飞行器选材料，只有一句话：减重不减强度。
一句"减重 30%"放在家电上叫加分项，放在飞行器上叫刚需——重量直接换成续航、载荷和航时。
无人机和 eVTOL 里能换塑料件的位置很多：机臂、机身框架、云台支架、桨叶、桨夹、电机座、电池仓、电控外壳。
但它们不是一套材料能打下来的。同一个飞行器上，机臂和桨叶的选料逻辑，几乎是反的。
开篇先讲个现场
年初一个做农业无人机的客户寄来一箱“残骸”：炸机之后收拢的机臂断口、开裂的桨夹、磨白的起落架。他的问题很具体：这箱零件里，哪些是料的问题，哪些是设计的问题？我们逐件看下来，结论比他预想的有意思——机臂断裂是典型的冲击失效，料没错但壁厚取保守了；桨夹开裂是材料没问题、装配预紧过大；起落架磨损是选料档次低了。
这个箱子几乎装全了无人机用尼龙的三类场景：受冲击的结构件、受预紧的连接件、受摩擦的运动件。三类件的选料逻辑完全不同，但很多团队用一张料单打天下，出事之后又笼统地怀疑料。
这篇就按这个逻辑展开。先算一笔减重与续航的材料账，说明为什么低空对塑料的需求比地面设备迫切得多；然后三个主战场分别拆：机臂框架的玻纤碳纤之争、桨叶这块最难啃的骨头、电池仓电控外壳的合规优先。
再给四个坑和一条硬边界——哪些件还轮不到塑料。飞控和结构的读者各取所需，建议从第一节那笔账读起，账算清楚了，后面的选料决策才有锚。
一、先算一笔材料账
行业里做飞行器件，成本通常只占考虑的一半，另一半是重量。
密度：铝合金约 2.7 g/cm³，玻纤增强尼龙约 1.3-1.4 g/cm³，碳纤增强尼龙约 1.2-1.3 g/cm³- 比强度：纤维增强后，尼龙的比强度可以接近甚至超过部分铝合金- 成型：注塑几十秒一件，能撑起批产
公开资料里有一组常被引用的对比——某 7 公斤级农用无人机的机臂，6061 铝合金方案单支约 74 克，换成注塑的长碳纤尼龙机臂后约 43 克，减重约 42%，实测喷洒飞行后结构完好。
这类数据的价值不在于数字本身，而在于说明一件事：机臂这种"承力但非精密"的件，塑料化的门槛已经过了。
但门槛过了，不等于每个件都过了。往下看三个部位。
二、三个主战场，三套逻辑
| 部位 | 主流基材方向 | 纤维类型 | 关键指标 |
|---|
| 机臂 / 机身框架 | PA6、PA66 | 短碳纤 / 长碳纤 | 弯曲模量、抗疲劳、抗冲击 |
| 桨叶 / 桨座 | PA66、PA12 | 长碳纤为主 | 疲劳极限、刚性、尺寸稳定 |
| 云台支架 / 电机座 | PA6-CF、PA66-CF | 短碳纤 | 刚性、耐温、抗振 |
| 电池仓 / 电控外壳 | 阻燃 PA6、PA66 | 玻纤 + 无卤阻燃 | UL94 V0、绝缘、尺寸稳定 |
| 起落架 / 缓冲垫 | 增韧 PA6、TPAE | — | 低温韧性、回弹 |
同一张表放一起看，能看出三条分界：
机臂看"扛"，桨叶看"疲劳"，电池仓看"合规"。三个词的顺序不能换。
三、机臂和框架：玻纤还是碳纤
这是最常被问到的问题，答案取决于机型和载荷。
玻纤增强（PA6-GF30 / PA66-GF30）- 优势：成本可控、供应稳、不干扰电磁信号- 适用：消费级、农业级、常规结构件- 注意：玻纤件重量比碳纤高一些，刚性也低一档
短碳纤（PA6-CF / PA66-CF，碳纤 20-30%）- 公开资料里这类材料拉伸强度可以做到 150-220MPa 区间，弯曲模量突破 10GPa- 适用：电机支架、加强框、云台件- 注意：导电、成本高、各向异性
长碳纤（PA6-LCF / PA66-LCF / PA12-LCF）- 纤维保留长度更长，刚性和抗疲劳明显优于短纤- 公开的牌号数据里，35% 长碳纤增强 PA66 弯曲模量接近 27GPa，热变形温度可达 255℃- 适用：高刚性机臂、桨叶、承力框- 注意：注塑工艺窗口更窄，浇口和流道设计很关键
一个判断句：玻纤解决"够不够用"，碳纤解决"轻不轻"，长碳纤解决"扛不扛得住长期振动"。三档不是替代关系，是价格阶梯。
无人机件一个特殊要求：不能干扰信号
这是飞行器件和普通工业件最大的不同。
