KS3 Edexcel Engineering: Case Study Practical Drills | KS3 Edexcel工程：案例分析实战演练

📚 KS3 Edexcel Engineering: Case Study Practical Drills | KS3 Edexcel工程：案例分析实战演练

Case studies are a core part of the KS3 Edexcel Engineering curriculum. They help you apply theoretical knowledge to real-world problems and develop essential design and problem-solving skills. In this article, we will work through a complete practical case study: designing and building a model wind turbine that can lift a small weight. Follow each stage carefully to understand how engineers approach a brief from start to finish.

案例研究是KS3 Edexcel工程课程的核心部分。它们帮助你应用理论知识解决实际问题，培养基本的设计和问题解决技能。在本文中，我们将完整演练一个实践案例：设计并制作一个能提起小重物的风力涡轮机模型。认真跟随每个阶段，理解工程师如何处理一份简报从开始到结束。

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1. Understanding the Design Brief | 理解设计简报

The first step in any engineering project is to read and interpret the design brief. Our task is to create a functional wind turbine model using a small DC motor as a generator. The turbine must lift a 5 g weight by at least 10 cm when exposed to a desk fan at a fixed distance. Constraints include limited materials and a strict timeline of three double lessons.

任何工程项目的首要步骤是阅读并解读设计简报。我们的任务是使用一个小的直流电机作为发电机制作出一个能工作的风力涡轮机模型。该涡轮机必须在受到固定距离的桌面风扇吹风时，将一个5克的重物提升至少10厘米。限制条件包括有限的材料和严格的三节连堂课时间。

The brief also specifies success criteria: the turbine should start rotating at low wind speed, the structure must be stable, and the electrical output should be measurable across a load. Safety requirements include shielding moving parts and ensuring all joints are secure.

该简报还指定了成功标准：涡轮机应在低风速下开始旋转，结构必须稳定，并且电力输出应能在负载上测量。安全要求包括防护运动部件并确保所有连接牢固。

A clear understanding of the brief helps you define the problem: ‘How can we convert wind energy into mechanical work using simple materials?’ This question will guide all later stages.

清晰理解简报有助于你定义问题：‘我们如何利用简单材料将风能转化为机械功？’这个问题将指导后续所有阶段。

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2. Research and Investigation | 研究调查

Before designing, engineers gather information. We researched types of wind turbines: horizontal-axis (HAWT) and vertical-axis (VAWT). HAWTs are more common and efficient for steady wind, but VAWTs can catch wind from any direction. For a desk fan test, a HAWT with three or four blades is often the most practical choice.

在设计之前，工程师收集信息。我们研究了风力涡轮机的类型：水平轴（HAWT）和垂直轴（VAWT）。HAWT更常见且在稳定风况下效率更高，但VAWT可以从任何方向捕捉风。对于桌面风扇测试，三叶或四叶的HAWT通常是最实用的选择。

We also investigated blade materials. Balsa wood is light and easy to cut, but it can snap. Corrugated plastic is durable and flexible, while stiff card is cheap and readily available. The blade shape matters: curved aerofoil sections generate lift, but flat blades at an angle (pitch) can also work on a small scale. A pitch angle between 15° and 25° is a good starting range.

我们还调查了叶片材料。轻木轻且易切割，但可能折断。瓦楞塑料耐用且柔韧，而硬卡纸便宜易得。叶片形状很关键：弯曲的翼型截面能产生升力，但带角度（桨距）的平板在小比例下也能工作。桨距角在15°到25°之间是一个好的起始范围。

Another key area was the electrical system. A small DC motor acts as a generator when its shaft is spun. The output voltage depends on rotational speed and the motor’s internal construction. We learned that motors with lower rated RPM/V (e.g., 12 V at 200 rpm) produce more voltage at low speeds. Connecting the motor terminals to an LED or a small winch mechanism converts electrical energy back into light or mechanical work.

另一个关键领域是电力系统。直流电机在轴被旋转时充当发电机。输出电压取决于转速和电机的内部结构。我们了解到额定转速较低的电机（例如12 V在200 rpm时）在低速下能产生更高的电压。将电机端子连接到LED或小型绞盘机构可将电能转换回光或机械功。

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3. Generating Design Ideas | 生成设计想法

With research complete, we sketched three initial concepts. Concept A used a three-blade HAWT with balsa blades and a cardboard tower. Concept B was a four-blade VAWT made from a plastic bottle cut into curved sections. Concept C combined a two-blade HAWT with a gear system to increase winch torque.

