I have now had a chance to put the 'CE' TSP L-1, L-2 and L-2 HP motors on the test rig. Most measurents were done in duplicate just to check the first run. I estimated the usable 'burn time by the sound the motor made, waiting for the moment I would actually launch a model on the flying field. Here are my results:
L-1 133 +- 13 mN 10 sec
L-2 183 +- 17 mN 12 sec
L-2HP 335 +- 33 mN 12 sec
These results are not too dissimilar to Terry's results (but note the 'burn times' which are, I admit, somwhat subjective and shorter than Terry's) . My L-1's appear a bit more powerful than Terry's. Though this is pleasing (this thrust is just perfect for my profile F-100 Super sabre) I wondered what the effect of boring out the nozzle from 2mm to 2.5mm, to (hopefully) make these TSP L-1s sutable for, say, a Jetex Wren. This gave
L- 1 (2.5mm nozzle 1) 120 +- 22 mN 12 sec.
This was 'interesting', so I tried a TSP L-2 with a 2.5mm nozzle:
L-2 (2.5mm nozzle) 133 +- 17.5 mN 14 sec.
Such a performance is perfect for some of the classic Jetex scale designs, and I look forward to Terry's more comprehensive 'boring out' experiments.
General observations:
The run times are distinctly shorter than we have got used to with Rapiers and Piotr's 'pre CE' motors. This is an inevitable consequence of a larger nozzle diameter resulting in of a lower Specific Impulse. This we can live with - there will be no more wretched 'burn throughs' - and (a) it will keep our models in smaller flying fields and away from trees etc and (b) us old guys will have less far to walk to retrieve models
Another consequence of the lager nozzles is a rather fiercer exhaust flame:
Above: a TSP CE motor on song. It was a dull on the day of the tests and the exhaust flame is bright. Hmmm ... We may find ourselves changing our motor trough linings and thrust tabs more often with these motors!
Motors did not always ignite using just a fuse: some abraision of the propellant with a 1mm screwdriver helped a lot. Ignition using a modified Cord Zap with four AA batteries worked every time.
As Terry has noted, the consistency of the motors during a run and the repeatability of examples (note the acceptable standard deviations) was good and far better than we have seen with Rapiers.
I'm looking forward to trying these motors on the flying field. I shall be soon writing an article for' Aeromodeller' about all these exciting developments - new motors, reliable distribution, new suitable models from both VMC and Piotr Tendera to suite these motors, progress with igniters. So, if you want me to include your own comments and observations in said article, start posting!