Hello all,
From determining the hull to the sensors in the TD #13 design example and the addition of TD #21 by Donald McKinney's edited example has been relatively easy to work with. The areas that are throwing a kink in the process starts with the environmental control section, estimation of the crew. power supply section, and the Fuel & Miscellaneous Section.
1. In the Environmental Controls section the example remove the jump fuel tankage volume reducing the basic and extended life support systems requirements.
2. Estimating the crew is used to determine the stateroom volume which is subtracted from the running volume total.
3. The power supply volume/units are estimated by using the input power needed to operate the maneuver drive to the environmental controls reduced power requirements after taking the jump fuel tankage out of the equation. Both the original and the edited example calculate and subtract the stateroom volume. Neither of them mention calculating or including the power drawn by the staterooms to the in to the total power calculation.
4.The example determines the volume of the power plant. TD #13 has the volume as 177,778 kl and Donald's edited copy, as 181, 910 kl. Not including the power needed to operate the staterooms should increase the power needed which alters the volume calculations
5. The example indicates the "...need to consider fuel and duration needs to see how reasonable the power plant is." since the calculated volume takes over half the remaining volume. This is the point that the fuel consumption rate is determined by looking at the power supply table.
6. The example then determines the requirements for the jump fuel purification plant and adds them to the Net Total so far calculations table.
7. Power plant fuel tankage is finally determined by using the "design tip" of including a modifier for installing a fuel purification plant. The volume of 181,910 kl is used to determine the power plant fuel tankage. The calculated power used to determine the power plant volume does not include the power requirements of the staterooms and jump fuel purification plants.
8. The calculated power plant fuel tankage exceeds the remaining volume.
9. TD #13 example reduces the MD from 6 to 2 and the edited example drops the rating to 1 regaining some volume that allows the power plant fuel tankage to barely fit.
10. The edited example goes one step further by changing the JD from 4 to 3. This change reduces the jump fuel tankage and the size of the fuel purification plant.
11. The changes made in items 9 and 10 decreases the power drawn from the power plant reducing the power plant requirements and fuel tankage.
I'm having some trouble in getting my rough spreadsheet working following the process outlined above, but I do have some comments that can be made now.
I agree that the power plant specifications should be determined later than Step 2 as shown in 0 - Overall Craft Design 3 Design Craft by Section A2 on page 62 of MT Referee's Manual.
The example's positioning for estimating the power plant specification is, in my opinion, slightly out of order as presented.
The power requirement used to estimate the power supply requirements used in the examples should be in my opinion: Locomotion Power Total + Communications Power Total + Sensors Power Total + Weapons Power Total + Screens Power Total + Environmental Controls Total + Stateroom Power Total + Jump Fuel Purification Plant Power Total.
My preference is the determine the power requirements for all systems and then determine the power plant size which appears to have worked in a draft spreadsheet I made skipping TD #13 and the edited example. Unfortunately, my cargo space does not match either TD #13 or edited example cargo space.
Tom Rux