PDA

View Full Version : Manipulating prop pitch



Mitlov47
04-24-2004, 05:30 PM
Last night I mapped the throttle on my joystick to prop pitch. I'd heard people talk about manual prop pitch but had never tried it before.

On most aircraft, it didn't seem to have a noticeable effect--I just kept it at 100% all the time.

But on the BF-109 (especially later models like the K4) the effect was drastic. I was able to achieve a much faster climb rate by switching to manual prop pitch and slowly increasing the prop pitch as I climbed and lost airspeed--I was trying to match RPMs by sound.

So here's my questions:

1) Do you use manual prop pitch, or leave it on auto? If you use manual, do you leave it on manual all the time, or only switch it to that for certain circumstances?

2) Do you use it on just the BF-109, or any other planes?

3) Are there any significant uses for it besides the climbing-more-quickly example I gave?

4) What do you do with the throttle when you're manipulating prop pitch? Leave it at 80? Leave it at 100%? Manipulate it as well?

http://www.onpoi.net/ah/pics/users/387_1082406218_spitfiresigsmall2.jpg

Mitlov47
04-24-2004, 05:30 PM
Last night I mapped the throttle on my joystick to prop pitch. I'd heard people talk about manual prop pitch but had never tried it before.

On most aircraft, it didn't seem to have a noticeable effect--I just kept it at 100% all the time.

But on the BF-109 (especially later models like the K4) the effect was drastic. I was able to achieve a much faster climb rate by switching to manual prop pitch and slowly increasing the prop pitch as I climbed and lost airspeed--I was trying to match RPMs by sound.

So here's my questions:

1) Do you use manual prop pitch, or leave it on auto? If you use manual, do you leave it on manual all the time, or only switch it to that for certain circumstances?

2) Do you use it on just the BF-109, or any other planes?

3) Are there any significant uses for it besides the climbing-more-quickly example I gave?

4) What do you do with the throttle when you're manipulating prop pitch? Leave it at 80? Leave it at 100%? Manipulate it as well?

http://www.onpoi.net/ah/pics/users/387_1082406218_spitfiresigsmall2.jpg

ZG77_Lignite
04-24-2004, 06:59 PM
Do you want the historic/realistic answer or the FB 'game-the-game'/exploit answer?

TgD Thunderbolt56
04-24-2004, 07:03 PM
http://ubbxforums.ubi.com/images/smiley/16x16_smiley-indifferent.gif



http://home.earthlink.net/~aclzkim1/sitebuildercontent/sitebuilderpictures/il2sig2.jpg

SeaFireLIV
04-24-2004, 07:14 PM
I`d like to hear the historic vs FB answer. i`ve always wondered on this. I guess it`ll be a longer answer, so I`ll go to bed (it`s 2 am now) and read it in the morning!

Mitlov47
04-24-2004, 07:51 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ZG77_Lignite:
Do you want the historic/realistic answer or the FB 'game-the-game'/exploit answer?<HR></BLOCKQUOTE>

Honestly, I'd be interested in both.

I don't play online (lousy internet connection) so nobody needs to worry about me using any FM inaccuracies unfairly against them. The only person I'd be abusing is the AI, and AI cheats more than anyone else out there.

But I'm also interested in history for history's sake, and searching Google for "prop pitch" doesn't tell me anything useful. Certainly nothing as useful as some of the knowledgable members of this forum.

http://www.onpoi.net/ah/pics/users/387_1082406218_spitfiresigsmall2.jpg

Maple_Tiger
04-24-2004, 08:29 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by EMitton:
Last night I mapped the throttle on my joystick to prop pitch. I'd heard people talk about manual prop pitch but had never tried it before.

On most aircraft, it didn't seem to have a noticeable effect--I just kept it at 100% all the time.

But on the BF-109 (especially later models like the K4) the effect was drastic. I was able to achieve a much faster climb rate by switching to manual prop pitch and slowly increasing the prop pitch as I climbed and lost airspeed--I was trying to match RPMs by sound.

