ground resonance

Suffered badly from ground resonance and eventually shook itself apart.

The C.29 suffered from ground resonance during ground running and was not flown.

The Brantly 305 suffered from a ground resonance problems.

Vibration in the framework then coupled with a helicopter phenomenon known as ground resonance.

Also, they were susceptible to ground resonance.

Aérospatiale engineers hoped to reduce vibration and ground resonance.

Video of a CH-47 Chinook being forced into ground resonance and self destructing.

However, the danger of Ground resonance may require dampers so touchdown shocks or jolts are not transmitted to the main rotor system.

Video of a Brazilian rescue AS350BA breaking apart after landing due to ground resonance.

Despite appearances the oleos act in tension, not compression, damping the reflex action to prevent the aircraft bouncing and ground resonance when landing.

This allowed Saunders-Roe to finally demonstrate that the ground resonance problems had been fixed with the Skeeter Mark 5 in March 1954.

Ground resonance is a hazardous condition that can occur any time the rotor of a helicopter or autogyro is turning while the aircraft is on the ground.

The XR-2 was destroyed by rotor ground resonance problems and the evaluation was continued with another modified YG-1B designated the XR-3.

Art reviewer Enrico Gomez spoke to AHN's "grounding resonance" saying, "It optically strums like an electric bass and has considerable gravitational pull. "

A prototype MBB BO 105 also used a Scout main rotor head and blades during the development phase, unfortunately this aircraft was destroyed due to ground resonance during its initial trials.

Ground resonance is precipitated by a shock to the aircraft arising from excessive motion of a rotor blade in its plane of rotation thereby moving the rotor center of gravity from the axis of rotation.

The first Type 173 Mk 1 registered G-ALBN made its first hovering flight on 3 January 1952 but it only liked flying backwards, after landing from a second hovering flight ground resonance developed.

The C.8R incorporated drag hinges, due to blade flapping motion causing high blade root stresses in the rotor plane of rotation; this modification, however, resulted in other problems such as ground resonance for which drag hinge dampers were fitted.

The Skeeter 2 first flew on 15 November 1949, but it soon became apparent that it suffered from severe ground resonance problems that Cierva struggled to resolve, causing it to be destroyed during ground testing on 26 June 1950.

Ground resonance occurs at three rotor RPM bands, the first at about one-third of normal rotor speed, the second at a range including normal rotor speed, and the last in a range above normal rotor speed.

Testing showed that these aircraft remained underpowered and that the ground resonance problems had not been resolved, causing official interest to be suspended with Saunders-Roe undertaking a long series of company funded tested to identify the causes and to identify solutions to the problems.

Similar in concept to the behavior of a washing machine when the clothes are concentrated at one point during the spin cycle, ground resonance can occur with a rotorcraft when the spacing between blades becomes irregular or the damping system, including drag hinge dampers, landing gear oleo struts, or wheel tire pressure, is operating out of limits.