R44 relight

CharlieA · September 21, 2007

just doing a conversion so excuse my ignorance...

If the starter motor cut-out is connected to the rotor brake and clutch switch why then does the relight in flight emergency not need to disengage clutch?

thanks in advance?

delorean · September 22, 2007

The clutch lock-out disengages when you're above 70% RRPM on the "key start" R22/R44. I don't know how the newer ones are with the button on the collective and extra one on the cyclic.

PA Pilot · September 23, 2007

From the R44 Raven II POH:

"Starter buttons are active when master switch is on, even if ignition switch is off."

CharlieA · September 25, 2007

thanks delorean

Not much mention in the fm about the clutch lock-out????

It is the older one i'm in.

cheers

delorean · September 25, 2007

Do you at least have the clutch lockout overide system? It should have been on anything that left the factory--new or overhaul--after the very late 90s. If you do, you'll have a jumper plug mounted above the test switch panel under the right cowling. Then you'll have two plastic jumper plugs (that are usually on the key ring or stored under the seat).

In the clutch system, you have two blue-green switches mounted side by side on the actuator arm (these are the ones NOT visable on a preflight.) When the clutch reaches its proper tension, the fans springs pop out and push the button on these switches. The first one to close will stop the motor--and it also locks out the starter (below 70% RRPM).

When you disengage the clutch, the motor is over-ridden and disengaged until the limit bolt head hits the down-limit switch (mounted on the right side above the fan scroll). If one [or both] of the fan spring switchs have stuck closed, shorted, etc, you will not be able to re-engage the clutch or start the engine (because it thinks the clutch it already engaged.)

If you have that override system, you try the each jumper plug. One jumps the right-side fan spring switch, the other, the left side. It will bypass the broken switch, allow the engine to be started, and the clutch engaged until a repair can be made (like at least 6 hrs to replace one of those little guys!!)

BTW, on the left [copilot's] side, the visable swtich on that side with the cable pigtail is an up limit switch to shut the motor off in the event both fan spring switches failed. This would keep the motor from snapping the belts or damaging the drivetrain.

Pretty awesome system. As long as the belts are kept adjusted and free of debris, there's not much to worry about. Usually, one of those fan spring switches will fail over the life of the helicopter, but with the override, you don't get stranded now. Alternator belts go out much more often than that, so I'd replace those switches when the helicopter was midlife during an alternator belt swap.