Js3 jet catastrophic failure.

On Friday, August 31, 2018 at 11:29:42 AM UTC-4, wrote:
Dave - those statistics are from 2008 so before jets became popular.

I am well aware, and also before many electrics were flying.
I don't know of any serious statistically useful work since then.
Please let me know if anybody has something more recent.

I think jets will eliminate many of the problems encountered with
traditional systems, but the e-systems may eliminate them completely.

Thinking so, and knowing so are terribly different.
Meantime, practical evidence contradicts that hope.

It will be interesting for the project to be re-run with a decades
worth of improvements to the self-launch and particularly sustainer systems.

And it would be great for someone to sponsor such research.

Unfortunately it is extremely unlikely that we'll reach the level
of reliability one might hope for, given the resources available for
testing and refinement of ANY of these systems.
Jet, gas, or electric - same thing.
These are not Toyotas and never will be given financial constraints.

Landing must be Plan A.
If the propulsion system starts, great! But that is always Plan B.
Similarly, putting yourself at risk given engine failure after it starts
is equally unwise. Always plan the flight profile so you have a safe
out when the thing quits or goes to low power.

Be safe out there,
Best Regards, Dave

PS: Some of you know of my work, and courses on software reliability ;-)
Hardware is not so different - lots of testing required!

El viernes, 31 de agosto de 2018, 12:50:26 (UTC-3), Dave Nadler escribió:
On Friday, August 31, 2018 at 11:29:42 AM UTC-4, wrote:
Dave - those statistics are from 2008 so before jets became popular.

I am well aware, and also before many electrics were flying.
I don't know of any serious statistically useful work since then.
Please let me know if anybody has something more recent.

I think jets will eliminate many of the problems encountered with
traditional systems, but the e-systems may eliminate them completely.

Thinking so, and knowing so are terribly different.
Meantime, practical evidence contradicts that hope.

It will be interesting for the project to be re-run with a decades
worth of improvements to the self-launch and particularly sustainer systems.

And it would be great for someone to sponsor such research.

Unfortunately it is extremely unlikely that we'll reach the level
of reliability one might hope for, given the resources available for
testing and refinement of ANY of these systems.
Jet, gas, or electric - same thing.
These are not Toyotas and never will be given financial constraints.

Landing must be Plan A.
If the propulsion system starts, great! But that is always Plan B.
Similarly, putting yourself at risk given engine failure after it starts
is equally unwise. Always plan the flight profile so you have a safe
out when the thing quits or goes to low power.

Be safe out there,
Best Regards, Dave

PS: Some of you know of my work, and courses on software reliability ;-)
Hardware is not so different - lots of testing required!


The only thing that e-systems eliminates completely is the fuel smell in the cockpit.

Chris
Thats a nice video, great work on your plane.
When you have to replace your turbine bearings do you do it yourself or send them out?
What does that cost?

On Monday, September 10, 2018 at 12:49:08 PM UTC-7, Nick Kennedy wrote:
Chris
Thats a nice video, great work on your plane.
When you have to replace your turbine bearings do you do it yourself or send them out?
What does that cost?

For me, last time I checked JetCat charged about $75 per bearing. Service was $300 to 400 total. The problem with doing it yourself is you need dynamic balancer.

On Monday, September 10, 2018 at 2:49:08 PM UTC-5, Nick Kennedy wrote:
Chris
Thats a nice video, great work on your plane.
When you have to replace your turbine bearings do you do it yourself or send them out?
What does that cost?

Nick,

Jet Cat has a support/service center on the east coast that provides the yearly condition inspections and needed parts and service. They have been vary supportive of my installation and typically provide a vary quick turn around. The bearing replacements are provided by Jet Cat as they not only replace the bearings but do a dynamic balance after installation. Most of the bearing replacements and parts have been covered under their 3 year warranty. If I recall correctly the bearing and installation will run around $500 per engine.

https://www.facebook.com/klemencicma..._zeTz0&__xts__[0]=68.ARCtOnZbjk0O1ehdqcbHuVvd_i3GfgPkQh2yAgOsYWzmQv GbyUdM0NnEgfRmfodrTxo59sRvkOaFps-11uPW3zAmElpyXsztHz

Hang Glider Pilot getting right into the jet power

On Thursday, August 30, 2018 at 4:46:35 AM UTC+2, Charlie Quebec wrote:
In the last east issue of Gliding Australia there is an incident report shown below.
During the course of a cross country flight, the pilot elected to start the jet sustainer to self retrieve.
The engine started normally, and the pilot tracked for the home airflield The engine failed catastrophically
830ft. AGL and a safe outlanding was conducted.
Things that make you go hmmmm...

I own and operate an EASA certified JS1 w/ an M&D jet sustainer engine in the Alps. I have found the system very reliable, but I don't trust it to save me from an outlanding or, worse, being trapped down low in an alpine valley.

With one exception I kick myself for this very day, I have always started the engine within easy range of an airport. Often I'll start the motor earlier to avoid a situation where I am forced to fire it up down low, when my only option is a field.

I am perhaps too prudent but I fly over some pretty nasty territory. Even when it looks flat, it's not. And the JS1-21m requires some care to land safely and short.

The nicest thing about the jet vs. classical sustainer is this - if it does not start, you have almost 0% added drag with the thing hanging out the fuselage. The proof is in the pudding...

Shortly after I received the beast, I fired up the motor before a cross-country flight to re-assure myself it would start. I usually don't let the automated system retract the motor when the EGT sensor says the hardware is 50C. I do that manually and usually wait for the equipment to cool to much lower tempertures before stowing it.

I must have been distracted with ATC or something. I was flying around the Lyon TMA that day. I shut the engine system off withough retracting the engine. I managed for fly 650 km with the jet windmilling. I did not even notice.

As for fuel, I usually use BP excellium and Cross T 2 stoke oil. I wish I could buy the Shell Gas-Diesel in my kneck of the woods. I've never noticed any start up issues related to altitude or temperature. Then again, I can't imagine any reason why I might start the beast up at 3000m. I can glide at least 100km on that without the motor.

Yes, the mountains are high in the Alps but the valleys are quite low and the density of airports is more than adequate. I can imagine a high and hot start in South Africa or the Western US. Different conditions.

A+

I've been digging around trying to find out what the process has been for pilots that have added jets other than the MD-TJ 42. This group seems to have a lot of knowledge on this niche subject. The jets are coming down in price and getting a lot more reliable to start, so it seems it would be a more considered option for a lot of pilots. Are there many self-installs, or are there a handful of companies that specialize in the retrofit?

On Monday, October 26, 2020 at 6:33:02 PM UTC-4, wrote:
I've been digging around trying to find out what the process has been for pilots that have added jets other than the MD-TJ 42. This group seems to have a lot of knowledge on this niche subject. The jets are coming down in price and getting a lot more reliable to start, so it seems it would be a more considered option for a lot of pilots. Are there many self-installs, or are there a handful of companies that specialize in the retrofit?

You didn't say where in the world you are but for the US, Bob Carlton in Moriarty would be my first choice to call, if I wanted to have 'my ride pimped out' with a jet.

Uli
'AS'

P.S.: Bob - as soon as that lottery thing works out for me, I'll be giving you a call! ;-)

I'm in the US and familiar with Bob. What he does is fantastic, but I'm more curious about some less expensive, less pimped out options. Everything I've seen of his so far uses PBS engines which are extremely expensive. The Jetcats and some other options are much more affordable and I know there are pilots that use them.. I'm wondering how they went about the retrofit.