Tip22v

I forgot to mention the reason for the afore-mentioned fires at start-up. When I mounted the turbine in the habu I mounted it from the bottom of the airframe, when I turned the aircraft over to start it the turbine was actually upside down. I now have personal experience as to why you don't try and start these turbines with the glow plug on the bottom. Now that I have the turbine mounting orientation correct she starts right up, in the jet, with no issues.

tow

That`s funny, my experience is quite the opposite. I found that mounting the turbine glowplug down actually made it ignite and start easier. This in a way it makes perfectly sense as gas is heavier than air and therefor will go "down" to the plug. Are you sure there is not another reason for your trouble? Anyway, what works will work :-)

Tip22v

I don't understand it either, I thought the same thing about the propane being heavier than air, but I've had a mis-start almost everytime I've tried to start this guy upside down, I've had two perfect starts in a row since I mounted it right side up (plus the 10+ perfect starts on the test stand). I'm going to do a couple more starts this week to confirm.

Tip22v

So I attempted a couple more starts. Turbine ignites the propane and then nothing. I tried three times it failed to start all three times. Seems like there is no kero getting pumped in the start process. I then hit the pump with a quick direct voltage to make sure it was free and turning, it was. I'm about ready to give up on this little guy. Any ideas? Thanks, Tom.

tow

During startup, what do GSU read, - RPM, PW? If pw number goes up the pump is running, this you also check (feel) by placing a finger on the pump housing if possible. Batteries are good I take it? There also is a possibility of a clogged injector-needle, in wich case returning to Lambert for repair is only solution I`m afraid.

Tip22v

Bobneal1

My Feedback: (21)

Tip22v

Thanks, I'll give that a try.

i3dm

My Feedback: (51)

Hello Kolibri users,

just to put it out there that if anybody wants a Micro LCD display for turbine data, or a telemetry adapter for turbine data for Kolibri and Futaba or FrSky radios, i make some cool stuff for the Kolibri.
There is even a Bluetooth data terminal (GSU) for android phones available
PM me if you like something.
thanks for reading.

Tip22v

Looking for some input here. I pulled the turbine from the jet and it started right up on the test stand, so there is obviously nothing wrong with the turbine itself. Here is my theory on the problem: The Habu32 has two elevator servos positioned on both sides of the turbine in close proximity to where the turbine RPM sensor is located. Does anyone know if the T35 uses a magnetic sensor for RPM data? If so, is it possible that the magnets in the servo motors are causing interference with the RPM sensor in the turbine? I suppose one way to test this theory is to pull the elevator servos and see if it starts as reliably in the jet as it does on the test stand...I'm also going to start video taping the GSU during the start sequence so I can go back and review the status messages during the start, which might also provide some more clues. Thanks for the help! - Tom

Tip22v

I bought one of these Kolibri units from Loir, works great!

Tip22v

Documenting here in case anyone has similar issue in the future.

I've tested my theory on the servo magnets being the problem and have pretty much ruled it out. I was able to use a more powerful magnet to cause interference with the rpm sensor, but I was not able to get any servo to interfere with the rpm sensor.

Based on information in this thread I tinkered around with the propane flow, reducing it with an inline valve. Because the turbine is mounted inside an enclosed space when the propane would initially flow and ignite it would cause a scary "pop", I believe that "pop" was having some kind of impact on the start sequence. I was able to reduce the "pop" by reducing the amount of propane flow with an inline restrictor valve, I further eliminated the "pop" by using my blower to very gently blow air into the intake of the jet during the first part of the start sequence. This resulted in completely "pop" free starts and the turbine starts much more reliably now when mounted in the jet (I've never had a problem with starts on the test stand, only when mounted in the jet have I had issues). I'll be doing more starts over the next couple of weeks to verify my findings.

c_makhija

c_makhija

Tip22v

Thanks for the info, I have definitely found the propane restrictor valve to be very helpful and I've been turning off the propane at 50k so it sounds like I'm doing that correct. I've done a few more starts over the past week and it's starting every time now so I'm hoping I've got it sorted out. I never thought about the liquid state of propane in the bottom of the tank (thanks for the heads-up), but I always leave my tank sitting right side up so that has not been a problem.

