Franklin Engine

The Franklin Engine

The invention of Grand Wizard Benjamin Franklin, the Franklin Engine is a Mana Engine (Spaceships 7, pp 13) which provides only Magical Power Points (MP). They produce 1MP per system. The Engine is built around a core ur-ice element which provides power for up to five years under normal useage, and is usually shielded with a layer of gold filigree as a dampener against the dangerous mana emanations that cause Twists in those exposed to too much ur-ice or magic.

Franklin Engine
Mechanic (Magical Power Plant).
SM +5 +6 +7 +8 +9 +10 +111 +12 +13 +14 +15
Workspaces 0 0 0 0 0 1 3 10 30 100 300
Cost ($) 100K 300K 1M 3M 10M 30M 100M 300M 1B 3B 10B

1 SM+11 is the largest practical size for wooden ships of the kind seen in Arcanum, Engines larger than this are ground-based installations.

Franklin Engines can be used for a variety of purposes. The most common is to power the contra-gravity devices that do the heavy lifting in Skyships, but they can also power magical lighting, heating and so forth in large buildings or even entire towns. Unfortunately, no one has yet succeeded in making a portable Franklin Engine smaller than those which fit in Skyships, of which the smallest weighs in at about the same as a semi-portable steam engine (HT14) or around 4 tons.


A Franklin Engine can act as a magical “Place Of Power” for a mage in physical contact with it. The Engine provides a plus to energy gathering rolls equal to the base SM of the skyship for which that Engine would be appropriate. In many warships and some merchantmen a copper conduit is run to a position on the quarterdeck so that a mage can be in effective contact with the Engine yet still cast spells effectively, as Engines are usually buried deep in the ship’s core.

If an Engine is destroyed in combat or otherwise while in use, it explodes doing SMx10D ex inc damage and causes SM/2 round down number of SMx20 energy Botches.

Franklin engines are more efficient because they destroy the crystals over a period to release their magical energy in a controllable fashion, so the crystals needn’t be in one chunk or even cut. Fuel costs per year of operation are as follows:

Ur-Ice Gem Cost
SM Cost($) Carats
5 $100k 1,000
6 $150k 1,500
7 $200k 2,000
8 $300k 3,000
9 $500k 5,000
10 $700k 7,000

And so on, following this progression. These prices are based upon 0.2 carat raw uncut gems with no gold protection surrounding them, which is where the price per carat bottoms out; smaller ones are available, but they cost the same amount on a per-weight basis.

Franklin Engine

Arcanum 1780: A New World Cernig