What did you do today? (2013)

[Sub MandrelParticipant @submandrel]

I come from Barry and used to know St Athans well. It's a good mile from the coast. Rhoose/Glamorgan/Cardiff/Wales Airport has a runway that has a road and very little else between it and the cliffs.

Neil

[S.D.L.Participant @s-d-l]

Posted by John Stevenson on 15/04/2013 21:00:05:

Got a spare minute tonight so took the carriage handwheel off the scrap CVA and bored it out and drilled for a driving pin and fitted it to the new Bligeport.

Now got the best of both worlds, quick release lever or handwheel for deep work to save having to reset the lever.

How is the new machine compared with the old POS

Steve Larner

[Anonymous]

Posted by Stub Mandrel on 15/04/2013 21:27:03:

It's a good mile from the coast.

You'd be surprised how far the influence of a hill or cliff can spread. Having said that, the cliffs at St. Athan don't look that high, so I doubt they'd have too much influence at that distance. The airfield chart for St. Athan warns of wind shear in strong north-westerlies, not the southerlies you'd expect if the cliffs were involved.

It is pretty common to have similar effects at any hill top airfield, or where there are hills in the area, even if the airfield itself is in a valley. The effects can be fairly steady, or completely random with time. It can make for some pretty exciting approaches and landings, and I've had a few.

Regards,

Andrew

[WindyParticipant @windy30762]

Was not happy about the rougth dovetail bolts on my VMC so made some better suited for the stops.

Called at my motorbike friends workshop and he had part of a speedway engines fuel injection that had a stripped thread that had critical angles for the extended jet holder.

After a bit of head scratching made a simple mandril to align the angle then tapped to take an insert to replace the stripped thread.

I always fit inserts in aluminiium for bolts that are removed a lot.

Paul

[John Stevenson 1Participant @johnstevenson1]

Posted by S.D.L. on 15/04/2013 22:27:10:

How is the new machine compared with the old POS

Steve Larner

Difference is like night and day. Didn't realise just how loose the old POS was and having to make allowances for it. This new one is a lot beefier, 3Hp spindle against 1.5, box ways on knee and the whole knee probably weights as much as the old POS.

Power on all axis is nice as well.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Neville was an RAF pilot instructor so I doubt that his observations were incorrect . Difficult at this late date to analyse the situation accurately but I would guess that the Bernoulli explanation as provided by the RAF investigators was too simplistic .

All guesswork indeed but it is possible that a rolling vortex gets generated at the cliff edge and that this vortex gets some lift on it initially but then comes down again in vicinity of St.Athan .

There are apparently a few other airfields worldwide with unexpected ' down draft ' problems – almost all near mountain ranges or sea coasts .

[RJWParticipant @rjw]

The effects of windshear and any kind of turbulence generated vortices on airfields, especially the last stages of final approach are indeed random and, surprisingly fierce when least expecting it, but it is usual for pilots to give a warning over the radio when it is experienced!

Some vorticies are akin to those created when a jet aircraft takes off and lands, or rotor downwash similar to that when some idiot takes off in an egg whisk at 90 degrees to the final approach path when a landing aircraft is on very short final, I've aborted more than a few landings in those situations, but however they are experienced, they're not at all nice!

Doncaster airfield when it existed had wind shear issues on short final to runway 23, which was across Bawtry road, this was particularly bad on hot sunny days when the heat rising from the hot tarmac would create a very nasty shear almost immediately the road was crossed, you'd experience a sudden and vigorous thermal and then have it whipped away causing a rapid loss of airspeed even if the groundspeed hadn't changed, so higher than usual approaches were the norm on such days when warnings of them went out!

I was taught a salutary lesson in wind shear phenomena the first time I experienced it, and which nearly gave the goofers watching – including my instructor a heart attack, it was on my first solo, (1979) fortunately I got away with it, but it was a close call, not least because the aircraft I was handling (Grumman AA1) had particularly poor handling characterisitcs at low airspeed, and a vicious low speed characteristic of big sharp wing drops which tended to get very exciting when that 'envelope' was 'investigated' further – and to be well avoided close to the ground, which wing went down generally depended upon which way the balance ball was wagging in the turbulence, skittish and slippery little buggers they were and i loved 'em, but I treat them with utmost respect on final after that episode, plus very slick on rudder control, it stood me well in my professional career in later years – once learned never forgotten! !

The effect of being unable to climb after rotation was also experienced a few times on that same airfield, and wind direction over trees and buildings were responsible, but particularly affected one type of aircraft, Grumman AA5A & B's, which were the Traveller and Cheatah, neither the AA1 or AA5's were really suited to flying off or landing on short grass strips, but it's what we had available to rent!
The Grumman Traveller was the worst offender, with it's small elevator which lacked authority at low airspeed even on full power, so any sort of disturbance close to the ground could on occasions get pulses racing quite a bit when the far hedge got ever closer!

