Test Equipment Anonymous (TEA): Discussion and Group Therapy thread Part 2

[Zenith]

so who broke the first thread?

We all did - by reading the posts!

Is it broke for good or can it be fixed? Would hate to lose all those posts.

Without looking at it in any depth, I would have thought our kind host could set the view count back to zero, and it would be good for another whatever it was, 2^24 -1, views. It would be a shame if the old thread was inaccessible, as a lot of useful information from it came up in searches.

[tggzzz]

We have become risk-averse (in order to avoid the cost of accidents), yet have failed to consider that attitude's inevitable consequence. We should consider allowing people who feel they're ready to go to do so before they're screaming inside yet near-comatose on a hospital bed drugged up with morphine. It's a serious thought and I presented it in a frivolous way, but it's one that society needs to stop shirking.

I disagree about the reason we have become risk averse. The consequences of non-fatal accidents are "unpleasant".

I remember reading an article where a (US) doctor near retirement stated that after 75yo he would refuse to have major medical interventions; antibiotics, painkillers OK, but major cancer therapy not. Why? Because he had repeatedly seen the toll on the patients, and compared it with the quality of the little extra life. Of course US doctors have to demonstrate money earning capability and be able to deflect "you didn't do X" lawsuits, and so probably push mre treatment than "desirable".

I also remember a case affecting a friend (who Zenith has met). A glider crashed spectacularly, and my friend had recently inspected it and stated it was airworthy. That worried my friend, unsurprisingly. It turned out the pilot had deliberately crashed it to commit suicide.

I the light of the recent House of Commons vote, I ought to go and collect 100g of yew needles. "Be prepared" is one of the two mottos i think are worth remembering

[Zenith]

We have become risk-averse (in order to avoid the cost of accidents), yet have failed to consider that attitude's inevitable consequence. We should consider allowing people who feel they're ready to go to do so before they're screaming inside yet near-comatose on a hospital bed drugged up with morphine. It's a serious thought and I presented it in a frivolous way, but it's one that society needs to stop shirking.

It is a serious thought. I don't believe the cost of accidents is the main driver. There are vested interests selling products to keep us safe and there's the assumption that the state can and should be responsible for just about everything.

When the Titan submersible imploded there was an outcry about how such a dangerous contraption had been permitted to operate unlicensed. My view was that intelligent and wealthy people had come to an untimely end having signed extensive disclaimers, and ventured into the deep ocean in a device they should have known was a wind and prayer design. So what?

Attitudes differ from country to country. In the UK ibuprofen can be bought easily in supermarkets. In France it's a prescription only drug. In France you can buy acetone in 1 litre bottles in supermarkets. When I bought a very small bottle at the local chemists I was asked all sorts of questions about why I wanted it and did I realise how dangerous it is. You can mix it with hydrogen peroxide to produce a dangerously sensitive high explosive. Since I wanted it and didn't want to go on a watch list, I played it straight and didn't wind them up by explaining that among other uses, it's a very good solvent for nitroglycerine, and by the way, although they sold glycerine BP could they source dynamite grade glycerine.

Assisted dying is a complex subject.

Even more things we can have an extensive chat about at the next radio rally.

[Zenith]

I also remember a case affecting a friend (who Zenith has met). A glider crashed spectacularly, and my friend had recently inspected it and stated it was airworthy. That worried my friend, unsurprisingly. It turned out the pilot had deliberately crashed it to commit suicide.

I'd chatted with him online on another forum about, I recall radios, for gliders and safety standards. The logical conclusion was that gliders should have the triplicated systems used in trans-oceanic airliners with regular and expensive certifications. Meanwhile is there an actual problem with gliders having less than bombproof radios and instruments? Much nuisance and expense is caused by addressing things which might theoretically be problems, but in fact are not.

[EC8010]

Agreed on the consequences of non-fatal accidents. Apparently, the introduction of mandatory motorcycle helmets reduced the number of quality kidney donors. And certainly agreed on the major cancer therapy. I had to look up yew needles. I've learned something today.

Also agreed on the Titan. Whether or not the design was competent, they were doing an obviously risky thing. If I was offered a ride on a space rocket, I'd go. Even though you are sitting on top of a structure having the structural integrity of a soft drinks can filled with highly corrosive and poisonous fuel, unstably balanced on a bonfire, with a resulting 1% failure probability.

