Wednesday, May 28, 2008

Air Force/Scaled Composites PDE Long-EZ heads for museum

Now that the U.S. Air Force has announced that yet another innovative Mojave product, a Long-EZ powered by a pulse-detonation engine (or PDE), is going to be enshrined in a national aviation museum, I thought it appropriate to dig out and share my images of this unique machine. The PDE was developed by a team from the Air Force Research Laboratory, and the Long-EZ was subsequently selected as an inexpensive testbed aircraft to try it out on. The engine was built by the team from "off-the-shelf automotive parts" in 2002.

What makes the PDE so unique is instead of burning fuel, called deflagration, to get propulsion, air and fuel are mixed, ignited and detonated in controlled explosions inside open-ended tubes that look like exhaust pipes. When detonation moves through the tubes it creates a supersonic shockwave that continually pulses and generates thrust.

Prior to the initial ground runs at Mojave, tenants were warned of the noise that the tests would make...and noisy it was! At well over half a mile away, the PDE sounded like a pipeless Harley on steroids parked right next to you. Development of the project continued on an on-and-off fashion for several years (the photos on the left and below were taken in 2004).

According to the Air Force press release which quotes Fred Schauer, AFRL Propulsion Directorate, "A major drawback that kept the team from flying earlier was the excessive drag caused from all the accessories hanging under the aircraft. This was overcome by placing an aerodynamic cowling over the PDE, which was designed by Scaled Composites. The engine also endured 100 hours of durability ground testing and 30 hours of airframe integration tests."
Finally, on January 31, 2008, the PDE-powered Long-EZ made its first and only flight, down Mojave's 12,500-foot Runway 12. The initial takeoff was by means of a small standard jet engine, and after the aircraft lifted free Scaled Composites test pilot Pete Siebold shut down the jet and fired off the PDE. The noise was unmistakeable, as the Long-EZ cruised at 60 to 100 feet over the runway, and hitting 120 knots. Just past the control tower and the main runway intersection, the PDE was shut off and Pete safely touched down and rolled to a stop before the end of the pavement. Though the aircraft had been towed out to Runway 12, it taxied back to Scaled's hangar under its backup jet engine power. The engine was developed and manufactured in-house by the AFRL Propulsion Directorate's Turbine Engine Division, Combustion Branch and its on-site contractor, ISSI. The successful flight test was a joint AFRL effort that included the activities of AFRL Propulsion Directorate for PDE developmental research and the propulsion package; AFRL Air Vehicles Directorate for structural, aero and acoustics; AFRL Human Effectiveness Directorate for exposure limits and acoustic protection, AFRL Materials and Manufacturing Directorate for structural materials; and Scaled Composites, Inc. for vehicle integration and flight testing.

Now, comes the announcement that after just the one flight, the record-setting plane will be displayed at the National Museum of the U.S. Air Force at Wright-Patterson AFB in Ohio. "The aircraft is in our restoration facility awaiting transfer for exhibit in our Experimental and Flight Test Gallery -- a most appropriate location for such a fine example of innovation," said senior curator Terry Aitken, National Museum of the U.S. Air Force, in their May 16th press release. So what's to come for PDE technology? "The increased thrust could be capable of powering future aircraft up to speeds of Mach 4, or four times the speed of sound, and beyond. According to Fred Schauer, AFRL Propulsion Directorate, the PDE can be combined with other engine cycles, such as turbines, rockets, or hypersonic scramjets, to optimize flight envelopes. 'This engine offers the capability of static to near hypersonic flight with good supersonic efficiencies. Pulsed detonation engines could make sense for missions that require efficient supersonic cruise and/or boost from low to high speeds,' Mr. Schauer said. Another plus for the engine is its ability to run on a variety of fuels and maintain near-constant-volume combustion, which makes it highly fuel efficient." Of course, they'll have to do something about that's rather far from the up-and-coming Stage 4 aircraft noise standards!

Click here for the complete Air Force press release.