Not for nothing did those aircraft earn the subriquet 'Grumman Ground Grippers'

Compton Abbass airfield in Droset has a deep valley to one side of the runway, such that you can fly downwind and be below runway height, I did my initial instructor rating there, and my FIC instructor had a parculiar habit of either rolling the aircraft inverted or barrel rolling on the downwind leg without warning and disppearing from view of those in the radio room, which would raise an eyebrow, (he's at it again' ) but that valley created more than a few exciting moments when on crosswind limits – which were actually set lower than the aircraft were capable of when the wind was over that valley!
Strangely enough, although Bristol airport sits on and is surrounded by high ground, I can't say I ever experienced any shear or vortices other than the usual high wind buffetting!

John.

Edited By RJW on 16/04/2013 10:07:54

[Anonymous]

It looks like I've fixed the contactor on the repetition lathe. I made another 120 spacers last night, and this morning, with no problems. The contactor is pretty old, I'd guess early 1970s, but I don't think it has had much use. Certainly the people I bought the lathe from didn't use it regularly.

I don't doubt the observations of sink at St. Athan, more the official explanation. While the chart for St. Athan doesn't mention wind shear in a southerly, that for Cardiff does; presumably because it is that much closer to the cliffs.

While wind combined with cliffs/hills/ woods can generate considerable turbulence there are other phenomena that can also cause problems. Here are a couple of examples, which I've experienced first hand.

Barcelonnette, in the French Alps, is near the head of an E-W narrow closed valley, with a number of spurs sticking out into the mouth of the valley. The airfield is at about 3700' AMSL and the surrounding mountains are between 8000-10000'. The chart warns of strong sink on the approach in 20+ knot westerlies. When I landed there sure enough it was 1000ft/min down all the way round the circuit; strange because the general wind forecast was light and variable. Of course once on the ground I realised that there was a 25+ knot westerly. Why? Well, as the sun heats up the surrounding mountain slopes it triggers an anabatic wind. To replace the air in the valley, air is pulled in the from the mouth of the valley, to the west. As this flows over the spurs in the valley mouth it causes severe downdrafts over the airfield. The circuit and approach wasn't particularly rough, just a lot of sink.

Closer to home is Talgarth, in the Brecon Beacons National Park. The airfield lies in the shadow of the Black Mountains, to the east. In an easterly one might expect the circuit and approach to be rough due to the wind tumbling over the hills. However, if wave sets up it gets even more exciting. The wave primary is usually between the airfield and the Black Mountains, which means the down of the wave is just to the west of the airfield, with any wave rotor overhead. This gives a circuit that can be incredibly rough with heavy sink and strong lift, followed by a lot of heavy sink on the final approach. I've started a circuit at 2000 feet above the airfield and nearly didn't make it. Additional factors making it 'interesting' are that the main run is quite short at 440 yards, not much of an undershoot, no overshoot, and in a glider you only get one go at it.

Wave effects, and in particular rotor, have been responsible for my roughest flights over the years.

Regards,

Andrew

[John Stevenson 1Participant @johnstevenson1]

Any chance we can get this thread back on track and use the post that was started for aircraft topics ?

Edited By John Stevenson on 16/04/2013 12:52:21

[GaryMParticipant @garym]

What I did yesterday was finished four of these T-nuts as suggested in Harold Hall's book "Milling: A Complete Course". This was the first milling I've done. Wanted to try something simple before making a mess of the S50 castings. Might try some clamps next.

Gary

[Derek DroverParticipant @derekdrover32802]

Started banding the cladding for my Simplex boiler.

[Sub MandrelParticipant @submandrel]

DOH! moment…

A few days ago I used my boring head, and spent ages trying to find a pair of allen keys to fit the adjuster and the tool clamp screw. They weren't with the usual set and so I had to dig through various boxes and use a ball end one I keep for 'best'.

This moring I swapped over the BH for an ER25 collet chuck so I put the boring tool back in its wallet, yes, there is the pair of allen keys that fits the BH…

Neil

[chris stephensParticipant @chrisstephens63393]

Those d*mn workshop Gremlins having their hide and seek games, again! Perhaps more Government money should be spent on Gremlin research in order to find a proper humane disposal method.

chriStephens

[Boiler BriParticipant @boilerbri]

Yet another great day in North Wales and well worth the travel.

More work was done on the embankment away from the station area and one side of the banking was covered with turf cut from the station area. A very nice result.

The hired help builder finished one side of the wall rendering, so hopefully next week some paint will go, which will help blend the wall into the grass improving the view for the local residents.

We have no real signage up, (bad spelling) and it's quite amusing when passers by ask what we are making. The best for me was a lady who thought it was going to be a 'go kart track. Bless, i wonder how she thought we were going to balance the karts on a 9" block wall!!

