FE2 MaxG Parameter

[Mike Dora 171]

Does anyone happen to know what would be typical maximum G factors for WW1 airframes?

 

I'm asking because it has long kind of bothered me that many/most FE2 (& FE1) aircraft seem to have MaxG parameters of 5 or more, yet from WW2 aviation literature I've read that pilots tended to black out around 4G, which is why the British & Americans were developing g-pants by the end of that war. Even with g-pants, a novice can still black out between 3 & 4G (I know.. ;).

 

So what do people think? Does anyone have details of specific maximum G limits for specific WW1 types (we know they did static load tests on prototypes), and even if they did, are these relevant to the sim when in real life the limiting factor may more likely have been the pilots' G-tolerance? The latter issue is making me think that maybe a generic MaxG value of, say, 3.5-ish may actually be the most appropriate for most types, with something lower for the "heavies".

 

Mike

[+gterl 1,204]

Good question and I had to look this up. Remembered a threat in the Aerodrome Forum and finally found this

 

Checking airframes during the war was done through static sandbag load testing, and this method often did not replicate dynamically-generated failures caused by aerodynamics.

This was basically the problem why the Germans did not isolate the Albatros V-strutter's oscilating lower wing flaw.

 

Flying Experiments conducted during the war by the British (RFC/RAF) and for some of these they used a device called accelerometer

 

Out of the Aerodrome -> Original link -> http://www.theaerodrome.com/forum/showthread.php?t=13979

To help create a historical baseline, Germany's Idflieg (Inspektion der Fliegertruppen) specified a static wing load rating of 4.5G's (4.5 times the plane's fully loaded weight), during the period 1915-1917.
Prior to the war it was recommended that an acceleration of 3G's could be expected during common aerobatic flight maneuvers, and a safety factor of 2 times was agreed upon for an ultimate load factor standard of 6G's (this was also accepted for military aircraft).
As the war progressed, and as additional data was deemed useful for aircraft development, mock combat tests were performed by the British using a number of aircraft types. In these test the SE5A fighter recorded load factors of up to 4G's (3.8G's while looping), and it was found that 3G's was quite common for typical manuevers. It was also noted that bumpy weather could cause accelerations of +/- .5G.

 

Charts

 

[Mike Dora 171]

Thanks Gterl,

 

That helps a very great deal. To expand on my thinking, I recall from earlier training and later reading that typically modern airframes (= anything from at least WW2 onwards) tend to be stressed to about 1.5x the anticipated in-service load factors. So if you expect an airframe to typically pull 3G, you build it to stand 4.5G and so on.

 

This chimes in well with the German specs above, when one bears in mind that the pilot would not be able to physiologically tolerate more than 3-4G.

 

Where I am going with all this in the case of FE2 (& FE1 too), is that the virtual pilots all seem to adhere to the MaxG limits for the planes they are "flying". With typical MaxG levels well in excess of 5G, this may be why we see Camels, Tripes etc zooming around like F-16s.

 

In this context therefore, as mentioned above I'm thinking that a MaxG=3.5 might be the most appropriate for most types, with MaxG=2.0 for the heavies (sidebar: even the famously maneuverable Avro Vulcan was limited to 2G in service).

 

That may make sure that all the virtual pilots stay within human physical limitations, but would leave the question of how the human pilot (the player) becomes aware of approaching the G-limit.

 

Which leads to the next sim-technical issue. Does anyone know how the Options.ini file "Blackout" parameter works? What do Blackout=0, =1, =2 mean? And also, can we set the Blackout-initiating G-parameter, and if so, how?

 

Cheers

 

Mike

[+gterl 1,204]

Limitations set within AIRCRAFTOBJECT.INI (within the objects Folder)

 

[PilotGLimits]
BlackoutStartG=4.0
BlackoutAmount=0.01
RedoutStartG=-2.5
RedoutAmount=0.05
RestoreRate=0.05

[+VonS 1,424]

Stimulating technical questions gents', with real implications in FE/FE2. In my revised FMs, I've gone for a spectrum of possibilities, ranging from about MaxG 2.5 for the very early types, to about 5.5 or 5.8 MaxG on the late-war types like the Viper Se5a, the Phonix, etc.

 

I've also noticed that planes where MaxG values exceed about 4.3 to 4.5 tend to be very acrobatic in flight - the AI of course doesn't "black out" in such maneuvers. Mike's suggestion of a limit of about 3.5 MaxG seems about right to avoid the AI engaging in excessive maneuvers - this of course will require that the human-flown types are also handled more gently - especially if you include MaxG values for all lift surfaces of no higher than about 3.5.

 

Lowering the MaxG values across the types will also result in more structural failure even for the AI-flown types, post-damage. I will leave my specturm of MaxG possibilities in place as I go forward with the FM updates, but this is an area worth experimenting with.

 

Another possibility is to lower Structural Factor numbers across lift surfaces - this may also tame the AI flight behavior on some types, and will also increase the risk of structural failure, even without tweaking MaxG values.

 

Happy flying,

Von S

[Mike Dora 171]

Thanks Again Gterl,

 

Those AircraftObject.ini PilotGLimits parameters are exactly the same as the corresponding parameters for SF2. This is suspicious - the typical SF2 aircraft type is a modern jet where the pliot would be wearing g-pants and so would have enhanced G-tolerance. So those levels cannot be right for WW1 aircrew. I suggest that figures like these may be more appropriate for FE2/1?

 

[PilotGLimits]
BlackoutStartG=3.0
BlackoutAmount=0.01
RedoutStartG=-2.0
RedoutAmount=0.05
RestoreRate=0.05

 

For VonS, further to our PM discussions, I'm thinking that if we set MaxG=3.5 for most all types, then for the V-strutters we could set the lower wings' MaxG at, say, 3.2-3.3.

 

Then when flying Albatri or Nieups, if you start blacking out and hear the wings creaking, it's time to unload! -    before the airframe unloads a lower wing...

 

Cheers

 

Mike

[+VonS 1,424]

Hi Mike,

 

Yes, your MaxG values look realistic - have now looked into my latest update for the Albatri (ver. 8.7). I have values, for example, for the Alb D.5 (160HP version) - the most "fragile" supposedly of the v-strutter Albs. - ranging from MaxG 4.4 for the top left and right wing to MaxG 4.0 for the bottom left and right wing, including MaxG 3.9 for bottom left and right wing tips. For the slightly more robust Alb. varieties (D.3, 5a), my values range from about 4.0 to 4.6, etc. - and slightly above 5.0 for the D.I and II types.

 

I also see that the structural factor value for the top left and right wing is 1.2, while there are no structural factors implemented for lower wing panels (meaning that they default to 1.0) - this is for the Alb D.5 (I have reduced structural factor numbers only on a few of the types, where I noticed that they were too high in the 4-6 range). Ideally, structural factor numbers for the WWI types should not exceed about 3.5 or 4 - otherwise it's excessive. I look forward to more of these experiments. Will also try out the lower PilotGLimits you've included - they look much more realistic.

 

Happy flying,

Von S