Here is a list of all the postings Robert Atkinson 2 has made in our forums. Click on a thread name to jump to the thread.
|Thread: £1000 to make a Spitfire aircraft fuel tank gauge. Can it be done cheaper?|
No, we are not.
Just watching this evenings episode and thy are lifting a fuselage with a ratchet type cargo tiedown hooking the end hooks together. While probably strong enough it's certainly not approved and tested lifting gear! Just to top it off they then had two guys worlking under the suspended fuselage. At £2M for a re-build you would think they could afford a proper sling / strop. Then they were fitting the wing with pictures of "fettling" a rear attchment bolt hole with a file and then driving the main spar bolt in with a hammer. Contrast recent Guy Martin Spitfire build TV program where the same bolt was precision ground to original tolerance (0.0005" IIRC) and then having to let it sit on the bench for a while because the heating from Guy holding it in has hand caused enough expansion to stop it going in the fitting.
#andhow much do you think a modern fuel gauge costs? How about $250 for a non approved one?
|Thread: Electric Smart Meters|
|Thread: High Temperature Air Source Heat Pumps for Domestic Heating|
We had a Dakin multi-split Air-Air system installed about 18 months ago. Two outdoor units feeding 5 indoor (capacity for one more). It wors really well and heating costs have gone way down. Even using it for cooling in hot weather our bills have not gone up.
The odd thing was that all the installers on the new system wanted to put single split systems (5 outdoor units) in. No idea why and unlike the system I put in the old place the two multi split outdoor units were slightly dearer than 5 smaller singles.
|Thread: Motor power|
Wiring a motor Star or Delta does not affect the rated power output of the motor. It can affect its starting performance under load but that was not the question. The key point is that the current per phase is lower for the star connection than the delta.
With a VFD it i important to note that the mechanical output power is reduced when running the motor at lower speeds. This is because power is proportional to speed an torque and torque in a motor is proportional to current. You can't drive more current than the rating so power drops with speed. Conversly power increases with speed for the same torque / current.
|Thread: capacitance in long cables|
The majority of opto-solators are analog. Only those with comparators on the output are truly digital. The problem is that the transfer function varies between devices and with temperature. To counter this they are often used with on/off input signals and hard on output devices. The are bein used with digital signals but are analogue devices. For a simple 3 level system I don't see any problem using opto isolators.
A "soft-Start" circuit can have a downside depending on the power on reset circuit being used. If a simple power on reset is used with a slowly rising power supply the reset may finsh before the supply is stable enough for correct operation. This can lead to unpredictable operation.
|Thread: endoscope / inspection camera|
You can buy a "USB Endoscope Camera" on ebay, Amazon etc for around £10 these connect to a android 'phone, tablet or a PC. They have built in lights and arv around 8 or 10mm in diameter. They can be had with 2 or 3 metres of cable.
I use one for all sorts includng looking inside engines
Edited By Robert Atkinson 2 on 01/10/2020 21:33:26
|Thread: Recycling Fire extinguisher pressure gauges|
These gauges are NOT suitable as they are not direct pressure gauges.They are contents gauges.
If you look closely at one with the pionter axis in the center of the dial you will see the pointer is attached to a coil of flat material. This is a bi-metallic temperature compensator. Thus the gauge indication stays the same as the pressure in the extinguisher rises and falls with changes in ambient temperature. This is obviously not a good thing for a boiler!
|Thread: Unusual Project|
The last F104 I saw (and sat in) had lost it's wings and was once flown by Chuck Yeager. North American Eagle. Unfortunatly even without wings it still crashed in August lst year killing it's driver, Jessie Combes.
On a happier note Burt Rutan designed and built an asymmetric aircraft
|Thread: Vacuum Pump Advice Please!|
I crossed with Rodgers post. His description is correct for the wet vacuum pumps like the speedi-vac and EV range. As the EB3A will also act as a compressor I'd expect it to have valve on inlet and outlet but I've never had one apart.
The EB3A is classed as a high vacuum but i't's relative. Specification seems to be 26" Hg / 133mB. So pretty good. Certainly good enough for a pendulum enclosure. It's not an oil free pump but is not wet/oil sealled. The wet ones have a "sump" cover over the pump block with a level glass. The Black plastic "cheese head" screw is normally the oil filler on Edwards pumps. Was the wadding wet with oil? If so it likely that is the oil filler.
Most likely issue is leacking or stuck valves. These will be poppet or reed (possibly combination) type.
|Thread: Customs payment is it a scam|
The correct way to report this (in the UK) is to simply forward the email to email@example.com
Action Fraud no longer take reports on attempted phishing. They are only intereted if you have acually lost money or goods.
|Thread: Cheap Oil for hardening|
Fuel in engine oil is a real problem. A particular case is modern diesels with particulate filters (DPF) some designs (Fiat, GM) inject diesel on the exhaust stroke to regenerate the DPF and some washes down the bore into the fuel. This can give a noticable increase in oil level.
It just goes to show you can't be sure about interference without measurement. Unless a VFD/inverter explictly states it has built in filters it will need external filters to bring emissions within limits.
|Thread: Creating negative pressure in flue?|
I concur with Dave.
Put the heater outside and run the hot water inside. If it's an air heater stll put it outside but get a carbon monoxide alarm as well. A relative of mine died from CO due to a modification to a heater. Not the way I wanted to inherit his watch making tools.
|Thread: Problems reading from a 3.5" floppy disc|
+1 for head cleaner. Another common issue is dried up lubricant on the helical "lead scew" that drives the head. A tiny drop of light oil can sort that out.
|Thread: Sievert blowtorch - regulators and hose failure devices|
The 305401 is also known as the HF3. It does incorporate a pressure reduction device. The limitaion is that it is not adjustable or well regulated (1.5- 4 Bar ). The fact hat it hs a POL fitting tells you it is not intended to be used with a regulator as regulators do not have POL output connectors. Sievert do sell HFs with adjustable regulators.
The HF-3 is sae to use as is. Most uses do not need the additional control of a regulator.
|Thread: Marking out blueing or pens?|
You mentioned "cold blue". This is totally different. it is used to produce the protective bluing of steel used on guns etc. While you could mark out through tthis I won't help with your problem because it won't work on oily material. And of course it only works on ferrous metals.
Edited By Robert Atkinson 2 on 17/09/2020 12:11:34
|Thread: Loc Tite|
You could go to the source
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