ScottsCrazyBuilds Jet Kart

[jetric]

Andy,
You are the one that needs to get a grip, oh I must of been seeing things then, the turbo was on the bench under the drill press in your workshop, and why would I ask to buy it if it didn't exist.
OK Dan must of been bullshitting me then as he told me that after you had fell out with him because he had put the peel car bodywork on his kart, or am I making that up aswell,
So me and my brother didn't do any work at the Discovery channel filming, we only drove mine and his jet karts up and down the strip at santa pod with the cameras on plus the film crew did shots from behind my kart and the camera man said that he didn't realise how powerful these karts were as his camera nearly got blown away, it was a good job that me and my brother went as it was only our karts that were working on that day as Andy plezesco couldn't start the jet mini and you had some issues with yours or Dan's kart (whichever one you took?).
But as you say, me and my brother did nothing!! So it must be the truth.

Richard S.

[andym]

Oct 26, 2022 11:05:09 GMT -5 jetric said:

Andy,
with regards to the commercial jet engines that I own I have had to graft my arse off working at my friend's workshop on his commercial jet engines in order to earn the money to buy them, it has taken me 25 years of blood sweat and tears to get them, my brother martyns cars he has had to work full time at his job in the week plus working every weekend at another job for the past 15 years in order to save up for it.
Or we could of just done it the easy way and gone bleeting off to a load of crowd funding schemes, just £3 a month!!
I don't go driving around in a maseratti like you do, or have the money to buy a one year old Mercedes Vito van and a brand new Ifor Williams box trailer and own a Porsche boxter.
As Adrian Bennett said, Andy Morris is the most worse off, well off person he knows!
I will always appreciate the fact that we got into santa pod because of you, there's no denying that! But a majority of the times I went there it was on a 'run what ya brung' event that you just pay £25 to attend, anybody can go to these!!
Yes you did get us to Rockingham but then again it was in the early days when you were a friend before you started back stabbing me with Dan.
Just for your information kart 6inch rims have nearly the same outside diameter tyre as a standard kart wheel/tyre because the 6inch rim tyre is a low profile tyre. Also aircraft runways don't normally have pot holes in them, aircraft don't tend to agree with pot holes!!

Richard S.

What money I have or dont have is none of your business, I thank you, to not talk about it in public forum. Just like I have no interest in what you or your brother have or dont have.... I only replied before to retort on what you said, but still you bring it up.... Clearly also bitching behind my back to others

But I guess you just showing your true colours...... real crass.... ( I drive round in Bentley now) but still got nothing to do with you 

[jetric]

Andy,
Also what me or my brother own has got absolutely nothing to do with you, so please don't publicise it here on a public forum.

Richard S.

[andym]

Oct 26, 2022 12:40:33 GMT -5 jetric said:

Andy,
Also what me or my brother own has got absolutely nothing to do with you, so please don't publicise it here on a public forum.

Richard S.

Erm you brought money up first, only broght it up I reply to your comment, but again after I said dont bring it up..... you did ??

Remember you say I rented Elvington for the day..... total Lie and fabriction on your behalf. but you said "you did not have that kind of money," it was in retort to that

Again and again.... there was no 3rd turbo.... if the had you could of had it, i shared the s4 with evry one. What reason is there to lie..

That you then put that about money,  well just..... well, what ever.... we can all see now.... 

 

[jetric]

Andy,
remember you started slagging me off first on this thread and I'm not just going to sit back and accept it!! I didn't start this, but as always you have got to have the last word and be right!!

There is always two sides to every story, but apparently your side is always right.

I'm done with replying now as this is totally rediculus.

Richard S.

[andym]

Yes two side, but when one side makes it up... like the elvington thing.... delusional

[slittlewing]

Repetitive, tiring bullshit as always Andy. I can’t imagine why you have fallen out with so many people.