机臂和机身框架靠近天线、GPS、图传模块。金属件需要专门的布局避让，玻纤和碳纤尼龙则是非金属基体，对电磁更友好。
但要注意：碳纤维本身是导电的。 整根碳纤机臂在电磁意义上并不"透明"，靠近天线时仍需要留距离或做隔离。这一条在打样阶段就要和飞控一起确认。
四、桨叶：这是最难的一块
桨叶是飞行器的动力核心运动件，工况最苛刻：
高速旋转的离心载荷、气流冲击、户外温差、起降磕碰。
它和机臂的要求几乎相反。 机臂怕变形，桨叶更怕"翘曲和动平衡失稳"——桨叶一旦变形不均匀，振动会迅速放大。
桨叶选材看四个东西：
① 疲劳极限，不是拉伸强度。 桨叶是十万到千万次量级的交变载荷。公开资料里长碳纤 PA66 方案在 10⁷ 次循环下的疲劳强度可以做到百 MPa 量级。只报拉伸强度的资料，说明它没打算给你做桨叶。
② 刚性，决定桨尖变形。 桨尖在高转速下的挠度直接影响气动效率。这就是为什么桨叶偏爱长碳纤——短纤解决不了桨尖刚性。
③ 低吸湿。 桨叶怕的是"吸湿后螺距变了"。PA12 和 PA612 这些长碳链尼龙的平衡吸水率低，尺寸漂移更小。户外长航时机型，湿态尺寸比干态强度更重要。
④ 抗冲击。 磕碰后不能碎。增韧与增强要一起做，纯高刚性方案一磕就裂。
| 桨叶类型 | 材料方向 | 主要理由 |
|---|
| 消费级小桨 | PA6-CF / PA66 + 增韧 | 成本、批量、抗小磕碰 |
| 工业级长航时 | PA12-CF / PA12-LCF | 低吸湿、尺寸稳定、耐候 |
| 重载 / 高转速 | PA66-LCF | 高刚性 + 高疲劳极限 |
| eVTOL 旋翼连接件 | PA66-LCF / PPA-CF | 高刚性、耐温 |
（方向性建议，具体以牌号 TDS 与实测为准）
为什么 PA12 常出现在桨叶里？ 它的平衡吸水率是尼龙家族里最低的一档，尺寸对湿度不敏感。代价是刚性和耐温不如 PA66，所以要配碳纤一起用。
五、电池仓和电控外壳：这里先看合规
飞行器的电气件，选料顺序和结构件完全不同。
先看阻燃，再看绝缘，最后才看轻。
阻燃等级：无卤阻燃体系做到 UL94 V0，是电池仓和电控外壳的入场线- 耐电痕 CTI：eVTOL 向高压平台演进之后，高压连接器与电气壳体的 CTI 要求会真正卡人，这一点在选料早期就要问- 灼热丝 GWIT：安规做整机认证时，卡人的往往不是 UL94- 尺寸稳定：电池仓有安装孔位，吸湿涨缩会影响装配
这里最容易犯的错，是把结构件的思路带过来。 拿一个高玻纤、高刚性的牌号去做电控外壳，刚性够了，阻燃和绝缘可能一条都不满足。
UL94 是入场券，GWIT 和 CTI 才是分水岭。 这句在飞行器电气件上，比在任何一个行业都适用。
桨叶：材料之外还是动平衡的仗
无人机桨叶被公认为最难的一块，难在哪？不只是材料要轻、要刚性、要耐疲劳，更难的是动平衡。两片桨叶哪怕只差零点几克，高速旋转下就是持续振动，整机抖动、电机轴承早衰、航拍画面抖动全跟着来。
尼龙桨叶的注塑一致性天然比碳纤铺层好，这是它的优势位；但玻纤在件内的取向差异，会让不同批次的桨叶重心微漂，这在消费级上无感，在专业级上就是投诉。我们建议做桨叶的团队建立两个习惯：一是每批留样称重配对，按重量差配对出厂；
二是把注塑工艺参数锁死在窄区间，别让保压波动带进桨叶的密度差里。材料选对了，纪律跟上，桨叶的良率才稳得住。
六、低空用尼龙的四个坑
坑 1：拿样条数据当零件数据。 碳纤在注塑后长度会衰减，实际件的性能比样条低一截。做桨叶和机臂，必须要零件级的验证数据，不能只看 TDS。
坑 2：忽略各向异性。 碳纤件沿流动方向和垂直方向收缩差很大，长条件必然翘曲。浇口位置定了，翘曲方向几乎就定了。
坑 3：玻纤顶碳纤省钱。 在机臂上，部分工况这样降本可行；但桨叶不行——刚性差一档，振动和效率会立刻体现出来。
坑 4：户外件不做耐候。 飞行器长期暴晒淋雨，紫外线和水解是两条并行老化路径。户外用件必须配耐候体系，并且按户外耐候标准验收，不能按室内标准放行。
七、边界：这些件还轮不到塑料
| 部位 | 结论 | 原因 |
|---|