Thursday, May 22, 2008

Total Eclipse

Eclipse Aviation's latest innovation, the ECJ (for Eclipse Concept Jet) is visiting Mojave for a few days during its flight test program. The ECJ was first announced at the 2007 Oshkosh AirVenture as a concept for a 4-place "personal jet", and at the time Eclipse's CEO Vern Raburn said that within 12 months the company would announce whether the aircraft would be going into production.
This proof-of-concept version is currently unpressurized, but the goal is to have an aircraft capable of 345 knots and a 41,000 foot service ceiling. According to Raburn, the ECJ has about 60% commonality with the Eclipse 500 VLJ, including the Avio NG, the computerized system which controls the autopilot, FADEC, air data system, and flap and landing gear actuation. Power is produced by a single Pratt & Whitney PW615F turbofan engine, which produces 1,100 pounds of thrust.
While it remains to be seen whether this innovative, all-composite jet will turned into a production model, one thing is certain: the designers (Eclipse partnered with Swift Engineering to design and build the plane) came up with a concept that looks like it's fast even when simply sitting in the hangar.
(Many thanks to the folks at Eclipse for letting me shoot such a gorgeous plane!)

Monday, May 19, 2008

CO 747 Farewell - End of an Era

The end of an era was quietly marked today by the final scrapping of the last of the three Continental Airlines 747s here. For the past 10 years, a trio of retired Continental 747s has languished in Mojave's boneyard, changing hands repeatedly, and appearing in a number of TV shows. N33021 was the first to meet the scrapper's shear back in 2004, N14024 was cut up a few months ago and lastly N17025 has been turned into scrap metal.

Continental's fleet number 025 was a 747-238, serial 20535 and was the 217th 747 to roll off the Boeing assembly line in 1973. She first flew for Qantas as VH-EBF for a dozen years, before finding a home with People's Express, which then merged into the Continental system. When CO phased out their 747s, 025 flew to Mojave for storage.
Left: N17025 enjoying a quiet desert sunset in December, 2003.
Below: All three CO 747s together, with N33021 in the foreground in the early stages of disassembly, again in December 2003.

Friday, May 16, 2008

Flight of the Rocket Racer!

This afternoon, as Mojave baked in one of the season's first really warm days, with the wind strangely out of the northeast, XCOR Aerospace rolled out the Rocket Racer prototype for another of its early test flights. Piloted by retired Shuttle astronaut Rick Searfoss and with a second person also onboard, the highly modified Velocity SE was towed into position on Mojave's Runway 30, performed a 3-second engine test burn, and then took to the sky, climbing steeply to the north. As a part of today's test flight, the rocket engine was shut down and relit twice, before Searfoss glided the aircraft in for a landing in a stiff crosswind.

The Rocket Racing League is envisioned to be a NASCAR-style series of races in which rocket powered aircraft fly a pylon course made more "interesting" by the inclusion of required aerobatic maneuvers at different points in the race. Rocket Racing, Inc, recently acquired the airframe's manufacturer, Velocity Aircraft, and all the racers will be based on this aircraft type. Race teams will have the option of choosing either an XCOR engine or one produced by Armadillo Aerospace. XCor's engine, the XR-4K14, burns kerosene and liquid oxygen to produce 1,500 pounds of thrust.

For more information on the XCOR engine, see

Thursday, May 1, 2008

Every 15 Minutes

Every 15 minutes someone somewhere dies from an alcohol-related traffic accident, and our youth are especially susceptible. In order to make high schoolers dramatically aware of the dangers of drinking and driving, the California Highway Patrol sponsors a program called Every 15 Minutes through local high schools.

Today was the first day of the two day program at the Rosamond High School, the next town over from Mojave, and Mojave's Mercy Air 14 participated along with Kern Fire Station 15, Hall Ambulance, and of course the local CHP and Sheriff's office.

The program begins with a staged drunk driving head-on accident, with four of the high-schoolers participating, one of whom is "arrested" (complete with booking process!), and the other three are badly "injured" and have to be extricated. Two of the students' injuries were assessed as meeting trauma criteria, and so Mercy Air's 412 arrived on-scene at the school's football field, where the students were loaded aboard and flown off. In the script, one of them subsequently dies in the hospital, and so the second day of the program involves a funeral at the school. According to the reports of staff, today's accident, even though staged, and the emergency response to it, had a profound affect on the kids. Let's hope some lives were saved through this today!

If you want more information, please visit the CHP's program website, or you can download a PDF brochure at: