Overthinking the Pattern

[iaw4]

I am preparing for learning CTSW flying soon.  :-).  I read a good deal of posts here on the subject, but it would help me to lay out where I am still confused.  (I know that landings in the real world are like battles, where one needs to be able to alter the plan when things happen.  This is just a benchmark scenario.)

I want to work back from final in an idealized pattern.  My downwind is presumably about 1nm parallel to the runway.

The first set of advice I read is that 54 kias is a pretty good landing speed at the threshold, ideally with 15* flaps, but 30* should be ok, too.  (On touchdown, I want to hit stall and have a very modest sink rate, like 200-300fpm.)

The way I learned flying, I should be about be about 500' AGL on my turn to final.  Working backwards, at power-off glide, this should give me about 0.75nm glide distance IF I enter final with 55 kias.  Is this 0.75nm the right distance from the numbers to the turn to final, i.e., the length of my final leg?  (Would I be seeing about 650 fpm sink rate holding kias?!)

Work back, on entry to base, I should start out about 700' AGL.  Ed's earlier posts told me about 62 kias on turn to base.  But I can't work this out.  Can I cross 1nm with 200' loss of altitude and speed loss from 62kias to 55kias?  seems not enough.  (and what should be the sink rate on base?)

It also is a bit incongruous with what I need to target abeam the numbers.  If I fly 80 kias in the pattern and close my throttle (15* flaps), I shouldn't lose 300' and bleed off 18 kias within 0.75nm to get to the 62 knots that Ed suggested on my turn to base.  it would fit better together to make the turn to base at around 62 kias and 1000' altitude.  This would give me more energy to fly the base leg.  presumably, I can cross 1nm with 500' altitude loss and 62-55= 7 kias loss.

 

maybe put simpler: I understand we close the throttle at 80 kias abeam the numbers.  I have 26 kias speed loss and 1,000' altitude loss to work with.  I need to distribute this over downwind, base, and final.  how long should the final be?  (and, once I am down to about 60 kias, I presume I should be targeting a sink rate of about 650 fpm and keeping the airspeed at about 60 kias until shortly before the threshold?!)

yet another way to help me assess what I have to work with: how far will a level (no-altitude loss) 26 kias speed loss from 80 kias to 55 kias give me in terms of crossing distance?

 

 

[procharger]

Just hit numbers around 55 and you be good whatever it takes to get there.

[Ed Cesnalis]

A  CTSW can and should fly a much tighter pattern than a 172.   Start with legs that are less than 1/2 mile, if you have to slip to make  the numbers make them a little bigger.

Tighter and smaller (steeper banks too) than what seems right.

[Ed Cesnalis]

There are some that would say ideally with 30* flaps.  More 'landing skill' is required but I generally touch down at a lower / safer speed when using 30* as compared to 15* therefore it is ideal for me.

[FlyingMonkey]

16 hours ago, Ed Cesnalis said:

There are some that would say ideally with 30* flaps.  More 'landing skill' is required but I generally touch down at a lower / safer speed when using 30* as compared to 15* therefore it is ideal for me.

I agree, with the caveat that you should use flaps correct for conditions.  I have landed with 30 flaps on grass with 15kt direct gusty crosswind, and that was a real handful, and not at all the correct choice.  Sometimes a little faster is better and safer.

[Ed Cesnalis]

17 minutes ago, FlyingMonkey said:

Sometimes a little faster is better and safer.

Surprised that I'm not in total agreement?  Take your scenario above, I think its far better that you

 

17 minutes ago, FlyingMonkey said:

I have landed with 30 flaps on grass with 15kt direct gusty crosswind, and that was a real handful, and not at all the correct choice.

Here's my thinking.  15kt direct gusty crosswind is a handful because the gusts alter both your heading and your track unless you are already on the ground and  below 'flying speed'.  When you add speed because its a handful you end up on the ground but still with 'flying speed'  You have to slow through this speed at some point and if you don't use extra speed that point almost has to be while you are still in the air and able to fly away and try again.

If you do use that extra speed and that unwanted gust that will change your track, heading and or attitude now comes with 2 main wheels on the ground rolling out you have reduced options, maybe no good options at all.  Why not avoid this by landing at minimum speed?

-----------------------------------------------

Edit:  If I saw CT drivers rolling out on one wheel till they get slow I would be okay with even that but I have only seen one other CT driver in 12 years that can roll-out on a single main.  Almost all CT drivers either land on both mains or have the other main settle in a fraction of a second.

[FlyingMonkey]

I still touch down at stall speed, so I'm not still at flying speed, even though I might be a few knots faster.  

[Tom Baker]

26 minutes ago, Ed Cesnalis said:

Edit:  If I saw CT drivers rolling out on one wheel till they get slow I would be okay with even that but I have only seen one other CT driver in 12 years that can roll-out on a single main.  Almost all CT drivers either land on both mains or have the other main settle in a fraction of a second.

