This video shows the movement of the top of Velocity aircraft N2XF's nose gear leg during taxi, takeoff and landing operations. In the Velocity, the top of the nose gear leg connects to a shock absorber, which in turn is connected to the gear leg hydraulic actuation and over-center linkage. The nose gear leg pivots on a 1/2" bolt so that the nose tire (attached to the bottom of the nose gear leg) can rotate out of the windstream and into the nose compartment when the aircraft is airborne.
Fore and aft movement of the nose gear leg occurs normally while the aircraft is on the ground as bumps and dips in the pavement cause the shock absorber to compress in response. Side-to-side movement of the nose gear leg is undesirable and is prevented by a U-shaped bracket called the 'Captivator'. The captivator is hard mounted to the nose bulkhead in the aircraft and serves as a visual reference for the amount of movement of the top of the nose gear leg in the video. In the video the captivator bracket is painted green and the top of the gear leg is white. If the top of the nose gear leg should move completely aft of the bracket, the captivator would no longer be able to prevent side-to-side motion of the nose gear leg and linkage.
One of the more interesting and surprising sections of the video shows how much the top of the nose gear leg moves aft at the start of the take-off roll when full power is applied but with the brakes fully engaged to prevent forward movement of the aircraft (so the pilot can verify proper engine operation prior to committing to the take-off roll). The captivator bracket material is approximately 1/8 of an inch thick, so it can be seen that the top of the gear leg moves about 1/2 inch aft and that only the last 3/8 inch of the captivator continues to retain the gear leg. The degree of movement shows how much the nose of the aircraft is 'compressed' by the full power of the engine. In comparison, the movement of the top of the gear leg during aircraft rotation for take-off and the shock of nose gear touchdown during aircraft landings is relatively small. Significant movement also occurs during taxi, take-off roll, and landing roll-out operations.
Compared to a typical Velocity XL-RG aircraft, N2XF has about twice the nose wheel weight. However, the pre-load of the nose gear linkage shock absorber has also been increased substantially to compensate. The video appears to show that an appropriate balance between nose weight and shock absorber strength has been achieved.
The video was captured using a 'VideoStik' borescope, threaded through an inspection hole drilled into the side of the keel. The video stick uses internal LEDs for lighting and provides an analog video output that was connected through a digitizer to a laptop in order to record the video to a hard disk drive in real time during the flight. Another N2XF video may be found at [ Ссылка ] .
