Posts by lampbus

As a uni placement student I wrote a full screen 'analogue' clock display.

In EBCDIC.

on IBM system/36 attached greenscreen terminals (of various types).

Using RPG II and the SDA...not really designed for animated graphics, but it worked !

EU company that has done quite well :

ARM

They also have failed to correctly install the gas springs that support the cockpit cover.

http://www.industrialgassprings.com/uk/calculate_basics.asp

They could use the fully damped type, but they are significantly heavier for the same amount of push.

I have a Samsung laptop - about 2 years old.

About 6 months ago I noticed intermittant charging / output from the PSU block...so I investigated expecting it had failed.

I found the power lead (UK plug to cloverleaf socket) was very hot and plastic melted at the cloverleaf end. Not from the PSU block, or bad contact in the pins, and it was intermittant when I flexed the lead/strain relief.

I dissected it - bad assembly of the conductor to pin - all nicely molded up in solid plastic.

It would have probably have lasted as it spends most of its time static on the floor ... until I took it on a couple of trips and the wrapping and bunging in the bag precipitated the failure.

And Fusion of course...

Its crazy that politicians are scrimping on the ITER project which will cost the world only about as much as a couple of olympic games...

(Or a crossrail phase 1. Then there will be a phase 2 and three at another 15 billion each)

(Were the London Olympics worth it? 14000 athletes at 9 billion pounds = c650,000 per athlete for a 2 week event !)

It is odd we can throw away cash like that for a bit of immediate sport gratification but cannot see further than 10 years ahead for the big important stuff.

It is sad to see - lots of people work really hard to make these things happen.

Spacex have had their near misses too - https://www.youtube.com/watch?v=nxSxgBKlYws

I was watching this live and thought...hmm, that 90 degree roll at launch dosn't look healthy.

This Antares launch looked slightly odd right from the start - to me it seems like the hot end drifts slightly to the left (towards the launch tower) at release, then corrects a couple of seconds later, but it is hard to tell as the camera is moving a bit too.

In my day at Uni, we learned concepts using PASCAL, then MODULA-2...which was good for me as I had done all my previous learning in BBC Basic. I just loved procedural programming and recursion.

Found this lovely mess of logic last month : http://interactivestructures.org/

Chap claims he is a programmer...and was employed as a lecturer at Yale !

Like an 8 pin dot matrix printer...

I think (and tell people who can remember them) that 2014 3D printing is like 1982 dot matrix printing. Noisy, slow, bumpy, feint, fanfold fed (didnt fit A4 folders) monochrome etc.

I used it to print program listings. I tried to print graphics. I had an old moveable type press for crisper output. Other people used linotype? systems to produce blocks of text that were pasted up and rephotographed to make print plates. I had a pen plotter for linear stuff. Horses for courses.

But I too hate the media hype around 3D printing - and I do remember massive media hype around 'desktop publishing'.

Like the dot matrix printing dumped the pins...3D printing will probably dump the squirty plastic nozzle of curent designs in order to move on. But it is the software that is also driving this revolution. Slicing CAD models for printing is like the screen dump printer driver I wrote : part of the system that can make a useless lump of mechanism perform better, and the basic ideas of rasterising/slicing form the basis for newer mechanics to perform better.

Its OK, I have a Samsung...

...But I was sitting one evening and my backlight flickered. Hmm I thought, Is that related to the electrical magic smoke smell that is now drifting past...

Yes. The mains power lead was all hot and bothered at the clover connector. I mined into the plastic (having unplugged it) and the termination didn't look too good.

All is well - I went and dug out a replacement lead from my old laptop parts pile. OTOH, perhaps I should be worried - the old lappy was a HP...

Waggle Worry

I like the 15 second canard waggle, but what steps have been taken to prevent launch in mid waggle ? could be a big problem as the acceleration due to rocket is probably massive compared to the time taken for the servo to return to neutral.

Lockdown

A RC helecopter friend swears by : nordlock washers : for preventing threaded things becoming unthreaded. I use them extensively on my engineering projects where we really don't want things falling off.

Magnets...but with a difference

Magnets to attach the power wires.

Yes they have been suggested and found to be too strong to just pull off but...don't just arrange for them to direct pull.

Magnets are strong close up, but the pull drops off rapidly so only small motion is needed. Thus arrange for the lead wires to run along a lever so that the force to pull the connections is minute.

Keep the wires and levers lightweight but stiff (carbon fiber etc.) so they don't contribute significant force on t6he magnets during jiggling.

---------------------------------------- rear face of rocket

..........................O

_____________O__V_

(

)

Key: (=wire. _ = lever O=magnet pair with contacts between V=fulcrum fixed to rocket ....=space so the ascii art works.

At rest, there is a small gap between the lever and the fulcrum point. As the rocket starts to move, the feed wire tensions, loads the lever that can rock until the fulcrum makes contact and the magnet is popped apart and hangs free. The end of the lever could even strike a tag fixed to the flying truss instead of loading the wires.

Use both.

As others have already said, you don't want to fire before balloon burst cos that would be silly. And not optimum mission.

Detecting burst is simple - tension on the support string will almost instantly drop to zero. Depending on rate of climb, G will decay to zero - she has mass and will continue to ascend after loss of baloon lift. This decay will be quite rapid too.

Potential problems : Swinging about could cause a false trigger - having seen a couple of other project videos with alarming swinging going on. This is where the barometric is used - to inhibit firing below a chosen altitude. THis will aid ground handling and launch.

Stability after burst is a big problem, but a pre-deployed drogue 'chute just below the balloon would help there. This would not cause significant drag on ascent and may also help dampen out swinging etc on ascent - the baloon is a large spring in itsself.