Andrew Doyle/MUNICH
Turboprop International (TPI) has switched to a three-shaft design for its M138 powerplant proposal for the Airbus Military Company (AMC) A400M and has formally presented an offer for rival bidder Rolls-Royce to join the project.
The move comes as political wrangling over the engine choice for the new airlifter threatens to hold up contractual talks between AMC and the seven nations that have announced their intention to buy the aircraft. The Airbus military arm had set a deadline of the end of June for the TPI partners and R-R to reach a co-operative deal, but they failed to meet it.
The TPI consortium, led by Snecma and including MTU, ITP and FiatAvio, is putting forward a proposal based on the core of the French company's M88 fighter engine, while R-R has offered a design built around a heavily modified BR700 series core. The rival bidders, however, are under pressure to form a single proposal to satisfy the political requirement to align engine workshare with the A400M production offtake of their national governments.
R-R declines to comment on the TPI proposal, but says: "We can confirm that talks are continuing between R-R and Snecma on a joint solution. Both companies are aware the A400Mengine decision needs to take account of European industrial requirements."
TPI sources say a joint M138 bid could see R-R take responsibility for the high-pressure turbine and possibly the low-pressure turbine also, while Snecma would be responsible for the core, MTU the intermediate spool and Fiat the propeller transmission including the gearbox.
The decision to switch to a three-shaft design followed studies that showed the configuration offered better growth potential, overall fuel efficiency and reliability compared with the earlier two-shaft proposal. The main change is the replacement of the latter's booster stage with an intermediate-pressure (IP)compressor driven by an IP turbine.
MTU chief executive Dr Klaus Steffens will not comment on specific details of TPI's offer to R-R, but says: "We made a very attractive offer to R-R, and we expect a decision very shortly. R-R would bring three-shaft expertise to the party, which could be a valuable contribution."
AMC says it will select the engine when it has received confirmation from customer nations of the number of firm A400M orders to be placed.
"Until we've got a firm number, we are not in a position to negotiate pricing and conditions with the engine manufacturers."
Source: Flight International