So here's my questions:

1) Do you use manual prop pitch, or leave it on auto? If you use manual, do you leave it on manual all the time, or only switch it to that for certain circumstances?

2) Do you use it on just the BF-109, or any other planes?

3) Are there any significant uses for it besides the climbing-more-quickly example I gave?

4) What do you do with the throttle when you're manipulating prop pitch? Leave it at 80? Leave it at 100%? Manipulate it as well?

http://www.onpoi.net/ah/pics/users/387_1082406218_spitfiresigsmall2.jpg <HR></BLOCKQUOTE>


Alied planes do not have manual prop pitch. You can only change the RPM setting. The governor changes the prop pitch automaticaly to keep the RPM at your setting.

Capt. 361stMapleTiger.
http://img52.photobucket.com/albums/v158/Maple_Tiger/FBAA2.gif
Proud member of the FBAA and Nutty Philosohpy Club.

Tully__
04-25-2004, 12:10 AM
For some background, read Those Marvelous Props (http://www.avweb.com/news/columns/182082-1.html) by John Deakin at AvWeb.

=================================================


http://members.optusnet.com.au/tully_78th/legalsig.jpg

IL2 Forums Moderator
Forum Terms of Use (http://www.ubi.com/US/Info/TermsOfUse.htm)
Tully's X-45 profile (SST drivers) (http://members.optusnet.com.au/tully_78th/fb.zip)

Salut
Tully

kubanloewe
04-25-2004, 02:07 AM
it´s no bug it´s a feature, be sure school physics is not enough...

780km/h my record on a K4 http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif ; with no doubt that´s historicall correct as the P51 turnability and the P47 climbability !

http://home.arcor.de/kubanskiloewe/g14gutspruchsig.jpg
"Finde den Feind und schiesse ihn ab alles andere ist Unsinn"
Rittmeister Freiherr Manfred von Richthofen

JG5_Scorpius
04-25-2004, 03:40 AM
@ Maple_Tiger

Your statement about alied fighters is not correct. The P-38 and P-40 did have electric propeller pitch control systems. If you switched off the auto mode, they would become fixed pitch propellers that could be adjusted manually similar to the 109.
To make this simulation a bit more realistic, the performance increase you get on the 109 when using manual prop pitch should have the penalty of engine failure after 5 minutes. You are basically abusing a factory fresh engine every flight, instead of having to fly with it for 25 or 30 hours.

Regards, Scorpius

Extreme_One
04-25-2004, 03:52 AM
I've asked before about the historical aspect of using Auto prop pitch but had no reply.

It seems strange to me that the feature was built into the plane and the first thing that the pilot did was disable it?!?

I'd really like to know more about this...

S! Simon
'''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''
Download the USAAF & RAF campaign folders here (http://www.netwings.org/library/Forgotten_Battles/Missions/index-10.html).

Download "North and South" including the Japanese speech-pack here (http://www.netwings.org/library/Forgotten_Battles/Missions/index-12.html). *NEW*

http://server5.uploadit.org/files/simplysimon-spit_sig.jpg

ASM 1
04-25-2004, 04:45 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by kubanloewe:
it´s no bug it´s a feature, be sure school physics is not enough...

780km/h my record on a K4 http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif ;
<HR></BLOCKQUOTE>

Where, when and how did you manage that ?!?! I'd like to know http://ubbxforums.ubi.com/images/smiley/784.gif

Also, anybody got any tips for prop pitch + max speed on a TA152?

cheers

Andrew

http://home.comcast.net/~nate.r/ta152Hns-2.jpg

ElfunkoI
04-25-2004, 05:21 AM
The Ta use 80-88% prop pitch. Just leave it set.

In 109 I used manual to achieve higher RPM when I run lower power setting (on climbout). 100% power doesn't give best RPM. But in combat I now switch to auto becuase running at 110% power does give best rpm.

