Author Topic: Aircraft mass (Read 1183 times)

Benny Moore · « **on:** February 17, 2007, 09:12:07 PM »

How is the aircraft mass handled in Aces High II? I know from the screenshots in the stall speed thread that lift and drag are intricately modelled, having many points being calculated in real time. Is mass done the same way? If so, is the weight evenly distributed along the points, or is the majority of it in the fuselage and less in the wingtips?

Shaky · « **Reply #1 on:** February 18, 2007, 12:03:30 AM »

Mass is distributed as it is in the "real" aircraft, including the mass of fuel and ordie.

Benny Moore · « **Reply #2 on:** February 18, 2007, 12:33:06 AM »

How do you know? And how did they manage it? I've thought about the best way to realistically model mass, and the only thing I could think of was to weigh individual aircraft parts to find their weight and center of balance. It sounds tricky. I'd like to know how Hitech dealt with this.

Bronk · « **Reply #3 on:** February 18, 2007, 12:41:43 AM »

Take 2 drop tanks and then drop one. Bet the plane pulls to the side with the tank.

Bronk

Benny Moore · « **Reply #4 on:** February 18, 2007, 01:29:17 AM »

It does. This could be just the drag, but it's probably weighted too. But how is it done? Obviously the drop tanks and bombs are fairly easy to know the weight of, but what about the different parts of the airplanes?

RAIDER14 · « **Reply #5 on:** February 18, 2007, 02:01:10 AM »

Quote

Originally posted by Benny Moore
It does. This could be just the drag, but it's probably weighted too. But how is it done? Obviously the drop tanks and bombs are fairly easy to know the weight of, but what about the different parts of the airplanes?

In bombers on a B17 if you shut off the #1 engine you will feel some drag and counter it by shuting off the #4 engine

Raptor · « **Reply #6 on:** February 18, 2007, 02:34:28 AM »

Manually select which fuel tanks you use using shift+f. I believe you can select right wing tank or left wing tank. See if that has any affect

Murdr · « **Reply #7 on:** February 18, 2007, 03:35:03 AM »

You are aware that weight telemetry can be viewed on the E6B?

They probably have a set dry weight CG for an aircraft, and everything expendable that's loaded on the plane affects the CG location proportional to its distance from the "dry" CG.

Everything added to the plane from the hanger affects CG as modeled. Find it hard to believe that anyone with a little AH experience would think otherwise, or need to "test" that.

From what Ive observed, "plane parts" only affect total weight if they had expendable materials on them (loaded pylon, internal fuel tank).

Quote

Originally posted by Raptor
Manually select which fuel tanks you use using shift+f. I believe you can select right wing tank or left wing tank. See if that has any affect

Heck yea it does. That's how to best land with a damaged wing. Move the CG over towards the good wing by draining any fuel tanks on the side of the bad wing.

kvuo75 · « **Reply #8 on:** February 18, 2007, 03:51:11 AM »

weight is not mass

squealer · « **Reply #9 on:** February 18, 2007, 04:42:20 AM »

Quote

Originally posted by kvuo75
weight is not mass

Since we all live at the surface of the earth where the acceleration of gravity is relatively constant, it has been natural for us to confuse the concepts of mass and weight. To study the difference, we need to separate these two "parameters." We could either leave the earth's gravitational field so that we would have no weight, or create an experimental situation where weight is not a factor. An easy way to do this is to use floating objects. Floating objects still have all their mass, and move almost friction-free in still water, but we don't notice their weight since the water supports (opposes) it. A small block of wood floating in water can be pushed back and forth very easily by hand. Pushing a large motorboat requires either a much greater push or a longer time to have the same effect. The effort required to change the motion of an object is a measure of its mass. The motorboat has a lot more mass than the block of wood.

