Kingwood
08/29/05 07:55 PM
84.56.227.247
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I was just browsing through the Tactical Handbook again and read about the mechanical jump jets. Are they good for anything? Since they take 20% at Lvl 1 and 30% at Lvl 3 of the total mech tonnage, they seem to have no single advantage compared to normal jump jets. Would be nice if someone could find a use for them.
Cheers
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Toontje
08/30/05 08:02 AM
131.155.87.150
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Jumping from the water to the shore. (JJs don't work when submerged.)
Other than that, nope. Stuff from the tactical cheeebook is either useless (Acid warheads) or totally lethal (MPW LRM's 0-30 heat in 10 seconds, TSM+mace for what, 80 in a single location from an assault?).
Rather to blow up, then.
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Cray
08/30/05 08:10 AM
147.160.136.10
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I think mechanical jump jets get a better treatment in MaxTech. IIRC, they give 1 Jump MP per 5% of the mech weight. You can't change facing as with normal jump jets, but you're also not limited to walking speed for your jumping MP and (as Toontje said) you can use the mechanical jump boosters underwater.
(Note: Some rule interpretations of the MPWs only has them delivering a flat, non-cumulative heat load, like Infernos, so you won't get more than a few points of heat from them.)
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Kingwood
08/30/05 01:00 PM
84.56.210.248
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Wait... so you´re saying my 100 ton assault could jump 20 hexes??
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Wraith
08/30/05 10:46 PM
24.255.140.173
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For one there's other weights involved in mech construction. For another, IIRC, mechanical JJ still give you jump MP up to your standard walk speed.
-Wraith
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Cray
08/31/05 08:11 AM
147.160.136.10
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Quote:
Wait... so you´re saying my 100 ton assault could jump 20 hexes??
If you found some way to make the armor, internal structure, cockpit, and gyroscope total up to 0 tons, then yes.
Within the rules, you're looking at a jumping distance of about 10 with little room for weaponry - an L3 version of the Charger.
Practically speaking, you're probably better off using normal jump jets. A 100-ton mech can get a jumping distance of 3 for 6 tons from normal jump jets, while it can get a jumping distance of 1 for 5 tons from mechanical jump boosters.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Kingwood
08/31/05 08:28 AM
84.56.241.213
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Oh, heh, thought you meant JJs would give you 1 MP for every 5% of total mech tonnage, while using up 30% of total mech tonnage in weight.
Just imagine an assault loaded up with Pulse weapons jumping 20 hexes..
Mechanical jump boosters seem to be pretty useless, then. Thanks for clearing that up.
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Gnome76
09/01/05 12:06 PM
68.13.227.28
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Another thing would be that 'Mechs with non-fusion engines can't use standard jump jets.
Although what UtilityMechs need jumping ability?
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Cray
09/02/05 07:59 AM
147.160.136.10
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Quote:
Although what UtilityMechs need jumping ability?
Off the top of my head...
*Forestry Mechs operating without logging roads.
*Search and Rescue Mechs.
*Wilderness Fire Fighting Mechs.
Legs are a great addition to rough-terrain utility vehicles, but there are some terrain features that demand even more maneuverability.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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davion76
09/02/05 12:12 PM
12.219.244.44
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I had a thought on what could make the mechanical jump jets kinda interesting. The internal structure on the legs is now: standard * (1 + [#MJJs/4] ). So a mech w/ 4/6/4 (MJJ's) now has double the internal structure in the legs. This could explain why MJJ's weigh SO much. Mechs w/ MJJs require a much stronger leg, as they don't use jets of superheated air to slow down before impact.
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NewPharoah_Max
02/13/07 01:46 PM
207.160.205.13
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Toontje, what's wrong with having utility structure to make that 80 points of damage to be 160? Oh wait let me guess, engine explosions – I wouldn't want my 100 ton LAM to be in their effect radii. And Cray, it's absurd to think that a 'MechPilot using mechanical jump boosters to jump his/her 'Mech can't use its center of gravity to change its facing. I know it's very difficult but a +1 modifier per facing change could be applied to the landing piloting skill roll. Another option is to simply have the mechanical jump boosters latched carefully onto 'Mechfeet. Since 'Mechfeet apparently can handle the 'Mech's tonnage they should be capable of handling mechanical jump boosters and armor of the same tonnage, i.e., a 100 ton 'Mech's feet could handle 100 tons of mechanical jump boosters and armor strapped on so without armor 100 tons of mechanical jump boosters would provide a max jump MP of 10 (100 tons of 'Mech plus 100 tons of mechanical jump boosters equals 200 tons then multiplied by 5% equals ten 10 jump MP). Of course if the 'Mech is using utility structure then the 'Mechfeet could handle a mechanical jump boosters and armor tonnage double that standard structure 'Mechfeet could handle. so without armor 200 tons of mechanical jump boosters would provide a max jump MP of 15 (100 tons of 'Mech plus 200 tons of mechanical jump boosters equals 300 tons then multiplied by 5% equals max 15 jump MP).
