fes ot jet (pros and cons)

Richard,

The failures to start that I'm familiar with are all JS-1's

On Thursday, August 8, 2019 at 7:28:30 PM UTC-7, Tony wrote:
Richard,

The failures to start that I'm familiar with are all JS-1's

It was discovered that the M+D jets were being delivered within tolerances, but reliability could be improved by using more finely gratuated feeler guages.
Essentially: The tolerances were too wide. Keep the alignment as close to the specification as possible to achieve a more reliable start.
Jim

The manufacturing tolerances issue in M+D jets was what was related to surging after the start in South African conditions and before they reached the certification stage IIRC. My early pre- certification jet didn't have that problem. Over 135 starts during my time of ownership (mostly ground and air tests in both Scotland and South Africa) what I did find was that it didn't start reliably in cold UK conditions with diesel fuel but was fine with jet A1, whereas in SA it was very unreliable on jet A1. At the suggestion of the factory I started using premium synthetic/petrochemical diesel fuel (Shell V-Power Nitro) and with that it started 100% in both cold UK and hot/high SA. That stuff contains no biofuel btw.

The other thing I learned myself was to use an additive such as Biobor to prevent microbial overgrowth from clogging the fuel filters. 1 ml added to 10 litres was all that was required.

Originally Posted by

The manufacturing tolerances issue in M+D jets was what was related to surging after the start in South African conditions and before they reached the certification stage IIRC. My early pre- certification jet didn't have that problem. Over 135 starts during my time of ownership (mostly ground and air tests in both Scotland and South Africa) what I did find was that it didn't start reliably in cold UK conditions with diesel fuel but was fine with jet A1, whereas in SA it was very unreliable on jet A1. At the suggestion of the factory I started using premium synthetic/petrochemical diesel fuel (Shell V-Power Nitro) and with that it started 100% in both cold UK and hot/high SA. That stuff contains no biofuel btw.

The other thing I learned myself was to use an additive such as Biobor to prevent microbial overgrowth from clogging the fuel filters. 1 ml added to 10 litres was all that was required.

I have a JS-1C TJ as well. I had no issues with starts but rolling the throttle up through 45% produced a Flame Out. Turned out to be tolerance issues and was addressed by M&D very satisfactorily. They turned it around quickly and I haven’t had an issue since. Engine test in the start cylinder for every flight, and the occasional beat-up upon request, and not a failure since its return. I’ve used Jet-A and Diesel with good results but rely on Diesel due to availability around contest sites and M&D’s recommendation. 60-seconds to full power and the equivalent drag of your gear make it pretty attractive. 250-km saw-tooth range is a bonus as well. But yes, there is an airport, or good field within range on every start.

Rick
NR

Jet - we have heard opinions on reliability.

How many cases of Fes not performing?

Any experiences, anyone?

S