Classification with Peek-a-boo for Indexing Documents on Aerodynamics: An Experiment in Retrieval
R.C.WRIGHT and C.W.J.WILSON
ABSTRACT. A new classification and peek-a-boo cards were used for the analytical indexing of documents on aerodynamics and 100 test questions were put to the system. Degree of success in retrieval is assessed, input and search times are measured, and causes of failure are examined. The combination appears to offer a promising retrieval system for complex but well-defined subjects.
Towards the end of 1956, it was proposed to prepare and (as far as possible within security limits) to distribute to industry a subject index to the reports and technical notes issued by the Aerodynamics Department of the Royal Aircraft Establishment. This index, which might later be extended to include other series of reports on aerodynamic subjects, would be based on a suitable classification system permitting conjunctive specification, and would use a clerical device of the peek-a-boo type (1). The system would employ a minimum of expensive equipment and, if successful, might be applicable to other fields requiring detailed analytical indexing of a comparatively small collection. First, however, it would be necessary to select a suitable classification of aerodynamics, do some trial indexing, and carry out tests on the system. The purpose of this paper is to describe the selected classification, the posting and searching operations, and the tests carried out.
Purpose of the experiment
Main reasons for undertaking the project were:
-
A reliable analytical index to the 6000 reports in the series was necessary to the Establishment and would no doubt be welcomed by the aircraft industry.
-
Mr. J.Seymour, a former Librarian of the Aerodynamics Department, had recently developed a classification for aerodynamics which appeared to
R.C.WRIGHT and C.W.J.WILSON Royal Aircraft Establishment, Farnborough, England.
-
have many advantages for use in a retrieval system. Experience in its practical application was desired.
-
Tests had already been carried out with a Uniterm system for cataloguing aircraft structural data (2), and on the N.L.L. card catalogue of aerodynamic measurements (3, 4). Similar evaluation of a peek-a-boo device based on a suitable subject classification was considered desirable.
-
It was hoped to ascertain whether an analytical indexing and retrieval project in the complex subject of aerodynamics could be designed and operated by professional librarians without specialist subject knowledge, to the satisfaction of the aerodynamicists requiring the information.
PHYSICAL FORM OF THE INDEX
In its final form, the index would be made up of (1) a register, i.e., a list of all documents indexed by the system, in register serial number order; (2) a manual, consisting of (a) an introduction to the system, (b) a list of subject headings in classified order, (c) an alphabetical index to the subject headings; (3) index sheets—one for each subject heading and for each designated aircraft and aerofoil; register serial numbers of documents to be indicated by the positions of punched holes.
For testing purposes, however, it was decided to use only the classification schedule itself and standard 80-column Hollerith cards. Special cards or plates having a higher capacity might later be desirable, but their design, and that of suitable punching and viewing devices, could be left until the retrieval capabilities of the system had been investigated.
Choice of classification
After consideration of the known enumerative classifications of aerodynamics, including U.D.C., N.A.C.A., and the N.L.L. (all of which are used to some extent in the Establishment), it was decided to adopt the classification system devised by Mr. Seymour with this project in mind. After comments had been sought from subject experts, the classification was adopted with slight modifications; it appears as Table 2, together with the number of times each code was used in indexing the first 700 documents. It was expected that further modifications would follow an initial trial period of indexing.
Indexing
THE INDEXERS
The six indexers were professional librarians employed in the Main and Departmental libraries of the Establishment. One of them (A) was librarian
of the Aerodynamics Department: the remainder (B-F) had experience in aeronautical libraries but no special knowledge of aerodynamics. About half of the indexing and searching was to be done by A, so that the effect of familiarity with the subject and with the schedules might be assessed.
Before starting to index, the indexers met to discuss the schedules and to resolve as far as possible differences of opinion as to the meanings or the use of particular headings. Each person then indexed a number of test pieces, and variations were discussed. It was intended to introduce further test pieces at later stages in order to see whether improved correlation came with experience of the system.
PROCEDURE
For test indexing the selection of documents was not limited to R.A.E. documents, some Institute of Aeronautical Sciences preprints and National Advisory Committee for Aeronautics Research Memoranda being included in order to achieve wider subject coverage, particularly of recent material.
The intention was to code all those features of a document which might conceivably be used later as part of an information request. A detailed study of each document was therefore necessary, particular attention being given to the summary, conclusions and illustrations. Postings were made on a 5 by 3-inch card ruled in ten columns as follows:
Thus, to indicate that a document dealt with a fighter aircraft, the code 157 taken from the schedules would be entered as 15 in column 7. All relevant codes were entered, so that the issue date 1953 would be coded as 103, 104, 105, 106, and Mach number 1.3 would be 121, 122, 123, 124. Whenever a sub-heading was used, the main heading above it was also coded. For peek-a-
boo use, these codes were subsequently transferred to lists in code number order and punched on Hollerith cards.
The only materials and equipment used were common stationery items and a Hollerith hand punch. The processes involved were:
-
Examination of the document and noting appropriate codes on the 5″×3″ card illustrated above.
-
Listing the serial numbers appropriate to each code number.
-
Hand punching the Hollerith cards, which already have typed on them the code numbers, by which they are arranged.
Times taken for these operations are discussed later. The most time consuming, and that needing the highest-paid staff, was (a). Most documents were assigned about 30 codes. At first, indexers were taking as long as 30 minutes for each document: practice, familiarity with the schedules and increasing knowledge of the subject soon reduced this to 15–20 minutes per document. It is doubtful whether an average of about 15 minutes can be much reduced, in view of the careful study of each document which is necessary to any system using highly analytical indexing. The average salary of the indexers employed worked out at 10/– ($1.40) an hour.
Description of tests
The test programme is in two parts:
(a) When about 750 documents have been indexed. To ascertain the effectiveness of the classification, to make any necessary modifications to the schedule, and to remove causes of discrepancy between indexers. Also to assess the cost of indexing and posting and the speed of searching operations.
(b) When about 3000 documents have been indexed. To ascertain the number and relevance of documents retrieved in response to a given question. Also, on the basis of search times, to ascertain the scope and form of the final index (a) for internal use and (b) for possible issue to other aeronautical libraries. Only part (a) of the programme is discussed in this paper.
When 700 reports had been indexed (500 R.A.E. documents and 200 of U.S.A. origin), ten R.A.E. aerodynamicists were asked to collaborate by selecting 10 documents each from the collection and framing one question on each document. The questioners had not seen the classification schedules, and were asked to frame in their own words the sort of question that might occur in their daily work. The questions appear in Table 1. Searching was divided about equally between indexers A and B. Success was defined as the retrieval of the document on which the question had been based. Obviously this had
to be limited in some way, since a search which retrieved the subject document together with about 50% of the collection could hardly be regarded as an unqualified success. Such a case could be due to faults in retrieval; it could also be due to the question having been so general that it was bound to produce a large number of answers.
