When choosing a frame for your drone, it’s important to consider the material it’s made of, as it can greatly affect the performance and capabilities of your drone. Carbon fiber, wood, metal, plastic, and fiberglass are all common materials used in drone frames. The frame acts as the foundation that holds your drone together and enables it to fly. However, it’s important to note that there isn’t one perfect frame for all drone needs, as different frames are better suited for different purposes. In this guide, we’ll go through the factors to consider when selecting the best frame for your quadcopter drone.
A drone frame?
When building a drone, the frame is one of the most important decisions to make as it plays a crucial role in determining the size, materials, thickness, space, style, and even the geometry of your build. Whether you’re building a lightweight high-speed racer or a durable bando slayer, the frame is the foundation that holds all the other components in place. It also protects the FPV cameras, flight controllers, video transmitters, and other electronic components from damage. It’s crucial to choose a frame that meets your flying needs.
The main purpose of a frame is to protect the components inside and hold everything together. However, in racing frames, the focus is on reducing drag and limiting the effect the arms have on the thrust from the prop, which may lead to some compromise on the protection of the components. The aerodynamics of the frame do not provide lift or control surfaces like in a conventional aircraft. It’s important to remember that without motors, a drone will fall out of the sky.
Personally, I prefer a strong freestyle-focused frame that can withstand crashes without total damage. This means my quads are heavier than most race frames, but I don’t need the all-out speed. I also have a few racing frames, but my favorites are my 5-inch freestyle frames. When choosing a frame, the main factors I look for are strength, space, and a mount for an HD camera (for filming my flights). Strength is important because you will crash, and a strong frame will protect the electronics and allow for multiple crashes. Space is important because it allows for easy installation of parts and maintenance. An HD camera mount is not essential for everyone, but it’s something I value for filming my flights and capturing great footage.
Different parts of a drone frame
Drones have 3 main components: a top plate, a bottom plate, and arms. The top plate, which is typically thinner, often has holes for cable ties and battery straps and may also have a mount for a GoPro camera. The bottom plate, the thickest part of the frame, is designed to absorb crash impact and has holes to accommodate the standoffs for electronics. The arms, which may be part of the bottom plate or removable, hold the motors and sometimes the ESCs.
The size of the frame, measured as the distance between two motor mounting holes along the diagonal, determines the size of the propellers and motors that can be used and is categorized based on propeller size. The most popular frame sizes are 5-6 inches for their agility and durability, with 3-4 inches gaining popularity for their nimble handling. If flying indoors is the primary goal, it is recommended to keep the frame size under 100mm.
Types of Material
Carbon Fiber
Carbon fiber is a popular material for drone frames because of its lightweight, strength, and rigidity. However, it is not the cheapest option, can be difficult to work with, and conducts electricity, requiring additional insulation for wires. Additionally, carbon fiber can interfere with radio frequencies, requiring careful placement of antennas.
Thermoplastics
Other materials used for drone frames include plastic, such as HDPE (High-density Polyethylene), which is designed to withstand significant impacts without breaking. However, the disadvantage of plastic frames is the added weight and limited options for fitting components. The choice of hardware, such as standoffs, bolts, and screws, should also be considered. Steel and titanium are common options, with steel being less expensive but softer, while titanium is more expensive but harder and may cause issues with corrosion when mixed with other metals. Some frames also incorporate aluminum or titanium parts, which offer a high level of strength but come at a higher cost and added weight.
Different frame sizes
The size of a drone frame is typically determined by the diagonal distance between the motors, which dictates the size of propellers that can be used. The measurement for frames is in millimeters, while propellers are measured in inches. Despite this discrepancy, it is common to refer to drones by their propeller size, such as 5 inches or 6 inches.
