Project Bases to Land Planet Hopper Class star ships

[ex-orbinaut]

Yes, and this is exactly what I modeled. Instead of touching down with vertical speed only, have some remaining horizontal speed, which you did not yet neutralize.

You only hover above the pad, if you have too much fuel. Landing on a runway or on a VTOL pad makes no difference in that case, except that you can hover if you go for a vertical landing, while you can't hover for a horizontal landing.

Agreed. Energy cannot be destroyed, only converted.

Basically, I think we are on a matter of personal technique. I find it easier to "line up" with a centerline on an extended approach with some forward velocity than to stop on a dime in a hover; I tend to under or over shoot a bit when trying to stop dead on a point.

This approach technique works for me even in a no atmosphere world on Orbiter, using short bursts of translation RCS to fine tune the approach azimuth and slope. Then (as I do not have any runways on the Moon in my installation), I bring out the retros to stop, light the hovers, and you know the rest. I have run out of fuel at this point, I confess, which is why the runway did seem to be a reasonable idea to me, in agreement with Artlav's original proposal, as that critical fuel is saved.

Say it. "Go and practice those hovers some more!"

There is another consideration, too, that might knock the runway on the head. It would have to be aligned to a "nautral" inclination for its latitude, with respects to the orbit, or you end up wasting fuel anyway altering your orbital plane to coincide. As an orbit can cross the latitude at any angle (surprise, surprise!), there is no "natural" alignment. It would have to be a "swivel mounted" runway to align with YOUR plane, if it were to effect any fuel saving at all, and now we are getting really stupid...

Had fun with you guys today. Rare thing that I can spend so much time enjoying myself. Bye for now and thanks!!

 

[TCR_500]

I've added another runway to the Earth port. That completes the 4 runway, now to do the taxiway. Do I use mesh files for the taxiway?

 

[ThatGuy]

However, since there is no atmosphere, I'd be more concerned with overheating the breaks than locking them up. On Earth, the wheels cool themselves down, which helps with overheating.

Thremo dynamics aren't my best subject but I do believe that temperature change will occur in a vacuum, possibly faster than in the atmosphere.

 

[TCR_500]

Ok, let's not wonder too far off topic. To be honest, I would like to talk more about the behavior of heat, but that can wait.

One of the reasons I'm building the bases is, well, I was never very good at vertical landings. Vertical take-offs are fine, but when it comes to landing vertically, I usually only do one a few minutes after take off if I abort mission.

 

[Urwumpe]

And you think landing horizontally on the moon will be simpler?

 

[ThatGuy]

Ok, let's not wonder too far off topic. To be honest, I would like to talk more about the behavior of heat, but that can wait.

Right, sorry.

Landing horizontally on the moon would be much harder. Without an atmosphere, you can't easily make heading changes. You might waste more fuel lining up to the runway and landing horizontally than landing vertically

 

[TCR_500]

If you are lined up correctly when you come out of orbit, yes. However, I found it difficult to get one set up without going into orbit. If it helps any, I do have an ILS to help line up with the runway. Although, I found that the faster you are going, the harder it is to line up with the thrusters. But once you are lined up properly, just lower the craft, slow the vertical speed down, and land. But getting lined up is something you do while in orbit.

 

[Urwumpe]

Aha!

 

[TCR_500]

Well, the plan kind of backfired on me, but a one mile runway will give quite a challange. I might put the nose up a little to slow the ship down before I land. It might or might not save fuel over using the retro thrusters.

And I put the Surface Base Wizard on compatability mode for XP. It works perfectly now.

Ok, now let's see. Should I double the runway length for the Moon base? Or is one mile long enough.

 

[Urwumpe]

You will sure be able to calculate the needed length of the runway for slowing down.

 

[TCR_500]

Good point. Well, I think I'll do a majority vote on the length. The width is 300 feet (91.44 meters). That's for the Earth base runway too.

