DEVELOPMENT TIME SCALES FOR BRITISH AND AMERICAN MILITARY AIRCRAFT
| Published date | 01 June 1972 |
| DOI | http://doi.org/10.1111/j.1467-9485.1972.tb00515.x |
| Author | Keith Hartley |
| Date | 01 June 1972 |
DEVELOPMENT TIME SCALES FOR BRITISH
AND AMERICAN MILITARY AIRCRAFT
Type of aircraft
U
K.
Military
8
years 4 months
Civil 4 years 4 months
-~-
KEITH HARTLEY
-
U.S.A.
6
years
3
months
3
years
7
months
-
-
INTRODUCTION*
In the post-war period, the
U.K.
aircraft industry and government aviation
policy have been subjected to a variety of criticism relating
to
such issues
as cancellations, cost-estimating, contract pricing and export performance.
Criticism has also been made of the lead times from initial design to first
deliveries to customers for military and civil aircraft. Frequently, it has been
suggested that compared with the
U.S.A.,
British aircraft have generally taken
longer to develop. This article will consider one aspect of the British aircraft
industry's performance in the post-war period, namely the calendar time
taken to design, develop and produce aircraft compared with the U.S. industry.
Initially, the evidence will be briefly reviewed, after which
a
simple model
for explaining time scales will be presented and subsequently tested.
Source: Productivity
of
the National Aircraft Effort,
HMSO,
1969. ch. 11. Averages are based on samples of 12 British
and 21
U.S.
military aircraft and for civil aircraft,
7
British
and
8
U.S. projects (all post-1945).
For
military projects,
development time was defined as the period between the
issue of an Operational Requirement to service release; with
civil aircraft, the corresponding period was from the start
of detailed design work to the issue of a certificate of
airworthiness.
Table
I
shows that military aircraft generally take longer to develop than
civil projects. This difference partly reflects the process of deci sion-taking in
*
The author benefited from comments received from Paul Burrows, Ron Cooper,
Charles Rowley, Robin Shannon and Alan Williams.
115
116
KEITH
HARTLEY
the defence departments. It also arises because military projects generally
involve substantial advances
in
technology, with some of these advances
being applied at a later date to civil aircraft. At the same time, Table
I
appears to provide conclusive evidence of the relatively shorter development
times in the U.S.A. Unfortunately, though, the evidence fails to distinguish
the various characteristics of the aircraft projects undertaken in each country.
For example, for the sample of civil aircraft included in Table
I,
the
U.S.
projects have on average tended to
be
heavier and capable of greater speeds
suggesting that the
U.K.’s
‘
disadvantage
’
is even greater than is indicated by
a simple averaging process. However, a review of the evidence only identifies
longer time scales for
U.K.
projects
:
these facts require an explanation.
A MODEL
OF
TIME
SCALES
Consider the problem of undertaking a new aircraft project which
involves an advance in technical knowledge. Expenditures are required to
obtain technical knowledge and
so
reduce the uncertainties associated with
a project. Since improvements in knowledge are not costless, some minimum
resource input will be required for project completion and there will be an
associated time period for the development work. Where decision-makers
regard the resulting time period as
‘
too long
’,
then the technical problems
might be solved in a shorter time span by allocating more resources to the
project. However, as development teams exceed their optimum size, dimi-
nishing returns will be evident and additional resource inputs will lead to
successively smaller time savings.l Thus, the analysis suggests that to achieve
a given product, time and resources can be regarded as inputs with possibili-
ties of substitution at the margin. This can be shown by a conventional
iso-quant diagram which specifies all the possible combinations of time and
resources required to develop a given aircraft.’
An
example is shown in
Figure
1.
Figure
1
provides a basic analytical framework which can be used to
suggest explanations for the differences in time scales between comparable
British and American aircraft.
An
obvious starting point is expenditure.
Ceteris
paribus,
longer development times in the U.K. might be explained by
a smaller resource input (e.g.
El
in Figure
1)
for a given project. This imme-
diately raises questions about the determinants
of
expenditure on aircraft
projects
in
each country and especially the relative valuations which buyers
and sellers place on time and expenditure (and quality). For example,
U.S.
decision-makers might value time-savings more highly than their British
counterparts. Similarly, U.S. and British decision-makers might be subject
to different resource constraints on a given project.
*
The available stock
of
knowledge in relation to the outstanding technical problems
can be regarded as the
‘
fixed
’
factor.
See
e.g.,
M.
Peck
and
F.
Scherer (1962, Ch. 9). The iso-quant in Figure
1
relates
to
a
given aircraft or quality, where quality
is
measured
by
such variables as speed, range
or altitude.
Also,
Harvey
(1970).
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