Size range that is generally true (but not always):
| Frame Size | Prop Size | Use | Example |
|---|---|---|---|
| 280mm+ | 7 inch | Long Range | Mode 2 Shredder 7″ |
| 250mm | 6 Inch | Long Range / Freestyle / Racing | Halo Archon |
| 210mm | 5 inch | Freestyle / Racing | Impulse RC Reverb |
| 180mm | 4 inch | Freestyle / Racing | Armattan Gecko |
| 150mm | 3 inch | Freestyle / Racing | SlightClub Phuket 3″ |
| 112mm | 2 inch | Freestyle / Racing | Emax Baby Hawk R |
| 100mm- | Whoops* | Indoor / Limited outdoor | Tiny Whoop |
The most commonly used frame size in both freestyle and racing is the 210mm (or 5-inch) frame. This is because it provides a good balance between power, weight, and responsiveness. It allows for the use of 5-inch props, which offer high power and efficiency while keeping the weight of the frame low and the center of the props close to the middle. This improves the moment of inertia and allows for more force to be applied closer to the center of mass of the quad. The freestyle scene is mostly dominated by this frame size, with a few exceptions for those who use 6-inch frames.
As the frame size increases, wind resistance becomes a bigger factor to consider. 150mm (3 inch) frames are fast but can be easily blown around and have short flight times due to the need to carry smaller batteries. 4-inch frames are not as popular because they do not offer the same speed as 3-inch frames and the control is not as good as 5-inch frames.
As for 6 and 7-inch frames, they tend to face more air resistance but have bigger props that provide more power. They are often used for long-range flights and prioritize efficiency over raw power. It is important to note that while a 210mm frame can take a 5-inch prop, the clearance between the frame and the props can be very small, so it is important to check these clearances before each flight.
Shapes and Layout
The design of a quadcopter frame is determined by the arrangement of its arms. The most common layout is the 4-arm setup, which includes several variations such as H-frame, True X-frame, Hybrid X-frame, Stretched X-frame, and Square frame.
The H-frame features arms extending directly from the body, resulting in a bulkier design with limited motor placement options. The True X-frame has an equal distance between all motors, providing balanced performance. The Hybrid X-frame combines the best features of the H and X-frames, resulting in a longer body and optimal arm placement. The Stretched X-frame moves the front and rear propellers farther apart to improve high-speed handling but requires more tuning. The Square frame is an enclosed X-frame, offering increased strength but at the cost of added weight and drag.
Unibody design
A unibody frame is a design where all the arms are integrated into the bottom or top plate, as opposed to separate arms. This can come in the form of a single piece or as pair, such as having both front arms as one piece.
Why does this matter?
A unibody frame is said to be stiffer and stronger because it has fewer joints and potential weak points. However, if an arm is damaged, the entire plate may need to be replaced, which can be costly. On the other hand, separate arms can be easily replaced if damaged. This is a common practice in racing frames that prioritize low weight and are willing to replace broken arms. Some designs have clever mountings and screws to mitigate the potential issues with more joints. Ultimately, the choice between a unibody and separate arm design is a matter of personal preference.
Thickness
The strength of carbon fiber is influenced by various factors such as quality, layering, flexibility, and thickness. While it is not always the case that thicker carbon is stronger, it is important to use thicker carbon in areas of the frame that are most at risk of damage. However, thicker carbon also increases the weight of the frame. The bottom plate is often a crucial component as it withstands most impacts and holds the frame together. If using separate arms, one can opt for lightweight arms that are easily replaceable or heavier arms that can withstand more damage. As a general guideline, using 4mm carbon for the main components like the bottom plate and arms can provide good rigidity and strength. For the top plate, 3mm or 2mm is sufficient as they are usually easier to replace.
Racing Vs Freestyle
There is no definitive distinction between freestyle and racing frames as some people use freestyle frames for racing and vice versa. In general, freestyle frames are designed to be stronger and have more space for camera mounts, while racing frames prioritize weight reduction. Some pilots use both types of frames, with a dedicated race frame for speed and response, and a freestyle frame for flow and maneuverability. For beginners, it may be beneficial to start with a freestyle frame as they are typically easier to repair and can withstand more crashes.
