Can Chinooks auto-rotate?
Purveyor of Egg Liqueur to Lucifer
amanoffewwords,
I see you're not from the Midlands!!!!
Max Con is obviously completely ignorant in the operation of Police Helicopters.
"how nice it was that they turned up completely unexpected"
Sorry, we'll give the crims a phone call in future so they can make a getaway!
"how the crew amazed the crowd with such skill at low level"
It's not difficult to impress the unknowing.
"how you were previously unaware that a rotor craft could be manoeuvred in such extreme ways"
Well, I hope you have now learnt from the experience! Join us on our next inner city pursuit!
I'll just get this hook out from my cheek!!
By the way, it's not a 'loop', but a low speed route reversal!!
wg_13,
Isn't the torque value based on the gearbox limitation and not the engine!!! Even at a 100% TQ, isn't the engine still only working at about 60% of its capability. It's a powerful engine the Gem!
The Nr & Nf needles are set at '107% Nr' as that is the result of the SSL selection after start up. Bonk tuning?
As your pics show, at 120kts the SSL should be adjusted to give 104.8%. Primarily, isn't this to give 104.8%NR in order to reduce airframe vibration and therefore a smoother flight?
I see you're not from the Midlands!!!!
While I'm here, here's another that was buzzing over me:
Max Con is obviously completely ignorant in the operation of Police Helicopters.
"how nice it was that they turned up completely unexpected"
Sorry, we'll give the crims a phone call in future so they can make a getaway!
"how the crew amazed the crowd with such skill at low level"
It's not difficult to impress the unknowing.
"how you were previously unaware that a rotor craft could be manoeuvred in such extreme ways"
Well, I hope you have now learnt from the experience! Join us on our next inner city pursuit!
I'll just get this hook out from my cheek!!
By the way, it's not a 'loop', but a low speed route reversal!!
wg_13,
Isn't the torque value based on the gearbox limitation and not the engine!!! Even at a 100% TQ, isn't the engine still only working at about 60% of its capability. It's a powerful engine the Gem!
The Nr & Nf needles are set at '107% Nr' as that is the result of the SSL selection after start up. Bonk tuning?
As your pics show, at 120kts the SSL should be adjusted to give 104.8%. Primarily, isn't this to give 104.8%NR in order to reduce airframe vibration and therefore a smoother flight?
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Slow day at the office SS?
I was attempting to keep it simple mate.
If you wish to have a limitations quiz, give me a shout and I'll send one over.
(I'll make sure you get above 60% this time (30% real time)) 
It is but we work out single eng perf based on PPI not gearbox.
Tell the rest of the bonk tuning criteria then?? C'mon, you'll not get away that easily!
I was attempting to keep it simple mate.
If you wish to have a limitations quiz, give me a shout and I'll send one over.
(I'll make sure you get above 60% this time (30% real time))
It's a powerful engine the Gem!
Tell the rest of the bonk tuning criteria then?? C'mon, you'll not get away that easily!
Purveyor of Egg Liqueur to Lucifer
Slow day at the office SS?
memo to self: must remember passwords for tax return, then I won't be drawn towards PPRuNe !
As for the quiz, if you can get one here for Friday in time for my OPC that would be great. It would be the correct type I trust!?
Thanks for the results, I didn't know back then that they were that low! With 'Above Average' gradings back then, I wonder what I would get if I scored higher in the MPQ!
By the way, I never got the last question on each MPQ paper corect.
What 'was' the telephone number for Aviation Standards at M.Wallop? I do hope the questions are more relevant these days!
we work out single eng perf based on PPI not gearbox.
SS
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Papers in the post
Forgotten how and why we do a PPI already, Sid??
You've still not furnished me with the rest of the bonk setting criteria
QHI's.....c*"ts the lot of 'em!
But surely that is still a transmission torque limitation!!!
You've still not furnished me with the rest of the bonk setting criteria
QHI's.....c*"ts the lot of 'em!
wg13,
Cu*ts are useful and pleasant to be around, aren't they?
Sid,
What's a tax return?!
Cu*ts are useful and pleasant to be around, aren't they?
Sid,
What's a tax return?!
Purveyor of Egg Liqueur to Lucifer
It seems then wg, that my memory is fading faster than a cat can lick it a$$!!
When working out the single engine performance figures, I always used to refer to the charts in the back of the ODM. The figures were based on Temp/Press/Wt. At no time did I go to the BATs office and get the latest PPI figures.
These days, we do a PAC (Power Assurance Check) daily, and still when working out the figures for Cat A Ops, do not go and check the daily PAC sheets. The Performance data charts still only needs a combination of Temp/Press/Weight to give me the required values.
Perhaps it is you that doesn't know why you do a PPI in the first place!
SS
Thud,
Time for you to come home, the Sun must be getting to you!!
SS
When working out the single engine performance figures, I always used to refer to the charts in the back of the ODM. The figures were based on Temp/Press/Wt. At no time did I go to the BATs office and get the latest PPI figures.
These days, we do a PAC (Power Assurance Check) daily, and still when working out the figures for Cat A Ops, do not go and check the daily PAC sheets. The Performance data charts still only needs a combination of Temp/Press/Weight to give me the required values.
Perhaps it is you that doesn't know why you do a PPI in the first place!
SS
Thud,
Time for you to come home, the Sun must be getting to you!!
SS
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Power Assurance Check
So you wouldnt use the PPI figures from the 700 to establish where to start on the graphs then? Remember all the different graphs relating to 96% PPI (clean etc), 98% PPI (Clean etc), 100% PPI (blah...).
