dunno if they're armed or not, but there are four of them (at least) used in place of the drones for surveillance This gives the background - and a photo of a USA one
US, UK deploy manned unmanned aircraft to save bandwidth ? The Register
In UK parlance an FLKA = Shadow R1
Hawker Beechcraft advert for them at
Hawker Beechcraft Military and Special Mission: Surveillance
Theres more background in relation to todays news report at
UK's Reaper flying hunter-killer fleet 'to double' ? The Register Seems the RAF is to double its number reapers from five to ten.