Lots more to say but I have to go to work.

"A6?http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gifhttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gifhttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif Will be A6!"

TheKetamineKid
04-25-2004, 10:03 AM
AAAHHHH my favorite topic

Firstly dont listen to anyone who says its not worth using manual on the 109 190 etc. Ive been using it for ages and there is a noticable difference when climbing, taking off etc. If you're in a bit of a fix u can use it to squeeze out some extra acceleration that auto pitch wont allow. I tend to keep it on all the time, a nice trick is to keep the throttle at 100% and just use pitch to alter speed remembering to open the rad when you give it a nice blast at 85% pitch. Most of the people here who say not to bother or that it makes no difference just dont know how to use it properly. Just spend a lot of time practicing and youll never go back.

As for whether it is historical...i'm sure 109 pilots used it in the same manor, ie when trying to get the most out of the engine.

Full real= manual pitch.

"Full real? How can you call it full real when you're still using auto-pitch on that 109!"

Mitlov47
04-26-2004, 10:58 PM
Thanks for the info, everyone. I'll practice a bit more in a week when my exams are over and I have time to fly again...

http://www.onpoi.net/ah/pics/users/387_1082406218_spitfiresigsmall2.jpg

Fehler
04-27-2004, 12:58 AM
First, let me preface this by stating that I do not possess source documentation on specific handeling of the DB engine, but I have read (Although I dont recall where) and others have posted information on use of the Kommandgarant (SP?).

Historically, the Kommandgarant (SP?) was designed to minimize pilot interface, creating a lessened workload on him during combat. Specifically, it aided the pilot in defeating runaway prop. That is not modelled in this sim, but here is an example of it: when diving, air forces the prop to spin faster and faster. Eventually the speed of the prop causes the engine to exceed the mamimum allowable RPM and poof, you blow the engine. In real life the KG was the safest and easiest system - switch it on, dont worry. Even constant speed props had to be monitored for runaway, as the mechanism would eventually be overcome by the driving force of the air past the prop blade. This situation is not modeled in the game, but in real life the German system clearly played to the 109 pilot's advantage.

The KG could be turned off and there were procedures for such an event. Usually, manual pitch was used to assist takeoff in a heavy configuration (Bombs, fuel), or when the 109 was deployed to a short runway airfield. Because of this, it is clear to see that the pilot could use it for an advantage; giving him more power when needed.

There were specifications for it's use with each different Diamler Benz engine, according to the maximum RPM of them.

In the game, the problem we have with the system is that is can be used (By a smart pilot) to give gains in climb, as long as the pilot understands the maximum RPM his engine can take and the duration it can withstand. It is a two edged sword however, because the engine will overheat faster, and there is always the possibility that you can over twist the engine and cause failure.

The ultimate question one should ask is, are the gains or increases in performance historical? Could a crafty pilot expect to see the same gains in real life as you can in this game, if that real-life pilot used manual pitch? Did any real life pilots use this in combat, and can those same procedures be duplicated in the game?

The fact is, the Germans spent a lot of time developing their prop systems to give their pilots an advantage by lessening the work load in combat. But in this sim, the disadvantages seem to sway against the German systems, but on the other side of the coin, certain advantages can also be gained with the use of manual pitch. Again, I know you could get performance gains, but for how long? What about the life of the engine itself?

Similarly, why is there no ill effect for running a CSP prop at 100% forever?

The people that ponder why the German system can be manipulated for unrealistic performance gains (IF they really are unrealistic) dont seem to question the lack of runaway prop, or the ill effects of running that prop at 100% all the time in their favorite ride. At 100%, you would see the CSP overcome in a shallow dive rather rapidly. But you can stand on your nose in the sim at 100% with no problems until your wings fall off.

If they fix one, they should fix them all. Complex Engine Management in this sim is not too complex, and the advantages of the automatic systems, like in the case of the Diamler-Benz, do not play to the favor of the pilot by virtue of the associated disadvantages of Constant Speed Prop systems.

