barron06

Hello, I have a Kingtech 102G4 that has been running consistently since new (Nov 2022) but I always noticed more (shut down) smoke comes up than I'm used to seeing in my other turbines. I decided not to touch it because, well, it's running. Besides, I'm not well versed in making adjustments. I know what the book says about the settings, but it's really not enough.

My main issue is, since transitioning to summer months (Temps 95, at sea level and using Jet-A), I notice popping that occurs during power reductions while flying... such as preparing to landing or going into the downline of a loop. No flame outs, but I am concerned. It did not do this during the winter/spring. I don't know if summer months is a factor or just a coincidence.

UPDATE: I am now consistently getting flameouts on hard acceleration from idle. Error "Low Speed".
- Cleaned fuel filter (No Algae or junk but back flushed anyway).
- No kinks in fuel line
- No bubbles in fuel line. Even when checking while accelerating
- Did a Tx learn
- Does not occur with a ~5 sec acceleration or from a hard accel from, say, 40% power.
- Nothing has changed. 805 min, KT Oil, Jet-A, Sea level, 95 deg, high humidity.

My settings (from factory):
PW - 740 Max set, 610 max running
Accel delay - 010
Decel delay - 012

Log file:
In flight log.. 1st failure. This was when I had auto restart set. "Low Speed" error flashes quickly at 1:16. Disregard wonky throttle at 1:06 (I was moving throttle searching for my 1/4 throttle tx beep).

Bench run - No "Low Speed" error but it does show in summary on terminal. I was doing a RC learn, hence the throttle steps.

Pic of "Low Speed" error


Manual says it could be a wonky RPM sensor but Im not sure.

Thanks in advance for any help. - Barron

jackdiazccs

As temperature and humidity increases, the amount of oxygen molecules per volume of air decreases. As a consequence, the fuel to oxygen ratio might shift to a critical or sometimes impossible value to maintain combustion. It is a design / tolerances issue.
The effect of increasing temperature and humidity is equivalent to increasing the altitude ("density altitude"). There are tables to easily calculate it.
There isn't much to do, besides proper adjustment of max pump pw, and acceleration / deceleration delay.
I have had turbines that only work properly before 11am

Jack

barron06

Thanks for your input. Having received your input decided to try some changes. I increased accel and decel delay to 10-12 and 12-14 respectively. Under similar ambient conditions, the turbine stopped flaming out on the ground as before. Also, the popping sounds I was hearing while reducing throttle were mostly reduced in flight, but still there...most notably on the ground. After 8 flights, I considered increasing the the settings further but chickened out. I figure may not see anymore 95deg days ~2700 ft density alt numbers since summer is almost over.
Question: Am I correct in thinking that increasing Decel delay will reduce popping on deceleration or was it me increasing Accel delay?

Thanks,
Brian

jackdiazccs

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jackdiazccs

Glad the acceleration issue is solved.
Yes, increasing the Dec delay may help with the popping while decelerating. Acceleration delay has no influence in the deceleration.
Both values can be increased as long as you feel comfortable flying.

Adjusting max pump pw is very important also. It should be set at 15 or 20% above the pump pw read at max rpm. As I understand, the "unit" of voltage change that the ECU uses to command the pump is a percentage of the max pump pw. The larger the max pump pw, the bigger the minimum voltage change is. That can easily flood the engine in a critical stage. I have fixed many start issues just by adjusting that max value.

Jack

barron06

Jack, Thanks for your input. Concerning the pump pw setting I had heard of the +15-20% setting. Your last response now tells me why. Hopefully this post helps someone else by preventing them from sending their turbine in for what seemed to be a failed rpm sensor (if you go by the manual).