Maybe I should rename this thread the “AndyM EGO / infinite circular tantrum” thread. It’s fucked anyway so I might aswell 😂

Or lord of the rings, Jet edition (ohhh “my precious” AB ring)… 😂😂😂

Get as butthurt as you like that the kart afterburner didn’t work before I had it. It’s a factual statement proven by your own video.

Cant be arsed to waste my time any further on you.

[andym]

Oh so now "it did not work before" , a change of the story again.... liar.... you put me, my work down...Other day you telling us you made changes because you wanted to...... the engine worked fine before you had it, before you messed with the fueling, and messed the start up....My factual statement... no it did not work in that video true, but would of.... yet another change of tune by you.... YOU HAD BEEN SAYING IT DID NOT WORK. as in would not work..... period. Like all liers when found out you try to tell the story another way to get out of it.

Who have a fallen out with.... or is it i dont like liars, people that dont have any common curtesy or loyalty

Like I have said Scott, delusional, you change your tune, more than a watch changes time

[andym]

Sorry every one

Richard i had no issue with yours brother kart, it was put together very, very well.... the engine you built was ahead of so many

Why would i get him in with the rest of us at Flame & Thunder, Santa Pod

Send pictures and copy for entry in the program, for the event, share video on my channel of it ( before you go about it being for the money i get, you or he can have the pence its earnt me )

Book and pay for accomadation for him.... (which took weeks to get the money back off him, what was it "Andys loaded", it dont matter... am not, and it does, did it to try and help us all out with the cost, group booking discount)

To have him turn up.... No kart.....  dont even ring to tell me he was not going to bring his kart. Hes in the program etc....Happy to have the tickets.... No common curtesy, nothing. Did not expect any one to answer to me, but you would think any right minded person would call and say sorry. His reason... worried about getting it stolen.... there  are top fuel dragsters packed up over night, Firer Force etc..... others left theres overnight...Dan Goodwin, Andy P, Me and even you Richard. The lack of respect towards others in the group that had turned up to do the show. In the eyes of the event organisers... ? but dont make us look good.

So you see Richard and every one esle, no issue with his kart... happy to see it being built, bring higher standards to the hobby.... But saddley wanted nothing to do with your brother.... But by all means keep making things up Richard, to justify your world view.

[finiteparts]

Scott and Andy,

Just a suggestion...I think that you should consider making the NGV plate and turbine backface two separate parts. Having them thermally close-coupled is likely the reason that you are seeing the plastic deformation and may be a contributor to the turbine backface rubbing.

The logic here is that the NGVs will experience very large convective heat transfer rates while the turbine backface region, which is in contact with the aluminum bearing housing, will experience much lower temperatures due to the lower hotside convective heat transfer and intimate contact with the very high heat sink capability of the aluminum bearing housing and oil flow. The center of that part is going to be cold with the outside being VERY hot. The hot side will try to grow away from the center and be in compression, with the cold center being in tension.

The one thing you learn when you work on designing hot structural parts is that you cannot fight thermally driven mechanical strains, thermals will always win.

Scott, I did a hand calc and estimated about 4290 lbf of "blow-off" load (I used 65 psia internal pressure to bound it) on the back plate of the engine casing, which seems pretty low to cause the whole of the NGV to move forward, but it may. Have you done any calculations to see what kind of strain that would produce near the locations of the rub? If the part is 304SS, it does have shit for load capability at high temps and it has a very large thermal expansion, so it may be an issue....not ruling it out, just based on my experience (which does not include using 304SS in high temp applications) it seems low.

In my experience designing engine hardware for industrial and flight engines, thermo-mechanical strain is usually the biggest problem, pressure loads are not usually even in the same order of magnitude and thus rarely contribute significantly to problems.

Just a thought to help getting everyone's creative juices flowing and maybe start a creative discussion.