Greetings to you too.
Edited by NewPharoah_Max (02/13/07 02:06 PM)
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Toontje
02/13/07 06:28 PM
88.159.70.51
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You were on your road to good boyhood, no need to become asinine.
Rather to blow up, then.
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Cray
02/13/07 08:17 PM
72.254.132.253
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Quote:
And Cray, it's absurd to think that a 'MechPilot using mechanical jump boosters to jump his/her 'Mech can't use its center of gravity to change its facing.
Absurd or not, them's the rules. Mechanical Jump Boosters do not allow facing changes.
And it wouldn't be the center of gravity, since that doesn't do anything. If anything changed the facing of a mech using mechanical jump boosters mid-flight, it'd be the gyroscope. Gyroscopes (well, their reaction wheels) are used in spacecraft today to reorient the spacecraft without thrusters.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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sdog
02/14/07 10:50 AM
139.174.165.124
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This would be only an attitude controll only, but the direction of the jump won't be changed, without aerodynamic or thrust vectoring devices.
did i read NP_M correctly he would like to have additional 100t mechanical jumpjets to strap below his mech's feet?
And also a 100t LAM with a 80 damage Cudgel?
maybe we all missinterpreted him, and should better toss him red herings...
I realised soon that the fun part of playing a military game is that we have lots of lifes and in the end knowone dies, ...
- Skaven, ArmA modding community
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Cray
02/15/07 04:07 PM
71.99.192.153
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Quote:
This would be only an attitude controll only, but the direction of the jump won't be changed, without aerodynamic or thrust vectoring devices.
Right, that's what I meant. You can't produce translational movement without reaction mass.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Karagin
02/15/07 07:20 PM
70.123.166.36
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Which would cost more weight or take up more space thus further limiting the unit correct?
Karagin
Given time and plenty of paper, a philosopher can prove anything.
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Cray
02/15/07 11:18 PM
68.200.109.191
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Quote:
Which would cost more weight or take up more space thus further limiting the unit correct?
Hmm. Complicated question.
It's true that, as you said, mechanical jump boosters would, by themselves, need additional weight and mass to steer and change their flight path.
However, traditional rocket-style jump jets can steer and adjust flight paths with less weight than mechanical jump boosters (big springs). Rockets are more weight-efficient motors than springs (vastly more weight efficient), and rocket-style jump jets use air as reaction mass (except in vacuum situations).
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Karagin
02/15/07 11:24 PM
70.123.166.36
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But isn't the reaction mass partial provided by the fusion recator? Or has that changed from the original fluff desciptions?
Karagin
Given time and plenty of paper, a philosopher can prove anything.
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Cray
02/15/07 11:49 PM
68.200.109.191
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Quote:
But isn't the reaction mass partial provided by the fusion recator?
Nope. A 400-rated reactor has maybe a milligram of plasma. That's not enough to lift a battlemech off the ground.
Quote:
Or has that changed from the original fluff desciptions?
The original fluff descriptions, c1986 Gray Death Legion novel era, tried to run jump jets on tanks of mercury. Fusion engines don't run on mercury, and fusion engines don't leak mercury when 'mechs take internal damage to legs, so the fusion reactor didn't provide the reaction mass.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Toontje
02/16/07 10:08 AM
131.155.85.19
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Always thought it ran like a simple jet engine, with energy supplied from reactor heating air.. Maybe pulsating, like the old ones... And Hg in vacuum, thus only 2x jump total jump availlable.
Rather to blow up, then.
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Cray
02/16/07 11:04 AM
147.160.136.10
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Quote:
Always thought it ran like a simple jet engine, with energy supplied from reactor heating air..
Yes. And novel and TRO descriptions to that effect led to the standardized description in the CBT:Companion, which is pretty much a jet engine that trades a kerosene combustion unit for a fusion-electric system (similar to flamers and aerospace fighter motors in that regard).
Quote:
And Hg in vacuum, thus only 2x jump total jump availlable.
