Flaps up...when?

[FlyingMonkey]

My CT seems to climb and accelerate much better at 0° or -6° flaps than at higher settings.  I have been playing around with the best time to raise the flaps on takeoff (I usually take off at 15° flaps).  When going from 15° to 0° there is a pronounced "settling" that feels like you are sinking for a second or two, though I'm sure it's actually just a decrease in rate of climb, until the airplane accelerates a bit. 

 

My instructor's CTSW used to get hot very quickly in climb, so he would put the flaps up to -6° almost as soon as he had a good climb going.  I'm more conservative, and want to make sure I'm not going to settle dangerously on takeoff.  I tried using 70kts speed as my criteria to go to 0°, but sometimes I'm still a bit low at that speed.  So I switched to 300' AGL AND minimum 70kts speed.  That works out, but I wonder if I'm leaving a little performance on the table.

 

BTW, I usually stay at 0° when remaining in the pattern, otherwise the CT wants to go too fast on downwind.  Even at 0° I'll go to fast if above 4000rpm on the downwind leg.  When I'm leaving the pattern I usually go to -6° almost immediately after going to 0° since the settling affect in that change is almost imperceptible and by then I have plenty of altitude.  

 

How do ya'll do it?

 

 

[Ed Cesnalis]

I stay at 15 until I'm 600' AGL.  At that altitude I'm willing to do the impossible turn so it seems a good time to change configuration.

 

When I go to zero back pressure and nose up trimming are automatically needed.  I think there is some settling if you let it.

 

I too fly the pattern at zero, reflex flaps is too fast.

[Roger Lee]

I'm with ED. 15 flaps until I reach a 180 capable turn, which is around 400-600 ft. Then I make throttle and flap adjustments. I was always taught leave things alone while climbing well because if something ugly happens it could be when changing flaps or throttle. At 400-600 ft. You can go straight, turn 180 or safely pull the cute.

[FlyingMonkey]

But it takes longer to get there...On a very hot day I climb about 750fpm at 15°, when I go to 0° the climb shoots up to ~1200fpm solo.

[ralarcon]

I stay at 15 until I'm 600' AGL.  At that altitude I'm willing to do the impossible turn so it seems a good time to change configuration.

 

When I go to zero back pressure and nose up trimming are automatically needed.  I think there is some settling if you let it.

 

I too fly the pattern at zero, reflex flaps is too fast.

 

Ditto, Cheers

[Roger Lee]

15 flaps will get you higher in a shorter distance. You're off the ground quicker and climb faster. If you are having high oil temps then try my fix on the video.

 

You know which one.

[FlyingMonkey]

So you don't raise flaps until you are ready to turn crosswind...that seems a long time. 

 

I'll give it a try and see how it goes.  I got the 300' number from when I trained in a Tecnam at Lockwood.  That was the number they used.

[FlyingMonkey]

What airspeed to you aim for in these 15° flap climbs?

[Ed Cesnalis]

What airspeed to you aim for in these 15° flap climbs?

 

 

If you ever get to operate at a high elevation field the take off and initial climbs are quite different.  If I take off from sea level my pitch attitude is quite high like I see on other CT's videos.

 

When I take off from Mammoth I begin with back pressure and as my mains come up I lower my nose while still in ground effect.  I keep lowering the nose unitll I have 58kts.  After that I keep the nose low until 68kts and then climb at that speed.  My CT would be happy to climb away at 45kts IAS but that's not enough margin in our local wind shear washing machine.

 

My thinking is to get good margin over stall and an attitude that won't be too exciting if the motor quits.  Solo I will get ~1000fpm at some point, usually when I encounter the first blast of wind shear.

[sandpiper]

I stay at 15 until I'm 600' AGL.  At that altitude I'm willing to do the impossible turn so it seems a good time to change configuration.

 

When I go to zero back pressure and nose up trimming are automatically needed.  I think there is some settling if you let it.

 

I too fly the pattern at zero, reflex flaps is too fast.

Ditto. If I am 400 ft AGL I want to be set to do the 180. For me that means flaps 15.

[Ed Cesnalis]

Ditto. If I am 400 ft AGL I want to be set to do the 180. For me that means flaps 15.

 

At 400 it will be a downwind landing, above 600 I sometimes think I could fly a pattern and land upwind.  In Mammoth it would be a wrong sided pattern because on the normal downwind side there is terrain 700' ARL  (above runway level)

 

To the right the terrain is 1,100 ARL but that moraine is a little farther away.  Depending on when she quit and my altitude I would likely do a figure 8, first towards the high terrain to the right and then a big left back to the runway and then If I'm high a left turn to a right downwind and a right turn to final. 

[sandpiper]

So you don't raise flaps until you are ready to turn crosswind...that seems a long .

At my field elevation, 175 ft, I am at 400 ft AGL well before crosswind. In fact, conditions right, I am at 400 AGL by the end of our 3000 ft runway. My initial climb is done at 60K. Then flaps to zero, then flaps -6 and accelerate to 86K (best rate of climb) if leaving the pattern.

 

If staying in the pattern flaps only go to zero and I shoot for max 80K because I want to be ready to go flaps 15 at some point then flaps 30 abeam the numbers .

