High-altitude, LOW AIRSPEED engine

[MaverickSawyer]

We've got a lot of high-speed, high altitude engines available right now. It's pretty good to have a wide variety of them, too. But there's a niche slot that, as far as I'm aware, hasn't been looked at: High altitude engines meant for subsonic high endurance aircraft. Something that one could use to loiter over an area for hours on end, or to perform detailed mapping of a particular area without the cost associated with a specialized satellite.

Granted, high altitude performance is also highly dependent on airframe design, but I've been disappointed with the engines I have access to right now. The J-33 can push my Angel 1 aircraft up to 9720 meters... but not a meter more. Need to try the Whiplash engine, but I suspect that it'll have the same issues at altitude and low speed as the Wheeley.

So, what I'm looking for is an engine that can maintain, oh, 30kN of thrust?, all the way to 15km altitude while remaining under 250 m/s.

EDIT: Never mind. Whiplash CAN provide me with the performance I seek. Mods, please lock and archive this request.

Edited August 9, 2015 by MaverickSawyer