Turbotronic

Hi Gerald,
Actually your design after your trial and error is very good. Since we were looking for thrust in the region of your engine we needed to compare your real word data with the new design. The design we got from the student was for lower massflow but higher pressure. The new compressor has a smaller inducer but a larger outer dia of 75 vs the switzer you used. His tast was for 200N and high pressure for better SFC.
The graph is for static pressure which as you restrict the flow pressure is higher and massflow less (left of graph) however as you lessen the restriction the mass flow increase the static pressure decrease but the total pressure (which is the static plus dynamic pressure, like a pitot tube on an aircraft) increase. At some point the compressor for a given rpm can no longer pump more air through the system and the static pressure collapse. (choke, ie cannot increase air breathed)
This is not really meaningfull in this case as it is theoretical in this case, ie the combustor and turbine/nozzle is not accounted for.

So if you block the air completely there is only static and no dynamic and you have complete stall, which is something else.
For us experimenters we know when it happens.....
You sxxxt yourself.
Andre

athome

I've finished my turbine and my turbinestand! Also the gasadapter is finished now.

here a few Pictures

Regards Lukacs

athome

Hurrrraaaaahhhhhhhhh I did' it!!!!!!

absolut first start! Only with Gas because I didn't got my JET A1
But it works!!!!!!! Absolut amazing moment

[youtube]http://www.youtube.com/watch?v=OILbBIG3Cfo[/youtube]

next time with JET A1 and then.... the story goes on!

Best regards Lukacs

athome

Who has access to this Garret compressor preasure diagramm?
I couldn't find it on the garret honeywell website!
Regards Lukacs

athome

Dear Gerald

do you have your ECU settings for your GR130 available? Would be a great help
Thanks

regards Lukacs

Gerald Rutten

I have a different ECU than yours, I use FADEC from xicoy. You can simply start with a generic KJ66/P80/P120 like set-up which would be in your projet manual. If not, use following:

Idle rpm: 34.000
Max rpm: 126.000 (use 90.000 for initial tests and increase slowly when engine is happy)
Min egt/start egt 150c
Max egt 800c (for acceleration only, stop accelerating if max continious reaches 700 degrees and investigate. After tests and adjustments max temperature should be no higher than 680 degrees, ideal 650 degrees or cooler.)
fuel ramp slowest to start with, you may have to find your pump starting point which should be described in your ecu manual

Any other data, just ask but most is generic.

Rgds,
Gerald

athome

Thank you Gerald

Will try that. Got it one time to run but then it went off during accelaration at arround 7500 rpm (Temperatur was lower than 350°)
But now I don't get it to start with gas too....

Well I see... I have to go thorugh this...it was too easy before

Regards Lukacs

Gerald Rutten

Could you see any message on the ecu display? Maybe egt probe not good positioned, maybe too less exposure on which the ecu assumes flame-out and stops the start cycle. Sometimes rpm could be erratic due incorrect possition, did you see any rpm fluctuations not consistand with actual rpm?

Hope you get it running soon, once you lit the gas can it's an addiction.......

Rgds,
Gerald

athome

Hi Gerald
No no error everything OK so far. Tried several settings with the timing of the gasvalve and also with the speed of the startermotor...no success i can not ignite the gas with a cigarette lighter too during the short pause of the starter Motor (from behind)..


Strange thing, beacuse at the first start (which I've filmed) and 3 or 4 starts later it allways worked..but now I have no success..

today, i coud start with gas once, when i reduced the starter Speed to 1.5 Volt.

Looks like the gas is to fast out of the chamber.... (i have only one gasline next to the glowplug)

regards Lukacs

athome

Now I have completely disassembled my turbine...
But everything OK.... And I can without problem ignite the gas




But I think I've found the problem...... I measured the distance from the outer Gas-can to the cc and I think there is the problem. I can barely enough pull the glowplug coil so that it really reaches the cc!! And beacuse i've not soldered the glowplug mounting to the cc the coil gets cool down during the acceleration of the startermotor!!!! hope you can understand what I'm talking about


Regards Lukacs

Gerald Rutten

yes I understand. The coil does not have to reach the chamber but the distance between plug/boss and chamber should be zero, they must touch each other. Any air gap in between will result in false air getting through which can give variuous starting problems. Try to "dent" out the area where the plug or boss meets the chamber so that the chamber touches the plug or boss as tight as possible. This should help in lighting the gas. This is mainly the reason why some choose to solder the plug boss to the chamber which makes it air tight. In my case I make the boss long enough so that it touches the chamber firmly.

