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RogerH

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Posts posted by RogerH

  1. 1 hour ago, Ian Smith said:

    A double whammy with the air pressure on aircraft tyres, I'd guess. Assuming the wheel is fully pumped up, lets say, a nominal 10 bar (other pressures are available) then every 1 metre in height gain, should reduce the pressure by 0.1 bar. So, let's assume, therefore, that a height of 100 metres will reduce the nominal pressure to zero.* The tyre  'should' expand, as the air within is acting on the rarefied upper atmosphere. Although I've never worked on aircraft (apart from Airfix kits), the physics remains the same. The air (or gas) will try to escape to atmosphere.  I should imagine an aircraft taking off, fully A1, and landing with an under-inflated tyre. It's gotta go somewhere!

     

     

    Ian. 

    Hi Ian, 

    you have left some noughts off.

    At 100Mtr the airpressure is 990mB - a reduction of 0.01mB/100Mtr.

    It is still a lot when you consider aircraft fy at 10Km   

    Have seen an aircraft tyre and Wheel close. These are not delicate things.

     

    oger

  2. 1 hour ago, Ian Smith said:

     

    .  If your alloy wheel has a slow let down, then porosity in the casting might be at fault. 

    At British Airways I was asked to investigate an aircraft nose wheel as it kept letting the air out.

    I took an X-ray and was surprised to see what looked like a giant 'Aero' bar.  Never seen that before

     

    Roge

  3. 41 minutes ago, Iain T said:

    I take it a used wanner is as good if not better than a new nameless version? I like the idea of reusing old stuff instead of buying new from China! 

    Hi Iain,

    the Wanner is the RollsRoyce of grease guns.  Even if it did not work it would still be better than the rest.

    You'll never regret having a Wanner.

     

    Roger

  4. Hi Dave ,

     if you were using solid rivets then the material thickness to rivet length ratio is important.

    Pop rivets this ratio is less important as the rivet is not truly a structural fastener.

    However if you look at Pete's link then you may see that the rivet length is material  T + the rivet shank O/D. 

    EG using a 3.2 diameter rivet  with  4mm of material then go for a 7mm long rivet or the next size up.

    You don't want to use a 20mm long rivet in 4mm of material.

     

    Roger

  5. Hi Brian,

    have you had a look at the Moss webCat  Bezels   On the Spitfire Have a look also at the TR4/4A bezels.

    The problem is that even within Triumph there are very many different threads/sizes used.

    I have made a set for my 4A and now have the taps & dies.

    If you can supply the sizes you need I may be able to help.

    Roger

  6. Why why why go aluminium.

    The ONLY advantage is a slight weight saving. And unless you are racing the nuts off the car you do not need it.

    Aluminium does not cool as well as a decent original Copper rad. So if you need cooling why buy Aluminium.

    Cheap is the wrong reason to buy.  Also, Why support the Chinese.

    Roger

    • Like 1
  7. Hi Folks,

    I am coming near to the end of my TR4 rebuild.

    The last few days I have been driving it to get the carburation sorted but found the rear brakes seizing on.

    Today I spent 3 or 4 hours investigating the rear near side. What I found was was bl**dy annoying.

    About 5 years ago during the rebuild I replaced the near side cylinder as it was leaking (I should have just replaced the seals). A ywar later I had to replace the offside also. 

    Today I found that the cylinder was completely seized against the back plate.  For the brakes to work correctly the cylinder needs to move freely back and forth. 

    The cause ( I suspect) is that the cylinder has a groove down each side into which the captive plates sit. This groove is too narrow.

    Tomorrow I shall open the groove by apprx 0.020" - hopefully the cylinder will then float into a mid position and release the brakes.

    Why can't repro parts work first time.

     

    Roger

  8. 35 minutes ago, daverclasper said:

    With the acid types, is the idea to remove the rust/rust pits, and neutralize to hold the rust coming back, or just make it temporally look better?.  

    Hi Dave,

     once you have rust coming through the Chrome you are looking at the end of the Chrome finish.

    The chrome particles sit on the surface of the parent metal like little islands and so moisture will easily get in and cause rust (which comes out)

    So, the platers put down a layer of Copper & Nickel. These are solid layers and should last many many years.

    However if rust appears then the Copper/Nickel has been punctured and can't be rebuilt without complete removal and re-plating.

    But, panic ye not!!   You can remove the surface rust will stuff like DeOxC (this may be Citric  or Oxalic acid based).

    When the surface is spotless apply a serious wax polish AND keep it polished.

     

    Roger

    • Like 1
  9. Some interesting comments.

    Here in Hayes, near Heathrow, parking outside will get the car covered in all sorts of muck and the paint will suffer.

