Variation-selection in the innovation of the retractable airplane landing gear: the Northrop

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Variation-selection in the innovation of the
retractable airplane landing gear the Northrop
anomaly

• Walter G. Vincenti

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Quick Summary

• In the early 1930s, airplane landing gear went
  through the process of technical change.
• However, Northrop introduced a modified landing
  gear, which looks anomalous in the context of its
  time.
• It proves a typical of the variation-selection
  learning process normal in engineering.

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Revolution in Airplane Landing Gear (1930s)

• Retractable landing gear entered prominently into
  airplane design in the first half of the 1930s.

Fixed Gear Retractable Gear
simple design of bars, wheels, and brakes that are not retractable into the wings or fuselage The landing gear is attached to motors which lower it before landing
reduces the risk of problems at landing, but it does create extra drag during flight causes no extra drag. increases the length of flight significantly
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Northrop Alpha - Initial version

• Inaugurated the series in 1930.
• Featured stressed-skin all-metal construction.
• Channel-shaped aluminum wing
• FIXED landing gear

A retractile gear is being designed to be
incorporated later. (1929) -Jack Northrop
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New Northrop Alpha
Pants type gear
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Northrop

• Following the XFT-1, Northrop began apparently to
  see the trade-offs differently.
• As speeds continued to climb, the need to reduce
  drag became dominant.
• Gradually went over to the retractable gear.

Northrop Grumman B-2 Spirit
?? retractable landing gear? ???? ???? ??? ???
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Unforesigtedness

• Northrops trouser gear served as a variant.
• What is the take-away from the blind persons
  story?

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What is Variation-Selection Model?
Design 2
Design 3
Design 1
Dominant Design
Design 4
Design 7
Design 5
Design 6
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Theory vs Practice

• Theory has a limited role in guiding practice.
• Practice serves indispensably to appraise (or to
  reshape) theory.

Science? ??? ??
Heuristics?
Dosi (1982) defined technological paradigm as
model and a pattern of solution of selected
technological problems, based on selected
principles derived from natural sciences and on
selected material technologies.
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Scientific realism vs Relativism
Realism or Relativism for Technical change
theory?
Uninterpreted Reality
Scientists worldview
Research Paradigm
Mental Interpretation of Reality
Public Construction Of Reality
Scientific Realisms view of Reality
Relativistic view of Reality
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Critique / Further Research Suggestions
The major difference between scientific realism
and relativistic view is in the nature of
scientific reality. I personally think the
authors view is more close to relativistic
view - the concept that points of view have no
absolute truth or reality, which I totally agree
with him. Because the way how technology is
adopted and change is more relative, subjective
according to differences in perception and
consideration.
Because this article was more like a case study,
it is difficult to criticize any shortcomings. I
think it would be interesting if we look at other
cases where we can see the variation-selection
learning process. Also it may be interesting to
look at how the environment changed after the
technical change in the landing gear occurred,
like the study done by Tushman and Anderson
(1986).
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Thank you