. Are Watchkeeper and Heriti the best UAVs the Army can purchase? http://en.wikipedia.org/wiki/BAE_HERTI http://en.wikipedia.org/wiki/Watchkeeper Herti is a hugely overweight Fregati glider, and you cannot double the design-weight of an airframe without serious control problems (a 747 taking off at 800 odd tonnes??). The Herti weighs some 750 kg with a max payload of 150kg, but does not give an endurance (the most vital statistic). However, based on the engine and weights given, we can assume 19hrs. The Watchkeeper looks like a cruise missile with plank wings and shopping-trolly undercarriage, with all the problems that entails. Again, info is sparse, but working from the weights and the engine being used, endurance is likely to be 15hrs. The quoted 30hrs in Flight International is spurious, because the numbers just don't add up. (Unless this is a zero payload figure). But is this the best we can do? The Gem7, which was demonstrated at Aberporth this year, can out perform these UAVs in all respects. Based on a lightweight single-seat glider, it is: At 275 kg, nearly a third of the weight of Herti. A max 100kg payload is quite impressive. A max endurance of 48 hours is unbeatable (at 50kg payload). In addition: The Gem7 airframe has a glide ratio of 32:1, twice as good as the Herti and Watchkeeper, which is why it is so efficient (long endurance). You only need to look at Watchkeeper, with its long fuselage and pyloned plank wing, to know it will not fly efficiently. The Gem7 payload sits on the CofG, so mission changes are simple. Try that with Watchkeeper, and the thing will either end up on its nose or tail. The airframe can be dismantled and packed away in a trailer by two people inside 5 minutes. Can either of the others do that? At 275 kilos, the Gem7 is fully air-transportable into theatre. Approach speeds are far lower, for easy take-offs and landings. The baloon tyre can ensure operations from any farmer's field, something that the tricycle-wheeled Herti and Watchkeeper would find very difficult (especially with shopping-trolly wheels). The T tail allows for landing in crops. The airframe is supposedly less than a quarter the price of a Watchkeeper or Herti. Can the Army not do better than the choice they have made? Or are they going to end up with another very expensive Phoenix? http://www.spyflight.co.uk/phoenix.htm (This critique of the Phoenix is worth reading, simply for the hilarity of it.) .