Holset HX50 Supermoto Jetbike

[slittlewing]

Hi All,

Firstly happy Christmas, hope everyone had a good one!!

I refitted the compressor housing (tube not welded in yet) so I could make progress on the engine mods and refit.

I tacked the new top cap onto the outer combustor casing and trial fitted int he bike, got the angle right on the 3rd attempt after tweaking a degree or two!

I was dreading the reconnection of the afterburner. I thought I would need to put an extension piece in at an angle and square it up (with the new turbo missing 25mm or so of housing due to the lack of wastegate).

A colleague at work kindly machined my laser cut new 10mm stainless AB flange with a chamfer and internal diameter for a close fit to the tubing.

After cutting the old flange off and trial fitting, the AB tube fits nicely without any additional spacer which feels like a great luck!!
















american football poems that rhyme

I have removed the engine and Tig welded the new 12mm top cap on fully.
There is some minor bevelling after the welding of the transition, but I think it’s probably OK to try as is?

Next jobs - sort out the new compressor connection and 10AN short oil drain.

Cheers

Scott

[wannabebuilderuk]

Looks great Scott, you'll be up and running in no time!

Quick question, what tig welder do you have? I'm looking to get one and so far am liking the look of the Stahlwerk tig 200 pulse st.

www.stahlwerk-schweissgeraete.de/DC-TIG-200-PULSE-ST

[slittlewing]

I went for a Sherman 206p, which is AC/DC 200A, IGBT. The reason being that according to a lengthy thread on a mig welding forum, it’s the exact same as a £1500 Jasic machine. Both are made in China (all of them are incl stahlwerk) but the Sherman doesn’t carry the posh badge.

www.mig-welding.co.uk/forum/threads/sherman-tig-jasic-in-disguise.93719/

A friend has a stahlwerk and is happy with it, they are similar price and carry a long guarantee if you buy direct.

You also need to budget for £200 gas setup/rental, regulator, rods, torch cups etc... it’s expensive to get going but I now wish I had one when I started the project!!
Cheers
Scott

[wannabebuilderuk]

Yea expensive with consumables however I'd only be doing small things so those 220L bottles should last me a while.
www.ebay.co.uk/itm/172298603673

I was tempted to get an ac/dc setup for future proofing but I don't usually use aluminium and harder to learn so simpler to go dc and find someone with the setup and skill to do it for me ha.

Plus it's a massive saving and still get a pulsed tig with pedal for £350 including shipping. Seems that sherman doesn't exist anymore but thanks anyway.

[slittlewing]

 They certainly still exist, check out weldes.de or tecweld.pl if you fancy a gander!

So the last couple of days have been very busy in the garage despite temperatures of 2-->6 degC! 

First nasty job.. despite trying to gain clearance from moving the turbo 4mm rearward on the topcap (making the transition more complicated), it was evident in the pre-fits that the compressor silicone hose would still foul the frame. So no choice but to "make more clearance"...









Next was fitting swaged connections for the silicone hose (compressor to combustor). I opted for an 8mm gap between, which I thought I had seen on here somewhere before or maybe just made up - not sure which!! I used a 3D printed jig to get the alignment and marking up:








Then was the spark plug. In my summer attempts to get it started on kero, I had moved the plug to near where the kero impinges on the flame tube wall (a little beyond in fact). But I had no spark plug boss at the time, so just threaded it into the 3mm combustor wall. My friend who turned the AB flange chamfer also made me a boss for the plug. However, with the top cap having billowed due to heat, the spark plug hole in the flame tube was no longer aligned with that in the combustor wall. I had to weld a patch over the original hole and make a jig to drill a new one, that would be perfectly in line with the hole in the outer wall. Then rethread in the flame tube. 










In this photo you can just about make out a 2mm gap between the boss (combustor wall) and FT. The spark plug thread goes through both.



Next job, completing the new 10AN Oil Drain to the tank. Again, 3D printed "shaft" used to connect the two fittings with a gap, in alignment:












And finally a pre-fit in the frame, alignment all looking good:












Next job is to repaint the combustor/oil tank and finish the frame patch. I have a larger burner nozzle on order, I will be moving from 13.50GPH to 17.50GPH which should get me to 2.7bar P2 or maybe a little more if the new turbo is on a more efficient part of the map (fingers crossed!)

Thankfully, the "mk3" engine looks to be more or less complete anyway!

Cheers

Scott

[wannabebuilderuk]

I'm getting envious of that 3d printer Scott, seems extremely helpful!

Out of interest have you tried combining it with photogrammetry/laser scanning of items so you can model the solution to the exact shape instead of the "ideal" shape?

Like imagine this - say you did the spark plug drill jig based of the c/c being perfectly round but it perhaps turns out to be slightly oval or the area you need to place the jig has something causing it to not sit properly to the curvature of the c/c - you'd scan the area then work off that surface to make the model that will be printed properly match the shape, If that makes sense lol

[Toni]

Hi Scott

When you test 17,5 gph nozzle, if it is too big, is there too much egt or boost?

Best regards
Toni

[racket]

Hi Toni

If a fuel nozzle is "oversized" , we simply need to reduce the supply pressure feeding it so as to not overspeed or overtemperature the engine , the reduced supply pressure reduces the flow through the nozzle to the desired amount , the only drawback with running an oversized fuel nozzle is poorer atomisation of the fuel and potentially poorer combustion efficiency ( smoking) , ideally we want to run max available fuel pressure at max engine power output

Cheers
John

[Colin Heath]

Been Busy

Looking real good and look forward to seeing the next run.

[slittlewing]

Thanks gents!!!

Ben - for the jig parts, scanning gives me no advantage other than slowing it down. I can cad a jig in 10 mins that will fit because the engine is made of standard simple “squares and circles” essentially. But for making bodywork for example, that’s where it would be handy! I have an Xbox Kinect camera that I might be able to use for that in future projects. Also, the PLA is flexible enough to take up a millimetre of curvature here or there.

Toni - As John says, with the bigger nozzle it will just be about slowly throttling upto the safe maximum boost based on TOT - or at least that’s the plan.

Cheers
Scott

[wannabebuilderuk]

Dec 31, 2020 15:34:53 GMT -5 slittlewing said:

Thanks gents!!!

Ben - for the jig parts, scanning gives me no advantage other than slowing it down. I can cad a jig in 10 mins that will fit because the engine is made of standard simple “squares and circles” essentially. But for making bodywork for example, that’s where it would be handy! I have an Xbox Kinect camera that I might be able to use for that in future projects. Also, the PLA is flexible enough to take up a millimetre of curvature here or there.

Toni - As John says, with the bigger nozzle it will just be about slowly throttling upto the safe maximum boost based on TOT - or at least that’s the plan.

Cheers
Scott

Yea that's handy making everything simple shapes, there's should be plenty of resources out there for kinect to 3d model though your best bet might be photogrammetry which can be done with any modern phone.

[slittlewing]

Hi All,

A further update - the impingement starting pipe has been welded in (by a professional fabby, I didn't trust my skills on that one) and the small drill bit gouge mark also welded over






The 17.50 burner nozzle also arrived and is fitted. I cleaned up the combustor flanges and copper gasket. Previously I had also used some loctite instant gasket in addition, but this had gone black and burnt on disassembly so I will try without this time. 






I repainted the engine and it now looks a little bit more respectable. Also, the 10AN (very short!!) oil drain pipe is finished, with pretty minimal clearance to the compressor hose! Its a little tight getting it all together but it does fit.





I wanted to weld a 25mm extension piece onto the turbo inlet, for mounting the air filter (kitchen sieve) but after trialling a printed piece, the engine would not go into the frame with this. I have an alternative idea that should work instead.



The compressor hose clearance I had to make in the frame is also now fully welded and painted over. It pained me to ruin the powdercoat, but its not that visible and it was unavoidable!



I am waiting for some new silicone hose clamps to arrive next week and hopefully the mk3 engine can finally be fitted and the bike put back together. 
There are a few more modifications I am thinking of making:
-Moving the spark plug in the afterburner round 30 degrees or so for clearance to rear mudguard (new boss to be welded in). This would also allow me to fit a straight plug cap instead of the current 90, which got hot during afterburn. 
-Gauze filter will be fitted on oil pump suction line to avoid metallic debris blocking the pump rotors, which is clearly what happened previously when the turbo failed.
-New bronze pump rotors on order to replace damaged ones from said debris!
-Possible addition of a ball valve between fuel tank and pumps to save my garage floor from puddles...
-New ECU developments coming...!

I also have a new main oil filter coming and will flush the system before hooking up to the turbo with 0w30 oil this time.

Cheers

Scott

[slittlewing]

Well the silicone hose clamps arrived, I went for “Norma” ones instead of the Mikalor I had used before. After some head scratching and a tight squeeze, the engine is in the bike!
Silicone Hose and v band clamp arrangement being so close to the oil drain was very tight but it fits (more luck than judgement)! Wish I had given myself another 20mm clearance when I made the frame cross bar but that’s hindsight.

I hope the silicone hose doesn’t fail because it’s engine out to replace!






Parts on order to complete the mechanical installation.
Cheers
Scott

[racket]

Hi Scott

LOL.......yep , hindsight is a wonderful thing , somehow it only seems to rear its ugly head at the end of a build .

All looking good though , I guess you're getting keen to fire her up and see how the new turbo performs .

Heh heh ....Theres always the option of going shaft powered once your afterburner tests are completed ;-)

30-40 SHP would get you mobile

Cheers
John

[slittlewing]

Haha yes it is sort of amusing how it can bite you in the arse in the latter stages!!

I am keen to fire it up, however I want to make sure the control system is improved. So After thinking about this for a while, I designed a new one (version 2) in November and now have the PCB ready to be soldered up, which will need fitting.



It’s got the Anti EMC power supply on the board and more efficient circuit and High side drives (same as new kart AB PWM tester). It also has a self measurement on the battery voltage because I found all the pumps (and therefore oil/AB pres) slowed as the bike runs lower on charge so this way compensation can be applied.
However the main reason for the upgrade is that after the oil pressure issue before, I realise I need a rock solid thermocouple measurement for oil temp. I have switched to a different thermocouple measuring chip which spits out 0-5v instead of the old one that “communicates” via a data bus which always got upset by the spark units. Fingers crossed it’s better.
One more mod... there will be two external knobs (pots) so I can adjust things from the handlebars such as afterburner fuelling or oil pressure or idle. It was a mammoth pain having to shut the engine down and reprogram changes before instead of being able to do them on the fly, so this should speed up the process of “tuning”.
If the pcb works that is.....!

Ha don’t try and tempt me with freepower! This bike will stay afterburn, it’s too packed in the frame as it is for my liking.
Luckily I have a more suitable second project that might benefit from that in future 😉

Cheers
Scott