PDA

View Full Version : Stress dammage and the New flight model



Osirisx9
05-01-2005, 07:21 AM
S~ First I want to say thank you to the Oleg and crew for giving us such a great sim. And get well soon Oleg. As many of you know I'm a dedicated B-25 driver but I know that I can do certain maneuvers with the B-25 as modeled that would tear the wings off or cause enough dammage to the airframe that would normally effect the handling of the aircraft in real life. Will the new FMs and DMs have this added feature. I think the possibility of overstressing your aircraft would would add some more realism to a already top notch sim. Thanks in advance.

RAF238thOsiris
www.warbirdsofprey.org (http://www.warbirdsofprey.org)

anasteksi
05-01-2005, 10:00 AM
i can remember that when i played warbirds few years ago
(and the version was 2.7? or something) it had somekind of overstress model. http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

OldMan____
05-01-2005, 10:08 AM
Fliught model has nothing to do with DAMAGE model. We would need a new DAMAGE model to do that. People are expecting to have tons of different things solved by a software artifact that only handles FLIGHT behavior of the planes!!!

Osirisx9
05-01-2005, 01:18 PM
Originally posted by OldMan____:
Fliught model has nothing to do with DAMAGE model. We would need a new DAMAGE model to do that. People are expecting to have tons of different things solved by a software artifact that only handles FLIGHT behavior of the planes!!!

Yes I understand that the FM and DM are seperate. All I wanted to know was will it be possible to dammage your aircraft by overstressing it and then have the dammage alter the flight characteristics. A good example of this would be getting my B-25s aileron shot off by a 108 therefore hurting maneuverability. But instead of having a aileron shot off ,instead it would be torn skinn, and bent or cracked wingspars(something like this could cause a seperation of airflow over the wings or failure of the wing durring one to many violent maneuvers.
Thanks.

RAF238thOsiris
www.warbirdsofprey.org (http://www.warbirdsofprey.org)

fherathras
05-01-2005, 02:00 PM
sounds good.

avimimus
05-02-2005, 07:11 AM
Yes, it would be quite good.

I have noticed that some aircraft (eg. Go-229) shed their wings in a dive if you pull up to fast so it might already be modelled.

In anycase the bomber FMs are much better in 3.00 than they were in 2.00!

WB_Outlaw
05-02-2005, 11:31 AM
Osiris,
It's already possible to overstress and damage your aircraft, it's just not as subtle as you're looking for and it only occurs at higher speeds. Flight control surfaces (tail feathers, flaps, and ailerons) and entire can be torn off the aircraft due to overspeed and overstress but that's about it. There is no intermediate range where you can permanently deform (bend) your aircraft and have it affect flight. I believe the insane strength loaded aircraft exhibit is to take into account the fact that we don't have the feedback of real flight and can therefore easily overstress them (by accidentally bumping the stick for example).

As to whether or not this feature will be in BoB, your guess is as good as mine.



-Outlaw.

Fennec_P
05-02-2005, 07:59 PM
I think that would be cool. Especially if there was audible or visual cues for overstressing (like wings flexing). It kind of sucks that your first indication of overloading is when a piece comes off your plane.

Not pertaining to this, but a related topic, Oleg said that structural damage in BoB will affect load limits.

Like, if a wing spar is damaged by a bullet, it will be more likely to collapse at high G loads than the other wing.

And also said, this damage may carry over from mission to mission in a campaign if there is not time to fix it.

heywooood
05-02-2005, 09:42 PM
hopefully - there will be an aircraft airworthiness report to review with your maintenance chief before takeoff....and for inflight damage, maybe some audble indication of a weak wing spar..if there is no visible damage in the wing, like those jagged portholes we already have but which dont stop you from looping or pulling G's at present.

BBB_Hyperion
05-02-2005, 10:14 PM
At the moment all planes hold 15gs not what i would call realistic .

Fennec_P
05-02-2005, 10:58 PM
At the moment most planes have load limits of 10G or more with a 30-50% safety margin.

It always bothers me when people expect the wings to magically fold the instant you hit the 'maximum load factor' as quoted in those internet sources, or on a little placard in the cockpit.

These are not actual structural breaking points, but simply limits that the pilot is not supposed to deliberately exceed.

Think of them as a submarine crush depth. The submarine does not instantly implode when it reaches it's quoted crush depth. Most of the time it can dive 50% deeper or more perfectly safe, but the builders put the crush depth unrealistically low to avoid accidents, or as a safety buffer in case of defects.

In fact, if you look at a aircraft pilots operating handbook, it will actually tell you the safety margin on the same page as the load limits. IIRC, it's 1.5 x the limit load factor.

A quote from: http://www.whittsflying.com/Page3.21Pilots%20Operating%20Handbook.htm

Ultimate Load Factor
Ultimate load factor is the limit load factor multiplied by 1.5 to provide an additional measure of safety. While structural damage occurs at the limit load factor, structural failure will not occur until the ultimate load factor is reached.

So if the little sign in the cockpit says not to exceed 10G at a certain speed, you could do 15 or more before the wings actually come off.