 

[Hielor]

If you are lined up correctly when you come out of orbit, yes. However, I found it difficult to get one set up without going into orbit. If it helps any, I do have an ILS to help line up with the runway. Although, I found that the faster you are going, the harder it is to line up with the thrusters. But once you are lined up properly, just lower the craft, slow the vertical speed down, and land. But getting lined up is something you do while in orbit.

A plane change of 60 degrees takes as much delta-V as it does to get to your existing velocity already. As has been noted already, the brakes will not be very effective, due to reduced weight and reduced ability to dissipate heat. I would bet that unless your orbit was already lined up within a few degrees of the runway, it would be more efficient to do a vertical landing than a horizontal landing.

Unless, of course, your runway is on a giant turntable, and can rotate to accept vessels from any direction.

 

[RisingFury]

Good point. Well, I think I'll do a majority vote on the length. The width is 300 feet (91.44 meters). That's for the Earth base runway too.

I know you're an American and were born into the imperial units... but Oribiter uses metric. The biggest advantage of metric system is that it's simple:
1 km = 1000 m
1 m = 1000 mm
1 mm = 1000 um (micrometers)

I know just trying to stop using imperial units and using metric isn't easy cos you need to get a feel for things, but I suggest this to you:

If you're building the base or something and want to go for a length of say... 300 feet, when you convert that into meters and get 91.something, why don't you make it 100 meters... That will still be roughly 300 feet... 310, actually... You'll quickly get a feel for metric.

---------- Post added at 11:34 PM ---------- Previous post was at 11:26 PM ----------

Also, the poll you set up will kinda get you nowhere. Here's why:

Options are:
1 km
1 mile = 1.6 (roughly) km
2 miles = 3.2 km
4 km

Isn't it easier to just say:
1 km
2 km
3 km
4 km
?



One more thing... for your ship to slow down faster, you can try increasing the friction coefficient.



Also, the reason why everyone's saying landing horizontally on the Moon / Mars is useless is because... you have to set up your orbit at exactly the right inclination... and have to de-orbit at the right time. If you come in at 4 km/s at even 10° angle... the runway is no good. Course corrections get VERY tougher, the faster you go. Just slowing down in the atmosphere and landing vertically is the best approach. But it does require some more skill.

One quick hint is to use the Level autopilot and the MapMFD to match your vertical acceleration so that your vertical velocity doesn't change (much). On Earth, that'll be 9.81, on the Moon it's like 1.6 or something, IIRC.

 

[Hielor]

I know just trying to stop using imperial units and using metric isn't easy cos you need to get a feel for things, but I suggest this to you:

If you're building the base or something and want to go for a length of say... 300 feet, when you convert that into meters and get 91.something, why don't you make it 100 meters... That will still be roughly 300 feet... 310, actually... You'll quickly get a feel for metric.

328

 

[TCR_500]

328.08 feet.

 

[Hielor]

328.08 feet.

While your ability to use a calculator is impressive, you miss the point.

 

[Nerull]

A plane change of 60 degrees takes as much delta-V as it does to get to your existing velocity already. As has been noted already, the brakes will not be very effective, due to reduced weight and reduced ability to dissipate heat. I would bet that unless your orbit was already lined up within a few degrees of the runway, it would be more efficient to do a vertical landing than a horizontal landing.

By a few orders of magnitude. An orbital plane change is just about the most expensive operation you can possibly perform. Trying to save fuel this way is like plugging a tiny crack while the rest of a dam has breached - you're wasting your time.

 

[TCR_500]

Well, I do have 6 landing pads on the base. Plus I'm going to put a bigger one for the Planet Hopper.

Can anyone answer my question about the taxiways? Do I use a mesh file, or something esle for them?

And I've already known that 100 m is 328.08 feet. Just stop trying to make me use the metric system and drop the imperial system. It won't work.

 

[garyw]

Have a look at the SDK as that talks about runway and taxi placement I believe.

You will HAVE to use metric. No getting away from it as that's what Orbiter uses internally.

 

[Urwumpe]

He could use imperial units in Orbiter. This would also make his spacecraft design a bit more realistic, because it will then be between DG and Shuttle in size :lol: