Precision take-off and landing distances

[Chuck]

In learning to fly the CTSW I purchased last summer I've been doing a bunch of pattern work, with full stop landings and takeoffs at various flap settings.  I've been amazed at the short field capability of this aircraft, with most of my 15-flap takeoff rolls being in the 250' to 275' range with just me in the plane with average or slightly below temperatures.  When it gets a little colder up here in NH, this has come down to more like 225' and with 30-flap takeoffs I can sometimes get it down below 200' on pavement.  The grass operations I've been doing usually add 50-100' to the takeoff roll.

I'm still working on getting the landings precise and on-speed, but unless I really flub it I can usually get stopped in less than 450' with moderate braking on pavement.  Again, this goes up with grass as I can't really apply much braking without locking up the tires.  The real challenge I'm finding is precisely hitting my touchdown point.  I've been flying taildraggers exclusively before getting the CT, and with those it was possible to get low and then even if you're carrying a *little* extra speed you can inch the stick forward and drop that last foot or two to get it on the runway right where you want and start braking.  But I'm so scared of hitting my nosewheel first that I end up floating down the runway at 0.5' altitude until enough speed bleeds off to drop in.

I'm measuring all this with a fun project that I started working on during the pandemic with my friend Erik - check out www.STOLmate.com for details.  If you watch the little video I made for the website you'll catch a few seconds of footage of my CT right at the end.

 

-Chuck

STOLmate website

[Anticept]

Marc wheels or matcos?

The marc brake system is a bit better built for this. This is a drawback to matcos, they're not as robust for hard braking.

[ct9000]

if it's floating a bit with full flap you may still be a bit fast. although not my favorite method you can carrry  more power, keep the nose up then chop the power on touchdown so that you are controlling descent.with power. But I guess you already know that.

Ps I am taildragger pilot as well 

[Eddie Cesnalis]

I limit 40 degrees to calm winds.  Float and even baloon can result from light variable at 40 where 30 will sink.

[ct9000]

With respect Ed, each to their own. I always used 40 deg. The extra drag is a big help and at 40 does not contribute much lift at all.

In rough air you can use some power to help other control surfaces without eating up lots of runway. Adding power with 30 will increase landing distance a fair bit.

In my defense I almost always fly off short grass strips. 

[FlyingMonkey]

I agree with Ed and ct9000...try to approach a little slower.  For reference, with my CTSW I like 48-50kt @ 30° flaps.  I find 40° to be less forgiving without buying me much, so I still practice 40° landings but don't do them very often.

[Anticept]

One of the things taught with more extreme short field landings is combining full flaps with a little bit of power with a low slope. You'll come in carried under power, and the moment you chop, you drop. You can get really good with flaring just before the runway threshold and chopping right at the start of the runway.

This is however not safe to do in gusty winds.

[Towner]

4 hours ago, FlyingMonkey said:

I agree with Ed and ct9000...try to approach a little slower.  For reference, with my CTSW I like 48-50kt @ 30° flaps.  I find 40° to be less forgiving without buying me much, so I still practice 40° landings but don't do them very often.

X2

[FlyingMonkey]

2 hours ago, Anticept said:

One of the things taught with more extreme short field landings is combining full flaps with a little bit of power with a low slope. You'll come in carried under power, and the moment you chop, you drop. You can get really good with flaring just before the runway threshold and chopping right at the start of the runway.

This is however not safe to do in gusty winds.

I use this technique quite a bit..."dragging it in with power" is what I call it.  The only thing to be aware of doing this the first couple of times is once you pull the power out you probably have to lower the nose to keep your airspeed.

[Anticept]

You drag it in with the power until you're flared and just over the runway threshold. You will have to adjust power a little if it tries to float, but you cut it when you're ready to stick it. You will be flaring over the grass and having it hang off the prop just before the touchdown point.

[FlyingMonkey]

17 hours ago, Anticept said:

You drag it in with the power until you're flared and just over the runway threshold. You will have to adjust power a little if it tries to float, but you cut it when you're ready to stick it. You will be flaring over the grass and having it hang off the prop just before the touchdown point.

I understand what you're saying....I sometimes drag it in over trees to grass fields, then pull the power out once past the obstacles, and it comes down like an elevator, but you do need to push the nose over to keep your speed.  It all just depends on where in the landing cycle you pull the power out.  Definitely don't push the nose over in the flare unless you hate your nose gear and prop.  

[Anticept]

Yeah if you're landing over trees you have to learn to push it over.

I already push for students to learn to push the nose down even when we're getting close to the ground. One of the things I am paying attention to during landings is watching if they bleed off airspeed before the flare. It tells me they are pitching for the runway instead of changing power. That adds complications when landing. Gotta learn to pitch for the runway only once flare is reached in a standard glide.