I hope that helped answer your question. Butch2k should chime in and give you exact data, as I bet he actually has this information from original technical manuals.

http://webpages.charter.net/cuda70/FehlerSig.gif
http://webpages.charter.net/cuda70/9JG54.html

polkku
04-27-2004, 01:25 AM
Exellent point Felhler about Constant Speed Props. I have been also wondering, why it is said it is more complicated to use CSP since you don't ever have to touch it. With 100% prop you always get the best performance and are in no risk of damaging the engine even in a long steep dive with full throttle. Can someone tell me what that adds to the workload of the pilot?

with 109 you have the option to turn off prop automation and burn your engine in few seconds or gain a few more RPM's if you know how. That's all.

WUAF_Badsight
04-27-2004, 01:36 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Extreme_One:
I've asked before about the historical aspect of using Auto prop pitch but had no reply.

It seems strange to me that the feature was built into the plane and the first thing that the pilot did was disable it?!?

I'd really like to know more about this...
<HR></BLOCKQUOTE>

ANSWER :

is it easy for you to control now ? no

& they had more finer controls to be awear off than we do

Tully__
04-27-2004, 07:17 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by polkku:
Exellent point Felhler about Constant Speed Props. I have been also wondering, why it is said it is more complicated to use CSP since you don't ever have to touch it.....<HR></BLOCKQUOTE>

In the game. In real life most constant speed propellors will over rev the engine if you exceed max manouvering speed (about 2/3 - 3/4 of Vne, depending on aircraft type). You actually need to pull throttle back in steep dives to keep the engine within safe RPM limits in most RL aircraft.

=================================================


http://members.optusnet.com.au/tully_78th/legalsig.jpg

IL2 Forums Moderator
Forum Terms of Use (http://www.ubi.com/US/Info/TermsOfUse.htm)
Tully's X-45 profile (SST drivers) (http://members.optusnet.com.au/tully_78th/fb.zip)

Salut
Tully

BaldieJr
04-27-2004, 07:43 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by EMitton:

1) Do you use manual prop pitch, or leave it on auto? If you use manual, do you leave it on manual all the time, or only switch it to that for certain circumstances? <HR></BLOCKQUOTE>

Manual, all the time.
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
2) Do you use it on just the BF-109, or any other planes?<HR></BLOCKQUOTE>

All planes.
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
3) Are there any significant uses for it besides the climbing-more-quickly example I gave?<HR></BLOCKQUOTE>

Yes. Engine-safe high speed dives. Fuel economy. Best power comes at specific rpm. Short duration speed bursts are possible. Speed dumping.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
4) What do you do with the throttle when you're manipulating prop pitch? Leave it at 80? Leave it at 100%? Manipulate it as well?
<HR></BLOCKQUOTE>

Throttle and pitch tend to move together. Its like trim and control surfaces. For best results, alter one when altering the other.

The best thing to do is to read the manual on CD2 and find out where your plane makes best power (rpm) and where it cruises. Then practice with those settings. On long missions, you'll need to know best cruise, otherwise you'll run out of gas. In combat, you'll want to know how to get best speed, quickest acceleration, and quickest decceleration.

Ignore the web links and books about real-life operation. Instead, learn the guages of your favorite bird and test different settings. Its boring, but learning the hard way means learning the right way.

<pre class="ip-ubbcode-code-pre">
______ _____
(, / ) /) /) , (, /
/---( _ // _(/ _ / __ ,""""]
+----/ ____)(_(_(/_(_(__(__(/____/__/ (__--------,' /---+
| / ( / ,' NR / |
|(_/ ..-""``"'-._ (_/ __,' 42 _/ |
+-.-"" "-..,____________/7,.--"" __]-----+

</pre>

JG14_Josf
04-27-2004, 01:15 PM
ICAS track comments (http://forums.ubi.com/eve/forums?q=Y&a=tpc&s=400102&f=23110283&m=242106863&p=1)

bf109.com (http://www.bf109.com/frameset.html)

From the 109G2 Pilot manual are:

3) Switch on automatic pitch control (on the starboard side in the cockpit near the foot pedal) and master switch for the pitch adjustment system (on the primary electrical panel). Set the change-over switch underneath the throttle lever to "Manual" (Handverstellung).