The metric unit of mass is the kilogram. The kilogram was intended to be the mass of a cube of water one-tenth of a meter on a side. In actual practice the official standard of the kilogram is a cylindrical piece of platinum-iridium alloy kept in a secure location in France. A megagram (metric ton) is the mass of a cubic meter of water. A kilogram is about 2.2 pounds. A metric ton is about 2200 pounds.

The metric unit of weight (or any other force - such as that of a stretched spring, or a bat striking a ball, or a locomotive pulling a train) is called the newton. One newton is defined as the amount of force required to cause one kilogram to accelerate one meter per second every second. A newton is roughly the weight of four ounces, or a pound weighs about four newtons. A kilogram at the earth's surface has a weight of about 9.80 newtons. Above the earth's surface it weighs less and less. Below the earth's surface (in a mine or borehole) it also weighs less. Can you figure out why?

Don't believe a word.

LEADPIG · « **Reply #10 on:** February 18, 2007, 04:52:31 AM »

In engineering terms all weight and mass of an airplane will be measured through the center of gravity and center of pressure that is where all weight is measured and multiplied by the length on the lever arm from said point and the weight acting in that direction from the tip of the lever arm..........Mechanical Engineering Student Ledpig

Jaxxon · « **Reply #11 on:** February 18, 2007, 04:56:06 AM »

Woh

LEADPIG · « **Reply #12 on:** February 18, 2007, 04:57:23 AM »

Quote

Originally posted by squealer
Since we all live at the surface of the earth where the acceleration of gravity is relatively constant, it has been natural for us to confuse the concepts of mass and weight. To study the difference, we need to separate these two "parameters." We could either leave the earth's gravitational field so that we would have no weight, or create an experimental situation where weight is not a factor. An easy way to do this is to use floating objects. Floating objects still have all their mass, and move almost friction-free in still water, but we don't notice their weight since the water supports (opposes) it. A small block of wood floating in water can be pushed back and forth very easily by hand. Pushing a large motorboat requires either a much greater push or a longer time to have the same effect. The effort required to change the motion of an object is a measure of its mass. The motorboat has a lot more mass than the block of wood.

The metric unit of mass is the kilogram. The kilogram was intended to be the mass of a cube of water one-tenth of a meter on a side. In actual practice the official standard of the kilogram is a cylindrical piece of platinum-iridium alloy kept in a secure location in France. A megagram (metric ton) is the mass of a cubic meter of water. A kilogram is about 2.2 pounds. A metric ton is about 2200 pounds.

The metric unit of weight (or any other force - such as that of a stretched spring, or a bat striking a ball, or a locomotive pulling a train) is called the newton. One newton is defined as the amount of force required to cause one kilogram to accelerate one meter per second every second. A newton is roughly the weight of four ounces, or a pound weighs about four newtons. A kilogram at the earth's surface has a weight of about 9.80 newtons. Above the earth's surface it weighs less and less. Below the earth's surface (in a mine or borehole) it also weighs less. Can you figure out why?

Don't believe a word.

That is exactly true this was first proven by Galileo and demonstrated by astronauts on the moon. Objects of differing masses wil be accelerated the same amount by an equal force of gravity. (i.e. a bowling ball wiil hit the ground the same time as a feather without the interference of air resistance.

TimRas · « **Reply #13 on:** February 18, 2007, 08:37:41 AM »

Quote

Originally posted by Pyro
The moments of inertia are problematic since we only have this data on a few planes and had to use that to make estimates on all the others.

Old Sport · « **Reply #14 on:** February 18, 2007, 09:15:21 AM »

Quote

Originally posted by Pyro
The moments of inertia are problematic since we only have this data on a few planes and had to use that to make estimates on all the others.

I've wondered about the P-38 in particular. If you go into a hard roll and then go to neutral stick the roll stops immediately. Whereas I would suspect that due to the inertia of the 2 engines, turbos, main gear, booms and fuel that it would continue to roll, at least to some degree, until reverse aileron was provided. Maybe not, but a different sim does require some reverse aileron to stop rolling. Just curious.

Best regards.