Description
The following is a summary of the comments made by the staff of the NACA Ames Laboratory on the CF105 design:
(a) The subsonic drag estimate is probably correct.
(b) The supersonic drag estimate is optimistic. Ames considered that the supersonic CD??? would be between .025 and .030 instead of the .016 as estimated by AV Roe.
(c) The CD??? of 0.20 may be achieved for aircraft similar to the CF105 but will represent somewhat of an optimum figure for this class of aircraft.
(d) The area rule will over estimate the drag of the CF105 because of the low fineness ratio and large bumps
(e) The CF-105 should be modified at intakes and jetpipes to reduce the slope of the area distribution to reduce wave drag.
(f) Conical distribution positive camber will reduce the drag due to lift below the speed of sound but will increase it supersonically.
(g) There is some evidence that conical distribution positive camber may delay the pitch up tendency to a higher angle of attack.
(h) The leading edge notch and extended leading edge as advocated by AV Roe to prevent pitch up may cause a supersonic drag increment of 0.001.
(i) A continuous increase in wing leading edge radius from root to tip may do the same job as the notch and leading edge extension without the increase in drag.
(j) The use of suction to prevent separation of the boundary layer by the normal shock ahead of the intake has been successfully tried by Ames. Design data may be obtained from recent tests carried out by NACA Lewis Laboratory, Cleveland.
(k) The intake lips should be modified to be sharp on the outside and elleptical on the inside to reduce supersonic drag.
(l) The internal intake ducting should be of constant cross sectional area for a distance of two duct diameters before being gradually diverged to allow any separated boundary layer to re-attach.