Check that the blade pitch control works using the thumb switch on the throttle lever. Leave the airscrew pitch in the 12 o'clock position.

Set the change-over switch to "Automatic" (automatik ein). The airscrew pitch indicator should move to 12:30 o'clock. If the blades move further, the battery voltage is too low. If you cannot replace the battery, the change-over switch must be left on "Manual" at less than 1,900 RPM.

Generator and airscrew control system: Inspected while the engine is running at around 1,900 RPM. The battery is switched off (by pressing the switch on the instrument panel), the airscrew pitch control is set to 'Manual' (Handverstellung), the pitch is changed back and forth with the change-over switch in the throttle handle and finally set back to the 12 o'clock position. The airscrew pitch control is set back to 'Automatic" (Automatik) and the battery is switched on.

A. Prepariing for TAKE-OFF.

13) Has the airscrew pitch control been set to "Automatic"?

C. Take-off

2) Set pitch control to "Automatic". If you are going to take off with the manual setting, you must drive the airscrew pitch to the 12 o'clock position.
---------------------------------------



The manual continues to refer to the prop system. But the last quote above should apply to this comparision between what the game simulates and what was real.

Specifically the words 'you must drive the airscrew pitch...'

An electric motor drove the airscrew pitch and this occured at a specific speed determined by how fast the electric motor could drive the airscrew pitch.

In the game the airscrew pitch can change instantly by switching from manual to automatic.

The 109 manual describes a change-over switch under the throttle lever that switched control of the electric motor from an automatic electrical circuit to a manual electric curcuit. In reality the physical possition of the prop blade angle does not change suddenly as it does on the game.

'Set the change-over switch to "Automatic" (Automatik ein). The airscrew pitch indictator should move to 12:30 o'clock.'

How fast does the airscrew pitch and indicator move in the game and how fast does it move in reality?

Based upon the above 109 manual and a copy of an electrical diagram it appears to me that the game simulates an abrupt change in prop pitch that was not possible in reality.

In reality if the pilot switched from Automatic to manual then no more electric current could power the airscrew pitch motor unless the pilot closed the circuit with the manual switch in one direction or the other, while in the game a player can turn on and off the Automatic switch and the game will turn the airscrw pitch from the Automatic setting to the last manual pitch setting as if the 109 had a computer chip to record manual pitch settings.

In the game a player can maximize climb rates by setting manual pitch at 100 percent (default) and simply switching the Automatik ein switch on to gain RPM and then off to save the motor from over rev damage. ON/OFF, ON/OFF, and the game will allow the 109 to climb at a rate that inspires cries of 'overmodeling'.

In reality the same 'Automatik ein' switch would power the airscrew pitch electric motor while the automatic sensing devices demanding this action and then no airscrew pitch change would occur when the automatic circuit was disconnected.

In reality if the pilot chose to control prop pitch manually he would need to manually select any prop pitch settings that were contradictory to the Automatic pitch settings and pitch changes would occur at a speed defined by the electric motor RPM and load.
The real 109 did not have a memory chip nor a capacity to instantly change prop pitch.

The result of this error in modeling is such that a danger exists that did not exist and an exploit exists that was not possible.

The danger occurs if the player does not realize the need to test his previous manual pitch setting. If the player does not switch auto off and then back on quickly the engine may suffer immediate damage.
The technique of switching auto off and then on quickly can save the engine from damage if the last manual setting was 100 percent and if the plane is going fast, in the game.

The exploit is to use this Auto off/on error to maximize engine performance.

