Calculating app. speeds in gusty conditions

[piperboy84]

A question about approach speeds, my aircrafts published stall speeds are as follows:
VSO 47MPH/VS1 61mph at a gross weight of 2400LBS.
For the most part I fly by myself with half tanks which adds up to appx.

Aircraft empty weight 1440
½ tanks 36USG 216
Me 204
Total 1860 LBS

On short final approach with full 48deg flaps (flap settings are -7Deg Cruise, 0Deg Cruise, 24Deg Take Off, 40 Deg land, 48deg land) I give myself an approach speed of 55MPH (VSo 47mph x 1.3= 61 mph, –6mph for being under gross weight calculated at 1MPH for each 80lbs under gross appx.)

In strong gusty conditions the manual “suggests” that zero or negative 7 deg flaps “may” be used, which using the figures above translates to an approach speed of 73MPH which is way too fast for my liking in those conditions as a low time tail dragger pilot, so I avoid flying in strong gusts.

However, an approach where it is moderately gusty I prefer to come in and land with 24 deg which I feel is a compromise (the 40 + 48 deg flap is like throwing out a barn door, not sure about lift component at these settings but there is a ton of drag).

Based on the above scenario of the airplane configured with 24deg flaps during a moderately gusty landing is there a method to calculate what my exact approach speed should be based on the weights listed above or do I just pick a number halfway between the weight adjusted approach speeds (VS1 55mph + VS0 73mph)

Or on the other hand, am I thinking too much about this one !!

[Jan Olieslagers]

Not speaking from my own wisdom, but rather from what I remember from the words - in various degrees of frustration - from several tutors, I do think you are too much focusing on the numbers/figures.

The formulae, like 1,3 times stall speed and what not, may be most useful when flying a type one is not familiar with. (There's a couple of test pilots around and I am curious to read their opinion!) But I was taught the real art is to hear and feel and understand what the aircraft is telling you directly. Especially as you fly your own dear and sweet, you might perhaps do worse than to take a couple of flights with an instructor, familiar with the type if possible, and have the plane flown to its limits, and make you feel those limits.

I was recently given such a lesson, unrequested and unexpected, and it was quite an eye-opener. The main thing I learned was, of course, there are still SO many things I need to learn.

Or, in other words, suppose you get through all this stuff and store in the back of your head a perfect table of what IAS to fly at which combination of QNH/wind/gusts/altitude/&c/&c (quite an achievement, that would be!), what good will it do you when the ASI gives up?

[Genghis the Engineer]

Personally, in most conventional aeroplanes, I have come to the conclusion that it is inappropriate to modify the approach speed for an approach in gusty conditions. If you work through the maths, approaching faster, only increases the gust response.

But, it is appropriate to approach with a bit less flap, so long as there's enough runway - which in strong winds, there generally is.

With less flap, stall speed goes up, and so should approach speed. Both go - at first approximation anyhow - with the square root of mass.

I can only think of one aeroplane I've flown with negative flaps, and it's not got an MTOW of 2400 lb (plus the training wheel is at the wrong end), so I'm not sure what type you're referring to. However, in general terms, flying a negative flap approach sounds like a bit overkill. However, let's look at the zero flap condition.

If VS1=55mph is the MTOW stall speed with zero flap, and you're approaching at 1860lb, then my first stab at an appropriate approach speed would be:

55 x 1.3 x SQRT(1860/2400) = 63mph.

Which intuitively feels about right.


I think you've got the right general idea, it's just a case of getting the numbers right.

One caution, at very high flap settings and low speeds ASIs tend to underread, if the approach speed is much more than 30% above the stall speed, factor the approach speed, not the stall speed - which may give you a dangerously low approach speed.

In a taildragger, I'd also in those sort of conditions seriously consider flying a wheeler landing rather than a 3-pointer as well.

G

[piperboy84]

GET,

In a taildragger, I'd also in those sort of conditions seriously consider flying a wheeler landing rather than a 3-pointer as well.

I know I may get crucified for saying this but when I flew with Ray Maule during the purchase checkride for my Maule Mx7-180a he very strongly advised against "wheeler" landings in this plane regardless of what the conditions were.

