Crosswind Landings

[rudymantel]

Personally, I like to make wheel landings all the time, especially in a crosswind. I feel that I have better control. The down side is that there is a point when you are rolling on the mains when you can run out of rudder with a strong enough crosswind component and weathervane. The idea is to get the tail wheel down on the runway before this occurs.

It would be interesting to plot two lines on a graph. The left vertical axis of the graph could be air speed and the lower horizontal axis could be crosswind component. One line plotted would be the "Run out of rudder" speed. It would of course rise to the right.

The second line, which for practical purposes would be a horizontal line, is the maximum tail lowering speed that wouldn't send you back in the air. (Although aircraft weight and cg would affect this, let's keep it simple and disregard those factors.)

Where the two lines cross would be the maximum wheel landing crosswind component speed.

Any volunteers for gathering some points to plot this graph ? I look forward to your thoughts and comments on the graph or just crosswind landings in general-
Rudy

[hsjrev]

I wonder how you factor in differential braking. I was taught that being able to use your brakes for directional control after you run out of rudder was the main reason for doing wheel landings. Of course I'm pretty new to tailwheel flying so please advise me if this is way off base.

[frainiea]

I have a little data that might describe the horizontal line you defined. The connection I am making is that the air speed you reference is that at which when you pull back to plant the tail you do not come off the runway. I am not sure if this is the same air speed that the tail will fall naturally. Are two wheel landings done with and without flaps?? I am very nervous about using flaps in a cross wind landing and generally cross control all the way to a close to full stall landing. I would be interested in hearing some rpm and airspeed utilized for two wheel landings.
Getting back to the data here is what I did. I was trying to define the air speed to the descent rate to help me better approach the critical transition from the air to the ground, the flare. I collected data with power off for no flaps and twenty degrees of flaps. I also ran the experiment with no flaps and 1200 RPM of power. For each aircraft configuration I flew at different air speeds and had the co-pilot record the time to drop 1500 ft and then calculated the descent rate for each air speed. I constructed a plot with the descent rate on the vertical or Y-axis and the airspeed on the X or horizontal axis. The curves for the three cases where represented by valley shaped lines. I interpreted the minimum for each curve as the lowest airspeed point at which if I pull back a decrease air speed the descent rate would decrease. Any lower and a decrease in air speed would increase the descent rate. The results were as follows. No power and flaps the minimum was 59 MPH. No power no flaps the minimum was 64 MPH. For some reason I can not explain the no flap 1200-rpm case the minimum number was even higher, at 70 MPH. The over all curve or valley shape of the 1200 rpm case was much flatter as I expected which says to me that I can control the flare more easily with 1200 rpm. I have not adopted a 1200-rpm technique. The old adage is you may not have the power someday and you better practice what you can count on.
My assumption is that if you pull back on the yoke, air speed will go down and the plane will rise if you execute the maneuver above the minimums from the data. This is the opposite of what should happen when you plant the tail wheel.
For my approaches with no power and no flaps I use 70 MPH on approach with confidence that a slight pull on the yoke will give me a flare with a decrease in descent rate. Again my assumption is that the tail is going down relative to the plane and there is more lift even at the lower airspeed so I get a nice soft landing.
So if I am below the minimum the tail would go down and the plane would remain on the ground.

[zero.one.victor]

Differential braking is available as soon as the mains are on the ground good and solid,long before the tail can come down without flying off. You can really come on with the brakes,differentially as needed,using the brakes to keep the tail up instead of the elevator. You can keep the tail from coming up too much with the elevator. It's hard to explain,the best explanation I've seen is the article by Bill hite on the skywagon.org site.There was a link to it posted here recently. Good reading,even if you don't believe in wheel landings.
There was also 2 good articles about this subject in The 170 News a few years ago--"the great wheel landing debate parts 1 & 2"

Eric

[N1478D]

Have been in the habit of doing wheel landings on pavement, especially in crosswinds, and 3 pointers on non-pavement. BUT, going to change that and do wheel landings everywhere after the tailspring broke landing on turf in a three pointer with a little weight in the rear. ( There was a rust spot with stress fractures radiating out from the rust spot hidden underneath the paint on the spring so it would have broke eventually somewhere if not detected.) A wheel landing allows you to control when the weight goes on the tail, even on a bumpy surface, and the tail has to be one of the weakest parts of the airframe. In a crosswind a wheel landing allows you to get one wheel down and gather control and track straight before you allow the other wheel to come down.

After this annual is complete going to go out and practice wheel landings on rough terrain for a while, should be fun. Like that referenced article stated, if speed is managed you do not have to stick it on with forward pressure, you just touch the wheel down. On rough terrain it is going to be interesting seeing what it takes to keep it from bouncing up off of a rough spot.

