The other Zell; ZEro-Length-Launch What do you think?

[beachhead1985]

How might such a system be modeled under the current rules?

Basically what we're talking about here is an item of SupVee Equipment which consists of a set of disposable solid-fuel booster rockets which are strapped to an ASF or conventional fighter and used with a sufficiently muscular Transporter-Erector-Launcher. This would allow a unit to be literally rocketed up to a given (high) or even extra-orbital altitude as well as high velocity in order to defend against/intercept rapidly approaching hostile units.

Maybe you would even want these for space-based carrier units?

Thoughts?

References

https://en.wikipedia.org/wiki/Zero-length_launch
https://www.youtube.com/watch?v=wDstVGAmI74

[Daryk]

You mean aside from the rules that allow vertical take off?  ???

[beachhead1985]

You mean aside from the rules that allow vertical take off?  ???

Oh, but that is *slow*; or else at the limited speeds of the basic unit. I'm talking about something to even the odds against hostile ASF descending from space for beleaguered defensive fighters starting from Altitude 0 or less.

[Daryk]

Ah, so a launch with a "starting" speed above normal... right?

[The_Caveman]

It would look something like BattleMech detachable jump packs taking up bomb slots. Say, one bomb slot per point of starting velocity for each 20 tons of aircraft, round up. So to launch a MechBuster at velocity 2, you'd need to fill 6 bomb slots, which are instantly expended when the rockets fire.

The TEL vehicle would just need a Lift Hoist capable of carrying the aircraft.

There should be a mandatory control roll with a penalty, say +1 for each point of added velocity.

In theory, you could take off normally and fire the JATO pods in midair for an emergency speed boost...

[Daryk]

That sounds workable...

[beachhead1985]

How much thrust would we need to start putting serious altitude bars behind us?

This is fine for the 1950s version, but what we really need here is something almost akin to NASA Solid Rocket boosters in order to get grounded Aero units up to a high enough altitude to errode some of the advantage of an invading force. How much power would we need for that?

[The_Caveman]

Ground to space on the high-altitude map is, what, 6 hexes? You need 2 thrust to take off and an atmosphere hex costs 2 velocity to travel through, so anything with 14 thrust can reach orbit* on the first turn.

Unless you're going to strap a second fusion engine to your fighter though, don't expect a vast improvement in performance from SRBs. If solid rockets were all that, they'd already be using them.

*Under AeroTech's cartoon-physics definition of "orbit". Real orbits would demand a velocity of about 30 or more, but good luck keeping that all on one mapsheet.

[beachhead1985]

Ground to space on the high-altitude map is, what, 6 hexes? You need 2 thrust to take off and an atmosphere hex costs 2 velocity to travel through, so anything with 14 thrust can reach orbit* on the first turn.

Unless you're going to strap a second fusion engine to your fighter though, don't expect a vast improvement in performance from SRBs. If solid rockets were all that, they'd already be using them.

*Under AeroTech's cartoon-physics definition of "orbit". Real orbits would demand a velocity of about 30 or more, but good luck keeping that all on one mapsheet.

Okay, well lots of lighter ASK can do that already; what if I want a system that will give me that in a 100 ton Stuka? Or a lighter ASF/CF loaded with things like Air-to-Air Arrows/Rocket Pods.

There's really no need for this tech with fusion torch ships that can take off and land vertically (at least under certain restrictions) if all we want is the literal BT version of 1950s ZeLL.

*Soft SF for the WIN!!!!!

[SCC]

I think this is a very good way to kill your pilots.

[The_Caveman]

If you're dead-set on using chemical rockets to get a fighter into space, you could always stick your Stuka on top of a Saturn V.

But if you do, you're contractually obligated to play Steppenwolf when you light the fireworks.

[DaveMac]

How might such a system be modeled under the current rules?

Basically what we're talking about here is an item of SupVee Equipment which consists of a set of disposable solid-fuel booster rockets which are strapped to an ASF or conventional fighter and used with a sufficiently muscular Transporter-Erector-Launcher. This would allow a unit to be literally rocketed up to a given (high) or even extra-orbital altitude as well as high velocity in order to defend against/intercept rapidly approaching hostile units.

Maybe you would even want these for space-based carrier units?

Thoughts?

References

https://en.wikipedia.org/wiki/Zero-length_launch
https://www.youtube.com/watch?v=wDstVGAmI74

Impressive ;-)

https://theaviationist.com/2018/01/12/that-time-the-luftwaffe-experimented-with-a-rocket-launched-f-104g-starfighter/

[cray]

I'm not sure about conventional fighters, but aerospace fighters have multiple-G accelerations that make any 20th Century JATO or zero-length launch look snail-like by comparison. To get a faster takeoff than a vertical, Harrier-like ascent, such aerospace fighters would only need to be pointed into the air.

Rather than equipping the fighter with a rocket pack of some sort, perhaps a building / hex feature with "launch rail" might be adequate. Even a Stuka could lumber skyward at 4Gs - higher acceleration than most 20th Century manned rockets, let alone conventional fighters.

[HobbesHurlbut]

I'm not sure about conventional fighters, but aerospace fighters have multiple-G accelerations that make any 20th Century JATO or zero-length launch look snail-like by comparison. To get a faster takeoff than a vertical, Harrier-like ascent, such aerospace fighters would only need to be pointed into the air.

Rather than equipping the fighter with a rocket pack of some sort, perhaps a building / hex feature with "launch rail" might be adequate. Even a Stuka could lumber skyward at 4Gs - higher acceleration than most 20th Century manned rockets, let alone conventional fighters.

