8/13/2019 1942 - 1194

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Aircraft IdentificationFLIGHT JU N E 4TH, 1942

W H AT I S I T ?Aircraft Characteristics T hat Aid the Spotter

Classified A Simple G uide forBasic F eatures in Design

the Beginner

/ A LT H O U G H m a n y o f Flight's rea der s will be familiar/ A with the visible char acterist ic s of aircraft from the

* -^ spotter 's point of view, identificat ion is a comparat ive ly new' sc ien ce , and there wi ll inev i tab ly be a constan t s t ream of newcomers to th i s importa n t s tudy. I twas fel t , therefore, that a few notes deal ing with thefundamenta l ex terna ls o f a i rc raf t would grea t ly he lp thebeginner, be he 14-year-old Air Scout or 1914 Veteran.

No at tempt is made, in this l imited space, to cover al lthe many subdivisions into which aircraft can be classified ; th e scope of the artic le is necessarily lim ited to th ebasic differences in design, but it will give the learner-spotter a useful start .. Pro ba bly becau se i t is the mo st easi ly observed featu re,

the posi t ion of the wings in relat ion to the fuselage sect iondivides aircraft into three main gro up s: (1) low-wing, inwhich the wing is level with the underside of the fuselage ;(2) mid-wing, in which i t passes through the sides of thefuselage ; an d (3) high- wing , in which i t is level with th eto p of the fuselage. The re are, in poin t of fact , subdivisions of the. mid-w ing class accord ing to w heth er i t isnearer the bo t tom or the top , bu t we sha l l no t bo ther wi ththa t here . Pedesta l and paraso l wings are , s imi lar ly, subdivisions of the high-wing class.

tilfh wing

Mu&- fi 'Lng

l_OM Wing

The next po in t about the wings i s the angle , o r angles ,they m ake wi th the fuse lage . A few h igh-wing type s a reflat , bu t the vas t majori ty of al l thre e type s are raisedtow ards th e t ips to increase stabil i ty ; this is cal led dihedral angle and may ei ther be applied right from theroots at the fuselage or from a flat centre-sect ion as shownin the accompanying d iagram.

There is also a third class in which the centre sect ionmakes a sharp dihedral angle with the fuselage and the

rest of the wing is flat , and a fourth style in which thecent re-sec t ion makes a downward , o r anhedra l ang le wi ththe fuselage and the rest of the wing rises towards the t ipsat a dihedral angle. Th e former is cal led a gull-wing andthe la t te r an inverted gu l l, o r c ranked wing . The cr ankedwing type is found with angles of varying degree from themoderate (e.g. Miles Master) to the acute (e.g. Ju 87).

Dihedratfrcv roots

Dihedral fromflat Ccnt-c- section

Oult w Inverted Cullor csvnkof king

Seen in plan, wings fal l into six groups as i l lustratedstraight paral lel edges, at right angles to the fuselage, thewhole wing backswept on each side of the fuselage, leading-edge on ly backswept , t ra i l ing-edge swept fo rward , t aperedon bo th edges , and e l l ip t ica l . W i th the necessary exception of the sixth type, only straight edges are shown inthe d iagrams, bu t there a re obvious var ia t ions wi th curvededges. Th e sam e princ iple, of course, applies to tai lpla nep l an .

Elliptical

B i p l a n e sA DM ITT ED LY v e ry mu ch i n t h e mi n o r i ty n o w ad ay s ,

**- the biplane is, how ever, an yth ing bu t obsolete andcan be d iv ided in to two broad c lasses : those wi th equalwing-span and those having a top wing of greater spantha n the lower one. In both classes the wings m ay bese t one immedia te ly be low the o ther, o r they may be s taggered, i .e . , the lower wing set farther back than the topone and with sloping inter-plane struts.

Staggered

Ta i l sD E A D E R S o f Flight should , by now, be fairly fam il iar

- -* wi th the wid e va rie ty of design in ta il assem blies .But ignoring the almost endless choice in surface contours,their structural features fal l into a series of clearly definedgrou ps. These m ay be classified according to the n um be rof fins and rudders (considered as a single unit) and theirposi t ion in re la t ion to the ta i lp lane . The y must a l sovb e

classified according to the posi t ion of the tai lplane in rtftrtion to the cross-section of