Another tip, see that the opening of the gas pipe is not too large, the chamber get's filled too quickly making gas/air mixture incorrect. Where do you inject the gas into your chamber? I have a seperate tube which projects into one of the sticks at the rear. Sometimes a second gas line on the oposite stick helps in beter ignition.

Rgds,
Gerald

Modified Wren '54 engine with dual gas starting pipes which improved reliable starting:

athome

Thank you Gerald

Wow how many turbines did you built?

I have only one gas pipe and the hole is exactly next to the line as you will see on the picture. But I have a small gap of 0.5mm in between of the cc and the plug/boss, so as I mentioned before, that is the Problem. Thank you for confirming!

I've found a longer glow plug (see the pic) and reassmbled the turbine and as soon as I pulled the coil arround 4mm (now it goes into the chamber) and entered a little higher voltage for the plug the turbine started again like a charm.

I have to fix this gap thing because I belive that the glowplug will oxidize/corrode after a few starts and that was the reason that it startet 5/6 times in the beginning without a problem.

What do you think about a kero start system? maybe that is the other option.

Regards Lukacs

athome

Hi all
bought a glowplug from Wren:


And now every gasstart is a success!

At the moment I'm debugging the acceleration! Still to low and really low temperature! I increased the Pump voltage and now I got it to run up to 20K but then went of saying "min. calibration RPM not reached"
During this acceleration I had only 400°C and excessive Fire! Maybe because of lot start failures or I have to change the Kittelberger injection ring (bended needles aginst airflow) to Geralds design!

Regards Lukacs

athome

HURRRAAAAAAAA!!!!!!!
HURRRAAAAAAAA!!!!!!!


[youtube]http://www.youtube.com/watch?v=keuy_H7Tw0o[/youtube]

It's running flawless!!! Only the parameters were the problems!!!!!

Amazing!!!! Unbelievable!!!!

Regards Lukacs


HURRRAAAAAAAA!!!!!!!
HURRRAAAAAAAA!!!!!!!

chrigui

great job...!!!

maybe rotor imbalance noise.....

Gerald Rutten

Very good, I can hear you having fun while the engine accelerates ha ha ha, it's addicting!!!

Indeed, there might be some imbalance, you need to check that before going to higher rpm. Also the stand does not seem to be supported very stable. Remember, this engine is capable of producing +130N at it's top rpm. I also use a remote stand and a simple trick before actualy starting the engine is to switch on the thrust indicator, grap the engine by it's mounting and than pull at least 120% of max rated, in this case you should read 150N (appr. 15kg) while the stand still holds.

Congrats on your first run!!!!

Now the real deal starts.

Best regards,
Gerald

chrigui

I can balance your engine...if you want..

athome

Thank you Guys
Absolut right! there is imbalance, that was the reason that I only went to 50K and not higher. Hey Chrigui thank you for your offer but I will go to Dieter Albisser, he lives close to me and he will do the fine balancing. But first I wanted to get started, not that I have to reassemble and the whole balancing was for nothing

Wow I'm really impressed

Regards Lukacs

chrigui

no problem... i can do this service for home builders also

athome

Right and good hint! the stand itself i've tested this way but not with the trestle... I was surprised that it worked flawless with the new Parameters!

regards Lukacs

athome

Hey Guys
would you first balance and then do further tests, or would you first disassemble and do a short check? How do you mark the wheel, compressor and the nut on the shaft?

Regards Lukacs

Gerald Rutten

Balance it anyway. The ghost you will be working on all the time during tests wil be egt, that will be the prime parameter to watch for subsequent runs. However, when rotor not in balance you will never know if any high egt's during testing is caused by imbalance or somethinh else.

I noticed on the movie however during start-up top side flame hot spot, maybe that side fuel needle is not properly positioned.

I mark my rotating parts simply by grinding a very small score in the piece with dremel cutting disc, any type of scratch will do, just do it gently.

Best regards,
Gerald

Here you can see some samples of position marks:

chrigui

P140RX balancing after bearing change

athome

Thank you Gerald for the hint!

Nice blancing Machine you have Chrigui Is it yours? not bad! quite expensive an original Schenck....

Best regards Lukacs

chrigui

yes...is mine...i buyed used 2 years ago for balancing and repair service