G R IN D IN G SPINDLES D R ILL J IG BUSHIN GS C O N TIN EN TA L CU TTIN G TO O LS
TO O L GRIN D ERS FUEL IN JEC TIO N EQ U IPM EN T
R . R . PIN S A N D BUSHINGS PU R E -P A K P A P E R M ILK BOTTLE
M ACH IN ES PR ECISIO N A IR C R A F T A N D
M ISC ELLA N EO U S PRO D U CTIO N P A R TS PRECISIO N T H R E A D G R IN D IN G
M A CH IN ES
PR ECISIO N L A P P IN G M ACH IN ES PR ECISIO N B R O A C H SH A R P E N IN G
M ACH IN ES OTH ER S P E C IA L PU RPO SE
M A CH IN ES B R O A C H E S A N D B R O A C H
FIXTU RES H Y D R A U L IC PO W ER UNITS S P E C IA L M ULTIPLE W A Y -TYPE
PR ECISIO N B O R IN G M A CH IN ES S P E C IA L M ULTIPLE PR ECISIO N
D R ILLIN G M ACH IN ES
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EX-CELL-O CORPORATION • DETROIT 6
Above: Ex-Cell-O Special Style 58 Tw o-W ay Machine for finish boring center and both ends of differential transmission case (of chrome nickel iron— shown in two views). This Ex-Cetl-O machine combined several operations formerly
necessary, and greatly increased production.
Below: Ex-Cell-O method o f bolted construction. Linked in this manner are the wing sections of the machine that carry the spindles, and the center pad
section that carries the work fixture.
This Ex-Cell-O feature o f construc
tion provides not only added strength and rigidity but greater flexibility.
When desired to machine a part of different dimensions the center sec
tion can easily be removed and a section o f different size substituted.
m x m m a p l u s p a l l e t i z c ü .
speed up
A T T E R I E S
T H E E L E C T R IC S T O R A G E B A T T E R Y C O M P A N Y , P h ila d e lp h ia 3 2 , Exide Batteries of Canada, Limited, Toronto
242 / T E E L
W I N G T I P S
Indicative of tk'e variety and grotesque shape of typical aluminum forgings used in combat airframes is this view of one of the inspection benches at the Dodge aluminum forge plant in Detroit. This plant has produced literally hundreds of types of forgings for over 20 different fighter planes and bombers and was built specifically for this type of production. Steam hammers range up to 20,000-
pound siz'e. Most forgings are of 14ST alloy
the Bell Airacobra except for the installa
tion of twin jet engines instead of the conventional Allison engine and propel
ler. The engines were based on designs of a British engineer, Capt. Frank Whittle, and were built by General Elec
tric. Essentially they comprise a coax
ially mounted blower-compressor and gas turbine, the former ahead of the latter and serving to compress the inrushing blast of air from a frontal air scoop, then delivering it to the turbine after passing fuel jets which inject atomized fuel to make an explosive mixture. “Hot” wires or spark plugs ignite the mixture arid the resulting explosive force drives the turbine and then is ducted through a rear venturi, the reactive force serving to propel the plane.
While the Airacomet performed suc
cessfully, it apparently became obsolete shortly after its appearance, for produc
tion contracts were sharply scaled back.
Principal objections to this type of en
gine are the high fuel consumption at speeds below 500 miles an hour and the comparatively short life of the engine.
Temperatures resulting from a continu
ously exploding gasoline mixture impose severe demands on turbine blades par
ticularly and on other parts of the en
gine as well, so that continuous opera
tion is not possible beyond a short pe
riod. In fact the engine would not have been successful at all were it not for perfection of a suitable alloy for the tur
bine buckets. Based on experience with turbosuperchargers, a material known as Vitallium—similar to Stellite—was used and cast into the bucket form. The al
loy is unmachinable and hence was pre
cision cast by the lost wax process. Later research has indicated a change to Hastelloy B, forged to shape, but little has appeared on this development.
This type of jet engine obviously would lend itself to a combination type of operation—that is, both propeller and jet. At lower speeds the compressor-tur- bine shaft might be coupled to a propel
ler and at higher speeds switched over to pure jet force. In fact, it appears strange the first application of the gas turbine, which is essentially what the engine is, was not in a propeller-type in
stallation; certainly some experiments in
this direction can be looked for.