- Chris

[andym]

Oct 30, 2022 15:06:32 GMT -5 finiteparts said:

Scott and Andy,

Just a suggestion...I think that you should consider making the NGV plate and turbine backface two separate parts. Having them thermally close-coupled is likely the reason that you are seeing the plastic deformation and may be a contributor to the turbine backface rubbing.

The logic here is that the NGVs will experience very large convective heat transfer rates while the turbine backface region, which is in contact with the aluminum bearing housing, will experience much lower temperatures due to the lower hotside convective heat transfer and intimate contact with the very high heat sink capability of the aluminum bearing housing and oil flow. The center of that part is going to be cold with the outside being VERY hot. The hot side will try to grow away from the center and be in compression, with the cold center being in tension.

The one thing you learn when you work on designing hot structural parts is that you cannot fight thermally driven mechanical strains, thermals will always win.

Scott, I did a hand calc and estimated about 4290 lbf of "blow-off" load (I used 65 psia internal pressure to bound it) on the back plate of the engine casing, which seems pretty low to cause the whole of the NGV to move forward, but it may. Have you done any calculations to see what kind of strain that would produce near the locations of the rub? If the part is 304SS, it does have shit for load capability at high temps and it has a very large thermal expansion, so it may be an issue....not ruling it out, just based on my experience (which does not include using 304SS in high temp applications) it seems low.

In my experience designing engine hardware for industrial and flight engines, thermo-mechanical strain is usually the biggest problem, pressure loads are not usually even in the same order of magnitude and thus rarely contribute significantly to problems.

Just a thought to help getting everyone's creative juices flowing and maybe start a creative discussion.

- Chris

Hi Chris, thank for comment, all i will say is they are, well kind of , they have lugs that are engaged.... and they was tacked together.... to allow some flex.... for some reason they have now been welded together ? so any flex removed, tacks could brake before back playe pulled forward. Running engine past it 40 psi limit, would bend things.... About all in want to comment on..... thanks again 

[racket]

Hi Chris

Yep , thermal loads even make the bottom of our frypans warp :-)

Our relatively large diameter NGV compared to a similar flowing axial wheel NGV does create a lot of problems , I try to have as much "blanket" cooling as possible to minimise the temp variations .

Having a slipjoint at the exhaust stub unloads the NGV from airloads and is the easiest solution .

Cheers
John

[slittlewing]

Hi Chris, John

Its an interesting point about thermal loads vs pressure loads and which might be the biggest factor in terms of permanent warping.

If pressure loading is the biggest factor, a slipjoint should fix it.

If temperature is causing the warping, taking Johns "frying pan" example - the NGV should surely be hotter on the flametube side (expanding) than the turb wall side (compression) causing it to bend towards the turbine. This seems the opposite of expected with hot combustion gases against the turb side and no direct combustion gas contact on the FT side (albeit a few mm from the FT back wall and seeing an unknown amount of radiant heat).

So it feels more likely to be combination of both - softening of the 304 from general high bulk temperature, combined with pressure loading in the rearward direction?

Chris when you say having the NGV and turb backface as two separate parts (presumably as per a normal turbo, with the thin pressed heatshield behind the turbine) - That would require a gap and therefore the NGV fins being supported by a wall which reached further forward than the existing shaft tunnel back face. (So quite a big design change)

Cheers

Scott

[racket]

Hi Scott

One of my original designs for my FM-1 engine was to have things seperated but I found there wasn't enough axial length available after machining up some wooden test pieces , so went with the design I've been using for all my engines , plenty of cooling airflow to try and provide seperation of hot gases from wall material , combined with the slipjoint at the exhaust stub , never had any problems ..........thankfully :-)

Cheers
John

[finiteparts]

Scott,

I agree that it does appear to be opposite of what you are seeing, but when you are well into the plastic deformation regime, the path to deformation is not always as clear as it is in the elastic regime.  I am working to test out a low cost FEA program (LISA FEA) and I thought that this was a good opportunity to test the arrangement of this style NGV, as I am also curious about how your part became deformed.