After discussion, an arbitrary limit of 5% of the collection (35 documents) was set as the maximum for a search to be regarded as successful. Searches producing more than this number have been classed as “partially successful” provided that the subject document is included.
When a search was unsuccessful, a second search was usually made, either by the same searcher or by the other. Sometimes this consisted simply of widening the original search by discarding one or more of the factors forming the specification. In other cases completely new headings were selected to form a new search plan.
Usually not more than two searches were made, but there were a few cases in which a third search was considered advisable.
Analysis and discussion of results
PERCENTAGE SUCCESS
Of the 100 questions put, 54 were answered at the first search, a further 20 by a second search, and a further 4 by a third. In 7 cases the search was “partly” successful (subject document retrieved, but with more than 5% of the collection), and in 15 cases the search failed completely. An overall success percentage of 78 (plus a further 7% of cases in which the field was appreciably narrowed) is not unsatisfactory having regard to the circumstances in which the test was made. Many of the questions would, in normal information work, have been referred back for amplification.
CAUSES OF FAILURE
(a) Causes of complete failure
|
Question numbers |
||||||||||||||
|
1 |
7 |
12 |
32 |
34 |
36 |
39 |
40 |
51 |
53 |
57 |
66 |
81 |
88 |
93 |
Misleading question |
|
|
|
|
X |
|
|
|
X |
|
|||||
Question misinterpreted |
X |
X |
|
||||||||||||
Indexing omission |
X |
|
X |
|
X |
X |
X |
X |
|
X |
X |
X |
X |
X |
X |
Schedule inadequacy |
X |
|
|
X |
|
X |
|
(b) Causes of partial success
|
Question numbers |
||||||
|
17 |
23 |
24 |
26 |
28 |
61 |
70 |
Question insufficiently specific |
|
|
X |
|
X |
|
|
Indexing omission |
X |
|
|
X |
X |
X |
X |
Schedule inadequacy |
|
X |
|
(c) Causes of earlier failure when third search successful
|
Question numbers |
|||
|
37 |
41 |
48 |
67 |
Question misinterpreted |
|
|
|
X |
Indexing omission |
X |
X |
X |
|
(d) Causes of earlier failure when second search successful
|
Question numbers |
|||||||||
|
4 |
5 |
11 |
22 |
25 |
31 |
33 |
35 |
49 |
55 |
Misleading question |
|
X |
|
|||||||
Indexing omission |
X |
|
X |
|
|
X |
|
X |
X |
X |
Faulty search |
|
|
X |
X |
|
|||||
Search too specific |
|
X |
|
X |
|
|||||
Schedule inadequacy |
|
X |
|
X |
|
|
Question numbers |
|||||||||
|
56 |
60 |
65 |
72 |
76 |
84 |
86 |
87 |
96 |
97 |
Indexing omission |
X |
X |
X |
|
X |
X |
X |
X |
|
X |
Search too specific |
X |
|
X |
|
||||||
Clerical error in posting |
|
X |
|
(e) Summary. A total of all the above single or contributory causes of complete or partial failure may be helpful in pinpointing the chief weaknesses of the system.
Semantics |
||
Misleading question |
3 |
|
Question insufficiently specific |
2 |
|
Question misinterpreted |
3 |
8 |
Input stage |
||
Indexing omission |
34 |
|
Schedule inadequacy |
6 |
|
Clerical error |
1 |
41 |
Output stage |
||
Faulty search |
2 |
|
Search too specific |
4 |
6 |
Total |
|
55 |
It will be noted that the largest single factor was indexing omission, and this in turn is believed to be attributable mainly to lack of subject knowledge. Next largest is the “semantics” group, failure in communication between the questioner and the searcher.
The six cases of schedule inadequacy, together with other omissions noted in indexing the first 700 documents, will lead to minor revision of the classification. At this time, reconsideration will be given to the necessity for retaining some headings which have hardly been used at all, and others which have
been used so often as to render them almost useless for retrieval purposes.
The six cases of failure at the output stage are not considered significant: none persisted beyond a first search, and with peek-a-boo it is possible to make several searches in a few minutes.
NUMBER OF CODES USED IN INDEXING
Average number of codes used in indexing 700 documents |
28.96 |
Average number of codes used in indexing the 54 documents successfully retrieved at the first search |
30.59 |
Average number of codes used in indexing the 15 documents which could not be retrieved |
30.07 |
Indexer A used an average of 30.50 codes for each report. Indexer B used an average of 32.94 codes for each report. Indexers C−F used an average of 29.12 codes for each report. |
All these averages, except the first figure of 28.96, are based only on the 100 documents on which questions were asked.
ANALYSIS BY INDEXER
All indexers used about the same average number of codes per document, but the success achieved varied with the indexer’s subject knowledge. Indexer A was in charge of a specialised library for aerodynamicists; B, in charge of a more general aeronautical library, had considerable experience in aviation and in library services; C to F had served in aeronautical libraries for periods varying from 5 years to only a few months.
RELEVANCE OF DOCUMENTS RETRIEVED
In the N.L.L. tests (3, 4) searchers were able to make a rough assessment of the relevance of each document retrieved by an examination of the detailed information printed on the N.L.L. punched cards. In the present case it would have been necessary to refer each document, or an abstract of it, to the questioner. This being a time-consuming operation, it was decided to do so only on a sample of 20 successfully answered questions. These were further restricted to cases in which 3 to 12 documents had been thrown up in the retrieval process. In 20 cases, therefore, questioners were presented with abstract cards or documents and they decided whether the documents retrieved, in addition to the ones on which their questions were based, were truly relevant in terms of their questions as set.
Total documents retrieved for the 20 questions came to 146 (the number of aspect cards correlated varied from 1 to 5, but was usually between 2 and 4). It was found that 70 documents were relevant, 18 were of marginal relevance, and 58 were irrelevant. This makes a broad ratio of 3.5:1:3, which appears to be satisfactory, although it is clearly desirable to reduce the marginally relevant figure. This can probably be achieved by improved indexing.
Time studies
INPUT
Accurate time studies were made of three main aspects of the input stage of this project. These were: times taken to index each document, times taken to post code numbers to a ledger, and times taken to transfer this information to punched Hollerith cards.
-
Time to index documents. Indexer A, who was responsible for half of all indexing, timed himself on 17 occasions. This was done only after considerable experience of indexing difficulties and detailed knowledge of the schedules had been gained. 153 documents were indexed in 31 hours 5 minutes, which gives 13.5 minutes per document.
-
Time to post index numbers. All papers indexed had their codes recorded on the card described in “Procedure” under “Indexing.” These codes were
-
then transferred to a plain ledger to facilitate eventual punching. In 18 operations, codes for 474 documents were posted by 2 persons in 19 hours 16 minutes, which gives 2.4 minutes per document.
-
Time to punch Hollerith cards. Codes for 500 documents were transferred from the ledger and punched on Hollerith cards in 19 hours 30 minutes. This was done in 12 operations by 2 persons, at an average of 2.34 minutes per document.