My reasoning: your selected approach airspeeds should be held all the way up to flare in a standard glide, it demonstrates that you are keeping control of pitch and power. In a flight design, its easy to let the airspeed bleed off just before flare, and that's where I think people are getting the broken landing gear because they'll drop in like a cirrus.

[Chuck]

Lots of good suggestions here - very helpful for me as I'm transitioning from my taildragger habits.  I went out a few days ago and tried just reducing my approach speed a little bit, and it made a huge difference.  The previous owner had encouraged me to fly between 55 and 60 on the approach, but I'm finding that getting it closer to 50 on the approach and then shooting for about 45 over the fence yields a lot less float (this is all with 30 flaps). My STOLmate was measuring more like 325'-350' to get stopped on most of these.  Then I did a couple landings with 40 flaps and coming in with a little power applied, and then chopping the power right during flare and I was able to to get it down to less than 300' with moderate braking.  My shortest landing roll was measured at 270'.  I also like the power-chop landing because it made it easier to hit my aiming spot.  

 

I'm working on editing together some footage that shows split-screen of the GoPro wing footage and screen capture of the STOLmate app.  Turns out video editing is hard, but once I get it put together I'll try to figure out how to share it here.

 

Thanks for all the advice!

Chuck

[Anticept]

Just a heads up, at such low airspeeds everyone's airplane is going to read different. the important thing is if you get a stall horn or buffeting during approach, the reaction should be add power and drop the nose if able.

50-55 is the recommended approach. If you need a shorter landing distance, use a combination of keeping your slope from being too high, set your aim point in the grass before the runway (the roundout aimpoint), or use more flaps on final.

[FlyingMonkey]

Good stuff Corey, thanks!

I do find one of the main points in the "art" of CT landing is where & how to set the pitch angle in the last few feet.  You don't really "flare" a CT, it will want to balloon if you do.  Instead, you kind of set the pitch angle for touchdown and more-or-less keep it there, adding back pressure to the stick to maintain the angle as speed decays.  It's tricky because the nose wheel on landing is only a few inches above the pavement. I find two things help:

1) Wait to set the landing pitch until you're through the initial ground effect.  You'll feel the pause in descent when you hit it, just wait until the descent resumes.  Otherwise if you start raising the nose in ground effect you'll likely get the AoA too high and risk a "carrier style" landing, dropping in from a foot or two.

2) Keep the speed on the low side.  As I mentioned I like 48-50kt, but Corey's 50-55kt is fine too.  At slower speed the ground effect pause in descent will be less pronounced.  You'll have to use a little more back stick to arrest the descent, but the feel will be more progressive and the chance of ballooning or floating goes way down.

You can absolutely go into ground effect at 60kt (or 70kt, I have done that too) and land the airplane just fine, but you're probably not going to do it in the first 200ft of runway unless you're in ground effect a good distance before the pavement starts.  It just depends on the kind of landing you're doing and what the runway is like.  If all your landings are on 3000ft+ paved runways then you can "fly it on" at pretty much whatever speed you want.  But if you always want to hit the numbers, or land on a short runway or over high obstacles, then 48-55kt is going to serve you best IMO.

[Tom Baker]

A word of caution. Everyone is telling you what works for them in their airplane. I have flown a lot of different CT's, and you can't use a cookie cutter approach. The speeds may be perfect for one airplane, and the next it will be to fast or slow. 

[Tom Baker]

1 hour ago, FlyingMonkey said:

I do find one of the main points in the "art" of CT landing is where & how to set the pitch angle in the last few feet.  You don't really "flare" a CT, it will want to balloon if you do.  Instead, you kind of set the pitch angle for touchdown and more-or-less keep it there, adding back pressure to the stick to maintain the angle as speed decays.  It's tricky because the nose wheel on landing is only a few inches above the pavement.

I have a 1,000 plus hours flying and teaching in CT's. You can flare it like any other airplane. The only reason it will balloon is if you increase the pitch to much for the speed you have. Also if you are adding back pressure and decreasing speed you angle of attack is changing. If you don't change the angle the airplane won't decrease speed.

With all landings you have to decrease speed. I tend to wait until I am closer to the landing point to start the decrease. I will fly 60 on approach, and start changing pitch to slow down at around 50 feet. From there it is a gradual change in pitch all of the way to touchdown. I haven't been flying a CT as much lately, but when I am in practice I can pretty much touch down within 100 feet of my chosen point right at stall speed. The reason I fly the approach a little faster is that if you lose power you will be more likely to make the runway than if you are at the slower approach speed, especially if you have some headwind.

 

[Madhatter]

On 1/20/2023 at 11:56 AM, Anticept said:

Yeah if you're landing over trees you have to learn to push it over.

I already push for students to learn to push the nose down even when we're getting close to the ground. One of the things I am paying attention to during landings is watching if they bleed off airspeed before the flare. It tells me they are pitching for the runway instead of changing power. That adds complications when landing. Gotta learn to pitch for the runway only once flare is reached in a standard glide.

