Flaps and stalls

[sandpiper]

Since I don't carry an extra 5-10 knots and I set down on the mains and ease the nose down, I think we are saying the same thing.

[kenny d]

Runtoeat

 

We have a 550m and a 220m grass strip , i use both , I would say the shortest i have landed the ct is aprox 150m ,I use to have a Aeroprat Foxbat/Valor and could manage 100m (all with strong head wind ) the good thing about the short strip is a clear low run in , We only use it when cross winds are high , Short landings are a necessity NOT a Preference , I will try and video a short landing for you :blink:

 

 

Fast ED

 

I Viewed your video , Is the runway a road ? the last time i seen something that long it was joining Glasgow and Edinburgh

It looks like a good setup you have , most of our local strips are grass and quite short

 

Kenny d

[FastEddieB]

Since I don't carry an extra 5-10 knots and I set down on the mains and ease the nose down, I think we are saying the same thing.

 

Almost certainly.

 

I know some Cirrus drivers who could land at stall speed (59k), landing at up to 80k - and that's a huge difference in energy.

 

A couple extra knots is not the end of the world, but I do like to have a full stall landing as the goal.

[FastEddieB]

Fast ED

 

I Viewed your video , Is the runway a road ?

 

It actually began life as a dragstrip (Sugar Creek Dragstrip). The current owner has turned it into an air park (Blue Ridge Skyport - 57GA).

 

It's about 3,000' long, but can be tricky in two cases:

 

1) In a faster plane, having to clear those tall trees can leave you about 2/3 of the way down the runway before you can get the wheels planted. The upslope certainly helps, but at least one plane (a Mooney) has come to grief there. Speed control in something like a Cirrus is critical.

 

2) The tall trees on the west side of the runway can make for a roller-coaster ride if there's anything at or above about a 10k crosswind. I've diverted to nearby Copperhill airport (1A3) when it was windy. BTW, Copperhill is closer to my house and they're just now building new hangars there. I'll be moving as soon as they're completed.

 

[sandpiper]

Back to the original subject of this thread. Yesterday, at 1100 pounds, closed throttle, gradual slowdown, I got these numbers at the break:

 

Flaps 30 - 35KIAS

Flaps 40 - 32 KIAS

[opticsguy]

40 flaps seems to give a steeper angle, which may be necessary to clear obstacles. I would think tests done at altitude aren't very relevant, because ground-effect makes a huge difference with 30 and 40 degree flap settings.

 

I'm set at 11, 25, and 35

[Ed Cesnalis]

I'm set at 11, 25, and 35

 

those are the perfect settings for western US IMHO

[Mac Bowden]

I found a very good topic on a U.K. forum regarding ” landing issues” with a CTSW. Seems the opening poster has an issue with the CT stalling the stabilator at slow speed and high flap setting.

Mac

 

This comment inspired this topic:

"Following an extremely heavy landing and go-around in a CTSW a couple of years"

The CTSW is short coupled and requires care when landing.

The shortest landing I did was with 15 degrees of flap and power off, full flap leads to loss of stabilator authority and the aeroplane suddenly sinking onto the ground.

If you apply full flap you should carry some power all the way through the flare and hold off so that the slipstream enables the stabilator to hold the nose up. This means a longer landing however and negates the desired effect of having full flap.

IMHO the CTSW suffers the same problem the original Cessna Cardinal had but unlike Cessna, Flight Design did not come up with a fix.

Perhaps the CTSW should have slots in the stabilator like the Cessna Cardinal has?

The CT-LS gets over the problem above by lengthening the fuselage. This moves the stabilator further away from the wing's downwash enabling it to work without stalling.

 

 

http://forums.flyer.co.uk/viewtopic.php?f=1&t=75017

[FastEddieB]

If you apply full flap you should carry some power all the way through the flare and hold off so that the slipstream enables the stabilator to hold the nose up. This means a longer landing however and negates the desired effect of having full flap.

 

I take slight exception to the part about power necessarily resulting in longer landings.

 

On the "back side of the power curve", power actually let's you fly more slowly, and potentially land more slowly.

 

I remember teaching soft field landings in a 150. Leaving about 1,200 rpm in resulted in a much slower touchdowns than at idle, with the potential for a shorter landing.

 

Caveat: life on the back side of the power curve entails some risks. You can get so low and slow that even full power may not arrest your descent. Best to play around with this regime with an instructor until very comfortable with it.

[Roger Lee]

Hi Mac,

 

I went over to that forum and answered his post and I invited him to our forum.

 

It is operator error to me. I land in every configuration you can think of with and without power. The only problems come when you try to land too slow and you are hanging on stall or just drop it from being to slow. I do prefer power until touch and I believe it gives better and a more solid control on the rudder and stab. Now I know landings can be done different ways and each of us has a way we prefer. I was challenged a few years ago by some of our UK friends to land with power in a 300M or a 1000" strip with power. They said it couldn't be done. The stick controls the speed so just pull it back and if the speed is slow enough it will land. I can land in 300m all day long with 2800 rpm until touch and will use either 30-40 flaps. That much flap is a big air brake. I believe he should work on the landings more and not always try to land too slow.

[Runtoeat]

Totally agree with Eddie and Roger. Maintaining adequate speed either with pitch, throttle or both is the critical requirement during high flap, short field landings. I would have liked to be around and observe when you demonstrated short field landings Roger.

