초록 ▼

A model airplane for testing inside a wind tunnel has a fuselage and is mounted on a sting. A balance or force transducer is mounted on a forward end of the sting inside the fuselage of the model airplane and is of the strain gauge type for measuring forces acting on the model airplane. A plenum cha

A model airplane for testing inside a wind tunnel has a fuselage and is mounted on a sting. A balance or force transducer is mounted on a forward end of the sting inside the fuselage of the model airplane and is of the strain gauge type for measuring forces acting on the model airplane. A plenum chamber for receiving air is mounted forwardly of the balance inside of the fuselage of the model airplane. At least one air feed line extends from the sting to the plenum chamber and bypasses or bridges over the balance. An external air source feeds air from the sting through the air feed line to the plenum chamber. Inside the plenum chamber, there is an externally pressurized bellow assembly having an internal cavity at a pressure equal to the static pressure existing in the fuselage of the model airplane. A fitting at the end of the bellow assembly allows air to enter the plenum chamber so that such below assembly is externally pressurized. Thus, by this arrangement, negligible force interactions from the air flowing in the sting, the air feed line, and the plenum chamber are transferred to the balance for measuring forces acting on the model airplane. To aid further in avoiding force interactions on the balance, a flexured bellow element is arranged in each air feed line so that undesirable torsion, pitch, and other forces are absorbed thereby and are prevented from being transferred to the balance.

대표청구항 ▼

A model airplane having a fuselage for testing inside a wind tunnel, comprising: a sting; an air source, connected to the sting, for feeding air through the sting; a balance for measuring forces acting on the model airplane, said balance being mounted on the sting; a plenum chamber for receiving air

A model airplane having a fuselage for testing inside a wind tunnel, comprising: a sting; an air source, connected to the sting, for feeding air through the sting; a balance for measuring forces acting on the model airplane, said balance being mounted on the sting; a plenum chamber for receiving air therein, said plenum chamber being mounted inside the fuselage in communication with the balance; and at least one air feed line extending from the sting to the plenum chamber and bypassing the balance; whereby negligible force interactions from air flowing in the sting, the at least one air feed line, and the plenum chamber are transferred to the balance for measuring forces.