Total times for each document subject-indexed by the system described therefore consist of 13.5 minutes for indexing, 2.4×2 minutes for posting, and 2.34×2 minutes for punching, or 22.98 minutes. These are the three time-expensive parts of the programme, but, if an allowance of 5 minutes for extracting or filing papers or associated clerical processes is made, it is reasonable to assess inclusive time for subject indexing and all allied clerical effort as an average of 28 minutes per document. Half of this is relatively expensive indexing. No great reduction in any of these times can be expected.
OUTPUT
The output stage of this system consists firstly in relating a question to the classification schedules, in carefully assessing the best aspect cards to be used,1 in correlating these cards and reading the holes punched all through. With practice, these were found to be rapid processes which, depending on the complexity of the question, could be performed within 2–10 minutes. The second phase consists of removing the relevant serially numbered abstract cards from the file, and offering them to the questioner, who may then wish to see some of the actual documents represented by the cards. The total output stage should not normally exceed 15–20 minutes.
Conclusions
The combination of subject classification and peek-a-boo appears to have many advantages as a means for the analytical indexing of documents in a well-defined subject such as aerodynamics. There would appear to be a market for the commercial development of “miniaturised” cards or plates having a capacity of 20,000 or more positions and of appropriate punching and viewing equipment.
1 |
Bernier (5) has found, theoretically, that “discovery of unexpected documents by use of a manipulative, correlative index is usually highly improbable if the number of terms taken at a time in searching is four or more….” It was found, as described in the paragraph on relevance of documents retrieved, that the number of peek-a-boo cards correlated usually fell within the range 2–5. |
Best results have been obtained by indexers with subject knowledge, and “production” indexing should be undertaken only by such indexers.
The classification used was basically sound, but requires expansion in some areas and contraction in rather more, so as to achieve less variation in the number of times code-numbers are used. In many cases scope notes are required.
A survey (6) of the report literature actually in use by a typical group of aerodynamicists shows that 98% of the reports were less than 10 years old and 83% less than 5 years old. This finding is likely to influence schedule revision and may necessitate re-appraisal of the scope of the present project. It also tends to minimise one criticism of peek-a-boo, i.e., that it is necessary at intervals, depending on card capacity and accession rate, to start a completely new index.
REFERENCES
1. WILDHACK, W.A., STERN, J., SMITH, J., Documentation in instrumentation. American Documentation 5, 223–237 (1954).
2. CLEVERDON, C.W., THORNE, R.G., A brief experiment with the Uniterm system of co-ordinate indexing for the cataloguing of structural data (unpublished).
3. VESSEY, H.F., Test of N.L.L. card catalogue of aerodynamic measurements (unpublished).
4. VESSEY, H.F., SEYMOUR, J.R., Test of N.L.L. card catalogue of aerodynamic measurements. II (unpublished).
5. BERNIER, C.L., Correlative indexes and the blank sort. American Documentation 9, 32–41 (1958).
6. WILSON, C.W.J., Report literature used by aerodynamicists (unpublished).
TABLE 1 The 100 questions and the searches based on them
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
1 |
Effect of incidence on pressures recorded on a Hunter aircraft. |
(a) 365 362 (Hunter) |
(a) 14 |
B |
21 |
B |
F |
Peek-a-boo cards for aircraft names are not yet available, but would normally be used. In this case neither “Hunter” nor “365-Incidence” was indexed. |
|
|
(b) 365 417 362 |
(b) 1 |
|
|
A |
F |
Searcher B misunderstood the question as relating to aerodynamic pressures: document related to pitot-static tube pressures. “Pitot static tubes” had been noted by indexer as a desirable new heading. |
2 |
Aerodynamics of struts |
349 264 |
10 |
C |
36 |
A |
S |
|
3 |
Spinning tunnel instrumentation |
397 417 |
1 |
B |
22 |
A |
S |
|
4 |
Early methods of measuring rates of climb (relative merits of barograph and cinematograph) |
(a) 417 369 378 |
(a) 0 |
A |
26 |
B |
F |
“417-Instruments” not indexed. |
|
|
(b) 369 378 |
(b) 14 |
|
|
B |
S |
|
5 |
Applications of the Ludwig-Tillman skin friction formula |
(a) 128,137 136,154 349,352 |
(a) 4 |
A |
28 |
A |
F |
Indexers had noted skin friction as a necessary new indexing term. |
|
|
(b) 113,128 137,352 |
(b) 12 |
|
|
A |
S |
|
6 |
Effect of rate of approach to a stall on the stall CL |
365 350 |
26 |
B |
47 |
B |
S |
378, if used, would reduce the number of documents to 3. |
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
7 |
Transient analysis techniques of frequency response measurement using pulse type inputs (assessment of use) |
(a) 373 |
(a) 48 |
A |
23 |
A |
F |
Subject document discussed dynamics of helicopter rotor control systems. |
|
(b) 417 391 416 |
(b) 2 |
|
|
B |
F |
|
|
8 |
Correlation of theory and experiment pressure distributions around swept wings at high subsonic Mach numbers |
362 206 125 123 |
20 |
C |
26 |
B |
S |
|
9 |
Effects of wing dihedral on lateral stability |
195 232 355 357 |
3 |
A |
35 |
A |
S |
|
10 |
Creep of turbine blades |
327 386 |
4 |
A |
18 |
B |
S |
|
11 |
How can the exhaust fumes from an aero-engine be dispersed when doing full-scale tests in a closed circuit wind tunnel? |
(a) 326 339 392 391 |