研究完成后，我们勾勒出三个初步概念。概念A使用三叶水平轴涡轮机，轻木叶片和卡纸塔架。概念B是一个四叶垂直轴涡轮机，由塑料瓶切割成弯曲截面制成。概念C结合了双叶水平轴涡轮机和齿轮系统以增加绞盘扭矩。

Each idea was evaluated against the specification. VAWT (Concept B) had lower starting torque and was harder to mount a winch on. Concept C’s gears added friction and complexity. Concept A was the simplest, met the brief, and allowed easy blade changes. We therefore selected Concept A for further development.

每个想法都根据规范进行评估。VAWT（概念B）的起动扭矩较低，且难以安装绞盘。概念C的齿轮增加了摩擦和复杂性。概念A最简单，符合简报要求，并允许轻松更换叶片。因此我们选择概念A进行进一步开发。

We annotated our chosen sketch with dimensions: blades 15 cm long, tower 30 cm high, base 20 cm × 20 cm. The motor was to be fixed at the top of the tower, with the winch drum directly mounted on the motor shaft. A cotton thread would wrap around the drum and lift the weight.

我们给选定的草图标注了尺寸：叶片长15 cm，塔架高30 cm，底座20 cm × 20 cm。电机将固定在塔架顶端，绞盘鼓轮直接安装在电机轴上。棉线缠绕鼓轮并提升重物。

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4. Developing a Detailed Design | 开发详细设计

Detailed design requires accurate drawings and material lists. We produced a scaled orthographic drawing of the turbine, showing front and side views. The front view indicated the blade hub made from a cork disk with three evenly spaced slots at 120° intervals. The side view showed the tower as a rolled card tube with triangular base supports (gussets).

详细设计需要精确的图纸和材料清单。我们制作了涡轮机的比例正投影图，展示前视图和侧视图。前视图显示由软木盘制成的轮毂，带有三个均匀间隔120°的插槽。侧视图显示塔架为一个卷卡纸管，带有三角基座支撑（角撑板）。

We calculated the winch drum diameter needed to lift 10 cm with about 20 turns of the motor shaft. If drum circumference = π × d, and 20 turns raise the weight by 20 × circumference, we needed circumference ≈ 0.5 cm, so d ≈ 0.16 cm. That was too thin to attach the thread, so we decided to use a 1 cm diameter drum with a gear ratio of 1:5 (pedal-powered via a small rubber band). However, to keep it simple, we accepted that the motor might need many rotations, and we would measure lift height over a fixed test duration.

我们计算了将重物提升10 cm所需的绞盘鼓轮直径，假定电机轴转20圈。如果鼓轮周长=π×d，20圈提升的高度=20×周长，我们需要周长≈0.5 cm，所以d≈0.16 cm。这太细了，无法固定棉线，因此我们决定使用直径1 cm的鼓轮，并通过橡皮筋实现1:5的齿轮比。但为了简化，我们接受电机可能需要许多旋转，并将在固定测试时长内测量提升高度。

A components list was prepared: DC motor 3–6 V, cork disk, three balsa strips (15 cm × 2 cm × 0.5 cm), card tube, stiff card base, cotton thread, 5 g weight, hot glue, and masking tape. We made sure all materials were available and cost-effective.

我们准备了部件清单：DC电机3–6 V，软木盘，三条轻木片（15 cm × 2 cm × 0.5 cm），卡纸管，硬卡纸底座，棉线，5 g重物，热熔胶和遮盖胶带。我们确保所有材料均可获得且具有成本效益。

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5. Planning for Manufacture | 制定制造计划

A clear sequence of making reduces waste and mistakes. We wrote a step-by-step plan: (1) Cut cardboard base and mark motor position; (2) Roll and glue card tube for tower; (3) Attach tower to base with triangular gussets; (4) Solder or tape wires to motor terminals; (5) Fix motor to tower top using tape and hot glue; (6) Cut cork hub and sand edges; (7) Cut three slots in hub and insert balsa blades at 20° pitch; (8) Mount hub on motor shaft; (9) Attach cotton thread to shaft drum and tie weight; (10) Add safety guard around blades.

