This gives me and my little Cherokee some hope for somewhat decent stol performance.

https://www.youtube.com/watch?v=ZY-SITE1Yks

TxKiger,

Regardless of engine or any modifications, it is critical to understand that the technique here gave him the great performance. All landings and all but the one takeoff used the maximum (lowest) ground effect available. On landing the extra kinetic energy created by ground effect allowed a slower than Vso speed at touchdown. On all takeoffs except the one where he stayed on the ground until he pitched up to Vx, he got first the nose wheel and then the mains off in slower than Vso flight. He then immediately pitched down to stay in as low as possible ground effect until maximum kinetic energy of pressure airspeed was created on the lifting surfaces before pitching up to Vx. This extra energy was used to zoom up over a fictional obstruction.

The Cherokee, while short winged and heavy for the 0-320, can take better advantage of low ground effect than a high winged airplane. Another advantage is that you have a wing to absorb energy in a crash before your body comes to a stop. But few, other than crop dusters, consider that advantage. You also can see much better in a turn.

Best regards,

Jim

The Cherokees meet or beat Cessnas for takeoff and landing distances with comparable weights and HP by the book values, and seem to back it up in practice. The 235b performs almost identically to my 182 when taking off. It might even be slightly better in climb.

While there's no doubt that some airplanes have better STOL performance than others, the fact is that it's pilot technique which makes the real difference, right?

Cary

Anybody ever flew a Cherokee with a stol kit? I've been thinking about putting one on mine, but I've never flew one with or know anybody who has.

hey Tx when you find out about that stol kit..you mite want to get ahold of this guy on https://www.youtube.com/watch?v=MQ1TzRrXDxo
looks like he can use some help with that Dang turbulence....or it could at least help that poor girl in the back seat...

contactflying wrote:......maximum kinetic energy of pressure airspeed ......

What do that mean?

I don't know how close a dakota is to a cherokee, but I was pleasantly surprised with the takeoff performance of the one I flew. Would have no reservations taking it in short on an unimproved, but smooth dirt/grass runway.

hotrod150 wrote:

contactflying wrote:......maximum kinetic energy of pressure airspeed ......

What do that mean?

Staying in low ground effect to accelerate to the highest airspeed you can safely achieve before pulling into a climb.

Once you commit to the climb you can trade off the excess airspeed over Vx to zoom climb and get more altitude in the same amount of horizontal space.

Since there's so much less induced drag at low ground effect you can gain more energy faster (airspeed = kinetic energy), and then you can trade that kinetic for potential energy (altitude = potential energy).

It's a great short field / obstacle avoidance technique once you're familiar with it.

Practicing with a CFI familiar in the technique is a good idea if you're thinking about trying it!

Excellent explanation, Cam Tom 12,

Garyowen,

Apache 21

CamTom12 wrote:

hotrod150 wrote:

contactflying wrote:......maximum kinetic energy of pressure airspeed ......

What do that mean?

Staying in low ground effect to accelerate to the highest airspeed you can safely achieve before pulling into a climb. Once you commit to the climb you can trade off the excess airspeed over Vx to zoom climb and get more altitude in the same amount of horizontal space....

I'm familiar with ground effect, and with getting some airspeed while still in ground effect, I just didn't get the max kinetic energy of pressure business. No offense, Contact, but while I'm sure your techniques & explanations thereof make a lot of sense, sometimes your wording throws me for a loss.

Out Front, Contact!

hotrod150 wrote:
I'm familiar with ground effect, and with getting some airspeed while still in ground effect, I just didn't get the max kinetic energy of pressure business. No offense, Contact, but while I'm sure your techniques & explanations thereof make a lot of sense, sometimes your wording throws me for a loss.

True, sometimes the words can be a little confusing.

For anyone else that's reading along and wondering:
Pressure airspeed is literally what makes an airplane fly. The different flavors of pressure airspeed (observed, indicated, calibrated, and equivalent) are all directly related to the total pressure read by the pitot tube minus the ambient pressure read by the static ports. The major differences lay in error corrections, but they are all directly proportional to the air flowing over the lifting surfaces.

