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Aviation History
1969
1969 - 1686.PDF
439 FLIGHT/nternot/ona/, 20 March 1949 F-111/Phantom Cost-effectiveness SIR,—Current monetary values are confusing enough, especially the $/£ relationship. The figures given by the Minister of Defence for Equipment (as reported on page 309 of Flight for February 20) are even more confusing. As by the same token we are forced to shop around these days to make ends meet, it is opportune to make a simple calculation of the comparative cost-effectiveness to us of buying Phantoms and/or P-llls in terms of "lb of bombs per £ sterling" for our defence needs. Assuming that the annual rate of flying is 300hr per aircraft, that the consumption of spares, fuel, engines, etc, is geared to this rate, and that the capital cost of the initial provision of spares, engines, ground equip ment and facilities (such as concrete—30 per cent less for taking-off and landing the F-lll, credited to the swing wings) is equal to the capital cost (at fly-away prices) of the aircraft, my figures come out something like the following. The £ is assumed to be worth $2.4. at current values, for the whole ten-year life of the aircraft. Aircraft (Mk 1)* Phantom F-lll Fly-away cost (l»6B price) £2.l8m £2.56m Ground support £2.18m £2.56m DOC (inc s.f.c.) £0.64 m £0.B8m Total (one off) £5tn £6m Bomb load l-V 3.V •Comparative weights and operating ranges are self-cancelling. Comparative cost-effectiveness:— Phantom, £5m per IX lb bomb load. F-ll I. £2m per IX lb bomb load. Thus it would appear that the F-ll t is two-and-a-half times better value than the Phantom. In actual operational practice in Vietnam it has been proved that the relative costs of air support are even more significant in that the F-lll is self-supporting in regard to the provision of air cover, reconnaissance, air-fuelling, ECM and RCM aircraft. Therefore, as a complete weapon system, the F-lll appears to be incomparable. Windlesham. E. A. HARROP. Surrey Gp Capt Ret) Tripping over the Threshold SIR,—As a Vulcan Mk 2 pilot I read with interest "Mainliner's" article (February 27) "Those Dangling Wheels." He said how he wouldn't like to break out at 300ft in a 747 to achieve a 35ft wheel clearance using 3° glideslope. The Vulcan, with its high nose attitude and speed instability problems, is a difficult aircraft to handle on the approach. The wheel clearance using 3° glideslope is 25ft. How would "Mainliner" like to break out below 300ft in a Vulcan using a 3° glideslope? I am not au fait with the settings of the VASls used at civil airfields, but the settings we use give indications as follows: — Upwind VAS1 Rear VASI 3-T PINK WHITE 3° RED WHITE 2i° RED PINK Therefore, it is possible to be scraping in at the bottom end of the red/white sector on a glideslope of just slightly above 2V, wheTe the wheel clearance is cut down considerably. I think "Mainliner" ia wrong in saying "it will not be of use to pilots or operators merely to issue warnings of the dire dangers in undershooting." After all, this is all we have. Or could it be that he is implying that civil pilots haven't the ability to cope with the situation? Incidentally, we often have occasion to use fighter air fields with a 2£° glideslope and touchdown point 500ft in from the threshold, giving us a wheel clearance of minus 5ft over the threshold if we adhere to the VASI indications all the way down. Scampton, Lines J. BROWN Unfair to "Bucket and Spade" Traffic? SIR,—With reference to the leading article in Flight for February 27, I feel that you have been unfair to the "bucket and spade traffic to Majorca." This "bucket and spade" traffic had been responsible for quite a large growth of Britain's civil aviation. And, surely, the profit made by these independents on "bucket and spade" services helps to finance the internal scheduled services in the British Isles for the "industry and export" men. Also, the fact cannot be ignored that, seeing so many British tourists using British airlines, a foreign country in the market for aircraft cannot but be impressed; and this goes to help the "industry and export" men to sell British aircraft in foreign countries. Colomiers, France M. c. HARRISON Aft e.g. Czechs SIR,—Reading Sir George Edwards's lecture (Flight. February 6 and 13) brings to mind an occasion last year, when we had a Czechoslovakian student, working for Czechoslovak State Airlines, residing in the YMCA at Reading. He said that CSA wanted to purchase the VC10 but, because of the cost of extra tooling for maintenance to cope with different dimensions used in British manufac ture, an eventual decision in favour of the 11-62 was made. He also mentioned that, whilst Czech VIPs were being entertained aboard the 11-62 one day, so many went to the bar at the rear that the e.g. was changed to such an extent that the aircraft tipped on to its rear fuselage. A sure sign that Western decadence prevails in the East European aeronautical industry. Cambridge R. M. KILLICK. Adjustable-datum Horizons SIR,—Readers who have seen references in your columns to the issue of Aeronautical Information Circular No 14/1969 may be interested in the following extracts from a letter addressed by the undersigned to the Board of Trade's Aeronautical Information Service (AIS 1): — "I refer to the above circular relating to light fixed- wing aircraft equipped with an adjustable artificial horizon reference. "The case against such an adjustable reference is valid and well reasoned. No mention is made, however, of the case for such adjustable instruments, although such a case does exist and is considered by many to be at least equally valid. "The American light aircraft industry dominates world markets and to a large extent sets the standards, which are accepted world-wide. Commercial considerations sometimes seem to outweigh those of safety in dictating detail design which is cheaper, lighter and perhaps less safe than is desirable. "In the case of Circular 14/69, however, the situation is quite different. For reasons of their own the Americans are fitting an instrument which is appreciably more expensive to produce and fractionally heavier than the equivalent desired by our Air Registration Board. Surely it behoves us to examine the reasons before we go to the length of issuing a circular on the subject. "It is a fact of life that modern light aircraft have, in their normal cruise operation, a greater range of indicated airspeed than have heavy transport aircraft.
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