APS/Ω Gas turbine bike build

[Mobacken Racing]

As stated earlier I´ve been filtering the oil through an automotive filter for a while to get rid of any small foam particles that might be stuck in the tank.



I have also been filtering the kerosene the same way, although the fuel pump has an intake screen that should take up most of any dirt in the system. After running the fuel pump at full speed for a couple of minutes I checked the pump screen and it was perfectly clean, so I think I am good to go.



I will keep checking the inline filters after every run to see if there is anything in them, in case something blocks up the safety systems will shut the engine down before any damage can be done to it so I am not concerned at all.

Cheers!
/Anders

[saltwheels262]

What about running the oil filter full time on the chassis ?

Bf

[Mobacken Racing]

What about running the oil filter full time on the chassis ?

Bf

A very good question, I had it installed before but decided to skip it since it is quite bulky and the oil don't get dirty the way an IC engine oil gets. I will see if I can fit the filter somehow inside the fairings, I kind of doubt it but who knows...

Cheers!
/Anders

[Mobacken Racing]

One of the few things left to do before the new JU-02 engine is ready to be mounted in a test stand is to secure the engine casing to the compressor cover, a job I had saved until last since it took a while to decide how to do it.



I drilled 18 5mm holes in the stainless casing, then I assembled the engine and continued drilling the holes into the cast compressor casing. I used a piece of tape on the drill to mark out the correct depth so I wouldn´t drill the holes through to the air passages.



Threading the holes for M6 screws.



With the holes treaded I assembled the engine with the cover screws in place, this will certainly do!



Cheers!
/Anders

[manta22]

Your new engine is taking shape nicely, Anders. You have put a lot of work into it!

A word of advice- drilling holes by hand to a limited depth is risky. Even with a tape marker on the drill to indicate the proper depth, it is hard to guarantee the limited depth using a hand drill. I'd recommend buying or borrowing an adjustable drill stop and a threaded drill such as in these photos. This type of aircraft drill is short and threaded 1/4-28 to screw into the drill stop. The stop housing is adjustable to limit the depth of the hole.

Regards, Neil  Tucson, AZ

[Mobacken Racing]

Your new engine is taking shape nicely, Anders. You have put a lot of work into it!

A word of advice- drilling holes by hand to a limited depth is risky. Even with a tape marker on the drill to indicate the proper depth, it is hard to guarantee the limited depth using a hand drill. I'd recommend buying or borrowing an adjustable drill stop and a threaded drill such as in these photos. This type of aircraft drill is short and threaded 1/4-28 to screw into the drill stop. The stop housing is adjustable to limit the depth of the hole.

Regards, Neil  Tucson, AZ

Hi Neil,

I very seldom drill "important" holes by hand but now I had to since the engine is too large in diameter to fit the rotary table for my mill.

That is a clever tool though, I´ll see if Ebay has one to offer me in case I run into a job like this again. Thanks!

/Anders

[4-barrel Mike]

I'm just a poor boy  and usually cut a piece of brake tubing the proper length and slip it over the drill bit.

Mike

[manta22]

Anders, Ebay is where to find them at a reasonable cost.

Mike, A piece of rubber tubing works just fine for drilling holes. A microstop drill stop is necessary when countersinking a panel for a rivet or screw. That requires a degree of precision.

Regards, Neil  Tucson, AZ

[4-barrel Mike]

Steel, Neil  not rubber.

Mike

[Mobacken Racing]

I found a little spare time to get some jobs done on the engine today. First off the jet nozzle was made, I turned a flange in the lathe and cut and rolled a jet nozzle in 1mm stainless. The angle of the picture fools the eye a bit, the nozzle looks straight but it really is tapered.



Here she is with her clothes on, the nozzle should get a much prettier color as soon as the engine is started.



Then I managed to find a suitable chunk of aluminum so I scrapped my earlier idea with a 3D printed bellmouth and decided to make one out of alloy instead.



Here it has got its inlet radius and v-band flange groove.



Milling the outside radius.



Olov lended me a v-band clamp so I had something so test fit it with, I haven´t cut the matching flange groove in the compressor cover yet so the bellmouth is just stacked on top of the cover in the picture.



Cheers!
/Anders

[manta22]

Steel, Neil  not rubber.

Mike

Yes, I know. The problem with steel is that it leaves marks on the panel.

Regards, Neil  Tucson, AZ

[Mobacken Racing]

I finished the bellmouth add-on tonight, the compressor cover was put in the lathe and a groove for the v-band clamp was cut. I also cut an aligning edge so the bellmouth will center perfectly every time.



A matching edge was then cut in the bellouth piece.



With that done I fit the two together and smoothed everything out with the shop air grinder and a soft sand paper disc until I couldn´t feel the edge any more.



Like a glove!



Next up is to take everything apart, clean it and drill all of the bolts and stuff for wire locking.



Cheers!
/Anders

[Mobacken Racing]

More assembly jobs done on JU-02.



I´ve drilled all of the engine cover bolt heads for wire locking, managed to break all but one of my 1.5mm drills during the process...



The scavenge line Loctited and wire locked.



Torquing the NGV bolts to 70Nm with blue loctite.



Here I am angle torquing the compressor nut, 130-145° is the recommended twist of the nut.



I am currently taking the last 0.1mm from the turbine housing to get the 0.6mm radial clearance John suggested.



I have ordered a set of fancy stainless flanged hex socket screws for the compressor cover and engine casing, looks much better than the ordinary allen screws.



Cheers!
/Anders

[Mobacken Racing]

By the way, Olov and I have started a facebook page for Mobacken Racing. Make sure to subscribe since we´ll be posting all kinds of jet related stuff there.

https://www.facebook.com/mobackenracing/

[Mobacken Racing]

While waiting for some parts for the turbofan build I continue with the JU-02 project, the time has come to construct the test rig!



This time I plan to use a load cell to measure the thrust correctly, the "frame tubes" onto which the engine will be clamped have a sliding fit in the test rig so they can transfer the thrust to the load cell.



Four engine mounts have been made from stainless angle iron and nylon feets have been milled that will sit on top of the frame tubes.



Time to weld the engine mounts in place!



I didn´t weld more than needed to avoid heat distortion of the engine cover.



The finished test rig (except for the load cell) with the engine cover fitted, I am planning to mount it to the large fan I will build a motorcycle dyno bench from later. It weighs close to a ton so the engine won´t move it.



Before calling it a night I wire locked the flame tube screws, no risk that they will fall out now.



Cheers!
/Anders