What happens if this is done for the entire flight?

In reality the engine would be behind the curve in gaining the proper aiscrew pitch since every time the pilot switched the Automatik ein switch off the airscrew would stop adjusting, and every time the pilot switched the Automatik ein switch to on the engine sensing devices would again try to adjust the Airscrew to an ideal setting.

The game simulates an Airscrew pitch in hyperactive mode going from full flat pitch to safe operating pitch back to full flat pitch like a demon on amphetamines. Forget about the abuse to the engine, the airscrew pitch linkage would come apart!

Take a look at the track files posted on the thread titled 'ICAS track comments' to see how best to manipulate the game for maximum performance in a climb with a 109.

Take a look at the 109G2 manual to see how the real 109s worked.

The future of WWII combat flight sims depends upon our understanding of accuracy. We constitute a market force.

Game or Sim?

Cyrano
04-27-2004, 01:51 PM
Success as a sim pilot depends on two things.
1. Using all your skills as a sim pilot (knowledge of your plane, knowledge of enemy plane, situational awareness,ACM's) to get into a favorable shooting position.
2. Once in that position being a good enough shot to take advantage of all your hard work.

That's it. Using Manual vs Auto is rather meaningless for success. Just my 2 cents.

Bearcat99
04-27-2004, 02:05 PM
I think it is great.... at least in the 109s... I wish we could get the option in all AC. I have found that by keeping it on auto until I get into comabt the engine will last longer. The engine will overheat in about 3 seconds if you arent careful and go too far. I have found that I can greatly enhance my speed and climbing ability using manual pitch.

<UL TYPE=SQUARE>http://www.jodavidsmeyer.com/combat/bookstore/tuskegeebondposter.jpg (http://tuskegeeairmen.org/airmen/who.html)[/list]<UL TYPE=SQUARE>vflyer@comcast.net [/list]<UL TYPE=SQUARE>99thPursuit Squadron IL2 Forgotten Battles (http://www.geocities.com/rt_bearcat)[/list]
UDQMG (http://www.uberdemon.com/index2.html) | HYPERLOBBY (http://hyperfighter.jinak.cz/) | IL2 Manager (http://www.checksix-fr.com/bibliotheque/detail_fichier.php?ID=1353) | MUDMOVERS (http://www.mudmovers.com/)

mike_espo
04-27-2004, 02:33 PM
I agree. I wish all aircraft had this option. The constant speed props never overrevv the engine. It would make it more interesting to fly the majority of the aircraft, which do have the constant speed prop..

"Fatte vede che ridemo!"http://www.flying-tigers.net/caccia%20WW%20II/g50.jpg

Kannaksen_hanu
04-27-2004, 04:17 PM
It seems that CEM is in place only in some planes. For example G.50 will overrev itself in dives easilly but is there any other? If there is, it is very rare imho. In fact in G.50 it is impossible to gain divespeeds like in real life without wrecking your engine no matter what prop pitch/throttle combination you use.

mike_espo
04-27-2004, 08:35 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Kannaksen_hanu:
It seems that CEM is in place only in some planes. For example G.50 will overrev itself in dives easilly but is there any other? If there is, it is very rare imho. In fact in G.50 it is impossible to gain divespeeds like in real life without wrecking your engine no matter what prop pitch/throttle combination you use.<HR></BLOCKQUOTE>

I think the G.50 engine cuts out due to negative g as it does not have fuel injection. I fly the g.50 very often and you must be very careful not to dive vertically cause engine will cut out. Just yesterday it happened to me. Was diving on this unsuspecting I-16 when I pull out, my engine quit.....It takes two attempts to restart by then he was on me and I was toast.....

"Fatte vede che ridemo!"http://www.flying-tigers.net/caccia%20WW%20II/g50.jpg

249th_Harrier
04-27-2004, 08:42 PM
Good info Josf. It looks like the game does NOT approximate reality after all. I think Oleg should fix this.