Northrop HL-10

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HL-10
Type	Lifting body
Manufacturer	Northrop
Designed by	Langley Research Center
Maiden flight	22 December 1966
Retired	17 July 1970
Status	On display
Primary user	NASA
Number built	1

The Northrop HL-10 was one of five heavyweight lifting body designs flown at NASA's Flight Research Center (FRC--later Dryden Flight Research Center), Edwards, California, from July 1966 to November 1975 to study and validate the concept of safely maneuvering and landing a low lift-over-drag vehicle designed for reentry from space. It was a NASA design and was built to evaluate "inverted airfoil" lifting body and delta planform.

Contents 1 Development 2 Operational history 3 What Might Have Been: the HL-10 In Space 4 HL-10 flights 4.1 Aircraft serial number 5 Specifications (Northrop HL-10) 5.1 General characteristics 5.2 Performance 6 References 7 Related content 8 See also

[edit] Development

Northrop Corporation built the HL-10 and Northrop M2-F2, the first two of the fleet of "heavy" lifting bodies flown by the NASA Flight Research Center. The contract for construction of the HL-10 and the M2-F2 was $1.8 million. "HL" stands for horizontal landing, and "10" refers to the tenth design studied by engineers at NASA's Langley Research Center, Hampton, Virginia. Main gear was a modified T-38 system retracted manually^{[citation needed]}, and lowered by nitrogen pressure. Nose gear was modified T-39 unit, retracted manually and lowered with nitrogen pressure. Pilot Ejection System was a modified F-106 system. Silver zinc batteries provided electrical power for control system, flight instruments, radios, cockpit heat, and stability augmentation system. To assist in pre-landing flare, four throttleable hydrogen peroxide rockets provided up to 400 lbf (1.8 kN) of thrust.

[edit] Operational history

After delivery to NASA in January 1966, the HL-10 made its first flight on December 22, 1966, with research pilot Bruce Peterson in the cockpit. Although the XLR-11 rocket engine (same type used in the Bell X-1) was installed, the first 11 drops from the B-52 launch aircraft were unpowered glide flights to assess handling qualities, stability, and control. In the end, the HL-10 was judged to be the best handling of the three original heavy-weight lifting bodies (M2-F2/F3, HL-10, X-24A).

The HL-10 was flown 37 times during the lifting body research program and logged the highest altitude and fastest speed in the lifting body program. On February 18, 1970, Air Force test pilot Peter Hoag piloted the HL-10 to Mach 1.86 (1,228 mph). Nine days later, NASA pilot Bill Dana flew the vehicle to 90,030 feet, which became the highest altitude reached in the program.

During a typical lifting body flight, the B-52 -- with the research vehicle attached to the pylon mount on the right wing between the fuselage and inboard engine pod -- flew to a height of about 45,000 feet and a launch speed of about 450 mph.

Moments after being dropped, the XLR-11 was lit by the pilot. Speed and altitude increased until the engine was shut down by choice or fuel exhaustion, depending upon the individual mission profile. The lifting bodies normally carried enough fuel for about 100 seconds of powered flight and routinely reached altitudes of 50,000 to 80,000 feet and speeds above Mach 1.

Following engine shutdown, the pilot maneuvered the vehicle through a simulated return-from-space corridor into a pre-planned approach for a landing on one of the lakebed runways on Rogers Dry Lake at Edwards. A circular approach was used to lose altitude during the landing phase. On the final approach leg, the pilot increased his rate of descent to build up energy. At about 100 feet altitude, a "flare out" maneuver dropped air speed to about 200 mph for the landing.

Some new and different lessons were learned through the successful flight testing of the HL-10. These lessons, when combined with information from its sister ship, the M2-F2/F3, provided an excellent starting point for designers of future entry vehicles, including the Space Shuttle.

