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Flaps up...when?


FlyingMonkey

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Rotation

42kt seems very slow for rotation. I have been letting the airplane fly itself off, which usually occurs about 50kt in my airplane. I will try your method and see how it goes.

I personally try to lift the nose upon full throttle to keep the nose gear wear down. Just enough to get the gear off the ground. This is pretty standard for landing strip operations too.

 

Consider the reasoning behind different styles, adapt them to your flight style, and do whatever makes you comfortable. There's a thousand different ways to fly safely, why only use one style?

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On Wednesday I tried lifting off sooner and climbing slower, per the suggestions here.  I got the nosewheel up off the ground and let the airplane come up when ready, I think it lifted off at about 44 knots.  I tried to keep the climb at 60 knots, and that definitely gave me better climb that the 67-72 knots I was using previously with 15° flaps.  It looked like right at 1000fpm with one person in the airplane and 88°F OAT on the ground.  The sink on raising flaps was more pronounced due to the slower speed, but not scary or anything...I just felt it more in the seat of my pants.

 

The airplane did seem to require more right rudder, I'm guessing due to the higher deck angle and and slower speed making the engine torque effect more pronounced.

 

EDIT:  I also waited until just before turning crosswind to raise the flaps (~600ft AGL).  That was fine, I didn't mind waiting since I was getting better climb at the slower 60kt speed.

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My general practice is to keep the elevator neutral until the airspeed is about to touch the white arc.

 

I then apply just enough back pressure to rotate the nose up into a climb attitude.

 

If done right, the plane will roll on just the mains for a second or two before becoming airborne.

 

My goal is to look like an airliner taking off, with a delay between rotation and liftoff.

 

Like this:

 

 

Needless to say, the POH takes precedence and gusty winds or a large crosswind or a soft field may all cause me to modify the above procedure.

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How about these changes.

 

  • don't raise the nose wheel simply add a little back pressure to make it light
  • accelerate to ~70kts before retracting the flaps

 

I was flying in formation to the 2nd Oregon fly-in and we stopped for a pee in Alturas.  Take-offs were restricted into the wind to prevent flying over the town so we took off cross wind.  The other CT went first and got his nose wheel up early and was blown sideways off the runway.  Luckily he got his mains clear of the ground as he departed the runway and no damage was done.  I followed and did a very positive rotation after I had flying speed and took off from the center-line.

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I was trying Anticept's technique.  It seemed to work okay, but could have the problems with crosswind that CT describes.  As I said, more rudder was needed, and I could see running out of directional control, especially to the right, in strong crosswinds.

 

Previously, I have been holding the stick neutral or slightly back, just enough to keep the nosewheel slightly light but still tracking on the ground.  In that position, the airplane would fly itself off when it was ready, which seemed to be about 48-50 knots.  I could modify that a little with a bit more back pressure, which would take a little more weight off the nose gear and probably lift off around 46 knots.  That will be my next test.  

 

I'm still playing around with rotation and liftoff technique, and I'll try some different combinations before settling on what works best for me.  Right now I'm thinking a combination of my faster liftoff with a pitch into a steeper 60 knot climb will work well.  Obviously that's just a "normal conditions" technique that will need to be modified for grass, short runways, etc.

 

I was waiting to ~70 knots and 300 feet for the flaps, but tried 60 knots and flaps up at 600ft after reading some others' comments.  To get to 70 knots from the steeper 60kt climb requires nosing over some to build the speed...I'm not sure if a better climb would be maintained from doing that or just pulling them up at an appropriate altitude and 60kts and dealing with a little more sink until the airplane accelerates.  Either one involves arresting the climb momentarily as the configuration changes. 

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Hey guys, you have to remember that we are talking about different airplanes here. What works perfect fro a CTLS or CTLSi may not be best for a CTSW. The CTSW with 15° flaps climbs at a different deck angle. It sort of levitates where the CTLS needs a positive climb angle.

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Hey guys, you have to remember that we are talking about different airplanes here. What works perfect fro a CTLS or CTLSi may not be best for a CTSW. The CTSW with 15° flaps climbs at a different deck angle. It sort of levitates where the CTLS needs a positive climb angle.

 

That's a really good point.  A ground observer mentioned the other day that my CTSW climbs very flat, that it looks "like it's on an elevator".  Not sure how the CTLS climbs, but my SW is just as you describe.

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Once a positive rate of climb is achieved, time to take out the flaps and climb at about 72kts to pattern altitude.

 

I cannot find any reference to this in the POH (CTSW nor CTLS), is CTLSi different?

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I try this once in a while.

 

Now that is interesting, is that from the CTLS POH?  A few things:

 

1)  They set initial climb at 55 knots, even though it is neither the 61kt Vy (where most manufacturers recommend climbing), nor is it the 51kt Vx.  This would make sense on a short field, but for a normal takeoff it seems climbing at Vy would be safer, to get altitude as quickly as possible.  Any idea for the reasoning behind this?

 

2)  Flaps up is listed in the 55kt climb at 150ft.  That seems very slow and very low to me...there might be a LOT of sink there, at a pretty low altitude.  I'd be more comfortable with at least 300ft under me, especially at that slower speed.  This is close to what 100Hamburger posted for flaps up.

 

3)   They keep flaps 0° through the base turn, and maintain 62kt until 15° base at midpoint of base or later; first mention of a slower speed is 55kt on final.  On final they list both 15° or 30°, presumably meaning either is considered "normal" based on condition and preference.  That will probably start a fight here shortly.   :)

 

4)  Oddly, nowhere is the max 35° flaps setting (it's 40° on the CTSW) mentioned...does this mean that setting is thought to be for getting in steep or short when needed, and not part of the "standard" approach?

 

 

That diagram has flaps coming in pretty late.  My technique is that abeam the numbers I pull power to idle, retrim, and add all the flaps I intend to use.  That puts me on approach speed just about the time I turn base, and I have lots of time to make a nice, stable approach without fiddling with flaps and trying to slow down.  

 

Given how short the final is in a CT, I'm skeptical of turning final at 62kt and then trying to add in more flaps, AND slow down, AND get the glide slope right to hit the numbers.  BTW, I make my approach at 55-58kt and maintain that from just before turning base to very short final.  

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