As some people have noticed and commented - I have been "quiet" recently... However I have been investigating (!) I joined the local MES and was greeted by one of their members with a temper tantrum worthy of an Aspergers Syndrome "meltdown" upon seeing the boiler for "Southern Magyar". The design document has all the rationale and calculations within it, even taking into account the softening factor of the copper and monel metal used to build it. The primary reason was obviously that it was "different"...
At the Fosse the stand for " The Gas Turbine Builders Assoc" was opposite the G3S stand. I went across and introduced them to the concept of direct thrust locomotives...
The smallest design they "sell" is a 1.3 pounds static thrust turbine. Which is interesting - but cannot fit withing the G3 loading. The NYC black bug would require two...
However a ducted fan pair will fit, and have been ordered. The combine thrust of them is 5.6 pounds. Already you can see my problem! I am a purely metric person and will have to build a spreadsheet to work out all the forces in Newtons!!!
Oh well, at some future point a Black Bug whizzing around the MES track.
Regards
Ralph
Ralph,
According to my "Conversion Tables and Technical Data" handbook published by Bristol Siddeley Engines Ltd in 1962, the rate at which thrust does work is called the "Thrust Power" and is the product of net thrust and forward speed. If you think that your new motive power unit will achieve 10 ft/s, and doing the necessary conversions this works out at aprox 75 watts from your 5.6lb thrust turbine. My little black book will also give the answer in Sthenes and Kgf, but Newtons is only convertible into poundals (remember those?), and that is a step too far (or back) for me.
Do you think you're irate friend would be mollified if you used the S. Magyar boiler to feed a steam turbine?
John
John,
The equivalent of "The thoughts of Chairman Mao" that exists by my bed contains the scribbling and doodles that could eventually be a steam turbine loco... But more in line with the TGOV external type than a Princess Royal. The turbine comes straight out of the pages of "The Tesla Turbine" and is about thr dia of a coke can.
I have never used Imperial measurements such as foot poundals or gallons per hour. I am a Metric Colonial Brat!
Regards
Ralph
Ralph,
Surely Watts are OK?
John
I was raised in a firm Centimetre Gramme Second environment! Thus Pop worked everything out in Centimetres (the Krupps machines at Bulawayo were metric) and Mum injected accurately measured CCs of insulin into her sons backside...
If I ask my Son what a horse power is he would google it and say was 745Watts. When I came to the UK some of my classmates were more used to measuring in versts and els..
Regards
Ralph
My training was in the '60s, after school in imperial, then physics was cgs, fluids in MKS, most of the rest in imperial, modified as thermodynamics used celsius temperature measurement and imperial mixed, thus giving rise to the Centigrade Heat Unit , the CHU, which was a BTU only using C rather than F. I remember testing an engine destined for a German aircraft, and the thrust had to be quoted in something we called krautpounds-I never got to the bottom of that one.
BTW, more delving into the little black book reveals that your 5.6 lb thrust is around 25Newtons.
No wonder I can still convert £SD to new money instantly.
John
The postman is starting to wprk over time! Tje twin electric ducted fans and single Brishless ESC are en route! The main problem that has arisen is the sheer amount of power that will be running through the loco! Mostly I wire using 15A cable and fuse at 5A...
Each fan will draw 44A @ 14.4 V through an ESC rated at a continuous 100A. The peak overload factor is supposed to be 720A.
My mother always let me tap the exchange "submarine batteries" as batteries were safe...
The original had a jet pod from a B-36 and the motto "six turning four burning" comes too close to the truth...
It is going to have to be shortened by a scale nine feet otherwise the over hang will collide on corners with other passing stock. I will have to devise some form of mechanical braking as there can be no dynamic braking from a DC rotor. The shroud for the fans is going to have to be printed and the internal partions lasered onto carboard stencils.
Time for the troupe to start work!
Regards
Ralph
Ralph,
By 'ek, Ralph, how big is your charger?
Reminds me of the rocket powered sledge at Pendine, and that track ended in a 50ft high heap of sand!
We all look forward to the movie!
John
Ralph, I am totally in awe of all this but cannot imagine what it is you are aiming at. Is there a picture or drawing of something similar so I can visualise it?
Mike
There is a page on wikipedia...
https://en.wikipedia.org/wiki/M-497_Black_Beetle
be afraid -be very afraid!!!
regards
ralph
Oh my gosh! Now I understand!
Mike
Interesting morning spent playing with OpenScad... The jet pod is from a B-36 - which has been installed upside down by the NYC on top of the Budd RDC (3).
Thus working from photos of the B-36, I hope that I have something that is "right". The pod is going to have to be printed in three pieces as it is over 220mm long and my bed is 180mm sq. So, there is a front end, a rear end and the remains of the support pylon which is bolted to the roof!!!
I will upload some screen shots when I have finished lunch.
Regards
Ralph
as promised.
