Take-off technique in light singles and twins

[Centaurus]

Australian Flying magazine May-June 2020 published an article by Steve Hitchen on his test flight of the Tecnam P Twenty-Ten at South Port, Q'ld.
Certainly seems a flash looking four seater with upgraded electronics and prestige interior.

The demonstration instructor's takeoff technique was similar to that commonly taught at flying schools on Cessna and other light singles in that the weight is taken off the nosewheel during the takeoff roll by early back pressure on the control wheel.

Steve writes that his instructor advised him to:
"Smoothly and quickly go to full throttle and as soon as you have elevator authority lift the nose so that it's about two inches off the ground and hold it straight with rudder. Around 55 knots the aircraft will start getting light on the undercarriage and will lift off around 60 knots"

For ab initio and even experienced pilots, it would be difficult to judge two inches for the nosewheel to be raised above the runway - particularly at night where nose attitude is difficult to judge. The potential for inadvertently using too much back pressure to raise the nose wheel off the ground early in the takeoff run is that it may cause the aircraft to become prematurely airborne in ground effect before it reaches the recommended takeoff speed. That has its own hazards

With any aircraft it would be better airmanship to stay with the manufacturer's recommended take off technique, rather than the instructors personal technique - in this case playing with lifting the nosewheel two inches clear of the runway during the takeoff run? Unless the takeoff surface is soft or rough why lift the nose-wheel early in the takeoff run when there is no operational need to do so?

The Comet jet airliner was involved in 26 hull-loss accidents (https://en.wikipedia.org/wiki/Hull_loss), including 13 fatal crashes which resulted in 426 fatalities. Pilot error was blamed for the type's first fatal accident, which occurred during takeoff at Karachi, Pakistan (https://en.wikipedia.org/wiki/Jinnah_International_Airport), on 3 March 1953 and involved a Canadian Pacific Airlines (https://en.wikipedia.org/wiki/Canadian_Pacific_Airlines) Comet 1A.

In those days, De Havilland, the manufacturer of the Comet, recommended that during the take off roll the nose be raised at 80 knots and the aircraft allowed to fly off the ground when it was ready - in other words not at a specific rotation speed. The short nose of the Comet made it difficult for the pilot to visually judge nose attitude when lifting the nose at 80 knots - especially at night. It was all too easy to over-rotate. In addition limitation of artificial horizon design often caused the instrument to be unreliable during aircraft acceleration.

. A similar take off technique was used by the RAF on the De Havilland Vampire and English Electric Canberra bomber. The RAF Pilot's Notes for the Vampire F1 stated: "As soon as the aircraft reaches a speed of 60-70 knots IAS, lift the nose wheel just clear of the ground, then at 82-87 knots ease the aircraft off the ground. The date of the Pilots Notes was January 1947. The first flight of the Comet was also in 1947. There was speculation that nose wheel early lift off may have been to cover the case of nose wheel drag build up caused by the nosewheel impacting on slush during the takeoff roll.

Both early accidents were originally attributed to pilot error, as over-rotation had led to a loss of lift from the leading edge of the aircraft's wings. It was later determined that the Comet's wing profile experienced a loss of lift at a high angle of attack, and its engine inlets also suffered a lack of pressure recovery in the same conditions. As a result, de Havilland re-profiled the wings' leading edge with a pronounced "droop", and wing fences were added to control spanwise flow. The Comet takeoff technique was changed following the results of the investigation

It should be remembered that handling techniques are recommended by the manufacturer's properly qualified company test pilots. That includes takeoff and landing. These will normally be incorporated in the aircraft flight manual or AFM. Instructor personal techniques for takeoff and landing that do not accord with the manufacturer's POH could attract the risk of litigation should an accident occur.
If there is no valid operational reason for changing a flight manual recommendation, then be careful what you teach. It could come back to bite you.

[spektrum]

Are we seriously going to have the debate that easing weight off the nose-wheel in VERY light aircraft is likely to cause DEATH? I'd say it's good airman-ship especially on an unsealed surface.

[Sunfish]

Centaurus already made that observation regarding unsealed or soft surfaces, it’s in the C172 POH from memory. I am also advised, but have no experience, that the C210 will not accelerate if you lift the nose below some rotation speed, and you will just travel the length of the runway in a nose high attitude. I don’t know if others are as tender.

