Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Crusher on February 27, 2006, 12:33:21 AM
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Military Channel had an episode dedicated to the FW 190.
Towards the end it showed an aging A-series FW. Then next to it was a 3/4 scale FW that an enthusiast had built.
Now, this man wanted his replica to be as close as possible. In 1981 or so, Beechcraft brought out a single point power control for engines. This man went to Beechcraft to ask if it would work on his model of the FW190. Beechcraft was amazed that the 1939 FW already had this feature and was disappointed that they could not be considered the inventors of the devise.
Is the AH FW going to have this feature updated to keep with the concept of authenticity in WWII plane modeling?
The Genious of Mr. Tank is awesome!:aok
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Historically the RPM were linked to the throttle, push it forward and both increase. However, you could over-ride this and manually control the RPM, the handle on the throttle rotated, so push/pull was throttle and twist fore/back was RPM. If HTC coded it in, we'd not be able to over-ride this.
I prefer the manual system, personally.
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Yup, manual pitch control on the Fw 190 was for emergency use only.
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so was war emergency power :P
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I meant "emergency" as in "somethings broken" - bear in mind that it is prop pitch, and not rpm that is adjusted, and the Kommandogerat can control this function more efficiently than any pilot could.
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Kurt Tank rocked
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If i wanted to be picky i would point out that K.T. didn't work for BMW... ;)
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Kurt Tank was an idiot. His plane sucks and is allied uber 50 cal fodder.
;)
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Kurt Tank was nothing compared to Sidney Camm.
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Originally posted by justin_g
bear in mind that it is prop pitch, and not rpm that is adjusted
FYI: Prop pitch was used to control RPM. The instruments in the cockpit usually indicate RPM as well, so while pitch might have been immediately affected, the general change was the RPM (or, how much work the engine was doing, and how much "bite" the prop had to take, which affected how much work the engine had to do).
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you have 2 control settings. One is manifold which controls the amount of fuel and the pressure the fuel mixture is delivered to the engine. This is the power aspect.
The next is Engine RPM a.k.a. governor control. This was a link similar to the one in your lawnmower. It sets the high limit of RPMs you wantand , more importantly, maintains that RPM at a steady state. If load conditions change, the RPM will not change ------->>given certain limits!
Remember, things were done manually back then to include rich/lean, turbo waste gate setting and RPM, Spark settings for ignition timing and trim and etc.. The pilot had a lot more to do that kept him very busy and left little time for window gazing.
The single point control greatly reduced the need to constantly trim the engine for each movement of either power or manifold levers. Variable pitch props were a rarity in WWII fighters simply because it was one more thing that could overload the pilot in combat. The term" constant speed prop" means just that. Though RPMs might vary, the distance the prop " moved" the plane stayed constant per revolution of the prop.
If all you needed was to slow the engine for a turn, the single point control was ideal as it set most other controls to preset detents. Minor (or fine)adjustments could still be made.
If the engine was malfunctioning, there would be little you could do in either single point or "normal" type controls. The only differnce in combat would be that you reduce engine power and RPM with one control. It was such a unique feature to the FW that it was overlooked for nearly 40 years.
As to the game, it would be the only series of plane in the planeset in which both power and Rpm would respond together, the rest of the planes would still require 2 buttons to do the same thing.
You ought to talk to the old 30's and 40' pilots who did all those manipulations as 2nd nature. Ask Great Grandpa about the cars that had to be hand cranked to be started and then the things he had to do while driving.
You young whippersnappers have got it far toooooo easy! :rolleyes:
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One clarification, you should be careful when you say "variable pitch props were rare" then a sentence or two later talk about "constant speed props" -- constant speed props have variable pitch, it's just that you don't set the pitch yourself, an oil reservoir does it for you.
In fact, almost (almost) every plane in WW2 had a variable pitch prop, they were mostly constant-speed props.
