Cold Start: Engine Catchers w/ Ignition Off.

[Bowie]

Won't run, but it catches.

And it shouldn't, with no spark.

Unless it is dieseling.

 

Please advise.

@NineLine

 

Bowie

[grafspee]

In P51 starter button also incorporate a booster coil button which via batery energize one magneto left or right can't remember so engine has sparks even when magnetos switch is off.

[Bowie]

On 12/11/2024 at 9:21 PM, grafspee said:

In P51 starter button also incorporate a booster coil button which via batery energize one magneto left or right can't remember so engine has sparks even when magnetos switch is off.

 

On that note - did some research and hit an old DCS thread:

Quote

You need to do your research, guys.
 While the slow engine model in DCS is far from perfect, the P-51 does have a booster coil wired to the starter switch that will provide ignition even when the mags are off.
 If you want to give it 6 blades, don't prime prior to engaging the starter.

Quote

I always start turning the engine with magnetos off (and without having pre-primed the intake manifold),
 and even in the best of weather, I never get cylinders firing before I start to prime and switch magnetos to "Both" at the same time, namely after 6 blades.

Quote

 He explains why he does it.

It's the opposite of what the hand cranking of the rotaries is intended to achieve.

He's not clearing oil to avoid a catastrophic failure, he's adding oil to prevent wear at start-up.

If the engine's been sitting for a while all the oil will drain down, and there's nothing sitting in the oil-ways so starting the engine from this state
 would meant that if it caught straight away, the first few revolutions would be running with no oil pressure at the con-rod, cylinder & cam-shaft.

If the engine were started like that the pressures generated by the running engines would be carried by the un-lubricated (presumably soft white metal) bearings,
 and the cam followers would be running metal to metal.

If he cranks the engine without firing it (or in this case starts the electric oil pump) he turns the oil pump & fills the oil-ways and gets the inside of the cylinder oiled
 so everything is lubricated before the engine faces combustion pressures.

So:

- Mixture-Idle Cutoff/Fuel Booster-On/Ignition-Off/Primer-Off, them

- Cover-UP/hold Starter-On, Crank 6-propeller blades to oil - then

- add Ignition-Both/hold Primer-On, and then Mixture-Run when it catches, then

- release Starter/Primer Off, Cover-Down.

Would be a nice addition to the DCS P-51D Manual and Start-Up training mission.

@NineLine

 

Bowie

 

Edited December 13, 2024 by Bowie

[Art-J]

DCS manual pretty much copied real wartime manual procedure word by word so there's nothing to add or adjust really.

Restored warbirds are often started (and operated in general) little different, 'cause durability, reliability and overhaul costs are prevailing considerations nowadays (not talking about unlimited class Reno racers, which are a peculiar exception). Not to mention modern modifications (e.g. pre-oiling systems) which were not there on these engines during wartime.

Following alternative startup procedures is a bit pointless anyway, as DCS engine modelling is not THAT deep and some aspects (like engine "catching" on startup or backfires on shutdown) are scripted and always happen the same way. I remember Yo-Yo explaining that coding in extra intricate details (which would make engine startups more random and finnicky) is useless in combat sim, where most players would want to skip it anyway after short honeymoon period of novelty fasctination. I understand where he's coming from. That kind of detail (coupled with persisting systems state simulation) will always be more apprieciated by civilian flight sims crowd.

Nothing wrong about doing it for immersion, though, so if you want to crank six blades etc., go for it.

[grafspee]

 War time P-51 were cranked by hand  prior start up by ground crew during preparation aircraft for mission so pilot could jump in cockpit flip starter and that's it.

Modern time P-51 are modified so ground crew don't have to crank engine by hand it is just convenient for modern users. Take note that planes like P-47 or any other vintage plane which is equipped  with inertia starter is still today cranked by hand before start up.

Cranking engine before start up is safety procedure to not encounter hydro-locked piston during engine start up if not checked bended connecting rod is guarantied.

DCS P-51 is war time version so there is no "counting 6 blades" during start up procedure.

[Bowie]

1 hour ago, grafspee said:

... DCS P-51 is war time version so there is no "counting 6 blades" during start up procedure.

DCS P-51D-25-NA... models the "six propeller blade oiling", in the AI startup sequence.

Nice to have the procedure now.

 

Bowie

Edited December 13, 2024 by Bowie

[grafspee]

13 hours ago, Bowie said:

DCS P-51D-25-NA... models the "six propeller blade oiling", in the AI startup sequence.

Nice to have the procedure now.

 

Bowie

So this is inaccurate then. And by turning 6 blades you will oil nothing. This is another misconception, turning engine so slow oil pump has no chance to pick up any oil or pump any decent oil volume to do any oiling. In modern P-51 when plane was set back for long period, they use electric oil pump to pre-oil engine before start up, this is only way to pre-oil engine. Turning 6 blades is just check before start up that engine can freely rotate.

In war time manuals that is said that count blade check is done by hand rotating engine by ground crew.

Operating starter longer then 15s continuously was forbidden so no cranking engine by starter for other reason then engine start up.

