Turboshaft?

[elventu]

Today I made the coupling between the 12V motor and the oil pump.
Started from a piece of aluminum and a piece of 39NiCrMo3 steel, work done on the the lathe at job, and after I do the milling work at home.
I decided to couple the shafts using the left handed M8 thread on the motor shaft to transmit the torque, because I found the left handed tap at job.
It seems to work well, no noise coming from the coupling.
However, I think I have to reduce motor speed.
Without any pressure (just a bit of oil in the pump) it draw about 12A from the battery.

[elventu]

Today I milled out from a 5mm thick stainless scrap the lower flange for the combustion chamber and I worked on the conical pipe to match the measurements I need and to have a flat point for welding the cone at the flange.
In next days I need to weld them together.
Since at work we have a MIG welder dedicated to stainless steel, I decided to abandon the idea of using the TIG they also have, that comes from the previous factory there was in our shed (my employer bought all that things as a stock after the previous factory failed, but they never used the TIG in 20years, there's no argon bottle, no tungsten and the welder is covered by dust...).

I hope I can weld with the MIG without piercing holes in the 1.5mm flame tube...😂😂

[elventu]

Some other parts I made in this days.
I welded the top flange on the cap of the combustion chamber and I worked to match the other two flanges that hold the evaporator for the LPG.

In next days I have to finish the other side of the stainless flange in the photo and made the other one to hold the inner tube of the evaporator.

[elventu]

Today I made the flange for the inner evaporator tube and I finished the flange for the outer one.
I decided to make the LPG inlet with a 2mm drill, maybe this help me to have some backpressure in the LPG pipe between the needle valve and the inlet, to keep it in liquid state until it reach the evaporator.

Making all these parts with my mill is just a little more difficult than using a lathe...but I prefeer to avoid using the lathe at job, I don't want to abuse of the chance of using it sometime.
In next days I have to weld the tubes on the flanges, then I start working on the flame tube and on the combustion chamber.

[elventu]

Today I welded and adjusted some parts.
The evaporator tubes on their flanges (I can weld and adjust them rotating in 0.5 mm off center from the flanfe to the tube end, it seems to be OK for the job they have to do) and the combustion chamber base flange to the conical part between the flame tube and the compressor inlet, 0.2mm distortion on the flange, I think with 12 screws it can return flat when bolted in place!

In next days I have to make the turbine inlet square.
I cut the lower part of the conical reduction in order to have the same perimeter lenght of the square hole of the flange.
It have to be a simple work.
After that I have to cut to lenght the combustion chamber tube and the liner.
So far so good.

[elventu]

In this week I haven't a lot of spare time to dedicate to the engine.
However, I checked if the evaporator tube welding are sealed (at now I don't made the gas outlet holes, I have to check for their right position when I close the combustion chamber) and they isn't, then yesterday I re-welded and re-machined it.
Today I made the liner cap holes on the commercial cap I bought in january, after some P.M. with John (thanks a lot for the suggestions) I made 45x 2mm diameter holes, 10%of the primary holes area, on on the cap.
I used a lathe center drill for the job, to make an easier work and to make some countersink to help the air flowing in them.
Yesterday I also welded the turbine inlet flange on the conical reduction between it and the flame tube.
It seems that I'm not the best welder on the market...
I was used to weld with a different gas and machinery, the weld are ugly...
Nothing some work with the grinder with a flap disk can't fix, but I'm not so happy with them.
For the flame tube I want to find a different solution, maybe I can find a guy with a TIG welder here, to do the job properly. 😉

[elventu]

Today I welded the combustion chamber and cut the flame tube at the right lenght.
In next days I start to do some holes 😉

[elventu]

It is starting to take shape 😁
I secured the flame tube to the other parts with some welding spots to see if it is concentric with the evaporator, and I found a position in wich it is almost perfect.
Then I can't wait to see how it fit on the turbocharger!

[elventu]

In last months, I sharded this build on another forum, based here, in Italy, talking about cars mechanic.
One of the readers, an electronic expert, offered me the possibility to build a speed regulator for the oil pump (to save some Watts from the battery) that is based on the oil pressure.
This is a good goal for me, since I'm not good with electronics 😊

[elventu]

Yesterday I have the combustion chamber TIG welded by a factory near home.
I decided to ask them to avoid making a shitty work with the MIG at my job.
Today I started making the air inlet.
Some scrap 1-1/2" (48.3mm) tube, a curve and some 3mm plate.
Welding with my rugged MMA welder on mild steel is a lot simple than welding on stainless with the wrong equipment 😂😂

In next days I have to open the air passage on the combustion chamber and weld on it the air inlet, obviously after cleaning the inside of the diffuser I made today.

The project seems to come together nicely! 😊

[Johansson]

Nice work! I am not very good at commenting but I follow this with interest!

[elventu]

Mar 2, 2019 15:49:08 GMT -5 Johansson said:

Nice work! I am not very good at commenting but I follow this with interest!

Thank you Anders!
It has nothing to do with your ones, but I try to make it better as I can! 😋

[elventu]

Today I welded the combustion chamber inlet.
Tomorrow I have to grind some burrs, but the work is looking fine to me!
And there is, as planned, the space for the frame tube passing inside the pipe curve route.

[elventu]

3 hours of work, and the welds are smoothened, burrs removed and the flame tube is ready.
Fortunately I have some short drills I recovered where I worked, when a normal lenght drill after some grinding becomes too short it becomes less productive in the factory because of the "core" became bigger, but it was good for DIY works...
The shorter the drill, the more stable is drilling in small thickness material, so the holes are round as I want! 😉
I locked the flame tube on the chuck simply using an Allen screw with a nut (and some washers) centered in the evaporator hole and tightened, clamping the screw head in the chuck to allow them rotating together.
I supported the tube for drilling with a steel block between the tube and the table, and laterally I put another couple of scrap raw parts, clamped on the table to keep the tube from moving laterally.
A crude system but it does the job properly!



Tomorrow if I feel alive after physiotheraphy I want to do the gas holes on the evaporator.

[elventu]

Today I drilled the hole for the spark plug.
I have its "support" part made over ten years ago for the HX60 project...
I put it about halfway between the primary and secondary holes, it seems a right place to me, hope I'm right.
For the moment I decided to use a modified spark plug I machined to expose the central insulator and the electrode, I want to position it to use the flame tube as ground electrode, welding the support at the right distance to achieve a 6/7mm spark.
I drilled a 6.7mm hole for the insulator in the flame tube.
If needed I can enlarge it and machine another spark plug to reduce the threaded diameter to 12.5mm (to avoid damage to the thread if exposed to combustion), making the metal of the plug protruding in the chamber to give it more toughness.
My fear is that the expansion/movement of the flame tube can break the insulator if I let it to enter the tube alone from a small hole.

Someone have suggestions about what to do?

Thanks!
Davide