HYPERPLANE

Ranjith RajeevS7 M.E.Roll no. : 38

What is a hyperplane ? For a vehicle to be considered

hypersonic, it must travel at least at Mach 5 -- five times the speed of sound, or about 3,800 mph.

Hyperplane is an aircraft which travels at a speed greater than mach 5.(Commercial aircrafts fly at a speed of mach 0.8).

It can be used as space launch vehicles, military aircrafts and commercial aircrafts.

Design considerations :

‘Streamlined body’ is the criterion for design of a subsonic vehicle while ‘reduction of wave drag’ is the criterion for design of a supersonic vehicle

Excessive heating is the greatest concern in design of hypersonic vehicles.(The nose of the reentry vehicles attain a temperature of 11000k.)

Stagnation point aerodynamic heating varies inversely to the square root of the nose radius.

Cooling methods : Cooling methods are mainly classified

into two categories : 1) Active and 2) Passive cooling.

Convective and Ablative cooling are the most effectively used cooling systems and they re classified as active cooling techniques.

The convective cooling technique uses a coolant which absorbs heat from the surface to be cooled.

Convective cooling….

Cooling method continued…

In ‘ablation’ type active cooling, a layer of ablative material is coated over the surface to be protected. The protective layer melts and vaporizes due to heat load absorbing large amount of thermal energy.

Graphite and phenolic materials are currently popular ones for ablative materials. It is also found that the vehicle can be cooled efficiently by transferring coolant mass in the boundary layer from its surface.

Drag reduction : Bluntness at the nose of the hypersonic

vehicle is necessary to alleviate the oncoming heat load but at the same time this increases the drag.

Increase in drag results in more fuel requirement.

It is observed that a marginal reduction in drag increases the fuel efficiency greatly.

Aero spike based drag reduction: The spike recasts the original bow shock into a

conical shock and induces a low pressure recirculation region, which together forms an aerodynamic configuration similar to that of a slender body ahead of blunt body.

The consequence of separation is the formation of a low pressure and low temperature recirculation region or separation bubble near the stagnation region which reduces the drag.

Separated flow reattaches at the blunt body and the location of this reattachment point depends on the spike length, spike configuration and freestream conditions.

Aerospike based drag reduction..

Counter flow drag reduction :

Injection of a supersonic jet from the stagnation point of a blunt body changes the pressure and temperature distribution over the configuration of interest.

If the pressure of the jet is much higher than that of the free stream pressure then the jet separates at the edge of the orifice and moves forward.

Separation of the jet at the edge forms a toroidal recirculation region near the stagnation point. Expansion of the jet from the orifice continues until it passes through a terminal shock.

Counterflow drag reduction…

Avatar (Aerobic Vehicle for transatmospheric hypersonic Aerospace TrAnspoRtation)

Avatar structure…

Avatar working… It will take off from a usual runway using

air breathing engine and will reach sonic speed.

At sonic speed the ramjets get activated, bringing it to a hypersonic speed. During this travel it will suck air and seperate oxygen from that and will store it in liquid form.

Then it will use this fuel and liquid oxygen mixture for outer space propulsion.

Hypersoar

Hypersoar details… A 25-meter-long HyperSoar aircraft (about

as long as the wingspan of a large business jet) could make a conventional takeoff from a standard runway.

Using special air-breathing, rocket-based, combined-cycle engines, it would ascend to 40 kilometers-at the outer limit of Earth's atmosphere. 

 As it descends into denser air, the aircraft would be pushed up by the increased aerodynamic lift. 

Hypersoar details… The engines would fire briefly, propelling

the plane back into space. Outside the atmosphere, the engines shut off and the process repeats.

 In this way, HyperSoar would skip off the top layer of the atmosphere every two or so minutes, like a flat rock skittering in slow motion across the surface of a pond.

This is a very fascinating concept developed by Preston Carter.

Hypersoar working…

Hypersoar flight path…

THANK YOU..