3 |
A |
29 |
B |
F |
“377-Ventilation” might well have formed part of the search plan. |
|
|
(b) 339 392,391 |
13 |
|
|
B |
S |
“326-Engine” not indexed. |
12 |
What is the effect of endplates (tip fins) on lift slope and pitching moment of a straight wing at high subsonic Mach numbers? |
(a) 112,123 195,196 205,302 320,235 132 |
0 |
D |
30 |
A |
F |
Indexing omissions. Not indexed under end-plates, wing, monoplane, or interest-at-wing-tip. |
|
|
(b) 320,358 123,125 |
6 |
|
|
A |
F |
|
13 |
What is the effect of movement of C.G. position on spinning characteristics of aircraft of conventional layout and unswept wings? |
193 195 205 251 |
6 |
F |
24 |
A |
S |
|
14 |
What will be the effect of the tip vortices from the main wings on the tail surfaces of a cruciform-winged missile with indexed cruciform controls? |
143 198 164 |
5 |
A |
37 |
B |
S |
|
15 |
At sonic or supersonic speeds, what is the load distribution on a cropped delta wing with a specified twist distribution across the span? |
122 195 203 363 |
14 |
C |
26 |
A |
S |
|
16 |
What is the effect of surface roughness on the drag of an aircraft? |
341 352 339 193 |
2 |
F |
28 |
B |
S |
|
17 |
What information exists on methods of reducing the landing run of high speed aircraft? |
(a) 193 367 377 |
(a) 15 |
B |
34 |
A |
F |
|
|
|
(b) 193 367 |
(b) 38 |
|
|
A |
P |
“377-Operation/Design” not coded, but its division “378-Performance” was coded. Indexing omission. |
18 |
How can aerodynamic derivatives due to yawing motion be measured in a wind tunnel? |
359 392 417 |
4 |
A |
35 |
B |
S |
|
19 |
Does the nature of the surface terrain significantly affect the pattern of gusts encountered by an aircraft? |
153 377 |
4 |
A |
24 |
A |
S |
|
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
20 |
What is the best speed to fly a sailplane in soaring conditions for various lift/drag ratios and thermal strengths? |
178 419 |
1 |
A |
13 |
B |
S |
|
21 |
Theoretical analysis of cranked wings. |
113 195 204 |
3 |
A |
27 |
B |
S |
|
22 |
Hot wire amplifiers. |
(a) 388 411 417 |
3 |
A |
19 |
A |
F |
|
|
|
(b) 388 417 |
8 |
|
|
A |
S |
|
23 |
Wind tunnel facilities at Arnold Engineering Development Centre, Tullahoma. |
391 392 |
74 |
C |
35 |
A |
P |
Use of “112-Experiment” reduces to 66 documents, but this type of question is better answered by use of conventional index. The code “115-USA” was to be used only for documents originating in the U.S. but might have been appropriate in this case. |
24 |
Pressure distribution on fuselage at supersonic speeds. |
362 240 122 |
42 |
B |
28 |
B |
P |
Insufficiently specific question to narrow the search further. 6% of the lection may well be relevant to the question. |
25 |
Calculation of biplane lift at subsonic speeds. |
(a) 113 197 350 125 |
0 |
A |
28 |
B |
F |
|
|
|
(b) 113 197 |
2 |
|
|
B |
S |
The subject document actually discusses possibilities of a biplane for supersonic flight. |
26 |
Separated flow: theoretical treatment. |
(a) 113 142 |
(a) 12 |
C |
17 |
B |
F |
“113-Theory” not coded. |
|
|
(b) 113 142 128 |
(b) 12 |
|
|
A |
F |
“142-Separation” alone is successful, but produces 36 documents. |
|
|
(c) 142 |
(c) 36 |
|
|
B |
P |
|
27 |
Wind tunnel tests on X-1E aircraft. |
(a) Aircraft names |
|
A |
32 |
A |
S |
(a) Aircraft names index has not yet been transferred to peek-a-boo, but would obviously be successful. |
|
|
(b) 112 115 390 392 |
(b) 5 |
|
|
A |
F |
(b) Failure due to clerical error. 392 was indexed but not punched. |
|
|
(c) 112 115 390 |
(c) 12 |
|
|
A |
S |
|
28 |
Shock wave interaction. |
(a) 148 364 |
(a) 8 |
A |
18 |
B |
F |
|
|
|
(b) 148 |
76 |
|
|
B |
P |
“364-Interference/relative position” not indexed. |
29 |
Downwash behind delta wing. Subsonic speeds. |
125 144 203 |
11 |
A |
42 |
A |
S |
|
30 |
Mechanical design of flexible walls for wind tunnels. |
408 391 387 392 |
1 |
C |
35 |
B |
S |
|
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
31 |
What data are available on gust loads and their alleviation? |
(a) 153 363 419 |
2 |
A |
12 |
B |
F |
|
|
|
(b) 153 419 |
4 |
|
|
B |
S |
“363-Loads” not indexed. |
32 |
Data required on the drag of struts, effect of section shape, fineness ratio, etc. |
(a) 264 352 |
4 |
A |
37 |
A |
F |
“264-Strut mounted” not indexed, and the schedules do not provide for struts themselves. |
|
|
(b) 227 247 or 248 352 |
0 |
|
|
B |
F |
|
33 |
What information is available on the drag penalty of various radiator schemes? |
(a) 352 155 |
6 |
A |
28 |
B |
F |
Radiator cannot be expressed in the existing schedules. |
|
|
(b) 352 326 |
15 |
|
|
B |
S |
|
34 |
Are there any flight data on the measurement of control panel deflections? |
(a) 405 302 363 |
0 |
F |
23 |
B |
F |
The subject document describes only wind tunnel experiments. |
|
|
(b) 406 302 363 |
1 |
|
|
B |
F |
“302-control device” not indexed. |
35 |
What flight experience is available on the effect of drop tanks (strut or tip) on performance? |
(a) 112, 259 261, 274 339, 405 378 |
(a) 0. |
A |
47 |
A |
F |
|
|
|
(b) 112 259, 261 |
(b) 5 |
|
|
A |
S |
|
36 |
How does wing tip shape affect the wave drag (tunnel data required). |
(a) 392 235 352 222 |
7 |
E |
41 |
B |
F |
“235-tip” not indexed. |
|
|
(b) 112, 195 235, 352 |
12 |
|
|
A |
F |
|
37 |
Has any flight work been done with an aircraft fitted with a castoring undercarriage? |
(a) 280 |
9 |
F |
32 |
A |
F |
“280-Undercarriage” not indexed. |
|
(b) 112, 139, 367 |
2 |
|
|
A |
F |
|
|
|
|
(c) 112, 405, 367 |
14 |
|
|
A |
S |
|
38 |
General information on seaplane tank techniques. |
402 |
12 |
B |
24 |
B |
S |
No co-relation necessary. Conventional index would serve just as well. |
39 |
What is the effect of body cross-section shape on the isolated body moments in pitch and yaw? |