True airspeed is an airplane's speed relative to the undisturbed airmass its flying in. It can't be calculated from the pressure airspeed without some pitot-static tap-dancing. It's useful for navigation.

Hotrod 150,

Sorry about the wording. I try not to teach a technique without explaining why the technique works. Wolfgange Langewiesche, in "Stick and Rudder" explains that airspeed is altitude and altitude is airspeed. That energy transfer takes place in the energy management turn at altitude as well. Extra energy, besides the energy management transfer of airspeed to altitude and altitude to airspeed, is created by reaction of the down wash of air from the trailing edge of the wing impacting the ground. Also, the trapped bubble of air between the wing and ground provide a slick cushion for the wing to ride on. There is hugely less friction in ground effect than rolling on the ground or skiing through the water.

My main concern, and the reason I am so fussy, is that pilots often think greater energy can be obtained from a big engine pointed up at a greater pitch angle. This is true of a rocket, and to a lesser extent of a F-16. Safety is often compromised, however, trying to use a Maule Rocket like a ICBM or even a F-16 (more rocket than airplane.)

The guy in this video is proving it doesn't take modifications, a big engine, and early pitch up to make a very normally powered airplane STOL.

I'm not trying to be a professor or a bad ass. I have just seen a lot of dangerous maneuvering flight over the years. My concern is to do what I can to improve that situation, if possible. That is why I harp on safe maneuvering flight techniques and the use of natural energy, where available.

Best regards,

Jim

contactflying wrote:I'm not trying to be a professor or a bad ass. I have just seen a lot of dangerous maneuvering flight over the years. My concern is to do what I can to improve that situation, if possible. That is why I harp on safe maneuvering flight techniques and the use of natural energy, where available.

Best regards,

Jim

Loved your book by the way!

It's not just the plane it's the pilot!!

Ha Ha.... STOL Cherokee? Be like flying a Mooney in the dirt.

Oh, wait...............

Gump

The lesser the capabilities of the airplane, the greater need be the capabilities of the pilot. And the more natural energy he need find. It is difficult, if not impossible, to train for maneuvering flight in a totally contact environment with a very powerful and overly complex airplane. A Mooney, by the way, is not overly complex. Really slick and fast, however. So is a Luscombe.

contactflying wrote:TxKiger,

Regardless of engine or any modifications, it is critical to understand that the technique here gave him the great performance. All landings and all but the one takeoff used the maximum (lowest) ground effect available. On landing the extra kinetic energy created by ground effect allowed a slower than Vso speed at touchdown. On all takeoffs except the one where he stayed on the ground until he pitched up to Vx, he got first the nose wheel and then the mains off in slower than Vso flight. He then immediately pitched down to stay in as low as possible ground effect until maximum kinetic energy of pressure airspeed was created on the lifting surfaces before pitching up to Vx. This extra energy was used to zoom up over a fictional obstruction.

The Cherokee, while short winged and heavy for the 0-320, can take better advantage of low ground effect than a high winged airplane. Another advantage is that you have a wing to absorb energy in a crash before your body comes to a stop. But few, other than crop dusters, consider that advantage. You also can see much better in a turn.

Best regards,

Jim

Great advice .... I've got a small to me 2,300 foot grass runway that I typically fly out of. I'll probably take the ol' cherokee over to the 6,000 foot executive runway to practice some of the techniques that the pilot demonstrates.

52Romeo wrote:hey Tx when you find out about that stol kit..you mite want to get ahold of this guy on https://www.youtube.com/watch?v=MQ1TzRrXDxo
looks like he can use some help with that Dang turbulence....or it could at least help that poor girl in the back seat...

made me lol

SA Maule wrote: it will go anywhere a high wing 182, 206 will go and out perform them in the process

Except over tall bushes and fence posts.