|Base Hull||Blackbird Class|
|Drive Type||Hybrid bussard turboram|
|Flag of Record||Crystal Millennium|
|Primary Crew||1 x Pilot,|
|Other Crew||1 x Mission Specialist|
|Auxillary Vehicles||L'il Abner|
|“||The only way which leads us to a quick development in human flight is a systematic and energetic practice in actual flying experiments.||”|
— - Otto Lillenthal
|“||Even the best computer simulations can only really confirm the bias's they've been programmed with. They only allow for the stuff you knew before you started. But you never really know if something's actually going to work until you try it in the real world..||”|
— - Mackie Jaguar
Pretty much every major aerospace manufacturer these days can boast their own dedicated skunkworks, churning out those unique X-craft and one-off prototypes to trial and test new aerospace ideas. It costs a lot of money to keep a good skunkworks going so it's really only something the larger concerns can afford - the little guys have to satisfy themselves with some sim' time and some small-scale testing, while hoping they get their models right. Aerodynamic and etherdynamic modelling takes time, money and several large supercomputers to get right.
XR-71 came about due to an unsolveable stability problem with the RF-47 prototype, which resisted all attempts at software modelling. The RF-47 programme was saved by just five days test flying of a mock-up wing strapped to XR's dorsal mount.
She's since been modified a great deal. The most obvious differences being an ogival nose-cone, and three additional ventral fins under each nacelle and along the centreline. The dorsal docking mount has been modified with control umbilicals and fuel feeds to fit an auxiliary engine along with structural hardpoint adaptors for other hardware, including spacecraft structural elements or test drones. The forward crew cabins have been converted into fuel tankage  to feed the auxiliary engines. The rear tanks still feed the main engines. The weapon and sensor mounts in the chines have been swapped for test and datalogging equipment, with spare bays for any control hardware required for the test at hand.
The spaceframe was constructed by a client as part-payment. It is a drone which can dock with the dorsal mount. It can only carry small payloads and light sensor loads, but can carry them at speeds higher than XR-71 itself might be capable of. The original test-engine was removed prior to delivery.
It can also be used for proof-of concept high-speed propulsion testing. The modified bussard turborams on XR itself were based on designs tested on L'il Abner.
- Although intentionally built without a shipmind, she's developed a notorious unspoken personality.
- Stripped to the frame and modified, but still very much a Blackbird. It's not happy if it's not doing what it was born to do. Let's go out there, go fast and learn something 'new'.
- She's an attention seeker at the best of times. Spend too long with your head out of the cockpit and she'll do something interesting. Like unstart an engine, throw an overheat warning or jam a bypass door. But never when it's actually a hazard to the spacecraft.
- Unarmed. Only capable of outrunning any attackers. But capable of outrunning almost any attacker. It cannot be armed - dedicated weapons will not operate. 
- XAVIER. A modified autopilot, programmed with details the test at hand to assist the pilot in flying the correct test-profile, compensating for the affects of the additional hardware using real time data from the onboard loggers. About the only deference to pilot assistance.
- In many ways, she's the opposite side of the same coin of the Blackbird myth. A challenge to fly, even on a ferry flight, demanding mastery and a mind one step ahead of the jet. Not a machine for the faint hearted or ham-fisted. 
- Available for rent, charter or otherwise by any reputable individual. But, you break it, you buy it.
List of known Clients
- Avro-Mars Engineering
- Shin-Nakajima Aerospace
- 'A mundane client based out of Palmdale, California'
- Revealing an alarming tendancy for the wing to warp in positive feedback to the controls above a certain speed, rendering it utterly uncontrollable.
- Or converted back into fuel tankage, as on the original OXCART-types
- Or, acts as a nice little earner for her owners...
- Test items do work appopriately.
- Very much a manufacturer quirk.
- And, of course, definitely not the only Blackbird type operating in this role