Wheelies

[tshort]

Finishing up the TW endorsement with my CFI.
Yesterday we went to a nearby "big" runway and did some ground handling exercises - fast taxi down the runway with the tail in the air "changing lanes", flying final at 100mph with flaps up then keeping the plane a foot or so off the runway in the flare for as long as it took to slow down, etc. Then did a couple of wheel landings which were acceptable. Winds were 4-5kts or so across the rwy. This stuff was fun and I felt like I was doing well.
After flying elsewhere for cheap gas, we returned home, where the winds had picked up to 210@15-20kt (landing on rwy 15). I planned to 3 point, as that is what I am most comfortable with ... this was my first truly crappy landing, and I made a go around with no difficulty and got er done the next time although it wasn't real pretty.
My question for you guys is, how the heck do you wheel land when the plane is bucking all over the place on final with all kinds of up and down drafts even down to the runway? My limited experience with wheelies seems like it takes a pretty light touch and you better not touch down with much rate of descent or you'll be bouncing. In yesterday's conditions, with gusty winds, the plane was up and down and I don't know if I could have planted it gently on the upwind wheel.
Any thoughts?

Thomas

[cessna170bdriver]

Thomas,

I'm not an instructor, but here's what works for me.

To handle the ups and downs you're talking about, try to compensate with power in addition to elevator. That will keep the speed excursions down. Try to FLY the airplane onto the runway, one wheel at a time if necessary. Once you have the first or both mains on the runway, you can "pin" the airplane down with elevator. Also, in a cross wind, once you get the upwind main on the ground and the airplane begins to slow, keep rolling aileron into the wind to keep the other wheel just off the ground. By the time the downwind wheel touches, you'll have full aileron into the wind, which will make it MUCH easier to maintain directional control. (I start a crosswind takeoff with FULL aileron into the wind.) In a wheel landing, I also try to hold the tail up until it comes down on its own, then full aft stick to hold it down.

I had the hardest time with the technique of "pinning" the mains on. It is very counter-intuitive to push the elevator forward with the mains on the ground in a level attitude. I had owned my airplane 9 or 10 years when an instructor suggested that on wheel landings, roll in about a half turn of nose-down trim from the hands-off setting. That way when you touch, you can just relax back pressure to pin the airplane on rather than acutally pushing on the elevator. Once you get the picture, you won't need the nose-down trim to fool yourself. It might also help to sit in the airplane on the ground with the prop at 6/12 o'clock and have someone you trust lift the tail and demonstrate just how nose down you can get before a prop strike would occur.

Hope this helps, Miles

[GAHorn]

You may not have bothered to obtain the certification, Miles.... but you are most certainly a good instructor!
I would only add that it actually stabilizes the airplane (compared to all that airborne "bucking") when the mains contact the ground with forward "stick" simultaneously applied. (Mother Earth stops the vertical movement of the airplane.)
While putting the upwind wheel onto the pavement before planting the downwind wheel is what we all learned in tricycle school..... it's not always necessary to do that in tailwheel airplanes. One of the lessons learned in flying the airplane down the runway a foot above the pavement is, that the airplane can be made to track the runway (for short periods) in a forward slip with the wings level. When that technique is developed, it's a simple matter to put the mains onto the pavement and stick 'em there with forward yoke movement. The forward elevator trim is helpful as a reminder and in giving an "assist".

(But that's not to suggest that putting the upwind wheel on first is not preferred. I just wanted to explain that with practice, it can be done the other way too...and that sometimes that's what I prefer.)

[cessna170bdriver]

One of the lessons learned in flying the airplane down the runway a foot above the pavement is, that the airplane can be made to track the runway (for short periods) in a forward slip with the wings level. When that technique is developed, it's a simple matter to put the mains onto the pavement and stick 'em there with forward yoke movement.

Educate me once again on the terminology George. In a "forward slip" as you refer to it here, is the airplane aligned with the direction of flight? If not... y'all be careful out there!

Miles

[Romeo Tango]

Miles - I am a CFI and would not say it much differently, good job!

I would add that power is the real source of "power" in this situation. You can modulate the airplane all the way down to the runway with the throttle, basically getting the vertical speed to nil if you wish. It's not much different than a soft field landing. Remember that "touch of power over the fence"? It has nothing to do with a 'touch of power' or the fence, and everything to do with minimizing the vertical velocity - the secret to a great wheel landing.

