Daidalos Team's Room -QUESTIONS AND REQUESTS ONLY - For 4.11

[Pursuivant]

Originally Posted by SaQSoN

As someone here has already said, gear dropping is a result of landing gear leg upper lock damage (which was holding the leg in retracted position). It has nothing to do with hydraulic system damage (or damage to any other system, used to operate the gear).

Damage to the gear lock could also explain a gear dropping, as could excessive G-loads or severed cables, but I still hold that the main reason that gears, flaps and other plane parts dropped when damaged was due to hydraulic failure. Obviously, though, it depends on the plane and in the heat of combat the exact cause was often impossible to figure out.

In some cases, however, damage to the hydraulic system is so obvious it has to be the cause for gear drop.

Example: Starting at 0:32 in this video, you can see a fire on the oleo struts of the Hurricane as the hydraulic fluid burns away. Fire is localized and burns out quickly once the fluid is gone. (Actual damage to the hydraulic lines/pump was probably earlier, since smoke from the area becomes visible at around 0:30.)

http://www.youtube.com/watch?v=_aqJwHdMDK0

More examples of shot-up planes dropping landing gear in a fashion consistent with hydraulic failure (and video of the mod I mentioned):

http://www.youtube.com/watch?v=dvlG9fY9g2Q

[SaQSoN]

Originally Posted by Pursuivant

Damage to the gear lock could also explain a gear dropping, as could excessive G-loads or severed cables, but I still hold that the main reason that gears, flaps and other plane parts dropped when damaged was due to hydraulic failure.

All planes with retractable gear had 2 gear locks (one for each gear position) for each gear leg. And ONLY this locks were holding the gear in terminal positions, not hydraulic, or air pressure, or mechanical force from gear actuator (depending on how the gear was operated). The pressure was sent in the system ONLY when the gear was either retracted, or extended.
So, I repeat again: gear drop can be caused ONLY by lock damage.
However, it is quite possible, that hydraulic, or pneumatic lines, or whatever lines were used to operate gear could be damaged as well at hte same instance, as the locks, since they were usually located near the locks. Yet again, their damage is not related to the effect of gear drop.

PS Hydraulic fluid doesn't burn. The fire was probably from small fuel tanks, located on the front edge of Hurri wing. There is nothing in the video, that may hint, what caused the gear to extend.

PPS And after reading Hurri operating manual, I tend to believe, that in this particular case the pilot under attack occasionally engaged emergency gear down pedal, which releases the upper gear lock and lets gear to drop down under their own weight.

[Tempest123]

Originally Posted by SaQSoN

All planes with retractable gear had 2 gear locks (one for each gear position) for each gear leg. And ONLY this locks were holding the gear in terminal positions, not hydraulic, or air pressure, or mechanical force from gear actuator (depending on how the gear was operated). The pressure was sent in the system ONLY when the gear was either retracted, or extended.
So, I repeat again: gear drop can be caused ONLY by lock damage.
However, it is quite possible, that hydraulic, or pneumatic lines, or whatever lines were used to operate gear could be damaged as well at hte same instance, as the locks, since they were usually located near the locks. Yet again, their damage is not related to the effect of gear drop.

PS Hydraulic fluid doesn't burn. The fire was probably from small fuel tanks, located on the front edge of Hurri wing. There is nothing in the video, that may hint, what caused the gear to extend.

PPS And after reading Hurri operating manual, I tend to believe, that in this particular case the pilot under attack occasionally engaged emergency gear down pedal, which releases the upper gear lock and lets gear to drop down under their own weight.

+1 for this, and if a hydraulic line was hit, but the up-lock was not, the gear could often be extended to engage the down-lock position via the aforementioned emergency system, where the pilot could extend the gear by using gravity, a hand crank or other "blow down" system. Of course if the gear falls out but doesn't lock down, you'll have a bad situation. It would be neat to see some of this in Il2, but I think there would be many other systems that would need to be modeled.

[EJGr.Ost_Caspar]

Additionally a lucky hit could inflict the electric/hydraulic system in a way, that the gear lowers normally but unintended, just as if the pilot would have pushed the lever.

"So always do aim with your 20mm for that little switcher on the left panel!"

[Tempest123]

I always aim for the altimeter

[Lagarto]

Originally Posted by EJGr.Ost_Caspar

Additionally a lucky hit could inflict the electric/hydraulic system in a way, that the gear lowers normally but unintended, just as if the pilot would have pushed the lever.

"So always do aim with your 20mm for that little switcher on the left panel!"

Soo... did we inspire DT's interest in the issue?

[Azimech]

Originally Posted by SaQSoN

PS Hydraulic fluid doesn't burn. The fire was probably from small fuel tanks, located on the front edge of Hurri wing. There is nothing in the video, that may hint, what caused the gear to extend.

I'm very sorry but hydraulic fluid does burn, if sprayed under high pressure even very violently, both mineral and synthetic types. Sometimes I use old fluid in my garden torches.

[Pursuivant]

Originally Posted by SaQSoN

So, I repeat again: gear drop can be caused ONLY by lock damage.

I think you're generally right, but I also think that there are causes other than damage which might make the lock fail, or fail to engage in the first place. A combination of wear, vibration and/or poor maintenance could set up a situation where lock barely holds the gear in place, so that it drops when the hydraulics are hit.

The paradox, though, is that there is gun camera footage which shows both landing gears dropping in a pattern consistent with loss of hydraulic fluid. Otherwise, it would have to be a very lucky hit indeed to take out all the locks on both gears at once!

Others have pointed out that cockpit or electrical system damage could cause gears to come down. Also, as you point out it's possible that pilot error (hitting the wrong button) could also cause the gears to deploy.

Originally Posted by SaQSoN

PS Hydraulic fluid doesn't burn. The fire was probably from small fuel tanks, located on the front edge of Hurri wing. There is nothing in the video, that may hint, what caused the gear to extend.

In the case of the Hurricane, I think that you might be right, assuming the Hurricane was relatively low on fuel so that the other fuel cells didn't catch fire.

But, hydraulic fluid can burn if you use the right liquid! For example, during the Cold War some Soviet planes used alcohol as hydraulic fluid (doesn't freeze as easily at high altitudes). As a result, they had a problem with readiness as ground crews were prone to siphon off hydraulic fluid for illicit, unintended, purposes.

Anyhow, I think we're both in agreement that, regardless of origins, it would be nice if landing gear drop and hydraulic/pneumatic system failures were modeled in the game.

[Jumpy]

Anyhow, I think we're both in agreement that, regardless of origins, it would be nice if landing gear drop and hydraulic/pneumatic system failures were modeled in the game.[/QUOTE]

I've enjoyed this discussion, although we all need a beer to arrive at the correct answer! As for droopy underage or flaps, I will be happy when patch 4.11 arrives. Now my request to DT: DON'T LISTEN TO THEM - LISTEN TO ME!

[Tempest123]

Were the MiG-3 and Yak-3 from Aviaskins submitted to DT for inclusion, where they acceptable? just wondering.