(https://i.ibb.co/0mTN3ky/aa1.png) (https://ibb.co/0mTN3ky)
(https://i.ibb.co/QDxtHtk/aa2.png) (https://ibb.co/QDxtHtk)
We have a NYC video with the beauty running, great choice of project a usual Ralph!
Despite the weather and flying bits of roof discussion of my new project continues in the "Standing Order". Friends have raised some interesting ideas and thoughts that I would present for discussion.
Thrust Buckets. These are the method that commercial jet liners use to brake after landing. Given the potential for a similar use - do I fit them?
Disc brakes. I think these would have to be fitted anyway to hold the bug in position whilst I wound up the fans.
Reversing! It will have to be towed back to the start - so a small shunter is required to do this. The Princess Royal required one for the same reason...
Regards
Ralph
Quote from: cabbage on Feb 09 2020 12:09Thrust Buckets. These are the method that commercial jet liners use to brake after landing. Given the potential for a similar use - do I fit them?
Reversing! It will have to be towed back to the start - so a small shunter is required to do this. The Princess Royal required one for the same reason...
Thrust buckets and reversing? Theres always as reason to behave like in real life . . . :)
https://www.youtube.com/watch?v=-Zkxh903s_w
Quote from: cabbage on Feb 09 2020 12:09Reversing! It will have to be towed back to the start - so a small shunter is required to do this.
Yup! https://www.youtube.com/watch?v=saG-QQSiG4I
Nobody thought to mount the engine pods on a turntable!? Braking and reversing solved at a stroke.
John
Any reason you cant fit a motor for braking/reversing?
Belt driven, doesnt need much torque and can be actuated by a servo?
One of the first things you'll need is super-elevation, and I mean super-super camber on the curves!
Tim,
There IS and easier method of ensuring good track adhesion and this was mooted in the pub yesterday.
"Why don't you tilt the train?"
The person who suggested this was duly castigated verbally (Martyn is ex RM). But again the idea has merit! This could be done using "saddle curves" in which one side of the loco is raised as the bogie rotates. A far simpler solution than pneumatics!!!
Having a donkey engine to pull the loco backwards rather than having a shunter is I feel "cheating"(?)
So far we have to construct ; thrust buckets, disc brakes and saddle curves -and the motors haven't even arrived yet!!!
regards
ralph
After some plotting and hmm(?) work production printing has begun. The jet shroud has been modified to fit the available fans and the wall shell thickness increased from 2 layers to 4. This gives me more to sand smooth. Printing of this should finish Monday morning. The top and bottom rear parts of the jet pod have been printed (12 hours each!) The next problem is the thrust buckets and how they angle into and out of the thrust stream. More cheese cobs and a pint afterwards -I think!!!
(https://i.ibb.co/2PqHbvk/IMG-20200215-084957.jpg) (https://ibb.co/2PqHbvk)
(https://i.ibb.co/JqQC31b/IMG-20200215-084153.jpg) (https://ibb.co/JqQC31b)
(https://i.ibb.co/hVn4kDP/IMG-20200215-084136.jpg) (https://ibb.co/hVn4kDP)
Regards
Ralph
Well after 25 hours 9 mins of printing the shroud body is complete. It is huge!
(https://i.ibb.co/pvVk3tB/IMG-20200216-084212.jpg) (https://ibb.co/pvVk3tB)
(https://i.ibb.co/gvxbt3X/IMG-20200216-084157.jpg) (https://ibb.co/gvxbt3X)
(https://i.ibb.co/jGBrjQR/IMG-20200216-075759.jpg) (https://ibb.co/jGBrjQR)
More OpenScad!!!!
Regards
Ralph
Printing is complete for the jet pod -other bits await programming. Looking at the completed jet pod, I am reminded of something CJ Walas a member of another forum once said;
"Mr Brades, over the years I have come to realise that you are the most dangerously sane person I have ever known"...
He could be right(?)
(https://i.ibb.co/F7kTw2L/IMG-20200216-151001.jpg) (https://ibb.co/F7kTw2L)
(https://i.ibb.co/tqjbGrs/IMG-20200216-150933.jpg) (https://ibb.co/tqjbGrs)
(https://i.ibb.co/G9hJ3FS/IMG-20200216-150920.jpg) (https://ibb.co/G9hJ3FS)
" The only difference between me and a madman - is the fact that I am NOT mad."
(Salvador Dali)
Regards
Ralph
That pair of pods just looks "Right". Going to add reheat?
John
John,
Thank you!!! The mind scrunching required to program an object upside down whilst having only pictures of it the right way up... The tear drop on the top of the pods is actually the case for the wing tip landing wheel. once everything is set solid overnight -it is out with the P38 and start gap filling and sculpturing. The pod is 18cm wide by 25cm long -so when it sits on the loco -you will notice it.