And don't tell me you can't do 15G. You can do G loads up to 20 in some planes for short periods of time before you black out.

If planes actaully shed wings at the 'limit load factor', you would have all of the planes dying this way, since most players exceed it on a regular basis, as did pilots IRL.

At a guess I'd say it's quite realistically portrayed in FB. It's only really possible to destroy your plane at high speeds near your Vmax. At these speeds, it takes much less than 15G.

WWMaxGunz
05-03-2005, 02:22 AM
If planes accumulated stress damage without showing very soon or forbid the realism of
starting with a used plane with engine and frame wear and then later during some less
stressful than the last 6 moves something breaks? So many of 10 players immediately
post a bug notice post, then go to HL and start a new religion theory on IL2 bias/cheat.
10 minus so many out of 10 regular forum members understand but the newbies don't and
the syncophants don't and the new 'fact' spreads to become like a political true lie.
No game maker needs that. Though perhaps an Option that you have to switch on would
cut the number to half so many, or I am being optimistic.

BBB_Hyperion
05-03-2005, 03:48 AM
http://www.butcherbirds.de/hypesstorage/p51gloadi.jpg

As you can see Wing Breaking point is 10.7 g . PlaneLimit US 7.1 g
PlaneLimit Swiss 4 g

Limit to wing break is indeed about x1.5 for US here. I read somewhere even 8 g limit but not sure if that was wartime limit.

As far as i understood it when a force of over 10.7 g is working on the wing /s its not that good so where are the 15g that must be splits of a second ?

Another point is maybe from which location you calculate the gs . On CG , on Pilot, on 3d center .

Most WWII planes had a wing breaking point from 6g to 11g . Deforming surely starts below breaking point.

But i am sure waiting for 20g charts for wwii planes wings and some pilot comments that they didnt black out at 20g http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

quiet_man
05-03-2005, 12:53 PM
I once read something about a WWII plane that had its wingtips designed to break at 9g to prevent critical wing failure

anyone remembers which plane?

quiet_man

Hristos
05-03-2005, 03:13 PM
Originally posted by quiet_man:
I once read something about a WWII plane that had its wingtips designed to break at 9g to prevent critical wing failure

anyone remembers which plane?

quiet_man

I think Bearcat had something like that, but me thinks it was to speed, not Gs.

WB_Outlaw
05-03-2005, 04:35 PM
Originally posted by quiet_man:
I once read something about a WWII plane that had its wingtips designed to break at 9g to prevent critical wing failure


It was the Bearcat but it didn't work very well b/c one would break before the other. I believe that "feature" was removed very early on, maybe even before serial production began.

-Outlaw.

Heinz_Schuss
05-03-2005, 09:42 PM
In Janes WW2 Fighters they already had airframe stress noises and possibly breakage if certain limits were exceeded. It sounded great to hear your machine creaking as you piled on the Gs and looped etc.

I never thought IL-2 wouldn't have it... until I played it. What an oversight!

Schuss

Fennec_P
05-05-2005, 03:58 AM
Oversight? Why should you hear the wings creak? You can hardly hear your own gunfire.

IRL, the first indication that you have exceeded limits was when you land, and your boss yells at you for breaking the plane.

It is 'Hollywood' feature, be sure.

hawkmeister
05-06-2005, 06:03 AM
Originally posted by BBB_Hyperion:
http://www.butcherbirds.de/hypesstorage/p51gloadi.jpg

As you can see Wing Breaking point is 10.7 g . PlaneLimit US 7.1 g
PlaneLimit Swiss 4 g

Limit to wing break is indeed about x1.5 for US here. I read somewhere even 8 g limit but not sure if that was wartime limit.


Yes - this is correct. But the ultimate load as a factor of rated load varied from country to country and service to service as a requirement for their production airplanes. There was no one single rule that applied to all.

The A6M is a great example of what I mean. I don't recall the exact figures off the top of my head so please keep this in mind - this is just an example. The design spec for the A6M called for something like +7G rated. The usual IJN requirement was for something like 1.5 times this before suffering a structural failure, but because this requirement would have made it impossible for Mitsubishi to meet the navy's performance requirements the IJN allowed a waiver of this 1.5 factor for something more like 1.2. So the rated load of the plane was very similar to other nationality's fighters but the ultimate load was very different. It also was the prime factor contributing to the Zero's reputation for weakness - even among Japanese pilots.

The FAA requirement for general aviation aircraft ultimate load factors is 1.5, if I'm not mistaken. Been far too long since my last biennial.

-Bill

Heinz_Schuss
05-06-2005, 09:10 PM
Yes, but since we can't feel the Gs, it would be useful to hear them. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

BBB_Hyperion
05-07-2005, 01:56 AM
Didnt know i claimed a ultimate loadfactor as 1.5 i said it fits in this case. 10.7 / 8 g is 1.3 loadfactor i mentioned too. My point was the g max levels for wings http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif Where 20g or 15g is little off. But nice to hear other plane limits are in same margin too .