Question about manual vs automatic prop

[grafspee]

I noticed that in Automatic mode max prop pitch is something like 48, but when i switch to manual i can go as far as +80.

This limit 48 makes engine over speed in dives, why is that, for me looks like major problem for P-47

Why automatic mode can advance pitch further?

Edited November 3, 2021 by grafspee

[GUMAR]

On 11/3/2021 at 7:21 PM, grafspee said:

I noticed that in Automatic mode max prop pitch is something like 48, but when i switch to manual i can go as far as +80.

This limit 48 makes engine over speed in dives, why is that, for me looks like major problem for P-47

Why automatic mode can advance pitch further?

 

Made some research and found this.

Max and min pitch settings were written on the blades.

Edited November 19, 2021 by GUMAR

[saburo_cz]

It seems that propeller pich above 48,3° is not correct and less than 18,3° .

Does not matter if AUTO or MANUAL.

[grafspee]

Thanks, it seems that this is a bug then

[Cool-Hand]

From page 36 of the DCS P47 manual pdf....

 

Propeller
The P-47D-30 engine rotates a 4-bladed Curtiss Electrics constant air speed propeller. Propeller pitch
is changed electrically. Its diameter is 12 feet and 2 inches, blade pitch range - 33° (from 23° in low
and up to 56° while in high pitch mode).

[grafspee]

1 minute ago, Cool-Hand said:

From page 36 of the DCS P47 manual pdf....

 

Propeller
The P-47D-30 engine rotates a 4-bladed Curtiss Electrics constant air speed propeller. Propeller pitch
is changed electrically. Its diameter is 12 feet and 2 inches, blade pitch range - 33° (from 23° in low
and up to 56° while in high pitch mode).

Knowing ED, different prop could be modeled then this mentioned in DCS manual.

Example whole section about engine in P-51 manual is for V-1650-3 but -7 was modeled

[Frederf]

Those are .5 not .3. The >80 degree setting is the feather position which is beyond the normal operating range. Not all of them have a feather position. Feather is more typical of multi-engine airplanes.

Manual specifies pitch range of 23.0 to 56.0 degrees with no feather position. Texture files show:

• DWG. NO. 836-2C2-18R1
• SER. NO. 257140
• ANGLE LOW 20.2
• ANGLE HIGH 55.2
• AT 42 IN. STA.

No idea what an "R1" is but manual and texture disagree a bit on the angles. High angle is coarser which causes lower RPM. Low angle is fine which is associated with higher RPM. Setting pitch to very high angles (80+) is for feather which generally stops the propeller and minimizes drag (both turning and form).

Decipher propeller model designation:

• 836 - Drawing number 836
• 2 - Interchangeability number 2
• C - Curtiss
• 2 - Blade root size 2
• 18 - diameter 18" reduction

[Cool-Hand]

 

 

I did find this List_of_Propellers_and_Governors_for_Service_Aircraft_1945_wwii and I see no feathering props on any P-47 models

[grafspee]

I as well have hard time believing  that single engine fighter have feathering prop, no much benefits from this anyway. 

Edited November 19, 2021 by grafspee

[GUMAR]

16 hours ago, saburo_cz said:

It seems that propeller pich above 48,3° is not correct and less than 18,3° .

Does not matter if AUTO or MANUAL.

Spoiler

 

There were many variants of blades, wich were interchangable

15 hours ago, Cool-Hand said:

From page 36 of the DCS P47 manual pdf....

 

Propeller
The P-47D-30 engine rotates a 4-bladed Curtiss Electrics constant air speed propeller. Propeller pitch
is changed electrically. Its diameter is 12 feet and 2 inches, blade pitch range - 33° (from 23° in low
and up to 56° while in high pitch mode).

We have 13 inch blades.

We need manual for CE prop assy. 

I posted a link, and there are some C-542 hubs with feathering angle.

 

Edited November 20, 2021 by GUMAR

[saburo_cz]

1 hour ago, GUMAR said:

There were many variants of blades, wich were interchangable

Do we have interchangeable blades in DCS W?

 

Isn`t this the reason why propeller`s hubs have adjustable blade`s pitch angle range limiters? Different blades, engines ...

[GUMAR]

On 11/20/2021 at 6:15 PM, saburo_cz said:

Do we have interchangeable blades in DCS W?

 

Isn`t this the reason why propeller`s hubs have adjustable blade`s pitch angle range limiters? Different blades, engines ...

Thats right. But what hub do we have modelled in DCS? 

[saburo_cz]

Shouldn`t be use Curtiss Electric C542S?

When you read notes in "List of Propellers and Governors ... " about the interchangeable blades for the P-47 there is sentence:

"Such procedure (means blade change) also requires a change in blade angles".

 

IMHO, difference between written blade angles on the picture i posted and on the list of propeller is probably because different place where it was measured.

Standard was Station 42, but in the list is written Station 54 ... 

 

So, 80 degrees (PRP value on INFO BAR) what is possible for the P47 in DCS seems not to be correct. I have no idea where is this value measured in DCS, but if i look on propeller with maximal angle i rather see 80° than 53,5° (or 48,5° ).

[grafspee]

@saburo_cz and this 80 prop pitch is only achievable by manual mode, when governor is in AUTO max pitch is 48, and this makes engine over rev quite often in high speed dives, no matter what i do when engine hits 2900rpm it loses main bearing.

[Frederf]

I don't believe the real airplane's propeller goes to 80 degrees in any case because no P-47 has a feathering propeller.

[saburo_cz]

Blades angles are determined by "limit switches" .

It does not matter if commands go from manual or auto, limits are always the same!

Feather limit switch is clear, it is written on the blade, value is the same like for maximal angle (high pitch) - 48,5° in our case.