Jet turbine reliability

On Tuesday, 2 June 2015 21:40:56 UTC+3, wrote:
On Tuesday, June 2, 2015 at 7:34:47 AM UTC-7, krasw wrote:
Surely jet engine cannot be more unreliable than Solo two-stroke that you need to dive to start. If it would, you would be lucky to start it even once.

Solos don't need a dive to start. You can start them that way if your starter battery is dead but normally you never need to do this.


I was obviously talking about turbos, which you have to dive to start. There is only handful of turbos with electric starter (for some unimaginable reason).

There on single moving (rotating) part in a turbine. Compare that to shaking two-stroke held together with a bucket of tiewraps.

That's what I thought.

On 6/2/2015 7:47 PM, wrote:
They are MODEL engines and are not "man rated" by the FAA. There are several YT vids showing how they are built and assembled. Watch these and then determine if you ever want to put your "skin on the line" using one. By comparison, the Williams FJ-44 is a small TURBOFAN originally built to power US cruise missiles. It had to demonstrate extreme reliability before it was FAA certified and man rated for use on very light business jets. Not to mention it was originally designed to stringent military specs. Bottom line again, these are model TURBOJET engines. Never put your safety/life in a position where their reliability matters.

--
Dan Marotta

OK, then.

On 6/2/2015 11:31 PM, wrote:
... and I'd be surprised if some of the new crop of small European turbines weren't being made with an eye on the expanding UAV market - I can't see how the time and money being spent on them can be recouped in the glider market alone.

--
Dan Marotta

Let's hope that that single rotating part has been made and assembled with
the proper controls.
Something rotating at 100,000 rpm about 3 feet from your head had better be
good.
Contained failure would mean bullets being fired at your fin/tailplane.
Uncontained failure and you had better have a good parachute, assuming you
survive the explosion!!

There on single moving (rotating) part in a turbine. Compare that to
shaking two-stroke held together with a bucket of tiewraps.

Originally Posted by Dan Marotta

That's what I thought.

On 6/2/2015 7:47 PM, wrote:
They are MODEL engines and are not "man rated" by the FAA. There are several YT vids showing how they are built and assembled. Watch these and then determine if you ever want to put your "skin on the line" using one. By comparison, the Williams FJ-44 is a small TURBOFAN originally built to power US cruise missiles. It had to demonstrate extreme reliability before it was FAA certified and man rated for use on very light business jets. Not to mention it was originally designed to stringent military specs. Bottom line again, these are model TURBOJET engines. Never put your safety/life in a position where their reliability matters.

--
Dan Marotta

No Dan, the TJ42 turbine used in the JS1 Revelation has been developed from scratch specifically for the sailplane market. They have never been used in anything but sailplanes and comprehensive testing has been completed for certification. I have had the privilege of visiting the factory in Northern Germany and was very impressed with the dedicated plant and the professionalism of the staff.

Brett

Hazard is to the rear engine and its mounted behind you. I remember seeing that some of these also had a containment housing. So, I think they have addressed the issue. But it makes one heck of a pop if they do shed a blade! This will be about the only time a turbine will vibrate as it winds down..

Having flown a land-mower piston engine for quiet a while (ASW-24E) and
now having decided to go for the JS1 jet, I consider this a major step
forward in terms of safety.

Make no mistake, none of these engines is an aircraft engine in the
sense used by airplane pilots. You should always expect that it will
fail to start, or worse, quit at the most inappropriate time every
single time you use it. Not doing so is simply foolhardy.

The difference with the JS1 jet (and I imagine the similar shark
installation) is that if the engine does not start, you are not stuck
with a huge profile in the airstream and a glider that is descending
like a rock. You simply flip a switch and about a minute later you are
either climbing or continuing towards a perfectly normal off-field landing.

This is much closer to the idea people have when they buy into a
self-launcher or turbo, only to discover later that the reality is very
different. It is a great sign of progress that now jet and electric
technology are making this much more of a reality.


On 03/06/2015 04:47, wrote:
They are MODEL engines and are not "man rated" by the FAA. There are several YT vids showing how they are built and assembled. Watch these and then determine if you ever want to put your "skin on the line" using one. By comparison, the Williams FJ-44 is a small TURBOFAN originally built to power US cruise missiles. It had to demonstrate extreme reliability before it was FAA certified and man rated for use on very light business jets. Not to mention it was originally designed to stringent military specs. Bottom line again, these are model TURBOJET engines. Never put your safety/life in a position where their reliability matters.

That was Brett that wrote about the FJ-44, not me.

On 6/3/2015 2:57 PM, Brett wrote:
Dan Marotta;904892 Wrote:
That's what I thought.

On 6/2/2015 7:47 PM, wrote:-
They are MODEL engines and are not "man rated" by the FAA. There are
several YT vids showing how they are built and assembled. Watch these
and then determine if you ever want to put your "skin on the line" using
one. By comparison, the Williams FJ-44 is a small TURBOFAN originally
built to power US cruise missiles. It had to demonstrate extreme
reliability before it was FAA certified and man rated for use on very
light business jets. Not to mention it was originally designed to
stringent military specs. Bottom line again, these are model TURBOJET
engines. Never put your safety/life in a position where their
reliability matters.-

--
Dan Marotta
No Dan, the TJ42 turbine used in the JS1 Revelation has been developed
from scratch specifically for the sailplane market. They have never been
used in anything but sailplanes and comprehensive testing has been
completed for certification. I have had the privilege of visiting the
factory in Northern Germany and was very impressed with the dedicated
plant and the professionalism of the staff.

Brett





--
Dan Marotta

I would expect the QA on these units to be better than that of the typical model turbine. You'll be much less likely to run into a dud here. What is the retail price of this 420N turbine with ECU?

"They are MODEL engines and are not "man rated" by the FAA. There are several YT vids showing how they are built and assembled."

A very inappropriate comparison. It's akin to comparing an experimental aircraft with a certified, high capacity transport category aircraft.

The Williams has undergone destructive testing, blade containment testing, is certified for flight into known icing, use on ground, use in rain etc etc.

Using M&D's engine as an example, it has no accessory gearbox so no lubrication; you add extra oil to the fuel like a 2-stroke. It has no electrical system thus no self-sustaining fuel delivery nor command and control. Both of those functions are powered by the battery so it's essential to leave a battery untouched 'for Justin'. It's not approved for ground operation other than maintenance nor for flight in rain. It's a simple, elegant, low weight, low drag thrust source for sustaining. A 'getcha home jet' with only the operating principle as a similarity with Williams and other certified products. And thanks heavens for that! It would be too large, too heavy and too *EXPENSIVE* otherwise.

CJ