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View Full Version : Why will the P47 NOT throttle down to idle RPM??



XyZspineZyX
09-09-2003, 01:41 PM
I can't get the P47 to it's RPM's idle . It stays at around 2500 RPM or above..but when i throttle down...it will NOT go to low RPMs to idle. Anybody else getting this? I'm using version 1.11

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<img src=http://68.67.55.154:109/jerry/109popout2.jpg>

XyZspineZyX
09-09-2003, 01:41 PM
I can't get the P47 to it's RPM's idle . It stays at around 2500 RPM or above..but when i throttle down...it will NOT go to low RPMs to idle. Anybody else getting this? I'm using version 1.11

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<img src=http://68.67.55.154:109/jerry/109popout2.jpg>

XyZspineZyX
09-09-2003, 01:57 PM
Use prop pitch to lower RPM when this happens.

XyZspineZyX
09-09-2003, 02:05 PM
I imagine it has to do with the constant speed prop. As long as you have prop pitch set to 100%, the governor controlling engine rpm will adjust the pitch to maintain maximum revs. ie constant speed.

As the previous poster said, lower your prop pitch setting so the governor will allow engine rpm's to fall.

XyZspineZyX
09-09-2003, 02:15 PM
Are you in the air or on the ground? In the air, the windmilling will very effectively prevent it from ever going to idle RPM (unless you're at the top of a hammerhead or some such manouvre.)
_
/Bjorn.

XyZspineZyX
09-09-2003, 03:11 PM
This is a bug that should be fixed on all constant speed props, has been a problem since original FB. Reducing throttle results in no loss of MAP (drops intially then return to high values) This it seems is only an indication problem not a FM problem. You will actually slow down at a decreased rate if you decrease prop pitch, which is correct. Don't worry I am sure Oleg will fix this at a later date, as it is just an indication problem.

Stick with it!!

Message Edited on 09/09/0302:12PM by DGC767

XyZspineZyX
09-09-2003, 03:32 PM
DGC767 wrote:
- This is a bug that should be fixed on all constant
- speed props, has been a problem since original FB.
- Reducing throttle results in no loss of MAP (drops
- intially then return to high values)

It's not a bug. Think about what the term "Constant speed" means. It means that your propellor is spinning at a constant speed regardless of your throttle setting. And the speed of your prop is determined by the setting on your prop pitch control.

You cannot, therefore, leave the constant speed prop setting to 100% and think that your RPM's will drop when you throttle back. The governor will adjust the prop pitch so that the rpm's remain "constant", the whole idea behind constant speed props.

You have to think of your prop pitch setting as the control that adjusts your RPM, not your throttle. Try this, adjust your throttle to 100% and your prop pitch to 100%, See your RPM's? Now drop your prop pitch to 50%. Your rpm's will drop.

I hope I've made this clear.

XyZspineZyX
09-09-2003, 04:11 PM
He's talking about a different bug.

The MAP, or Manifold Air Pressure, is not directly related to the engine RPM. When you reduce Throttle on an engine with a constant speed propeller, the RPM should stay constant until the blades hit the pitch stops, but the manifold pressure should decrease.

In fact, all the throttle actually does is cut airflow to the engine, or decrease the manifold pressure, so if you reduce throttle, and there is no coresponding decrease in manifold pressure, that should be indicative of a fault in the throttle system. Typically it means the throttle is broken open and the engine is running wild, so you'll have to reduce power with the mixture instead.

As it currently stands, the Prop RMP and the Engine Manifold Air Pressure seem to be linked. That's not correct.

For aditional information see here:
http://www.avweb.com/news/columns/182081-1.html
http://www.avweb.com/news/columns/182082-1.html
http://www.avweb.com/news/columns/182084-1.html
http://www.avweb.com/news/columns/182085-1.html

And for the intracacies of turbos:
http://www.avweb.com/news/columns/182102-1.html
http://www.avweb.com/news/columns/182103-1.html
http://www.avweb.com/news/columns/182104-1.html
http://www.avweb.com/news/columns/182105-1.html
http://www.avweb.com/news/columns/182106-1.html
http://www.avweb.com/news/columns/182107-1.html

Harry Voyager

http://groups.msn.com/_Secure/0YQDLAswcqmIpvWP9dLzZVayPXOmo6IJ16aURujNfs4dDETH84 Q6eIkCbWQemjqF6O8ZfvzlsvUUauJyy9GYnKM6!o3fu!kBnWVh BgMt3q2T3BUQ8yjBBqECLxFaqXVV5U2kWiSIlq1s6VoaVvRqBy Q/Avatar%202%20500x500%20[final).jpg?dc=4675409848259594077

Message Edited on 09/09/0310:14AM by HarryVoyager

XyZspineZyX
09-09-2003, 04:44 PM
Would it really be possible for an engine to maintain combat RPM through prop pitch with the throttle at idle?

