the trees and
climb them like the Champ. The advantage the Cub had was the power. So
even if you took a few branches with you, the Cub could power it's way
around the turn.
From there we went to Norfolk, Virginia to spray beans. Here we used
real airports so we would fill the tank with spray, about 880 lbs. The
Super Cub became an absolute dog at these weights, and for the first few
passes you had to hold forward elevator pressure because it could not be
trimmed. I thought this was about as bad performance as I would see,
wrong.

The next year 1963 we started in South Dakota in June but from there I
went to Sudan, Africa.
We were part the US Aid program, spraying the Nile river with defoliant
and locust with DDT.
The airplanes were 180 Cessna's with 100 gal Sorensen belly tanks. We
were spraying in 120 plus degrees. Now this was the real dog of the
bunch. It was so hot that we had to remove the cowl doors to keep temps
out the red and we often took 3000 to 4000 ft takeoff roll. It was
easier to trim in the turnarounds until the load was down a little.

I have about the same amount of time in each airplane. I would prefer
the Champ because of the control response, the room in the cockpit and
the visibility.

Ronald Powers

 

[Widebody]

scout,

It must be a champ, supercub thing again. The old boys around here tell the same story only reversed. They claim the champ had poor elevator
response and that you better pull back early or you wouldn't make the wires, and that the PA18A/150 was a dream to fly with all that HP, although they do talk about hot oil temps and eventually adding another oil cooler. It's fun listening to the old stories, I think they get better with time.

 

[scout88305]

I'm betting you are right WB. I'd take one of each and you'll never here me bitch about either one.

These old salts are getting to be fewer all the time. I just listen to what they say.

 

[Alex Clark]

Mike
Actaully I was right... and
You are right..
I actually left something out, I was referring to the older 206s with the smaller tail surfaces. (before 68 or 69) Many of which have had the larger horizontal surfaces installed and the seaplane rudder installed over the years. Although I have flown a couple that were supposedly factory float kitted (70s era) and not changed by the 135 operators AIs. That is what I was referring to as the older 206s (the old chin type) vs the newer ones, (post 69).

Thus I was talking about flying the larger tail with the float rudder installed vs the older smaller tail without that rudder. How the tail surfaces got there does not matter. I was talking about how they fly.

There is a big difference on how they handle at low speeds. The older pre-68 tail feathers must be 6 inches narrower.

xx

 

[Samsam]

Here is one crop dusters memories.

Cool story, Scout. Thanks for posting it. 8)