Page 11 - The Future of Aerospace is X - X-Planes 2021

X-5 Research Aircraft

The Bell X-5 was built to test the feasibil- proved the project on February 4, 1949. A composite
ity of changing the sweep angle of an aircraft’s A pair of X-5s were built, serial numbers 50- photograph
wings in flight. This had advantages from both 1838 and 50-1839. They were similar in shape to showing the Bell
an operational and research point of view. the P.1101 design, with a nose-mounted intake, X-5’s variable-
An operational aircraft could take off with a bubble canopy, an underslung engine, and a sweep wing.
its wings fully extended, reducing both its take boom-mounted tail. The wings pivoted from a
off speed and the length of the runway needed. 20 to 60 degree angle in flight. The mechanism
Once in the air, the wings could be swept used to swivel the wings was very complex. As
back, reducing drag and increasing the air- the X-5’s wings were swept back, its center of
craft’s speed. For an experimental aircraft, the gravity and center of pressure changed. To com-
ability to vary the wing’s sweep angle would pensate, the entire wing assembly simultaneous-
greatly expand the research possibilities. Exist- ly moved forward on rails inside the fuselage.
ing swept wing experimental aircraft, such as Sweeping the wings from a 20 degree angle to
the D-558-II, XF-92A, X-2 and X-4, could each the full 60 degree angle required that they also
provide aeronautical data at only a single wing be moved about 27 inches forward from their
angle. A variable swept wing aircraft would be starting position. The change from 20 to 60 de-
equivalent to a series of such experimental air- grees required about 20 seconds. In the event of
craft, as it could change the wing angle to the an electrical failure, the pilot could hand crank
desired research objectives. the wings back into landing position. (The X-5
Although NACA conducted independent could not safely land with a sweep angle greater
wind tunnel research on variable sweep wings than 40 degrees.)
in 1945, the X-5 originated with the Messer- The first X-5 (50-1838) was delivered to Ed- Courtesy photograph
schmitt P.1101 experimental aircraft. This was wards Air Force Base, Calif., on June 9, 1951.
a small jet with wings that could be adjusted on It made its first flight 11 days later, on June 20. NACA research pilot Joe Walker was assigned pilot through mid-1954.
the ground to three fixed angles between 35 and Bell company test pilot Jean “Skip” Ziegler to the X-5 program. He made a pilot checkout The X-5 research program, in contrast to that
45 degrees. The P.1101 had not flown before it made the initial Phase I flights, to prove the air- flight on Jan. 9, 1952, the day after the first X-5 of the X-3 and XF-92A, was quite extensive. Al-
was captured by U.S. troops in April 1945. The plane’s airworthiness. On the X-5’s ninth flight, was transferred to NACA. The initial research though the focus remained on stability and con-
aircraft was examined by Bell Aircraft engineers made on July 27, Ziegler tested the wing sweep flights involved static and dynamic longitudi- trol, other areas of research included vertical tail
following its arrival in the United States. Robert mechanism for the first time. The Phase I flight nal and lateral stability and control. Walker also loads in maneuvers, gust loads at various sweep
Wood, head of Bell’s design team, proposed in continued through July and August 1951, with tested the X-5’s stability and control with the angles, wing twisting and bending tail loads, the
July 1948 that a modified and enlarged version the 20th and final Phase I flight made on Oct. wings swept back 45 and 60 degrees, as well effects on trim from shifting the wings, the re-
of the P.1101 be built. Unlike the original air- 8, 1951. Maj. Frank Everest made six Air Force as its response to gusts with the wings in the 20 sponse of strain gages to temperature, and the
craft, the proposed Bell aircraft could change its flights in the aircraft during December 1951 and and 60 degree position. In April 1952, two more effects of dynamic pressure on buffeting. The
sweep angle in flight, rather than being set on January 1952. After a final flight by Everest on NACA pilots joined the X-5 program, A. Scott ability to set the desired sweep angle was also
the ground before takeoff. NACA, which had Jan. 8, 1952, the first X-5 was turned over to Crossfield and Walter P. Jones. Jones made eight used. A flight by Walker on February 10, 1954,
continued to make studies of variable sweep NACA. The second X-5 (50-1839) had, by this flights in the X-5 before leaving NACA, while for instance, collected lateral and longitudinal
aircraft, supported Bell’s proposal. This was a time, also been delivered and was flown by the Crossfield flew a total of 10 missions from 1952
major reason why Air Force Headquarters ap- Air Force. through 1954. Walker remained the primary X-5 See X-5, Page 12

HONORING OUR
®
HEROES

As a "Thank You" to those who have or are
currently serving in the military, or as a firefighter,
police officer, or a teacher we'd like to give you a
special discount on a brand new home!

Apply 1% of the base price of a new home from
Woodside Homes Arizona toward the home
options of your choice.

Choose from hundreds of upgrades and create
your own wonderful place to call home because
_
you've done the same for us.

FOR MORE INFORMATION CONTACT OUR ONLINE SALES PROFESSIONALS BELOW
Terry Barson Sara Fritz

MyNewHome-Arizona@woodsidehomes.com
623-469-0153

In an effort to continually improve our plans and designs, Woodside Homes reserves the right to make modifications in materials, plans and specifications without prior notice. Prices are subject to
change without notice. This advertisement is for illustration purposes only and not part of a legal contract. Models do not reflect racial or other demographic preferences. Eligibility: The program
provides a credit towards home options in the amount of 1% of the base price of the new home. This discount program is available for active and retired military, and currently full-time employed
firefighters, police officers, and teachers with current teaching certificates/degrees. Confirmation of service/employment required. The home must be used for a personal residence. The program is
valid for sales contracts signed from 1/1/2021 to 12/31/2021. The program may be discontinued at any time without notice. If you are working with a REALTOR, they must accompany and register WoodsideHomes.com/Arizona
you on your first visit. See sales professional for full details. 01/2021

Aerotech News and Review
July 16, 2021 www.aerotechnews.com ........ facebook.com/aerotechnewsandreview 11