I agree there are crossbow-type weapons that are very powerful. However, 1,200 lbs draw weight is not a typical crossbow. That is a later period steel-proded piece, and were typically used with a pavise (portable shield), two assistants and infantry in support. A good many were dolly mounted. Payne-Gallwey’s book was written in 1886, when it was still believed that a longbow was at most 70 lbs of draw, and that the stories from the Hundred Years War were exaggerated. We have since found archaeological evidence that supports the longbow. (Not to mention all the dead crossbowmen at the Battle of Crecy.) Also keep in mind that these heavy crossbows weighed a lot more than the 2-3 lbs of a longbow, and required external mechanisms–cranequin or windlass–to be attached and detached between every shot. There were specific needs for those weapons, but it’s not something the typical survivalist should worry about. The larger arbalests shot what amounted to short, heavy javelins that certainly had better range than any tactically employed bow, but the rate of fire was greatly reduced.
The main consideration for power is that there is a limit to the velocity one can accelerate an arrow to. All things being equal, the longbow’s greater draw length allows more arrow mass that retains velocity better. A 700 lb crossbow accelerates its bolt to about the same 130 fps an 80 lb longbow does…and a recurve is much more efficient than most longbows. The heartwood/sapwood Welsh bow is the textbook “longbow” in this discussion. There are definitely crossbows that have better range than most normal longbows. But when the subject is hand-spanned bows without external cocking aids, the longbow or recurve is far superior in range. In both cases, modern materials provide superior results–fiberglass crossbows achieve better range and velocity with a lower draw weight because of reduced internal friction, lighter string mass and better acceleration of the prod under tension.
The crossbow has several advantages I mentioned but didn’t detail at length. If the first shot counts (and a crossbow is easier to aim), all is well and good. But the longbow archer will get off multiple shots in return before the crossbow is ready again. Both have their place. For defense inside the house or other close quarters, I’d certainly go with a crossbow, as it is easier to wield within the confines, and one can have a shot ready for an intruder at one’s moment of choice. Against multiple opponents at range, however, the longbow (or recurve) comes into its own. Also consider that a crossbow string gets more friction from the stock and release mechanism and will wear out faster.
The re-enactor groups also have plans for both tension and torsion driven engines, as well as for counterweight types (Trebuchets) which can hurl spear-sized projectiles several hundred yards. I haven’t built one, but they are typically constructed of standard 2 x 4s and 2 x 6s, often with pick handles as the arms. These are certainly viable point defense weapons to conserve firearm ammunition, though they are bulky.- Michael Z. Williamson