Another point, is is it possible that the 40 and 48 degree setting afford very little lift and extremely high drag so even if I only have 24 deg (take off setting) deployed on landing I should expect VS0 performance speeds even with the final 2 notches of 40 + 48 flaps not being deployed

[Genghis the Engineer]

I've not flown a Maule, and only have about 250 hours in tailraggers, so Mr Maule may have the advantage of me, but myself, I think you aren't competent in any taildragger until you are fluent in both 3-point and wheeler landings in it.

The issue for me here is neither lift nor drag, but lift curve slope. Flaps increase the lift curve slope, which increases the gust response in turbulence. Hence that lower flaps should work better - and if it's windy enough to need this, usually you have more than enough runway to land with a higher approach speed.

G

[Chuck Ellsworth]

I've not flown a Maule, and only have about 250 hours in tailraggers, so Mr Maule may have the advantage of me, but myself, I think you aren't competent in any taildragger until you are fluent in both 3-point and wheeler landings in it.


I have never flown a tail wheel airplane that could not be wheel landed.

I would never check out any pilot in a tail wheel airplane unless said pilot was competent in both wheel landings and three point landings.

Myself I prefer the wheel landing almost all the time.

As to approach speeds in gusty conditions if you have to add airspeed to the normal airspeed you use trust me using math to figure out you need 63 MPH or what ever is over kill because no one I have ever met can fly that accurate an airspeed.....hell the needle is to wide to be that accurate. :ugh:

[piperboy84]

Chuck


I am not saying the Maule cannot do a wheeler landing , merely that Mr Maule and many Maule pilots I have talked to feel that the Maule is more suited to a 3 pointer in cross winds and based on my limited experience I would agree with them. I’m an extremely low time TW pilot, my total TW experience since buying the Maule a few years ago was basically jumping in it and trying to self teach for the first 100 or so hours then getting at total of 25 dual TW instruction/endorsement in a Maule where I demonstrated wheeler landings to the satisfaction of the CFI. I can and do practice them regularly on no wind days on long tar runways, but I am not comfortable doing them on my short, rough grass strip that often has surface water.

Regarding the approach speeds, I guess I made a dogs dinner of explaining my question, what I am trying to get to the bottom of is given that it is advisable not to use full flaps in a gusty wind and that I have a feeling that the final 2 notches 40 + 48d feel that they provide significantly more drag but no noticeable lift can I assume that the published VS0 speed remains the same pretty much from 24d (TO setting)thru 48d (full flaps)

[Genghis the Engineer]

Stall speed with flap setting varies with type.

The first way to answer the question is look in the manual. The second way is to go up to a safe height and try. Given you should stay comfortable with all the main stalls in your aeroplane anyhow, if you're not already doing that - you should.

I tend to prefer a 3-pointer, but otherwise agree completely with Chuck.

G

[Maoraigh1]

Apart from the manual and the wind, consider the terrain. If approaching a strip near the top of a hill, you can have a lot of wind shear + downdraft. Consider what your ground speed looks like, before descending into the windshear + downdraft zone. Also consider tree effects. I don't think there's a mathematical formula for light aircraft on non-standard airfields.

[robin]

Quote:
I've not flown a Maule, and only have about 250 hours in tailraggers, so Mr Maule may have the advantage of me, but myself, I think you aren't competent in any taildragger until you are fluent in both 3-point and wheeler landings in it.
I have never flown a tail wheel airplane that could not be wheel landed.

I would never check out any pilot in a tail wheel airplane unless said pilot was competent in both wheel landings and three point landings.


Not sure I would agree with that. There are some types that are better landed 3 point or tailwheel first. I'd never think of using a wheeler for my Jodel or Cub. Others might be different though

[Genghis the Engineer]

Super Cub lands fine with a wheeler.

My point is however, that a tailwheel pilot should be competent in both, then THEY get to choose which method they use. If they can't do both, then their training is incomplete and they are naturally limited.

G

[Chuck Ellsworth]

I am not saying the Maule cannot do a wheeler landing , merely that Mr Maule and many Maule pilots I have talked to feel that the Maule is more suited to a 3 pointer in cross winds and based on my limited experience I would agree with them

Piperboy84, first let me say I have not spent much time on Pprune for the past two years due to unforeseen circumstances in my life....

.....however I probably will post more often now that things are getting sorted out for me.

