Takeoff Technique For Cessna's
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Swh, don, I agree with all thats been said, the company I work for base V1 on an optimum flap setting that is arrived at using an assumed A/c Mass, pressure alt, OAT, and TORA(JAA..Take off run available). All things being equal V1 must always be greater than or equal to VMCA..or else we(who I work for) are operating illegally (outside our Ops manual spec.
I also thought VMCG was a function of A/C mass therefore it should be higher than V1 in any case.
I guess my point is that I prefer to use the excess thrust if I need it
Oh and ya gotta love the Kingair!..PT6 heaven
I also thought VMCG was a function of A/C mass therefore it should be higher than V1 in any case.
I guess my point is that I prefer to use the excess thrust if I need it
Oh and ya gotta love the Kingair!..PT6 heaven
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haughtney1,
mate might be time to put the golf clubs down and pick up some of those old perf manuals floating around the place. Can't fault you for trying to help some one out, but this stuff can be confusing enough anyway without adding to it.
As i understand it (and i am no expert) the position of the mass in relation to the rudder, not the mass itself, is the thing with Vmcg, and Vmcg is always less than V1. Pretty hard to catch the schwiing if Vmcg is greater than your V1.
Until it flips you on your back cause you have run out of boot and it kills you. You may not always be allowed/able to use this excess thrust, as alluded to in previous posts. It depends on how you crunched the numbers to get airborne in the first place.
Back to the original thread,
We use 80kts as an incapacity check to make sure the old fart next to us hasn't carked it, otherwise you may be checking out haughtney1 on the 10th tee shortly after calling V1 rotate. Most glass types will flag an airspeed disagree pretty quickly (5 kt diff for > 5 secs on our type). Which gives plenty of time as it takes about 15 secs to get to 80kias. Fark nose why you would call 40 kts in a vfr bugsmasha, they fly fine as chuck said without it. Most people will only kill themselves when they notice it missing, but flew fine up until then.
mate might be time to put the golf clubs down and pick up some of those old perf manuals floating around the place. Can't fault you for trying to help some one out, but this stuff can be confusing enough anyway without adding to it.
I also thought VMCG was a function of A/C mass therefore it should be higher than V1 in any case.
I guess my point is that I prefer to use the excess thrust if I need it
Back to the original thread,
We use 80kts as an incapacity check to make sure the old fart next to us hasn't carked it, otherwise you may be checking out haughtney1 on the 10th tee shortly after calling V1 rotate. Most glass types will flag an airspeed disagree pretty quickly (5 kt diff for > 5 secs on our type). Which gives plenty of time as it takes about 15 secs to get to 80kias. Fark nose why you would call 40 kts in a vfr bugsmasha, they fly fine as chuck said without it. Most people will only kill themselves when they notice it missing, but flew fine up until then.
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Well done Bloggs..you passed the test..
quick question....if VMCG(ground) is less than V1..what happens when you lose an engine above VMCG and below V1?
And your referring to VMCA(airborne) when you talk about lacking rudder authority..which incidentally should be less than V1, and less than or equal to VMCG at MTOM. which is why transport catagory a/c are performance limited on this basis i.e. it is well understood and hence the numbers are crunched in that fashion. Orrrr else the plane in question could never be certificated and operated as a public transport a/c.
Unlike many light piston and T/P twins.
I agree can be confusing...but thats my understanding.
P.S. I need all the practise I can
quick question....if VMCG(ground) is less than V1..what happens when you lose an engine above VMCG and below V1?And your referring to VMCA(airborne) when you talk about lacking rudder authority..which incidentally should be less than V1, and less than or equal to VMCG at MTOM. which is why transport catagory a/c are performance limited on this basis i.e. it is well understood and hence the numbers are crunched in that fashion. Orrrr else the plane in question could never be certificated and operated as a public transport a/c.
Unlike many light piston and T/P twins.
I agree can be confusing...but thats my understanding.
