BRITISH AND GERMAN AIR-POWER
[To the Editor of THE SPECTATOR]
Sta,—Referring to my recent article, "British and German Air-Power," Mr. Hugh Ledward asserts that I am misinformed regarding the inferior service given by the B.M.W. engines on the German Junkers 86K bomber. To prove his point he cites the outstanding service given by these engines when fitted to the Junkers 52 civil air-liner.
In the first place, I would like once more to state that my information came from a most reliable source. Additional confirmation came with the dismissal of the high officer who recommended the purchase of the machines to his Government.
But let us consider Mr. Ledward's apparently plausible argument. There are a number of possibilities which would explain the different behaviour of the engines. Let me state one of the most likely.
The reliability of an aircraft engine is dependent entirely on the amount of power that is normally taken out of it. If It is run at Tull power, or anything like full power, for periods of more than a few minutes, something will be weakened. A racing engine, for instance, has a much shorter life than an ordinary engine. The result is that, for reasons of reliability and economy, a pilot only uses a proportion of the power that is available. The Lockheed 14 has two engines of r,roo horse- power each, yet only 5o per cent, of this is used for normal flying. It follows, theiefore, that if the bombers in question were sold on high performance, their engines might have to be run at 8o per cent. of full power in order to attain that stated performance. This would account for a considerable difference in their reliability when fitted to the civil Junkers 52 and the military Junkers 86K.
But there is another point. The Junkers 52 has three engines for a loaded weight of 23,000 lbs. The Junkers 86K has only two engines for a loaded weight of rEi,000 lbs. In other words, each engine of the 52 has to pull through the air about 7,600 lbs., whereas each engine of the 86K has as much as 9,000 lbs., or half a ton more.
While not by any means stating that the above arc the actual reasons for the differing reliability of the two types of aircraft, I believe that they at any rate destroy the plausibility of Mr. Ledward's example and that they show that my information may be as reliable as I daim.—Yours very truly, 17 Half Moon Street, London, W. I.
NIGEL TANGYE.
Previous page