| 主旋翼轴 / 传动轴 | 不适合 | 扭矩集中、疲劳极限要求超塑料区间 |
| 高精度电机转子件 | 不适合 | 动平衡与磁路要求 |
| 高温发动机附近（燃油机型） | 不适合 | 长期高温超出尼龙稳定区间 |
| 大尺寸一体机身（>1.5m） | 需谨慎 | 注塑件尺寸与刚性受限，多为复材方案 |
| 高载荷起落架主撑 | 需谨慎 | 冲击载荷集中，需金属或复材 |
飞行器选材有一条铁律：能减重的地方大胆减，安全边界的地方一寸不让。
同一个整机上，有几处件就该是金属——这不是保守，是常识。
行业里的一条实感
碳纤尼龙的询盘，这两年明显变多。我们观察到一个很实际的现象：
客户在选碳纤料时，最容易高估的就是"碳纤含量"这个数字。
很多人上来就问"你们有没有 40%、50% 碳纤的"。含量高确实刚性高，但对飞行器件来说，真正决定成败的是碳纤在件里保留了多少长度、分布得多均匀，而不是配料单上写的那个百分比。
同一批 30% 碳纤的料，注塑工艺好和不好，件的实际刚性可以差出一大截。这个差距不会写在 TDS 上，只会写在试飞结果里。
所以我们接这类询盘，会先问的是：这个件是注塑的还是模压的？浇口打算放哪？壁厚多少？ 而不是先问你要多少个点的碳纤。
碳纤料真正的门槛在工艺，不在配料百分比。
读者追问两则
追问一：碳纤件和玻纤件怎么快速判断该用哪个？ 一个简化判据：看这个件在载荷谱里是弯矩为主还是冲击为主。弯矩为主、追求刚度减重的，碳纤值得溢价；冲击为主、要吸能要韧性的，玻纤增韧体系更扛造。
介于两者之间的，比如机臂这种既要弯又要扛炸机冲击的，主流方案是玻纤打底、关键部位局部碳纤补强，成本和性能都能交代。
追问二：农业和物流场景对材料的侧重差在哪？ 农业机的关键词是药和泥：农药介质腐蚀和泥水磨蚀，选料要加耐化体系和耐候体系，外观次之。物流机的关键词是循环和低温：起降次数按天累计，冬天高纬度作业，低温冲击和疲劳寿命是主考题。同一个平台改用途不改结构的话，材料这一层往往要重新过一遍，这是很多团队漏掉的。
最后补一条采购侧的建议：无人机行业订单波动大，供应商比场景更难选。给个三看口诀：一看牌号谱系，主打一两个牌号的小厂抗波动能力弱，谱系全的供应商才接得住你的改版节奏；二看行业案例，问要同场景的供货记录，最好能要到跑过一轮生命周期的客户；
三看检测反应速度，无人机改版快，样件检测三五天能出结果的供应商，能让你的结构迭代快一个身位。料选对只是及格线，供应跟得上才能拿满分。
炸机残骸分级排查法
无人机团队收到残骸，按三级排查，别上来就怪料。一级看断口：断口发白呈脆性放射状的是冲击超载，看设计冗余；断口平整发亮、有疲劳弧线的是交变载荷累积，看载荷谱和料档；断口有银纹和应力集中痕迹的是装配预紧过大，看拧紧规范。
二级看位置：断在取向末端的是玻纤取向吃掉了那个方向的强度，看浇口和流动设计；断在熔接线上的看合流位置有没有避开主受力方向。三级看时间：装机当天出事偏设计和装配，几十个起落后出事偏疲劳和老化。
三级排查走完，料的问题通常只剩一小部分，而这一小部分，拿着断口照片和批次记录去找供应商，比一句你们料不行有效得多。
再把保险这一层补上：无人机行业目前对塑料件还没有强制的适航认证体系，但头部厂商已经开始做企业级的材料数据库和批次追溯。这个行业正在从极客玩具走向交通工具，监管收紧是迟早的事。提前两三年把材料追溯做起来的企业，等新规落地时就是现成的合规样板；
等政策驱动再补课的企业，交的学费会比今天多好几倍。合规这件事，早做是资产，晚做是成本，行业规律向来如此。
结语
低空经济对材料的需求，说到底是把"轻"和"可靠"同时做到。
机臂按"扛"选，桨叶按"疲劳"选，电池仓按"合规"选。 三套逻辑分清，八成的选料问题自己就解决了。
剩下两成，出在工艺上——碳纤件和长玻纤件的注塑窗口比普通尼龙窄得多，浇口、流道、模温任何一个没配好，材料再好也白搭。
有些生意我们不做。
不问用途就报价的，不做。把副牌料说成正牌卖的，不做。承诺"什么工况都能用"的，不做。
