Length
A longbow must be long enough to allow its user to
draw the string to a point on the face or body, and the length therefore varies with the user. In continental Europe it was generally seen as any bow longer than 1.2 m (4 ft). The
Society of Antiquaries says it is of 5 or 6 feet (1.5-1.83 m) in length.
[11] Richard Bartelot, of the
Royal Artillery Institution, said that the bow was of yew, 6 feet (1.83 m) long, with a 3 foot (914 mm) arrow.
[12] Gaston Phoebus, in 1388, wrote that a longbow should be "of yew or boxwood, seventy inches [1.78 m] between the points of attachment for the cord".
[13] Historian
Jim Bradbury said they were an average of about 5 feet and 8 inches.
[14] All but the last estimate were made before the excavation of the
Mary Rose where the bows were found to range in length from 1.87 to 2.11 m (6 ft 1 in to 6 ft 11 in) with an average length of 1.98 m (6 ft 6 in).
[15]
[edit] Range and penetration
The range of the medieval weapon is unknown, with estimates from 165 to 228 m (180 to 249 yds). Modern longbows have a useful range up to 180 m (200 yd). A 667N(150 lbf)
Mary Rose replica longbow was able to shoot a 53.6 g (1.9 oz) arrow 328 m (360 yd) and a 95.9 g (3.3 oz) a distance of 249.9 m (272 yd).
[16] A flight arrow of a professional archer of Edward III's time would reach 400yds. It is also well known that no practice range was allowed to be less than 220yds by order of Henry VIII.
[17]
The longbow had a long range and high accuracy, but not both at the same time. Most of the longer range shooting mentioned in stories was not marksmanship, but rather thousands of archers launching volleys of arrows at an entire army. Longbowmen armies would aim at an area and shoot a rain of arrows hitting indiscriminately at anyone in the area, a decidedly
un-chivalrous but highly effective means of combat. An archer could hit a person at 165 m (180 yards) "part of the time" and could always hit an army.[
citation needed]
Gerald of Wales commented on the power of the Welsh longbow in the 12th century:
...
n the war against the Welsh, one of the men of arms was struck by an arrow shot at him by a Welshman. It went right through his thigh, high up, where it was protected inside and outside the leg by his iron cuirasses, and then through the skirt of his leather tunic; next it penetrated that part of the saddle which is called the alva or seat; and finally it lodged in his horse, driving so deep that it killed the animal.[18]
However, even heavy draw longbows have trouble penetrating well made steel plate armour, which was used increasingly after 1350. A 2006 test was made by Matheus Bane using a 75 lbf (330 N) draw (at 28") bow, shooting at 10 yards; according to Bane's calculations, this would be approximately equivalent to a 110 lbf (490 N) bow at 250 yards.[21] Measured against a replica of the thinnest contemporary "Jack coat" armour, a 905 grain needle bodkin and a 935 grain curved broadhead penetrated over 3.5 inches (89 mm). ("Jack coat" armour could be up to twice as thick as the coat tested; in Bane's opinion such a thick coat would have stopped bodkin arrows but not the cutting force of broadhead arrows.) Against "high quality riveted maille", the needle bodkin and curved broadhead penetrated 2.8". Against a coat of plates, the needle bodkin achieved 0.3" penetration. The curved broadhead did not penetrate but caused 0.3" of deformation of the metal. Results against plate armour of "minimum thickness" (1.2mm) were similar to the coat of plates, in that the needle bodkin penetrated a small amount, the other arrows did not penetrate. In Bane's view, the plate armour would have kept out all the arrows if thicker or worn with more padding.
Other modern tests described by Bane include those by Williams (which concluded that longbows could not penetrate maille, but in Bane's view did not use a realistic arrow tip), Robert Hardy's tests (which achieved broadly similar results to Bane), and a Primitive Archer test which demonstrated that a longbow could penetrate a plate armour breastplate. However the Primitive Archer test used a 160 lbf (710 N) longbow at point blank range, generating 160 joules (vs. 73 for Bane and 80 for Williams), so probably not representative of battles of the time. Other research has also concluded that later medieval armour, such as that of the Italian city state mercenary companies, was effective at stopping contemporary arrows.[22] Archery was described by contemporaries as ineffective against plate armour in the Battle of Neville's Cross (1346), the siege of Bergerac (1345), and the Battle of Poitiers (1356); such armour became available to European knights of fairly modest means by the late 14th century, though never to all soldiers in any army. Strickland and Hardy suggest that "even at a range of 240 yards heavy war arrows shot from bows of poundages in the mid- to upper range possessed by the Mary Rose bows would have been capable of killing or severely wounding men equipped with armour of wrought iron. Higher-quality armour of steel would have given considerably greater protection, which accords well with the experience of Oxford's men against the elite French vanguard at Poitiers in 1356, and des Ursin's statement that the French knights of the first ranks at Agincourt, which included some of the most important (and thus best-equipped) nobles, remained comparatively unhurt by the English arrows."[23]
Modern tests and contemporary accounts agree therefore that well made plate armour could keep out longbows, however there are a number of caveats to this point; not all plate armour was well made or well looked after, and there were also weak points in the eye and air holes and joints where arrows could still penetrate, meaning that even if the armour was proof against nearly all arrows, being shot at by thousands of longbowmen would have been an uncomfortable experience, physically and mentally. One contemporary French account described the barrage at Agincourt (against French knights wearing plate armour) as a "terrifying hail of arrow shot".
Full plate armour of the highest quality was also extremely expensive, only used by the most elite (and rich) soldiers, such as knights; the vast majority of soldiers were not armoured in plate from head-to-toe. Even for knights, in practice their horses tended to be less well protected, meaning that longbows could kill or wound the horses even when the arrows had little effect against the knights themselves. For example, shooting the French knights' horses from the side (where they were less well armoured) was used effectively by the English longbowmen to help win the Battle of Poitiers.
[edit] Shooting rate
A typical military longbow archer would be provided with between 60 and 72 arrows at the time of battle. Most archers would not loose arrows at maximum rate, as it would exhaust even the most experienced man. "With the heaviest bows (a modern warbow archer) does not like to try for more than six a minute."[24] Not only are the arms and shoulder muscles tired from the exertion, but the fingers holding the bowstring become strained; therefore, actual rates of shooting in combat would vary considerably. Ranged volleys at the beginning of the battle would differ markedly from the closer, aimed shots as the battle progressed and the enemy neared. Arrows were not unlimited, so archers and their commanders took every effort to ration their use to the situation at hand.
Nonetheless, resupply during battle was available. Young boys were often employed to run additional arrows to longbow archers while in their positions on the battlefield.[25] "The longbow was the machine gun of the Middle Ages: accurate, deadly, possessed of a long range and rapid rate of fire, the flight of its missiles was likened to a storm."[2] This rate was much higher than that of its Western European projectile rival on the battlefield, the crossbow. It was also much higher than the standard early firearms (although the lower training requirements and greater penetration of firearms eventually led to the longbow falling into disuse).
But I'd say if 100 of us lined up and fired solids you'd be pretty quickly diving for cover at 150 meters. 
1% chance of hitting you means pretty good chance you'd get hit.