The German V-l robot bomb, which made its appearance in 1944, represented an ingenious application of the jet prin
ciple to an impulse-reaction type of “en
gine” of amazingly simple and low-cost design. Briefly, all it comprises is a long, tapered steel tube externally mount
ed, with a flap-valve grille at the front in which are incorporated six fuel jets.
Inrushing air forces the flaps open, fuel is sprayed into the air, ignited by a hot wire, exploded through a venturi and the force of the explosion both drives the bomb forward and closes the flap valves, after which the entire cycle is repeated several hundred times a minute. No particular metallurgical complications are involved in this type of power unit, but at that it had only limited life, prob
ably burning out in well under an hour if allowed to continue in operation. For experimental purposes, this type of en
gine was duplicated by Ford Motor Co.
and attached to winged bombs manu
factured by Willys-Overland.
At year-end, first details of the V-2 and V-3 jet-propelled bombs were re
leased by the British, revealing them to be much more complicated and powered by liquid oxygen and alcohol combusted through a venturi, with a maze of con
trols and accessories including turbine- pump unit, nitrogen, hydrogen peroxide and permanganate supply, electric mo
tors, radio equipment, chain-driven con
trol vanes and a comparatively small one- ton explosive war head. They were unique engineering achievements.
Practical application of jet propulsion as yet is some distance away, despite the fact the AAF has said its present fighter plane models, such as the P-47 Thunder
bolt, the P-51 Mustang, the P-38 Light
ning and the P-61 Black Widow, repre
sent the last fighter planes to be built with conventional gasoline engines, sug
gesting future models will be jet
pro-E M P L O Y M pro-E N T IN A IR F R A M pro-E , pro-E N G IN pro-E A N D P R O P pro-E L L pro-E R PL A N T S A N D P E R C E N T F E M A L E E M P L O Y M E N T
P e r c en t P e r c en t P e r c en t P e r c e n t
Y ear A irfram e F e m a le E n g in e F e m a le P ro p e lle r F e m a le T o ta l F e m a le
Jan ., 1941 1 4 6 .1 9 7 NA 4 1 .3 2 9 NA 6 .6 0 9 NA 1 9 4 .1 3 5 NA
Jan ., 1942 3 4 1 6 0 3 5 .5 1 0 4 ,1 5 6 3 .8 1 4 .5 9 7 3.8 4 6 0 .3 5 6 5 .0
Tan., 1943 7 7 0 ,4 7 1 3 5 .6 2 1 9 ,0 8 4 18 .8 3 8 .S 5 9 16.4 1 ,0 2 7 ,9 1 4 3 1 .3
Aug., 1944 7 6 9 ,2 8 2 4 0 .0 3 1 7 ,3 4 6 3 0 .4 5 3 ,2 9 1 2 8 .3 1 ,1 3 9 ,9 1 9 3 6 .8
Source: U . S. D e p t, o f L a b o r, B u r. o f L a b o r S tatistics, C o n stru ctio n a n d P u b lic E m p lo y m en t D ivision.
January 1, 1945 243
W I N G T I P S
pelled. Germany has at least two-jet- propelled fighter planes now in action.
As far as is known, the United Nations have none. Commercial use of this type of power is still remote.
Application of water injection to en
gines of conventional types of fighter planes during 1944 showed interesting possibilities, especially as a means of stepping up “burst” horsepower in com
bat. Systems were being installed on both radial and liquid-cooled engines, and gave pilots an extra power edge in maneuvering against the enemy. Water is injected only in short spurts, con
trolled by tire pilot, although on tests it
T O T A L F L O O R SP A C E O F A IR C R A F T , E N G IN E A N D P R O P E L L E R A SSEM BLY PL A N T S
(Sq. ft., 0 0 0 o m itte d )
Y ear A ircraft E n g in es P ro p e lle r T o ta l J a n ., 1 9 4 0 9 0 0 6 3 ,0 1 8 4 9 2 1 3 ,1 1 5 J a n ., 1941 1 7 .9 4 3 6 .4 6 3 1 ,0 5 0 2 5 ,4 5 6 S ep t., 1941 3 1 .7 8 6 10 651 1,7 3 4 4 4 ,1 7 1 J a n ., 1 9 4 3 7 7 .5 3 6 3 1 ,8 2 9 5 ,2 4 0 1 1 4 ,6 0 5 D ec., 19 4 3 1 1 0 .4 2 3 5 4 ,1 8 9 6 ,8 3 8 1 7 1 ,4 5 0 Ju n e, 19 4 4 1 0 8 ,3 6 3 5 5 ,2 2 0 3 ,6 1 6 1 6 7 ,1 9 9 S ource: 1 9 4 0 -1 9 4 1 : Q u estio n n aires of th e A e ro n a u tic al C h a m b e r o f C o m m erce. 1943:
A ircraft R esources C o n tro l O ffice, R ep o rt 15 (M onthly Sum m ary). 19 4 4 : Q u o te d from " L a b o r S tatistics fo r A irc ra ft In d u s try ” p re p a re d b y M an p o w er B ran ch , A ir T e c h n ic al Service C o m m a n d , W rig h t F ie ld , D ay to n .