When choosing materials for aircraft, there is only one sentence: reduce weight without reducing strength.
Putting '30% weight reduction' on home appliances is called a bonus feature, but putting it on aircraft is called a necessity — weight directly translates into range, payload, and flight time.
There are many parts in drones and eVTOLs where plastic components can be replaced: arms, fuselage frames, gimbal mounts, propellers, propeller clamps, motor mounts, battery compartments, and electronic control housings.
But they cannot be made from a single set of materials. On the same aircraft, the material selection logic for the arms and the blades is almost opposite.
Let's start with a live scene
At the beginning of the year, a client who makes agricultural drones sent us a box of 'wreckage': broken drone arms after a crash, cracked propeller clamps, and scuffed landing gear. His question was very specific: among these parts, which ones were material issues, and which were design issues? We examined them one by one, and the conclusions were more interesting than he expected—the arm fractures were a typical impact failure, with no material issues but the wall thickness chosen was conservative; the propeller clamp cracks were not due to material problems but excessive assembly preloading; the landing gear wear was because the material grade chosen was too low.
This box is almost fully packed with three types of scenarios for drones using nylon: structural parts subjected to impact, fastened connectors, and moving parts subjected to friction. The logic for selecting materials for the three types of parts is completely different, but many teams use a single material list for everything, and after something goes wrong, they vaguely suspect the material.
