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View Full Version : take off is a tricky thing after all...



argnan
03-06-2005, 12:21 PM
When i try to take off i can't hold the plane to a straight line... What's wrong about that??? Is there anything i can do???

BuzZz_WG
03-06-2005, 12:39 PM
That's because of the torque. The air is being pushed against your aircraft because of the big propellor you have in front of you. Compensate with rudder to keep it straight.

VW-IceFire
03-06-2005, 12:43 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by argnan:
When i try to take off i can't hold the plane to a straight line... What's wrong about that??? Is there anything i can do??? <HR></BLOCKQUOTE>Thats just engine torque. Use the rudder to counter it.

Bearcat99
03-06-2005, 07:55 PM
Practice till you get it right.... Set up a DF server offline or go into a QM with no bogies and do touch and gos till you get it right. Like the above posters said.. counter with the rudder.. but practice.

Hendley
03-06-2005, 09:11 PM
Some planes are harder than others, too. The I-153, for example, is particularly tricky. Trying a different plane might help...

Tully__
03-07-2005, 12:19 AM
Please please please!!!!

It is NOT torque, it is propwash. Torque causes roll, not yaw.

Flakenstien
03-07-2005, 12:45 AM
P-Factor is an aerodynamic effect that causes propellor-driven planes to yaw when they are flown at high power and low speed (takeoff and climbout, for example.)

At low speeds, the plane flies at a substantial angle of attack, and so the airflow is not parallel to the plane's axis. Relative to the plane, the airflow is directed several degrees upwards. Now the prop axis is normally parallel to the plane's axis. As the prop rotates, on one side the blades are travelling upwards and on the other side they are travelling downwards. (On most planes, the prop turns clockwise, as seen from behind, so the left side goes up and the right side goes down.)

The upwards angle of the airflow causes the downward (right) side of the prop to have a greater airspeed and angle of attack than the upward (left) side. So the downward (right) side of the prop generates more thrust. Pull harder on the right side of the plane than on the left and the plane will yaw to the left.

This is one of the reasons why most real prop planes need a certain amount of right rudder to keep them straight during takeoff and climbout.

The other factor that requires right rudder on takeoff (in planes with clockwise props) is spiral propwash. The sideways component of the spiral propwash strikes the vertical stabilizer from the left (in conventional single engine configurations), also causing a yaw to the left. In general, the spiral propwash effect is a lot stronger than P-factor.

You also need right aileron to keep the plane straight to counteract the rotational torque from the engine(s).

you also need to consider crosswind http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

RocketDog
03-07-2005, 12:58 AM
It's also because ground handling is very poorly modelled in IL-2.

Try taking a B-239 or I-16 up from a grass strip to see what I mean. I very much doubt that in real life an aircraft moving over a smooth grass strip would lurch from side to side the way they do in IL-2. Certainly, when I have seen WWII aircraft flying from the grass strip at Old Warden it all looks very smooth. Nothing like the comedy bouncing and lurching we get, particularly in the roll axis.

Overall, I think the torque effects are undermodelled (because I have read accounts of Wildcats needing full rudder to get off a carrier and aircraft don't seem to need rudders much in IL-2), but the ground bumpiness is stupidly overmodelled (because real aircraft don't tip from side to side like drunks on grass strips).

Regards,

RocketDog.

ColoradoBBQ
03-07-2005, 08:51 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by RocketDog:
It's also because ground handling is very poorly modelled in IL-2.

Try taking a B-239 or I-16 up from a grass strip to see what I mean. I very much doubt that in real life an aircraft moving over a smooth grass strip would lurch from side to side the way they do in IL-2. Certainly, when I have seen WWII aircraft flying from the grass strip at Old Warden it all looks very smooth. Nothing like the comedy bouncing and lurching we get, particularly in the roll axis. <HR></BLOCKQUOTE>

Because these pilots took off of those grass runways numerous times and knew how to compensate.

Atomic_Marten
03-07-2005, 09:41 AM
Hm. after some time you'll see that landing is the hardest part (some ac have hard time losing energy like FW190 and is somewhat harder to land than for example Bf109 although Messer have fragile undercarriage you must watch out for that first or second touch down bounce) but..

other than that; use minimal throttle (30-40%) and brakes to get on main taxi runway line up just nice and begin to accelerate using rudder to correct heading. You will be just fine.

