sieze2

I was flying my boomerang Nano with a Mk1 wren supersport yesterday. It was the 5th flight of the day and I was loviing it! That was until the turbine seemed to cut out with a real whine. After 11 seconds it seemed to spool back up, but by then I was committed to a landing. When I got to it it was happily idling. Subsequent power runs show it it running fine if a bit hot. After 40 seconds of full throttle it will hold at 752 degrees centigrade. 15 seconds of full throttle it will hold at about 730 degrees.

Did the EGT exceeded its temp limit and the turbine cut to idle ? It now sounds a bit different at half throttle. The bearings sound fine as its spooling down. I was running a Foreign object screen.

I did email wren a few months ago to check if it was ok it ran at 720 degrees. The reply I got was that it's fine, and not to mess with the ecu if it's delivering good power.

Should I send it back to wren for a strip down? I bought it second hand and it has supposedly only done 45 5 minute flights since its last check over at wren.

The video is below, and advice would be greatly appreciated, I know many on this forum have much more experience with turbines.

http://www.youtube.com/watch?v=zOs74...ature=youtu.be

Dr Honda

My Feedback: (4)

that physical sound wasn't the turbine spooling down... that sounded like a bearing that was skidding.

What oil are you using? I know I just tore down a 44 that ran just fine, but I found that the pre-load system had gotten stuck because of the crappy oil that the last owner was burning.

The other thing it could have been... if the turbine overheated, and the preload stuck... you could have rubbed the compressor wheel on the intake bell. You may want to take the front off the engine, and have a look.

basimpsn

My Feedback: (5)

Yep there was a high frequency pitch? seems like a brief lub line clogging to your bearing ,That could cause the high temp.

My opinion

sieze2

Humm I took a picture of the compressor, and it looks like it started rubbing (particularly the dark grey area at the back of the compressor?) I was running Castrol TTS at 4.2%. How much damage are we talking? Is it worth sending back to wren. Is it going to be more than £500 to fix do you think?

basimpsn

My Feedback: (5)

Try moving the compressor nut from side to side to see if it touch the compressor housing. Or remove the housing and wet sand it with 600

sieze2

There seems to be no lateral movement with the compressor nut. I did just notice a bump in the casing that was not there before:

basimpsn

My Feedback: (5)

Good catch (FOD) , you have two choice,(1) Remove the casing and get deeper in trouble, [X(] or send it back

P.S I wouldn't run this engine again until the FOD is removed.

sieze2

Ironically yesterday was the first time I ran with a Foreign object screen on the intake, so I fail to understand how something was sucked in. It must have been smaller than the mesh I guess. Is the turbine a write off? Is it worth sending to wren for a tear down? If the bearing has spun it would have damaged the bearing mount I guess. Has anyone had a similar repair bill ?

Wren Turbines USA

My Feedback: (39)

Sending it to Wren is your best choice. They will determine if it it cost effective for you to repair.

basimpsn

My Feedback: (5)

Could be a small piece of the compressor broken off who knows. I would remove the front compressor housing and get an idea of how bad is the damage. If piece of the compressor is broken off, then you could be looking at bearing replacement. As for (write off) not even close.

My Opinion.

George

My Feedback: (57)

Is it just me, or do the "leading edges" of that compressor look very ROUGH?

As already said, send it back and get a proper assessment.

Meesh

My Feedback: (135)

Very!!!!!!!!!

Dr Honda

My Feedback: (4)

I couldn't tell. I was thinking that it was just the way the camera flash was reflecting on the casting.

Regardless, it's not good, and the engine needs to be opened before it's run.

hooker53

My Feedback: (106)

That whine was Defiantly the front bearing you can bet the bank on that and that bump as you call it is inline with where the bearing is sitting inside. Were you running a FOD screen Sieze?

traxxasnut1

My Feedback: (13)

I have limited turbine experence, but I have to say that the compressor shows alot of wear, and does anyone else see the object on the leftside of the compressor that's pointing down and what looks like a hole in the front of the compressor by the blades.  This thing looks like it sucked up alot of dirt

Jonas Bergström

Hi

I have run my both Simjet (2300 and Nexus) with Castrol TTS and when my engine was in for service, the Swedish turbine doctor CS Turbine Service called me and asked me what type oil I use. He told me that the engine was very cloggy/sticky inside and he think that type of oil don't work so good in these type of engine. So I changed oil to an different brand that other use here in Sweden.
I have use Castrol TTS for many year in my DA and Zenoah engine with good result but not in my turbine any more.

//
Jonas

sieze2

OK The turbine just got striped down by Wren, and they say the compressor threw a blade. Apparently this is the first Super Sport they have seen that has thrown a blade (presumerably just a chunk of blade). It needs a new combustion chamber as well as compressor, along with 4 hrs labour is around £500 if nothing else is damaged. The bearings and exhaust turbine are fine thank goodness !

I know others were talking about fod, but it had two mesh screens, so I found it hard to believe it could have sucked something in.

basimpsn

My Feedback: (5)

Could be metal fatigue, but glad to see you getting it fix

BaldEagel

I thought Wren's came with a FOD screen attached? show us a picture of the size of mesh to the FOD screen you put on, I agree with the others that the casing looks as though its been pebble dashed, surprising how much damage can be caused by water being sucked in at high speed, let alone a solid foreign object, I had to replace the intake trumpets on a six cylinder mechanically fuel injected engine just by running for 15 laps in the rain without an air filter, they looked a little like the inside of your casing?

Mike

sieze2

OK annoyingly I got my newly rebuilt supersport fitted after a new combustion chamber and compressor , but now there seems to be a big problem! Namely big flames and it won't rev beyond 40k (at all). What can I do ? Is it not switching over to kerosene ? It seems stuck on the fuel ramp and won't rev (not to mention the flames!!!!)

[youtube]http://www.youtube.com/watch?v=39gND6xeh_o[/youtube]

fireblade5437

I would not keep running on gas only as no kero means no lube to bearings...!

I would swap gas valve with kero valve as you know the gas valve is working if this still shows problem I would monitor the output voltage from ECU for the kero valve.

Thats where I would start...

Alan

sieze2

I did see bubbles in the fuel line travel to the turbine (I did not prime it) .Also there was fuel coming out the turbine so I think fuel is going in and bearings should be fine?

basimpsn

My Feedback: (5)

Check and make sure your fuel line is not connected to the propane line .

sieze2

Ok will check in a few hours. But would it start on the button with them wired the opposite way round? You can hear the propane ignite at the start of the start sequence.

basimpsn

My Feedback: (5)

Yes it would.