Battery Location
The placement of the battery can greatly affect the handling of a drone, as it is a significant portion of the craft’s weight. The goal is to position it as close to the center of gravity as possible. The two common options are to mount it on top or underneath the frame. Freestyle frames often have a top-mount battery that is inline with the frame, offering protection during crashes but not optimal for performance. Racing frames typically use a bottom-mount battery, which improves cornering but increases the risk of damage in crash landings. Additionally, some frames incorporate a mid-mount battery that evenly distributes weight across the frame but requires a specific frame design to prevent interference with the propellers.
Other Considerations
The placement and angle of the FPV camera is crucial for a good line of sight, as it is what you use to navigate your drone. It is common for some propellers to be in view, especially on stretched X-frames, but the camera should not obstruct most of your view. A range of angles is also important for optimal performance, as the camera angle can greatly affect your flying experience. If the angle is too low, you may end up looking at the ground more often than where you are going, and if it’s too high, you may go too fast everywhere. If you’re just starting out, a tilt angle of 25 to 30 degrees is a good starting point. Some pilots use 60 degree tilt angles, but it is not recommended for beginners. Camera protection is a matter of personal preference, as some pilots prefer to hang their camera out the front with no protection for the best view and extreme angles, while others prefer to keep it slightly more protected inside the frame, which may limit the angles but decrease the likelihood of camera damage in a crash.
When selecting a frame for your drone, it’s important to take into account the size of your camera. There are three main sizes of the camera to consider:
- Standard size: 28mm wide, often referred to as Hs1177 size cameras
- Mini size: 21.8mm wide, but often come with brackets that allow them to fit into standard mounts
- Micro size: 19mm wide, Some come with upsizing mounts but most don’t
Make sure that your chosen frame can accommodate your camera to ensure proper fit and function.
HD Camera Option
Most freestyle drone frames come equipped with a built-in mount for attaching a GoPro or other high-definition camera, allowing for the recording of high-resolution footage. Some frames also have space for a 3D-printed mount. While there are also mounts specifically designed for racing frames, they are not always the main focus.
Personally, I prefer to use 3D-printed mounts as they allow me to secure my GoPro as close to the frame as possible to prevent the loss of both the camera and the footage.
Another important aspect to consider is protection for the motors. Damaging motors can be a major inconvenience and often means the end of a flying session. To protect the motors, many frames have the ends of the frame arms extending past the bottom of the motor. This way, the frame takes the impact instead of the motor. Some people also use 3D-printed bumpers for added protection, but this can add weight to the drone.
Spare Parts
Having a reliable source for spare parts is crucial for maintaining your drone’s airworthiness. Having multiple arms on hand, for example, can mean the difference between a frustrating crash ending your flying day and being able to quickly replace a damaged arm and continue flying. However, if your frame has a unique design and is hard to find replacement parts for, it can lead to extended downtime.
For those with a unibody design, the cost of purchasing a spare bottom plate might not be worth it, therefore, it is best to be prepared for possible downtime in this case. Other parts such as stand-offs are usually readily available and often come included in the original packaging.
Warranty, etc.
Warranty coverage is a major factor for me when choosing a drone frame. Some manufacturers offer limited or unlimited warranties on their products, with specific terms and conditions outlined on their websites. This means that if you crash and damage a component like a bottom plate or arm, you can claim it under warranty and receive a replacement at no additional cost, with the exception of shipping fees. This greatly reduces the risk for me, as I know that I have the option to receive a replacement part without incurring additional costs. I have used this on multiple occasions and it has saved me money in the long run. In my opinion, Armattan offers one of the best warranties in the market. As long as you follow the rules, they will ensure that you can keep flying. Additionally, having a spare arm on hand means you can quickly replace a damaged one without having to wait for the replacement to arrive.