Manifold Pressure Regulator

[saburo_cz]

Am just asking.

pressure regulator?

automatic pressure regulator?

 

Is anywhere used word "automatic" in conection with boost control in documentation for the P-47? (like in manual for the P-51, for example)

[grafspee]

@Wizard_03

You can not have automatic boost control while having throttle and boost lever as separate levers.

https://www.enginehistory.org/Turbochargers/TSCtrlSys/TSCtrlSys1.shtml

In P-47D only automatic regulator was turbosupercharger regulator but this regulator used only exhausts back pressure as reference so pilot had to constantly adjust boost lever to maintain boost this already exclude regulator like in P-51 or Spitfire where you can set power and automatic regulator will take care but not in P-47

Proper automatic boost regulator was introduced in P-47N-25 and there you have single throttle lever and automatic boost regulator which takes care of turbosupercharger and supercharger boost.

So once again no P-51 like boost regulator in P-47D

You have manually controlled throttle valve at supercharger inlet and automatic supercharger regulator which maintains set back pressure.

And none of those will prevent from over boost, does not matter if this over boost comes from turbosupercharger or RAM air.

Edited October 11, 2023 by grafspee

[Brigg]

14 hours ago, grafspee said:

 

@Wizard_03 So what max boost should be governed by this boost regulator ? 52" or 64" ?

This is form P-47N manual and starting with P-47N-25 automatic engine control showed up but this one only control throttle valve and turbo waste gate to operate in best efficiency but still over boost could happen if you push throttle too far.

P-38 was plane from different company as well any other so this is no near proof that P-47 had ever automatic boost control.

P-47 D manual.

This should answer your question, P-47 did not have boost control like in P-51 or spitfire, if you pushed throttle and boost too far you will over boost.

So this mean that all other sims failed to deliver proper engine model

That is why i always choose DCS.

 

 

Yeah looks like ive got mixed up with the back pressure regulator

 

Edited October 11, 2023 by Brigg

[grafspee]

32 minutes ago, Brigg said:

That is from this manual https://imgur.com/dAJRVVZ in which it states its for planes equipped with a -21 engine https://imgur.com/gzRg0DE

In this manual which https://imgur.com/XhZOaqc which will be for a -59 engine there is no mention of that note and the only caution is to unlink when ground temp is 35c or higher. it also says that the take off stop can be bypassed on take off as well https://imgur.com/DwcX7is

 

 

Even for models 25 through 35 you have take off stop which mean that 52" is achieved not at 100% throttle movement like it is in P-51.

But still it does not provide any proof of having automatic boost control like in P-51.

And as you can see in this manual power chart shows that P-47 is capable of making 52" at 34k of alt.

I can tell that you can over boost P-47 even without turbo, you just need enough ram air to do it and you can get +52" on supercharger only.

There are planes with take off stop and there are with out it why so i don't know.

And turbo regulator job is to maintain set boost level but reference is not boost pressure but exhaust back pressure and this makes regulator imperfect which require during climb to retard boost lever and from some point to maintain boost pilot has to advance boost lever. This boost regulator does not governs turbo rpm so pilot has to monitor torbo rpm.

Edited October 11, 2023 by grafspee

[Wizard_03]

The boost lever has nothing to do with the regulator, the regulator simply blows off excess manifold pressure through the wastegates above what ever setting the aircraft is configured for, 64" wet in this case. Regardless of throttle or boost lever settings.

 

Full safe power should be the absolute limit in any case, they didn't include a self destruct button at the end of the throttle travel. In any case it's up to ED, they have the bug report now and they can provide an explanation as to why their aircraft is the way it is. 

[grafspee]

9 hours ago, Wizard_03 said:

The boost lever has nothing to do with the regulator, the regulator simply blows off excess manifold pressure through the wastegates above what ever setting the aircraft is configured for, 64" wet in this case. Regardless of throttle or boost lever settings.

By typing it i can see that you have no bloody idea how this works.

Regulator does not blow excess manifold pressure though wastegates.

Turbo regulator control exhaust gases, it divert those in to turbine and blows excess and how much it divert to turbine directly depends on boost lever position in cockpit.

Turbocharger control unit only measure exhaust back pressure it does not measure boost (manifold pressure).

This mean that if manifold pressure changes due to alt change or ram air and exhaust back pressure stay the same turbo regulator will not do anything.

And i don't know that any boost regulator regulate manifold pressure by venting boost in to air. This is not how automatic boost regulator works in P-51 or Spitfire

Edited October 12, 2023 by grafspee

[SRF_Robert]

On 10/11/2023 at 12:40 PM, grafspee said:

By typing it i can see that you have no bloody idea how this works.

Regulator does not blow excess manifold pressure though wastegates.

Turbo regulator control exhaust gases, it divert those in to turbine and blows excess and how much it divert to turbine directly depends on boost lever position in cockpit.

Turbocharger control unit only measure exhaust back pressure it does not measure boost (manifold pressure).

This mean that if manifold pressure changes due to alt change or ram air and exhaust back pressure stay the same turbo regulator will not do anything.

And i don't know that any boost regulator regulate manifold pressure by venting boost in to air. This is not how automatic boost regulator works in P-51 or Spitfire

 

I second this, if you need a manual on the specific turbo I can provide that.