Hybrid airship
A dynastat is a hybrid airship with fixed wings and/or a lifting body and is typically intended for long-endurance flights.
A rotastat is a hybrid airship with rotary wings and is typically intended for heavy lift applications.
By combining dynamic and buoyant lift, hybrids are intended to provide improved airspeed, air-cargo payload capacity and (in some types) hovering capability compared to a pure airship, while having longer endurance and greater lifting capacity compared to a pure aerodyne.
This perception of uncommon dynamic flight range when coupled with an appropriate landing system is claimed to allow ultra heavy and affordable airlift transportation.
[2] Where the dynastat is seen as more promising in the longer-distance passenger and freight roles, the rotastat is anticipated to be more suitable as a "flying crane" able to lift heavy external loads for shorter distances.
Configurations studied have included using deltoid (triangular), lenticular (circular), or flattened hulls, or adding a fixed wing.
Some early airships were fitted with wing planes, with the intention of providing additional dynamic lift.
[citation needed] However, the added lift of planes can be less efficient than simply increasing the volume of the airship.
[4] Moreover, the attachment of flying surfaces to the airship's envelope would require significant structural strengthening, with attendant weight gain.
[2] Another issue arises during takeoff and landing, when, in calmer conditions, the airspeed may be too low to provide sufficient aerodynamic lift.
[6] For this reason, the dynastat is often conceived of as a STOL rather than VTOL aircraft, requiring a shorter runway than a conventional airplane.
[2] In more recent times, the experimental Piasecki PA-97 "Helistat" attached four helicopter airframes to a helium blimp, while the SkyHook JHL-40 remains a project.
In this way, an airship which periodically alternates its buoyancy between positive and negative, while adjusting its attitude accordingly, can gain almost continuous aerodynamic forward thrust.
Because no energy is consumed directly in creating thrust, the principle allows for flights of long duration, although at slow speeds.
Historically, this principle of aerial navigation, under the name of Wellenflug (wavy flight) was first formulated and experimentally tested in the year 1899 by Konstantin Danilevsky [ru] in Kharkov, Russian Empire, and described in detail in his book/[8] Gliding under gravity dates from the period during and shortly after the American Civil War, when Solomon Andrews built two such airships.
[citation needed] The 1986 Piasecki PA-97 Helistat experimental design combined four helicopters with a blimp in an attempt to create a heavy-lift vehicle for forestry work.
It was an unsuccessful candidate for the military Long Endurance Multi-intelligence Vehicle program even though it was the only successful Hybrid Airship to have ever flown until 7 August 2016.
Chief Test Pilot Dave Burns said in a statement "It was privilege to fly the Airlander for the first time and it flew wonderfully.
Airlander 10 completed design certification testing before being written off[22] when it came loose from its moorings in a high wind on 18 November 2017 at Cardington Airfield.
The idea is to create a viable platform that can travel anywhere in the world delivering cold medical supplies and other necessitates to locations in Africa and Northern Canada without needing any kind of fuel or infrastructure.
[7] Hunt suggest that the low power consumption should allow the craft to harvest sufficient energy to stay aloft indefinitely.
