Archangel_article.pdf

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February, 1950

AEROMODELLER

GAB RI ELS'

23 years old . . . . press toolmaker

by trade . . . . startid modelling 11

years ago,but due to study and ser-

vice in R.A.F. had little time until

'48 . . . . Press Sec. to Oldham

and District M.A.C. . . . . usos oM

lathe for engine making .. . . firet

interest sailplanes, secoud power

., . . other hobby photography,

used mainly with models.

to stand up to

nESIGNED

hard knocks and the windy

weather of l.he North-Westerir

Area, the original is now 18

months old and still flying.

a result of one of itd two flv-

arvays, the model spent l.l winter

'Ihe

weeks on open moorland.

only damag-e suffered was a few

tears in the tissue and a waroed

tailplane. Archangel can be built

on a 30 in. drawins board.

The flight timeJ average over

4 minutes, and consistency is the

hallmark of the model's p6rform-

11ce-. It has been well placed regularly in Contests, always in

the first half dozen.

Construction.

Sta.rt by cutting out the formers and write your name and

address on F3, so that it can be seen inside the cabin.

Now mark out the two sides by piercing the outline on the

plan on to l/32nci in. sheet balsa using a pin. Cement the four

side longerons in place on the sides and add vertical spacers.

Mark the former positions on the sides and cement the

formers in place, setting them squarely. The cement having

dried, join the rear ends and clamp. Check for alignment.

Cut cross-braces in pairs and fit between side lonserons.

Now add paper tubes and hooks, and then sand fuselafe.

After shleei-covering, fix nose-biock ancl cover fusela{e with

rag tissue. Two coats of clear dope finely sanded, the addition

of the windscreen and colour dope complete the fuselase,

The door of the dethermalizer'chrlte comiartment shouldie

separated with a sharp blade and hinged with nylon.

Make up the mainspars, building in the outboard dihedral.

Cut out {our ply root ribs and face with l,z8th in. sheet balsa.

Clamp these togcther, yibs No. 2 being l/lDth in. higher than

ribs No. I and drill the dorvel holes.

Cement paper tubes at right angles to ribs No. l. Thread

ribs No. 2 loosely onto the tubes and insert mainspars. Support

these at the correct dihedral anqle on a level surface, insert

I in. dowcls in the tubes and adj-ust distance between ribs to

make dowels parallel with level surface. The whole set of ribs

is now cemented in place. Now

add trailing edge and wing-tips

and, alter sanding to cnsure a

a flat seating ior the leading

edge, cement this member in

place. Add appropriate sheet-

ing, sand and cover. Balance

wings bcfore and after covering.

Construction of tailplaneand fi n

is straightforward, the only point

to be watched being the fixing of

the auto-rudder.

If the locking-

pin should fail to pull out, th1

results will be disastrous, so en-

sure that the wire rinss are a

loose fit and lined up correctly.

I Toilplane fixing, outo-rudder and

I Pin attochment are shown, left,

'chute stowed in

I dethermolizer

bortment with the door oben.

locking-

ond the

its com-

rieht.

For the same reason, the rudder spring must not be too strong.

The prototype was covered with Jap tissue, which was found

to be the strongest available. Grain should, of course run

from root to tip on wings and tailplane.

Two coats of thinned hear,y waterproof dope were applied

first, followed by two coats mixed wit}a 5o/o of castor oil.

Experiment

may be necessary as to the best quantity of

castor oil to add with a particular brand of dope, The proper

percentage will prevent over-shrinking

and consequently,

warps, and make a completely waterproof job.

The dethermalizer has been used in all weathers, and there

have been only two flyaways as a result. In both cases the cause

was faulty fuses; the use of parachute nylon, with its crease-

resisting qualities, makes the'chute 100 per cent. foolproof.

Thc 'chute is 14 ins, square and has four shroud lines.

attached one at each cornei, these being 14 ins. long. In the

centre of the 'chute, a 3 in. diam. hole is cut. A11edges should

be hemmed or doped to avoid fraying.

The 'chute is attached

to a hook on the fuselage under the tailplane and an eiastic

band draws it out of its comDartment when the door is released.

Trimming.

First, check all surfaces for warps and if any are present,

remove.

It is bad policy to endeavour to cancel out warps

with the rudder : in level flight the results mav be fair, but on

the line, towing difficulty rnay be experienced

When the

C.G. has been adjusted to the position shown, limit all

trimming to the tailplane.

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