barger

Hi turbine newbie here just installed my new k100g in my jet legend viper almost ready to maiden but have noticed on the last few start ups the turbine takes longer to start and goes all the way up to 900c .Then i get a message high temp and then it quickly cools off to 600c and is then running.Is this normal or is something wrong. This is a brand new turbine i assume it is set up for diesel from the factory it seems to run okay .

fw190pilot

It is normal for temps during rampup to idle (slow rotor rpm) to be higher than a running turbine. Now that you have a few runs on the turbine the pump is probably starting to loosen up and pump fuel a little quicker now. You could try to reduce the fuel ramp value a number and see if that helps.

barger

Thank you for your suggestion,Mine is idling at 600c and i notice from you tube videos other k100g idle at 450c So if i reduce fuel ramp value that will affect idle temp as well.?

fw190pilot

No just the temp during the rampup phase to idle. What temp does it run at max rpm? If it is staying below max temp its ok might just need a minor adjustment to the position of the temp probe. I would contact Barry or Dirk and see what they say about it.

barger

I have not checked temp at full throttle because my wife has a bird everytime i start it in the garage and no asphalt outside but i will check full power temp in the morning after she goes to work...thank you for your help

cmp3cantrj

Since the turbine is starting slower it doesn't sound like the fuel ramp is what needs changing. Try reducing the pump start point by 2 (and repeat if it is still exceeding 700C on start) if you can't get the start temp below 700 then there is probably something wrong with the engine/fuel system.

600C is rather high for idle on this class of engine so it does sound to me like something bigger is wrong.


Possibilities are

Temperature probe in the wrong place.

kerostart burner valve is not closing properly.

internal leak in the fuel manifold (to check this run the engine in the dark and look back up the tailpipe (from a safe distance or use a mirror) to make sure combustion is evenly distributed.

Rotor not turning freely (to check this turn by hand if possible or check how long the rotor spins after you shut down.- if much less than 20 secs then there is probably a problem).

One other query. Has this happened SINCE you installed it in the model? (ie were your previous runs with lower temperatures all done on the bench?)

If so it could be the installation that is causing the problem.

Two possibilities are:

1. Not enough air getting to the engine (inlets obstructed)

2. Tailpipe too close to back of engine - there needs to be a gap. Check the correct gap with Kingtech or a rep - as the correct distance (or to be precise, where you measure it from) varies with tailpipe design.

barger

I almost feel that it is a false temp reading because the tailcone does not glow orange i seen a temp of 910c and it showed no visible signs or smells of extreme heat.If it is a false reading could that trick the ecu into a long start?

barger

It behaved this way on the bench also i did not catch it then because i am so new to turbines i thought these were normal temps.Also installed turbine proper distance from thrust tube 25mm for k100

gunradd

My Feedback: (9)

From what you are saying it sounds like a temp probe issue. I would not use this engine like it is and send it in for service. Please call Barry and talk to him about how to handle this.

barger

Already emailed kingtech waiting on reply.I just ran it twice for 5min each time.It was better it did not hang as long at 800c on start up.The longer i ran it the better the temps are.At final shutdown i was getting 536c at idle and 636c at full power 140,000rpm,idle at 43,000rpm(still getting high temp readout on initial start up.

Quandry

My recommendation is compare your settings on the turbine to the page in the manual which shows what the settings should be for Diesel. A friend and I bought two K100G's at the same time, both engines came with different settings, one of which was not starting correctly, we reset them as per the instruction manual and they start and run 100% perfect every time.

Don't let an assumption - ruin your fun!!

HTH

barger

Yes your right that is a possibility. ....I will dig into that tomorrow am.I will post what i find

cmp3cantrj

Those running temperatures are fine. I wonder if you did have a problem with a valve not bedded in properly. That is the only cause that is likely to clear itself.

If the start is the only time that the temperature is high you can usually clear it by reducing pump start point gradually.

barger

I am going to check start up parameters tomorrow morning just to make sure it was not set up for kero from factory if that is not it i will try your suggestion. .I would really like to solve it in house without pulling it out and sending it away.The temp did spike to 700c after it was running when i went to full power maybe twice then it seemed to get better it was also kind of missing or spitting when i advanced throttle early on then it cleared and ran better and cooler.

gsmarino2000

My Feedback: (2)

Greg,

Mine gets no where near those temps on start up. I would agree with thoughts on thermocouple location or calibration. Unfortunately it's internal on the K100G and so hard to check. BTW, mine have came from the factory set up for kero - you are supposed to make a few minor tweaks as shown in the manual.