--AKD

http://www.flyingpug.com/pugline2.jpg

XyZspineZyX
09-09-2003, 04:58 PM
HarryVoyager wrote:
- He's talking about a different bug.


My bad. It's the title of the thread that I was focused on: the idea that you adjust RPM thru throttle on constant speed props. The terminology for both LW and VVS planes is the same, as well as the 0-100% settings, but they opperate differently and this leads to confusion.

But the MAP is bugged if it's working as you describe. Thanks for clarifying.



Message Edited on 09/09/0312:01PM by Chadburn

XyZspineZyX
09-09-2003, 05:01 PM
Harry and DGC767 are right ...

Swing and Chad are not ...

sorry.


Falcon

http://www.endlager.net/fis/pix/banners/fis_euro_us_02.gif

oops ... and Chad corrected while I was typing.


Message Edited on 09/09/0310:02PM by Falcon_41

XyZspineZyX
09-09-2003, 10:11 PM
I use full mixture to slow down now since the new patches. No big deal /i/smilies/16x16_smiley-happy.gif P-47 has improved so much I hate to complain about it in fear that it will be messed up again if they was to tamper with it.
47|FC

XyZspineZyX
09-09-2003, 10:26 PM
Thanks Harry for getting at my true meaning. I was just about to unleash a spray of the highest order /i/smilies/16x16_smiley-wink.gif until I was calmed by your post. Cheers /i/smilies/16x16_smiley-happy.gif



Message Edited on 09/09/0309:27PM by DGC767

XyZspineZyX
09-10-2003, 06:55 AM
Falcon_41 wrote:
- Harry and DGC767 are right ...
-
- Swing and Chad are not ...
-

Not that it really matters any, but I'm curious in what way you think I'm wrong. Note that I don't meant that the prop won't slow down, it certainly will do that, just that it won't reach idle RPM (unless, that is, the governor allows the prop pitch to go to full feathering, but I boldly made the assumption that it won't do that.)
_
/Bjorn.

XyZspineZyX
09-10-2003, 07:33 AM
VMF-214_HaVoK wrote:
- P-47 has improved so much I
- hate to complain about it in fear that it will be
- messed up again if they was to tamper with it.
- 47|FC

Improved? How? A better roll rate (somewhat) on 2 out of 3 models? An engine that is still killed at the slightest hit? Pilot kills out the wazoo?

Let them try to get away with this BS with the P-51.

Thanks for letting me rant,/i/smilies/16x16_smiley-sad.gif
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-
-
-
-



http://members.cox.net/miataman1/WAR-08.jpg

XyZspineZyX
09-10-2003, 02:33 PM
Swing,

You answered an invalid question as if it were valid, therefore your answer was invalid.

Harry corrected the question and put the IL2FB bug into context with real life.

I, wanting to say much the same thing, but being too late, attempted to capture as much fame as I could by riding Harry's coat tails.

http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif


Falcon

http://www.endlager.net/fis/pix/banners/fis_euro_us_02.gif

XyZspineZyX
09-10-2003, 08:29 PM
Bug , what do you mean.. have you ever flowen a aircraft with a prop like this..? I have .

And when you pull down on the power the prop rpm will drop just a little.
If you are in a decent your prop rpm will climb even though your engine is in idle.

You have to change the prop pitch to get the prop to slow down or it will wind mill for a very long time..

RichardI
09-10-2003, 11:09 PM
chris455 wrote:
Pilot kills out the wazoo?

You hit the proverbial nail on the head there, chris. One of the major reasons the Jug was so survivable was because the pilot was still flying! I have sveral technical manuals on the P-47 showing the armor from a lot of different angles. If you could actually hit a P-47 pilot it was likely more luck than skill. In the directly astern position, you can't even see the pilot for the armor. The number and frequency of pilot kills in FB are just plain BS. Makes me wonder if all the planes are using the same model for PK's.

Rich

<Center>http://www.ghosts.com/images/postimages/THUNDERBOLT.jpg <Center>I've got 140 109's cornered over Berlin!