This article will unfold according to this logic. First, calculate the material balance for weight reduction and endurance, explaining why low-altitude operations require plastics much more urgently than ground equipment; then break down the three main battlefields separately: the contest between fiberglass and carbon fiber for the drone arm frames, the toughest nut to crack in the propeller blades, and the compliance priority for battery compartments and electronic control housings.
Add four more pitfalls and one hard boundary — which parts are still not up to plastic. Readers interested in flight control and structure can each take what they need. It is recommended to start reading from the accounting in the first section; once the accounts are clear, the subsequent material selection decisions will have an anchor.
1. First, calculate a materials account
In the industry of making aircraft components, cost usually only accounts for half of the consideration, the other half is weight.
Density: Aluminum alloy about 2.7 g/cm³, glass fiber reinforced nylon about 1.3-1.4 g/cm³, carbon fiber reinforced nylon about 1.2-1.3 g/cm³ - Specific strength: After fiber reinforcement, the specific strength of nylon can approach or even exceed that of some aluminum alloys - Molding: Injection molding takes tens of seconds per piece, suitable for mass production
There is a commonly cited comparison in public sources—a certain 7-kilogram-class agricultural drone's arm weighs about 74 grams per piece with a 6061 aluminum alloy design, and after switching to an injection-molded long carbon fiber nylon arm, it weighs about 43 grams, reducing the weight by approximately 42%, and the structure remained intact after actual spraying flights.
The value of this kind of data does not lie in the numbers themselves, but in illustrating one thing: for components like robot arms that 'bear force but are not precise,' the threshold for using plastic has already been surpassed.
But passing the threshold does not mean every piece has passed. Look at the three parts below.
2. Three main battlefields, three sets of logic
| Body part | Mainstream substrate direction | Fiber type | Key indicators |
|---|
| Boom / Airframe | PA6, PA66 | Short carbon fiber / Long carbon fiber | Bending modulus, fatigue resistance, impact resistance |
| Paddle / Paddle Housing | PA66, PA12 | Primarily long carbon fiber | Fatigue limit, rigidity, dimensional stability |
| Gimbal Bracket / Motor Base | PA6-CF, PA66-CF | short carbon fiber | Rigidity, temperature resistance, vibration resistance |
| Battery Compartment / Electrical Control Housing | Flame-retardant PA6, PA66 | Glass fiber Halogen-free flame retardant | UL94 V0, insulation, dimensional stability |
| Landing gear / Cushion pad | Toughened PA6, TPAE | — | Low-temperature toughness, resilience |
Looking at the same table together, three dividing lines can be seen:
Look at the arm for 'bearing', look at the blades for 'fatigue', look at the battery compartment for 'compliance'. The order of the three words cannot be changed.
3. Arm and frame: fiberglass or carbon fiber
This is the most frequently asked question, and the answer depends on the model and the load.
Glass Fiber Reinforced (PA6-GF30 / PA66-GF30) - Advantages: controllable cost, stable supply, does not interfere with electromagnetic signals - Suitable for: consumer grade, agricultural grade, conventional structural parts - Note: glass fiber parts are heavier than carbon fiber and have slightly lower rigidity
Short carbon fiber (PA6-CF / PA66-CF, 20-30% carbon fiber) - According to publicly available information, the tensile strength of this type of material can reach the range of 150-220MPa, and the flexural modulus exceeds 10GPa - Applications: motor brackets, reinforcing frames, gimbal components - Note: conductive, high cost, anisotropic
Long Carbon Fiber (PA6-LCF / PA66-LCF / PA12-LCF) - Fibers retain longer lengths, with rigidity and fatigue resistance significantly better than short fibers. - According to published grade data, 35% long carbon fiber reinforced PA66 has a flexural modulus close to 27 GPa and a heat deflection temperature up to 255℃. - Suitable for: high-rigidity arms, blades, load-bearing frames. - Note: injection molding process window is narrower, so gate and runner design is critical.
