Jet turbine reliability

I witnessed a jet-powered glider at the EAA event in Oshkosh.

My immediate thought was we could not allow them to fly at our gliderport.

The noise was beyond imagination. The neighbors simply would not tolerate the noise.

Tom Knauff

On Monday, June 1, 2015 at 7:58:58 PM UTC+2, wrote:
I witnessed a jet-powered glider at the EAA event in Oshkosh.

My immediate thought was we could not allow them to fly at our gliderport.

The noise was beyond imagination. The neighbors simply would not tolerate the noise.

Tom Knauff
You make a fair point. JS1 is not a self launcher so in all probability the jet will only be used out over deserted farm land far from the home airfield.

On Monday, June 1, 2015 at 1:58:58 PM UTC-4, wrote:
I witnessed a jet-powered glider at the EAA event in Oshkosh.

My immediate thought was we could not allow them to fly at our gliderport..

The noise was beyond imagination. The neighbors simply would not tolerate the noise.

Tom Knauff

Mr. Knauff, I'm guessing you are referring to Bob "Airshow Bob" Carlton's Super Salto or BonusJet or SubSonex aircrafts which are all self launching and/or "show center" aircraft. You are correct that they are loud.

However, comparing one of Bob's aircraft to a JS-1 jet sustainer is an apples to oranges comparison. A sustainer jet has a totally different footprint and is not purposed to continually operate in the "cylinder" of a gliderport. Given a choice, your rural Ridge Soaring neighbors (or any other airport neighbors) would probably prefer the occasional passing "swoosh' of a sustainer jet as opposed to the frequent roar of your daily tow plane operation.

I'll believe it when I hear it.
Tom

Was given a JS1 engine start demo at Lake Keepit, it's pretty simple. Correction, very simple.
We were right next to it, in an open hangar and it wasn't deafening.
Also witnessed a powered JS1 low pass, quiet compared to a straight-pipe exhaust airplane. It is loud compared to a normal unpowered glider low pass.
While putting the glider away today, there were two (52 Lb thrust) turbine runs after overhaul at JetCat. Believe an air compressor is as loud at an equal distance, much louder if there's a die grinder involved.
Flown with Bob Carlton in the Bonus Jet. With the same (247 Lb thrust) TJ100 as used on the Salto it is quite a bit noisier than a JS1J (92 Lb thrust) but still not hideous when you consider it's a self-launcher that can out-climb most towplanes. Perhaps it's just odd to look at a glider and hear that sound.
Jim


On Monday, June 1, 2015 at 12:37:12 PM UTC-7, wrote:
I'll believe it when I hear it.
Tom

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.

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.

Anyways, Jim, I think once you get used to starting a turbine you'll find its very reliable. But, it can fail to start.. things like a failed thermocouple is all it takes for the start sequence to halt. Also too much air in the line can do it if the lines weren't purged properly... clogged line filters can create a low rpm fail start. Otherwise, properly maintainted they work great with a well charged starter/ignition battery.

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.