清晰的制作顺序能减少浪费和错误。我们写下了分步计划：（1）剪裁卡纸底座并标记电机位置；（2）卷制并粘贴塔架的卡纸管；（3）使用三角角撑板将塔架固定到底座；（4）将导线焊接或胶带连接到电机端子；（5）用胶带和热熔胶将电机固定在塔架顶部；（6）切割软木轮毂并打磨边缘；（7）在轮毂上切割三个插槽并以20°桨距角插入轻木叶片；（8）将轮毂安装到电机轴上；（9）将棉线系在轴鼓轮上并绑上重物；（10）在叶片周围添加安全防护罩。

We identified potential safety risks: sharp edges on cut balsa, burns from glue gun, and pinching hazard from rotating blades. Control measures included wearing safety goggles, keeping fingers clear of blades during testing, and using a low-temperature glue gun with adult supervision.

我们识别了潜在的安全风险：切割轻木的锋利边缘、胶枪烫伤以及旋转叶片的夹伤危险。控制措施包括佩戴安全护目镜、在测试期间手指远离叶片，并在成人监督下使用低温胶枪。

A time chart allocated 30 minutes for cutting and assembly, 15 minutes for gluing and wiring, and 15 minutes for initial testing. This fitted within one double lesson.

时间表分配了30分钟进行切割和组装，15分钟进行粘接和接线，15分钟进行初步测试。这符合一节连堂课的时间。

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6. Manufacturing the Prototype | 制造原型

We cut the base from corrugated card to provide stiffness. The tower tube was rolled from a sheet of card and secured with masking tape. Triangular gussets were added at 90° to the base for extra stability. The motor was attached to the tower top with a bead of hot glue and reinforced by a card brace.

我们从瓦楞卡纸上切割出底座以提供刚性。塔架管由一张卡纸卷制而成，用遮盖胶带固定。在底座上以90°添加三角角撑板以增加稳定性。电机用一条热熔胶固定到塔架顶部，并通过卡纸支架加固。

For the hub, we used a 3 cm diameter cork disk. We carefully cut three slots with a craft knife, following a template to ensure equal spacing. The balsa blades were then inserted at a 20° angle, checked with a protractor, and secured with a drop of glue. Once dry, the hub was pressed onto the motor shaft. A small collar of tape stopped it from slipping.

对于轮毂，我们使用了一个直径3 cm的软木盘。我们按照模板小心地用工艺刀切割了三个插槽，确保等距分布。然后轻木叶片以20°角插入，用量角器检查，并滴入一滴胶水固定。干燥后，轮毂被压入电机轴。一小圈胶带阻止其滑落。

The winch drum was formed by wrapping masking tape around the shaft to a diameter of about 8 mm. We wound cotton thread around it ten times and attached a paperclip hook to hold the 5 g weight. A small cardboard guard was fixed in front of the blades to prevent finger contact.

绞盘鼓轮通过在轴上缠绕遮盖胶带至直径约8 mm形成。我们在其上缠绕棉线十圈，并附上一个回形针挂钩以吊住5克重物。叶片前方固定了一小片卡纸防护板以防止手指接触。

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7. Testing the Wind Turbine | 测试风力涡轮机

Testing followed a fair test protocol. We placed the turbine 30 cm away from a desk fan set to medium speed. A ruler was positioned vertically beside the weight. We timed 30 seconds and measured the height the weight was lifted. The test was repeated three times to ensure reliability.

测试遵循公平测试协议。我们将涡轮机放置在距离设置于中速的桌面风扇30 cm处。一把直尺垂直放置在重物旁边。我们计时30秒并测量重物被提升的高度。测试重复三次以确保可靠性。

Results: Trial 1 lifted the weight 8 cm; Trial 2, 10 cm; Trial 3, 9 cm. The average lift was 9 cm, just below the 10 cm target. We observed that the turbine started spinning slowly at first, then accelerated. The voltage across a multimeter connected to the motor terminals peaked at 2.8 V.

结果：试验1将重物提升了8 cm；试验2为10 cm；试验3为9 cm。平均提升高度为9 cm，略低于10 cm目标。我们观察到涡轮机起初缓慢旋转，然后加速。连接在电机端子上的万用表读出的峰值电压为2.8 V。

We also measured blade rotation speed using a tachometer app: between 180 and 220 rpm. The tower showed slight wobble at higher speeds, indicating a need for better bracing.

我们还使用转速表应用程序测量了叶片转速：180至220 rpm之间。塔架在较高速度下出现轻微晃动，表明需要更好的支撑。

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8. Evaluating Performance | 评估性能

Evaluation compares outcomes against the design brief. The turbine successfully converted wind energy into electrical energy and then into mechanical work, which met the core requirement. However, it did not consistently reach the 10 cm lift in 30 seconds. The wobble also raised stability concerns.

