Longbow's Fps: Unlocking The Power

Longbows are known for their relatively narrow limbs and D-shaped cross-section, measuring four to six feet. The speed of a longbow depends on several factors, including the draw weight, length, materials, and arrows used. Generally, longbows can produce speeds of 130-180 feet per second (fps) with 25-70-pound draw weights. However, a 120-pound longbow is likely to be towards the higher end of this speed range.

A 120-pound longbow's FPS range (130-180 FPS)

A 120-pound longbow is a powerful weapon, capable of shooting arrows with impressive speed and force. In terms of feet per second (FPS), a 120-pound longbow typically falls within the range of 130-180 FPS. This range can be influenced by various factors, including draw weight, length, materials used, and the type of arrows.

The speed of a longbow is an important consideration for archers, as it determines the effectiveness of the weapon. While a higher FPS generally indicates a better-quality bow, it is not the only factor that contributes to a successful shot. Balance and stability, for instance, are crucial elements that can impact the accuracy of the archer.

The draw weight of a longbow directly influences its speed. A simple way to estimate the FPS of a longbow is to add 100 to the draw weight. For example, a 40-pound longbow will have an arrow speed of roughly 140 FPS. This method can be useful when trying to determine the speed of your bow without using specialised equipment.

Longbows with higher draw weights, such as the 120-pound variety, will naturally shoot arrows at a faster speed. However, it is important to note that the speed of the arrow is just one factor in the overall performance of the bow. The materials used in the construction of the longbow, as well as the length of the bow and the type of arrows, can also impact its speed.

The design and construction of a longbow play a significant role in its performance. Longbows are known for their relatively narrow limbs and D-shaped cross-section, typically measuring four to six feet in length. The length of the bow allows for a longer draw, which can contribute to increased speed and power. However, a longer bow can also be more challenging to handle and manoeuvre, especially in tight spaces or when hunting in areas with dense foliage.

The materials used in the construction of the longbow can also impact its speed and performance. Traditional longbows were often crafted from a single piece of wood, such as yew, oak, or elm. Yew, in particular, has been prized for its use in longbows since the 1600s due to its light-coloured sapwood and high-compressive-strength heartwood. Modern longbows may also incorporate composite materials, such as fiberglass, which can increase the speed and durability of the bow.

In summary, a 120-pound longbow is a powerful weapon with an FPS range of 130-180. This speed is influenced by various factors, including draw weight, length, materials, and arrows used. While speed is important, it is not the only factor that contributes to a successful shot. Archers must also consider the balance, stability, and overall design of the longbow to ensure accuracy and effectiveness in their craft.

Factors affecting FPS (draw weight, length, materials, arrows)

Several factors influence the FPS (feet per second) of a longbow, including draw weight, length, materials, and arrows.

The draw weight of a longbow directly impacts its FPS. For example, a 10-pound reduction in draw weight can result in a loss of approximately 15-20 FPS. Thus, a 120-pound longbow will generally have a higher FPS than an 80-pound longbow.

The length of the longbow and the draw length also affect its FPS. A longer bow allows for a longer draw, which can increase the FPS. Additionally, for every 1" reduction in draw length, there is a corresponding loss of around 10 FPS.

The materials used in the construction of the longbow can also impact its FPS. For instance, yew is considered the top-tier wood for longbows due to its tensile and compressive strength. In contrast, bamboo is a more affordable option but may result in a slight loss of quality with frequent use.

Finally, the choice of arrows can influence the FPS of a longbow. Heavier arrows tend to reduce the speed of the bow. For every extra 5 grains of arrow weight, the bow's speed can decrease by approximately 1.5 FPS.

While these factors play a significant role in determining the FPS of a 120-pound longbow, it's important to note that the actual FPS may vary depending on various other factors and testing conditions.

