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Old 02-28-2007, 03:17 AM   #1
DataPacRat
 
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Join Date: Nov 2004
Location: Niagara, Canada
Default Getting underbelly skids to work

Finally broke down and bought GVB from e23, and am teaching myself how to use it.

For my first attempt, a "hoverboard" for a random sky-surfing superhero, late TL7 with TL16 megathrusters and power cell. Everything's all well and good, except for one detail. Since supers abuse their equipment in so many ways, and the hoverboard qualified for them, I threw in underbelly skids; and tried to get a Ground Performance profile... but something seems to be off with the specs, including a Speed Factor of -1.

According to my reading of Vehicles, the ground performance should look something like this:
Underbelly-skid Ground Performance: Speed Factor 6, Top Speed 405 mph, gAccel 55 mph/s, gDecel 5 mph/s, gMR 1.5, gSR 0, Ground Pressure 563 lbs./sf, Off Road Speed 0 mph.


... but the rough-draft design so far looks like this.

I'm probably going to throw out the stealth and cloak, saving 8 lbs.

Yes, even with TL16 power, the endurance sucks - but I figure that, once I figure out how to get GVB to show the stats for such, the thrusters will usually be run at around 10-20% of max thrust,

Yes, I know vehicles with harness crew stations aren't supposed to be streamlined... in this case, I had the /vehicle/ streamlined, and threw in an extra aDrag of 20 for the pilot, and it seems close enough to reasonable.

-----8<-----
TL7+16 hoverboard

Crew: 1 total. 1 crew station covering vehicle maneuvering system, communicator, navigation aid, 2 sensors.

Subassemblies: Vehicle +0, Body -2, Wings -4.

P&P: 500,000-kWs rechargeable power cell, 2,000 lbs. thrust mega thruster (vectored thrust; no access space).

Fuel:

Occ: harness Cargo:

Armor F RL B T U
Body 3/5 3/5 3/5 3/5 3/5
Wings 3/5 3/5 3/5 3/5 3/5

Equipment
All: 5.07 sf electrified surfaces; self-sealing hull; twomodest sound bafflings (-1 hearing modifier); modest stealth (-1 spotting modifier); modest infrared cloak (-1 spotting modifier); ram; 0.05 sf top deck. Body: computer navigation program (C2); datalink program (C1); emergency lights/sirens; GPS; short range radio communicator (3-mile range; scrambler); small robot brain (complexity 2, +0 DX; compact, genius); high security burglar alarm (Skill-20). Wings: LLTV (magnification x1); radar (scan 5, 0.1-mile range; low-res imaging); thermograph (scan 7, 0.25-mile range).

Statistics
Size: [LxWxH] 5x1x0.08 Payload: 200 lbs. Lwt.: 263 lbs.

Volume: 0.394 cf Maint.: 25 hours (3.85 mh/day) Price: $642,321

HT: 11 HP: 8 [Body], 4 each [Wings].
Aerial Performance, backswept wings: Stall Speed 0 mph, Drag 20.1, Top Speed 865 mph, aAccel 150 mph/s, aMR 9, aSR 3, aDecel 35 mph/s.

Aerial Performance, outswept wings: Stall Speed 0 mph, Drag 20.1, Top Speed 430 mph, aAccel 150 mph/s, aMR 10, aSR 3, aDecel 40 mph/s.

Underwater Performance: Drag 8, Top Speed 40 mph, uAccel 1,625 mph/s, uMR 0.75, uSR 4, uDecel (powered) 10 mph/s, ( 823 mph/s), Draft 0.97 ft, Test Depth 45 yds, Crush Depth 90 yds.

Underbelly-skid Ground Performance: Speed Factor -1, Top Speed -60 mph, gAccel 50 mph/s, gDecel 0 mph/s, gMR 0.25, gSR -2, Ground Pressure 563 lbs./sf, Off Road Speed 0 mph.

Surface-Water Performance: Drag 9, Top Speed 75 mph, wAccel 150 mph/s, wMR 0.75, wSR 4, wDecel (powered) 10 mph/s, ( 86.1 mph/s), Draft 0 yds, Flotation 19.2 lbs.

Space Performance: sAccel (unloaded) 7.61 G, ( 7.61 G), sDecel 7.61 G, sMR 7.61, sAccel 150 mph/s.


