Jump Transit Times

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adzling
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Jump Transit Times

Postby adzling » Sun Feb 07, 2021 8:16 pm

Ahoi Travellers, looking at the mg2e core rules we see that the transit time for a 2g ship to traverse 1,000,000km is 236 minutes..

Meanwhile T5 traveller worlds pegs it at 23m & 24 seconds....

Anyone know what's going on?

thanks!
Condottiere
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Re: Jump Transit Times

Postby Condottiere » Sun Feb 07, 2021 11:09 pm

Find the original algorithm.
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adzling
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Re: Jump Transit Times

Postby adzling » Sun Feb 07, 2021 11:27 pm

looks like Traveller Worlds has a decimal place wrong, it should be @236 minutes from jump transit to world, with constant acceleration to halfway point and constant deceleration until destination.
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paltrysum
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Re: Jump Transit Times

Postby paltrysum » Mon Feb 08, 2021 1:28 am

Where’d you find the formula, adzling? I know that it can be found on the Traveller Discord Server.
My published Traveller adventures on DriveThruRPG:
https://www.drivethrurpg.com/browse.php ... %20Griffen
Old School
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Re: Jump Transit Times

Postby Old School » Mon Feb 08, 2021 2:41 am

I usually use:

https://www.calculatorsoup.com/calculat ... _v_a_t.php

1G of acceleration is 9.8m/s^2
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adzling
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Re: Jump Transit Times

Postby adzling » Mon Feb 08, 2021 3:00 am

Paltry i got lots of help on the reddit traveller forum that allowed me to construct an traveller accurate spacecraft chase across 3 systems..

There are three two vessels...
The Voidskipper, an M2, J2, double-tankage Beowulf class far trader & the Themasus a M2, J2 double-tankage Eirickson class scout.

The Darkstar, a 400 ton M2, J3 scout survey vessel (restricted to jump 2 due to system locations).

They both jump from BT-SHT 365 to Thalassa.

--The Darkstar starts with 38.5 hour lead--
Darkstar time to depart Thalassa system:
148+6d6 hours (core p.148) to Thalassa.
Transit time from the jump point to Thalassa (at a constant 2g acceleration to halfway and then constant deceleration to orbit) is ((sqrt ((2 x 12,800,000 x 50) / (2 x 9.8)))2)/60 = 269 minutes!
Assuming they landed on Thalassa to refuel then we add-
24 minutes to land on the surface from orbit (see page 153 core)
30 minutes to start refueling.
60-360 minutes to refuel (from page 147 core)
24 minutes to reach orbit.
Transit to jump point at constant 2g acceleration is (sqrt ( (2 x 12,800,000 x 100) / (2 x 9.8) ))/60 = 190 minutes!
=10-15 hours in system at Thalassa
=164-199 Hours to depart Thalassa system.

Voidskipper's time to Thalassa system:
148+6d6+38.5 hours to jump to Thalassa
=192.5-222.5 hours to arrive Thalassa system

odds are they just missed her!

Darkstar has a Jump time of somewhere between 164+199 hours + 148+6d6+0.5 hours to Homestead.
Darkstar arrives in Homestead system 318-383 hours after departing Varmada (assuming no gas giant refueling or other delays)

Voidskipper's time to arrive Homestead system:
1d6 x 10 minutes to plot new astrogation course + 1d6x10 minutes to fire the drives up again and initiate jump = 20-120 minutes to jump (core p.148)
Jump time of somewhere between 192.5-222.5 hours + 148+6d6 + 0.3-2 hours to Homestead.
Voidskipper Fleet arrives in Homestead 346.8-408.5 hours after the Darkstar departed Varmada

Darkstar time in system at Homestead might look like:
Transit time to Homestead from the jump point at a constant 2g acceleration to halfway and then constant deceleration until orbit is @((sqrt ((2 x 8,000,000 x 50) / (2 x 9.8)))2)/60 = 212 minutes!
Assuming they landed on Thalassa to refuel then we add-
24 minutes to land on the surface from orbit (see page 153 core)
30 minutes to start refueling
60-360 minutes to refuel (from page 147 core)
1200 minutes to process fuel
24 minutes to reach orbit.
Transit to jump point at constant 2g acceleration is (sqrt ( (2 x 8,000,000 x 100) / (2 x 9.8) ))/60 = 150 minutes!
Darkstar has 28-33 hours in system at Homestead
Darkstar departs Homestead 346-416 hours after departing Varmada

TL:DR It's going to be close but it looks like the Voidskipper might catch the Darkstar before she departs Homestead, if indeed she came this way...
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paltrysum
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Re: Jump Transit Times

Postby paltrysum » Mon Feb 08, 2021 4:01 am

Excellent. Love that you’re using the Voidskipper by the way, from “Last Flight of the Amuar.”
My published Traveller adventures on DriveThruRPG:
https://www.drivethrurpg.com/browse.php ... %20Griffen
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adzling
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Re: Jump Transit Times

Postby adzling » Mon Feb 08, 2021 4:41 pm

Kept the Voidskipper name and concept but replaced with a beowulf far-trader with collapsible tanks and other customizations.
They procured her with their ship shares and picked her up as a substitute for the HighNdry Scout in the adventure of the same name before transiting down to Pax Rulin to pick up the Last Flight of the Amuar.
They just finished up BT-SHT 365 and are chasing the 400 ton Donosev class scout Darkstar as it flees to Vorito with a very valuable artifact on it.

The crew will be attempting to intercept the Darkstar at Homestead as she departs the system.

The double-jump capability of their ships coupled with some excellent Astrogation and Jump Drive checks (companion page 142) may allow them to make up the time and catch her.

It will be fun to see...

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