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in the concept of being able to vary the pitch in combat planes, it was rare. The larger multi-engine planes had several variations all controled by the pilot manually but to fighters, it added both weight to the plane and to the pilot's brain for very little effective result. You really would have to drive a Model T to begin to appreciate the conveniences of todays modern cars.
Did I mention the O2 mask controls in the things to do list? ;)
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Originally posted by Krusty
In fact, almost (almost) every plane in WW2 had a variable pitch prop, they were mostly constant-speed props.
BF-109 E3 had plain variable prop pitch. E4 had it too in the begining.
IAR-80/81(the plane in my avatar :cool: ) had the same system throughout the war.
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variable pitch control is an extra workload for a fighter pilot, every change in speed requires a pitch change to keep constant engine rpm's. Try the 109E in Il-2 and you will soon see it's not much fun. ;) The early Spitfires with the 2-pitch prop would have been even worse!
As to the game, it would be the only series of plane in the planeset in which both power and Rpm would respond together, the rest of the planes would still require 2 buttons to do the same thing.
109's from F onward had single lever operation, I believe. Later Spitfires had an "auto" position for the prop lever(fully back), which if engaged allowed the throttle lever to also control rpm's.
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Jaws, I stand by my statement. While there were some that had fixed pitch props (glaidators, for one, early hurricanes, and some others), I'd say that 90% or more had a variable pitch prop (most had constant speed props, some had variable pitch, but nearly all had some form of prop pitch control).
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Hi Krusty,
>While there were some that had fixed pitch props (glaidators, for one, early hurricanes, and some others), I'd say that 90% or more had a variable pitch prop (most had constant speed props, some had variable pitch, but nearly all had some form of prop pitch control).
Roger that. A fixed propeller wasted a lot of performance, so a variable pitch propeller (usually with a constant speed control) was a must for fighters in WW2.
With regard to single-lever controls (from http://www.hitechcreations.com/forums/showthread.php?s=&threadid=171089):
One comparative US report report on the FW190 expresses doubt on whether the command device would allow to get the best performance and economy from the engine. On the other hand, there is a detailed NACA report showing that it handled non-linear relationships of some half dozen parameters, and I believe it would be hard for a human operator to manage the engine with similar effectiveness.
However, after WW2 additional sensors were installed in piston-engined aircraft that provided the flight engineers with more data than available before (stuff like brake mean effective power gauges and exhaust temperature thermometers), and from what I've read, that really took engine management a step beyond what was possible during WW2, command device or not.
The command device, by the way, was not unique. The Jumo 213 for example had a "single lever control device" that was even more advanced than its BMW counterpart, regulating charge mass instead of boost pressure to get higher power below full throttle height.
The Allies, too, had single lever control devices. The French had employed one for the Dewoitine D. 520 even before the war, but apparently it still had some issues, judging by Eric Brown's test flight impressions. The late-war Spitfires had an "interconnected control levers" operation mode, too, which apparently worked just like a command device, at least when the engine was operating at maximum power. For normal climb and cruise situations, the pilot could override this system for better efficiency.
Regards,
Henning (HoHun)
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109's from F onward had single lever operation, I believe. Later Spitfires had an "auto" position for the prop lever(fully back), which if engaged allowed the throttle lever to also control rpm's.
Emils were retrofitted IIRC in late '40 or early '41 (before Barbarossa) and in FB/AEP/PF this is modeled for the E-series (E-4, E-4/B, E-7) etc...
I have read where FW pilots would sometimes run into problems maintaining formation due to the lack of fine tuning of power.
Justin is corrct in the the FW had a manual override of the kommandogerat for emergencies, meaning that if something went wrong with the function of the kommandogerat the pilot could switch to manual and be able to land the plane. IIRC the 'manual' setting didn't allow full control over prop pitch but it was a single pitch setting.
On Butch's AAW2 Forum forum member 'schwarze-man' made a detailed post describing the 109s system.