Another thing is oil pressure behavior in DCS, in real plane it may take even 20s after start to build up oil pressure  at the oil pressure sensor. In DCS we have oil pressure even when we cranking engine via starter which is not true at all.

In DCS we have instant 200 psi oil pressure

 

Edited December 14, 2024 by grafspee

[Bowie]

On 12/14/2024 at 12:53 AM, grafspee said:

So this is inaccurate then. And by turning 6 blades you will oil nothing. This is another misconception, turning engine so slow oil pump has no chance to pick up any oil or pump any decent oil volume to do any oiling. In modern P-51 when plane was set back for long period, they use electric oil pump to pre-oil engine before start up, this is only way to pre-oil engine. Turning 6 blades is just check before start up that engine can freely rotate.

In war time manuals that is said that count blade check is done by hand rotating engine by ground crew.

Operating starter longer then 15s continuously was forbidden so no cranking engine by starter for other reason then engine start up.

Another thing is oil pressure behavior in DCS, in real plane it may take even 20s after start to build up oil pressure  at the oil pressure sensor. In DCS we have oil pressure even when we cranking engine via starter which is not true at all.

In DCS we have instant 200 psi oil pressure

 

 

What are the key commands or radio calls to initiate hand propping by the ground crew, like the start cart for the jets?

... so that one does not have to oil the engine six propeller blades with the starter.

 

Bowie

[grafspee]

11 hours ago, Bowie said:

 

What are the key commands or radio calls to initiate hand propping by the ground crew, like the start cart for the jets?

... so that one does not have to oil the engine six propeller blades with the starter.

 

Bowie

There is non right now but at this state of DCS hand turning prop or doing six blade check is pointless. You will never have engine locked in DCS. 

But that would be indeed nice thing to be able to order ground crew to turn prop before start up

Edited December 16, 2024 by grafspee

[Skewgear]

On 12/14/2024 at 8:53 AM, grafspee said:

So this is inaccurate then. And by turning 6 blades you will oil nothing. This is another misconception, turning engine so slow oil pump has no chance to pick up any oil or pump any decent oil volume to do any oiling. In modern P-51 when plane was set back for long period, they use electric oil pump to pre-oil engine before start up, this is only way to pre-oil engine. Turning 6 blades is just check before start up that engine can freely rotate.

In war time manuals that is said that count blade check is done by hand rotating engine by ground crew.

Operating starter longer then 15s continuously was forbidden so no cranking engine by starter for other reason then engine start up.

Another thing is oil pressure behavior in DCS, in real plane it may take even 20s after start to build up oil pressure  at the oil pressure sensor. In DCS we have oil pressure even when we cranking engine via starter which is not true at all.

In DCS we have instant 200 psi oil pressure

 

Where on earth do you get all this nonsense? Nearly every single thing you have posted above, except for oil pressures, is wrong. Show your sources, please.

[grafspee]

6 hours ago, Skewgear said:

Where on earth do you get all this nonsense? Nearly every single thing you have posted above, except for oil pressures, is wrong. Show your sources, please.

 

I have couple sources but this one should be enough. If not I can't help you. Pre-oil engine.

Now it is your time shine, show me your sources.

 

Edited December 16, 2024 by grafspee

[Skewgear]

This is a video of Kermit Weeks sitting in his P-51C's cockpit while a noisy pre-oiling pump runs. That's a relatively common mod to Merlin-engined warbirds that are flown infrequently but is neither compulsory nor a factory fitting. It does not address anything you've claimed about how the Merlin V-1650 works.

Show the sources for these claims of yours, please:

Quote

So this is inaccurate then. And by turning 6 blades you will oil nothing. This is another misconception, turning engine so slow oil pump has no chance to pick up any oil or pump any decent oil volume to do any oiling. In modern P-51 when plane was set back for long period, they use electric oil pump to pre-oil engine before start up, this is only way to pre-oil engine. Turning 6 blades is just check before start up that engine can freely rotate.

In war time manuals that is said that count blade check is done by hand rotating engine by ground crew.

Operating starter longer then 15s continuously was forbidden so no cranking engine by starter for other reason then engine start up.

 

[grafspee]

2 hours ago, Skewgear said:

This is a video of Kermit Weeks sitting in his P-51C's cockpit while a noisy pre-oiling pump runs. That's a relatively common mod to Merlin-engined warbirds that are flown infrequently but is neither compulsory nor a factory fitting. It does not address anything you've claimed about how the Merlin V-1650 works.

Show the sources for these claims of yours, please:

 

Pre-oiling fresh engine include external oil pump, that did not change since war time till today.

If engine is used frequently, engine stays pre-oiled if used rarely you need to pre oil it. Doing 6 blade, engine pre oil status remain exactly the same as before 6 blade count.

Ground crew doing blade check.

15s starter limit.

Hand turning engine is just safety and reduce risk of serious engine damage if something will lock piston from movement.

I already responded twice, but you still refused to present your proof or sources, im still waiting.

It is quite odd that you did not read P-51 manual and P-51 maintenance manual. 

If i go thought maintenance manual when refilling oil or coolant they just started engine for 1-2 min if they do timing adjustment they hand turn engine, i doubt that they used starter for anything else then starting engine.