评估将成果与设计简报进行比较。涡轮机成功将风能转换为电能，进而转化为机械功，这满足了核心要求。然而，它并未在30秒内稳定达到10 cm提升高度。晃动也引发了稳定性担忧。

We analysed possible reasons. The 20° blade pitch might be too steep for the fan’s airflow, causing stalled lift. The tower’s card tube, while light, was not rigid enough. The winch drum diameter could be smaller to increase lifting force (mechanical advantage) although that would reduce speed, so a balance is needed. Finally, friction between the thread and guard, and air resistance on the weight string, likely reduced efficiency.

我们分析了可能的原因。20°叶片桨距可能对风扇气流而言过陡，导致失速升力。塔架的卡纸管虽然轻，但刚性不足。绞盘鼓轮直径可以更小以增加提升力（机械效益），尽管这会降低速度，因此需要平衡。最后，线与防护板之间的摩擦以及重物绳的空气阻力可能降低了效率。

We used a simple equation to understand the lifting force:

Force (N) = Torque (N·m) ÷ Drum radius (m)

. A smaller drum radius increases force for the same torque. This was recorded in our evaluation log.

我们用一个简单公式来理解提升力：

力 (N) = 扭矩 (N·m) ÷ 鼓轮半径 (m)

。相同的扭矩下，鼓轮半径越小，力越大。这已记录在我们的评估日志中。

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9. Suggesting Improvements | 提出改进建议

Based on evaluation, we proposed three key improvements. First, adjust blade pitch to 15° by sanding a shallower slot angle. Second, reinforce the tower by inserting a wooden dowel inside the card tube or using a thicker tube from a kitchen roll. Third, replace the tape drum with a small plastic pulley from a toy kit to reduce friction and provide a consistent radius.

基于评估，我们提出了三项关键的改进建议。第一，通过打磨更浅的插槽角度将叶片桨距调至15°。第二，通过在卡纸管内插入木销或使用厨房卷纸的较厚管子来加固塔架。第三，用玩具套件中的小型塑料滑轮替换胶带鼓轮，以减少摩擦并提供一致的半径。

We also suggested adding a tail vane to keep the turbine facing into the wind, as side gusts made the turbine yaw and lose power. This would require a swivel base, which could be achieved with a drinking straw pivot. An iterative design cycle would then test these modifications and compare new results with original data.

我们还建议添加尾舵使涡轮机保持迎风，因为侧风使涡轮机偏航并损失功率。这需要一个旋转底座，可通过吸管枢轴实现。然后迭代设计循环将测试这些修改，并将新结果与原始数据进行比较。

The improvement process shows that engineering is never finished after the first prototype. Continuous testing and refinement lead to better solutions.

改进过程表明，工程绝不会在第一个原型后就结束。持续测试和完善会带来更好的解决方案。

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10. Applying the Engineering Process | 应用工程流程

This case study has taken you through the full engineering cycle: defining the problem, researching, generating and developing ideas, planning, making, testing, evaluating, and improving. These steps mirror the Edexcel KS3 assessment objectives and help you tackle any design and make task systematically.

此案例分析带你走完了完整的工程周期：定义问题、研究、生成和发展想法、计划、制作、测试、评估以及改进。这些步骤反映了Edexcel KS3的评估目标，帮助你系统地处理任何设计与制作任务。

Remember to document every stage in your portfolio. Use labelled sketches, photographs of your prototype, test data tables, and evaluation notes. Clear annotation of your design decisions shows you understand why and how you developed your product.

记住在你的作品集中记录每个阶段。使用带标签的草图、原型照片、测试数据表和评估笔记。清晰标注你的设计决策，表明你理解为什么以及如何开发你的产品。

When facing your own case study, think about the principles we applied: fair testing with repeated trials, using measurement instruments accurately, calculating means, and identifying variables (independent: blade pitch; dependent: lift height; control: fan speed, distance, weight). This scientific approach strengthens your engineering analysis.

当面对你自己的案例研究时，想一想我们应用的原则：进行重复试验的公平测试、准确使用测量仪器、计算平均值，并识别变量（自变量：叶片桨距；因变量：提升高度；控制变量：风扇速度、距离、重物质量）。这种科学方法增强了你的工程分析能力。

Lastly, always reflect on sustainability. Can any materials be replaced with recycled alternatives? Could the turbine design be scaled up for a school energy project? Such questions show you are thinking like a responsible engineer.

最后，始终反思可持续性。是否有材料可以被回收替代品取代？涡轮机设计能否扩展到学校能源项目？此类问题表明你像一名负责任的工程师一样思考。

Published by TutorHao | Engineering Revision Series | aleveler.com

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