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View Full Version : Omitted aircraft quirks and details



PlaneEater
07-26-2005, 01:59 PM
While I realize IL-2 is more or less a generalized overview of most aircraft, there's a few characteristics and quirks unique to certain aircraft that I think would benefit the sim by being added.

--100% throttle on the ground when standing still flipped planes over. Bf-109s, P-51s, Fw-190s, Corsairs, Spitfires, Hurricanes--all had warnings not to suddenly throw the throttle all the way open when standing still. The torque would either flip or roll the plane over, or tear the engine off its mounts. Basically all of the high-horsepower single engine aircraft did this (maybe not the P.llc). This would also go a LONG ways towards stopping those nitwits that spawn and instantly firewall the engine, then take off straight across the runway. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

--The Bf-109's exceptional takeoff twitchyness isn't well represented and never has been. A small article posted recently here (wish I had the link) by a beta tester who had the opportunity to sit in a Buchon illustrates it well--he nearly totaled the plane when he opened 90% throttle during the takeoff roll, and got airborne with something close to 40 degrees of yaw.
The plane would swing left as the tail rose, requiring constant and precise rudder control. If you tried to raise the tail quickly, the swing was sudden and very hard to stop. Also, "It is advisable to let the airplane fly itself off since, if pulled off too soon, the left wing will not lift, and on applying aileron the wing lifts and falls again, with the ailerons snatching a little." (Farnborough evaluation by M.B. Morgan and R. Smelt)

--Rapid increase of right yaw in a dive with P-40s. The Warhawks were well known to increasingly swing their nose right as they picked up speed in a dive, and required more and more left rudder input to keep them straight.

--Compressibility in P-47s and P-51s. Both suffered from compressibility buffeting in high speed dives--not loss of control, buffeting. I don't believe this is modeled currently.

That, and I'd really like to see thin trails of exhaust smoke when sudden throttle changes are made or the throttle is opened fully. This was particularly ubiquous on the DB60X engined planes--many reports that Bf-109s were hit and trailing thick black smoke was actually the 109 pilot gunning the engine and diving away.



...just had to get it out of my system.

FritzGryphon
07-26-2005, 05:01 PM
torque would either flip or roll the plane over

When the the plane is stationary, torque will not flip it over. You'd probably not even be able to roll it off it's wheels. Please everyone stop saying that it does, it is simple physics.

Think about it. You'd need nearly the equivalent of the entire airplane weight in pure tortional force to get it over it's wing; not going to happen in a plane with much less than 1/5 T/W ratio (and most of that thrust is forward, not tortional, unless you were to feather the prop while doing this).

Some causes of upside down planes might be torque-induced snap rolls (in which case assymetric lift flips the plane not torque), or perhaps nosing over or dragging a wing on takeoff roll.

The tortional force is merely the trigger for the plane to flip in all these cases, not the thing providing the actual force.

BBB_Hyperion
07-26-2005, 05:15 PM
Well i know of some 190 incidents that flipped on its back by opening the throttle too fast . Seems that was a problem on all high hp planes.

FritzGryphon
07-26-2005, 05:35 PM
Oh, and I'd just love to see a pic of an engine ripped off the plane by torque. Never seen that before. http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif

If you throttle up really fast, the engine will rip off, and flip over.

I'm not trying to be annoying, just amused by 'torque fever' is all (especailly when people call slipstream and gryo effects 'torque'). I am becoming afraid my clothes dryer will flip over due to torque if I press the button too hard.

PlaneEater
07-26-2005, 06:27 PM
There is a very clear, very specific warning in the P-51 flight manual NEVER to exceed 40"/Hg when chocked to avoid flipping the plane over it's nose and onto it's back.

I don't think the USAAC would have put that in there just for fun, and I'm quite sure it wasn't a problem unique to the P-51. In fact, it was probably far worse with the P-40, Bf-109, and Spitfires due to the narrow undercarriage.

I know of at least 2 incidents of this happening with Fw-190s, so it doesn't seem to be prevented by wider gear, either--and that brings pretty much every other single engine fighter into the fold: P-47s, Yaks, LaGGs, Las, MiGs, Corsairs, Hellcats / Wildcats, Zeros, everything except, basically, the P-38, BI-1 & Me-163, and the He-162.

I've got a tape of ground handling mishaps and carrier deck accidents that has a few clips of this happening. It includes a short segment pulled from a training fill used in transitioning pilots to the AT-6 and advanced flight training. A test pilot, in a P-40 with a reinforced cockpit, shoves the throttle--from idle, standing still--all the way open. The poor Warhawk does what I can only describe as a shoulder roll: left wingtip drops, nose goes down, and over it goes.