(a) 240, 257 354, 358 359 |
1 |
A |
40 |
A |
F |
The combination 240, 354 would have been successful, but with 39 other documents retrieved. |
|
|
(b) 358, 359, 354 240 |
10 |
|
|
B |
F |
“359-directional” and “257-section” not indexed. |
40 |
What information is there on the use of spoilers for providing roll control at transonic and supersonic speeds? |
(a) 319 356 357 122 |
3 |
A |
25 |
B |
F |
“319-spoilers” and “356-control” not indexed. |
41 |
The variation in hinge moment at low speeds due to flap angle, for a simple split flap near the half semi span position and close to the trailing edge. Wind tunnel results. |
(a) 112 126, 317 354, 360 |
1 |
F |
31 |
A |
F |
|
|
(b) 392, 317 354, 360 |
1 |
|
|
B |
F |
|
|
|
(c) 317, 392 |
12 |
|
|
B |
S |
Hinge moments (354, 360) not indexed. |
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
42 |
Number of fatal accidents caused by fire in an aircraft during flight on American domestic airlines. |
159 382 |
6 |
A |
11 |
A |
S |
|
43 |
Method for deducing suitable cross-sectional area distributions for a narrow delta wing (unswept trailing edge) for low zero-lift wave drag. |
203 148 |
6 |
E |
24 |
B |
S |
“229-thickness” would further reduce to 3 documents. |
44 |
The jettison characteristics at low speed of a Blue Jay mounted on pylons under the wing of an aircraft. |
371 164 |
2 |
A |
36 |
B |
S |
Peek-a-boo cards representing proper names of aircraft, missiles, etc., have not yet been prepared, but would be used in practice in this case. |
45 |
Longitudinal dynamic stability derivatives of a simple infra-red homing missile configuration, between M=0.7 to 1.4. |
123, 124 164, 355 358 |
5 |
A |
45 |
A |
S |
|
46 |
Theoretical estimation of wave drag at supersonic speeds of a slender body of elliptic cross-section with discontinuities in profile slope. |
352 122 240 254 |
6 |
A |
29 |
B |
S |
|
47 |
The calculation of spanwise loading for an unswept uncambered oscillating wing by a “lifting line” technique. |
(a) 195 205, 363 |
25 |
A |
24 |
A |
S |
|
48 |
A method for estimating the |
(a) 363, 386 |
10 |
A |
12 |
A |
F |
|
|
buckling load of flat sandwich panels, with the loading edges rigidly clamped. |
(b) 109, 386 |
3 |
|
|
A |
F |
“363-Loading” not indexed. |
|
(c) 113, 386 |
17 |
|
|
A |
S |
|
|
49 |
An assessment of the jet flap aerofoil as a practical means of control for an aircraft. |
(a) 145 302, 318 |
3 |
C |
38 |
A |
F |
|
|
(b) 325 |
10 |
|
|
A |
S |
“145-Jets” and “318-Other flap” not indexed. |
|
50 |
A method of reducing heat transfer to blunt bodies by air injection. |
154 240 243 347 |
1 |
A |
31 |
B |
S |
|
51 |
How can the thrust and torque of a windmill be calculated? |
327 353 |
3 |
A |
17 |
A |
F |
Paper is on autogyros. “327-Windmill” not indexed. |
52 |
Experimental data on variation of heat transfer coefficient round the front of a hemisphere at high Mach numbers. |
112, 120 154, 240 243, 255 |
2 |
A |
28 |
A |
S |
|
53 |
What methods are available for estimating the effect of incidence on the yawing moment due to sideslip at high supersonic speeds? |
(a) 120 354 359 366 |
4 |
A |
37 |
B |
F |
“354-moments” and 366-sideslip” not indexed. |
|
|
(b) 122 354, 359 365, 366 |
0 |
|
|
A |
F |
|
54 |
Is there any information on the conditions leading to “intake buzz?” |
285 136 148 |
11 |
F |
27 |
B |
S |
|
55 |
Methods for calculating the total pressure loss behind an aerofoil at low speeds. |
(a) 109 126, 195 |
14 |
A |
22 |
A |
F |
“109-Method for calculation” not indexed. |
|
(b) 126 |
195, 144 25 |
|
|
A |
S |
|
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
56 |
Comparisons between flight and wind tunnel tests of the lift increment due to flaps with blowing. |
(a) 112, 305 306, 315 |
2 |
F |
45 |
A |
F |
|
|
(b) 112 146, 315 |
2 |
|
|
A |
S |
|
|
57 |
What methods are available for calculating the loading due to aileron deflection on a swept wing? |
(a) 109 206 363 |
5 |
F |
20 |
A |
F |
“206-swept” not indexed. Subject document did not relate specifically to swept wings. |
|
(b) 206, 363 |
35 |
|
|
B |
F |
“363-loading” not indexed. |
|
58 |
What machine aids were used in World War II for stability and control calculations? |
355 356 389 |
5 |
C |
20 |
B |
S |
|
59 |
List available design studies of supersonic aircraft. |
122 193, 377 |
12 |
B |
45 |
A |
S |
|
60 |
What information is available on the normal force/incidence curve of bodies of revolution at incidences above 20° and speeds near Mach 2? |
(a) 253 121, 124 365 |
0 |
B |
40 |
B |
F |
“365-High incidence” not indexed. |
|
(b) 253 121, 124 392 |
14 |
|
|
B |
S |
||
61 |
The effectiveness of different types of roughness in thickening turbulent boundary layers at various free-stream Mach numbers. |
(a) 137 140, 341 |
5 |
A |
24 |
A |
F |
|
|
(b) 137, 140 |
38 |
|
|
A |
P |
“341-Surface condition” not indexed. |
|
62 |
The effects of the temperature and quantity of bleed flow on base pressure at supersonic speed. |
122, 240 256 362 |
11 |
A |
46 |
A |
S |
|
63 |
The effects of side-support struts on the base pressure of a model at supersonic speeds. |
392 122 362, 240 256 |
6 |
A |
32 |
B |
S |
|
64 |
Is external stream speed important in estimating the performance of ejector jet nozzles? |
286 297 145 |
3 |
A |
37 |
B |
S |
|
65 |
The best position at which to put distributed roughness on a model in order to stimulate boundary layer transition to turbulent flow. |
(a) 122, 128 137, 141 340, 341 |
4 |
A |
27 |
A |
F |
|
|
(b) 112, 137 141, 341 |
6 |
|
|
A |
S |
|
|
66 |
Afterbody pressures on bodies of revolution, with and without wings or fins, in supersonic flight. |
(a) 122, 240 253, 256 362 |
10 |
A |
41 |
A |
F |
