The Call of Cthulu...

[cabbage]

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

[John Branch]

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

[cabbage]

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

[John Branch]

Ralph,
Surely Watts are OK?

John

[cabbage]

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

[John Branch]

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

[cabbage]

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

[John Branch]

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

[MikeWilliams]

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

[cabbage]

There is a page on wikipedia...

https://en.wikipedia.org/wiki/M-497_Black_Beetle

be afraid -be very afraid!!!

regards

ralph

[MikeWilliams]

Oh my gosh!  Now I understand!

Mike

[cabbage]

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

[cabbage]

as promised.

[blagdon]

We have a NYC video with the beauty running, great choice of project a usual Ralph!

[cabbage]

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