P.S. I need all the practise I can
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haughtney1,
as you yourself would have briefed hundreds of times, you close the thrust levers, disconnect the autothrottle, make sure the speed brakes have deployed, select reverse on the good engine and let the autobrake bring you to a halt (or max manual braking as required) maintaining the centre line. Vmcg is always less than(or at most equal to) V1, as once you are above Vmcg you can control the aircraft directionally with the rudder alone (have another look at the definition, i think you have it arse about). Prior to V1 you are interested in Vmcg as you aren't (technically anyway) going to get airborne, at or above V1 you will take it into the air, and then you want Vmca to be less than Vr.
What i am refering to, as did donpizmeov and others, is the case when you derate (say you have a 26k engine and you derate and use performance for a 20k, this is different to an assumed temp thrust reduction). Then if you have a problem AT OR ABOVE V1, you continue and if you were to advance the thrust levers past the 20k TOGA bug and beyond, to the 26k thrust limit (firewall) you are going to start to have directional problems as the thrust you are introducing is inexcess of what you used to calculate your takeoff performance figures for that weight. As others have said it is not necessary as you have adequate thrust even at the calculated setting, or if in doubt about terrain clearance, the TOGA thrust for the calculated derate, not full welly. Have another look at the previous posts, they explain it better than me anyway.
Not having a go at you here, as this stuff does slip from the memory if you don't keep looking at it and i am certainly no expert. (as others may point out when they read the above, which i hope is correct)
if VMCG(ground) is less than V1..what happens when you lose an engine above VMCG and below V1?
What i am refering to, as did donpizmeov and others, is the case when you derate (say you have a 26k engine and you derate and use performance for a 20k, this is different to an assumed temp thrust reduction). Then if you have a problem AT OR ABOVE V1, you continue and if you were to advance the thrust levers past the 20k TOGA bug and beyond, to the 26k thrust limit (firewall) you are going to start to have directional problems as the thrust you are introducing is inexcess of what you used to calculate your takeoff performance figures for that weight. As others have said it is not necessary as you have adequate thrust even at the calculated setting, or if in doubt about terrain clearance, the TOGA thrust for the calculated derate, not full welly. Have another look at the previous posts, they explain it better than me anyway.
Not having a go at you here, as this stuff does slip from the memory if you don't keep looking at it and i am certainly no expert. (as others may point out when they read the above, which i hope is correct)
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Actually I do have it face about arse
(stems from me mistakenly thinking that VMCG included aerodynamic controls)
oh dear........haha...hey at least you were nice about it
and whats with these baby 26K engines??
goin back under my rock.
The really sad thing is..thinking about this in my bloody sleep!
(stems from me mistakenly thinking that VMCG included aerodynamic controls)oh dear........haha...hey at least you were nice about it
and whats with these baby 26K engines??
goin back under my rock.The really sad thing is..thinking about this in my bloody sleep!
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Close my eyes, Open the throttle and I just hold everything "just so" and when the bumps and rumbles stop and it gets smooth , I open my eyes!
works every time
compliment to Bloggs for a gentle and erudite explaination, and not the typical stepping on toes, nice post , not that I understand a word of it however.........
works every time
compliment to Bloggs for a gentle and erudite explaination, and not the typical stepping on toes, nice post , not that I understand a word of it however.........
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7gcbc,
thanks, wouldn't do it on the flight deck, why do it here. Best result all round if you can learn something, and i might have too if i didn't have it right.
atyourcervix73,
i didn't, after all its not easy being a kiwi.
(don't mention the rugby) 
not the typical stepping on toes
atyourcervix73,
i didn't, after all its not easy being a kiwi.
(don't mention the rugby)
Grandpa Aerotart
and then poled forward to avoid whacking the end of said strip with tail of said aeroplane...IAS? Merely of academic interest...and not that many of us were academics
And no kiddies...we're not joking
And no kiddies...we're not joking
Man Bilong Balus long PNG
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Tinpis and Chuckles; Interesting that you gentlemen should mention the subject of those PNG strips..