It all depends on weight, CG position and elevator authority. A rear CG at MTOW, a hot day and a big elevator could give you grief no matter what you might think. Then there is the little matter of directional stability.

[machtuk]

I don't know know how the many thousands of T/Off's I've done where I didn't raise the nose wheel off the ground early that I come to get away with it!:O

[Squawk7700]

Many types of light aircraft such as the Tecnam in the article, achieve improved directional stability when weight is lifted off the nose wheel. The issue mainly comes from the shape of the tire where it is too “square” across the bottom and too much weight on the nose results in the feeling of riding on the backbone of a poddy-calf, for those farmers amongst us.

The other issue with these small tires is that they are near on impossible to balance in some cases and the whole front end of the aircraft will shake until it slows down after a high speed takeoff. The bigger and heavier Cessna style wheels appear to not suffer as badly from this issue, if at all.

[MagnumPI]

I always appreciate your posts and anecdotes Centaurus. As a low-time pilot they give me offer some great perspective.

I also read the article and was wondering why the instructor gave that procedure. Having never flown a P2010, I found a flight manual online to check on this. As far as I can see the manufacturer's recommended normal procedure is to rotate at 60KIAS.

At the flying school I learnt at we were told to keep controls about neutral during the takeoff run (whilst allowing for cross-wind correction of course) until rotation speed. Soft-field ops are naturally different.

I flew recently interstate at an aero club flying school which seemed to have a sound reputation. The instructor was great to fly with, but I had to question some of the odd (at least to me) items on their school checklist...like checking that the engine was 'ON' after you'd started it! They also insisted on radio calls for every leg of the circuit. When I queried this I was told it was because it is a busy aerodrome, and no further explanation was given.

I suspect that students who learn in that environment are likely to carry those habits elsewhere. Unnecessary radio congestion would surely be detrimental to see and avoid at most places.

In fact, the more I fly at local airports around the country, the more I am grateful for the 'old school' training that I've had which focussed more on airmanship, common sense, and simple checklists that could easily be committed to memory and would apply across most light single engined aircraft.

[TCAS v2]

From memory the Cessna 182 POH says that for a normal take-off, leave the nose on the ground and lift it at 50-60 kt.

That seems pretty sensible.

[Old Akro]

What is a nosewheel??

[Sunfish]

Game, set and match to Akro!

[Greeb]

What is a nosewheel??
It's when they put the tailwheel on the wrong end. :E

[mullokintyre]

Most training wheel Vans RV pilots (excluding 10 and perhaps 14) will be advised to get the nosewheel off as soon as practical.
This is mainly due to the propensity of the shoddy RV nosewheel design that can fail because of the fore and aft oscillation of the long stiff gear leg that has a tendency to dig into the runway and act as spring to flip the aircraft over.
Has happened numerous times, and vans have finally acknowledged its shortcomings by putting out a new design front gear leg for RV's.
Big and expensive job though to replace on an existing aircraft.
Mike Seager who does the transitional training for all RV aircraft, teaches that it is important to get the nosewheel of as soon as possible, and to keep the nosewheel off the ground for as long as possible on rollout fter landing.
Mick

[machtuk]

Careful guys the nose dragger trainer fraternity will be up in arms especially the Vans 'A' fansboyz! :O

[harrryw]

Careful guys the nose dragger trainer fraternity will be up in arms especially the Vans 'A' fansboyz! :O
What is a wheel?
https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Orville_Wright%26flyer1909.jpg/1280px-Orville_Wright%26flyer1909.jpg

And nosewheels are what you put on the ground first to stop too much weight being put on the big wheels at once.

.

[mullokintyre]

I have a foot in both camps. I built an RV9a, but wished I had built a taildragger.
Mick

[Seabreeze]

What is a wheel?
https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Orville_Wright%26flyer1909.jpg/1280px-Orville_Wright%26flyer1909.jpg

And nosewheels are what you put on the ground first to stop too much weight being put on the big wheels at once.