Grey_Mouser67
07-26-2005, 06:51 PM
I'd add that the yaw effect throwing off gunnery is not modelled either...this would be most evident in nose mounted guns and why rudder input/trim was important...if your plane was yawing left, your guns shot left too. I think this is why Luftwaffe aces and soviets w/ nose mounted guns were so intent on getting so close while wing mounted guns were often sighted in at 500 meters.

Compressibility was also present and documented in the Fw series as well as Hellcats and corsairs. Bearcats were equipped with Dive brakes as were D-30 and up Jugs.

I also believe, particularly with the new flight model, there are inaccuracies in the more subtle and qualitative handling aspects of aircraft...some flew like they were on rails and they shake and shimmy like crazy and others that were inherently unstable are solid as a rock. In fact, i'll name a few planes, the Mustang, Jug and Lightning for example, are very unstable in the vertical plane about its center of gravity...pitch. These aircraft were known as solid, stable gun platforms. It is this instability that helps fuel the fires of the .50's are too weak. Imagine if a P-38 flew as solid and steady as a 109 in terms of gunnery....whew!!! and it has been much improved over the 3.04 days!

NonWonderDog
07-26-2005, 08:26 PM
Hmm? The guns shoot where the guns are pointed. The gunsight is aligned with the guns. Hence the guns shoot where the gunsight is pointed, no matter how much of a skew you might be in.

As far as I can tell the velocity of the plane is already added to the rounds when they fire, so everything that needs to be in the sim is already in. When you fire the waist guns on a bomber in the sim, the rounds travel along with your plane sideways, right? I think they even curve a bit away from your direction of travel becuase of air drag.

WWMaxGunz
07-26-2005, 10:43 PM
The guns do shoot where the sight is pointed but when you and the target are moving
at flight speeds the shots won't hit what you see in the gunsight if you flight is
not coordinated or the target is turning, unless the two cancel each other.

500 yard harmonization?
In the debate on 50 cal dispersion, the time to target and ability to hit a dodging
target was a major reason not to engage past I think 400 yards, about 360 meters.
But if my target was bombers then I'd shoot longer, sure.

WWMaxGunz
07-26-2005, 10:45 PM
BTW PlaneEater, given the number of sims that get these things right and model to the
levels of FB/PF you really do have to, uhhhhhhhhhh .........

NonWonderDog
07-27-2005, 12:54 AM
I don't understand what you're getting at. Say you're chasing a target that is flying straight and level. Now say you are a bit to the right of the target and flying in a 10 degree skid to the left with your gunsight on the target.

In this situation, you will fire your rounds at an angle of 10 degrees from your flight path. Your rounds will not travel in the same direction as you. However, if you and your target are moving at the same speed, you will still hit your target because your velocity vector is added to those of your rounds. It's like throwing a ball straight up into the air while walking; even though you've moved, it will still land on your head.

If you and your target are travelling at different speeds in this instance you will have to lead your target (either in front of or behind your target depending on relative closing rates). All flying uncoordinated does to aiming is make it more difficult to calculate lead. You have to take both angle-off *and* slip angle into account.

All of this occurs in the sim.

AerialTarget
07-27-2005, 01:42 AM
Originally posted by PlaneEater:
There is a very clear, very specific warning in the P-51 flight manual NEVER to exceed 40"/Hg when chocked to avoid flipping the plane over it's nose and onto it's back.

I don't think the USAAC would have put that in there just for fun, and I'm quite sure it wasn't a problem unique to the P-51. In fact, it was probably far worse with the P-40, Bf-109, and Spitfires due to the narrow undercarriage.

I know of at least 2 incidents of this happening with Fw-190s, so it doesn't seem to be prevented by wider gear, either

While I agree with your statements, for the most part, this part is wrong. Narrow undercarriage has nothing to do with a plane flipping on its pitch axis. For that matter, neither does torque (rather, gyroscopic effect, as Fritzgryphon pointed out). The reason a ship with a powerful engine will flip on its pitch axis when chocked is because the engine pulls the aircraft forward, but the wheels are immobile.

I think that what should be happening when you slam forward the throttle is the "shoulder roll" you described. But this is not from the gyroscopic effect of torque, it is from excessive power. And I don't think it should happen unless you are holding the ship with brakes (or chocks).

As for the roll caused by this action, I don't know much about it, but I am guessing that it should only be enough to drag a wingtip. Your description of the P-40 test seems to confirm this. One thing is sure - the game is wrong, as the only way you can possibly even dip a propeller is to hold brakes, apply full power, and wait several seconds.


Originally posted by PlaneEater:
I've got a tape of ground handling mishaps and carrier deck accidents that has a few clips of this happening. It includes a short segment pulled from a training fill used in transitioning pilots to the AT-6 and advanced flight training. A test pilot, in a P-40 with a reinforced cockpit, shoves the throttle--from idle, standing still--all the way open. The poor Warhawk does what I can only describe as a shoulder roll: left wingtip drops, nose goes down, and over it goes.

Where can I find this movie?