As a child, I bought a bottle of chloroform from the chemist. They wanted to know what it was for and I explained that I wanted to weld Perspex together. I discovered that welding Perspex requires serious clamps as well as the right solvent. Didn't know about ibuprofen and acetone. Another thing I've learned.

Yes, a cheerful chat at the next radio rally.

Does a glider really need a radio?

[tggzzz]

I also remember a case affecting a friend (who Zenith has met). A glider crashed spectacularly, and my friend had recently inspected it and stated it was airworthy. That worried my friend, unsurprisingly. It turned out the pilot had deliberately crashed it to commit suicide.

I'd chatted with him online on another forum about, I recall radios, for gliders and safety standards. The logical conclusion was that gliders should have the triplicated systems used in trans-oceanic airliners with regular and expensive certifications. Meanwhile is there an actual problem with gliders having less than bombproof radios and instruments? Much nuisance and expense is caused by addressing things which might theoretically be problems, but in fact are not.

Erm, they don't.

I've never flown in a glider with a radio; they aren't necessary unless you want to enter controlled airspace. Everything in class G airspace is "see and be seen". One consequence of that is that, regrettably, I'm now less aware of roadsigns but hopefully keep a better lookout for danger approaching from usual quarters.

Having said that, commercial drones can't keep a lookout i.e. can't "see". It looks like ADSB transponders will be mandated, even in aircraft without electrical power. Go figure.

As for instruments, they all lie in various important ways. Altimeters don't tell you your height. Airspace indicators fail, classically bees and raindrops get in the input; in my case it was an errant flap of rubber. Due to that, we are taught to make a complete flight without instruments; yours are covered up but the instructors aren’t. What you do rely on is the feel and sound to judge airspace, and your eyes to judge height (e.g. if you can make out care windows then you ought to know where you will shortly be landing)y

[EC8010]

Moving on swiftly, I've just bought another Weller TCP soldering station. I got an email from a friend to, "Come round ASAP, there's a spectrum analyser and oscilloscope you'll want." It was his next-door neighbour's who had died recently. The oscilloscope was a Gould and would probably fetch £25 at a rally. The spectrum analyser was an HP but quite elderly, with all-analogue controls, plus a fault. It was a true boat anchor and probably worth £25. But I spotted the Weller and offered £10, which was accepted. There was a Myford ML7 in lovely condition and quite well tooled, but whilst two lathes are useful, a third isn't. But I gave the son some advice on selling it and its tooling.

[Zenith]

I also remember a case affecting a friend (who Zenith has met). A glider crashed spectacularly, and my friend had recently inspected it and stated it was airworthy. That worried my friend, unsurprisingly. It turned out the pilot had deliberately crashed it to commit suicide.

I'd chatted with him online on another forum about, I recall radios, for gliders and safety standards. The logical conclusion was that gliders should have the triplicated systems used in trans-oceanic airliners with regular and expensive certifications. Meanwhile is there an actual problem with gliders having less than bombproof radios and instruments? Much nuisance and expense is caused by addressing things which might theoretically be problems, but in fact are not.

Erm, they don't.

I've never flown in a glider with a radio; they aren't necessary unless you want to enter controlled airspace. Everything in class G airspace is "see and be seen". One consequence of that is that, regrettably, I'm now less aware of roadsigns but hopefully keep a better lookout for danger approaching from usual quarters.

Having said that, commercial drones can't keep a lookout i.e. can't "see". It looks like ADSB transponders will be mandated, even in aircraft without electrical power. Go figure.

As for instruments, they all lie in various important ways. Altimeters don't tell you your height. Airspace indicators fail, classically bees and raindrops get in the input; in my case it was an errant flap of rubber. Due to that, we are taught to make a complete flight without instruments; yours are covered up but the instructors aren’t. What you do rely on is the feel and sound to judge airspace, and your eyes to judge height (e.g. if you can make out care windows then you ought to know where you will shortly be landing)y

I believe with powered aircraft there are licences with instrument ratings. They are taught to rely on the instruments even when instinct tells them not to. There are instances of people flying upside down and not realising it. There and again they are probably flying in conditions no sane glider pilot would contemplate flying in.

Is there any serious incidence of glider pilots crashing and damaging people or property? I suspect not. So a it's a non-problem which doesn't need a solution. I heard that balloon pilots are supposed to use air-band radios and have a dedicated channel or two. Most use mobile phones. They take off when the winds are right and usually manage to set down in fairly large designated areas. There are very few instances of crash landings with disastrous results.