Try it sometime, adjust power as you need to helicopter the plane down to a smooth landing. Most folks land with their hand (properly) on the throttle, but aren't ready to make power adjustments on final.

The ultimate test & understanding of the airplane is when you can lower the upwind wheel to the runway and hold it on one wheel, then lift off again and pin the downwind wheel and hold it on, and repeat a few times. This should be done with someone who *really* knows the airplane, and in light winds - and will demonstrate mastery when you see it done (or do it yourself).

btw
Side Slip is the landing slip with the airplane pointed down the tarmac
Forward Slip is the altitude loss slip
Freudian slip is landing on 13 when you meant to land on 24

[cessna170bdriver]

Side Slip is the landing slip with the airplane pointed down the tarmac
Forward Slip is the altitude loss slip
Freudian slip is landing on 13 when you meant to land on 24

Those are going into my "keeper" file!

Miles

[GAHorn]

Quite right, Richard and Miles. Traditionally the "forward" slip is a term used to describe an altitude-loss manuever, while the "side" slip is used to describe the exact same manuever with the purpose of keeping an airplane longitudinally aligned with a runway. Aerodynamically they are the same, of course, but the forward slip is without regard to runway alignment. I used the incorrect term. (Just goes to show, Miles, that certification/job description doesn't necessarily make a good instructor.)
Thanks for the correction.

[cessna170bdriver]

I guess the reason I've always had a problem remembering which is which, is that the terminology seems backward to me. Back when I flew a Cub or Stearman and slipped it down final, I was looking out the "side" of the airplane. When aligning the airplane in the flare with rudder, and a little roll into the wind to stop the drift, I'm looking "forward". In any case, remembering the terminology isn't as important as knowing what works in a given situation.

Miles

[GAHorn]

A forward slip, followed by a sideslip with a left crosswind. (camera mounted on landing gear.)

http://www.bowersflybaby.com/slip.mpg

[lowNslow]

One of the lessons learned in flying the airplane down the runway a foot above the pavement is, that the airplane can be made to track the runway (for short periods) in a forward slip with the wings level.

OK George, now you have me totally confused. Are we talking about a forward slip, side slip, skid (wings level w/ rudder) or a crab ( wings level w/o rudder)???

[Joe Moilanen]

OK George, now you have me totally confused. Are we talking about a forward slip, side slip, skid (wings level w/ rudder) or a crab ( wings level w/o rudder)??? [/quote]

Had me confused too... forward or side, how do you slip with level wings????

Joe

[alaskan99669]

Had me confused too... forward or side, how do you slip with level wings????

Joe

Like George said, you can side slip "for a short period of time" wings level. Just use opposite rudder. Just like flying cross-country 'hands off', when a wing drops from a little turbulence, just step on the high wing to level it out.

Thomas, I was doing the same last week. Winds 9 gusting to 19 at a 60 degree angle. The real problem was the wind was coming over a hill and rolling across the runway. I flew the pattern for an hour for practice and in the beginning would go-around 4 of the 5 approaches. Near the end I was landing half of them. It was a lot of fun!

[tshort]

Same deal here - there are lots of obstructions at the end of this runway that produce some interesting wind currents and up/downdrafts.

So were you doing wheel or 3-point landings??

Thomas

[alaskan99669]

So were you doing wheel or 3-point landings??

Thomas

By default they have to be wheel landings, well... for me. My 3-pointers are full flaps and stall speed for soft fields. In the type of winds we are talking about I have zero to 10 degrees of flaps and I add several MPH to my approach so I don't stall when the gust dies. Since I'm going a little faster at touch down (compared to calm days) that keeps my tailwheel off the ground and makes it a wheel landing every time. By the way, if I try to do a 3-pointer stall landing (in calm weather) with less than 30 degrees of flaps, my tailwheel will touch down first and it's not a very comfortable feeling. I'm sure a non-stall higher speed 3-pointer could be done, but it feels unnatural to me.

[n1410d]

I would highly recommend the book "Stick and Rudder" by Wolfgang Langewiesche.
It was written in 1944 and does an excellent job of explaining in painstaking detail about how an airplane behaves in all phases of flight (34 pages just on the moment of touchdown, 3 point and wheel.)
Since our airplanes are basically 1940's technology, the book relates well to the 170. It is still in print and sporty's as well as many other pilot shops sell it.

Patrick
170A N1410D
Grand Prairie, TX