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zugfuhrer
04-08-2004, 05:34 PM
When I have manual pitch 100% in ME109 the engine blows.
When I have manual pitch in a Spit, La lagg etc and use 100% pitch it seems to set the engine to optimal rpm.
The FW doesnt over rpm with 100% pitch. Where there different systems in Fw and Me?

zugfuhrer
04-08-2004, 05:34 PM
When I have manual pitch 100% in ME109 the engine blows.
When I have manual pitch in a Spit, La lagg etc and use 100% pitch it seems to set the engine to optimal rpm.
The FW doesnt over rpm with 100% pitch. Where there different systems in Fw and Me?

bodaw
04-08-2004, 07:00 PM
Most of the Fw series have the governor so as not to over rev. The Me series does not have one, hence the blow up.

BuzzardHead
04-08-2004, 07:04 PM
FW-190 is a radial engine aircraft,while the BF-109 is a V12.Both aircraft however utilized auto-prop pitch.TO keep from over reving in manual prop setting first close trottle then change to manual.

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Maple_Tiger
04-08-2004, 07:38 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by zugfuhrer:
When I have manual pitch 100% in ME109 the engine blows.
When I have manual pitch in a Spit, La lagg etc and use 100% pitch it seems to set the engine to optimal rpm.
The FW doesnt over rpm with 100% pitch. Where there different systems in Fw and Me?<HR></BLOCKQUOTE>


Alied planes do not have manual prop pitch, ther CPS planes. http://ubbxforums.ubi.com/images/smiley/35.gif

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WWMaxGunz
04-08-2004, 07:39 PM
It depends on if you are in manual or automatic mode in the 109's and I'm not entirely sure if all 109's have the same setup. Same with the 190's, not all are CSP IIRC. Ask Butch.

And, Ise... it flat out amazes me that you don't know the systems down to the nomenclature and details along with every revision that hit! Well I guess you had to save something for laters. Now's the time!


Neal

crazyivan1970
04-08-2004, 09:13 PM
Ok..this belongs in general discussion.

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pinche_bolillo
04-08-2004, 09:41 PM
once you figure out how to cycle the prop pitch on the 109 you will be amazed at the boost it gives you. no other a/c in this game gets a boost like the 109 does on manual.

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VW-IceFire
04-08-2004, 10:49 PM
The 109 is great on manual but I usually overrev and blow it up. I prefer the CPS props that exist on the allied aircraft where you essentially control RPM and not the pitch specifically.

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GK.
04-08-2004, 11:34 PM
The secret to not over-reving your engine is putting your prop pitch on a slider.

It is possible to blow out an fw engine with prop pitch. Put it on 100% and dive to the deck vertical from 3k+, see what happens.

AnaK774
04-08-2004, 11:39 PM
Only in Doras and TA, A models seem to b immune to overrev

Tully__
04-09-2004, 01:05 AM
The manual pitch control on (most of?) the 109 series is direct control of the propellor pitch. If you set it fine (low angle of attack for the propellor blades), the propellor presents less drag and the engine can spin it faster. Setting it coarse turns the propellor blades to high angle of attack causing lots of drag and slowing it down.

The idea is to set the pitch so the engine is operating for best power or best cruise, depending on circumstances.

In most of the allied aircraft the propellor is a constant speed propellor (CSP, not CPS as most type). The pitch control doesn't set the pitch directly, it sets desired engine rpm. The constant speed propellor governing unit then changes the propellor pitch to achieve the desired rpm at the current speed and power setting.

There's a good article about this at Pelicans Perch (http://www.avweb.com/news/columns/182082-1.html) on the AvWeb site.

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IIIJG11Ivank
04-09-2004, 03:48 AM
Seems this comes up about every 3months or so.

The German prop pitch systems are different to the Allied system. In the case of the 109 from the E4 (or about) an Auto prop pitch system was employed. In auto the "System" automatically seleced a specfic RPM for each ATA setting the pilot set. Then this RPM was governed. This system can be thought off as a "Variable datum Contant speed system" (Thanks Chris for this term). The datum ATA is set by the pilot the RPM is then controlled (Governed) to an optimum value refrenced to this ATA datum. If manual is selected then the prop becomes a straight out variable pitch prop. The pilot selects a blade angle then its fixed. If TAS changes then prop RPM will change but pitch is fixed. This = real Engine overspeed potential. If ATA is changed then RPM will also change. In simple terms the 109 system was all controlled by a clever combination of prop loading, ATA regulation and aerodynamics.

The FW190 Had a much more sophisticated system. The system that did all this was called "Kommandgerate" (For those that understand like a piston engine version of FADEC). Amongst other things (like timing, mixture etc) it also Selected an RPM for a pilot selected ATA. So for each ATA demanded by the pilot the Kommandgerate provides a governed RPM value. In The FW190 the selection of manual was for Emergency use only, and resulted in straight out variable pitch operation over a limited range.

