sensei

I can't speak for anyone else but I don't allow my R/C airplanes to stall on landing either, wheel or 3 point I fly them all the way to touchdown, but never a stall.

Bob

bogbeagle

+ 1

Quikturn

My Feedback: (12)

I think everyone's trying to say the same thing but I'm not sure stall is the best choice of words. A stall is when lift is destroyed by exceeding the critical angle of attack. When landing we round out/flair for a nose high pitch attitude but not exceeding critical angle of attack. Then, as the speed bleeds off the wing is able to carry less weight and the airplane settles on the ground.

Sgt. Meyer

Each of these arguments about stall/no stall contains some truth. Fact is, a pilot doing his primary instruction or just now checking out in a tail dragger will be taught a "full stall landing" as well as a "wheel landing." I got my Private Pilot Certificate in a Champ, and I have flown many types of tail draggers from my old 1941 J-3 through a SNJ (Navy version of a T-6) to a DC-3. I have instructed in Cessna tail draggers and in an early Citabria.

The three-point "full stall landing" is the NORMAL landing in a LIGHT tail dragger. As someone has said, it is a matter of precise timing and coordination of attitude, speed and flair to touchdown. You can feel the pressure on the stick let go just as you touch down. The airplane is through flying. The stick is already back in your gut where it needs to be for taxiing (unless there are winds you need to deal with on the way to the ramp).

The wheel landing is taught for reasons previously discussed. If the winds are gusty or high, it is safer to wheel it on and drive it as it slows and the tail eventually comes down under your control. Heavier airplanes will be wheeled on because the timing of a three-point landing is more critical if not impossible to achieve. The rare three point landing in a T-6 or a DC-3 will only be attempted by some hot shot who is just showing off.

Another point: Yes, you can do a full stall landing in a (light) trike-geared airplane. For reasons previously mentioned, you don't attempt it in a heavy airplane. They are designed to be driven on at a minimum speed, but not at a stall.

Please understand, I'm not recommending one procedure over the other. I can certainly see why you might not want to attempt a stall so close to the ground. If your bird skips along as you three-point it, it's because it is not through flying yet. If it sticks the first time, you actually did stall just as you touched down.

I can't fly my own models nearly as precisely as I could a full-scale. It's all I can do to find the runway. We have less control and slower response with our hand-eye limitations than a full-scale pilot has sitting in the seat. Wheel it on if you want to. Three-point it if you can. It's all good.

Respectfully,

Steve

sensei

I have flown many full scale and R/C aircraft and what I can attest to is this; comparing full scale flying and landing traits to our R/C flying and landing traits is like comparing apples to watermelons so I don't understand why we even bring up full scale comparisons in these R/C forums.

Bob

Rosster6028

My Feedback: (57)

All,

With models, I think it depends upon the model. Take this 42% Pitts Challenger II. Completely different animal than my Ziroli warbirds and my Yak 55 Aerobat.

You cannot 3 point this thing - you have to fly it in on the mains and relatively fast, too. I've tried to 3 point it, but it always ends up bouncing, high and then you go into the porpoising act...

So this video shows how I typically land it....

http://youtu.be/rCmGDxwh1iY

sensei

Your right, all models are not equal, that challenger would land a whole lot different 8 to10 lbs. lighter, most likely 3 point as well, wing loading and Reynolds numbers at work here.

Bob

Rosster6028

My Feedback: (57)

Oh I know! If only I could find a way to get some weight out of it! The ZDZ 160 and Ignition battery are up front and no additional weight is required. I didn't build it, but the builder who did built it to last!

sensei

Just out of curiosity, what does that beautiful airplane weigh? and what is the span?

Thanks.

Bob

Sgt. Meyer

Sorry for the long-winded post. I was simply responding to somebody's claim that you Never stall an airplane close to the ground - model Or full-scale.

I even had second thoughts before I pushed the button. Again, I apologize.

