Js3 jet catastrophic failure.

I'm actually reporting on turbines less than 5 years old and it was a ceramic "glow plug"(igniter) that failed. In the case of the Jetcat starter motor I was able to fix that myself which was nice.
Darren

I'd be curious to know which Jetcat models. The P300 and P400 have the ignitors situated differently than the smaller engines and I found that the wrong location contributed to faster wear. Also, the most typical reason for failed ceramic ignitors (that I've experienced) was from too much voltage. The ignitors that Jetcat uses are very happy with 6V and that's plenty for consistent starts but I know of a lot of guys that crank theirs up. Was the starter problem perhaps a jammed open bendix that was holding the o-ring against the compressor nut? Or were they disengaged and the motor itself was jammed up? The former is always an easy pre-flight fix but the latter is obviously the motor. If that was the case, is it brushed or brushless?

I'll admit I'm a bit of a jet addict and always trying to eliminate their nuances. Sorry if this is the wrong place to be posting the technical stuff but maybe it will help others.

wrote on 10/26/2020 3:32 PM:
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?

Chris Esselstyn has converted a Schreder glider and an ASW 27 to twin jet self-launch. You can
probably find his contact info on the SSA website or the FAA aircraft registration lists. Both
have flown successfully at Parowan during the annual motorglider event there.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

I'd be curious to know which Jetcat models.

P120 and other brands through 320N. I think the starter motors are all brushed but the pumps are all brushless. My experience plus all others of my buddies is that turbines less than about 6 grand are expected to behave this way. So you bring a jet to fly and second one as a backup(essentially the same idea as a twin/redundant install). I can't speak for the class that are likely intended for large UAV in roughly the 10 to 20 grand range. I would expect better reliability out of those..

On 10/26/20 9:39 PM, Eric Greenwell wrote:
wrote on 10/26/2020 3:32 PM:
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?

Chris Esselstyn has converted a Schreder glider and an ASW 27 to twin
jet self-launch. You can probably find his contact info on the SSA
website or the FAA aircraft registration lists. Both have flown
successfully at Parowan during the annual motorglider event there.


Chris posted extensively to the earlier version of this thread,
9/17/2018 he talked about his uncontained Jet Cat rear turbine wheel
failure on his HP-18 conversion. Easy to find if you Google
rec.aviation.soaring.

That ship is Miss August 2021 if you have the new SSA calendar.

Dave

I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.

Interestingly, the P300 has a bit of a track record of catastrophic failure.. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.

On 10/27/20 10:41 AM, wrote:
I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.

Interestingly, the P300 has a bit of a track record of catastrophic failure. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.


There were a lot of jets on display at the 2018 SSA convention, here's a
1-26 side by side installation that had a really slick single lever
retraction mechanism (FB required):

https://www.facebook.com/AuxiliaryPo...1828046778122/

But as I've told Chris, I don't think the future of motorgliders is
jets, high fuel consumption, they're loud, and not all that reliable.
Flying with JS-1 and -3 sustainers, the reliability hasn't been that
great. Chris landed his HP-18 out from my home airport, ran out of fuel
after a self-launch and short self-retrieve. Might as well go with a
Silent 2 FES if you're happy with that type of range.

On Thursday, August 30, 2018 at 12:32:03 PM UTC-7, Tango Whisky wrote:
My name is Bert Willing, and your post was nonsense. I know quite a couple of jet owners, and they never had a problem of starting their engins attention altitude.
I know three jet owners and everyone has had/has a problem starting or developing thrust.

On Tuesday, October 27, 2020 at 9:41:31 AM UTC-7, wrote:
I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.

Interestingly, the P300 has a bit of a track record of catastrophic failure. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.

I think you are way off on the install, by a factor of 3 to 5, assuming the engines are retractable. Obviously, multiple installs on the same model glider would be less.

Tom

On Tuesday, October 27, 2020 at 5:47:32 PM UTC-7, 2G wrote:
On Tuesday, October 27, 2020 at 9:41:31 AM UTC-7, wrote:
I really like what Chris has done and have reached out to him. What's on my mind is two 40kg class engines. You would have 175lbs of thrust, and in the event of one failing, you still have an adequate sustainer. I'm estimating the system would be around $25,000 (15k for the engines and 10k for the install). Where I am guessing entirely is the cost of the install, and if there would be enough room for two of this size engine. Two P300s are 10.5" wide next to each other, while two 40kg motors would be 11.5". So it seems they would fit in a lot of cases.

Interestingly, the P300 has a bit of a track record of catastrophic failure. I'm sure there is an explanation out there as to why, but I followed many incident threads and I never found a definitive answer. There was speculation that the rotor sizing resulted in a resonant frequency that was causing stress on the bearings.
I think you are way off on the install, by a factor of 3 to 5, assuming the engines are retractable. Obviously, multiple installs on the same model glider would be less.

Tom

Oh wow.. so people are charging $30,000 - $50,000 to install the door and retraction system? Like the one Chris did or the 1-26 at the convention? Paying more for the retraction system than the glider itself seems off to me for some reason.