A judgment sentence: fiberglass addresses 'is it enough,' carbon fiber addresses 'is it light,' long carbon fiber addresses 'can it withstand long-term vibration.' The three tiers are not substitutes; they are a price ladder.
A special requirement for the drone: it must not interfere with signals
This is the biggest difference between aircraft components and ordinary industrial parts.
The boom and fuselage frame are close to the antenna, GPS, and image transmission module. Metal parts require special layout avoidance, while fiberglass and carbon fiber nylon are non-metallic matrices and are more electromagnetic-friendly.
But note: carbon fiber itself is conductive. The entire carbon fiber arm is not 'transparent' in an electromagnetic sense, so a distance or isolation is still needed when it is close to the antenna. This point should be confirmed with the flight controller during the prototyping stage.
4. Blades: This is the most difficult part
The blades are the core moving components of the aircraft's power system, operating under the most demanding conditions:
High-speed rotating centrifugal loads, airflow impact, outdoor temperature differences, takeoff and landing bumps.
Its requirements are almost the opposite of those for the boom. The boom fears deformation, but the blades are even more afraid of 'warping and loss of dynamic balance'—once the blades deform unevenly, vibrations will quickly amplify.
There are four things to consider when selecting paddle blades:
① Fatigue limit, not tensile strength. The blades are subjected to alternating loads on the order of hundreds of thousands to tens of millions of cycles. According to public information, the fatigue strength of long carbon fiber PA66 schemes can reach the order of hundreds of MPa at 10⁷ cycles. Data that only reports tensile strength indicates that it is not intended for making blades.
② Rigidity determines the deformation of the propeller tip. The deflection of the propeller tip at high rotational speeds directly affects aerodynamic efficiency. This is why propeller blades prefer long carbon fibers—short fibers cannot solve the rigidity of the propeller tip.
③ Low moisture absorption. The blades are afraid of 'pitch changes after absorbing moisture.' PA12 and PA612, these long-chain nylons, have low equilibrium water absorption and smaller dimensional drift. For long-endurance outdoor models, wet-state dimensions are more important than dry-state strength.
④ Impact resistance. It should not break after being bumped. Toughening and strengthening must be done together; a purely high-rigidity solution will crack on impact.
| Blade type | Material direction | Main reason |
|---|
| Consumer-grade small paddle | PA6-CF / PA66 Toughened | Cost, batch, resistance to small bumps |
| Industrial-grade long endurance | PA12-CF / PA12-LCF | Low moisture absorption, dimensionally stable, weather-resistant |
| Overload / High Speed | PA66-LCF | High rigidity High fatigue limit |
| eVTOL rotor connector | PA66-LCF / PPA-CF | High rigidity, temperature resistant |
(Directional suggestions, subject to the TDS of the grade and actual measurements)
Why does PA12 often appear in blades? Its balanced water absorption rate is the lowest in the nylon family, making its dimensions insensitive to humidity. The trade-off is that its rigidity and heat resistance are not as good as PA66, so it needs to be used together with carbon fiber.
5. Battery compartment and electronic control casing: First, look at compliance here
The electrical components of the aircraft have completely different material selection sequences and structural parts.
First look at flame retardancy, then at insulation, and finally at lightness.
Flame Retardant Level: Halogen-free flame retardant system achieves UL94 V0, which is the entry requirement for battery compartments and electrical control housings - Tracking Resistance CTI: After eVTOL evolves towards a high-voltage platform, the CTI requirements for high-voltage connectors and electrical housings will truly become critical. This should be questioned early in the material selection stage - Glow Wire GWIT: During safety certification of the whole machine, it is often GWIT rather than UL94 that becomes the bottleneck - Dimensional Stability: The battery compartment has mounting holes, and moisture absorption and dimensional changes can affect assembly
The most common mistake here is bringing in the mindset of structural components. Using a grade with high glass fiber and high rigidity for an electronic control housing may provide enough rigidity, but it might not meet fire resistance and insulation requirements at all.