Allied aircraft used a Constant Speed system. In this system the pilot sets a specfic MAP/Boost and an appropriate RPM for that boost. This requires Two levers to be moved. Within limits the Constant Speed Unit (CSU) will maintain the pilot selected RPM, this is called Governing. On some late war aircraft (Spitfire VIII,IX, P40N, P63 etc). The pilot could mechanically link the throttle to the prop lever. Thereby producing a psuedo Single lever system "similar" (but much less spohisticated) to the German system. You push the throttle up the prop lever goes up too, so in effect Boost/MAP selects an appropriate RPM which is governed to that value as TAS changes. The Throttle or MAP/Boost v RPM all being determined by mechanical calibration of push rod lengths etc.

FB and All this
Some claim they can get better performance using manual in Luftwaffe aircraft. This might be so but comes at significant increased pilot workload, with great potential to overspeed the engine. So unless you really have your Sh-t in one pile leave it in auto. Either way I believe the performance gains are marginal (IMHO .... stands by for flamewherfing http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Credits: Thanks to Chris Starr for his countless written words sent to me on German prop pitch systems. Far more detailed than this simple explantaion. Chris is the resident expert on all this.

[This message was edited by IIIJG11Ivank on Fri April 09 2004 at 02:59 AM.]

ZG77_Lignite
04-09-2004, 09:29 AM
Excellent description IvanK, however I would disagree on one minor technical point. I believe the FW190 (-A series at least, I'm unfamiliar with -D and Ta-152) does use a 'real' constant speed prop, in conjunction with the Kommandergerat (which is what is modeled in FB at this point).

I believe it had a pilot adjustable governor (relfected in FB with 'manual mode') AND an 'emergency' electric-over-hydraulic pitch control (which would be like the FB 109), in case of CSP governor failure. This is similar to many other CSP aircraft, the P40 and P38 being examples I believe. This 'third' system for prop control on the FW190 or any aircraft (it being an 'emergency' system) is not modeled in FB currently.

This is mainly gleaned from the NACA report on the BMW801D-2. I could certainly be wrong, but this report details the operation of the Kommandergerat, and imho this appears to be how it operates. If so, FB gives a very close approximation of how the Kommandergerate system works.

IKP_Hawk
04-09-2004, 09:39 AM
These are my CSP settings for the spit.

-------------------------------------Boost---------------Temp.?c
------------------ R.P.M. -----------Lb/Sq.in.-----------Clnt.---Oil

Max.Take-off
To 1000 ft-------3000---------+12 1/2(+7)-------------------

Max.Climbing
1 Hr. Limit--------2850---------+09-----(+7)---------125----90

Max.Rich
Continous--------2650----------+07-----(+5)---------105----90

Max.Weak
Continous--------2650----------+04-----(+4)---------105----90

Combat
5 Mins.Limit------3000----------+12------(+7)--------135----105

115?C. permitted for short periods if necessary.

Note: Combat boost is obtained by operating the
boost contol cut-out and is effective up to 10,500 ft

[This message was edited by IKP_Hawk on Fri April 09 2004 at 10:04 AM.]

GK.
04-09-2004, 09:43 AM
fw190a models blow out trust me ive done it. i think the dive must be much steeper than in a dora but its very possible. put pitch at 85% just to be sure.

BlindHuck
04-09-2004, 10:01 AM
I believe all german props were electric. Never heard of hydraulic/electric props. Sounds interesting.

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ZG77_Lignite
04-09-2004, 01:50 PM
That is a mis-statement on my part, where I live, 'electric over hydraulic' refers to hydraulic valves controled by electric solenoids. That is not what I meant above. Above I intended to say the constant speed prop pitch governor is hydraulically controlled, while the emergency pitch control is electric.

From the NACA report on the BMW801D-2 (refering to the Kommandergerat system):

'Engine speed is maintained constant by means of a fly-ball governor and an incorporated servopiston valve. The Loading of the governor is determined by the position of the main-servocontrol lever. For each governor loading, propellor pitch will vary through a range of values; the exact pitch depends on airspeed and air density...'

And: '...'Emergency control over propeller pitch is also provided by an elctrical propeller-pitch control, which is manually operated. The elctrical propeller-pitch control, however, does not provide automatic regulation of the propeller pitch for constant-speed operation of the engine.'

Later in the report, it refers to the Servo Oil system, which is what provides 'power' (hydraulic power) for the CSP pitch control. As a side note, this oil gear pump could not produce pressure at altitudes above 32000ft (according to NACA), so the constant speed prop (as well as many other of the Kommandergerat functions) would not operate above these altitudes. I believe this to be an older variant of the BMW801D-2, and this pump was probably improved by Germany later in the war.