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-   The Pacific: General Aviation & Questions (https://www.pprune.org/pacific-general-aviation-questions-91/)
-   -   Take-off technique in light singles and twins (https://www.pprune.org/pacific-general-aviation-questions/631980-take-off-technique-light-singles-twins.html)

aroa 30th Apr 2020 07:39

A Jabiru pilot I once knew had a fetish for 3 point landings ...with the nose wheel impact first.!
His life was a series of burst tyres, dinged props;; busted nose legs and matchwood props.
One thing he never did, or a least I never saw him do, wheelbarrow off the strip into the fence, as did someone with a Cherokee 140.

mullokintyre 30th Apr 2020 11:18

The single Comanche was equally guilty of wheelbarrowing very quickly if you tried to hold it down.
I was co pilot in a Commanche 180 taking off from a very wet and gusty Narromine many years ago.
The pilot said he would hold it down a little longer than normal to try to counteract the gusty cross winds.
Before we knew what had happened the aircraft speared off the runway into the grass.
Fortunately, we didn't do much damage, but it was virtually the end of that pilots flying career.
he never really recovered from the experience. Lucky of me, I did.
I was very careful with the Commanche to let it fly off when it was ready after that.
Mick

machtuk 30th Apr 2020 11:49

The smaller nose wheel some Comm drivers had makes a difference, I used to also rarely land with full flaps in the Comms, much better handling machine-)

cattletruck 30th Apr 2020 13:22

No one has mentioned setting the trimwheel yet, it's in the POH and also part of of the T/O checks. Set it right and you can almost close your eyes... almost.
I only close them just before touchdown - works every time.

Capt Fathom 30th Apr 2020 22:19

Who would have thought takeoffs were so complicated? :}


Squawk7700 3rd May 2020 07:50

On the topic of nose-draggers... I had never realised how small they are on these until I stumbled across this in my videos.


https://cimg6.ibsrv.net/gimg/pprune....efa589aec0.jpg

mustafagander 3rd May 2020 10:51

The AFM is generally a good guide.

Beware instructors' good ideas.

Runaway Gun 3rd May 2020 23:24

I've witnessed a few students raise the nose very high, very early on in the takeoff run. Why? "To get the weight off the weak nosewheel."
But with consequently high drag, degraded forward visibility, lengthened takeoff run, and it being very lose to the stall on liftoff.

Yet the same pilots will happily smash that nose wheel down upon landing...

Ex FSO GRIFFO 4th May 2020 01:53

Does 'Ronny' land those things on sealed rwys only, or do they occasionally put them onto gravel / sand?

Just curious is all.....

Cheers

421dog 4th May 2020 02:17

I fly primarily heavy piston and light turbine twins. Given sufficient runway, i always opt for blueline prior to a posiive rotation. In piston planes such as 400 series Cessnas that will accommodate strut variances to allow for a nose down runway attitude requiring a positive rotation, I’ll do that, stick to a Blueline rotation and, if I’m after balanced field length, know that I can make it off even without a published V2.

sheppey 4th May 2020 04:49


I always opt for blue line prior to a positive rotation.
Let me play the Devil's Advocate here. What is the difference between normal rotation and "positive" rotation?" Forcing the aircraft to stay on the runway until 20 knots or more between manufacturers recommended rotation speed and Blue Line speed is getting into test pilots territory.

Be careful if using your own personal technique particularly if something should go wrong. Any Regulatory investigation would have you by the balls if it was determined you disregarded the manufacturers POH operational advice. The legal eagles would also take you to the cleaners.
You don't hear of airline pilots flying their 777's or A330's throwing away the book and using their own speeds. With all due respect you would be wiser to stick with the POH figures. Chances are you could increase the chances of blowing a tyre due using excessive speed on the runway. Trust the flight manual numbers. The investigators will.

machtuk 4th May 2020 06:12


Originally Posted by sheppey (Post 10771824)
Let me play the Devil's Advocate here. What is the difference between normal rotation and "positive" rotation?" Forcing the aircraft to stay on the runway until 20 knots or more between manufacturers recommended rotation speed and Blue Line speed is getting into test pilots territory.

Be careful if using your own personal technique particularly if something should go wrong. Any Regulatory investigation would have you by the balls if it was determined you disregarded the manufacturers POH operational advice. The legal eagles would also take you to the cleaners.
You don't hear of airline pilots flying their 777's or A330's throwing away the book and using their own speeds. With all due respect you would be wiser to stick with the POH figures. Chances are you could increase the chances of blowing a tyre due using excessive speed on the runway. Trust the flight manual numbers. The investigators will.

I have to agree here, the AFM isn't a book full of 'suggestions'! I've got 1000's of hrs on B200's for Eg I would rotate at the proper speed 95 kts NOT 120 or so that's just asking for trouble!

421dog 4th May 2020 10:37

Let me play advocate as well: One I fly is a c-421 with a Robertson STOL kit installed. Per the (updated) manual, I should be dragging it up at 74 Kts, after 800 and change feet of ground run with 15 degrees of Fowler’s out.
If something were to happen prior to blueline. I suspect it wouldn’t be pretty.
Conversely, at Blueline, it’s about as exciting as afternoon tea to either shut it down or continue the takeoff depending on remaining runway length. (Multiple simulator goes at my annual recurrent training in a level 4 with the perfomance numbers plugged in, and at least one actual where particulate contamination caused an engine failure at 20 ft or so)

I’ve shut down a couple times at sub-blueline speeds when somebody coked up a turbocharger and I ended up with asymmetric thrust, (interestingly, it was well below Blueline, but likely around where I’d have been off the ground in a max performance takeoff when it became apparent. Those GTSIO 520s have a lot of stones)


i need to acknowledge that I have zero issue with the numbers in the several King Airs, MU-2s 425’s or PA-42s that I fly. On these, I’m by the book.

