"Long Range Cruising Analysis and Control (First Edition)" [by Frank B. Lary, Wright Aeronautical Corporation], 1944-08

Document Type: Report (Technical).

Purpose: Technical Reference.

Authority: Author's Expertise and Company (Manufacturer).

Scope: Paper discusses improvements in both procedure and equipment as related to the cruise phase of flight.

Content:

From page 1: "In aviation's rather dim past, engine operators ordinarily fell in one of two classes, high rpm men and low rpm men, the latter being the least popular. The way in which a pilot operated the engines depended largely upon his personal preferences rather than upon consideration for the economy of the airplane and engine. This is undoubtedly reasonable for ships being operated over short distances with light pay loads. However, like everything else in the industry, size, weight, and pay loads of airplanes rose to staggering figures. Likewise, of necessity, the art of power control advanced to such an extent that maximum, even extreme, economy of the airplane-engine-propeller combination is now obtainable. Even though the data for accomplishing effective power control is available, the methods by which this data is selected are still shrouded in mystery to all but a few. These obscuring shrouds are entirely unnecessary because the processes used in establishing the operating conditions are basically simple. By definition, long range cruising is obtaining the maximum ground miles per gallon of fuel. It is simply necessary to assure that the airplane features are such that maximum miles per gallon are obtainable. It is only required that the characteristics of the three elements of the ship (wing, propeller, and engine) be analyzed to find conditions for maximum miles per gallon; and to present the conditions in such a way that the operator may use effective control. In all steps, miles per gallon is the keynote.

In the first place, the manufacturers of each element must make thorough studies of the other's product to insure that the resulting combinations may operate at best efficiencies of each part. The power requirements of the airplane for airspeeds producing maximum lift-drag ratio must be within economical power range of the engine. A combination of reduction gear ratio and propeller must be established so that the engine may approach the economical limits of combustion while the propeller produces the maximum thrust. Also, adequate engine cooling must be provided at the lean mixtures to be used. These selections must be compromised, to some extent, by considerations of take-off and climb performance."