I think re-heat is out though!
regards
ralph
Jet pod as used on the B-36(https://i.ibb.co/rs7jRGh/B-36-engines.jpg) (https://ibb.co/rs7jRGh)Jet pod as used on the M-497 Black Beetle(https://i.ibb.co/NSYh0zq/jet.jpg) (https://ibb.co/NSYh0zq)
Quote from: cabbage on Feb 16 2020 18:43I think re-heat is out though
Hmn, I also think its just a turbojet. Mind you, given it is a 1948 design it probably would need a hefty pair of smoke generators fitted.
More pics . . .
(https://i.ibb.co/Pm4466b/01.jpg) (https://ibb.co/Pm4466b)
(https://i.ibb.co/7j59gKv/02.jpg) (https://ibb.co/7j59gKv)
(https://i.ibb.co/mHRn831/03.jpg) (https://ibb.co/mHRn831)
(https://i.ibb.co/TbwQ9W3/04.jpg) (https://ibb.co/TbwQ9W3)
Once you have mastered the ducted fan technology maybe the NYC snow blower and Russian version would be on the cards - LoL :D
(https://i.ibb.co/7JKX004/05.jpg) (https://ibb.co/7JKX004)
(https://i.ibb.co/XCxR402/06.jpg) (https://ibb.co/XCxR402)
By the way Ralph - a great piece of OpenScad work there - very impressive!
Robert,
I am sure that I have seen a picture of the russian loco with two carriages attached? Once I have made the Black Bug and completed another 2-NOL the technology may be there for more powerful smaller diameter ducted fans(?)
As to congratulations on OpenScad once I have figured out how to program the code for the Japanese loco...
Regards
Ralph
Quote from: cabbage on Feb 17 2020 09:32
Robert,
I am sure that I have seen a picture of the russian loco with two carriages attached?
You're not wrong, I'd never seen it that way - but . . .
(https://i.ibb.co/4ZWRyKR/img-413608.jpg) (https://ibb.co/4ZWRyKR)
I have ordered two 55 mm fans to build the Russian with. Thrust with the pair of them is only going to be about 10 newtons. This is less than one of the fans fitted to the Black Bug... But a more "stately" acceleration would be expected of a passenger train. The nics picture of the Russian shows it pulling more than two carriages! However a turbine car (?) plus two carriages is what it is going to be - because of platform length. The same is going to have to happen with the Japanese emu. This is going to have to be chopped down to two "ends" and a middle carriage.
Regards
Ralph
Now that I am being forced to "think happy thoughts" the postman has supplied me with items to do so! I have the 100 ampere 3-phase ESC and the cutting tools to fit my CNC router with. The nurse has been and I have assured her that I will do nothing stressful but limit the day to doodling, reading and typing.
What the troupe of machines are going to do -I never mentioned...
I will not be at the AGM as I got out of hospital Wednesday lunchtime.
Regards
Ralph
Great to hear that you are back at home Ralph. A sure those nurses did nothing for your blood pressure.
Mike
Sorry you will not make the AGM Ralph but take care of yourself and hope to see you later this Summer...
Regards,
IanT
Royal Mail has delivered the two smaller engines from China. These will be the "YAk" engines on the Russian loco. The pod for these is going to require some extreme ginger nut crunching as they will require wiring conduits inside of them. Although I am quite confident of the pod for the black bug taking the force the pod for the Russian is far more flimsy and may need some steel rod "injecting" into it(?)
Back to cutting the lawn or should that read watercress???
Regards
Ralph
After four days of pencil chewing... I "think" I have got a sequence of construction to produce the Russian jet pod. It breaks down into two jet shrouds and two half a T supports.
The main problem is going to be the front to back weight distribution. In the Black Bug the jet pod is aft of the front bogie whilst in the Russian it is directly Infront. What the noise level must have been like for the drivers -I shudder to contemplate...
Regards
Ralph
(https://i.ibb.co/L1CQ5gV/IMG-20200310-112754470.jpg) (https://ibb.co/L1CQ5gV)
This is the start of printing the jet pods for the Russian loco. They will be 100mm wide and 160mm long. Yes the loco does not fit within the G3 loading gauge - but to be honest I never thought it would!
Both the American and Russian locos will have to have very low initial rolling resistance. Thus I have been thinking about Aluminium wheels with double roller races... These I could make using the Scullin Patten for tender wheels - again to remove mass.
Everything on the Russian loco will have to be as light as possible because this has the lower power motors. Once the thrust car is done I can measure the thrust available. I f it pulls two of my LMS carriages then I know I am safe!
Regards
Ralph
Just after 1 am.. The print failed at 15 hours of running, (agh!!!!) But at least I have another Daliest pen holder for the house.
Regards
Ralph
During my enforced lay off at the QMC I did manage to get most of the source parts for the locomotive worked out. Some of the things now seem logical but insane... I plan to make the wheels from bar stock Aluminium and have thrust bearings as well as ball bearings on the wheels. Part of the R/C system is going to have to have brakes triggered from it as thrust buckets will not seem to be workable...
I am going to have shorten the overall length by a scale nine feet otherwise it will overhang into the outer curve on a corner(!)
Regards
Ralph