Design Notes:
TL7 heavy frame advanced materials [Vehicle].
TL7 DR 5 advanced composite [Vehicle].
Operating Duration: 1 H 23 M 17 S.
Vehicle Features: computerized controls, worn as a harness, radical streamlining.
Body: underbelly skid.
Wings: high agility, folding, auto-variable.
Volume: 0.308 cf [Body], 0.086 cf [Wings].
Area: 2.74 sf [Body], 2.33 sf [Wings].
Empty Space: 0.016 cf [Wings].
Aerial Performance, backswept wings: external item drag 20, payload 0, sweep back-swept,;
Aerial Performance, outswept wings: external item drag 20, payload 0, sweep out-swept,;
Underwater Performance: VXi crush depth;
Underbelly-skid Ground Performance:;
Space Performance: Payload 0;
----->8-----
__________________
Thank you for your time,
--
DataPacRat
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Old 03-01-2007, 09:56 AM   #2
tjoneslo
 
Join Date: Aug 2004
Location: Vermont
Default Re: Getting underbelly skids to work

The problem with the underbelly skids is a bug in GVB. To fix this do the following steps:

In the Performance Profiles repository, select the "Not Wheeled Ground Performace" template. Press Ctrl-F2 to edit the template. You will need to update three formula's in this template. Double click each of the profile formulas to bring up the edit forumla dialog. Delete all the text in the box, and replace it with the formula below:

Performance Profile formula 1 (Speed Factor): should be
IIF (vHas_Flexibody, 4,
IIF (vHAS_UNDERBELLY_SKID, 6,
Decode (vIndex_Ground_Type,
1 {Legs}, Decode (Range (vTOTAL_PROFILE_MOTIVE_ITEMS, 2, 4), 2, 8, 3, 10, 4, 12, 0),
2 {Skids}, 6,
4 {Tracks}, IIF (vTL <= 6, 10, 12),
5 {Half-tracks}, IIF (vTL <= 6, 12, 14),
6 {Ski-Tracks}, IIF (vTL <= 6, 8, 10), -1))) +
IIF(vHas_Improved_Suspension, 1, 0)

Performance Profile Formula 8 (gSR): should be
IIF (vHas_Flexibody, Select (vBody_Volume, 30, 3, 100, 3, 300, 4, 3000, 4, 4),
Decode (vIndex_Ground_Type,
1 {Legs}, Decode (Range (vTOTAL_PROFILE_MOTIVE_ITEMS, 2, 4),
2, Select (vBody_Volume, 30, 1, 100, 1, 300, 2, 3000, 2, 2),
3, Select (vBody_Volume, 30, 2, 100, 2, 300, 3, 3000, 3, 3),
4, Select (vBody_Volume, 30, 3, 100, 3, 300, 4, 3000, 4, 4), 0),
2 {Skids}, Select (vBody_Volume, 30, 2, 100, 3, 300, 3, 3000, 4, 4),
4 {Tracks}, Select (vBody_Volume, 30, 3, 100, 4, 300, 5, 3000, 6, 6),
5 {Half-tracks}, Select (vBody_Volume, 30, 3, 100, 4, 300, 4, 3000, 5, 5),
6 {Ski-Tracks}, Select (vBody_Volume, 30, 3, 100, 4, 300, 4, 3000, 5, 5), 0)) +
IIF(vHas_Improved_Suspension, 1, 0) +
IIF (vIndex_Ground_Type = 0 {Legs} & vTL <= 7, -1, 0) +
IIF (vHas_Harness, -1, 0) +
IIF (vHas_Articulated_Hull, 1, 0)+
IIF (vHas_Underbelly_Skid, Select (vBody_Volume, 30, 1, 100, 2, 300, 2, 3000, 3, 3), 0)

Performance Profile Formula 9 (Ground Pressure): Should be:
IIF((vVehicle_Weight - vTOTAL_PROFILE_MOTIVE_LIFT) < (vVehicle_Weight * 0.1),
vVehicle_Weight * 0.1,
vVehicle_Weight - vTotal_Profile_Motive_Lift) /
IIF (vHas_Flexibody, vBody_Surface_Area / 6,
IIF (vHAS_UNDERBELLY_SKID, vBody_Surface_AREA / 20,
vTotal_Profile_Motive_Surface_Area *
Decode (vIndex_Ground_Type,
1 {Legs}, 0.08,
2 {Skids}, 0.1,
4 {Tracks}, 0.2,
5 {Half-tracks}, 0.05,
6 {Ski-Tracks}, 0.1, 0.02)))


Once you have finished cutting and pasting these three formulas. Press OK to close the edit template dialog, then press F10 to save the repositories. Finally, delete the existing not wheeled ground performace profile from your vehicle(s) and replace it with the updated version.