Estimating FPS without a chronograph (add 100 to the draw weight)

To estimate the feet per second (FPS) of a 120-pound longbow without a chronograph, you can use the following methods:

Add 100 Method

One way to estimate arrow speed is to simply add 100 to the draw weight of the bow. For example, if your bow has a draw weight of 120 pounds, you can estimate that the arrow speed will be roughly 220 FPS. This method assumes that you are using the typical draw length and arrow weight for your bow.

Arrow Drop Method

Another way to estimate arrow speed without a chronograph is by comparing the arrow drop at two different distances. Here are the steps to do this:

• Shoot a group of arrows from a distance of 20 yards, using the appropriate pin setting for that distance. Focus on maintaining good form and accurate pin placement.
• Mark the centre of the group of arrows as a reference point.
• Move back to a distance of 40 yards and shoot another group of arrows at the same reference point, using the same pin setting as before (for 20 yards).
• Mark the centre of this new group of arrows.
• Measure the distance, in inches, between the centres of the two groups of arrows.
• Use this distance to estimate the arrow speed by comparing it to a chart or using an online calculator.

Online Calculators

You can also use online calculators to estimate arrow speed without a chronograph. These calculators will require you to input various parameters such as draw length, draw weight, arrow weight, and any additional weight on the bowstring. By adjusting these values, you can get a rough estimate of your arrow's speed.

It is important to note that these methods provide estimates and may not be as accurate as using a chronograph. Additionally, factors such as string weight, string length, string material, weather conditions, and arrow weight can also impact arrow speed.

FPS for hunting (150+ FPS)

For hunting, archers are happy with a longbow speed of 150 FPS (for self bows) and 165-180 FPS (for fiberglass or advanced materials). A heavy arrow and mid-150s FPS is enough to kill a deer. Most states use a 35-pound minimum because experience shows that to be the minimum to get the job done. A 45-pound compound is plenty of oomph to kill a deer.

The speed of a longbow depends on the draw weight, length, materials, and arrows used. A chronograph can be used to test the speed of a longbow. If you don't have a chronograph, you can add 100 to the draw weight of the bow to get the expected speed of the arrow. For example, if your bow has a draw weight of 40 pounds, its arrow speed is roughly 140 FPS.

The speed of a bow isn't the only factor that determines its quality. Balance and stability are also important. A positive result on a speed test means a bow is well-constructed and designed. A negative result can mean poor construction and design, but it doesn't necessarily mean the bow is defective.

Modern compound bows have an advertised speed of between 300 and 340 FPS. However, this speed is only achievable at point-blank range. The actual speed of the bow will be lower once the arrow reaches the target.

Draw weight and FPS (10 lbs less in draw weight = 15-20 FPS less)

The speed of a longbow depends on several factors, including the draw weight, length, materials, and arrows used. For every 10 lbs of reduction in draw weight, you can expect to lose around 15-20 FPS. This means that a 120-pound longbow will shoot at a higher speed than a 110-pound longbow, assuming all other factors remain constant.

For example, let's consider a longbow with a draw weight of 120 lbs. According to the formula provided by the International Bowhunting Organization (IBO), the arrow speed can be calculated as follows:

• IBO speed = 300 FPS (for a draw weight of 70 lbs)
• For every 10 lbs of reduction in draw weight, subtract 15-20 FPS from the IBO value.
• So, for a 120-pound longbow, the calculation would be: 300 FPS - (120 - 70) 15 = 210 FPS

It's important to note that the above calculation assumes a draw length of 30 inches and an arrow weight of 350 grains, which are the standard testing conditions defined by the IBO. Deviations from these parameters will also impact the arrow speed.

Additionally, the speed of a longbow can vary depending on its design and materials. Aggressive longbows can reach speeds of up to 180 FPS, while slower bows typically achieve speeds above 140 FPS. The construction and design of the bow also play a role in its performance, with well-constructed bows exhibiting higher speeds.

In summary, when considering the impact of draw weight on FPS, a general rule of thumb is that for every 10 lbs of reduction in draw weight, you can expect a decrease of approximately 15-20 FPS. This relationship is not linear, and other factors, such as draw length, arrow weight, and accessories, also come into play.

Frequently asked questions