NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Laboratory Investigation of Ice Formation and Elimination in the Induction System of a Large Twin-engine Cargo AircraftThe icing characteristics, the de-icing rate with hot air, and the effect of impact ice on fuel metering and mixture distribution have been determined in a laboratory investigation of that part of the engine induction system consisting of a three-barrel injection-type carburetor and a supercharger housing with spinner-type fuel injection from an 18-cylinder radial engine used on a large twin-engine cargo airplane. The induction system remained ice-free at carburetor-air temperatures above 36 F regardless of the moisture content of the air. Between carburetor-air temperatures of 32 F and 36 F with humidity ratios in excess of saturation, serious throttling ice formed in the carburetor because of expansion cooling of the air; at carburetor-air temperatures below 32 F with humidity ratios in excess of saturation, serious impact-ice formations occurred, Spinner-type fuel injection at the entrance to the supercharger and heating of the supercharger-inlet elbow and the guide vanes by the warn oil in the rear engine housing are design features that proved effective in eliminating fuel-evaporation icing and minimized the formation of throttling ice below the carburetor. Air-flow recovery time with fixed throttle was rapidly reduced as the inlet -air wet -bulb temperature was increased to 55 F; further temperature increase produced negligible improvement in recovery time. Larger ice formations and lower icing temperatures increased the time required to restore proper air flow at a given wet-bulb temperature. Impact-ice formations on the entrance screen and the top of the carburetor reduced the over-all fuel-air ratio and increased the spread between the over-all ratio and the fuel-air ratio of the individual cylinders. The normal spread of fuel-air ratio was increased from 0.020 to 0.028 when the left quarter of the entrance screen was blocked in a manner simulating the blocking resulting from ice formations released from upstream duct walls during hot-air de-icing.
Document ID
19930082173
Acquisition Source
Glenn Research Center
Document Type
Other - NACA Technical Note
Authors
Colis, William D
(National Advisory Committee for Aeronautics. Aircraft Engine Research Lab. Cleveland, OH, United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1947
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
NACA-TN-1427
Report Number: NACA-TN-1427
Accession Number
93R11463
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
ICE PREVENTION - AIR HEATING
ICE PREVENTION - INDUCTION SYSTEMS
AIRPLANES, CARGO
ICE PREVENTION - SUPERCHARGER INLET ELBOWS
FUEL-AIR MIXTURES
ICE PREVENTION - CARBURETORS
ICE FORMATION
No Preview Available