Atomic_Marten
03-07-2005, 09:44 AM
quote:Originally posted by RocketDog:
It's also because ground handling is very poorly modelled in IL-2.

Try taking a B-239 or I-16..

I don't know about I16, but when I try to land B239, I know that I gotta be extra carefull due to his nasty landing behaviour http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif.(IMO one of the hardest planes to land).

RocketDog
03-07-2005, 09:51 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ColoradoBBQ:
Because these pilots took off of those grass runways numerous times and knew how to compensate. <HR></BLOCKQUOTE>

In IL-2 there's nothing you can do to prevent the wings from rocking from side to side on some aircraft on takeoff. But it's not because the real pilots know what to do and we don't. It's because their ground handling wasn't programmed as part of a game.

Regards,

RocketDog.

mortoma
03-07-2005, 02:22 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Hendley:
Some planes are harder than others, too. The I-153, for example, is particularly tricky. Trying a different plane might help... <HR></BLOCKQUOTE>You think the I-153 is tricky?...Have you tried the P-11C lately??? Very strange since it barely has enough power to climb but yet it has "monsta" torque during take off!!! Really is a contradiction of an FM if I ever encountered one.

mortoma
03-07-2005, 02:35 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by RocketDog:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ColoradoBBQ:
Because these pilots took off of those grass runways numerous times and knew how to compensate. <HR></BLOCKQUOTE>

In IL-2 there's nothing you can do to prevent the wings from rocking from side to side on some aircraft on takeoff. But it's not because the real pilots know what to do and we don't. It's because their ground handling wasn't programmed as part of a game.

Regards,

RocketDog. <HR></BLOCKQUOTE>Yes there is something you can do!! To eliminate the side to side rocking, takeoff on certain maps!! For example, if you try to take off in a P-40C in any of the PF maps and some of the older maps, like Kuban for example, you will rock your wings badly. But try that same plane in the Finland/Leningrad map and it won't rock at all!! It's a map related thing.
Also in the maps where you get the rocking motion, you'll not only get them on grass runways, but also hard runways to boot. But in the maps where the rocking motion is not there, you can even take off on grass with no trouble. I used to know which maps where non-rockers and which ones weren't but I forgot now. But I do remember Finland map is free of the rocking.

mortoma
03-07-2005, 02:40 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ColoradoBBQ:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by RocketDog:
It's also because ground handling is very poorly modelled in IL-2.

Try taking a B-239 or I-16 up from a grass strip to see what I mean. I very much doubt that in real life an aircraft moving over a smooth grass strip would lurch from side to side the way they do in IL-2. Certainly, when I have seen WWII aircraft flying from the grass strip at Old Warden it all looks very smooth. Nothing like the comedy bouncing and lurching we get, particularly in the roll axis. <HR></BLOCKQUOTE>

Because these pilots took off of those grass runways numerous times and knew how to compensate. <HR></BLOCKQUOTE>The behavior we see in some of the maps and some of the planes as far as the severe rocking motion is hardly realistic and pilots rarely encounter such nonsense. I have many hours in GA planes both tricycle gear and tail draggers on grass runways. The airport I flew out of for years near Kokomo Indiana ( 8I3 Glenndale ) was grass and it was/is always bumpy. But no aircraft I ever flew from there ever rocked from side to side. Especially to the ludicrous level we experience in this sim ( on certain maps in certain planes ). In many instances, the rocking is so bad it's hard to keep your wings from touching the ground. Not very realistic at all.

HvyPetals
03-07-2005, 04:59 PM
i find that in taking off on the p40 it helps to push the nose forward to keep the tail wheel off the ground as much as possible to keep from rocking.

once i had the sweet cherriest touchdown in the p40 - like butter perfection. i put the tail wheel down after gliding right up to the parking area on the main gear only. ahh the glory days. but there was no rocking until the tail hit. it was still rocking even after i killed the engine - like some west coast gin n juice caddillac