If you have questions about this workaround, let me know and I'll see if I can fix the problem.
__________________
Thomas Jones-Low: tjoneslow@gmail.com
Vehicle Builder Guru and gearhead
Librarian at Traveller Wiki
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Old 03-01-2007, 03:47 PM   #3
tjoneslo
 
Join Date: Aug 2004
Location: Vermont
Default Re: Getting underbelly skids to work

The above is not quite correct. There are three more formulas to fix and one of the above ones has another bug which makes your vechicle still wrong:

Performance Profile 5: gDecel:
IIF (vHas_Flexibody, 20,
IIF (vHAS_Underbelly_skid, 6,
Decode (vIndex_Ground_Type,
1 {Legs}, 20,
2 {Skids}, 6,
4 {Tracks}, 20,
5 {Half-tracks}, 20,
6 {Ski-Tracks}, 15, 0)))

Performance Profile Formula 6 (unnamed):

IIF (vHas_Flexibody, Select (vBody_Volume, 30, 2.5, 100, 2, 300, 1.5, 3000, 1, 0.5),
Decode (vIndex_Ground_Type,
1 {Legs}, Decode (Range (vTOTAL_PROFILE_MOTIVE_ITEMS, 2, 4),
2, Select (vBody_Volume, 30, 2.5, 100, 2, 300, 1.5, 3000, 1, 0.5),
3, Select (vBody_Volume, 30, 2, 100, 1.5, 300, 1, 3000, 0.75, 0.5),
4, Select (vBody_Volume, 30, 1.25, 100, 1, 300, 0.75, 3000, 0.5, 0.5), 0),
2 {Skids}, Select (vBody_Volume, 30, 1.25, 100, 1, 300, 0.75, 3000, 0.25, 0.125),
4 {Tracks}, Select (vBody_Volume, 30, 0.5, 100, 0.25, 300, 0.25, 3000, 0.25, 0.125),
5 {Half-tracks}, Select (vBody_Volume, 30, 0.5, 100, 0.25, 300, 0.25, 3000, 0.25, 0.125),
6 {Ski-Tracks}, Select (vBody_Volume, 30, 0.5, 100, 0.25, 300, 0.25, 3000, 0.25, 0.125), 0)) +
IIF(vHas_Improved_Suspension, 0.25, 0) +
IIF(vIndex_Control_Type = 2 {Computerized}, 0.25, 0) +
IIF(vIndex_Control_Type = 3 {Electronic}, 0.25, 0) +
IIF(vHas_Responsive_Structure, 0.25, 0) +
IIF(vHas_Smart_System, 0.25, 0) +
IIF(vHas_Underbelly_Skid, Select (vBody_Volume, 30, 1.25, 100, 1, 300, 0.75, 3000, 0.25, 0.125), 0)

Performance Profile Formula 7 (gMR):
IIF (Checkbox(1) {uses harnessed animals} | Checkbox(2) {uses sails} |
(vHas_Rotors & !vHas_Folding_Rotors) |
(vHas_Wings & !vHas_Folding_Wings),
MIN (0.5, IIF (vBody_Volume > 3000 & vPP6 {gSR} > 0.125, vPP6-0.125, vPP6)),
IIF (vBody_Volume > 3000 & vPP6 {gSR} > 0.125, vPP6-0.125, vPP6))

and the formula for gSR (Formula 8) replace the part that reads
IIF (vIndex_Ground_Type = 0 {Legs}

with
IIF (vIndex_Ground_Type = 1 {Legs}
__________________
Thomas Jones-Low: tjoneslow@gmail.com
Vehicle Builder Guru and gearhead
Librarian at Traveller Wiki
tjoneslo is offline   Reply With Quote
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