• HL-10 pilots
  • John A. Manke - 10 flights
  • William H. Dana - 9 flights
  • Jerauld R. Gentry - 9 flights
  • Peter C. Hoag - 8 flights
  • Bruce Peterson - 1 flight

• Most of text taken from NASA Dryden webpage.

• Additional text taken for this NASA Dryden HL-10 Fact Sheet.

[edit] What Might Have Been: the HL-10 In Space

According to the book, "Wingless Flight", by project engineer R. Dale Reed, if he had had his way, the HL-10 would have flown in space in the early to mid-1970s. Following the cancellation of the Apollo moon project, Reed realized that there would be substantial Apollo hardware leftover, including several flight-rated command modules and Saturn V rockets.

His plan was to heavily modify the HL-10 at the Flight Research Center with the addition of an ablative heatshield, reaction controls, and other additional subsystems needed for manned spaceflight. The now space-rated vehicle would have then flown on an Apollo-Saturn V launch vehicle stack in the same space originally used for the lunar module. Once in earth orbit, it was planned that a robotic extraction arm would remove the vehicle from the rocket's third stage and place it adjacent to the manned Apollo CSM spacecraft. One of the astronauts, who would be trained to fly the vehicle would then spacewalk from the Apollo and board the lifting body to perform a pre-reenty check on its systems.

It was planned that there would be two flights in this program. In the first, the lifting body pilot would return to the Apollo and send the HL-10 back to earth unmanned. If this flight was successful, on the next launch, he would then pilot the HL-10 back to earth for a planned landing at Edwards AFB.

Reportedly, Wernher von Braun thought it was a wonderful idea and offered to prepare two Saturn V's and Apollo Command Service Modules for the mission. Unfortunately, Flight Research Center director Paul Bickle said no, stating that this was beyond his expertise or area of interest.^[1]

[edit] HL-10 flights

Vehicle Flight #	Date	Pilot	Mach	Velocity -k/hr-	Altitude - m -	Duration	Comments
HL-10 #1	December 22, 1966	Peterson	0.693	735	13,716	00:03:07	First HL-10 Flight Unpowered glide
HL-10 #2	March 15, 1968	Gentry	0.609	684	13,716	00:04:03	Unpowered glide
HL-10 #3	April 3, 1968	Gentry	0.690	732	13,716	00:04:02	Unpowered glide
HL-10 #4	April 25, 1968	Gentry	0.697	739	13,716	00:04:18	Unpowered glide
HL-10 #5	May 3, 1968	Gentry	0.688	731	13,716	00:04:05	Unpowered glide
HL-10 #6	May 16, 1968	Gentry	0.678	719	13,716	00:04:25	Unpowered glide
HL-10 #7	May 28, 1968	Manke	0.657	698	13,716	00:04:05	Unpowered glide
HL-10 #8	June 11, 1968	Manke	0.635	697	13,716	00:04:06	Unpowered glide
HL-10 #9	June 21, 1968	Gentry	0.637	700	13,716	00:04:31	Unpowered glide
HL-10 #10	September 24, 1968	Gentry	0.682	723	13,716	00:04:05	Unpowered glide XLR-11 installed
HL-10 #11	October 3, 1968	Manke	0.714	758	13,716	00:04:03	Unpowered glide
HL-10 #12	October 23, 1968	Gentry	0.666	723	12,101	00:03:09	1st powered flight engine malfunction landed Rosamond
HL-10 #13	November 13, 1968	Manke	0.840	843	13,000	00:06:25	3 tries to light engine
HL-10 #14	December 9, 1968	Gentry	0.870	872	14,454	00:06:34	-
HL-10 #15	April 17, 1969	Manke	0.994	974	16,075	00:06:40	-
HL-10 #16	April 25, 1969	Dana	0.701	744	13,716	00:04:12	Unpowered glide
HL-10 #17	May 9, 1969	Manke	1.127	1,197	16,246	00:06:50	1st lifting body supersonic flight
HL-10 #18	May 20, 1969	Dana	0.904	959	14,966	00:06:54	-
HL-10 #19	May 28, 1969	Manke	1.236	1,312	18,959	00:06:38	-
HL-10 #20	June 6, 1969	Hoag	0.665	727	13,716	00:03:51	Unpowered glide
HL-10 #21	June 19, 1969	Manke	1.398	1,484	19,538	00:06:18	-
HL-10 #22	July 23, 1969	Dana	1.444	1,350	19,446	00:06:13	-
HL-10 #23	August 6, 1969	Manke	1.540	1,656	23,195	00:06:12	1st four chambered flight
HL-10 #24	September 3, 1969	Dana	1.446	1,542	23,762	00:06:54	-
HL-10 #25	September 18, 1969	Manke	1.256	1,341	24,137	00:07:06	-
HL-10 #26	September 30, 1969	Hoag	0.924	980	16,383	00:07:16	-
HL-10 #27	October 27, 1969	Dana	1.577	1,675	18,474	00:06:57	-
HL-10 #28	November 3, 1969	Hoag	1.396	1,482	19,544	00:07:19	-
HL-10 #29	November 17, 1969	Dana	1.594	1,693	19,687	00:06:48	-
HL-10 #30	November 21, 1969	Hoag	1.432	1,532	24,165	00:06:18	-
HL-10 #31	December 12, 1969	Dana	1.310	1,402	24,372	00:07:08	-
HL-10 #32	January 19, 1970	Hoag	1.310	1,399	26,414	00:06:50	-
HL-10 #33	January 26, 1970	Dana	1.351	1,444	26,726	00:06:51	-
HL-10 #34	February 18, 1970	Hoag	1.861	1,976	20,516	00:06:20	Fastest lifting body flight
HL-10 #35	February 27, 1970	Dana	1.314	1,400	27,524	00:06:56	Highest lifting body flight
HL-10 #36	June 11, 1970	Hoag	0.744	810	13,716	00:03:22	Lift/Drag powered approach
HL-10 #37	July 17, 1970	Hoag	0.733	803	13,716	00:04:12	Last flight