“Afterbody” cannot neatly be expressed in the schedule. |
|
|
(b) 122 256, 253 |
11 |
|
|
B |
F |
“256-interest near the tail” not indexed. |
67 |
The extension of aerofoil theory to wings whose lift is not solely dependent on incidence. |
(a) 113, 195 |
112 |
A |
49 |
A |
P |
In (a) and (b) searcher failed to recognise jet flap. |
|
(b) 113, 195 349, 350 |
40 |
|
|
A |
P |
||
|
|
(c) 113, 195 349, 350 145 |
2 |
|
|
A |
S |
|
68 |
Criteria determining the length of a finite region of a separated laminar boundary layer in two-dimensional flow. |
142 139 137 |
10 |
B |
32 |
B |
S |
|
69 |
The response time of a pressure measuring system embodying long tubes. |
417 362 284 |
6 |
E |
25 |
B |
S |
|
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
70 |
The ram efficiency of air intakes let into the sides of a wing or body. |
(a) 281 282, 285 |
13 |
B |
42 |
A |
F |
“282-Located on aerofoils” not indexed. |
|
(b) 281, 285 |
40 |
|
|
A |
P |
|
|
71 |
Is the temperature recovery factor of a laminar boundary layer altered by separation of the boundary layer? |
137 139 142 |
10 |
A |
27 |
A |
S |
|
72 |
Data required from tests employing the NACA Technique for obtaining free-flight stability data from models fitted with an all-moving tailplane which moves automatically between stops under the influence of the aerodynamic forces on it. |
(a) 112, 115 117, 338 406 |
0 |
A |
46 |
A |
F |
|
|
(b) 115, 117 406 |
8 |
|
|
A |
S |
|
|
73 |
For assisted take-off, what are the advantages of a liquid fuel rocket over a solid fuel rocket? |
171 271 377 |
3 |
B |
32 |
B |
S |
|
74 |
What are the handling qualities of the Javelin aircraft at high lift coefficients? |
350 378 |
17 |
B |
38 |
B |
S |
The 17 documents will be reduced substantially when the name Javelin (used in indexing) has been represented by a peek-a-boo card. |
75 |
What reports from the Royal Aircraft Factory appeared during the 1914–18 war on aircraft stability theory. |
100, 113 114, 117 349, 355 |
1 |
A |
15 |
A |
S |
|
76 |
To what extent may disturbances present in a wind tunnel invali |
(a) 125, 137 141, 195 |
12 |
B |
30 |
A |
F |
|
|
date tests made in the tunnel to locate the position of boundary layer transition on a wing at subsonic speeds? |
(b) 112, 137 141, 195 392 |
11 |
|
|
A |
S |
Indexer omitted to index Mach numbers. |
77 |
What changes in piloting technique are necessary for the safe landing of an aircraft without an undercarriage on an aircraft carrier adapted to receive it? |
331 367 |
4 |
F |
21 |
A |
S |
|
78 |
Can Falkner’s 9-point method (for calculating the aerodynamic loading on a wing) be simplified for application to a swept wing of low aspect ratio? |
113 368 195 206 212 |
5 |
E |
33 |
B |
S |
|
79 |
A method is required for calculating the spanwise distribution of lift on a wing of low aspect ratio at high subsonic speeds, including allowance for the non-linear variation of lift with incidence. |
350 362 212 125 123 113 |
2 |
A |
35 |
B |
S |
|
80 |
Wanted: a good theoretical treatment of the downwash field behind a low aspect ratio wing including the behaviour of the tip vortices at supersonic speeds. |
113 144 122 143 |
6 |
A |
24 |
B |
S |
|
81 |
Information is required on numerical methods employed in the theoretical determination of the drag of a slender body of arbitrary cross-section. |
113 240 352 |
14 |
A |
16 |
A |
F |
“240-body” not indexed. Paper was on area rule, which was indexed. |
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
82 |
What methods have been tried in flight to improve the damping of lateral oscillation of high-speed aircraft? |
112, 193 339, 355 357, 373 405 |
2 |
A |
33 |
A |
S |
|
83 |
Have we any experimental measurements of the influence of aero-elastic distortion on the effectiveness of trailing edge flaps on rectangular wings? |
112 374 315 308 |
3 |
A |
38 |
B |
S |
|
84 |
What reports give design charts for the determination of the downwash angle at the tailplane for tapered wing planforms with plain flaps at low speeds. |
(a) 144, 126 315, 202 |
2 |
A |
50 |
B |
F |
“202-tapered” not indexed |
|
(b) 144, 126 315 |
11 |
|
|
B |
S |
|
|
85 |
Approximate methods to suggest the requirements of an auto-control system for the control of the “long period” or “phugoid” motion of an aircraft. |
278 373 |
9 |
A |
16 |
A |
S |
|
86 |
Experimental measurements at supersonic speeds of the flow field in the vicinity of a body of revolution at high angle of incidence. |
(a) 112, 122 253, 365 |
0 |
A |
39 |
B |
F |
“365-high incidence” not indexed. |
|
(b) 112, 122 253, 128 |
34 |
|
|
B |
S |
|
|
87 |
Calculations to indicate the effect of introducing inertia |
(a) 109, 302 356, 358 |
4 |
C |
25 |
A |
F |
|
|
weights and springs into a power-operated control system for the longitudinal control of an aircraft. |
(b) 278, 302 355, 358 |
7 |
|
|
A |
S |
|
88 |
Experimental data on the effects of slipstream on tailplane effectiveness at high subsonic |
(a) 112, 144 236, 358 125, 123 |
5 |
A |
43 |
B |
F |
The abstract card, issued with one of the 5 documents, refers to the subject document. Mach numbers. |
|
(b) 112, 123 144, 236 |
10 |
|
|
A |
F |
“144-slipstreams” and “236-tail-plane” not indexed. |
|
89 |
Experimental determination of the relationships between turbulent boundary layers on flat plates and cones at zero heat transfer. |
112 140 137 333 |
11 |
A |
35 |
B |
S |
|
90 |
Experimental measurements at high subsonic speeds of the pressure distribution over the leading edge of a two-dimensional flat plate with a rounded leading edge. |
112 125 333 362 |
4 |
A |
31 |
A |
S |
|
91 |
Wind tunnel tests at supersonic speeds on a canard configuration with ramjets. |
112, 122 172, 192 392 |
1 |
A |
54 |
A |
