direct cranking vs inertia starter

[DELEQ]

Hey Guys,
we are nearing completion on our T6-G Project. During one of the System Tests the question arose whether to wire the starter as direct cranking or as inertia starter.
I know that the T-6 started out with the inertia type and that the wiring on the T-6G was later modified to be used as direct cranking.

Any risks or benefits on both type of configuration?

Thanks

Stefan

[Scott 'Gunny' Perdue]

I like the inertia starter quite a bit. That being said, when it came time to OH the engine on the T-6 I couldn't find anyone to OH the inertia starter as such... so it is direct now and works fine.

gunny

[DELEQ]

Thanks Gunny,
are there any Problems with the clutch engaging the engine at a higher Speed when it comes to Service life?

[C.6-60]

Hello DELEQ,
My quick 2 cents worth.

Direct drive starters are lighter meaning less weight needed in the tail for weight and balance CG and higher useful load.

If, and I hope it never happens, you ever get an induction fire from say a flooded carb. You need to keep cranking the engine over to suck up all the flames !
You do not want to wait for an inertia starter to spool up again to keep the engine cranking. Your engine accessory section will be up in flames by that time.

You need the ability to keep cranking that engine over until all the flames have disappeared or the engine has started.

With proper priming and the proper starting procedure this should never happen. But as they say, never say never!

Vincent

[DELEQ]

Hi Vincent,
the induction fire is definitly a good Point. It seems that our starter works as both types, it´s just a matter how you wire the starter Switch. You just have to leave away the engage wire, and it just spools up the starter.

Stefan

[Scott 'Gunny' Perdue]

Thanks Gunny,
are there any Problems with the clutch engaging the engine at a higher Speed when it comes to Service life?

I don't think so. The duty cycle of these starters was orders of magnitude greater in WWII than what we put them through today.

gunny

[bdk]

I set the 3-position switch up on my Stearman starter to energize the flywheel in the first detent and then the third to engage. The middle position was off and the other positions were springloaded to the center. The engagement detent was also wired to continue powering the flywheel electrically while cranking. That method extended the length of time that the engine would crank over if it hadn't already started.

Seemed to work well.

[DELEQ]

That´s exactly how we have wired it now. In the T-6G Manual is a wiring Diagramm that shows to wire both Position the same, for direct cranking only. But i guess we leave it like it is, to give us at least the Option to use the inertia starting.

[bdk]

The wind up of the inertia starter gives spectators some anticipation at least.