science

Merville SM.31

Merville SM.31 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 Merville SM.31 rather than just read about it. In short: The Merville SM.31 is a French high performance glider with a laminar flow wing, first flown in 1960. Only one was built.

Key takeaways

Merville SM.31 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Merville SM.31 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Merville SM.31 from memory before moving on to harder problems.

Reference excerpt

The Merville SM.31 is a French high performance glider with a laminar flow wing, first flown in 1960. Only one was built.

Design and development In the 1960s, André Merville was president of the Boulogne- based company Helice G. Merville, which had been the chief supplier of wooden propellers for French aircraft since the end of World War I. He sought to broaden the firm's product range by producing both light aircraft and gliders. The SM.31 high-performance sailplane was a development of their S.30 (sometimes written SM.30). It is a wood-framed aircraft, covered with a mixture of plywood and fabric. Its wing was built around a single spar with ply covering from the spar around the leading edge and fabric aft. The smooth ply skin covers just over half the chord, matching the approximate distance over which the ideal NACA airfoil 654421 maintains laminar flow; the rest is fabric-covered, though the covering of the plain ailerons is a ply and fabric mixture. In plan the wing has a rectangular centre section reaching out to about 60% of the span. Its square tipped outer sections have a swept leading edge, giving them a 6° sweep at quarter chord and a taper ratio of 65%. The ailerons are each in two parts, operating differentially and occupying about 63% of the span; the rest of the trailing edge is filled with lift-increasing Fowler flaps. There are Schempp-Hirth type air brakes on the inner section at 57% chord. The wings are shoulder mounted with a dihedral of 2.5°. The fuselage of the SM.31 is ply covered over wooden frames and stringers. In section it is ovoid, deep and narrow in the single-seat cockpit area ahead of the wings. Its single-piece, blown perspex canopy occupies most of this forward region. It has a rounded profile which curves upwards into the upper fuselage line just ahead of the wing and is side opening. Aft, the fuselage tapers slowly to the tail, where the straight tapered tailplane and elevators are mounted on top. The fin is faired into the fuselage at its root but elsewhere the vertical tail is straight tapered and flat topped. The rudder, hinged behind the elevator trailing edge and extending down to the keel, is not balanced. All the fixed tail surfaces are ply covered, with fabric covered control surfaces. The SM.31 lands on a semi-recessed, unsprung monowheel, fitted with brakes and assisted by a fixed skid which stretches from nose the under the wing trailing edge together with a tail bumper protecting the rudder. The SM.31's first flight was made on 11 January 1960. The sole example still exists, though neither airworthy nor on display. Whether it is F-CCHN in the Ailes Ancienne collection in Toulouse or F-CBYK at the Musée Régional de l'Air at Angers is not certain; one is probably the SM.30 and the other the SM.31.

Specifications Data from The World's Sailplanes II (1963) p.84-5General characteristics Crew: One Length: 8.10 m (26 ft 7 in) Wingspan: 18.06 m (59 ft 3 in) Height: 1.80 m (5 ft 11 in) over tail Wing area: 18.0 m2 (194 sq ft) Aspect ratio: 18 Airfoil: NACA airfoil 654421 at root, 643618 at tip Empty weight: 360 kg (794 lb) equipped Max takeoff weight: 460 kg (1,014 lb) Maximum wing loading: 25.5 kg/m2 (5.24 lb/sqft) Performance

Maximum speed: 220 km/h (140 mph, 120 kn) placard, smooth air Maximimum speed: 180 km/h (112 mph) placard, rough air Aerotowing speed: 100 km/h (62 mph) Winch launch speed: 100 km/h (62 mph) g limits: +5/-2 Maximum glide ratio: maximum 32.5:1, at 98 km/h (61 mph) and a weight of 440 kg (970 lb) Rate of sink: 0.78 m/s (154 ft/min) minimum, at 80 km/h (50 mph) and a weight of 440 kg (970 lb), with no flaps

References

Worked examples

Example 1 — a first encounter with Merville SM.31

Start with the simplest possible case. Write down what Merville SM.31 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 Merville SM.31 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 Merville SM.31 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 Merville SM.31

In research: Merville SM.31 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 Merville SM.31 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: Merville SM.31 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1960s French sailplanes, Aircraft first flown in 1960, Glider aircraft, so understanding it makes those chapters shorter.
In everyday life: Look for Merville SM.31 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.

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How to study Merville SM.31 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Merville SM.31 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 Merville SM.31 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Merville SM.31 in simple terms?

The Merville SM.31 is a French high performance glider with a laminar flow wing, first flown in 1960. Only one was built.

Why does Merville SM.31 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 Merville SM.31?

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 Merville SM.31.