.
Put the nosewheel on the ground first? WTF?
Only if you want to hop down the runway like a kangaroo.!
SB

[Ixixly]

Put the nosewheel on the ground first? WTF?
Only if you want to hop down the runway like a kangaroo.!
SB

I think he was employing a narrative device known as "Sarcasm" :P

But from it seems here this technique is to cover a deficiency in design where they'd rather add in a couple of extra lines to a POH than go back to the drawing board and fix it up properly? At first look without any real reference the first things that come to mind is that the wheel does look awful tiny and would suffer from a lot of shimmy but I can't quite put my finger on why exactly.

[sheppey]

the wheel does look awful tiny and would suffer from a lot of shimmy but I can't quite put my finger on why exactly.

Talking about nose wheel shimmy. Prior to all the new construction that led to Essendon Fields was a one man flying school run by an eccentric whose name escapes me. He owned a clapped Piper Apache that he hired out cheaply (bring your own elastic band to hold the door handle in place).

Some teenage kid managed to get into and start one engine and tried to taxy and hit the cyclone fence at the back of the Apache. The owner went ape and kicked the kid in the guts after the gendarmes caught the kid and held him until the owner arrived. The owner then kicked the female cop who tried to tell him to back off.

We cross-hired the owner's Cessna 150 and the instructor designated to fly it saw the nose-wheel tyre was deflated. The instructor pumped it up to the correct pressure and departed. On landing back at Essendon the aircraft experienced nose-wheel shimmy so serious that the instructor thought there may be unseen airframe damage the shimmy was that bad. He wrote it up in the maintenance release.

The owner who had a short fuse, went mad at him for not only sullying the maintenance release with a defect entry but also for pumping up the nose-wheel tyre to the correct pressure. That was because the owner had deliberately dropped the nose wheel tyre pressure 50% to minimise the nose-wheel shimmy which had been a feature of that Cessna 150 for months. Slight thread drift maybe but over the years there has been some interesting characters who ran flying schools at EN

[oggers]

With any aircraft it would be better airmanship to stay with the manufacturer's recommended take off technique, rather than the instructors personal technique - in this case playing with lifting the nosewheel two inches clear of the runway during the takeoff run? Unless the takeoff surface is soft or rough why lift the nose-wheel early in the takeoff run when there is no operational need to do so?

I agree. That technique is most likely to be counter-productive except in the soft field case. Rolling resistance on a firm surface is small compared with aerodynamic drag at TO speed. Only when the ground is soft enough to push the rolling resistance up to some figure (ie about that of soft turf) does the extra aero drag penalty of significant back pressure become a worthwhile trade-off - purely from a performance perspective and notwithstanding other considerations such as eliminating shimmy or dealing with potholes of course. Stick with the manufacturers recommended technique.

[Big Pistons Forever]

Light singles: I teach the student to establish the takeoff attitude when the elevator becomes effective and let the aircraft lift off when it is ready

Light twins: I teach that the aircraft maintains a level attitude with the nose wheel on the runway until rotate speed. This is so that in the event of an engine failure on the takeoff roll the pilot will have the benefit of nosewheel steering to help maintain directional control. The only exception is the Twin Comanche. Because of its very nose high attitude on the ground care must be taken not to hold it on the ground therefore I let it lift off from the ground attitude when it is ready, so no real rotation, and then briefly hold it level in ground effect to let the speed build to a safer value and then climb away

[International Trader]

I agree with Centaurus and I always enjoy his articles , not to mention his genuine wish to pass on information that may well be lost if nothing is said here.
I also agree with Swark7700 and his take on the subject.
Light aircraft instructing was something that I did many decades ago and I remember that many aircraft ( especially the very light ones) would rattle down the runway if the pressure was kept on the nose wheel to the terror of the students. Taking the pressure off did ease the situation sometimes and I always put it down to sh-tty design , the maintenance that plagued the industry in those days or the result of students landing on the nose wheel and possibly bending the structure.
Civil instructors are always customer focused , for the obvious reason and, you try to achieve the goal by using lateral thinking while still trying to be safe.
Some one I once new said: 'Unlike in the military, a punter only gets washed out when he runs out of money, enthusiasm or scares himself enough to give up.'
Some times an instructor will dumb down a technique a bit much and you end up with something like lifting the nose wheel off the ground instead of taking the pressure off the wheel. Of course, sometimes with particularly bad maintenance, the vibration was worse with the nose wheel just spinning on worn out bearings than with some pressure on it!