[edit] Aircraft serial number

• Northrop HL-10 - NASA 804, 37 flights

[edit] Specifications (Northrop HL-10)

[edit] General characteristics

• Crew: one pilot
• Length: 21 ft 2 in (6.45 m)
• Wingspan: 13 ft 7 in (4.15 m)
• Height: 9 ft 7 in (2.92 m)
• Wing area: 160 ft² (14.9 m²)
• Empty: 5,285 lb (2,397 kg)
• Loaded: 6,000 lb (2,721 kg)
• Maximum takeoff: 10,009 lb (4,540 kg) (propellant wt 3,536 lb - 1,604 kg)
• Powerplant: 1 x Reaction Motors XLR-11 four-chamber rocket engine. 8,000 lbf (35.7 kN) thrust

[edit] Performance

• Maximum speed: 1,228 mph (1,976 km/h)
• Range: 45 miles (72 km)
• Service ceiling: 90,303 ft (27,524 m)
• Rate of climb: ft/min ( m/min)
• Wing loading: 62.5 lb/ft² (304.7 kg/m²)
• Thrust-to-weight: 1:0.99

[edit] References

1. ^ Reed, R. Dale; Darlene Lister (2002). Wingless Flight: The Lifting Body Story. University Press of Kentucky. ISBN 0813190266.  also available as a PDF file.

• NASA Dryden HL-10 Photo Collection
• Developing and Flight Testing the HL-10 Lifting Body - NASA 1994 (PDF)

[edit] Related content

Related development:

Comparable aircraft: X-24 - M2-F1 - M2-F2 - M2-F3 - X-38 Crew Return Vehicle

Designation sequence:

[edit] See also

• X-plane - A list of all the X planes
• List of experimental aircraft
• HL-20 Personnel Launch System