reported Able to start cold engine with magnetos OFF just by holding the prime switch

[Lau]

Hi, 

I am able to start a cold engine with magnetos OFF, just by holding the prime switch and with mixture OFF. Without magnetos, there should be no ingnition, technique used to lubricate a cold engine prior to start up. 

Best,

Lau

 

[Art-J]

 

[grafspee]

8 hours ago, Lau said:

Hi, 

I am able to start a cold engine with magnetos OFF, just by holding the prime switch and with mixture OFF. Without magnetos, there should be no ingnition, technique used to lubricate a cold engine prior to start up. 

Best,

Lau

 

This is big misconception, at low rpm oil pump won't pick up any oil so you are craking engine dry. Only thing which you can check that way is that engine isn't hydro locked and can freely rotate. Modern warbirds has different wiring setup so with magnetos off you can check that. War time P51 had different setup and ground crew was doing check by hand cranking engine before start up.

P51 engine uses battery powered coil booster to provide spark at low rpm because magnetos provide weak spark at starter rpm, coil booster switch is linked to starter switch so as you flip starter ignition system is energized by booster coil even when magnetos are off.

Edited June 21, 2023 by grafspee

[Lau]

Gentleman’s,

Thank you for your replies.

For me there is an effect missing in the SIM, and it is the effect of an engine that is being primed, receiving some but not enough powerful sparks from the booster coil as the magnetos are still turned OFF, the player should also be punished by using too much prime. So you might get some flames and a couple of bangs here and there, but in no way should the engine have sufficient sparks to start without the magnetos.

It is therefore a BUG that I would like ED to fix in the same way, as the one allowing players to use the starter switch continuously without damaging the starter, which should heat to the point of catching fire. I will report this last one in a separate topic.

Ignition system :

« Two engine-driven high-tension magnetos mounted on the engine, supply spark for combustion and are grounded when the ignition system is inoperative. Both magnetos have booster coil connections, but only the one on the right magneto is used. The booster coil intensifies the spark of the right magneto to aid in starting. »

Note: booster coils are an aid to the magnetos

Ignition switch :

« The ignition switch has four positions OFF, R, L, and BOTH »

Caution :

« To prevent accidental engine start, be sure ignition switch is moved to OFF after IDLE CUTOFF position of mixture control is used for stopping engine. »

Starter system:

The starter system consists of an electric direct-cranking starter, a starter switch, and a booster coil. To aid the magnetos when rpm is low during cranking, a booster coil intensifies the spark of the right magneto, which fires the intake spark of each cylinder.

Note: the booter coil aids at low rpm, but in no way it starts alone the engine and, even if it is directly wired to the starter in the wiring schematics.

Starter switch:

The starter switch has an ON position and a spring-loaded guard OFF position. Holding the switch at ON energizes both the starter and the booster coil.

Note: The starter should be better simulated as previously stated.

About being able to start the engine with mags OFF

As far as I understood, this could happen with ideal atmospheric starting conditions, an engine that is still warm and was shut down with the mixture cut-off, therefore with fuel right at the gate of the induction manifold. However you might get some insufficient sparks from the booster coil without the magnetos, some bangs and little flames here and there from residual fuel getting ignited, but the engine should not be able to start with the magnetos OFF, it’s a security clearly stated in the manual. All P51Ds being different now a days, the standard P51D as in the manual should be the reference.

Exterior inspection

“Ignition switch OFF” safety measure to prevent an engine start, this relates to the previous “caution” advisory in the event the engine was shot-down using the mixture IDLE CUTOFF, hence perhaps, the good habit of maxing throttle as the engine shots-down to starve all lines of fuel as much as possible.

@Art-J

Art-J wrote on oct 17^th 2016 that it is a script error that has been around since the release of the DCS P51D. I noticed from he’s message that he doubt that any of this will be fixed by ED, which is disappointing considering that the product is still on sale. As a customer, one can expect ED to follow the same standards they are following in all their products, meaning that they never stop improving them, being respectful for the time their customers spend trying to understand how complex machinery operates, which is the beauty of our hobby, so please do not take it away unless you are paid to do so by ED. That has nothing to do with being a loophole-searcher or nitpicker but, just expecting that the feedback provided to ED translates in to updates that fix stuff that can be fixed, hence justifying the 49.99 USD price tag set in 2023 for the product.

In other words, customers should be able to expect the P51D to behave as its real counterpart within the limits of simulation, making it worthy to go through the pain staking process of digging in to manuals and hours of testing in the sim. Here of course, I include the BUG where after a miss-fire engine or an engine that does not want to start after several attempts, can be run by holding the starter switch. Since it is spring loaded, there is a way to hold it in a continuous start position by simply flipping the cover on and off once.

If it’s a BUG or inaccurate, then it should be fixed, without it having to take seven years or more, there is certainly no need to incentivize ED for not fixing or improving stuff, they are slow enough.

Take it from a different perspective, some people don’t care, some actually flew the real thing, others worked on maintenance on the real thing. Dedicated customers only have the SIM which is limited enough, hence our expectations.

@grafspee

Sobek wrote at the same time something along what you wrote back in 2016, all agreeing on the pre-lub with six blades procedure by not priming a cold engine to prevent it from starting. If the engine has an oil sump then, there are parts getting in contact with the thick oil, hence the need to use low rpm with a cold engine to avoid any damage to these parts. The engine being inclined by the plane position on its landing gear, there is probably a filter system preventing all the oil from draining to the lower parts. I therefore think that pre-lub with six blades is not a “big misconception” as stated in your message. I can’t help it but to feel depressed when I get patronized for no special reason.

