The termination of the agreement between Eclipse Aviation and Williams International, announced the day before Thanksgiving, is seen as a major setback for the Eclipse 500 very light jet program by many observers– particularly (and predictably) by the battalions of skeptics who have questioned the viability of the program since it was revealed in March 2000.

Eclipse CEO Vern Raburn, acknowledging that “we bet the company on the [Williams] EJ22” turbofan, was more talkative than the traditionally taciturn Dr. Sam Williams, who would not elaborate beyond a terse joint statement. On Friday the 13th (of December) the two companies announced they had reached a settlement agreement, but no details were disclosed.

In an interview with AIN last month, Raburn alternated between a promoter’s zeal and undisguised bitterness not only about the failure of the diminutive EJ22 engine to meet his needs but also about how, he claimed, Williams had kept Eclipse in the dark about the realities of the engine’s troubled development.

Looking for a silver lining, Raburn insists the re-engined Eclipse (engine supplier yet to be announced, but the choice is between two Fortune 100 manufacturers) will be a “significantly better aircraft. More important, it’s going to be a radically more reliable airplane. In some ways, I’m more optimistic now than I’ve ever been. When we started this whole thing we had no choice for an engine. Sam [Williams] basically said ‘This is my deal. Take it or leave it.’ There were no performance guarantees. Nothing, just ‘Don’t worry–I can do it because I’m Sam Williams.’

“Well, it turns out he never came close to doing it. Frankly, we are aghast at the way the situation has developed, and our board (the members of which were all nominated by Sam) is similarly aghast. The vote by the board was unanimous to fire Williams. This was not a management-only initiative. The good news is that now we have some really good choices for an engine from manufacturers that are truly capitalized.”

The Eclipse 500 flew just once, on August 26, under the power of its two EJ22 turbofans. Test pilot Bill Bubb was one of relatively few people who knew that the engines were struggling to produce not even half their 770-lb sea-level rated thrust (each) on that hot summer day at Albuquerque (N.M.) International Sunport’s 5,380-ft elevation.

Apart from the issue of thrust, and without going into detail, Raburn also cast grave doubts on the durability of the Williams engine in the sort of high-utilization “air limo” service he envisions for the Eclipse: “It’s a thoroughbred engine. It would have been a Ferrari V12 doing city bus service. The only field maintenance permissible on it was an igniter plug change. For anything else, the engine would have to have been removed and shipped to Walled Lake, Michigan.”

Williams engineers chose an axial compressor because it is light and usually provides better efficiency. However, on such a tiny engine as the EJ22, an axial compressor is hard pressed to function properly, sources outside Williams or Eclipse told AIN. Coupled with the very small size of the blades (said to be 8 mm) on the last stage, tip clearance of even 0.4 mm is relatively too large, causing a significant loss in efficiency.

The knife-edge-thin trailing edge of such tiny blades is also unusually susceptible to wear from the ingestion of everyday environmental contaminants such as dirt, supporting Raburn’s assertion that durability would have been a problem for the Williams engine. Noted one observer: “To an engine that size, a speck of dirt is like a grain of sand, and a grain of sand is like a rock.”

Interesting to note, and providing some insight into the innards and workings of the mysterious EJ22, is the presence of an N3 readout in the Eclipse 500’s avionics and systems management suite. This suggests the engine has three concentric shafts–one for the low-speed compressor/fan (N1) and two more for intermediate-pressure and high-pressure compressors (N2 and N3) downstream. Williams likely chose this configuration for the same reasons Rolls-Royce chose it for the RB.211 high-bypass big-fan engine three decades ago–for compactness and for extracting the maximum power per pound and per cubic inch of engine.

Raburn said he was seeking 820 lb thrust from each EJ22, 50 lb more than the 770 lb that he was expecting Williams to deliver. Williams told Eclipse the EJ22 would be unable to provide the added thrust.

In response to a list of questions about the EJ22, Dr. Sam Williams issued the following reply to AIN: “We are continuing the development of this extremely promising engine, and since the termination of the Eclipse contract we have operated the engine at 817 pounds of thrust (somewhat above the spec level for Eclipse). I have a high regard for the employees at Eclipse, accept their need for a larger, higher-thrust engine and believe they can be successful. Except under confidentiality agreements, we have never revealed information regarding the details of the engine configuration or components and have no plan to do so.”

At press time, Eclipse had revealed neither the identities of the two Fortune 100 companies whose engines it has been evaluating nor the identity of the winner. But two weeks after announcing the termination of Eclipse’s agreement with Williams, Raburn did provide Eclipse 500 position holders with some idea of what airplane they could expect to receive if they hang in there.

• Both potential engine candidates provide 900 lb of thrust. The fan diameter of both engines is identical to that of the EJ22, and both are slightly shorter but fatter due to placement of some accessories in a “more traditional and serviceable location.” Both choices would be heavier than the EJ22, and both pairs would burn about 134 lb more fuel to meet the four-people range guarantees with the EJ22s.

• Weight and c.g.: moving the engines forward by 9.5 in. and relocating all the vapor-cycle system from the wing-root fairing to the nose section will retain the existing c.g. The mtow will increase to approximately 5,550 lb, vs the 4,700 lb envisioned for the EJ22-powered airplane.

• Structure: minor strengthening of spar caps by removing less material during machining. Engine attachment beams move forward. Flaps redesigned to retain low-speed performance at higher weights. Otherwise, no changes anticipated to flight controls, cabin or empennage.

• Systems: fuel system will need to hold 134 lb more fuel, expected to fit within existing wing structure. Simplified electrical system using 28V starter-generator, allowing removal of the two 20-lb power conditioning units required by the power magnet generator of the EJ22. Increased brake disc thickness, and strengthened radial tires.

• Preliminary performance estimates: 377 ktas high-speed cruise; 2,993-fpm rate of climb, 1,100-fpm engine-out rate of climb; useful load more than 2,000 lb; stall speed 64 kt, for landing distance of 2,240 ft and takeoff distance of 2,090 ft.
Raburn estimates the engine change will add $50 million to the cost of certifying the Eclipse, “and that represents an increase of 12 to 15 percent.” So far he has raised $240 million, and he says the majority of deposit money remains in escrow. “Even though this is by no stretch of the imagination fun, I’m really not too worried about being able to finance the company,” Raburn told AIN.

Eclipse does not have to refund deposit money unless it fails to meet guarantees on price, performance and equipment, and schedule, including the following (announced on July 26, 2000):

• Price (June 2000 $), $837,500

• Max cruise speed, 355 ktas (±2.5 percent)

• Stall speed, 62 kt (±4 percent)

• Range, four occupants, 1,300 nm (±5 percent)

• Useful load, 2,000 lb (±2.5 percent)

• Certification, no later than Dec. 31, 2004