APS/Ω Gas turbine bike build

[Dynoroom]

With the compressor cover properly adjusted for compressor clearance it was about time to get the turbine cover done as well. I painted the cover with scribing fluid to see where the blades rub.

I did aprox. 10 passes of painting, rubbing and grinding in the lathe before I was satisfied.

A bit difficult to take a picture of the result, but here it is. No rubbing whatsoever with the shaft pressed in every possible direction.



With that done I can start thinking about the combustor design, I measured everything and fitted a handful of evaporators just to get an idea of what everything will look like when finished.
Cheers!
/Anders

If this is the photo it's the turbine side. It is common to "clip" the turbine tips to create turbulent flow as it helps the exhaust exit faster and at a lower pressure. This is due to the rotational flow of the exhaust with no modification. 

[Mobacken Racing]

Anders,
Like many others, I am amazed at your abilities and capabilities but now have a question.
In the finished compressor clearancing photo, the leading edges of the vanes have been flattened off on the outer portion, resulting in a relatively sharp angle at the flat’s trailing edge.  It seems like that would lead to separated flow and affect the flow and efficiency.    Just wondering about why the flat is there.  Thanks.

Thanks!

I am not really sure what flat edge you are talking about, could you please do a quick photoshop arrow on the picture for me?

If this is the photo it's the turbine side. It is common to "clip" the turbine tips to create turbulent flow as it helps the exhaust exit faster and at a lower pressure. This is due to the rotational flow of the exhaust with no modification. 

A friend of mine is building a gas turbine with an even larger compressor wheel and the same turbine wheel, he has done some severe clipping of the turbine exducer to increase its flow capability.

The downside with this is that less power is extracted from the turbine wheel leading to increased exhaust temps since the engine needs to burn more fuel to keep up with the power requirement of the compressor wheel.

[Mobacken Racing]

https://youtu.be/MfO9PIuYw0E

Starts at 8:14, too bad they didn´t include any sound.

[Interested Observer]

Anders and Dyno,
Sorry, I missed the subtle changeover from compressor to turbine wheels.

[bbarn]

https://youtu.be/MfO9PIuYw0E

Starts at 8:14, too bad they didn´t include any sound.

Nice write-up Anders!!!

[Mobacken Racing]

Nice write-up Anders!!!

Actually I wasn´t involved at all, they emailed me a month ago and asked if it was ok to borrow some video clips for their youtube channel. They must have done some serious research to dig up some of those photos.

They did a good job of it, most "reporters" tend to live in a parallell universe and don´t really care about reality and such nonsense. They invent their own story that sounds more impressive/funny/whatever in their opinion.

[bbarn]

Nice write-up Anders!!!

Actually I wasn´t involved at all, they emailed me a month ago and asked if it was ok to borrow some video clips for their youtube channel. They must have done some serious research to dig up some of those photos.

They did a good job of it, most "reporters" tend to live in a parallell universe and don´t really care about reality and such nonsense. They invent their own story that sounds more impressive/funny/whatever in their opinion.

Ha! we've seen that too. They really did do a good job if they didn't interview you. Good reporting and fact finding on their part.

[Mobacken Racing]

I have cut out the sheet metal parts for the combustor now.



I had a cosy Friday with the family in the tv sofa, while the kids watched the Bumbi Bears I marked the combustor liners for hole punching.



I made a hole punch a couple of months ago with this project in mind. Two thick Hardox plates were given a 1.5mm gap and welded together, then I drilled a number of different sized holes and cut down worn out drills into punches. It works perfectly as you can see!



Cheers!
/Anders

[manta22]

Anders, I like your idea for a hole punch- very clever.

Regards, Neil  Tucson, AZ

[Seldom Seen Slim]

And the family scene is so touching, so hot rodder -- Mom and the kids watching TV while Dad, sitting right next to them, works on designing and building his freakin' jet turbine engine.

Just like in almost every house.

[manta22]

Jon;

It should be on a Currier & Ives Christmas card!

Regards, Neil  Tucson, AZ

[Mobacken Racing]

Thanks Neil, it works great! Just to test the jig I just now went outside to punch the 5mm row of holes.

I wish I had this punch when I made the combustor for JU-01, easiest job so far on the engine build.



Jon: Our beloved daughters are used to pretty much everything by now having been around guns, gas turbines and motorcycles since they were born. Sure beats being brought up in town playing Pokemon all day long.

[Mobacken Racing]

I punched out the rest of the holes in the outer liner today, the tool is very useful for making larger holes but the <4mm holes are easier to drill.



I can´t thank my father and his/my friend Micke enough for letting me borrow their slip roll, it sure makes these jobs easy compared to hand rolling over a steel pipe like I did before.



One piece done, four left to do. Some of the holes will be countersunk/angled later to induce swirl in the primary zone.



Cheers!
/Anders

[Mobacken Racing]

More work on the flame tube. First out was to roll and weld the transition cone between the outer liner and the NGV wall.

Since all of you know the difference between the primary and teritary zone hole diameters you can tell from the picture that I f*cked this one up, I welded the cone to the wrong end of the liner!



Oh well, cut it away with the angle grinder and weld it to the other side. Here I´ve just spot welded the cone and the short strip that will be drilled for the securing screws later.



Success, it was possible to remove it afterwards!



Time to start with the inner liner, after cutting out the sheet metal I did the hole marking in the livingroom sofa with a cup of tea. Much cosier than sitting in 10°C among the workshop chaos.



Drill drill!



After rolling and welding the inner liner it looked like this.



Evaporators test fitted.



And finally a pic with the outer liner in place, all that is missing now is the front wall.



Cheers!
/Anders

[Mobacken Racing]

It was about time to put the lid on the combustor. To make it less prone to warping and to make some room for the oil lines I decided to make it an inverted dome with the bulge inwards.

But, how can I do that without any proper sheet metal tools? I just have to make a tool of my own then, so I threw together a sledgehammer operated poor mans Pullmax.



It worked just fine, the stainless sheet warped a little but that is easily straightened out when it is being welded.



The finished lid, this will do just fine.



Tig welding selfie time!



I won´t weld it more than this until I am absolutely sure that I don´t have to modify anything.



Test fitted inside the engine, I see that I need to make a minor adjustment where the oil return line is (on top in the picture) since it just barely touches the combustor lid now.



Merry Christmas to you all!
/Anders