The present invention is an ordnance fuze power source assembled from commercially available cells to form, fit and function in place of the lead/lead dioxide/fluboric acid spin activated reserve batteries now used by the Army and the Navy. Specifically, direct replacements for the U.S. Army HDL P/N 11744726 and 5058639 power sources were made using a series connection of commercially produced lithium anode cells in series with an acceleration activated switch supported in an epoxy matrix. However, the invention is applicable to other fuze power sources as well. Adoption of this invention by the armed forces will ease the logistics burden at the onset of a national emergency by providing a readily available supply of fuze batteries.

A method of producing multiple coil, multiple tube heat exchanger from circular tubes, in which alternating turns in each coil have a warmer liquid and other turns a cooler liquid, by coating the outside of each coil with a heat conductive mastic and winding the next coil against the mastic to force the mastic into spaces between adjoining tubes of the first coil, into spaces of adjoining tubes of the second coil and into spaces between opposed tubes of first and second coils. Mastic applied to outside of each coli or into grooves between turns as next coil wound. Double tubes of each coil preferably wound into grooves between turns of preceding coil. Second tube of each coil started across coil from first tube and continued at end of coil past first tube. Succeeding coils wound against mastic in same manner. Turns of first coil attached together, as by soldering, while first and last turns of succeeding coils similarly attached to adjacent turn of coil beneath. Succeeding coils may be terminated between second and third turns of coil beneath, or with appropriate inner diameter of first coil, terminated between last two turns of coil beneath. Several coils may be formed of tubing of the same diameter, with additional coils of tubing of greater diameter, all coils of tubing of same diameter, or all coils of tubing of successively increasing diameter. Length of coils proportioned with respect to diameter of tubing so that liquid will take the same amount of time to flow from one end of each coil to the other.

A mode selector device, such as might be used in a projectile, allowing a simple manual adjustment before firing time to enable a function upon firing. A safe, small, reliable, "fail-useful" mechanism using shock to activate a cutter which removes a particular short in the circuit for each of a plurality of functions.