[tggzzz]

I believe with powered aircraft there are licences with instrument ratings. They are taught to rely on the instruments even when instinct tells them not to. There are instances of people flying upside down and not realising it. There and again they are probably flying in conditions no sane glider pilot would contemplate flying in.

There are IFR (instrument flight rating) requirements for flying in clouds, licences for using wireless telegraphy equipment, etc. Artificial horizons are used in clouds; if power fails then there are mechanical "turn and slip indicators".

Not all glider pilots are sane; in competitions they are prone to pushing the envelope. Flying backwards and tumbling is traditional in aerobatic competitions.
https://youtu.be/TR7lg12b-N4?t=110

Poles have a tendency to be adventurous, e.g. wing walking (and I don't mean tied to a fuel tank!)
https://youtu.be/x3c__hg1A1A?t=53

Is there any serious incidence of glider pilots crashing and damaging people or property? I suspect not. So a it's a non-problem which doesn't need a solution. I heard that balloon pilots are supposed to use air-band radios and have a dedicated channel or two. Most use mobile phones. They take off when the winds are right and usually manage to set down in fairly large designated areas. There are very few instances of crash landings with disastrous results.

There are no "designated areas" for gliders (and I presume balloons). You run out of "up" and have to select an available field.

IIRC the rules are 3000ft above built up areas, must be able to glide to fields. Sometimes the airfield is next to a built-up area
http://news.bbc.co.uk/1/hi/england/oxfo ... 682575.stm

I've had two friends die, one a stall/spin during an outlanding, one (who I've flown with in his mid-late 80s) misjudged too many things and made the national news
https://www.bbc.co.uk/news/uk-england-g ... e-53922217
https://www.gov.uk/aaib-reports/aaib-in ... 5-e-g-cfst

[Robert]

Can't agree on Titan. Have you read the NTSB investigation report? The owner, Stockton Rush, was either deluded, a fraudster or possibly both. He ignored professional advice and appears to have deliberately concealed shortcomings in the vessel and actively avoided the legislation relevant to passenger carrying vessels. The wealthy people who went with him can't have be expected to know that the basic design was flawed. It compromised safety to get more (paying) people in.

A lot have gliders do have radios. They have their own dedicated frequency. Rather oddly you don't have to have a Flight Radio Telephony Operators Licence in the UK if you are the pilot of a glider and only using that frequency. Even 10 years ago some gliders were still using Pye Bantams as they were approved and low cost. Some quite sophisticated aircraft proximity warning systems were developed for and are used by gliders e.g FLARM. They are spreading to some powered aircraft too.
Many years since I've been in a glider. I do have a FRTOL as ell as marine and amateur radio licences.

[tggzzz]

The safety aspects of FLARM are a little subtle.

Only gliders use it, and it is incompatible with other traffic using ADSB.

It is undoubtedly very good on ridges where you are likely to have other glider(s) at the same height and going in the opposite direction. At a closing speed of 120kt, a 1m2 white blob isn't easy to spot. OTOH, it is a distraction for beginners and in the circuit, where you really ought to to be watching to see whether someone has poached your strip of grass.

I agree about Titan. Rush chose to override repeated credible safety warnings, both theoretical and practical e.g. "bangs" occurring at reducing intervals.

[EC8010]

I went on Concorde today. Not flying, sadly. Concorde 002, which was an engineering test bed, and now lives at Yeovilton. Fascinating. There were six seats at the back and the rest of the cabin was filled with 1960s data recorders. Probably FM tape-based. The cockpit was tiny and surprisingly simple. The control yokes were sit-up-and-beg handlebars with fewer controls on them than a contemporary BMW motorcycle.

At the estate sale on Monday, there was a bookcase, so I had to see what was in it. A copy of the Radio Designer's Handbook still with its original fly cover was tempting, but the book that really caught my eye was "How To Make Better Landings (Revised edition)"

[tggzzz]

I wonder what the revisions were, and what caused them

The book I liked most was "Stick and Rudder", from 1944. It points out that, contrary to imagination, the elevators don't control elevation and the engines don't control speed. In reality, and it is obvious once you understand it, in a balanced aircraft you use the engine to control height, and the elevator to control speed. (Balanced meaning that the lift=weight and thrust=drag).

[EC8010]

Exactly my thought. I thought of you when I saw it, but (sadly)I didn't have room for books.

I had not thought about the effect of engine and elevators before, but I see what you mean.

[Cubdriver]

Pull back on the stick and the houses get smaller. Keep pulling back on the stick and the houses get bigger again.