    The cover shown by JagNut is very kind to the paint work.   Make sure it is reasonably anchored down to reduce flapping.

    Being breathable, you can put it on a wet car. I have done it many times with no issues and the car is always dry when I take it off.

    Roger

  10. Hi MIke,

    I have a cover with what looks like the same material. It is perfect for outside use - all year.  Should last 3 or 4 years.

    Be careful it will puncture easily on sharp  pointy things like aerials.

    If it fits the shape of your car all the better.

     

    Roger

  11. About 5 years ago it was found that a big UK supplier had a batch of badly hardened layshafts for the TR6 gear box - not hard enough.

    This was brought to their attention at the time in the shop - all the stock Apprx 50 shafts) were duff.

    What they didn;t do was contact all the trade suppliers they had sold to and their customers - bad move !!

     

    Roll on to 2019  and the TRR PQI receive a query that a recently rebuilt GB had destroyed itself and when opened up the culprit was the soft layshaft.

    The GB had only run about 1000 miles.  The PQI spoke to the complainants supplier and they said it wasn;t their Problem (perhaps TRading Standards would disagree)

    as they got it from the first big supplier.

    After about a month or so of lots of emails (each blaming the other) the first big supplier took the GB & OD into their workshop and rebuilt it FOC.

    The first big supplier went to the expense of buying a half decent hardness tester 'Rockwell C' and now check all their shafts.

    I'm not suggesting that the TSSC should form their own PQI (Parts Quality Initiative)    -    but it ain't 'arf effective. 

     

    Roger

     

     

  12. 1 hour ago, RichardS said:

    Thanks Roger

    I don't have a reamer but if the new one that is now being sent is as tight as the ruined one, I will definitely find a way to increase the internal diameter before fitting it.

    Richard

    Hi Richard,

    if your bushes are tight and you want to borrow mine I will send it to you.  I will be passing through Evesham on Friday and Sunday and will be at the TRR/TSSC/MG bash at Malvern

     

    Roger

  13. 15 hours ago, Sparky_Spit said:

    There used to be a DIY kit available from Maplin Electronics that was easy to put together and only cost about £15.  I built one for my Spitfire and it works very well.

    As you may know, Maplins closed some time ago but there may be a source of the same kits elsewhere?

    EDIT.....   Looks like they are still trading online.  See Maplin - K2599 Intermittent Wiper Controller - Special Savings Today at Maplin Direct with UK Direct Sale 

    Bargain at £12.99

    That kit works well. You can also put the timer pot on a fly lead so that the circuit can be hidden away somewhere convenient.

    I wouldn't go near the 'smart screen' unit. Too many folk have said how iffy they are.

     

    Roger

  14. Hi Folks,

    Copper is odd stuff.

    To anneal - heat to cherry red then quench and stir in water - the more rapid the better.  This is unlike Ferrous metals

    To harden - not usually done as after it is annealed and then worked upon it will harden (it is called 'Work hardening')

                       Be careful once work hardening has set in the copper may well crack if you try to work it more. Re-anneal if necessary.

    Hi Dave  - I can't visualise what you have is it like the pic below  4th line down.  Are you sure it is copper or brass - if so it will solder easily and will no further heat treatment.

                   The pic below looks like steel but I'm not sure. If it is steel then this could easily be soldered of silver soldered (a little stronger)

     

    https://www.google.com/search?source=univ&tbm=isch&q=Triumph+Vitesse+petrol+cap&sa=X&ved=2ahUKEwjyod2-5fPxAhXaQUEAHQB1AQsQjJkEegQIDBAC&biw=1517&bih=730#imgrc=ig81RlkNyCsvbM

     

    Roger

  15. 13 hours ago, johny said:

    Ive just replaced the valves in the original AC fuel pump from my Mk1 Vit. Not a bad job and the difference in the pump operation is night and day. I had to file away the 6 stamp marks that lock in each valve (easy as its alloy) and one then came out very easily as there was access to its reverse side. The other however is harder to get out with levering the only way to do it which of course destroys the valve and it youre not careful marks the alloy body.... It eventually shifted and theres even a paper gasket under each valve! I removed these as its overkill because the new valves tap in very snuggly and, for the same reason, I didnt make new punch marks to hold them in either.

    Job done!

    You MUST retain the valves somehow.

    I have a repro AC pump on my TR4A and after quite a few miles a valve dropped out - the car stopped.

    Easy enough to pop back in but it came out again after only a 1000 miles or so.

    I resorted to fitting a plate over the valves held in with an M3 screw,

    The push fit will not withstand the continuous vibration.

    Roger

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