The Unoffial 2056 Vehicle Guide

[juris]

That's my take too. Ironically HD Transmissions aren't that great for towing unless you think a fully loaded car-trailer combo with a top speed of 60 is a good idea. This limits the vehicle's range because range is based on how fast you're going vs your vehicle's top speed.


Again, it's like they didn't think this stuff through. HDTs are good for specialized arena-tank vehicles. Fully loaded gas burners are even more ridiculous with HDTs - their TS drops to 30mph!

Originally Posted by swordtart

Whether that extra load is on the chassis or a trailer is immaterial.

[43Supporter]

Originally Posted by swordtart

If you argue that HDT "does not affect the PF count" then it can't tow extra weight either (compare rigs).

Not necessarily -- as you say:

Originally Posted by swordtart

I can see what you mean though, power is work done over time and you are not changing that with HDT, you are delivering more work but taking more time to do it (lower Acc, lower top speed etc.). Whilst PF chimes well with HP (the usual means of describing vehicle power), we are considering different gearing as well with the HDT and the default CW speed calculation takes no account of gearing, just raw power.

That's where our interp came from -- it would be like trying to run a real-world (pardon the usage of that term) semi-tractor using the diesel engine from a family hatchback. One needs an engine powerful enough to deal with all that mass; it isn't enough to hang a stump-puller transmission off the end of any old engine, and expect it to work. So, we required the powerplant to have the necessary 1/3-PF (or, to put it in terms of the Big Rig Rules, 1x Maximum Load).

This still leaves the HD Trans as a workable concept, BTW. For ex.: A XH-chassis Lux, fully-loaded, is 6,600 lbs -- that's a Large plant with SCs, at 2,200 PF dead-on [phrased another way: 6,600 Max. Load]. Add HD Trans, doubling for towing [13,200 lbs. ML], and one can then strap a 10' Van trailer to the back, another 5,700 or so lbs. -- essentially adding another Lux to the Lux one is already using. (It's going to be a spendy beast, but....)

I'd include a design here, but I never worked much with car-trailers; those hitches and tongues had a nasty habit of getting shot off. :)

[swordtart]

Originally Posted by 43Supporter

...One needs an engine powerful enough to deal with all that mass; it isn't enough to hang a stump-puller transmission off the end of any old engine, and expect it to work. So, we required the powerplant to have the necessary 1/3-PF (or, to put it in terms of the Big Rig Rules, 1x Maximum Load)...

Errrr... A small plant can't pull a Sedan even with a HDT. This meets your "real world" limitation without adding an arbitrary limit.

Sorry, NOVA got this ruling wrong. HDTs are sufficiently balanced as they are.

[43Supporter]

Originally Posted by swordtart

Errrr... A small plant can't pull a Sedan even with a HDT.

It only becomes relevant in the "edge cases". For ex.:

Small PP, no mods, is 800 PF (or 2,400 lbs. max. ld.). This would be inadequate to move a XH-chassis Compact (4,440 lbs. loaded).

Add HD Trans, and if one interprets the HD Trans rules broadly, that Small PP would have enough max. ld. to move the XH-Compact (4,800 ML > 4,440 lbs. mass). Looking at the designs in _Combat Showcase_: This appears to be how the vehicle designers for that supplement interpreted it.

Conversely: One looks at HD Trans designs in _VG2_ and later, and it appears the interpretation has changed to the one NOVA used (see the _Buffalo_ and _Clydesdale_ designs, specifically).

I'd have to dive into the old _ADQ_s to see if "ADQ&A" has any references to the topic; but as far as I can remember, the last "official" interp was "one needs enough PFs to move the car without the HD Trans".

[juris]

The 2.5e Compendium says the HD doubles power factors for purposes of maximum load the vehicle can carry or pull, not maximum speed or mileage.

Not sure what this discussion is about the rule seems clear to me.

[43Supporter]

Originally Posted by juris

The 2.5e Compendium says the HD doubles power factors for purposes of maximum load the vehicle can carry or pull, not maximum speed or mileage.

And immediately after that: "*NOT* for maximum speed or [....] acceleration", which says "one still needs adequate Power Factors before HD Trans is added".

Still digging through "ADQ&A" -- times like these, a wiki would be *really* handy.... :)

[swordtart]

Originally Posted by 43Supporter

Conversely: One looks at HD Trans designs in _VG2_ and later, and it appears the interpretation has changed to the one NOVA used (see the _Buffalo_ and _Clydesdale_ designs, specifically).

I don't agree. See the Chopper (also in VG2). This is a 7,796lb pickup with a Medium Plant. Without HDT this thing wouldn't move.

Your examples both have trailer hitches and so are designed for towing. Clearly you would design them with enough spare capacity to handle the extra load from the trailer, this isn't evidence that you have to use a trailer to benefit from HDT.