S |
|
92 |
Manometers for automatic measurement of pressures in supersonic wind tunnels. |
122, 362 391, 392 417 |
4 |
B |
23 |
A |
S |
|
93 |
The effect of small asymmetries at the nose of a cylindrical body at supersonic speeds. |
(a) 240, 249. 122, 255 |
3 |
C |
37 |
B |
F |
“249-straight parallel sides,” and “255-interest at nose” not indexed. |
|
(b) 240 249, 122 |
43 |
|
|
B |
F |
|
|
|
(c) 122 |
240, 255 |
10 |
|
|
A |
F |
|
Question No. |
Question |
Search plan |
Documents retrieved |
Indexer |
Codes used |
Searcher |
Success or failure |
Remarks |
94 |
Theoretical methods for determining the performance of wing-tip controls. |
113, 302 307, 322 |
3 |
B |
35 |
A |
S |
|
95 |
Any information on moving-wing guided missiles. |
164, 322 195 |
5 |
A |
49 |
B |
S |
|
96 |
Wind tunnel tests at supersonic speeds on two-dimensional aerofoils. |
(a) 112 122, 195 338, 392 |
7 |
B |
34 |
A |
F |
“392-wind tunnels” was indexed but not punched. |
|
(b) 112, 122 |
195, 338 |
10 |
|
|
A |
S |
|
97 |
Rapid recording methods for measuring signals from strain gauge wind tunnel balances. |
(a) 417, 413 391, 416 |
0 |
A |
18 |
B |
F |
“413-balances” not indexed. |
|
(b) 391 416, 417 |
2 |
|
|
B |
S |
|
|
98 |
Design of a six-component strain gauge balance for use in supersonic wind tunnels. |
392, 391 413, 122 |
5 |
A |
23 |
B |
S |
|
99 |
Flow at supersonic speeds over bodies of non-circular cross-section. |
240, 254 122, 128 |
11 |
A |
27 |
B |
S |
|
100 |
Experimental information about the lift on wings at hypersonic speeds. |
112, 120 195, 350 |
10 |
A |
40 |
A |
S |
|
TABLE 2 Classification schedules
|
Code No. |
Timesa used |
Bibliographic characteristics |
||
Pre 1935 |
100 |
77 |
“ 1945 |
101 |
149 |
“ 1950 |
102 |
194 |
“ 1955 |
103 |
500 |
Post 1934 |
104 |
633 |
“ 1944 |
105 |
555 |
“ 1949 |
106 |
505 |
“ 1954 |
107 |
192 |
Data/Tables/Methods; for Calculation/Reference |
109 |
58 |
Bibliography/Survey |
110 |
18 |
Dictionary/Directory/ Nomenclature |
111 |
0 |
“Experiment”/Reports observation |
112 |
524 |
“Theory”/Other |
113 |
230 |
G.B. |
114 |
493 |
U.S.A. |
115 |
203 |
Other foreign/ International |
116 |
3 |
RAE/NACA/AGARD |
117 |
621 |
Firms |
118 |
3 |
Other |
119 |
77 |
Mach number/velocity |
||
≥2.0 |
120 |
107 |
≥1.2 |
121 |
176 |
≥0.9 |
122 |
253 |
≥0.6 |
123 |
280 |
<2.0 |
124 |
393 |
<1.0 |
125 |
324 |
<0.6 |
126 |
236 |
Stationary |
127 |
12 |
Flow/Fluids studied |
128 |
359 |
Ideal fluid |
129 |
20 |
Gas |
130 |
328 |
Liquid |
131 |
18 |
Real fluids other than Air/Water (including Rare air/Slip flow, etc.) |
132 |
8 |
Homogeneous fluid/Total immersion |
133 |
8 |
Other/Free surface/ Mixed flow |
134 |
38 |
In own right |
135 |
26 |
In relation to solids |
136 |
279 |
Boundary Layer |
137 |
94 |
Flow/Fluids studied |
||
Other |
138 |
27 |
Laminar/Streamline flow |
139 |
51 |
Turbulent flow |
140 |
59 |
Transition |
141 |
42 |
Separation |
142 |
36 |
Vortices |
143 |
45 |
Slipstreams/Wakes/ Downwash |
144 |
89 |
Jets |
145 |
27 |
Blowing |
146 |
16 |
Suction |
147 |
28 |
Shock waves/Mach lines/ Compressibility |
148 |
76 |
Circulation |
149 |
4 |
Condensation/Evaporation |
150 |
4 |
Convection |
151 |
5 |
Dissociation |
152 |
1 |
Gusts |
153 |
16 |
Heating |
154 |
41 |
Cooling |
155 |
28 |
Acoustics/Noise/Sonic bangs |
156 |
6 |
Aircraft/Aircraft components Aircraft “Type” |
||
Fighter |
157 |
117 |
Bomber |
158 |
38 |
Transport |
159 |
22 |
Personal |
160 |
8 |
Other |
390 |
38 |
Shell |
161 |
1 |
Bomb |
162 |
12 |
Target |
163 |
3 |
“Missile” |
164 |
47 |
“Single” engined |
167 |
90 |
Multiple engined |
168 |
67 |
Jet propelled |
169 |
146 |
Turbojet |
170 |
90 |
Rocket |
171 |
33 |
Other/Ram, pulse |
172 |
18 |
Propeller driven |
173 |
85 |
Turbo prop |
174 |
21 |
Other |
175 |
24 |
Rotary wing aircraft |
176 |
23 |
Towed |
177 |
7 |
Sailplane |
178 |
7 |
Lighter than air |
179 |
3 |
Kite |
180 |
3 |
a Times used in the indexing of 700 documents. |
|
Code No. |
Timesa used |
Aircraft/Aircraft components |
||
Aircraft “type” |
||
Parachute |
181 |
6 |
Other method of propulsion |
182 |
0 |
Seaplane |
183 |
16 |
Amphibian |
184 |
1 |
V.T.O. Type/Flying platform, etc. (not helicopters) |
185 |
4 |
Composite aircraft |
186 |
0 |
No wing |
187 |
14 |
No body |
188 |
5 |
No tailplane/No foreplane |
189 |
50 |
No fin |
108 |
20 |
With multiple fuselage |
190 |
8 |
With fins other than single tail fin |
191 |
15 |
With foreplane/Canard |
192 |
6 |
Components present and/or studied |
||
Complete aircraft |
193 |
286 |
Other |
194 |
324 |
Wing |
195 |
361 |
Monoplane |
196 |
229 |
Biplane |
197 |
16 |
Cruciform, Y, etc. |
198 |
26 |
Other |
199 |
1 |
Untapered |
201 |
57 |
Tapered excluding delta, arrow |
202 |
67 |
Triangular/Delta/Arrow |
203 |
104 |
Other (circular, “W,” etc.) |
204 |
6 |
Unswept (inc. 10° sweepback) |
205 |
102 |
Swept |
206 |
177 |
Forward |
207 |
2 |
<40° |
208 |
45 |
≥40° |
209 |
108 |
<50° |
210 |
87 |
≥50° |
211 |
43 |
Aspect ratio <4 |
212 |
89 |
Aspect ratio ≥3.5 |
213 |
67 |
Aspect ratio ≥6 |
214 |
18 |
Leading edge sharp |
215 |
15 |
Wing |
||
Leading edge ducted |
216 |
5 |
Leading edge drooped |
217 |
3 |
Cambered |
218 |
25 |
Uncambered |
219 |
11 |
≥8% thick |
220 |
56 |
<8% thick |
221 |
42 |
Interest in/at/near—wings |
||
Planform |
222 |
89 |
Aspect ratio |
223 |
28 |
Sweep |
224 |
37 |
Taper |
225 |
19 |
Other/span |
226 |
25 |
Section |
227 |
63 |
Camber |
228 |
25 |
Thickness |
229 |
34 |
Other/profile |
230 |
35 |
Twist |
231 |
22 |
Dihedral/anhedral |
232 |
4 |
Leading edge |
233 |
42 |
Trailing edge |
234 |
61 |
Tip |
235 |
42 |
Tailplane/Foreplane |
236 |
79 |
Fin |
237 |
35 |
Propeller |
238 |
32 |
Rotor |
239 |
22 |
Body |
240 |
139 |
Pointed nose |
241 |