CAVOK92 5th May 2020 06:22

Out of interest what is Vyse in a modified c421? Having only flown 404/2’s With Blue line around 107kias. Staying on the ground until then sounds a bit exciting.

Big Pistons Forever 5th May 2020 18:52

Most of my hours on Piston Twins (around 2000 hrs) is on the Navajo series, Cessna 340 and Piper Aerostars. All sit pretty level so you can roll to relatively high speeds without the aircraft getting light on its wheels. Personally I lift off at 5 to 7 knots below blueline which is around 100 kts for the types listed. I start a gentle pitch up at 95 and the aircraft comes off the ground smoothly and cleanly at around the 100 kt mark. Positive rate, blue line and gear up comes in a few seconds later and now I have some options. Climb out is blue line +5kts to 500 AGL and then a smooth transition to 120- 125 kts at which time I go to climb power

One thing that is critical to understand is if you are anywhere near to the ground and not at blue line speed with the gear up your only option is to close throttle and glide to a forced landing straight ahead.

Turbine aircraft are a different story. With auto-feather and real performance you are in another world and those I fly in accordance with the AFM procedures.

Mach E Avelli 6th May 2020 01:22


Originally Posted by Big Pistons Forever (Post 10773562)
Turbine aircraft are a different story. With auto-feather and real performance you are in another world and those I fly in accordance with the AFM procedures.


However all is not as it seems with some turbine AFMs. Beech claim a V1/Vr of 95 knots for a zero flap take-off. This is NOT a 'true' V1/Vr in that the power-off stall speed at gross weight flap zero is more like 100 knots, i.e. VSi is above the 'V1/Vr' they quote. While the wing is being 'blown' by two good engines no harm will result from a smooth rotation at 95 knots and about 5-10 seconds later blue line will have been achieved (if the pitch attitude is not above about 7- 8 degrees nose up - all engines operating). To achieve advertised take-off run performance the correct rotate speed of 95 knots is required.
But throw in a total loss of power on one side as you rotate - even with the autofeather doing its thing - and you would be well advised to put it back on the ground just like you would in your light piston twin. Better to take out the farmer's fence than to dig him a new well.
To those who say that they can handle a failure at 95 knots in a B200 at gross weight flap zero and fly it away safely I would recommend some simulator at high weights, rather than what you may have experienced during benign base training at light weights.
Another aircraft that can get quite exciting if the failure occurs at Vr is the MU2. No way can you safely fly that thing away from just off the ground with an engine failure. Yet to my mind - treated with due respect - the MU2 is the best light turboprop ever built.

421dog 6th May 2020 02:16

+1 on the MU-2
spoilers are a little confusing to the unitiated, (and did in the guy that got me my first gig in one on a windy night takeoff with a ton or so of newspapers and cancelled checks at MDW many years ago).

Functionally overpowered with high enough wing loading that it doesn’t bounce around. I loved every one I flew and woud love to fly one again.

421dog 6th May 2020 02:32


Originally Posted by CAVOK92 (Post 10772898)
Out of interest what is Vyse in a modified c421? Having only flown 404/2’s With Blue line around 107kias. Staying on the ground until then sounds a bit exciting.

VYse with the STOL is listed as 95 KIAS vs 125 KIAS unmodified.

deja vu 6th May 2020 08:41

Talking about lifting the nose wheel off early, who could ever forget the footage of Doolittle's B25 Mitchells launching off a carrier bound for Tokyo. Google it. Considering the limited deck space I'm not sure if it was the best technique!!

machtuk 6th May 2020 09:30


Originally Posted by Mach E Avelli (Post 10773826)
However all is not as it seems with some turbine AFMs. Beech claim a V1/Vr of 95 knots for a zero flap take-off. This is NOT a 'true' V1/Vr in that the power-off stall speed at gross weight flap zero is more like 100 knots, i.e. VSi is above the 'V1/Vr' they quote. While the wing is being 'blown' by two good engines no harm will result from a smooth rotation at 95 knots and about 5-10 seconds later blue line will have been achieved (if the pitch attitude is not above about 7- 8 degrees nose up - all engines operating). To achieve advertised take-off run performance the correct rotate speed of 95 knots is required.
But throw in a total loss of power on one side as you rotate - even with the autofeather doing its thing - and you would be well advised to put it back on the ground just like you would in your light piston twin. Better to take out the farmer's fence than to dig him a new well.
To those who say that they can handle a failure at 95 knots in a B200 at gross weight flap zero and fly it away safely I would recommend some simulator at high weights, rather than what you may have experienced during benign base training at light weights.
Another aircraft that can get quite exciting if the failure occurs at Vr is the MU2. No way can you safely fly that thing away from just off the ground with an engine failure. Yet to my mind - treated with due respect - the MU2 is the best light turboprop ever built.

i look at the speed diff on the speedo of say 95 -121 as a 'no-mans-land' (kinda like Heli Ops on T/O) if you can't accelerate to 120 or so knots by whatever means then it's game over!
Vr is the speed at which the invitation of rotating begins, I was never in a hurry so going thru 35' I was well on my way to the speedo saying 120 kts or so.


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