[josjonkers]

Landing in a 1000ft distance is pretty much standard (wiith or without some power on) and with some proficiency is quite easy to do. Of course assuming the approaches are clear without obstacles. At my home airport I typically get stopped in about 600 to 700 feet if I had to. My first taxiway turnoff to the hangar is at 1000' from the threshold and I am never using the brake to make the turn of and just let it roll around the corner and in fact add power sometimes to clear the rwy quicker. 1000' is plenty of distance for me to safely operate. (And my homebase is even at 4000 ASL!).

[Mac Bowden]

Hi fastEddieB, the comments I posted weren’t mine I was only reporting what I read! (still love you)

I agree with everything Roger has written over the last couple of years regarding carrying enough energy during the landing phase. I haven’t got a problem with the concept of some sort of instruction or conversion training before letting loose on a CT or any of the modern ‘slippery’ type aircraft. I’ve now done 450 hours over the last couple of years and the only thing I have to remember is the small area tail on the CT2K which means I have to keep an eye on the rudder at all times when on final . My plane has been all over Europe, in and out of tiny strips, grass, gravel and international airports without any issues. For landing I tend to prefer 15 degrees of flaps as my get out of jail setting even though i've tried other settings for certain strips.

I love this plane to bits.

[Runtoeat]

Mac, you make a good point. The CT2K's smaller tail was enlarged (2006 and later CT's?) to provide greater rudder authority. The fact that you're still keeping the "shiny side up" during the x-wind short field landings with your CT2K attests to your skill as a pilot. I think your last sentence sums up most of our feelings about our little CT's.

[FastEddieB]

Hi fastEddieB, the comments I posted weren’t mine I was only reporting what I read!

 

I was aware of that, but just wanted to clarify that power left on does not necessarily mean faster landing speed or more runway. But in most cases it will, unless being used as a specific technique for a slow, nose high touchdown.

 

(still love you)

 

[Mac Bowden]

Eddie I'm a MILLER man.

If I had just done a long flight all day without water and the air temperature was about 90 and the back of my throat was covered in dust and I was celebrating a particularly smooth landing and the bar was closed for the rest of the day you just might tempt me with a BUD. Thanks in advance for the offer.

Mac

[knolde]

Looks like 40 flaps is too large a wind brake and results in too much loss in lift in the rear of the wing. 40 flaps is still ok to use, but beware and don't do full stall landings here. One little mistake or issue and you may have a very unhappy landing. I believe 40 flaps is ok to land with just use common since and keep the speed up a little more. It also looks like 30 flaps for the SW is a better choice for the controlled short field landing, offering a little more forgiveness and a little slower speed.

Looks like I'm going to reduce my flap settings to 15, 25, 35

[knolde]

Roger etal: I have an LS so all I get is 35 degrees of flap, however I also went out an played around with the flap settings for 30 and 35. I think it was the Monkeys who had the hit "im a Believer" and damned if the airplane didn't stall at a knot or two higher at 35 vice 30. I also found that the warning, buffet and stall were "faster." Although I was anticipating the stalls, it seemed that the stall with 35 degrees of flap was a surprise; I had no recovery problems nor did the airplane do anything strange or weird. With 35 degrees of flap speed control was significantly more difficult as A/S bled off very rapidly--though that might have been me as I do not normally use 35 flaps, but I did find tht there is difference.

 

With almost 500 hours in the LS and I use 15 degres a bout half the time with 55-65 Kts over the numbers depending on the wind. When I use 30 degrees I shoot for 48-50 Kts--you can color me a woosie, but the plane seems to me to be effected enough by winds to play around much closer to stall. I can easily operate from a 1500' strip (and have) and I agree with Roger that if I am at 2800 rpm over the numbers, the LA will stop in 500-700' on concrete and less in the grass.

 

Nancy and I are again planning to attend the Page flyin again this year. The Sebring EXPO was more fun this year because there were a few more venders there and we met several folks we met online after they read one or more of my articles (Decision to buy the CTLS and LSA Cross Country); this was a unique experience for me. We plan to go to Sun-N-Fun and possibly the Bahamas. Page and points West later.

 

See ya, Ken and Nancy K840KN

[knolde]

Food for thought,

 

I went out today and did a bunch of stalls. It was posted that you loose some of the stall speed advantage if you go from 30 to 40 flaps. In other words does the stall speed increase when you switch from 30 to 40 flaps. The answer for me was, Yes.

With 30 flaps my plane stalled around 36-38. When I used 40 flaps the stall speed went up4-5 knots. If you landed the same at 40 as you would at 30 and at full stall you could get in trouble quickly if something changed ever so slightly (i.e. wind change or human error, nobody's perfect ) and you were hanging on stall for 30 and was using 40. I never land near stall so it isn't an issue for me, but some of you do. One little miscalculation at 40 flaps at a full stall landing and it will be ouch time.

Some CFI's like to train using 30-40 flaps all the time and land at stall. For me this carries too many inherent risk and there really isn't a real need for it for the every day normal landing.

[Mick]

Stall speed, 30 deg. vs. 40 deg. We see indicated A/S, not true A/S. The higher angle of attack at 40 deg flaps could make a big difference because of reduced dynamic pressure (airflow) into the pitot tube. GPS speed comparison could change the result.