Also I will do my best to stay away from confrontation and also allowing emotion to override common sense and facts in my replies.

Now back to your comment above.

What exactly is it about the design of the Maule that would invoke such a comment from pilots familiar with that airplane?

I have searched my memory banks and I can only remember ever flying two Maules in my life time, both were on amphibious floats and one had a piston engine and the other had a turbine in it.

I do not recall anything about the piston engine one as far as flight control response that would affect the landing attitude one chose to use.

For sure aircraft types can make them easier to land in the fly it on method called the wheel landing than trying to three point them the Beech 18 comes to mind and the reason it was easier to wheel land it rather than three point it was due to the design of the airplane the rudders had degraded effectiveness in the three point high alfa flight range making for tricky directional control compared to wheeling it on...

....conversely the Pitts tends to be easier to three point due to restricted forward vision in the thing during the landing flare portion of the flight.

My preference for wheel landings are more effective control response at touch down.......and that is why I prefer to wheel em on....all except the Pitts. :E

I fly a Husky for a friend and when it was on wheels I found it wheel landed every bit as easy as a Cub. :ok:

Especially in strong x/winds. :ok:

[taybird]

Some taildraggers (exceptional) exhibit a strong preference for one type of landing or the other. For example a DC3 is normally wheeled on. I understand the same is true for the T6. Other aeroplanes don't tend to like being wheeled on such as Pitts S1, for example.

But in most cases, in my experience, both are possible. I agree with GtE on this - the option to use a wheeler landing made my life a whole lot easier when landing in 15G28KT conditions with additional turbulence from trees. Out of interest, I added around 10mph to my normal approach speed from 60mph to 70mph. This smoothed out some of the lumps, making the sink bits less painful and giving me just that little bit extra control authority. I was still stopped, no brakes, in a couple of hundred metres from the runway threshold. Worked for me, but then I know that aeroplane reasonably well, and had practiced lots of wheelers. Incidentally the type doesn't wheel as nicely as some others, and is much happier when 3pointed. But in this case the wheeler was hands down the best way to do things.

Fly to the conditions. Know your aeroplane and how it responds in slow flight. Then it'll tell you if you're getting too slow, and it'll tell you when you have things about right. Just IMHO.

[Chuck Ellsworth]

The question of which method will produce the shortest landing is also an interesting one.

Anyone remember watching the guys in Alaska competing for the shortest landings in Super Cubs?

Did they three point them or wheel land them?

How to fly tail wheel airplanes always ends up to be really interesting reading on these forums.

Pilot DAR was here yesterday he stayed overnight with me talking about airplanes and stuff and one of the conversations got around to the DC3 and how it three points.

Actually the DC3 will three point quite nicely....but you have to be really careful judging your height above the runway before it stalls. :E

[piperboy84]

Chuck,

Well done getting thru whatever it was you had going on.

I cant speak for why Mr Maule and several guys on the Maule forum who specify 3 pointers as opposed to wheelers but from a personal perspective I would like to throw out why I assume they think this way.

Again taking into account my limited TW experience, i would greatly appreciate if you could pick apart my theory as to why i believe 3 pointers are superior over wheelers in the Maule hopefully it will be learning curve for me.

Firstly, you said

the reason it was easier to wheel land it rather than three point it was due to the design of the airplane the rudders had degraded effectiveness in the three point high alfa flight range making for tricky directional control compared to wheeling it on...

Now i understand the concept but inst this kicking the problem down the road a bit due to as you slow up your tail is still in the air as opposed to a 3P where you plant that tail hard on the deck and pin it there with full back elevator essentially trading directional control via airspeed on the rudder to control via ground friction. the principle being once authority recedes the friction takes over the directional control

Secondly, I have looked at planes of similar utility to the Maule like the Husky etc, and I think the Maule has a far larger tail side profile which in a wheel landing right at the point where the tail is about to drop you have lost significant authority and still have this large surface sitting up there which will pivot on the mains a lot easier without ground friction of a 3P, granted if the wind is strong enough to swing you round regardless of which landing method is used it will happen at a slower speed in a wheeler.

In my particular case my home strip is appx 1600ft with obstructions at both ends and in conditions where there is significant x wind I am just not comfortable holding the extra speed necessary for a wheeler

[Chuck Ellsworth]

Hi again piperboy84.