Only once did I ever do what you described in your previous posts on this page. T'was at Kamulai or Sopu, can't remember now but I was even sufficiently possessed by whatever demon to yell "Banzai" at the top of my voice as we shot off the edge of the strip!!
Caused a severe sense of humour failure amongst some of my pax as well!!
And I would'nt have changed anything for quids!!!
You only live twice. Once when
you're born. Once when
you've looked death in the face.
Only once did I ever do what you described in your previous posts on this page.
T'was at Kamulai or Sopu, can't remember now but I was even sufficiently possessed by whatever demon to yell "Banzai" at the top of my voice as we shot off the edge of the strip!!Caused a severe sense of humour failure amongst some of my pax as well!!
And I would'nt have changed anything for quids!!!
You only live twice. Once when
you're born. Once when
you've looked death in the face.
Grandpa Aerotart
Sometimes, as I get older and marginally smarter, I wish I could only remember doing it once
Tinny do you remember/was it built in your day a strip called Nomane. Just east along the Wahgi from Diriman. Heading east from Diriman it was actually the second strip on the right...From Goroka straight through the kaw Kaw Gap, across the eastern end of Mt Elambari and on the south side of the Wara Wahgi?
350m long, 19m wide, the first 100 or so reasonably flat (maybe 3%) and then around a 20 degree corner and then up to about 15% with a transverse slope of around 5% and a deep barret either side of the strip. Typical of PNG the side slope was reverse camber.
It was a RLA up to 87 and then, along with all the god squad Restricted Landing Areas, it was derestricted and open slather for us heathens.
100m in on the right was a bridge over the barret into the parking bay just wide enough for the wheel track of a Twotter..maybe...not sure I ever actually saw a Twotter there, maybe once...usually just me in a C185/Islander and sundry god squad in their Turbo 206s.
Terrible windy place from late morning....strong quartering tailwind from the right on takeoff...given that you had to turn left during the takeoff roll and the strips transverse slope was down to the right the wind sorta didn't help much. Threshold elevated about 2000' above a gorge. Elevation about 6000' up a 9000' ridge....BIG descending air on short finals!!!
Remember dat one?
Cannot say as I remember ever looking at the IAS on takeoff there...especially the time I started my takeoff roll from abeam the parking bay in Clyde Cessna's finest.
Tinny do you remember/was it built in your day a strip called Nomane. Just east along the Wahgi from Diriman. Heading east from Diriman it was actually the second strip on the right...From Goroka straight through the kaw Kaw Gap, across the eastern end of Mt Elambari and on the south side of the Wara Wahgi?
350m long, 19m wide, the first 100 or so reasonably flat (maybe 3%) and then around a 20 degree corner and then up to about 15% with a transverse slope of around 5% and a deep barret either side of the strip. Typical of PNG the side slope was reverse camber.
It was a RLA up to 87 and then, along with all the god squad Restricted Landing Areas, it was derestricted and open slather for us heathens.
100m in on the right was a bridge over the barret into the parking bay just wide enough for the wheel track of a Twotter..maybe...not sure I ever actually saw a Twotter there, maybe once...usually just me in a C185/Islander and sundry god squad in their Turbo 206s.
Terrible windy place from late morning....strong quartering tailwind from the right on takeoff...given that you had to turn left during the takeoff roll and the strips transverse slope was down to the right the wind sorta didn't help much. Threshold elevated about 2000' above a gorge. Elevation about 6000' up a 9000' ridge....BIG descending air on short finals!!!
Remember dat one?
Cannot say as I remember ever looking at the IAS on takeoff there...especially the time I started my takeoff roll from abeam the parking bay in Clyde Cessna's finest.