Steve.

bogbeagle

If you have 3-pointed your model, then you have landed it as slowly as is possible .... unless you try to touch-down tailwheel first.

The geometry of the undercarriage thus determines the maximum possible AoA at touchdown.

The Pitts in the video has a rather flat ground attitude, it seems to me. I would doubt that a 3-pointer would require it to be very close to its critical AoA..

sensei

No apologies needed, it's all good...

Bob

Lnewqban

I fully agree with this post.
Talking about speed of stall is not accurate.
Check this thread out:
http://www.rcuniverse.com/forum/aero...airplanes.html

The wing stalls due to excessive AOA, not because lack of speed.
Low speed means much less lift (in a square proportion), but not stall.

jerdavis

My Feedback: (3)

Stall speed is the speed at which the wing can no longer prove enough lift to support the aircraft without exceeding the stall AOA, as lift is generated by speed and AOA. Since most planes (full-sized) don't have an AOA indicator, the stall AOA is determined by the airspeed indicator reading, thus the term "stall speed".

Jerry

sensei

And that stall speed AOA is adversely effected by heavier wing loadings and of course the smaller the aircraft the less efficient the lift is because of those Reynolds numbers working against you.

Bob

MetallicaJunkie

i try not to most of the time , but sometimes on my "3d" planes i do, but i control it with throttle management

sensei

Well if you are controlling a stall condition with throttle management then your obviously burning enough gas, great job!

Bob

BMatthews

A lot of light planes don't have AoA sensors but they most definitely have stall warnings. Either stall strips that promote a lot of easy to sense buffeting a little before the stall or a stall warning alarm that can be set up to work from a number of inputs. So pilots can fly at angles either on landing or during hard G steep turns and still get warnings of approaching a stall situation.

Another little tidbit to consider. At the stall most airfoils are still producing the lift needed. But when the airflow separates from the upper surface and starts pulling a big turbulent wake behind it the wing suddenly gets as draggy as a parachute. And this sudden addition of drag along with the associated speed drop is what actually drops the lift and causes the airplane to drop away in the classic stall response.

On the other hand if we add power we can fly along in a "harrier" maneuver with the wing in a post stall situation but still making much of the lift needed to keep on flying. The rest coming from the angle of the prop thrust that helps hold up the airplane.

Our models don't seem to give us as much warning as some full size planes do. Although from flying the flat plate foamie 3D model I've got I found that this pre-stall dogginess that the full size airplanes seem to have was there to some degree. It made it easier to time a nice addition of power to transition from normal style flying to a nose high harrier without getting a nose drop or adding power too soon and having the nose rise up.

Rosster6028

My Feedback: (57)

Hi Bob,

93" Wingspan, 45# dry weight. Flies well, but you have to stay on it!

sensei

Thank you much, I just wanted the info for my own data point.

Bob

bogbeagle

Anyone have a link to information regarding the full-size Pitts as shown in the video above ... looking for span/weight and so forth.

Lnewqban

It is a Pitts S-2S Special:

http://en.wikipedia.org/wiki/Sean_D._Tucker#Accidents

http://en.wikipedia.org/wiki/Pitts_Special

http://www.airliners.net/search/phot...2800j2589534j6

Lnewqban

http://www.youtube.com/watch?v=KpIFhWYVJqE http://www.youtube.com/watch?v=hb13Q0ZmSAQ http://www.youtube.com/watch?v=IGdUA9ZKNZc

sensei

Great videos, thanks for sharing them with us. It is real easy to see many of these guys spend a great deal more time building incredible looking aircraft then burning gas flying them.

Bob

bogbeagle

OK, I used the formulae that we were discussing a couple of weeks ago.

If that Pitts is the 2-seater, its max weight is about 1700lbs.

At the given scale, it should ideally weigh 51 lbs. Buuut, it might be expected to fly better at 80lbs.

So, your 45lbs is a light-weight.