30 June 1961 - The Black Vault

I
j
'I
123
eq1Jlpped with dual XLR-ll eng1neB~
but cancelled to a captive
flight four mtnutes prior to launch when an X..15aux1liary ,power
UIlit failed. McKay w~sre. acheduled on 1 February and made an
uneven·tfulpowered fllght, Major Rohellt tlf, Whlte. USAF J
using
thesameX-15 On 7 February pushedtne.ll engines to a
maxim\llll speed of ·2 .. 275 ul11es' ,per hour. This was the fastes tspeed
everachievedwlth ~.X~15 powere~ byd:ual~';;'ll ehginesand
was acc.omp11S~47dwh1Iesimulat1ng a flight pattern to be used
later w1th the X.. l~r : eQ.ulpped wtth the largerxtR...99 e.ng1.ne.
Following thefllght by MaJorWh1te on7 February, X-lS USAF
SiN 56~6670 was returned· to North A:merlcanAviatlon for modification
andj,nstallaticm of the XLR-99 engine. 8
Rev1ewor X-15FlightsWlth DUal XLR .. l1~£nes
Major 'Wh.lte l ·s flight .on 1 February 1961 completed the flight
program for X-15'sequj.pped wlthdual XLR-ll 'engines. Accompl:1shmen,ts
in the two ye~:r span since the first captive .flight on 10
Marc"'! 1959 were too numerous to detail herein 9 However, areas in
which major ac·hievements and investigations of the X-15 made
1nit1ally included aerodynamic and systems checks. compatabiI1ty
of the B-52 carrier aircraft and the X-IS. f"u.nc t10nal checks of
subay~tem6
to 45,000 feet alt1tude, and systems and subsystems
operational checks at various altitudes to 38,000 feet.
8, i'I1stof Flight Teat Efi.gin_eer1ng Div., Dlr.ec torate of
Flight 1'e~t, APFV:rC, Fob 19b1 ­
9. See Appendix B ,and semiannual 1'"t18to:ries of the AFF'fC s1nce
January 1959 for details of each flight.
5 - 4
,