has been applied successfully for as long as 15 minutes.
Air-borne radar equipment is a highly secret development but one being pushed aggressively. The only warplane yet an
nounced as radar - equipped is the Northrop P-61 twin-engine night fighter, although there are undoubtedly others.
The P-61 Black Widow is said to mount a unique type of binocular radar. The purpose of radar briefly is to detect ob
jects some distance ahead of the attacker by means of projecting short-wave elec
trical impulses, some of which rebound from the undisclosed object, and are re
captured and indicated by the radar equipment.
Numerous other minor embellishments have been perfected to sharpen and ex
tend the performance of warplanes. Aux
iliary jettison-type gasoline tanks, of compressed paper, aluminum or steel, constitute one innovation to extend the range of aircraft. Remote control sys
tems for electrically sighting and operat
ing gun turrets on large bombers are an
other. The latter arrangement is a fea
ture of the B-29 Superfortress, and per
mits gunners to “gang up” all the gun turrets and operate them from inside the pressurized cabin, or they may be op
erated manually if preferred. Mounting of cannon up to 75-millimeter size on light bombers is still another successful modification.
Important strides have been made in supercharging, most of the large engines now produced being equipped with two- speed two-stage supercharger systems.
One stage is driven by exhaust gases through a turbine; the other mechanical
ly geared. A P-51 fighter plane so equipped is said to have been operated at a speed of around 540 m.p.h. and at low altitude, although this practice is not recommended and results in inordi
nate engine wear. The two stages of supercharging are aimed primarily at im
proving high-altitude performance.
There are indications the reciprocating type of internal combustion engine has reached the peak of size and power for aircraft use. Largest engines now in pro
duction are the Allison 24-cylinder 3420- cubic inch displacement model and the Wright 18-cylinder radial 3350-cubic inch displacement model, each providing close to 3000 takeoff horsepower. Going into production is a 28-cylinder four- row radial with around 4300 cubic inch displacement, but it well may run into trouble with cooling the rear banks of cylinders, in view of the serious difficul
ties experienced on this score by the Wright 3350 engine over the past two years.
Aluminum and steel continue to be
D O L L A R V A L U E O F A IR F R A M E , E N G IN E A N D P R O P E L L E R P R O D U C T IO N
(0 0 0 o m itte d )
Year A irfram es E n g in es P ro p ellers
1941 ... $ 8 2 0 ,0 0 0 $ 4 9 6 ,0 0 0 $ 9 9 ,0 0 0 1 9 4 2 ... 2 ,7 6 9 ,0 0 0 1 ,6 1 8 ,0 0 0 3 0 7 ,0 0 0 19 4 3 ... 6 ,8 5 6 ,0 0 0 2 ,8 1 8 ,0 0 0 6 2 6 ,0 0 0 1 94 4 , F ir s t
3 Q u a rte rs 7 ,8 0 8 ,0 0 0 3 ,0 4 9 ,0 0 0 6 0 5 ,0 0 0 Source: W a r P ro d u ctio n B oard, B u re au of P ro g ram S tatistics, M ilitary D iv isio n , A ir
c ra ft B ranch.
basic aircraft materials, although the trend toward increasing use of magnesi
um in both cast and wrought forms re
mains upward. The aircraft industry consumes approximately two thirds of
( Please turn to Page 404)
Battery of multiple drills in th e plant of Boeing Aircraft Co., Seattle. Common work table permits ready transfer of parts from one machine to another
244 / T E E L