Here is a steady state thermal analysis run (deg F)...I took some liberties with the model to minimize the node count of the mesh. 



I assumed a inlet total temperature of 1800 F, an average NGV throughflow Mn = 0.7, backsize gas temp pf 450 F with a very low velocity (thus low HTC) and a bearing housing temperature of 250 F.   I won't go into how I calculated the heat transfer coefficients (htc's), other than to say that I have a nice Python script to calculate them based on Mach number and other factors...it is quite involved and a whole topic unto itself.   All just SWAGs...but it should be close and show the trend well enough.





I then transferred the temperature results into a Static 3D analysis.  One of the complaints that I have (and maybe I just haven't found it), is that LISA doesn't allow the material properties to be curves based on temperature.   So, I had to estimate the average temperature and set the Elastic Modulus, Poisson's ratio, thermal conductivity and thermal expansion at a single temperature, which I took to be 1000 F.  SO not as good as ANSYS or some of the higher end FEA preprocessors, but for the very low cost, it is pretty solid.  I only constrained the body at the bolts and also applied a pressure boundary to simulate the backside engaging the bearing housing.  Another gripe is that they don't have cylindrical restraints or similar that are so handy on cylindrical bodies.  

So here is the deformation (in inches) that the body wants to experience solely due to the thermal loads.  I did a cut-plane image to help make it more clear...I would like to be able to highlight the cut-plane elements to really show the cut surface, but it is also nice to see the through thickness gradients.  





Now, if I was doing this in ANSYS or the like, I would refine the mesh, especially in the high gradient regions and rerun to see how much it changed, in order to understand if there is any mesh dependency, but this program runs out of juice around 85,000 to 100, 000 elements so I can't do that with this this model.  I tried to take a sector and use periodic boundaries, but the mesher couldn't generate matching node counts on the two sides due to the lean of the vane.   I may try to redo with a radially fixed vane and see if that would work...if I get some free time.

I forgot to transfer a stress plot, but from the strain plot you can see the transition from low strain to high strain at turbine backface and near the bolts.  My thought is that due to high stresses, it relieved itself by plastically deforming and then as it cooled and relaxed with the permanent deformation of the outer band locked in, the NGV outerband may have put the turbine backface region in compression and caused buckling.   It would have had to done that in a previous run with the deformation there on the run that experienced the rub.  It would be interesting to check the o.d. of the NGV assembly and see if you can measure some plastic deformation.

So to John's point, others have run with similar set-ups and had no issues, so why did you run into this, if in fact they are related?   Well, on accidents, rubs, etc., it is sometimes hard to determine cause and effect.  Is the deformation due to the local heating from the rub?  Possibly.  Could it be the built up internal stress in the part due to Low Cycle Fatigue (LCF) from the starts and stops that it has experienced? Possibly.  Could it be due to cold streaks from the tertiary jets or hot streaks from a leaky injector? Possibly. There are a multitude of things that could have played a part and the only way to figure it out is to do the calculations and then test the theory somehow.  Remember the absence of evidence is not evidence of absence.  

One thing that John mentioned is that he uses air jets to cool the turbine back-face and the windage cavity...are there cooling holes in yours?  The bore-cooling that the jets provide may help to suck some of the heat out of the backplate near the turbine backface, which may lower the thermal gradient due to local conduction near the jets.

Again, I seriously doubt the pressure acting on the casing backface is a real driver...but I am open to seeing some numbers on the stress that it would produce. I put the  4288 lbf load onto the NGV tips and allowed it pull aft and it made little difference in turbine backface axial strain.  I was playing around with things and didn't save the results...so I will have to redo it and share it later.

I also think that the mod needed to decouple these two bodies is not that tough.  I will try to sketch it out.  I was really trying to share the idea with Andy too, because he is making a new model and I wanted to give him food for thought before he starts cutting chips.  But I am not trying to tell anyone how to do their projects, just suggesting an alternative approach.

- Chris