The running trolley's will need modification to close the gaps of the trolleys and walls to make the anti tip work. Much discussion on this subject as to how we should do it?

So much to do yet, but the length of test track looked good, even having a loco trial up and down – pushing of course as i am sure the club will have an inaugural steam train when ready.

The three aspect lights also look good.

If you have spare time and energy why not pay a visit, Wednesdays or Saturdays, all are welcome.

New photo's in my albums.

Brian

[Bob PerkinsParticipant @bobperkins67044]

I managed to find a couple of hours to start to fit my Jan Ridders engine together. Still a bit to do though.

[Boiler BriParticipant @boilerbri]

Nice work Bob. How does the crank work at the bottom?

[Bob PerkinsParticipant @bobperkins67044]

Thanks. It's an open crank. Have a looks at Jan's website

**LINK**

[Peter G. ShawParticipant @peterg-shaw75338]

Now that it has warmed up somewhat, I am getting back into my garage, erm, workshop and continuing with the improvements to my Warco MiniMill.

So far I have had the table reground, made new X & Y gibstrips incorporating extra adjustments, ball bearings & pins to hold the gibs in place, cleaned up the slide faces on the saddle (originally created with an angle grinder!) and reassembled. It's a lot smoother now. The only problem is that the X leadscrew nut can't be fastened in place as it causes binding. Must try and look into that somehow – only trouble is that it is way out of sight in the innards.

Started looking at the Z (vertical) axis in an attempt to make the fine feed smoother. So far it looks as if the fastening screws for the worm gear housing don't line up correctly, the holes for the wormwheel are far too large, there was some dirt at the bottom of the worm housing which prevented it from sitting correctly hence its clamp plate simply jammed it up solid necessitaing a pair of washers to act as spacers on a temporary basis. Anyway, I've decided to see about making a new housing with some tighter & more accurate fitting. I'm going to try aluminium first and if that seems ok, then have a go in steel. You see, I have plenty scrap aluminium 13mm thick by 200mm wide, so the first thing has been to cut & glue two pieces together to make a block 25mm thick by 56mm x 64mm. Or thereabouts. Yet again discovered the B&D Scorpion despite having a metal cutting blade does not really like cutting even soft aluminium. And the vibration is terrible. Eventually used a 5" angle grinder with a metal cutting blade. Much better, much easier, even if it did keep objecting to being overloaded. Also attempting to draw the original on CAD, not easy given its shape and general roughness.

Bath time now, then read a book followed by shuteye, I hope! But after having had to open the window during the last two nights due to overheating (and my heating has been off for a long, long time) I do wonder about how good a night's sleep I will get.

Ah, well, the trials & tribulations of life.

Peter G. Shaw

[Boiler BriParticipant @boilerbri]

Ah I see, i could not make out the crank in the photo, Eyes tired at this time of day.

bri

[Boiler BriParticipant @boilerbri]

HaHa, i have just watched his video. What an engineer he is. I just love his funnel!!! LOL.

He must have spent hours on the model of which i have to credit him for but he could have made a funnel.

Bri

[John Stevenson 1Participant @johnstevenson1]

Much gnashing of teeth today, 1,340 to be exact.

Decided to do a batch of the Myford 33 / 34 gears for metric screwcutting on the gearbox machines.

Gert was giving me grief about no stock.

John S.

[Sub MandrelParticipant @submandrel]

Hi John,

Wow! Even I don't normally take that many tries before I get it right!

You do know you've stamped the numbers the wrong way round?

<ducks>

Neil

[Ian S CParticipant @iansc]

I'v been using on occasions a 500W flood light, and getting sick of it eating its way through numerous tubes, so I went into town and bought a 10W mains LED flood light yesterday, it goes well in the workshop, not quite as bright, the old one was a bit too much. But then while waiting for the bus home I found a place selling bike tiers for a dollar each, and bike computors three dollars each, bought two of those, one for the bike, and one to play with as a tacho perhaps, I'll have to study it a bit. Ian S C

[AndyfParticipant @andyf]

Ian, if the bike computer has no RPM function, set it to read out in kph rather than mph, and make it think it is reading from a bike wheel of 1667mm circumference (530mm diameter). Then, a readout of 34.5 kph represents 345 rpm. Some of them only go up to 99.9kph, but others go up to 199.9kph (equivalent to 999 or 1999rpm). Either would be pretty speedy on a pushbike! Because it only gets one blip per revolution, the display can be slow to settle. Usually, the sensor is a tiny reed switch encapsulated in plastic (rather than a Hall effect switch) and can be a bit fragile.

Andy

[Ian S CParticipant @iansc]

Thanks for that Andy, I'm sure I'd have worked it out eventually, but that speeds up the process. The normal price of the thing is $NZ16, and even that seems cheap, but the Chinese bike tiers are normally $NZ12 or more, perhaps its because the Chinese are taking to cars these days and they have over production. Ian S C

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