science

Häfeli DH-1

Häfeli DH-1 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Häfeli DH-1 rather than just read about it. In short: The Häfeli DH-1 was a 1910s Swiss two-seat reconnaissance aircraft, built by the aircraft department of the Federal Construction Works (Eidgenoessische Konstruktionswerkstaette, K+W) at Thun, Switzerland. Development and design In 1915 K + W set up their aircraft department and employed August Haefeli as chief engineer.

Key takeaways

Häfeli DH-1 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Häfeli DH-1 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Häfeli DH-1 from memory before moving on to harder problems.

Reference excerpt

Development and design In 1915 K + W set up their aircraft department and employed August Haefeli as chief engineer. Häfeli had previously designed the AGO C.I and AGO C.II, German reconnaissance biplanes. His first design was the Häfeli DH-1, similar in concept to his designs for AGO Flugzeugwerke. The DH-1 was a three-bay biplane of wood and fabric construction, it had a fuselage pod with tandem seating for the two-man crew and twin booms mounting the tail. The DH-1 was powered by an Argus As II engine built under licence by Buhler Brothers Limited. Six aircraft were built.

Operational history Six DH-1s were built during 1916 but within a year three had been destroyed in accidents. The survivors were withdrawn from service in 1919 and scrapped.

Operators Switzerland Swiss Air Force

Specifications (DH-1) Data from The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985)General characteristics Crew: 2 Length: 8.82 m (28 ft 11 in) Wingspan: 12.8 m (42 ft 0 in) Height: 3 m (9 ft 10 in) Wing area: 38 m2 (410 sq ft) Empty weight: 750 kg (1,653 lb) Gross weight: 1,125 kg (2,480 lb) Powerplant: 1 × Argus As II six-cylinder in-line water-cooled piston engine, 89 kW (120 hp) Propellers: 2-bladed wooden fixed-pitch pusher propeller Performance

Maximum speed: 126 km/h (78 mph, 68 kn) Range: 250 km (160 mi, 130 nmi) Service ceiling: 9,840 m (32,280 ft) Armament

Guns: 1x 7.45 mm (0.293 in) MG 94 machine-gun

References

External links

ETH-Bibliothek Zürich, Bildarchiv. Häfeli DH-1 (M I) No 243 with Argus As II engine, viewer Das Virtuelle Luftfahrtmuseum: K+W DH 1

Illustrations

Worked examples

Example 1 — a first encounter with Häfeli DH-1

Start with the simplest possible case. Write down what Häfeli DH-1 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Häfeli DH-1 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Häfeli DH-1 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Häfeli DH-1

In research: Häfeli DH-1 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Häfeli DH-1 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Häfeli DH-1 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1910s Swiss military reconnaissance aircraft, Aircraft first flown in 1916, Biplanes, so understanding it makes those chapters shorter.
In everyday life: Look for Häfeli DH-1 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Häfeli DH-1” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Häfeli DH-1 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Häfeli DH-1 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Häfeli DH-1 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Häfeli DH-1 in simple terms?

The Häfeli DH-1 was a 1910s Swiss two-seat reconnaissance aircraft, built by the aircraft department of the Federal Construction Works (Eidgenoessische Konstruktionswerkstaette, K+W) at Thun, Switzerland. Development and design In 1915 K + W set up their aircraft department and employed August Haef…

Why does Häfeli DH-1 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Häfeli DH-1?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Häfeli DH-1.