Most interesting visit to AMT Jets
With the AMT Jet’s director www.amtjets.com we discussed the possibility for use of their gas turbines as part of a range extender. This seems quite feasible. They have more turbine sizes, and in terms of power and weight they are highly interesting. The issue is most likely the efficiency of fuel consumption. If fuel consumption to electric power is low than the weight of the system (turbine, generator, fuel tank) is basically the fuel part and the motor weight has little influence. With a efficiency of 5 % fuel to electricity, this still results in a performance of the system of 4.2 times of that of Lithium ion that is rated at 130 Wh/kg. So it is an intereting concept. If fuel efficiency could be enhanced to 15 % we would have a factor 10 better as Li batteries and thus have a flight time of 100 to 120 min! A range extender project would be relatively simple. We could just add the generator cum turbine wheel loosely to the exhaust nozzle. Secondary air would help cool down the temp from the jet. So the turbine wheel could be made simpler and the generator might revs could be more reasonable (not the 92.000 rev/min). We will continue our discussions with AMT jets and see if we can do a joint trial. This will be next year (which starts just over a fortnight from now), as it must be said that currently priorities are to get the craft air born.
Making of test sample and connector
With Barry we made the connector design and he made the first one: beautiful piece. Testing will start next week. Will have a pulling test and a compression test.
Testing of airbag first results
The making of a 5 m diameter airbag parachute has finalized. The issue was to test the explosive first in a bag of larger bag of same material to determine the effect. Well this was the result; a sound explosion with a complete hole in the bag of some 30 cm wide. Apparently the speed of detonation is so quick that the material is inert and just pulverizes. It seems inert as compared to the speed of the detonation. So the idea is now to use a material with slower detonation. For this we need for a pyrotechnics expert or airbag expert to give us the suggestion on what materials to use. If you have suggestions on this, let us know..
Materials for the testing B
For the testing of the Plan b configuration we almost have all the materials. We have to await the Xoar propellers that have been ordered. With Kees we can start the testing. We had a very good suggestion by Forrest F. on the measurement and we will share the results of our tests.