JPALS landing aid for Coast Guard?

US Navy Photo. JPALS tactical prototype

The Navy has already chose Joint Precision Approach & Landing Systems (JPALS) and BreakingDefense reports Raytheon is offering it to the Air Force and Army. Perhaps the Coast Guard should take a look. Like the Navy, the Coast Guard operates aircraft from moving ships, with perhaps even more  “pitch, roll, surge, sway, heave, yaw, and translation”

JPALS fills the role of a TACAN, giving bearing and range to the landing area, but does it with much greater accuracy, directing the aircraft to a 20 cm (7.8″) square area, using differential GPS. It does it all in any weather and zero visibility with very low probability of intercept and in an encrypted format by data link, minimizing the need for radio communications.

Every time we turn on TACAN we broadcast the position of ship. 

Potentially it can provide a autonomous recovery for aircraft and UAVs.

“What’s more, Raytheon is finishing development of a capability for JPALS to take over the flight controls and bring the aircraft in for an automated landing with no input from the pilot – or potentially with no pilot on board at all. That is why the Navy has contracted with Raytheon to put JPALS on its future MQ-25 carrier-based drone.”

Maybe our over-the-horizon boats could use it too.

Innovation in Propellers

Tip vortices – conventional versus Kappel. Tip vortices are tubes of circulating water that are formed at the tip as the propeller generates thrust.

Tip vortices – conventional versus Kappel. Tip vortices are tubes of circulating
water that are formed at the tip as the propeller generates thrust.

gCapatain has photos of a new type of propeller.

Although I have a hard time seeing it in the photos, this shape is similar in concept to the upturned wing tips that now common on commercial aircraft. Propellers are after all, really just wings that rotate around a central hub. Having seen this, I now wonder why we haven’t seen this before.

Diagrams of fluid flow over a airfloil section usually show a linear flow from the leading edge to the trailing edge, but actually there is also a span-wise flow that spills off the tips and creates vortices. They add drag and increase noise.

Photo: The air flow from the wing of this crop duster is made visible by a technique that uses colored smoke rising from the ground

Of course the reason the airlines use these devices is to improve fuel economy. The principle also works for propellers.