UL94 is the ticket of entry, GWIT and CTI are the watershed. This sentence applies to aerospace electrical components more than to any other industry.
Blade: Apart from the material, it still relies on dynamic balance
Drone propellers are widely recognized as the most difficult part. What makes them difficult? It's not just that the material needs to be light, rigid, and fatigue-resistant; the hardest part is dynamic balancing. Even if two propeller blades differ by only a few tenths of a gram, continuous vibration will occur when spinning at high speed, causing the entire machine to shake, premature motor bearing wear, and shaky aerial footage.
The injection molding consistency of nylon blades is naturally better than that of carbon fiber layups, which is its advantage. However, differences in the orientation of glass fibers within the part can cause slight variations in the center of gravity of blades from different batches. This is imperceptible at the consumer level but can lead to complaints at the professional level. We recommend that teams making blades establish two habits: first, keep samples from each batch and pair them by weight for matching before shipment;
Second, lock the injection molding process parameters in a narrow range, and don't let the holding pressure fluctuations affect the density differences of the blades. With the right material and proper discipline, the yield rate of the blades can be kept stable.
6. Four Pitfalls of Using Nylon at Low Altitude
Pitfall 1: Using sample data as part data. Carbon fiber shrinks in length after injection molding, and the performance of the actual parts is lower than that of the samples. When making blades and arms, part-level verification data is necessary; you cannot rely solely on the TDS.
Pitfall 2: Ignoring anisotropy. Carbon fiber parts shrink very differently along the flow direction and perpendicular to it, so warping is inevitable under long conditions. Once the gate location is fixed, the warping direction is almost determined.
Pitfall 3: Saving money with fiberglass tips instead of carbon fiber. On the boom, cost reduction this way is feasible for some working conditions; but for the blades, it won't work—the rigidity drops a level, and vibration and efficiency will immediately become apparent.
Pitfall 4: Outdoor components are not made weather-resistant. Aircraft are exposed to long-term sun and rain, with ultraviolet radiation and hydrolysis being two parallel aging pathways. Outdoor components must be equipped with a weather-resistant system and accepted according to outdoor weathering standards, not released according to indoor standards.
7. Boundary: These parts are not yet for plastic.
| Part | Conclusion | Reason |
|---|
| Main Rotor Shaft / Drive Shaft | Not suitable | Torque concentration, fatigue limit requirements exceed the plastic range |
| High-precision motor rotor parts | Not suitable | Dynamic balancing and magnetic circuit requirements |
| Near high-temperature engine (fuel-powered model) | Not suitable | Long-term high temperatures exceed the stable range of nylon |
| Large integrated body (>1.5m) | Need to be cautious | The dimensions and rigidity of injection-molded parts are limited, mostly using composite material solutions. |
| High-load landing gear main strut | Need to be cautious | Impact load is concentrated, requiring metal or composite materials |
There is an iron rule in aircraft material selection: boldly reduce weight wherever possible, but not give an inch in areas concerning safety margins.
On the same machine, several parts should be metal — this is not conservatism, it's common sense.
A real feeling in the industry
Inquiries about carbon fiber nylon have obviously increased in the past two years. We have observed a very practical phenomenon:
When choosing carbon fiber materials, the number that customers are most likely to overestimate is the 'carbon fiber content'.
Many people come up and ask, 'Do you have carbon fiber with 40% or 50% content?' A higher content indeed means higher rigidity, but for aerospace components, what really determines success is how much length of the carbon fiber is retained in the part and how evenly it is distributed, not the percentage written on the ingredient list.
For the same batch of material with 30% carbon fiber, the actual rigidity of the parts can vary greatly depending on whether the injection molding process is good or not. This gap won't be listed in the TDS, it will only be reflected in the test flight results.
So when we receive this type of inquiry, the first questions we ask are: Is this part injection molded or compression molded? Where is the gate going to be? How thick is the wall? Not how many grams of carbon fiber you need.