I also demonstrated aircraft for sale to many greedy investors with more finance than ability and was ( at times ) told to 'make sure you show them that he aircraft performs perfectly'.
One time I had to demonstrate that a Partenavia could maintain altitude on one engine with a full pax complement ( or almost full as I recall all the group potential purchasers were on board).
From memory, the certification requirement was a 1% climb rate at 5000', on one engine ( for a new aircraft).
Well, we weren't at 5000', one engine was at 'zero thrust' setting ( or maybe a little more) and we just managed to get a little climb out of it.
I for one was surprised , the purchasers didn't notice and were impressed enough to lay their money down..

A demo pilot is charged with making sure the aircraft performs and in this case , maybe this is the dumbed down technique that he preached to journalists of unknown ability
to achieve his goal.

Keep the stories coming, Centaurus!

[aroa]

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]

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]

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]

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]

Who would have thought takeoffs were so complicated? :}

[Squawk7700]

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.org-vbulletin/1201x532/pc21_242f3f95c90e319d11d37c37b0c388efa589aec0.jpg

[mustafagander]

The AFM is generally a good guide.

Beware instructors' good ideas.

[Runaway Gun]

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]

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

Just curious is all.....

Cheers

[421dog]

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]

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]

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]

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]

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]

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]

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]

+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]

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]

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]

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.

[deja vu]

iAnother 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.

With all due respect your statement re flying an MU2 away from just off the ground with an engine failure is not correct. Certainly it is going to take a significant amount of training and a few things going for you. I was very fortunate to be sent to Flight Safety in Houston for an MU2 refresher course after having accumulated around 100 hours on the Marquise model following a very basic endorsement. That was 40 years ago and I still remember about 8 hours of the sim part of the course was all s/e work, including failures at TOSS , numerous sim resets later survival was achieved. Sadly not everyone got to go to Flight Safety but I did manage to demonstrate the same at altitude during endorsement of others.

I am a little confused about your references to V1 and Vr in regard to the MU2.

[Mach E Avelli]

It has been many moons since I flew the MU2 and I never had the benefit of simulator on that type, so I will defer to those with greater experience on type.
My point is that some manufacturers of light turbines recommend rotation speeds that are sometimes implied to be equal to a V1, when in fact they are such thing. In fact using the term Vr is something of a misnomer too, as by definition Vr can only be equal to, or greater than V1.
The MU2 was touted as being semi STOL, rough field capable and was indeed a good bush aeroplane in the right hands, but the big split between recommended ‘unstick’ or Vlof (more appropriate terms?) and blue line meant there was a short period when you could be airborne but seriously compromised if an engine failed.

[Centaurus]

but the big split between recommended ‘unstick’ or Vlof (more appropriate terms?) and blue line meant there was a short period when you could be airborne but seriously compromised if an engine failed.

That short period after airborne and attaining blue line speed (usually about 10 seconds) applies to many light piston and turbo prop twins.

The RAAF had that problem with the introduction of twin jet aircraft like the Canberra bomber and Meteor fighter. Depending on weight typically the Canberra had a recommended lift off speed of 110 knots and a safe asymmetric speed of 160 knots at full load. The Meteor was similar. These numbers are off the top of my head and from memory so could be inaccurate.

Either way there could be a 40-50 knot spread between recommended lift-off speed and where, if an engine failed, the pilot had to make a decision to either reduce power on the live engine to help maintain rudder effectiveness (directional yaw) and hope the aircraft could still climb out albeit reduced rate of climb - or running out of rudder and risk rolling on its back. That spread of speeds was known as the dead man's gap.

The only other solution if an engine failed below single engine ‘safety’ speed was to force land straight ahead under control and pray there were no obstacles.

In the case of GA light twins, the spread (or dead man's gap) between POH lift-off speed and Blue Line is usually around 10-15 knots. You either accepted the miniscule risk of losing an engine inside those few seconds between airborne and single safety speed or you pulled up stumps and went home. .

So much depends on the flying skill of individual pilots and their technical knowledge of the single engine performance of each particular aircraft they flew.

