Help me learn stuff about aircrafts and space shuttles

[Goth]

So what's "crossrange maneuvering"?

 

[Urwumpe]

So what's "crossrange maneuvering"?

Imagine a coordinate system, that you put on the surface of Earth, directly below a point in space called "Entry Interface" or EI. Three arrows, all perpendicular to each other.

The first arrow is the downrange, it points from EI in the direction of your orbit ground track, flat on the surface of Earth. The next arrow is crossrange: It is 90° away from the downrange and still on the surface. The third is altitude, simply as that.

So, cross range is in that coordinate system, how far you are lateral to your reference ground track.

Crossrange maneuvering describes the ability of a spacecraft to leave the downrange direction and travel crossrange during reentry. This is not unlimited, and defined by lift and drag of the spacecraft. capsules have a pretty low cross range generally, winged vehicles a bigger one. Also you can't fly in any direction because of thermal and dynamic pressure limitations (= dropping too fast into the denser atmosphere layers)

If you have "1500 km crossrange" available by your spacecraft, this means that you could land on a base, that is 1500 km away from your orbit ground track.

downrange and crossrange are also used for ascent of a spacecraft, and work in the same way. Downrange is not the orbit ground track then, but rather pointing on the great circle defined by your launch position and launch azimuth, the origin of the coordinate system is the launch pad.

 

[paddy2]

Nice one
I understood all that. Well written sir

 

[Goth]

Second question is: if the DG was real, how the TRIM (which in Orbiter you change with insert and delete keyboard keys) would be achieved?
And does this "feature" also exist in real aircrafts?

 

[RisingFury]

Second question is: if the DG was real, how the TRIM (which in Orbiter you change with insert and delete keyboard keys) would be achieved?
And does this "feature" also exist in real aircrafts?

Yes, this feature does exist in real life. It's done by offsetting the 0 position on the air control surfaces. The 0 position is where the control surface returns to when you let go of the controls.

Imagine if the plane pitches down on its own slightly. You can either keep holding the stick back to deflect the elevator up a bit, or you can just trim it to do that on its own.

Trim isn't only a real feature, it's vital for a good flight.

 

[Goth]

As I thought, but I didn't notice the ailerons moving. Now that you've confirmed how the trim works I've checked again more closely with both the stock DG and the DG IV and the ailerons are actually moving when changing the trim eheh. ^^

 

[boogabooga]

Yes, this feature does exist in real life. It's done by offsetting the 0 position on the air control surfaces. The 0 position is where the control surface returns to when you let go of the controls.

Or one can use "trim tabs" that are smaller than the full control surface.

 

[N_Molson]

Also notice that on most real aircrafts, you have trim on the 3-axis : pitch, yaw and roll. That way a well-set airplane can fly straight by calm weather, if you don't touch the throttle.

Trim is also very useful because fuel consumption change the plane's center of mass throughout the flight.

 

[Hielor]

Or one can use "trim tabs" that are smaller than the full control surface.

Which have the exact same effect of offsetting the "0" position of the controls

 

[RisingFury]

Also notice that on most real aircrafts, you have trim on the 3-axis : pitch, yaw and roll. That way a well-set airplane can fly straight by calm weather, if you don't touch the throttle.

Trim is also very useful because fuel consumption change the plane's center of mass throughout the flight.

On RC boats (nitro powered, large fuel tank), you actually have to trim the engine as well. As the fuel level in the tank drops and pressure increases, you have to close the needle that regulates the fuel flow into the engine when the carb is completely open.

 

[boogabooga]

No one said they didn't.

 

[n72.75]

Photo for reference: