[CORRECT AS IS]Engine starts with mags off

[Badders46]

I was on the SoW server this evening after it was rolled back to release and I noticed but accident that the engine will start with the mags set to off. This was purely by accident as l had engaged the starter before switching the mags to both..

In addition, in the latest open beta (on another server) and the release version I flew in this evening, thw R/H mag always drops considerably and there is nothing that clears it.

 

Once the engine is running and the mags are switched to on, switching them off, even if flight doesnt kill the engine.

 

Apologies if this has been reported already!

 

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[Badders46]

Updated to include Track file as requested by BigNewy

P-47 Mag Track.trk

[BIGNEWY]

Reported to the team for investigation

 

thank you

[BIGNEWY]

I have spoken to the dev, this is correct as is, the starter button also affects one of the magnetos

 

thanks

[Badders46]

I have spoken to the dev, this is correct as is, the starter button also affects one of the magnetos

 

thanks

Awesome - cheers for checking it for me!

 

Sent from my SM-G950F using Tapatalk

 

 

[BIGNEWY]

no problem :)

[Andrew8604]

This is good, but could you explain just a bit more.  And I am not disputing this, just want more details to fully understand it. 

With mags switch off, flipping the starter switch from energize to engage, both engages the starter and closes the circuit on one of the magnetos, overriding the mags switch?  What happens when the start switch is released to off?  Does that one magneto remain on?  If so, how is it subsequently cut off again?  By turn mags switch on and then off?

Or is this all explained in the P-47D manual?

There must be a reason for Republic and/or Pratt & Whitney to have made it this way.  Is it possibly to prevent a faulty or damaged mags switch from causing engine failure?  Is the cockpit mags switch not directly in the magneto ignition system circuit, such as only activates relays?

Is there a procedure for the P-47D where you crank the engine through a couple turns of the propeller before starting?  If so, that would have to be done before priming and with fuel at cutoff, right?  Or maybe there is no such procedure.

Edited December 12, 2020 by Andrew8604

[grafspee]

On 12/12/2020 at 11:00 PM, Andrew8604 said:

This is good, but could you explain just a bit more.  And I am not disputing this, just want more details to fully understand it. 

With mags switch off, flipping the starter switch from energize to engage, both engages the starter and closes the circuit on one of the magnetos, overriding the mags switch?  What happens when the start switch is released to off?  Does that one magneto remain on?  If so, how is it subsequently cut off again?  By turn mags switch on and then off?

Or is this all explained in the P-47D manual?

There must be a reason for Republic and/or Pratt & Whitney to have made it this way.  Is it possibly to prevent a faulty or damaged mags switch from causing engine failure?  Is the cockpit mags switch not directly in the magneto ignition system circuit, such as only activates relays?

Is there a procedure for the P-47D where you crank the engine through a couple turns of the propeller before starting?  If so, that would have to be done before priming and with fuel at cutoff, right?  Or maybe there is no such procedure.

 

1. once you release starter switch engine will die when both magnetos are off. Whole thing is that magnetos cant provide strong sparks for ignition at low rpm, way around is to use battery energized coil which will provide strong spark.

This is how magneto ignition looks like, magneto switch is shutting off only power generator for ignition, both distributro and spark generator are still fully operational then you can tap in with batter energized coil which will provide power to make spark.

2. There is not mention in  manual to crank engine dry before start up by using internal starter, is it spitfire,p-51 or p-47, ground crew job is to crank engine by hand to check if it is not locked before start up.

Edited December 26, 2020 by grafspee

[Shibbyland]

Did the OP say the engine remains running in flight once Mags are selected off? Is this both mags selected to off as that doesn't make sense to me. The magnetos are there to provide electrical power to the ignition system independent of the battery, to my knowledge, they must be operating for the engine to run.

 

In addition to grafspee's post above about magnetos providing spark at low RPM. I don't know about the P-47s ignition system, but many piston engine aircraft have an impulse coupling on one of the magnetos, it is independent of the battery. This provides a larger and delayed spark during engine start to overcome the issue of low RPM. 

I am curious to know how the engine is started without the magnetos selected to both. As I understand, a piston aircraft can be started without the battery (such as through prop swinging) but it can't be started without the magnetos.

Edited December 27, 2020 by Shibbyland

[grafspee]

4 hours ago, Shibbyland said:

I am curious to know how the engine is started without the magnetos selected to both. As I understand, a piston aircraft can be started without the battery (such as through prop swinging) but it can't be started without the magnetos.

 

It depends on ignition setup,  but in case of those warbirds when starter button is hit you have battery ignition, once you lift starter magnetos takes over.

Spitfire has separate this function so it has starter button and booster coil button.

If engine keeps running after release of starter button with mags off then it is a bug.

Magneto is just independent electric generator, if plane has ignition coil, it will start up with magnetos off, but once you cut off starter coil booster engine will die.

Everything depends on how circuit is arranged, if magnetos switch is also cuting off booster coil engine wont fire in this case if not engine will fire up.

And i tested it, engine will die once you release starter button, additional to this engine runs very weak w/o magnetos on, at 30inch you can barely go above 1000rpm once you hit magnetos power will come back.

 

 

Edited December 27, 2020 by grafspee

[Shibbyland]

I never knew that about the Spitfire (or other warbirds for that matter). I love the level of detail that goes into the aircraft in DCS. I have the P-47 for another WW2 sim but it's really badly done. I'd like to purchase P-47 for DCS but I don't play multiplayer and there's pretty much no missions and absolutely no campaign.

 

I got a bit slow on finals earlier, started to sink, gave a big burst of power but it was too late and resulted in a 6g landing. Somehow the landing gear survived but I broke the engines main bearing. New damage model is awesome.