[sandpiper]

At 400 it will be a downwind landing, above 600 I sometimes think I could fly a pattern and land upwind.  In Mammoth it would be a wrong sided pattern because on the normal downwind side there is terrain 700' ARL  (above runway level)

The downwind landing can be a problem at my 3000 ft runway. Doable with flaps 40 and aggressive slip. Sometimes I wonder if it would be better to turn left 90 degrees, like a crosswind, then a right 270 to a downwind final.

 

Every situation is different and requires practice. Which I haven't done enough of lately..

[Anticept]

Hi all!

 

You will climb faster with 0 and -6 flaps than you will with 15 flaps. 15 flaps will get you higher in a shorter distance, but it will take more time because a lot of aerodynamic efficiency is wasted.

 

I personally raise flaps once I am reasonably above flaps retracted stall speed plus any gust margin. I also try to get that Vy as quickly as reasonably possible. In my Mooney, right after leaving the ground, I will level out some to retract gear and flaps, wait for Vx speed, then pull up into the climb while continuing to gain speed for Vy. Granted in shorter airfields this isn't a good idea, but I have lots of runway space to play with, so I prefer to stay close to the ground for a quick abort.

 

As for my CT, I do whatever feels interesting at the moment.  Sometimes I'll burn up every inch of runway with flaps raised, get to 100+ knots, then climb hard .

[Ed Cesnalis]

The downwind landing can be a problem at my 3000 ft runway. Doable with flaps 40 and aggressive slip. Sometimes I wonder if it would be better to turn left 90 degrees, like a crosswind, then a right 270 to a downwind final.

 

Every situation is different and requires practice. Which I haven't done enough of lately..

 

 

I see the irony in killing yourself running off the end of the runway doing the impossible turn.

 

It is not only possible but you may very likely need additional maneuvering to hit the numbers and not overshoot.  Personally I don't sweat it with a 7,000' runway plus a 2,000' overrun created by the remnants of the old runway.

[sandpiper]

Hi all!

 

You will climb faster with 0 and -6 flaps than you will with 15 flaps. 15 flaps will get you higher in a shorter distance, but it will take more time.

 

 

As for my CT, I do whatever feels interesting at the moment.  Sometimes I'll burn up every inch of runway with flaps raised, get to 100+ knots, then climb hard .

Gotta have some fun once in a while. At our 3000 ft runway I can hit 100K by the departure end.

[FlyingMonkey]

Maybe my dissatisfaction with the 15° flap climb is that I'm "doing it wrong".  I usually seem to be at 65-68kt climbing in that config...maybe I need to try it at 60kt and see if that helps.

[coppercity]

We generally teach 15 flap takeoffs as rotate around 42kias, initial climb at 55 kias to 50 ft or clear obstacle. Then transition to 60 kias to a safe altitude of around 250ft prior to transition to 0 flaps then climb at 73kias. 0 flaps if staying in the pattern, -6 on pattern departure climbing at 78kias or 90 kias for a cruise climb.

[Roger Lee]

I get my biggest altitude gain at 15 flaps at 60 knts. Yes you could go back as far as 50-55, but 60 puts you already in a glide setup and doesn't overload the engine on temps. I have tried  zero flaps for altitude gain, but 15 is the winner. Some of this will also depend on aircraft gross weight at take off. At 15 flaps and 60 knts and taking off at a 2400' elevation I can easily see a 500-600 ft gain before crosswind.

 

Light butts climb faster and heavy butts climb slower. You'll have to figure which one you are and are you comparing climb rates with 2 people or one.

[FlyingMonkey]

We generally teach 15 flap takeoffs as rotate around 42kias, initial climb at 55 kias to 50 ft or clear obstacle. Then transition to 60 kias to a safe altitude of around 250ft prior to transition to 0 flaps then climb at 73kias. 0 flaps if staying in the pattern, -6 on pattern departure climbing at 78kias or 90 kias for a cruise climb.

 

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.

[Andy]

I also use 42 kts as a rotation speed with 15 flaps and a 60 kt climbout.  At 300 ft AGL, I lower the nose to get no flaps Vx and raise flaps to zero, continue at Vx if necessary or lower the nose to get to Vy if not.  I leave the flaps at 0 if staying in the pattern and only transition to minus 6 once I level off for cruise.

[Ed Cesnalis]

I use back pressure from the beginning of my take off roll and let it fly off when its ready.  The exception is for big crosswinds where I sometimes need a positive rotation to avoid being blown sideways while my mains are still in contact. 

 

The backpressure seems kinder to my nose gear.

[Runtoeat]

Ditto with Ed.  Back pressure at the start of the roll, let plane lift off. 15 flaps and keep nose down until 60kt climb on short or grass fields and 0 flaps and 65kt climb on long runways.  If takeoff was 15 flaps raise to 0 flaps after 700' AGL and raise again to -6 after achieving pattern altitude.  Note my airport elevations are typically 600' to 1500' MSL or less.

[FlyingMonkey]

I'm in the same situation, Dick.  My home airport is 940ft MSL and most of the surrounding airports are 600-1100ft MSL.

[GravityKnight]

Depends on weight and conditions for me. If I'm heavy and it's hot out, I wait much longer to go back to 0. When we left Page on the trip back from Las Vegas with a heavy plane, I waited quite a while before I raised them. The plane sank a lot, and it took a long time to start climbing again. I could have waited longer honestly, it sank a lot more than I expected!

 

On a cool day by myself, the drop is very minimal if I get the plane to 65+ knots at -15 and then raise them. I would imagine at sea level in a light plane on a cool day the sink would be no big deal....