My reasoning: your selected approach airspeeds should be held all the way up to flare in a standard glide, it demonstrates that you are keeping control of pitch and power. In a flight design, its easy to let the airspeed bleed off just before flare, and that's where I think people are getting the broken landing gear because they'll drop in like a cirrus.

The CT drops because the tail stalls due to boundry layer separation caused by airflow turbulence above the cabin during flare. That in turn stalls the wing. This is an issue on all CT's except the F2 which was wind tunnel tested and designed. I have  the video of this occurring on my CT. That is why you can't prolong the flare in a CT.

[Towner]

Be careful when trying different techniques. Mine had a couple scuffs on the fin from light tail strikes on landing. I had also talked with the local Sheriff’s office, who had an LS for a few years. They said they also had a few tail strikes. I haven’t had one yet, but I see how it can happen.

[Eddie Cesnalis]

I tend to find 62knots abeam the numbers and get my landing flaps there.  Once I have them (30 or 40) I will fly often fly well into the white arc until I'm pitching for touchdown and then I want the full flare so my balance on my mains is good and I dont' tip onto my nosewheel right away.

Speed decays quite quickly at 30 or 40 so using the entire white arc gives me the more stable feel when I want it and the slow/short rollout.  In my head I feel like I'm keeping my nose low enough to load up my flaps.

[Tom Baker]

33 minutes ago, Madhatter said:

The CT drops because the tail stalls due to boundry layer separation caused by airflow turbulence above the cabin during flare. That in turn stalls the wing. This is an issue on all CT's except the F2 which was wind tunnel tested and designed. I have  the video of this occurring on my CT. That is why you can't prolong the flare in a CT.

The CTSW was wind tunnel tested after the fact, which led to the changes on the CTLS. I'm pretty sure that the CTLS was also wind tunnel tested. One of the areas they worked on on the CTLS was the design of the upper cabin for airflow over the tail. The CTSW is known for stick bump in smooth air, which comes from disrupted airflow over the cabin causing laminar flow separation of the stabilator. The changes for the CTLS made the issue less pronounced.

[FlyingMonkey]

2 hours ago, Tom Baker said:

A word of caution. Everyone is telling you what works for them in their airplane. I have flown a lot of different CT's, and you can't use a cookie cutter approach. The speeds may be perfect for one airplane, and the next it will be to fast or slow. 

Agreed.  These airplanes are hand made and no two are identical.

[FlyingMonkey]

35 minutes ago, Eddie Cesnalis said:

I tend to find 62knots abeam the numbers and get my landing flaps there.  Once I have them (30 or 40) I will fly often fly well into the white arc until I'm pitching for touchdown and then I want the full flare so my balance on my mains is good and I dont' tip onto my nosewheel right away.

Speed decays quite quickly at 30 or 40 so using the entire white arc gives me the more stable feel when I want it and the slow/short rollout.  In my head I feel like I'm keeping my nose low enough to load up my flaps.

That's a good point.  I find myself flying most of my approach pretty fast in windy conditions, and just slowing it down on short final.

[Madhatter]

2 hours ago, Tom Baker said:

The CTSW was wind tunnel tested after the fact, which led to the changes on the CTLS. I'm pretty sure that the CTLS was also wind tunnel tested. One of the areas they worked on on the CTLS was the design of the upper cabin for airflow over the tail. The CTSW is known for stick bump in smooth air, which comes from disrupted airflow over the cabin causing laminar flow separation of the stabilator. The changes for the CTLS made the issue less pronounced.

I did the analysis for stick bump at the request of Tom Peghiny and did not find any boundry layer separation or disturbance in cruise. However this led me to find the upper cabin separation issue in the flare, it was a dramatic change. I have done months of vg analysis on wings and tail, but it came down to vg's behind the windshield and on the stabilator to solve the issue. The indication from Tom was that only the F2 was wind tunnel tested. Wind tunnel testing after full production would be extremely expensive to make any changes, it's best for new models.

[Tom Baker]

20 minutes ago, Madhatter said:

I did the analysis for stick bump at the request of Tom Peghiny and did not find any boundry layer separation or disturbance in cruise. However this led me to find the upper cabin separation issue in the flare, it was a dramatic change. I have done months of vg analysis on wings and tail, but it came down to vg's behind the windshield and on the stabilator to solve the issue. The indication from Tom was that only the F2 was wind tunnel tested. Wind tunnel testing after full production would be extremely expensive to make any changes, it's best for new models.

I'm just relaying what was said when the CTLS was introduced at Sebring in 2008. I don't recall whether it was one of the engineers at the show, or during dealer training. The results of that testing led to the winglets, squared off corner where the fuselage meets the wing, and the little fence at the inboard end of the flap. It also led to the reduction of maximum flap angle from 40° to 35°, and then later to 30°.