SOmething like what was done for Natter http://www.hyperscale.com/2015/reviews/kits/p7hg_img_82/fullsize/02_fs.jpg

[snewsom2997]

Makes me want to construct a Land Train with Launch Cars. Like the old F-86 and F-100 prototypes.

[beachhead1985]

I'm not sure about conventional fighters, but aerospace fighters have multiple-G accelerations that make any 20th Century JATO or zero-length launch look snail-like by comparison. To get a faster takeoff than a vertical, Harrier-like ascent, such aerospace fighters would only need to be pointed into the air.

Rather than equipping the fighter with a rocket pack of some sort, perhaps a building / hex feature with "launch rail" might be adequate. Even a Stuka could lumber skyward at 4Gs - higher acceleration than most 20th Century manned rockets, let alone conventional fighters.

But is that enough to be competitive against Aero assets incoming from a pirate point?

Makes me want to construct a Land Train with Launch Cars. Like the old F-86 and F-100 prototypes.

BattleTech meets AmTrak Wars!

[RifleMech]

I've toyed with jump jets acting as JATOS for shortening take off lengths. They might be good for zero length take offs for small aircraft. For larger aircraft I can see something like a mechs jump pack being used for zero length takeoff.

I would think their application would be limited to non VTOL/VSTAL aircraft to allow them to off from short runways or no runways. I can also see them being used by aircraft with limited fuel supplies.

Makes me want to construct a Land Train with Launch Cars. Like the old F-86 and F-100 prototypes.

How about a tug and barges used as launch pads.
.

[VhenRa]

But is that enough to be competitive against Aero assets incoming from a pirate point?

Considering you have like 3-4 hours warning... yes.

Like... a pirate point is hours of transit time for a dropship.

[beachhead1985]

I've toyed with jump jets acting as JATOS for shortening take off lengths. They might be good for zero length take offs for small aircraft. For larger aircraft I can see something like a mechs jump pack being used for zero length takeoff.

I would think their application would be limited to non VTOL/VSTAL aircraft to allow them to off from short runways or no runways. I can also see them being used by aircraft with limited fuel supplies.
.

That's how I got on this one; trying to figure out of I could make a FAST pack as in Macross work.

[RifleMech]

That's how I got on this one; trying to figure out of I could make a FAST pack as in Macross work.

Either system would work.

[beachhead1985]

Considering you have like 3-4 hours warning... yes.

Like... a pirate point is hours of transit time for a dropship.

Wait; so is a real orbital surprise attack in BT basically impossible then?

Reading the fluff I had the image of Pirate Point to hot-dropping mechs in less than an hour, vs; days and weeks.

[Daryk]

A one hour jump to drop would either require hitting something well beyond the habitable zone, or some VERY specific orbital mechanics and high thrust.

[The_Caveman]

A one-hour transit time by DropShip at 1g would require you to arrive just tens of thousands of kilometers from the planet. Like not even a quarter of the way between Earth and the Moon. The Earth-Sun L1 point is about 10x farther from the planet.

If you burned at 3G you could get from the Earth-Sun L1 point to the planet in about 130 minutes with a mid-point turnaround. Aerobraking will let you shave all of about 20 minutes (make the midpoint turnaround 58% of the way there and hit the atmosphere at 35 km/s--and hope your course calculations are accurate or you'll be lithobraking instead!). If BT spacecraft can survive reentry at 50 km/s, you can do the turnaround 71% of the way there and arrive in an hour and 41 minutes.

Even with extreme aerobraking, doing the transit in under an hour would require 9G+ of acceleration. The fastest DropShips in existence, doing 6G, could only do it in 78 minutes and the crew (and possibly the hull) would be in rough shape after more than an hour at 6G.

I'm not sure that an orbital configuration is possible that would get you to low orbit in less than an hour at safe accelerations. Maybe the moon of a gas giant could have an L1 point close enough but it would be extremely unstable unless it was the only moon of any size.

[VhenRa]

Wait; so is a real orbital surprise attack in BT basically impossible then?

Reading the fluff I had the image of Pirate Point to hot-dropping mechs in less than an hour, vs; days and weeks.

Pretty much, yes. You're honestly better off coming in at the standard point and flying in system pretending to be the monthly supply convoy/free trader/etc etc, using civilian codes.

[Daryk]

A very dim star with a large planet might make it possible, but "habitable" wouldn't really be "earth-like" in any way.

[beachhead1985]

Hm. Not good.

Now I am in the real 1950s US Military position of trying to find a use/role for this cool idea I came up with.

Would there be tactical advantages for a first turn speed-boost on takeoff?

[Daryk]

How many near-zero warning attacks do you expect?  The "pretending to be civilian traffic" trick might be prevalent enough to warrant it, or the world's government might just be that paranoid.

[The_Caveman]

Being able to dispersal-base your fighters on trucks in preparation for an invasion is still a good idea. Fixed air force bases are WMD magnets.

[RifleMech]

I can see these systems coming and going in terms of popularity. ZEL be more popular when WMDs are in use or there's already an invasion force on the planet as you can't kill what you can't find. JATOs can be used anytime you need to take off from a short runway but I think again more popular on worlds that see a lot of raids and/or invasions. The faster you can get your fighter in the air the sooner they can intercept the enemy. They'd also have a bit more flight time so intercepters can hang around a bit more until air superiority fighters show up.

[Jellico]

Being able to dispersal-base your fighters on trucks in preparation for an invasion is still a good idea. Fixed air force bases are WMD magnets.

That's nice for a week. Then the maintenance techs go on strike.

And you are still facing the issue that standard ASF have VTOL and can pull dangerous Gs from a standing start without assistance.