Best,

Lau

 

[grafspee]

@Lau 

Magneto has build in distributor which is powered by magneto's high-tension current generator which is grounded when magneto switch is in off position, but both distributors have additional finger for external power which is booster coil, only Bank A is energized by booster coil while starter is engaged and this alone is sufficient to start engine.

Running engine on booster coil alone in DCS has significant draw back like significant power loss.

No starter overheat and no rough engine run is definitely missing from DCS.

Same with over priming, my opinion is that whole starting script needs refurbish, definitely ! 

In modern P-51 booster coil circuit has additional switch incorporated in magnetos switch which cuts off booster coil too.

 

Edited June 21, 2023 by grafspee

[NineLine]

Priming has been "broken" for some time and already reported. I will check on the rest reported here. 

On 6/21/2023 at 12:48 PM, Lau said:

If it’s a BUG or inaccurate, then it should be fixed, without it having to take seven years or more, there is certainly no need to incentivize ED for not fixing or improving stuff, they are slow enough.

You have given a very well-thought-out and detailed report. While I understand your frustration with bugs and the time it takes to fix some, being rude about it will not get things looked at faster. Thanks. 

[NineLine]

On 6/20/2023 at 11:37 PM, Lau said:

Hi, 

I am able to start a cold engine with magnetos OFF, just by holding the prime switch and with mixture OFF. Without magnetos, there should be no ingnition, technique used to lubricate a cold engine prior to start up. 

Best,

Lau

 

Hi, why are you holding the priming button while cranking the engine? Is this a specific procedure you are following and from where? Also, I do have the engine try to fire if I do this, but it doesn't actually run. If the engine is actually running for you during this, please include a track. 

[Lau]

@NineLine

Quote ART-J

"That's been popping up every now and then for years in this section of the forum.

DCS Mustang, just like the Spit (same engines in practical term) has a booster coil in its ignition system, which powers up plugs during cranking even when mags are off (as they might not fire when cranking speed is too low, ie. very cold engine). Unlike in the Spit though, here we've got starter and booster wired to a single switch.

Granted, there is a simplification/bug in DCS, which makes it possible to even fly the Mustang continuously with mags off, just by keeping the starter switch on all the time (which would quickly kill both starter and booster in real life I'm sure), but I don't think ED will bother fixing it, since flying that way is only something dedicated loophole-searchers and nitpickers would do just for the feck of it and the switch is spring-loaded anyway (unless you assign it to otherwise in your HOTAS), plus I recall the engine develops severely limited power in such scenario."

Hi, 

At the time I tested this back in June it was possible to start and run the engine by locking the starter (just run the starter and lower the guard cover to lock in in place) and continuously priming the engine to bypass the mixture held in the cut off position as well as the magnetos in the off position for the duration of the test.  Carb on RAM & HOT air, Fuel Booster ON, fuel shut off to ON. At the time I did this test for me it was a mystery as to how an engine could start without magnetos and bypassing the Mixture Cut Off lever (civil aviation background). After my initial msg I learned from ART-J and grafspee about the booster coils not mentioned in the P51D manual I was referencing (above quote)

I tried to reproduce this in the latest MT 2.9  beta and it is not longer possible to do so.  The engine will only start after the mixture is set to RUN. So something changed in the script and fixed it in MT 2.9 latest beta.

I have not tried flying the plane without magnetos to witness the reduction in power.

The guard button should bring the starter button to the off position when covered

The starter can be run unlimited without overheating or catching fire (just reported this in a separate topic).

For that matter it seems impossible to drain the battery, ground power off. (just reported this in a separate topic).

There is no effect of over priming the engine or rough engine run

Information about booster coil could be added to the user manual

The engine starting script seems very basic as is and could be improved to better simulate the different scenarios about engine starting management; including smoke colors; sounds, vibrations and flames.

Best;

Lau

Edited November 9, 2023 by Lau

[Lau]

18 hours ago, NineLine said:

Priming has been "broken" for some time and already reported. I will check on the rest reported here. 

You have given a very well-thought-out and detailed report. While I understand your frustration with bugs and the time it takes to fix some, being rude about it will not get things looked at faster. Thanks. 

 

@NineLine

NineLine,

It is all a matter of perspective, from my point of view being frustrated to spend more time dealing and reporting bugs than actually having fun in the sim is also not very considerate by ED, not to call it rude since it is implied, everyone knows about it and this is what we have, so be it.

For me the problem lies in the business model, not an ED problem since the company is making money and I am all in favor of that, but not at the expense of your customers with a race to produce more and more unfinished modules.

I for it I’m getting every day closer to the 1000 EUR mark of maps, missions and modules, you can call me a fan of ED work or more precisely a fan of military aviation.

Granted, hopefully one day it will all come together and we will all forget about it, in the mean time, four and half months to address a bug report and God knows how long more before it is actually fixed in a future release is a long time to wait in my humble point of view. Here I am talking in general.

Yes we can fly as is and continue enjoying AI that is allowed to fly through trees to escape a dog fight, to later reappear behind you, it’s a game but certainly an unfinished business, something that ED has managed to hide very well through some fantastic video editing.

Best,

Lau

Edited November 9, 2023 by Lau

[NineLine]

I have reported flight on the starter motor, I cannot imagine this is realistic at all. Thanks!

FYI, the engine will run in flight with the starter switch on and mags off, but chances are you will bust the starter pretty fast. This is from Mr Grey in reference to the real thing.