74 |
Other nose |
243 |
24 |
Pointed tail |
244 |
18 |
Other tail |
246 |
54 |
Fineness Ratio ≥6 |
247 |
43 |
Fineness Ratio <6 |
248 |
15 |
Straight parallel sides |
249 |
58 |
Other |
250 |
42 |
Rotationally symmetric/ Body of revolution |
253 |
80 |
Other |
254 |
23 |
Interest in/at/near—Bodies |
||
Nose |
255 |
17 |
Tail |
256 |
29 |
Section |
257 |
10 |
Sides |
258 |
18 |
a Times used in the indexing of 700 documents. |
|
Code No. |
Timesa used |
External store |
259 |
38 |
Engine nacelle |
260 |
32 |
Other |
261 |
7 |
Wing mounted |
262 |
26 |
Other |
263 |
7 |
Strut mounted |
264 |
11 |
Other |
265 |
6 |
Canopy/Radome/Turret/ “Blister” |
266 |
8 |
Bomb bay/Release gear |
267 |
6 |
Guns/Armament |
268 |
19 |
Escape device |
269 |
2 |
Aerial/Antennas |
270 |
2 |
Assisted take-off device |
271 |
7 |
De-icing gear/Icing |
272 |
4 |
Fuel/Fuel system |
273 |
3 |
Fuel tank |
274 |
12 |
Crew accommodation |
275 |
2 |
Load/Passenger accommodation |
276 |
3 |
Dirt excluders/Ventilation |
277 |
5 |
Automatic control/ Servomechanisms/ Stabilization |
278 |
31 |
Float/Planing surface |
279 |
12 |
Undercarriage—Land |
280 |
9 |
Internal flow |
281 |
96 |
Located on aerofoils |
282 |
26 |
Located on bodies, nacelles |
283 |
34 |
Other/pipes |
284 |
30 |
Intakes (divide as exits) |
285 |
51 |
Exits |
286 |
20 |
Nose/Tail |
287 |
23 |
Side |
288 |
11 |
With centre-body |
291 |
21 |
No centre-body |
292 |
9 |
Ducts |
293 |
47 |
Straight sections |
294 |
3 |
Bends |
295 |
2 |
Contractions/ Expansions |
296 |
20 |
Nozzles |
297 |
21 |
Diffusers |
298 |
18 |
Other |
299 |
1 |
Convergence/ Divergences |
300 |
4 |
Total enclosures |
301 |
9 |
“Control” device |
302 |
179 |
Attitude |
303 |
71 |
“Control” device |
||
Drag increase |
304 |
34 |
Other purpose |
305 |
42 |
Boundary layer control |
306 |
17 |
Wing-located |
307 |
104 |
T.E. region |
308 |
76 |
L.E. region |
309 |
21 |
Other |
310 |
11 |
Fin located |
311 |
26 |
Foreplane/Tailplane located |
312 |
34 |
Body located |
313 |
13 |
Other location |
314 |
5 |
Flap type |
315 |
93 |
Plain |
316 |
23 |
Split |
317 |
18 |
Other |
318 |
16 |
Spoilers/Vortex generators |
319 |
15 |
Fences/End plates/Flow guides |
320 |
17 |
Auxiliary aerofoils/Slats |
321 |
12 |
All moving component/ Tip |
322 |
16 |
Tabs/Balancing devices |
323 |
20 |
Parachute |
324 |
10 |
Thrust reversal/Jet deflection |
325 |
10 |
Other objects |
||
Engine |
326 |
74 |
Compressors/Turbines/ Windmills/Fans/Pumps |
327 |
42 |
Cascades/Stators |
328 |
5 |
Ground/Runways/Ground Facilities |
329 |
11 |
Catapults/Launching devices |
330 |
11 |
Ships/Watercraft |
331 |
6 |
Man/Medicine |
332 |
6 |
Flat Plate |
333 |
28 |
Cylinder—perpendicular to flow |
334 |
3 |
Particles/Droplets |
335 |
5 |
Other solid |
336 |
6 |
Geometry |
||
3-Dimensional |
337 |
274 |
Other |
338 |
73 |
Full scale |
339 |
173 |
a Times used in the indexing of 700 documents. |
|
Code No. |
Timesa used |
Other |
340 |
261 |
Rough surface/(Surface condition) |
341 |
17 |
Steps |
342 |
11 |
Projections |
343 |
21 |
Fairings/Junctions |
344 |
16 |
Distortions/Bumps/ Indentations |
345 |
13 |
Recesses/Gaps |
346 |
9 |
Perforated/Porous/ Slotted surface |
347 |
35 |
Variable shape |
348 |
12 |
Aerodynamic interest |
349 |
569 |
Lift |
350 |
193 |
Drag |
352 |
232 |
Thrust |
353 |
43 |
Moments/Stability/Control Moments |
354 |
184 |
Stability |
355 |
176 |
Control |
356 |
102 |
Lateral |
357 |
108 |
Longitudinal |
358 |
209 |
Directional |
359 |
88 |
Hinge |
360 |
30 |
Damping |
361 |
44 |
Pressure/Velocity distribution |
362 |
192 |
Loads/Loading |
363 |
83 |
Interference/Relative position |
364 |
89 |
Stalling/High incidence |
365 |
53 |
Sideforce/Sideslipping |
366 |
34 |
Spinning |
251 |
27 |
Landing/Take-off |
367 |
56 |
Level flight |
407 |
28 |
Diving/Descent/Gliding |
368 |
34 |
Climbing |
369 |
24 |
Turning |
370 |
21 |
Hovering/Flapping |
242 |
14 |
Separating/Jettisoning |
371 |
13 |
Buffeting |
372 |
15 |
Flutter/Oscillation |
373 |
48 |
Aeroelasticity |
374 |
23 |
Magnus effect |
375 |
0 |
“Area rule” |
376 |
10 |
Operation/Design |
377 |
92 |
Load/Capacity/Performance/Range/Speed |
378 |
79 |
Operation/Design |
||
Economics |
381 |
16 |
Reliability/Maintenance/ Safety/Accidents |
382 |
25 |
Civil operation |
383 |
17 |
Military operation/ Strategy/Tactics |
384 |
45 |
Ballistics interest |
385 |
20 |
Structures/Materials interest |
386 |
47 |
Mechanical interest |
387 |
35 |
Electronics/Radar/Radio |
388 |
24 |
Mathematics |
389 |
51 |
Principal test equipment/ Technique |
||
Described |
391 |
133 |
Wind tunnel |
392 |
261 |
Continuous/Fan drive |
393 |
45 |
Intermittent |
394 |
8 |
Shock tube |
395 |
4 |
Special purpose tunnel/Test rigs |
396 |
23 |
Spinning tunnel |
397 |
10 |
Water tunnel |
398 |
4 |
Ballistic range |
399 |
4 |
Analogy/Simulator |
400 |
4 |
Ditching tank |
401 |
2 |
Towing tank/Moving channel |
402 |
12 |
Models mounted on air-craft |
403 |
1 |
Tracks/Sleds |
404 |
1 |
Free flight—Piloted aircraft |
405 |
92 |
Free flight—Models/unpiloted |
406 |
41 |
Components |
408 |
24 |
Power/Flow production |
409 |
15 |
Other |
410 |
13 |
Auxiliary Apparatus/Technique |
411 |
58 |
Model Design/Construction |
412 |
49 |
Balances |
413 |
18 |
a Times used in the indexing of 700 documents. |
|
Code No. |
Timesa used |
Principal test Equipment/ Technique |
||
Scale Effect/ |
414 |
31 |
Corrections/ Calibration Telemetry |
415 |
8 |
Data Handling/ Methods/Computers |
416 |
10 |
Flow visualization |
252 |
51 |
Instruments |
417 |
59 |
Combustion |
418 |
17 |
Meteorology |
419 |
8 |
Optics |
290 |
4 |
Photography |
165 |
11 |
Total postings in indexing 700 documents |
|
20,270 |
a Times used in the indexing of 700 documents. |