Silly Question Time

[Big_Johnno]

This may sound like a silly question but do Turbine helicopters the likes of a Jetranger have an ignition KEY? i know they on Bell 47's and R22/R44's piston engines but i have never seen one on a turbine panel. Theoretically if there isn't one wouldn't this mean someone could come along and start one up and just fly away and surely on such an expensive piece of equipment you would want some sort of ignition disabling device to prevent theft.
John
P.S I told you it was a silly question!!!!!!!!

[Giovanni Cento Nove]

AFAIK The following have an "ignition key". Although it only disables the start circuit.

MD 500C, D, E, F, 520N, 600N.

[Oogle]

Not a silly question at all.

I often wondered that before I got my first turbine endorsement.

Most turbine helicopters do not have an ignition key aside from the Hughes/MD range mentioned above.

Basically, you jump in, turn on the battery and hit the starter button and away you go. The only thing that stops hoons running away with your aircraft is the door lock (that requires a key). Most pilots may disconnect the battery if the aircraft is left un-attended.

You may have remembered some years ago a JetRanger being started up by some idiots in Orange, NSW after breaking into it. I think he actually got it started and got into the "hover" before it all turned pear shaped for him. I think the aircraft was the Electricity Commission machine.

Hope that helps. :ok:

[Big_Johnno]

Thanks All for the Info. Come to think of it i do remember Larry Hagman in Deadly Encounter turning on an ignition switch when he fired up the Hughes 500 at the start of the Movie. Great Movie if anyone hasn't seen it, well worth a look.
Regards John

[Farmer 1]

I agree with Oogle. There is no such thing as a silly question, only silly answers. Which is my excuse for asking the following question - of a technical nature. It is one I have wondered about for an inordinate length of time, and one I should have asked some clever person many years ago. Please forgive me, Johnno, if I borrow your thread a moment.

On a helicopter with more than two main rotor blades, some kind of arrangement is made to allow the blades to drag backwards and forwards during flapping. But what about aircraft with two blades? The blades flap up and down, causing a shift of c. of g. towards the centre, thereby inducing a tendency for the blades to increase RPM. But they do not have any drag hinges.

So, what happens? It seems to me that on each revolution the blades pass through two cycles of increasing and decreasing RPM. If that is correct, the variations in RPM are passed through the mast down to all that lot down below, to use a technical term. I don't like to think of gearboxes and engines and things having to cater for these rapid fluctuations.

I really would appreciate the definitive answer.

[Fatigue]

Hey there big-johnno,...the Bell 206's (TH-67) that the U.S. army use to teach new recruits does have to have an ignition key in to start it...just ask all the new recruits who fail to start the aircraft because they forgot to put the key in the ignition:p !!!! Just depends on the operator if he wants to install one or not!

[ShyTorque]

Someone stole a US Army helicopter a long while back and landed it on the lawn by the White House. Now ALL the later ones have ignition keys in that part of the world.

Be advised though, now you know the answer we are going to have to kill you. :}

Sorry, but it is strictly necessary. :suspect:

;)

[Cron]

That's a bit harsh ST .. could it be commuted to 'sent to bed with no tea' ..

[Whirlygig]

Cron,

Not really 'cos you'd still have the knowledge and could sell the military secret to the Russians!

Mind you, don't see why it couldn't be commuted to brain erasing; one of those metal skull caps with lots of wires - I seen 'em on the telly!

Cheers

Whirls

Farmer1 - Shawn Coyle's book contains the answer!

[Above Datums]

No ignition key on the 412. I think the reasoning is that if you get past the armed guards, break into the hanger, get the thing on dispersal, figure out how the thing starts and manage to do ALL the functionals and PACs then youve earnt it!!!


;)

AD

[Gerhardt]

Doesn't usually require a contraption for me. Just a few pints.

[PPRUNE FAN#1]

None of the Bell 47's I've ever flown had a key-type mag switch. They all had that old design that was probably invented for airplanes in the 1930's. I'd imagine that as those old switches bite the dust, people replace them with modern key-type switches.

No turbine helicopter I've ever flown needed a key. Nor do airliners, turboprop airplanes or business jets need an ignition key.