Cloud Cutter. You wrote:
In "most" manufacturer's POH there is no mention of "holding the weight off the nosewheel". It is yet another GA myth (there are lots of them).
If you are taking off from a rough or soft field the C152 /C172 POH does state that the aircraft should be lifted off the ground in a slightly tail low attitude. On a normal take-off the POH states that at 50 knots IAS, lift the nosewheel. This of course is the actual lift off speed listed in the Takeoff Distance Chart. It has nothing to do with the commonly held GA myth of "taking the weight off the nosewheel." The latter may lengthen the take off run due to extra drag and thus invalidate the take off performance chart.
You also mention that "in most lighties you don't need a certain speed....it will just get airborne when it wants to".
There are at least 150 different "lighties". Do you apply your own general fits all take off technique for each type you fly - thus ignoring the manufacturer's POH recommenadtion for each type?
For normal takeoffs, the Cessna POH's state a specific airspeed to lift off in order to meet the takeoff certification performance requirements. Believe me, some of these GA myths are very convincing - particularly if your instructor has hammered them into you as God's Own Truth. Best stick to the speeds and advice in the manufacturer's POH. Saves you grief with the lawyers if you stuff up and bust the aeroplane one day.
As for the 'rotate' speed. In most lighties you don't really need a certain speed, just hold the weight off the nosewheel and somewhere around 40-50 knots raise the nose to climb attitude - the aircraft will get airborne when it wants to. It's not a heavy jet and not designed to be kept on the ground to build up speed
If you are taking off from a rough or soft field the C152 /C172 POH does state that the aircraft should be lifted off the ground in a slightly tail low attitude. On a normal take-off the POH states that at 50 knots IAS, lift the nosewheel. This of course is the actual lift off speed listed in the Takeoff Distance Chart. It has nothing to do with the commonly held GA myth of "taking the weight off the nosewheel." The latter may lengthen the take off run due to extra drag and thus invalidate the take off performance chart.
You also mention that "in most lighties you don't need a certain speed....it will just get airborne when it wants to".
There are at least 150 different "lighties". Do you apply your own general fits all take off technique for each type you fly - thus ignoring the manufacturer's POH recommenadtion for each type?
For normal takeoffs, the Cessna POH's state a specific airspeed to lift off in order to meet the takeoff certification performance requirements. Believe me, some of these GA myths are very convincing - particularly if your instructor has hammered them into you as God's Own Truth. Best stick to the speeds and advice in the manufacturer's POH. Saves you grief with the lawyers if you stuff up and bust the aeroplane one day.
Grandpa Aerotart
Centaurus.
Some of the 'myths' are indeed enfuriating but not all are rubbish. The 'holding' the weight off the nosewheel' one is a soft/rough field technique which is very valid. Particularly soft fields...I well remember doing a first landing at a newly 'finished' strip in PNG in order to declare it open. My usual mount was a C185 but it was in for a service so I went in a Turbo 206...lots of grunt me thinks..no worries. I very nearly didn't get airborne because of the nosewheel dragging through soft areas in the surface...and then I remembered holding the nosewheel off and managed to get airborne...the next day in the C185 (taildragger) was a doddle by comparison.
As to holding the weight off on long hard runways...or even shorter smooth runways and then rotating 'a little more' when approaching flying speed a letting the aircraft fly when it's ready?
Well why not?
I would suggest the little extra drag from a slightly deflected elevator is not significantly more than the drag from a nosewheel bearing a significant weight.
The ONLY single engined Cessna type I have not flown (built post 1960) is the C208 Caravan. The above technique works well in every one. In the 180/185 series raising the tailwheel a little a letting it fly off worked too...wonderfully.
I have flown just about every piper single...ditto.
It works well in my Bonanza.
These are not FAR 25 certified aircraft and the performance graphs in the POH are all very interesting but, in my opinion, are not to be used to decide exact speeds and Tkoff/landing distances with a sharp pencil and then flown like you did in a 737.