If I am landing in a crosswind the upwind wheel always touches down first. If I am near stall speed the other wheel will touch down soon after. I can roll one wheel on the ground the whole length of the runway if I wanted, but I would be above stall speed while still on the ground. BTW rolling one wheel is much easier with a tail dragger, but I used to do it routinely with Cessna 172's as a quick way to determine which wheel was out of balance.

[FlyingMonkey]

I still think this is a perception problem.  If I get all wheels on the ground at 40kt at 30 flaps or 43kt at 15 flaps, I'm not flying anymore in either configuration.  The extra three knots does not make the 15 flaps airplane any more susceptible to gusts or loss of control, because the stall speed is higher by the same amount.

You can make the argument that those extra three knots equate to higher impact energy if you do lose control, and that's true.  But it's also true that the better handling characteristics at 15 flaps in those conditions make loss of control less likely.  

If I have the choice of less likelihood of an incident, or slightly higher energy if one occurs, I'll take less likely every time.

Ed, by this same reasoning, why are you ever landing at 30 flaps at all, and not using 40 flaps on every landing to reduce your speed/energy even further?

[Ed Cesnalis]

4 hours ago, Tom Baker said:

If I am landing in a crosswind the upwind wheel always touches down first. If I am near stall speed the other wheel will touch down soon after. I can roll one wheel on the ground the whole length of the runway if I wanted, but I would be above stall speed while still on the ground. BTW rolling one wheel is much easier with a tail dragger, but I used to do it routinely with Cessna 172's as a quick way to determine which wheel was out of balance.

That's good stuff in a CT Tom

[Ed Cesnalis]

3 hours ago, FlyingMonkey said:

I still think this is a perception problem.  If I get all wheels on the ground at 40kt at 30 flaps or 43kt at 15 flaps, I'm not flying anymore in either configuration.  The extra three knots does not make the 15 flaps airplane any more susceptible to gusts or loss of control, because the stall speed is higher by the same amount.

You can make the argument that those extra three knots equate to higher impact energy if you do lose control, and that's true.  But it's also true that the better handling characteristics at 15 flaps in those conditions make loss of control less likely.  

If I have the choice of less likelihood of an incident, or slightly higher energy if one occurs, I'll take less likely every time.

Ed, by this same reasoning, why are you ever landing at 30 flaps at all, and not using 40 flaps on every landing to reduce your speed/energy even further?

Good comments and questions Andy,

In calm winds the real world difference in touch down speed between 30 and 15 tends to be more than 3kts.  When you add a gusty crosswind the delta increases maybe a lot.

This idea: 'Better handling characteristics in the air'  totally misses the point.  If you are keeping the handling crisp while still in the air then maybe you (not you personally) are over your head?  In the air with a CT/Rotax is fundamentally easy, just firewall the throttle and your gone.  On the ground, above stall, you might be helpless.

40* in my CT results in sink that I cannot reliably arrest with stick alone.  My worst case landings require closing the throttle to get the plane and runway to meet and if there isn't enough stick to soften the contact I could break my gear.

[Roger Lee]

What was wrong with the roads? Why a rough field?

[WmInce]

On 11/17/2018 at 9:58 AM, Tom Baker said:

I can roll one wheel on the ground the whole length of the runway if I wanted, but I would be above stall speed while still on the ground.

Next time there is a gusty crosswind . . . send us a video of that. I’d like to see it.

[Ed Cesnalis]

23 minutes ago, WmInce said:

Next time there is a gusty crosswind . . . send us a video of that. I’d like to see it.

You can make a nice video in a calm wind. 1/2 the distance on the left then transition to the right for the last 1/2 of the distance.

[207WF]

Nothing sets this group off like a question on landings!   WF

[FlyingMonkey]

1 hour ago, 207WF said:

Nothing sets this group off like a question on landings!   WF

If the CT came without flaps this forum would have like ten posts.  

[Tom Baker]

34 minutes ago, FlyingMonkey said:

If the CT came without flaps this forum would have like ten posts.  

One of the airplanes I fly regularly doesn't have flaps, and it has its fair share of landing discussions.

[FlyingMonkey]

10 minutes ago, Tom Baker said:

One of the airplanes I fly regularly doesn't have flaps, and it has its fair share of landing discussions.

IS THERE NO ESCAPE?!?

[WmInce]

53 minutes ago, FlyingMonkey said:

IS THERE NO ESCAPE?!?

Yes.

Helicopters!

[Anticept]

NOTAR or not?

Piston or turbine driven?

How many rotor blades?

There's always an argument to be had

[sandpiper]

On 11/20/2018 at 3:27 PM, Anticept said:

NOTAR or not?  Not

Piston or turbine driven?  turbine

How many rotor blades? 2

There's always an argument to be had

Answers in red. I might be prejudice.

[Anticept]

R-22 or R-44?

[WmInce]

11 hours ago, Anticept said:

R-22 or R-44?

More along the lines of S-76.