Alright, I have this scene, well two scenes in my head, one involving catapults/trebuchets and the other horses and I need some questions involving the certain physics to each concept. Catapults/Trebuchets Starting off here with Catapults and Trebuchets. Basically the scene I want to depict in the story is where an encroaching force (an army if you will) begins to invade from a mountain pass (a low pass in the mountain range with mountains on each side). I was thinking of a defense mechanism were projectiles would be flung to hit the surrounding mountains causing rocks and stones to fall initiating an avalanche to block the pass. Now the basic question here is what will be more realistic and/or cause the best effect. From what I researched Catapults are small-medium sized and use some type of elastic to fling the projectile whereas trebuchets are large in side and use a counterweight to fling the projectile. Which one will initiate an avalanche to block the pass? If is trebuchet would it be too large? And if it is catapult, can it even shoot that high with enough force? Horses Second concept is horses. I just need some realistic physics here. Think Peter Jackson's Lord of the Rings the Two Towers movie where Gandalf and Eomer charge down horseback to liberate Helm's Deep. Obviously this is unrealistic as cliff is too steep and the degree of the angle would either slow the horses to canter down or make them trip over themselves causing massive fail. What I need here is what is the maximum degree of angle which horses can sprint/gallop down from a hill. I plan to use this regarding a scene-in-progress which I will later work on.
first off the whole avalanche thing is possible thou part of me wonders if its probable Catapults have been used to cause avalanches if my history is correct but i don't think they can cause a really good avalanche with out luck and to hit the "Sweet spot" you have to have a clear shot, that shot might make them get to close it really depends on the shape of the mountains and where these guys are positioned if it hits a Castle it only effects a small amount (the rest of it stays intact) as far as i can tell same would be the same fro a mounting (since there both made of stone) now a rock slide is probable but if we where to go out and try it now i think three things could happen A nothing we just made some pebbles fall B. we just killed our selfs cause we had to get close to hit it just right C we just tapped them and are safe now we have to worry about the air forces Catapult seems like the best bet to me first le me say they should have that fail in a blooper real (or at the actors funeral) as for this one i cant say with out taking a horse down a hill and finding out (and i really don't want to die)
For the avalanche, I'd recommend catapults. They're smaller, easier to move around, and if you're talking about starting an avalanche that means it must have snowed recently, so you really don't want to try moving the larger, heavier trebuchets through snow or half-frozen mud. So transport and logistics will be an issue, especially during a war. Plus, the catapult operators will be a specially trained segment of your army, and they won't be as good at "regular soldier" tactics if the catapults are lost; plus if the catapult crews get taken, you've lost weeks or months of training before they can be replaced. (Not to mention the problem of your enemies possibly saying, "Either you tell us how to most easily destroy your catapults, or we cut off your hands. What do you say?") As for the slope steepness issue, go with a relatively gentle grade. Remember, charging horses can't stop quickly or easily, and rough terrain of any kind will increase the likelihood of a horse tripping and falling, possibly rolling over and thereby crushing its rider, or tripping other horses and killing their riders. Unknown ground is worse, as well as foggy ground, marshy / boggy ground, or horribly rocky scraggy ground. Anything worse than "very gently rolling hills" is a poor thing for cavalry charges. It's just too risky for the horse and rider to work on rough or tilted terrain, and heavy mounted cavalrymen take years to train; plus it takes years to train horses to charge like that. (An untrained horse in a battle is a danger to everything around it, and will probably get its rider killed. A partially-trained horse will shy away at the last minute, spoiling your lancer's aim and, again, possibly getting the rider killed. Plus untrained horses get really nervous around the smell of blood.) And riders generally won't risk their mounts without very good reason. After working with a horse and training with a horse for four or five years, there's no way most riders will put their horses in danger needlessly. Charging downhill over rough ground? The kingdom had better be about to fall, or your soldiers might well disobey the commanding officer ... and an officer who'd risk such a valuable fighting force as heavy cavalry without cause will likely be dismissed anyway. I mean, "The Prince is about to die! Charge and save him!" might not even be a good enough reason. If the Prince might die anyway, and if there's a spare or better-loved heir to the throne . . . It makes more sense to only have the cavalry charge in dangerous conditions in order to turn the tide of battle, or cut off a hated enemy's escape.
Hmm seems catapults are the best bet, I thought trebuchets because I assumed they would do more damage on the surrounding mountains. @wolfi: yes they needed that epic fail at the blooper reel XD. @HeinlienFan: Well when I meant avalanche I meant the avalanche-in-action not the specific term. I guess a more similar term would be rock collapse or rock slide; the goal is to hit the surround mountains with projectiles and break some of that rock/stone off to block the pass from the encroaching force.
Catapults are, historically, fairly light pieces of kit. You'd need a lot of them to cause any kind of significant rock-slide. Trebuchets are a better bet (heavier duty, capable of hurling more weight over further distances), but they'd have to be an in-situ defence mechanism, as they're not easily moveable (to give you an idea, Genghis Khan's city-wall smashing catapults took over a day to erect and then took days to hammer a city wall flat – a trebuchet would do the job quicker but probably take a week to build a decent size one). As for the horse question – lightly armoured horses and scouts can charge down amazingly steep terrain (again, see Genghis' charges against the Russians down steep, uneven ground with more than 10,000 horses as evidence of this), but only an idiot would risk this unless absolutely necessary. Heavy cavalry would never, and I do mean never, charge down anything but a gentle incline.