I will slice and dice all your questions and try and explain in detail why I have my opinions on how to fly airplanes....but first I would like to explain this better.


Well done getting thru whatever it was you had going on.

I lost my wife to cancer in the fall of 2010 and the process of recovering emotionally has been difficult, I met her in 1968 when I was flying a DC3 for a Canadian airline and she loved airplanes. Life has slowly improved and I am about to go back to finishing building a Cub that I was rebuilding when she got sick two years ago.

Now to your questions.


Now i understand the concept but inst this kicking the problem down the road a bit due to as you slow up your tail is still in the air as opposed to a 3P where you plant that tail hard on the deck and pin it there with full back elevator essentially trading directional control via airspeed on the rudder to control via ground friction. the principle being once authority recedes the friction takes over the directional control

The advantage to contacting the landing surface in the tail up wheel landing attitude is you have far more flight control effectiveness to deal with any excursion in direction or attitude that may be present at the point of ground contact and if the excursion is serious enough you are still in the flying attitude and can reject the landing with take off power and go around and try again.

In the tail up wheel landing attitude the progression from using the flight controls to maintain your direction and attitude can be more effectively transferred from aerodynamic control from the flight controls to ground friction on the wheels by reducing lift from the wings to the wheels by changing angle of attack with the elevators......lowering the nose...

The transfer to the tail down attitude can now be easier controlled because you have better directional control if needed because more weight is now on the wheels and brakes can be more effective because the weight is now on the wheels.....therefore better traction for braking if needed.


Secondly, I have looked at planes of similar utility to the Maule like the Husky etc, and I think the Maule has a far larger tail side profile which in a wheel landing right at the point where the tail is about to drop you have lost significant authority and still have this large surface sitting up there which will pivot on the mains a lot easier without ground friction of a 3P, granted if the wind is strong enough to swing you round regardless of which landing method is used it will happen at a slower speed in a wheeler.

Go back and read my last comments and it will reinforce why I have my opinions on how to best fly tail wheel airplanes.....of course there are exceptions to how best to land some airplanes and the Maule might have some directional problems during landing that I am not aware of.....hopefully someone here with more Maule knowledge will jump in and explain why the Maule is different from most of the light tail wheel aircraft that are common in general aviation.

There was only one airplane I can remember flying that I never had the balls to try and three point and that was the Grumman Turbo Goose....that sucker was truly a challenge directionally on the runway.


So....

All pilots who fly tail wheel airplanes """ M U S T """ be equally proficient in both methods of landing.....wheel landings and three point landings.....and everything in between.:ok:

[Proteus9]

There's a lot of talk either way about landings and you've got to find what you're comfortable with. My limited tailwheel experience is all on Huskies so that is my reference for discussion. The basic Husky "bible" by Jeff Welch advocates the 3point type landing in everything but calm conditions where a wheel landing could also be used. His line of argument is that the more excess speed you are carrying the more susceptible you are to ground looping, secondarily followed by the fact that with the tailwheel planted you get a certain amount of stability and steering assistance. I must admit I favour the 3point landings too, and certainly when bringing it down in a crosswind, I two point with tail and one main. The only thing about the three point landing that is a bit of a concern is the extra beating it applies to the tailwheel when landing on rough strips. The consensus of the online husky community seems to be that a tail low wheel landing is the best compromise on the rough stuff to protect the tail as much as possible. lifting the tail up on particularly narrow strips after landing also gives you better forward vision. Another argument against wheeling it on could be brought in if you are running big props on rough surfaces, a three pointer would help keep that clearance. The Alaskan stol competitors nearly all come in for a three pointer then slam on the anchors as hard as possible which lifts the tail. If they came in to wheel it on they'd be carrying more speed than they need to which would lead to a longer landing run. I think you just need to experiment a little where it is safe to do so and find what works best for you. I prefer just to use two stages on the Husky in a reasonable crosswind whereas some people still prefer to use full. I'm not familiar with how Maules fly, but Huskies really don't like excess speed on approach, they just float and float. Most people agree the POH figures vary between vastly too high and a bit too much depending on individual dogs. As been said before, really it helps to be reasonable at either so you can choose what you think best suits the situation.