What did you do in Tiger Moths when you learned. What about the Harvard and Mustang...I have flown the first a fair bit, the second a few times and I'd bet the Mustang was the same...raise the tailwheel a bit and away ya go....they fly when they are ready.
Some of the 'myths' are indeed enfuriating but not all are rubbish. The 'holding' the weight off the nosewheel' one is a soft/rough field technique which is very valid. Particularly soft fields...I well remember doing a first landing at a newly 'finished' strip in PNG in order to declare it open. My usual mount was a C185 but it was in for a service so I went in a Turbo 206...lots of grunt me thinks..no worries. I very nearly didn't get airborne because of the nosewheel dragging through soft areas in the surface...and then I remembered holding the nosewheel off and managed to get airborne...the next day in the C185 (taildragger) was a doddle by comparison.
As to holding the weight off on long hard runways...or even shorter smooth runways and then rotating 'a little more' when approaching flying speed a letting the aircraft fly when it's ready?
Well why not?
I would suggest the little extra drag from a slightly deflected elevator is not significantly more than the drag from a nosewheel bearing a significant weight.
The ONLY single engined Cessna type I have not flown (built post 1960) is the C208 Caravan. The above technique works well in every one. In the 180/185 series raising the tailwheel a little a letting it fly off worked too...wonderfully.
I have flown just about every piper single...ditto.
It works well in my Bonanza.
These are not FAR 25 certified aircraft and the performance graphs in the POH are all very interesting but, in my opinion, are not to be used to decide exact speeds and Tkoff/landing distances with a sharp pencil and then flown like you did in a 737.
What did you do in Tiger Moths when you learned. What about the Harvard and Mustang...I have flown the first a fair bit, the second a few times and I'd bet the Mustang was the same...raise the tailwheel a bit and away ya go....they fly when they are ready.
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I concur with Chimbu on that one Centaurus. Tried it several times in various aircraft in an unofficial capacity in my much younger days...leaving the nosewheel down and taking the weight off. Shorter take-off distance every time with the nosewheel off, and leaving it down on a strip with grass any longer than the centre of the MCG is almost dangerous. On a gravel strip, it helps get the prop that little further away from the stones and ruts have less impact. Doesn't make a great deal of difference on a sealed runway, but it still seems better than letting the nosewheel shimmy and shake.
Silly Old Git
No that was after my time Chuck.
I did go into a few of the god botherers strips in the Sepik.
And some pretty ****e awful excuses in the Markham and Kuka kuka country but that was in the lovely Turbo-Porter which didnt need an ASI
Once landed and got bogged in a 402 got everyone off and pushing.
After slowly moving down the strip got the nose off and away I went leaving some very mud be-splattered SLF to be picked up a couple of days later
Cant remember the name of the strip ..up the coast from Madang with a active volcano just offshore and a Betty bomber in the parking bay?
oh..oh..was it Awar?
I did go into a few of the god botherers strips in the Sepik.
And some pretty ****e awful excuses in the Markham and Kuka kuka country but that was in the lovely Turbo-Porter which didnt need an ASI
Once landed and got bogged in a 402 got everyone off and pushing.
After slowly moving down the strip got the nose off and away I went leaving some very mud be-splattered SLF to be picked up a couple of days later
Cant remember the name of the strip ..up the coast from Madang with a active volcano just offshore and a Betty bomber in the parking bay?
oh..oh..was it Awar?
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Centaurus
Sometime you have to use the old noggin and realise that the POH for these types of aircraft take a very simplistic view of what is invariably not a simple exercise.
When I was instructing, the only thing I drummed into my students was that you can't write a manual to cover every possible variable, and discretion is wise.
Sometime you have to use the old noggin and realise that the POH for these types of aircraft take a very simplistic view of what is invariably not a simple exercise.
When I was instructing, the only thing I drummed into my students was that you can't write a manual to cover every possible variable, and discretion is wise.