[morris1]

md 902... has a "ignition" key, right of console.. comes with a spare too, just in case..

and yes... thefts do happen...
http://www.sheffieldtoday.net/ViewArticle2.aspx?SectionID=58&ArticleID=291981

[platinumpure]

The reason that lead and lag hinges are not required on most 2 bladed rotor systems is because these systems are usually underslung. Therefore when a blade flaps up it allowed to keep its distance from the mast. Therefore the center of mass doesn't really move to much closer to the center of rotation.

It would be easier to understand if I drew a diagram, however I just got back from from a long days flying and I'm trousered mate.

Hope this points you in the right direction.

Do a search on underslung rotor systems.


Cheers.

[Thud_and_Blunder]

Boeing's VTOL twin-jets (or at least the RAF versions up to HC2)have keys too - same (US Army experience) reason as given above.

Best idea is probably to put the key in, turn it to "on" then break off the round bit.

[7balja01]

another silly question,

what is the start up procedure for a heli (IM NOT A PILOT)

I flew a simulator once, and all it required was for me to hop in, start the engines, bring it up to 50% on rotor pitch bar thingy, level it, and take off!

is that the procedure? It sounds fairly simple.

jacob.

[Farmer 1]

For Plats Thanks very much for that. I must admit to not remembering the term "underslung" used in this context. So, that's something I've learned today.

For Whirls Thanks to you also. I just might put that book on my Christmas list.

Thanks again, both.


For Jacob On a piston-engined helicopter, you press the starter, and it usually starts. Quite simple, really.

On a modern, sophisticated helicopter with all the bells and whistles, you press the starter, and it usually starts. Quite simple really.

On the rest, you press the starter and spend the next thirty seconds or so adusting the throttle in order to prevent the engine temperature getting too high or too low, making sure the compressor is accelerating normally, ensuring rotor RPM is increasing, monitoring engine oil pressure, hydraulic oil pressure, transmission oil pressure, battery voltage, warning panel lights, making sure no one walks into or out of the rotor disc, deciding whether or not to ignore pax tapping you on the shoulder. Quite complex, really.

Seriously, it is a complicated procedure, and I still marvel at the many very clever people who, over the years, have designed and developed these engines which manage to start correctly virtually every time.

[Big_Johnno]

Morris1, That is a very leanient sentence, a $200 fine for over $12,500 worth of damage. just goes to show there is no justice in your part of the world either. The courts are too leanient. should have been made to pay back the FULL amount.

[morris1]

yep.. thats about the measure of it.
Shouldve gone to straight to jail. Whats the point fining him something he wont pay.
Jails too full ?? build more jails !!
Whats wrong with that.? Sooner or later all the criminals will be behind bars and we can all get on with life.. AND leave our keys in our aircraft..;)

[Blackhawk9]

One of the reasons the US Army put keys in there Helos is not against theft but crews accidently taking the wrong Helo!! If you have seen the flight line at FT Rucker you would understand ,row upon row of Helos, in the past crews have left the flightline and inadvertantly got into the wrong Helo, so give the crew a key and if the power doesn't come on you may be in the wrong a/c , try again!!

[BossEyed]

I'd heard it said that there were only a small number (one?!) of different keys available for each type in the US Army fleet.

And whilst I'm spreading potential urban legends, it's always been my understanding that ShyTorque's story about helicopter theft is correct; but that it gets better.

The story goes that an unrated Huey crewchief (during the time of the Vietnam war) became most disgruntled, and so stole his bird to take it to the White House lawn and have his issues out, mano-a-mano, with The President.

This didn't go down well, as you'd imagine, hence the requireemnt in future designs for a key.

When the aircraft are not in use, they keys are held securely by... the crewchief. :ok:

Right then US Army types - this is now your chance to tell me that one of favourite anecdotes is wrong. :D

[TechHead]

Apache Longbow has an ignition key and a canopy door key. The ignition key, I believe, is to avert unwanted engine starts since the whole process is close to fully automatic. Canopy door key of course is to try to avert theft.

That said, if one really wanted to gain access you could blow the canopy from outside and climb in the hole. Hot wiring the MIK switch is easy. You could steal a ride, but it's going to get a bit breezy at about 30 KTAS.

Got a great story about a crew chief who started an engine recently but I'll have to wait a couple of months before I share it.