Mercury is a rare reaction mass choice found in some older 'mechs. Generally, battlemech jumpjets in a vacuum will use hydrogen like aerospace fighters and other BT spacecraft. It standardizes logistics on a number of counts.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
Edited by Cray (02/16/07 11:05 AM)
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NewPharoah_Max
02/16/07 11:55 AM
207.160.205.13
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Quote:
Absurd or not, them's the rules. Mechanical Jump Boosters do not allow facing changes.
And it wouldn't be the center of gravity, since that doesn't do anything. If anything changed the facing of a mech using mechanical jump boosters mid-flight, it'd be the gyroscope. Gyroscopes (well, their reaction wheels) are used in spacecraft today to reorient the spacecraft without thrusters.
It's true that, as you said, mechanical jump boosters would, by themselves, need additional weight and mass to steer and change their flight path.
You mean like a bopdrive? It's also absurd that Maximum Tech prohibits jump jets and mechanical jump boosters from being used simultaneously.
Greetings to you too.
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Cray
02/16/07 01:57 PM
147.160.136.10
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Quote:
Quote:
Absurd or not, them's the rules. Mechanical Jump Boosters do not allow facing changes.
And it wouldn't be the center of gravity, since that doesn't do anything. If anything changed the facing of a mech using mechanical jump boosters mid-flight, it'd be the gyroscope. Gyroscopes (well, their reaction wheels) are used in spacecraft today to reorient the spacecraft without thrusters.
It's true that, as you said, mechanical jump boosters would, by themselves, need additional weight and mass to steer and change their flight path.
You mean like a bopdrive?
Yes, the bop drive is a violation of basic physics in that it achieves translation motion without reaction mass. That hasn't changed since I explained it to you in 1999 on rec.games.mecha.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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Toontje
02/16/07 02:10 PM
84.31.236.100
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hmmm. I remember that.
Holly Hopdrive you say?
Rather to blow up, then.
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Cray
02/16/07 02:47 PM
147.160.136.10
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Quote:
hmmm. I remember that.
Holly Hopdrive you say?
HeroChip misunderstood how the sock'em bopper toy worked, missing that it was pushing off solid objects to produce translational motion or just rotating around its center of mass on its own.
Mike Miller, Materials Engineer
Disclaimer: Anything stated in this post is unofficial and non-canon unless directly quoted from a published book. Random internet musings of a BattleTech writer are not canon.
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KamikazeJohnson
02/16/07 05:00 PM
207.161.35.90
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Quote:
It's also absurd that Maximum Tech prohibits jump jets and mechanical jump boosters from being used simultaneously.
It's a timing thing. 
Actually, according to some of the early source material re: Jump Jets, "The firing of the jets, liftoff, and landing take much longer than the actual time spent in the air." I would assume from that say 6-8 seconds spent preparing for or recovering from the jump, and only 2-4 seconds of flight. It could be tricky to trigger the jets to provide thrust during the short period the 'Mech is in the air after the MJJs are engaged...the pilot would probably need to trigger tghe standard jets FIRST, then time the MJJs to launch at just the right time to combine the lift...could be tricky.
Not to mention how firing jump jets in the middle of a mechanically-assisted jump would affect attitude control...
I'd expect at least a piloting roll to check that the timing was pulled off properly, and an additional roll for vector/facing control and a safe landing. Massive falling damage should you fail those rolls.
Peace is that glorious moment in history when everyone stands around reloading.
--Thomas Jefferson
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Askhati
02/22/07 03:55 AM
155.232.128.10
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What is this about the mechanical jets producing heat even when not in use? How is that suppose to be explained?
Evolve or DIE!
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Toontje
02/22/07 07:18 AM
131.155.85.19
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TSM works heated; boosters use TSM for jump power => required at elevated T, and this leaks out..
Rather to blow up, then.
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Tripod
06/19/07 04:34 AM
192.94.94.105
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on the note of not changing facing with MJJs...
i see no reason that an olimpic longjumper could not do a 180 degree spin before landing in the sand trap... but i dont see him remaining standing after touching the ground. to land sideways would be even more dificult.
i can understand not changing facing...
TBA
Edited by Tripod (06/19/07 04:36 AM)
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OgreMagi
08/28/07 10:15 AM
69.2.76.201
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I remember a mech that was designed for the solaris arena that had a 1/2/8 using a mech mace, its and interseting idea. a 8 jump gives ya a huge to hit modifyer and the base for physical attacks is better than most mechwarriors piloting skill.
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