Turbojet Engines

Compact Turbojet Engine Makes Supersonic Testing Affordable

Starkey Aerospace is a fresh company formed by University of Colorado Boulder assistant professor Ryan Starkey. Starcor has been working on a small, low-cost, supersonic unmanned aircraft. New company strives to produce the 110 lb. Unmanned Aircraft which was inspired by the X-15 design. Starkey hopes to provide a reusable and disposable flying platform for high-speed flight testing, penetrating storms and military reconnaissance. Under $100,000 machine will so affordable that losing the vehicle would not jeopardize the program. The Gojett project has been active at CU-Boulder for about three years now and is slowly transformed into Starcor.

}The project is funded sufficiently to develop an airframe and its efficient jet engine as well as to take its prototype through to taxi test, however it tries to raise funds to finance flight testing and producing of first aircraft capable of transonic and supersonic speeds. Starkey is planning a test flight in 2013. The engineering test is scheduled to be performed in April of 2012. By July of this year aircraft’s engine will be modified into US Microjet AT-450 turbojet, with following ground and taxi testing in August or September. However the AT-450 may be used only for low-speed flight testing. Starcor intends to install a modified and more powerful AMT Netherlands Titan engine for possibly supersonic speed testing between December 2012 and February 2013.

Owner claims that the biggest problem they have is that small turbojet engines are not fuel efficient. Initially, the Gojett project planned to develop a small turbojet by improving the production turbojet engine AT-450; the goal was to increase its thrust-to-weight ratio. Original turbojet could be used for subsonic speed tests, but definitely lacks the thrust sufficient to overcome the transonic drag. This is how the plan to develop and the Titan were born. The company’s own new turbojet engine, the L-FX00, is a lubrication-free jet with thrust of about 200 lb. Other details include variable diameter nozzle, afterburner and fluidic vectoring of thrust. The intent is to double the fuel-efficiency and thrust of production turbojet engine without the increase of the frontal area of the turbojet engine. The turbojet engine resource also, called time between overhaul, will exceed 1,000 hours, which is about 20 times higher than TBO of currently manufactured average small size UAV turbojets. Ryan is confident that the new fuel-efficiency and higher thrust-to-weight ratios will be demonstrated with a modified AT-450. Company is working with the US Naval Research Laboratory to prove the extended time between overhaul, with NASA Gleen the lubrication-free capability and with NASA Langley thrust vectoring. The thrust-vectoring tests are expected to be complete in a month. The total length of UAV will be 5.8ft long and its delta wings will span 4.2ft. Flight will be directed by elevons and the thrust-vectoring system powered by the fluidic-injection. The afterburner will be fed by the pitot inlet. The first machine will target Mach 1.4, but the ultimate goal is to reach Mach 1.7.

Company needs more money. They are looking for $50,000 to finish the prototype, but more is required to finance first high-speed flight testing. That is why the UAV will be first tested with the modified AT-450, and only later with the Titan, before the L-FX00 leaves the ground. Owner is determined not to install the new turbojet engine until all the issues are worked out, though he agrees that money would speed up the process. He says: "Breaking a modified COTS engine is cheap, but breaking a prototype is not, especially coupled with an expense vehicle."

Reference: Starkey Aerospace, University of Colorado.