Getting some sailplane time certainly helped clarify the whole pitch controls airspeed/power controls altitude concept. I too bought a copy of Langeweiche's book back in 1990 on the suggestion of one of my sailplane instructors - it's definitely something every flyer should read.

-Pat

[tggzzz]

Pull back on the stick and the houses get smaller. Keep pulling back on the stick and the houses get bigger again.

And, if you get it just right, it becomes very quiet, the horizon moves rapidly upward and then the houses whirl around once every 3s or so. If you don't stop the whirl and then dive harder at the ground, the result is strawberry jam.

I was taken into my first spin by a name familiar to any glider pilot, Derek Piggott. https://en.wikipedia.org/wiki/Derek_Piggott
He also did many other notable feats in aircraft of various sorts, e.g. SUMPAC and "...he ended up flying through the wide span of this bridge in Ireland 15 times and 17 times through the narrower span. The two Fokker Dr.I replicas had about 4 ft (1.2 m) of clearance on each side when passing through the narrower span"

[Zenith]

At the estate sale on Monday, there was a bookcase, so I had to see what was in it. A copy of the Radio Designer's Handbook still with its original fly cover was tempting, but the book that really caught my eye was "How To Make Better Landings (Revised edition)"

I've got a copy of the Radio Designer's Handbook 4th edition. It's a tome. "This is the classic reference handbook for all who are interested in the design and application of radio receivers and audio amplifiers, and deals with basic principles and the practical design of all types of classic radio receivers, audio amplifiers and record-producing equipment up to the invention of the transistor." Essential for those of us interested in valve junk.

You can buy the reprinted 4th edition on Amazon - £170 used in very good condition. Depending on what they wanted for it, it may have been a bargain and essential bedtime reading, and at least very flippable. At 1500 pages they'd have been stretching things to call it a pocket guide.

[EC8010]

There used to be a bridge near Winchester known as the Spitfire bridge because local lore said a Spitfire was flown under it. Turns out it wasn't a Spitfire:

https://www.sabre-roads.org.uk/wiki/Spitfire_Bridge

RDH4 now turns up at radio rallies for about £30 (there was one at Rugby). I paid £70 for my copy over twenty years ago and it's missing its fly cover. It is indeed a tome and would only be a pocket guide if you were a poacher. It has to be read carefully because all of what was written about loudspeakers is wrong (pre-Thiele & Small).

I have just made sense of the Keithley 610C circuit diagram. Drawn by a nutter, the input stage (where the unobtainium input MOSFETs are) is upside down with positive rail at the top and negative at the bottom. The unobtainiums are P-channel enhancement MOSFETs. If my £10 610C has destroyed MOSFETs, they will be replaced with DN2530N2 N-channel depletion MOSFETs. This would necessitate a few changes:

• Swap the wires to the wipers of the medium and coarse zero switches to obtain correct polarity

• Tweak amplifier compensation to achieve stability (LTspice suggests it would oscillate)

• Reverse connections of the protective devices on the sub-board (not shown on the circuit diagram), or just remove them; they would probably be blown-up anyway

I have checked, and DN2530N2 has nice low gate leakage current (about 2fA). More importantly, I have lots of them.

[Zenith]

I have just made sense of the Keithley 610C circuit diagram. Drawn by a nutter, the input stage (where the unobtainium input MOSFETs are) is upside down with positive rail at the top and negative at the bottom. The unobtainiums are P-channel enhancement MOSFETs. If my £10 610C has destroyed MOSFETs, they will be replaced with DN2530N2 N-channel depletion MOSFETs. This would necessitate a few changes:

• Swap the wires to the wipers of the medium and coarse zero switches to obtain correct polarity

• Tweak amplifier compensation to achieve stability (LTspice suggests it would oscillate)

• Reverse connections of the protective devices on the sub-board (not shown on the circuit diagram), or just remove them; they would probably be blown-up anyway

I have checked, and DN2530N2 has nice low gate leakage current (about 2fA). More importantly, I have lots of them.

Be sure to post a write up on here.

I bet you're glad you didn't part with more than a tenner for the 610C.

[EC8010]

Yes, £10 was the right price. Of course, there's always the possibility the MOSFETs aren't blown up. Remote, but possible. I am awaiting UHF-BNC adapter to allow me to connect the 610C to current source and find out. Meanwhile, I have cleaned all the calibration stickers off. It's very nicely made inside. If repair is necessary, it will be written up.