The real barrier for carbon fiber materials lies in the process, not in the percentage of ingredients.
Two Reader Inquiries
Follow-up Question 1: How can we quickly decide whether to use a carbon fiber part or a fiberglass part? A simplified criterion: look at whether the part experiences mainly bending moments or impacts in the load spectrum. For bending-dominated loads where stiffness-to-weight ratio is important, the premium for carbon fiber is worth it; for impact-dominated loads where energy absorption and toughness are needed, a toughened fiberglass system is more robust.
For those in between, such as robotic arms that need to both bend and withstand crash impacts, the mainstream solution is to use a fiberglass base with local carbon fiber reinforcement in key areas, which can balance both cost and performance.
Follow-up Question 2: How do agriculture and logistics scenarios differ in their focus on materials? The keywords for agricultural machinery are chemicals and mud: corrosion from pesticide media and abrasion from mud and water; material selection needs chemical-resistant systems and weather-resistant systems, with appearance being secondary. The keywords for logistics machinery are cycles and low temperatures: takeoff and landing counts accumulate daily, operations in high-latitude areas during winter, with low-temperature impact and fatigue life being the main concerns. If the same platform is repurposed without changing the structure, the material aspect usually needs to be reviewed again, which is often overlooked by many teams.
Finally, one more suggestion for the procurement side: The drone industry has large order fluctuations, and suppliers are harder to choose than the applications themselves. Here's a three-step mantra: First, look at the brand series; small factories focusing on only one or two brands have weak ability to withstand fluctuations, only suppliers with a complete series can keep up with your revision pace. Second, look at industry cases; ask for supply records for the same scenario, preferably from customers who have gone through a full product lifecycle.
Third, observe the testing response speed. Drones that are quickly updated and suppliers whose sample testing can yield results in three to five days can make your structural iterations a step faster. Choosing the right materials is just the passing line; only suppliers who can keep up allow you to get a full score.
Drone Wreckage Classification and Inspection Method
When a drone team receives wreckage, they inspect it in three levels. Don’t start by blaming the material. Level one looks at the fracture: a white, brittle, radiating fracture indicates impact overload—check design redundancy; a smooth, shiny fracture with fatigue arcs indicates cumulative alternating loads—check the load spectrum and material batch; a fracture with silver streaks and stress concentration marks indicates excessive assembly pre-tightening—check tightening standards.
Level two looks at the location: if broken at the fiber orientation end, it means the fiberglass orientation has consumed the strength in that direction—check the gate and flow design; if broken along the weld line, check whether the merge location avoids the main stress direction. Level three looks at time: failures on the day of installation point to design and assembly issues; failures after dozens of takeoffs point to fatigue and aging.
After the three-level inspection, material issues usually remain only in a small portion. For this small portion, taking fracture photos and batch records to the supplier is far more effective than just saying the material is bad.
Add this layer of safety: currently, the drone industry does not have mandatory airworthiness certification for plastic parts, but leading manufacturers have started building enterprise-level material databases and batch traceability. This industry is moving from geeky toys to transportation tools, and stricter regulation is inevitable. Companies that set up material traceability two to three years in advance will have ready compliance models when new regulations are implemented;
Companies that wait for policy to force them to catch up will pay several times more in lessons learned. Compliance, if done early, is an asset; if done late, it is a cost. This has always been the规律 of the industry.
Conclusion
The requirements of low-altitude economy for materials ultimately come down to achieving both "lightweight" and "reliable."
Select arms based on "strength," blades based on "fatigue," and battery compartments based on "compliance." With these three logics clearly separated, 80% of material selection issues are solved on their own.
The remaining 20% are in the process—carbon fiber and long fiberglass parts have narrower injection molding windows than ordinary nylon. If the gate, runner, or mold temperature is not properly set, even the best material is useless.
There are some businesses we do not engage in.
We do not quote prices without asking the application. We do not sell off-brand materials as premium ones. We do not promise that a part can be used in "any working condition."