Greg M

marquisvns

Here's the latest from Greg:

I am getting a high temp reading on start up i have seen 910c.and then hangs for a bit at 800c then quickly cools to 600c at idle . The longer i run it the better it gets.It still goes to 800 or 900c on start up but then i have been getting more like 636c at full power 140,000rpm and at idle i get 536c at 43000 rpm.This has been consistent the last two times i ran it. Can you help me with this?

marquisvns

I responded the following:

Those are good numbers. Upon fuel ramping, you could dial it down a bit, like a couple of notches on the second parameter under START menu.

Regards,
Barry

cmp3cantrj

A variation of around 100C depending on the exact position of the thermocouple is quite normal. Even if it protrudes exactly the right distance into the flow there is still a variation depending on the position around the circle. Every engine has a slightly different temperature distribution with hot and cold spots - this is impossible to prevent as the flow in the combustion chamber is necessarily turbulent. In addition please bear in mind that the ambient temperature affect the measured temperature. Every 1 degree rise in ambient will produce a 2 degree rise in EGT. Only a manufacturer or dealer will have enough experience to say with certainty what is within normal range for any particular design. However as a rule any temperature over 800C or idle above 600C indicates a problem that requires some adjustment. Having said that there are some designs (eg Hawk) where the thermocouple is in a completely different place and so all bets are off.

I would suggest advancing the throttle from idle in small steps. After each step wait fo 10 secs.then record temperature and rpm. At first the EGT should fall on each step. Later it will rise again. Make a note of the minimum temperature. This should be in the low 500's or lower. If that is the case then any remaining problem should be fixable by ECU adjustment.

barger

[QUOTE=Quandry;12090934]My recommendation is compare your settings on the turbine to the page in the manual which shows what the settings should be for Diesel. A friend and I bought two K100G's at the same time, both engines came with different settings, one of which was not starting correctly, we reset them as per the instruction manual and they start and run 100% perfect every time.

Don't let an assumption - ruin your fun!! Ok so Geoff gets credit for solving the first problem all settings were set for kero operation.I reset the parameters for diesel and start up much cleaner no popping or spitting.Top end of fuel ramp went to 920c with high temp displayed then cooled off to run at almost the same numbers maybe a touch warmer 540c at idle and 650c wot.Then i went with Barrys recommendation to lower the pump start ramp 2.No change high temp read out again on top of fuel ramp and running temps 536 540c idle.....636 650cwot.On the third run i lowered the pump start point from to+2 to auto +1 on cmp3 suggestion.And fuel ramp did not go above 750c with no high temp warning.So i think from What Barry and others are saying these are acceptable numbers.Its time to maiden this jet.I thank you all for your help and advice because you all know how important your first turbine model is emotinally and financialy.
Greg

barger

Okay sorry to be a pain but this hi temp thing keeps happening and its hanging at high temp 928cfor 30seconds maybe but i have a side question what kind of temps will the double wall tubes take before radiating out to the fuelsage.I have a couple quarter size lightly raised bubble on the underside of the fuse.I am not sure if this was heat induced or just a mould imperfection . Remember i am new to this and dont have alot of local guys to ask.I realize on startup the temp will spike in heat but to hang at those temps just does not seem right could i be damaging my fuse with high temp hanging?(running temps still the same)

gunradd

My Feedback: (9)

In my opinion your start settings are wrong. It should not be getting that hot. Are you getting flames on start up?

barger

No it never did have flames.I emailed Barry today and he promptly called me and we adjusted down the pump rate .It seems to start faster now and no high temp read out.I was concerned about the thrust tube temps but Barry explained these high temps are internal and cool significantly by the time they reach the thrust tube.Great service kingtech Barry did a great job in explaining turbine temps to me.

barger

Last update on this issue the turbine was sent back to kingteh and the temp probe was adjusted and is running normally again .Great service with these guys they stand behind what they sell.