February 13, 1930. The Model Engineer and Practical Electrician.
1 3/16th ins. Above and below this width the
static thrust fell off. This was determined by
gradually reducing a wide blade to a narrow
blade.
Weight of Propeller.
The weight of a propeller should also be
taken into consideration, which few except the
ultra light-weight model. builders do.
However,
the inexperienced
model
flyer
should not start off with a light-weight propeller
because he will probably very soon break it, for
reasons which need not be gone into here. But
an impression prevails that a heavy propeller has
a flywheel effect which helps to keep up its
speed. This is a fallacy. Any model engineer
knows that the heavier the flywheel the more
power required to drive it at a constant speed.
The same applies to propellers, and consequently
a light propeller requires less power to drive
it than does a heavy one. What really happens
is when the power is shut off a heavy propeller
will continue to run for a little longer time than
a light one, which is no advantage.
The weight of the 12-in. propeller to be
described later was exactly i oz., the minimum
weight allowed by the rules of the static thrust
competition.
It was made of walnut wood,
laminated.
Shapes of Blades.
Many designs of propellers have been tested
on the “ Thrustometer," as it has been aptly
named by the Harrow Scientific Society, but
none has given such good results as the old
Chauviere pattern.
This type has been superseded by more symmetrical designs in full-sized
work owing to the unequal stresses imposed
upon it at high speeds and constant danger of
distortion and fracture.
But this matters little
in model work, as the blades are strong enough
to resist all strains imposed on them in actual
flying. A symmetrical design is frequently met
with on commercial model aeroplanes, the chief
reason being its immunity from breakage with
rough landings in the hands of those who have
never handled a model aeroplane before.
165
The meetings are free to all members of the S.M.A.E., affiliated clubs, and anyone interested in model aviation wil be heartily welcomed. Visits.—Following the very successful visits to the factories of the Desoutter Aircraft Co. and Messrs. Hawker recently, a further outing has been arranged for March 1, when Dr. А.Р. Thurston will conduct a party over the aeronautical section of the Science Museum, South Kensington (South Kensington Station, District Railway). There will be no charge, but members of the S.M.A.E. or affiliated clubs who wish to join this party should notify the hon. secretary by post-card as soon as possible. The place of meeting will be the entrance to the Science Museum, and the time 3 p.m. Hon.
Secretary,
Westminster
S.
Avenue,
G.
MULLINS,
Thornton
Heath,
72,
Surrey.
The Model Aircraft Club. (T.M.A.C.) The flying season of The Model Aircraft Club will begin on Saturday, March 1, at 2.30 p.m., on Wimbledon Common (near the Windmill), when a grand display of flying models will be held, including petrol, compressed air, rubber driven, heavy and light models. All members should make a special effort to be present. Will all members of T.M.A.C., provincial or otherwise,
make
a note in their diaries that
the first Saturday in the month is booked for competitions and displays under T.M.A.C. rules during 1930. Rules and full particulars of meetings will be published at an early date. All communications should be addressed to the Hon. Secretary, A. E. Jones, 48, Narcissus Road, West Hampstead, N.W.6 (Phone,
Hampstead The
8363).
Model
Aircraft
Construction
Society.
the Y.M.C.A., Tottenham Court Road, W.C., were arranged: Tuesdays, February 18, March 4
Our first meeting took place on January g. The following resolutions were adopted :— (a) The aims and objects in view comprise a scientific study of the problems of flight in the least expensive way. (b) Officers elected: Gliding Instructor, Mr. F. Granger; Hon. Secretary, Mr. F. A. Lowe; Hon. Treasurer, Mr. H. Worrell; Committee, Captain Narbeth and Mr. P. Reynolds. (c) Subscription would be nominal for working expenses only, any expenses incurred with full-size gliding will be footed separately, also prizes for model competitions. (d) A generous offer of a complete biplane glider, ‘‘ The Linnet," was readily accepted under the conditions presented by the donors, Messrs. Granger Bros.; the glider is a singleseater fuselage biplane, with wings mounted high. (e) As it is desired only to increase membership with really enthusiastic presonnel, all newcomers must be voted into the Society ; further, the Society will not seek recourse to any form of advertising, the only publications in future will be a monthly report of our activities to THE Море. ENGINEER and the S. M.A.E. journal. (f) A private gliding and model flying ground has been secured ; our first meeting in full force will take place on Easter Saturday. (g) The question of affiliating to othet Societies is being considered.
and 18. All meetings commence at 7.30 p.m., and full particulars will be published shortly.
Hon. Secretary, Francis A. Bramcote Road, Beeston, Notts.
(To be concluded.)
Society of Model Aeronautical Engineers. The Annual General Meeting was held at the Y.M.C.A., Tottenham Court Road, London, on Tuesday, January 28, when the following officers were elected for the year: President,
Air
Vice-Marshal
Sir
W.
Sefton
Brancker,
K.C.B., A.F.C.; Vice-Presidents, Dr. A. Р. Thurston, D.Sc., F.R.Ae.S., M. I.A.E., M.I.M.E., and R. M. Balston, Esq. ; Chairman,
А. F. Houlberg, Esq. ; Vice-Chairmen, W. Е. Evans, Esq., and R. Langley, Esq.; Hon. Secretary, S. б. Mullins, 72, Westminster Avenue, Thornton Heath; Hon. Treasurer, W. E. Evans, 20, Thurlby Road, Wembley; Competition Secretary, S. H. Crouch, 23, Mayfair Avenue, Ilford; Technical Secretary, R. N. Bullock, 76, Boyne Road, Lewisham; Councillors, Messrs. S. R. Badley, J. E. Pelly Fry, J. van Hattum, S. C. Hersom, B. K. Johnson, H. E. Onion, D. A. Pavely, W. J. Plater.
Meetings to be held on the following dates at
Lowe,
24,
