Balloon

[Epicsauce]

Is it possible to make a 'balloon' that pulls up gently?

[Capt'n Skunky]

You know, that's a very good question and idea. I would think it's quite possible. Would be an engine with little to no weight, a ton of fuel and very low thrust.

Any modders care to take a stab at this one?

Cheers

Skunky

[Jack]

You could set the drag on the parachute to something negative, it would pull up.

[Epicsauce]

Spherical solid engine, 0 fuel consumption, 1 fuel, negative drag, 1 thrust.

[esd]

I did have this idea, but didn't think of the drag... I tried changing the mass to a negative - which didn't work; the game converted it back into a positive.

[Herra Tohtori]

Why not just model aerostatic lift? Adding air density by altitude function shouldn't be too complicated, and then you could just add a lift force vector for buoyant components.

[mekilljoydammit]

Well, HarvesteR did mention that it was on the slate at some point...

[Killerhurtz]

I have experimented on this (although my idea was not of a balloon, per se, but of an anti-gravity machine), and I have come to no advancements. As stated, negative mass did not cause any particular change, while negative friction had an unintended side effect. While it was utterly useless for providing lift above 35KM, it did have a few amusing and one potentially useful side effect. One of the side effect, the useful one, is that if you started going really horizontal, you would eventually accelerate to escape velocity, which means in theory if we could change drag mid-air (possibly with the help of the chute), we could make a device which would allow an easy 35KM orbit.

The other side effect, more amusing this one, is that while it DID slingshot you out of the planet, the reverse was also true. Which made the parachute obsolete - it made the ship accelerate towards the ground anyway.

Although now that I think of it, I might have a new part idea in the making. Anyone here excelling at making orbits?

[Corona688]

Haha, I tried making a ramjet with negative drag. It kind of worked but was incredibly unstable, the slightest deviation from vertical would produce a gigantic sideways reverse-drag sufficient to rip it right off. You could get several hundred mps below a thousand feet -- usually downwards, as it would accelerate you down as fast as you were going up even butt-first. If drag were a vector instead of a scalar, maybe...

[rastab0b]

nasa are working on a ballon/airship so its certanly a good idea.

[Epicsauce]

I'm thinking more Solar Sail. So like a parachute that uses the radiation pressure of the sun to travel.

[rastab0b]

thier planetry explorer http://gltrs.grc.nasa.gov/reports/2004/CR-2004-213345.pdf

[Corona688]

I'm thinking more Solar Sail. So like a parachute that uses the radiation pressure of the sun to travel.

Sure, if you want to run the game for decades or centuries.

[esd]

Sure, if you want to run the game for decades or centuries.

Depends on your route - slingshotting the sun can produce tremendous velocities, especially with a solar sail adding to the thrust. It is a very complicated maneuver though.

And why decades or centuries, if you're using time-compression (that they may introduce)?

[Thomas]

Done. kinda, it is horribly broken, since the chute wants to face downward while moving but something tries to flip it upright.

Feel free to edit this and try to make it work.

Also if anyone wants me to spend the time to make one that works, (by that I mean an engine) I can. But it seems kinda simple.

https://www.dropbox.com/s/9ihuq3scf2t1vda/testing.rar

[EvilLordMC]

Done. kinda, it is horribly broken, since the chute wants to face downward while moving but something tries to flip it upright.

Feel free to edit this and try to make it work.

Also if anyone wants me to spend the time to make one that works, (by that I mean an engine) I can. But it seems kinda simple.

https://www.dropbox.com/s/9ihuq3scf2t1vda/testing.rar

Wait,what?! A creeper balloon?!

Also,installed it,the game won't even load.'Loading...Loading...Loading...'

EDIT:Removed Naccele's parts,didn't work.Removed the balloon,the game still didn't work.Weird.

[Thomas]

Remove it if it won't work, but it is working fine for me, did you install anything else?

(edit) yep, still works. Also, I think when you set it's drag negative it increases forever, which is why they love to fly off, not just that they wobble out of control.

[Corona688]

Make sure that the folder you put in /parts isn't just a folder inside it with the rest of the part stuff. That's the only way I've managed to provoke infinite loading when installing working mods.

[DoctorEvo]

Hmm... using the engine module (either solid OR liquid) for this wouldn't do, as the engine only provides thrust in the direction it is pointed (which is not necessarily up). Using a modded parachute or other drag model wouldn't do either, as drag is velocity-dependent (for direction as well as magnitude).

Also, apparently setting a negative mass value doesn't create antigravity, so we can forget about that. :

Haha, I tried making a ramjet with negative drag. It kind of worked but was incredibly unstable, the slightest deviation from vertical would produce a gigantic sideways reverse-drag sufficient to rip it right off. You could get several hundred mps below a thousand feet -- usually downwards, as it would accelerate you down as fast as you were going up even butt-first. If drag were a vector instead of a scalar, maybe...

What an AWESOME idea!!

I see the problem with it producing thrust in the yaw direction though... that kinda sucks. I'm trying to think of a workaround...

I know that most parts have separate minimum and maximum drag parameters, which I presume are for forward flight and for sideways flight. Obviously, for a ramjet, we'd only want the FORWARD-FLIGHT value (i.e. minimum drag) to be negative. However, this alone is still not fully sufficient, as it would still cause a divergent situation at low AOA until the (presumably interpolated) drag value crossed the zero mark. To make up for this, I'd probably look into using the winglet module instead and adding some degree of lift to pull the net-force vector back to (or at least close to) the centerline of the rocket.

[Also, drag IS a vector. By definition, it is always in the direction opposite your direction of flight (which is NOT necessarily the direction you're pointed, mind you). The other component of total aerodynamic force is lift, which is - by definition - PERPENDICULAR to the direction of flight.]

[Corona688]

Also, drag IS a vector.

I think you know what I mean. Alter the direction or strength of the force by config file.

[DoctorEvo]

I think you know what I mean. Alter the direction or strength of the force by config file.

The values in the .cfg are LABELED as coefficients (well, in the winglets anyways), which makes sense, because there's naturally no way to dictate the velocity or dynamic pressure of a part through configuration. However, I'm not certain that they actually are coefficients, as that would mean that the program would have to dictate the characteristic area being used to determine the drag FROM this coefficient (and velocity and density and whatnot). This COULD be done via a simple calculation of frontal cross-sectional area, or an on-the-fly calculation of head-on area with respect to the direction of travel (doubtful), or more likely, this 'coefficient' is actually the 'drag area,' that is, the true drag coefficient TIMES the characteristic area. I still need to test for this; if this is indeed the case, the part developer would need to manually input higher drag values for larger parts of the same shape.

A little insight from the game devs would be wonderful right now...

[techtakular]

bump

[millsw]

in the night.