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Startup With Stop Rotor


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Just wonder if we can startup s-76 with the rotor stopped,why we can not be able to do the same with a Jranger a L or 222 or a 412?


Humm can't remember why!




The 206 has a sprague clutch and doesn't react well when held in position when the power rises.


As for the 61, We have a nice little thing called a DC Motor Generator that powers the hydraulics until the head is engaged. This Mo-gen allows us to carry out ground checks of the AFCS and hydraulics plus provides main gearbox luibrication until the head is spinning and power the accessory gearbox. As the Nr rises through 32%, the Mo-gen becomes a DC Generator.


The Sea King has a different system because of the complicated hydraulics in the folding head. I don't have my info on that here but I am sure that "Fully Articulated" or one of the other military guys here can help you on that.



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(1) Starting a Bell 47 or a Bell 206 in my world while the blades are forcefully being held would have and still will put one in imminent danger of having an 18" crescent wrench inserted forcefully into one's anal opening amongst the engineering crowd I associate/have associated with over the eons........sprague or no sprague clutch. It would also very likely engender a "fireside chat" with the Ops Manager before your "bad hair day" was finished.


2) Never found a problem with starting-up in windy conditions at all. If the a/c was parked correctly then I used the wind to lift the blades over the tailboom. Whether the M/R turned clockwise or counter-clockwise was/is the factor that also determined which side I had/have the wind coming from before start-up.

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  • 1 year later...
Starting up with the rotors stopped......now there is a novel idea. I've been doing that exact procedure for over 35 years and it works every time, at least on the Bell 47, Bell 206, Bell 212, Bell 412, MD500, R22, A109S, EC130B4 & AW139.


I'm not too sure about other helicopters but I believe you can start them with the rotors stopped also.




Me thinks Zapper68 has no experience on the AW139...... if he had he would know that it is not possible to start the AW139 with the rotor brake engaged. Remember your ground school.... on the Aw139 the rotor brake caliper assembly is mounted on an acutator arm that lowers the calipers away from the disc as soon as either engine mode switch is moved out of the "Off" position. Ergo no rotor brake starts on the AW139.

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Methinks, gentlemen and any ladies present, that Mr Zapper68 is pulling your legs hence the "ZAP ZAP" - on all helicopter types the blades are stopped before the starter button is pushed - he makes no reference to keeping the blades stopped with either one or two engines running.


Hey Red Dawg - long time no smoke signal - what news - how is the fishing????

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Some of the responses have been very funny but assuming that the original questioner really didn't know why blades have to be free to turn on startup the answer is that the only machines that have to be started with the rotor system disconnected from the engine are the earlier Aerospacial machines like the Lama and Allouette 2 and 3 that have a solid connection between the compressor and the power turbine and the starter is incapeable of pushing the rotors from the dead stopped condition. The separation of compressor and power turbine allows the engine to build up power before the blades start turning. I myself have had 212 and 412 blades held for a few seconds during a start in extremely strong winds especially if the wind is from an inconvenient dirrection to get a much quicker and safer speedup of the blades.

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