Some of the points he stated:
In manual the pitch of the blades is set by use of the two-way rocker
switch on the throttle (marked "kleiner/grosser"(U/min)) and by reference to the propellor pitch indicator "clock". In automatic mode the governor adjusts
the propellor pitch to give the U/min required by the throttle position.
Because the automatic control is not effective below 2000U/min , it would keep trying to drive the prop to finer pitch and could burn-out the electric motor, automatic is only selected just before take-off. In automatic the throttle position controls the engine speed and manifold pressure in accordance to the designed engine performance table.
So, how does this all look in the cockpit?
First,we must decide on the use of manual propellor or automatic propellor.
In manual propellor control (selected on the switch below the throttle-box
marked"HAND--AUTOMATIK" to "HAND") the pilot can select the prop to run
faster or slower ("GROSSER--KLEINER") by using the rocker switch on the
throttle.
I won't quote him any firther but his posts goes on to give many details.
As I understand it the single lever control on the DBs was far less complicated then the 'kommandogerat' system used on the BMWs...
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Alot of these arguements can be resolved by making sure both sides read the same reference materials. The only way to resolve this type of discussion is to have somebody that actually flew the aircraft in WWII.
It is a game, no more no less.
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That's how it worked
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The single lever system in the Fw 190 seem to be the first succesfull system of it's kind but generally all advanced engine controll systems used during war were invented long before WWII (like CO analyzers, density metering systems, variable ignition advance etc.). Practical utilization just took time.
gripen
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Here is a good article on this subject.
Constant speed is the norm in WWII. It is a special kind of variable pitch.
After reading, you should get a much better idea of why we don't need a control for prop pitch.
Props (http://www.auf.asn.au/groundschool/propeller.html)
:aok
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i would like to use this as an opporutity to bring up another old tread on FW 190s started by me, who pwns n00bs
http://hitechcreations.com/forums/showthread.php?s=&threadid=171089
still wondering about it....:huh :huh :huh :furious :furious :furious
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Personal experiance:
Running in over rich condition probably fouled sparkplugs and killed engine performance. However, in an overheat situation, it would cool the engine if left on for a minute or so. I definitely think that the over rich setting might have been used to cool the engine but it was not left on for extended periods.
14.7:1 is considered the ideal mixture setting. Rich limit would be about 12:1 and lean limit is about 16:1. Over rich would then use something akin to 10:1 and would, therefore, waste a lot of fuel as well as foul or even flood the engine.
Butwhaddoiknow!
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Originally posted by Crusher
Personal experiance:
Running in over rich condition probably fouled sparkplugs and killed engine performance. However, in an overheat situation, it would cool the engine if left on for a minute or so. I definitely think that the over rich setting might have been used to cool the engine but it was not left on for extended periods.
14.7:1 is considered the ideal mixture setting. Rich limit would be about 12:1 and lean limit is about 16:1. Over rich would then use something akin to 10:1 and would, therefore, waste a lot of fuel as well as foul or even flood the engine.
Butwhaddoiknow!
i think this is where i read stuff, its in my bookmarks for some reason
http://naca.larc.nasa.gov/reports/1945/naca-wr-e-192/
accordong to this when using Kommandogerat, the BMW was rich mix if RPM was over 2150.
my guess is that this was part of the solution to the early 190A's overheating problem & i would assume that in a desperate situation, one could go to manual mixture control, find peak & by getting the power boost, pwn some n00bs, but i've never read if anyone did this. Even if you weren't desperate, why not extend your range a bit?
odd thing i read about, the mixture was toggled lean to rich at 2150 RPM, so pushing the power lever forward from 2140 RPM to 2160 RPM would give a bit of a power loss
...another odd thing is that even a brand new Cessna 172 doesn't have single lever power control, but somehow my 11 year old ford has it operated by my foot, rofl :rofl :rofl :rofl :rofl :rofl :rofl :rofl
what is your personal experience?