I couldn't find anything concerning this in my ADQ&A database (though I have a few editions that are not digitised).

You needn't keep quoting worked examples of how the rules are used. I can handle the maths (since it boils down to multiplying by 2, I doubt there is a CW player out there that can't handle it and that makes it insulting).

No-one is disputing that a HDT doubles your effective PFs, the only dispute is that you assert that it is only good for pulling trailers. You are the only one espousing this view and you have yet to provide any evidence to back up this interpretation, whereas I have provided published designs demonstrating that the canon view is that HDT effectively double PFs regardless of whether you have a trailer or not.

You interpretation also defies common sense and basic physics. If an engine can move a car massing 3000lb with 1000lb on-board cargo, it can equally pull the same 3000lb car towing a trailer with an all up mass of 1000lb and vice-versa. We can ignore any extra friction due to the extra axle on the trailer as a 6 wheel chassis doesn't degrade your performance compared to a 4 wheel one in CW.

[swordtart]

I was hoping to post a credible design for an electric vehicle using HDT for non trailer purposes, but I am finding it hard to come up with something that is better with HDT rather than spending the 2 spaces and 300lb buying a plant a few sizes up.

No subcompact can afford to throw away so much of its space and weight budget. Similarly compacts. Midsize max loads are not ideal matches for the 2X PF of the small plant unless you start putting in SCs and PCs (which pushes you plant cost even higher making a larger plant make more sense).

Pick-ups, Campers and Vans all need 6 tires for extra heavy chassis and with decent tires this builds in cost and weight. I haven't found the HDT to be efficient enough for them.

Which leaves Lux, Sedans and Station Wagons which are easily within the capacity of an un-upgraded Medium plant with HDT. Unfortunately they are also easily within the range of a Large plant with SCs (indeed this plant is optimal for the XHvy chassis, Hvy chassis can get away with PCs). The cost saving is marginal $600, but you are 100lb and 1 space worse off in addition to the adverse performance. I suspect you could find that $600 saving more easily than the space and weight saving.

Still, I am going to reverse engineer the Chopper to use a conventional plant and also see if I can come up with a credible Station Wagon (since that vehicle screams "mum's taxi" to me)

I haven't done the same analysis on gas plants, these may well fit better into the power bands. I am mindful of the very poor stop speed issue though.

[swordtart]

Hmmm, Chopper doesn't seem to add up ;( This may be more work than I thought.

[43Supporter]

Originally Posted by swordtart

Hmmm, Chopper doesn't seem to add up ;( This may be more work than I thought.

I know -- I had to rework that one myself, back-when:

CHP-3R

Pickup; XH chas.; Hv. susp.; Su. PP [2,600 PF]; 6x PR Rad. tire; Dr. VFRP [LG] [F]; IRTL w/LGL (L: VFRP) [F]; FOJ (L: VFRP) [B]; Cargo: (11) sp.|3 lbs.; Spoiler/Airdam. Armor: Body: 272 pts. P [F: 85; L, R: 55; B: 65; T: 2; U: 10]; Tires: 4x 10-pt. WH; 4x 10-pt. WG. $29,859; 7,800 lbs. Acc.: 5; TS: 90; HC: 3 (-1D)

-3G Opt.: rm. VFRP, IRTL, LGL, Link [VFRP-IRTL]; add GG [F], SD [Inc. am.] [B], 2x Link [FOJ-SD; GG-FOJ-SD], SWC [GG]. $29,959

-3MG Opt.: rm. VFRP, IRTL, LGL, Link [VFRP-IRTL]; add 2x MG (L) [F], SD [Inc. am.] [B], 2x Link [FOJ-SD; MGs-FOJ-SD], SWC [MGs]. $22,509

/OR Opt.: rm. Hv. susp., PR Rad. tires, Airdam, 20 pts. WG arm., 7 pts. B arm.; add OR susp., 7x OR Sol. tire [1 spare in cargo sp.], Brushcutter, Tool Kit, 7 lbs. cargo. +$4,146

(The Gauss Gun model is particularly infamous, as I used it in an arena to not only eliminate all three of my opponents -- to include a one-shot kill through someone's Top -- but in the process taking *zero* damage; this sort of domination led to my getting thrown out of NOVA.)

I did a walk through my _ADQ_ PDFs -- I could only find *one* reference to the question, in _ADQ 4/4_'s "ADQ&A". I will concede: Haring's answer agrees with you. However, I don't have any PDFs of _Pyramid_, so there might be info in there I don't have. (Also: The only other ref to HD Trans I could find in *all* of the relevant _ADQ_s is someone asking if it can be turned on|off. It appears people quit using HD Trans after PCs and SCs appeared in _ADQ 6/1_ -- not surprising, considering the cost and performance benefits.)

But, as Haring's response is the "most recent" answer, I'll abide by it.