propfan

[′präp‚fan]

(aerospace engineering)

An advanced turboprop with very thin, highly swept blades to reduce both compressibility losses and propeller noise during high-speed cruise.

propfan

An advanced propeller for use at high Mach numbers. It has six to twelve blades. The sweeping of the blade delays the critical Mach number (M_crit) and reduces the noise from the tips of the blades. The sweep also alters the phase of the noise generated by each radial section along the blade, causing a certain amount of interference. This results in noise reduction. A propfan can be used either as a pusher or a tractor.

References in periodicals archive

EasyJet plane solution and it is no secret that their plane proposal shares many of the characteristics of the US propfan efforts in the late eighties and early nineties.

Company Watch - EasyJet

This lower tip speed may permit the application of lightweight composite material and a spar/shell construction similar to the swept, counterrotating, variable-pitch blades used on the open rotor propfan engine.

The turbofan of tomorrow

Thus was invented the propfan, an "ultra-high" bypass engine that is a throwback in two ways.

Saving fuel in flight: projects conceived in the oil-poor 1970s now bear fruit

Green sky thinking - carbon credits and the propfan comeback?

Travel Health & Environment Watch

Designed for the new Propfan jet engine, this seal has a stainless steel housing

Hermetic sealing with epoxy

It first flew in 1994, but its advanced propfan propulsion system has proved difficult to develop.

Ever so needed Airlift: in recessions, defence acquisition budgets are tight and transport aircraft are not normally high on wish lists. today, several major air forces have an overarching need to expand their air transport capacity

There is an argument in favour of the Russian Air Force having both the IRTA and the much larger Tu-330 (or the Ukraine's propfan An-70), but for the time being that service may have to settle for one or the other.

Hercules and beyond

In combination with ducted propfans and a swept wing, this was thought to provide potential for speeds up to 740 km/hr.

Advances in rotorcraft

The sole direct competitor for the A400M is the 145-tonne Antonov An-70, which is powered by 10,350-kW Progress D-27 engines turning 14-blade contra-rotating propfans. It has 22% more power and is claimed to have a shorter take-off and faster cruise than the A400M.

Transport aircraft in times of change

Older physically thanthe A400M, having first flown in 1994, but arguably more advanced technologically, having propfans rather than turboprops, the Antonov An-70 is a long-running on-again, off-again saga that might (if launched earlier) have become one of the aerospace success stories of the Soviet Union.

Change of air: A massive logistic operation is now ramping up, as most elements of the 49-nation International Security Assistance Force (ISAF) are to be withdrawn from remote, landlocked Afghanistan by the end of 2014. The US Army alone is estimated to have $ 27 billion of hardware in the country, including 25,000 vehicles and 100,000 shipping containers

The An-70 is powered by four 10,300-kW Ivchenko-Progress D-27 engines (25% more powerful than the TP400), turning 14-blade (eight at front, six at rear) contra-rotating SV-27 propfans. Its cabin is somewhat larger than that of the A400M, and it has a ten-tonne margin in terms of maximum payload (47 tonnes).

New-tech military airlifters: new-generation turbine engines with substantially improved thermodynamic and propulsive efficiencies are making possible transport aircraft that combine relatively short airfield performance with economical (and comparatively high-speed) cruise

The A-42 could be a development of the 86-tonne A-40 of 1986, since the company website refers to a 96-tonne Be-42PE with Progress D-27A propfans replacing the A-40's Soloviev D-30KPV turbofans.

Below us the waves