At no time did I go to the BATs office and get the latest PPI figures.
Surely the performace of the engine (well, since its last PPI) is quite relevent to what we could expect the engine to produce should the other donk stop?
(........1013 set, S+L, CAC out, friction on, ECL brief, 1 back to check 2, pull to 100 %, allow to settle, read OAT, Alt, NR, TQ, T6, NH....blah..... See if its T6, NH or NR droop limited?? REMES calculate to give the errr Power Performance Index so that we can calculate the errr Sin Eng Perf!!) Jog any memories, Sid?
My, you have been away too long!
When working out the single engine performance figures, I always used to refer to the charts in the back of the ODM. The figures were based on Temp/Press/Wt. At no time did I go to the BATs office and get the latest PPI figures.
Purveyor of Egg Liqueur to Lucifer
Hmmm...shouldn't that have been done by the end of September?
And that gives you the limitation for the gearbox??
Running parrallel on this thread, Torque limitations are based on the transmission are they not? An engine can easily overtorque a transmission.
I guess when I said, "At no time did I go to the BATs office and get the latest PPI figures" I must have been thinking about that cat licking its a$$. OK, wrong again, sorry!
Now was that anti-icing and cabin heating off or not? What if I have anti-icing off and cabin heating on? AFCS Height hold disengaged or not?
Anyway, I still stand by "When working out the single engine performance figures, I always used to refer to the charts in the back of the ODM. The figures were based on Temp/Press/Wt." But must add, the chart used was decided by the PPI results found in the 700. But isn't that just for finding MinSELF?
Do/Did you feel safe in an aircraft giving you 94% PPI?
'Above average' eh?
You never did make PSI did you? Only now by default!
SS
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Apology accepted.
I guess its a similar thing for most twin engined helis. But with the Lynx it goes for the most current figure as opposed to what the manufacturer spec says it should be? Is the PAC figure a fixed book figure?
Yes quite true. Thats why we have a TQ guage. TQ limitations are set in stone. But with a low PPI engine or a 'bad performance day' there is no guarentee that the TQ limit will be reached before the MSELF. Hot & High it will more than likely be the T6 or even the NH.
Think youve answered your own question.
More than.
As to your last question......YES! Cheeky git!
No, the PAC is a means for the pilot to determine, prior to take off, that each engine is capable of developing specification power!!
Running parrallel on this thread, Torque limitations are based on the transmission are they not? An engine can easily overtorque a transmission.
When working out the single engine performance figures
But isn't that just for finding MinSELF?
Do/Did you feel safe in an aircraft giving you 94% PPI?
As to your last question......YES! Cheeky git!
Purveyor of Egg Liqueur to Lucifer
One of those weeks, just trying to get the 3rd thing to go wrong, in order to reset everything.
(This thread seems to have done the trick!)
Thanks for the help________wg
SS________
Opening up to contradiction on different types here, but I think that the PAC way keeps everything 'tidy'. As mentioned before, the PAC ensures that the engines are capable of developing specification power, if they are producing within spec then all is well. It is a check afterall, as opposed to an index figure.
The check is a monitor for power trends and should a trend develop, indicating power loss, then it is investigated further from that point. Rather than having lots of starting pages (moving posts!!), ie 104%, 100%, 94% anti ice & cabin heating on or off, sand filters fitted, etc.
Wouldn't it be easier in the Lynx to work off one set of charts, lets say the 94% figure, and if you have 104% or 100% PPI, bonus! ?
How about also a system where should an engine fail, the cabin heating (and air conditioning!) automatically switches off in order to utilise maximum power from the remaining engine, with an override for use when back in a safe OEI condition?
Maybe on FLynx!!!
SS exits stage left ________________________
(This thread seems to have done the trick!)
Thanks for the help________wg
SS________
Is the PAC figure a fixed book figure?
The check is a monitor for power trends and should a trend develop, indicating power loss, then it is investigated further from that point. Rather than having lots of starting pages (moving posts!!), ie 104%, 100%, 94% anti ice & cabin heating on or off, sand filters fitted, etc.
Wouldn't it be easier in the Lynx to work off one set of charts, lets say the 94% figure, and if you have 104% or 100% PPI, bonus! ?
How about also a system where should an engine fail, the cabin heating (and air conditioning!) automatically switches off in order to utilise maximum power from the remaining engine, with an override for use when back in a safe OEI condition?
Maybe on FLynx!!!
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How about also a system where should an engine fail, the cabin heating (and air conditioning!) automatically switches off in order to utilise maximum power from the remaining engine, with an override for use when back in a safe OEI condition?
There are even more graphs in the back now, Sid. I think the reason why there is so many is firstly, we operate in slightly more varied environments than was the case 15 or so years ago. I'm talking hot.
And secondly, if we just went for the lowest, it may take away a potential landing site when in fact it could be made. Ie. Taking the lowest PPI, 94%, we may come up with a MSELF of 50 knots (not impossible in some theatres). Having a MSELF as high as that would also give us quite a high run on speed (prob over 30kts). This may push us into a decision to go elsewhere if we didnt have a suitable length or surface of area to run on to. You may think 'well, thats working well on the safe side'. True it is but the greater array of figures and calcs means that we can more accuratly get a realistic figure. Ie, more flexibility.I'm guessing in the civy side, the PAC gives you a greater safety margin hence it being a set figure?
Maybe on FLynx, I'll let you know.