[Tom Downey]

In other words you want to trade maybe tail wheel spring damage, for certain gear box damage.

[zero.one.victor]

Joe,you're probably safe for a few years from breakage with your new tail spring(s). But it's probably best to be proficient at both wheelers & 3-pointers. I usually wheel it onto pavement & stall it onto grass,like you said,but have 3 pointed onto pavement & wheeled it onto grass,too. Just be careful wheel landing onto soft fields. A boggy old mudhole could be a real disaster.
I usually do my wheel landings with a tail low attitude. I've seen some people land & roll out with the tail so high it scared ME,and I wasn't even aboard!
Tom,are you saying wheel landings will cause gearbox damage? The gearbox damage I've seen and/or heard about was generally caused by going sideways--ie,ground-looping. If you hit hard enough to hurt the gearbox in any kind of landing,you're doing something wrong.

Eric

[N1478D]

Good Morning Tom & Eric,

Tom, I was planning on starting out on a nice smooth grass strip and practice wheel landings. Since I started out doing wheel landings and 99% of my landings are wheel, unless I practice a 3 pointer on concrete, I've enjoyed the 3 pointers on grass. It became a habit over time to do 3 pointers on grass. So, didn't mean to imply that I was going to go out and search for a boulder strewn strip and knock the landing gear off. But, it was an undulating grass strip on a windy day when the tailspring broke. It was smooth enough for a wheel landing, but out of habit, I did a 3 pointer and a wheel landing that day might have been a better choice. After some practice on smooth grass I will move to an undulating strip and practice holding the tail up as the strip goes up and down. Tom, thanks again for your recommendation on the Rudder Skins. Karl's work is very very good.

Eric, you sure are right about soft fields and high tail landings. My wheel landings have the tail lower than level flight attitude too. Have not seen very many people landing with their tail real high except during their initial training. About 5 years ago my instructor demonstrated how he could hold the tail up all the way thru landing, slow taxi turns off of the runway, and then to parking. I enjoy not letting the tailwheel touch the ground every once in a while doing touch and go's but have not attempted it all the way to parking.

[zero.one.victor]

That tail-high taxiing is a cute trick but fits into the "show-off" category as far as I'm concerned. Unless it's part of their airshow routine,why would a person need to do that? If the tailwheel broke off,stop,park,and fix it. Limited use of the stob of a tailspring for a tailskid shouldn't damage anything,just cut the steering chains to remove the dangling tailwheel assembly to avoid (further) rudder damage--guess you could tell us more about that,Joe.
If a person enjoys showboating like that,goody for them,but it doesn't reflect well on them.What other show-offy stuff will they do? Remember the 3 most dangerous words in aviation--"hey,watch this!"

Eric

[frainiea]

How about some specifics on how to set up and execute a wheel landing

[zero.one.victor]

Read the article by Bill White about wheel landing a 180,it's just as applicable to 170's. Go to http://www.skywagon.org,click on "knowledge base",then click on the article. Someone posted a link direct to this article not too long ago on one of the forums.

Eric

[hsjrev]

http://www.skywagon.org/content/kbase/c ... ndings.htm

[zero.one.victor]

http://www.skywagon.org/content/kbase/c ... ndings.htm

I wanted to put this on the "links" page of the Association site but didn't see how to do that. Anybody know how? Or is it a webmaster show?

Eric

[zero.one.victor]

I'd also like to add links to the http://www.skywagon.org site,as well as the 120-140 Club's site (http://www.cessna120-140.org). A lot of good information there,both on flying these Cessna taildraggers as well as maintaining them. After all,these airplanes are our 170's closest relatives--parents & offspring!

Eric

[flyguy]

ERIC WROTE: That tail-high taxiing is a cute trick but fits into the "show-off" category as far as I'm concerned. Unless it's part of their airshow routine,why would a person need to do that? If the tailwheel broke off,stop,park,and fix it. Limited use of the stob of a tailspring for a tailskid shouldn't damage anything,just cut the steering chains to remove the dangling tailwheel assembly to avoid (further) rudder damage--guess you could tell us more about that,Joe.
If a person enjoys showboating like that,goody for them,but it doesn't reflect well on them.What other show-offy stuff will they do - - - - - - - - - -

OLE GAR WRITES, WELL LES SEE - - - - NAH AINT GOIN THERE - - - BUT

I LANDED (WHEEL LANDING OF COURSE) AT OSHKOSH SEVERAL YEARS AGO AND TURNED OFF AT THE APPROPRIATE TAXIWAY STILL TAIL HIGH. THE CONTROLLER CAME ON THE FREQ AND SAID "SILVER 170, YOU CAN DROP YOUR TAIL NOW AND FOLLOW THE WHITE AND BLUE 170 TO THE CLASSIC PARKING AREA WITH THOSE OTHER SHOW OFFS".