Some pilots had their own personal ideas such as holding the aircraft on the runway until lifting off at single engine safety speed or ‘Blue Line’ speed. That could bring in other factors such as a high speed abort if an engine packs up just as you reach blue line while still on the runway. Examples are does the aircraft have anti-skid brakes? Is the runway wet therefore less braking efficiency?

Faced with so many variables some pilots may prefer to stick with POH recommended VR or lift off speed and accept that, unlike airliners certified to have a V1 and Vr capability, there will always be a window of indecision of a few seconds until reaching airborne blue line speed.

[deja vu]

It has been many moons since I flew the MU2 and I never had the benefit of simulator on that type, so I will defer to those with greater experience on type.
My point is that some manufacturers of light turbines recommend rotation speeds that are sometimes implied to be equal to a V1, when in fact they are such thing. In fact using the term Vr is something of a misnomer too, as by definition Vr can only be equal to, or greater than V1.
The MU2 was touted as being semi STOL, rough field capable and was indeed a good bush aeroplane in the right hands, but the big split between recommended ‘unstick’ or Vlof (more appropriate terms?) and blue line meant there was a short period when you could be airborne but seriously compromised if an engine failed.
Well yes, it was a dogs breakfast of misinformation.
We know that V1, Vr and V2 give guarantees, at least on paper, of achieving certain abilities to stop, go and climb out at required gradients and are calculated for each and every take off and for a current set of conditions. Aircraft below 12,500lbs (5700kgs) however had only one guarantee and that was at sometime it had been demonstrated that it could achieve a 1% climb gradient at 5000' at ISA with one engine inoperative to achieve certification. P charts were provided to calculate take off and landing distances with all engines operating.
In the case of the MU2 many speeds were published like Vs, Vmca, TOSS and Blueline. TOSS (110kts) only meant acceptable margins above VS and Vmca for T/O configuration, it didn't mean much else. Blue line speed (152kts) was best climb speed, clean, at Max TOW, it didn't mention best rate or best angle of climb

It was unfortunate that sim training was not easily available for all MU2 pilots, at least once. An new MU2-B-60 was over a $1m USD in 1980, insurance around $40K per year yet $ 3000 was considered too much to send a pilot off for a week to Flight Safety, it would have been the best investment operators could make. Thats GA though, I was in it for long enough.

Centaurus, I am not sure of certification requirements for military aircraft. But I imagine an ejector seat negates any serious considerations.

[machtuk]

That short period after airborne and attaining blue line speed (usually about 10 seconds) applies to many light piston and turbo prop twins.

The RAAF had that problem with the introduction of twin jet aircraft like the Canberra bomber and Meteor fighter. Depending on weight typically the Canberra had a recommended lift off speed of 110 knots and a safe asymmetric speed of 160 knots at full load. The Meteor was similar. These numbers are off the top of my head and from memory so could be inaccurate.

Either way there could be a 40-50 knot spread between recommended lift-off speed and where, if an engine failed, the pilot had to make a decision to either reduce power on the live engine to help maintain rudder effectiveness (directional yaw) and hope the aircraft could still climb out albeit reduced rate of climb - or running out of rudder and risk rolling on its back. That spread of speeds was known as the dead man's gap.

The only other solution if an engine failed below single engine ‘safety’ speed was to force land straight ahead under control and pray there were no obstacles.

In the case of GA light twins, the spread (or dead man's gap) between POH lift-off speed and Blue Line is usually around 10-15 knots. You either accepted the miniscule risk of losing an engine inside those few seconds between airborne and single safety speed or you pulled up stumps and went home. .

So much depends on the flying skill of individual pilots and their technical knowledge of the single engine performance of each particular aircraft they flew.

Some pilots had their own personal ideas such as holding the aircraft on the runway until lifting off at single engine safety speed or ‘Blue Line’ speed. That could bring in other factors such as a high speed abort if an engine packs up just as you reach blue line while still on the runway. Examples are does the aircraft have anti-skid brakes? Is the runway wet therefore less braking efficiency?

Faced with so many variables some pilots may prefer to stick with POH recommended VR or lift off speed and accept that, unlike airliners certified to have a V1 and Vr capability, there will always be a window of indecision of a few seconds until reaching airborne blue line speed.

thats pretty much what I said " no mans land" for a few kts.