Thanks again for the help! -Tom

Mach1

My Feedback: (5)

I am having similar problems with my T-35. The engine has been flawless for 60+ flights. It always starts easily and has run great since new.
I was getting it ready for flying season this year but could not get it to start. (Nothing has changed since being flown 3 or so months ago). It will light off on propane and spool up to 26k but the pump never comes on to further the ramp. I then tried the prime procedure but the pump does not respond. I removed the pump from the plane and hooked it up to a spare fuel tank and used a 2S directly connected. Pump ran great. Very smooth no bubbles. Battery is good and charged. Any ideas?

Bobneal1

My Feedback: (21)

Install the pump and try it again. The pumps turn so slowly on start that if they sit for a while they will not push enough kero to get a good fuel ramp. If I let mine sit for more than a few months it won’t start. I have a wiring harness made where I use 1 cell of an LIFE battery through the balance lead to plug in to the pump with it still installed in the airplane.Run it for a few seconds to free it , with the fuel valve closed of course. It works every time.

scoeroo

My Feedback: (9)

We hope its just a case of sticky pump
Also check that the drive dog is releasing and not staying engaged holding the engin back in ramp up
I have the T25 , nice little turbine

Mach1

My Feedback: (5)

Thanks for the reply. I plumbed the pump in a loop through an off board fuel tank with fuel and the pump runs as normal from 8v down to 1.5 v (as low as I could go). Problem is it won't run when hooked to the ecu. When initiating the "prime function" (trim up, stick up, wait 5 sec) nothing happens.
Here is the really strange thing...With the onboard 2s connected to the ecu ( using the supplied connector, where the 2 inter pins (ecu batt in). If I measure the voltage of the two outer pins, where the pump connects, it reads 8.06v. You would think it would read 0v until the ecu commands voltage to the pump. Then, if I hook the pump to this connector, still powered up and measuring the 8.06 batt voltage, the pump will not run! How can that be!

Bobneal1

My Feedback: (21)

[QUOTE=Mach1;12671247]Thanks for the reply. I plumbed the pump in a loop through an off board fuel tank with fuel and the pump runs as normal from 8v down to 1.5 v (as low as I could go). Problem is it won't run when hooked to the ecu. When initiating the "prime function" (trim up, stick up, wait 5 sec) nothing happens.
Here is the really strange thing...With the onboard 2s connected to the ecu ( using the supplied connector, where the 2 inter pins (ecu batt in). If I measure the voltage of the two outer pins, where the pump connects, it reads 8.06v. You would think it would read 0v until the ecu commands voltage to the pump. Then, if I hook the pump to this connector, still powered up and measuring the 8.06 batt voltage, the pump will not run! How can that be![/QUOTE

You must have a break in the connection between the ecu and the pump . Maybe a break in the wire or a bad connector. If you load the circuit where you are measuring the voltage, the voltage will probably drop to zero.

My pump has bare Solder connections on the pump motor terminals . Measure the voltage at the terminals when the ecu is doing a prime or a start

Mach1

My Feedback: (5)

Yes, that is what I was planning on trying this morning. I was stunned when I read that voltage at the connector but the the pump would not run connected there. The way the main connector is designed, 6 separated pins, it hard to imagine a short and I could not detect one with meter (between pins). I can only conclude the short is in the ecu side??

Mach1

My Feedback: (5)

So, I powered everything up and measured voltage at the pump terminals. 0.00 volts. I metered the pump and power pins on the ecu. The positive 3 pins are shorted together (2 for power 1 for pump).
The 3 negative pins are not shorted together.

Mach1

My Feedback: (5)

I wonder, will the ECU direct the pump to run if there is a malfunction with the fuel solenoid valve i.e. the fuel valve is bad?

Bobneal1

My Feedback: (21)

Ohm out the wires from the ECU connector to the pump with the connector disconnected from the ECU. You could check across the pins on the connector that plugs into the ECU and I think it will read open circuit. Find the defect in the cable and your problem will be solved . Mine has a red 2 conductor JST connector between the pump and the ECU as well as a green MPX connector that plugs into the ECU.

Mach1

My Feedback: (5)

Hi Bob.
Yes my connector is the same, mpx to ecu, male jst to battery, female jst to pump. I checked the connector wiring very carefully. It ohmed out good.
I even made a new connector. Same results.
Because the pump will not run connected to the ecu when performing the "prime function" , I have to think it's the ecu itself. Thanks for you insight.
Much appreciated.