The place to raise issues, ask questions, swap ideas and discuss anything related to aircraft engineering, maintenance and building.
NB Any opinions expressed in this forum are not necessarily those of LAA Engineering
I was taught from an early age never to put grip a steering wheel with the thumbs inside! This was at the time because I was driving old type tractors. The wheels could easily catch on ruts and spin the steering wheel, breaking said thumbs!
It's a habit that has stuck, and I still never have my thumbs inside the wheel of any vehicle I drive. I can see now that it would be a good habit for drivers in general to adopt .... ouch!
The "Fergies" were very good at thumb strains. Starting engines with a starting handle was another - I broke my wrist starting an old pre 1940 single cylinder Lister diesel engine when the decompression lever was mover over.
I was taught from an early age never to put grip a steering wheel with the thumbs inside! This was at the time because I was driving old type tractors. The wheels could easily catch on ruts and spin the steering wheel, breaking said thumbs!
It's a habit that has stuck, and I still never have my thumbs inside the wheel of any vehicle I drive. I can see now that it would be a good habit for drivers in general to adopt .... ouch!
Ivan
Was told the same by a rally driver and it stuck with me ever since
cardiffrob wrote:When you think about it, the LAA fleet are a health 'n' safety hazard zone. Spinning props, fuel lines, GRP catalysts, rivets, paint fumes, splinters.
If GA were 'invented' today it would be banned immediately as way too dangerous a pastime.
Mind you, so would motorcycling and driving cars, come to that!
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.
The method I have always used to scarf plywood is the use a sharp small block plane to get the scarf down close to what I want, but not cut into the final lamination as it will split away. Then I finish with a sanding disc in an angle grinder followed by sandpaper wrapped around a block. This is how I have always done them and its eassy after a bit of practice. Its best to clamp or staple it to a piece of wood as a backing to give some support .
My angle grinder is battery powered so isnt too fierce but have used a standard electric one no problems.the resin boded sanding discs seem to be the best.
Practice on some scrap first and you will soon get the hang of it. Best thing with this method is you can cut scarfs on curved surfaces just as easy...for example putting the top decking ply on a fuselage in sections or on a wing leading edge
It was interesting to see on the Pietenpol site that they show a scarf angle of 8:1 wheras I was always under the impression that for aeroplane use it was 12:1 for Plywood, and thats what I have always done
I have always used 15:1 for Spruce sections and 12:1 for the plywood which is what I was told when I first started in aeroplanes, and 12 is adequate for plywood as that final outer lamination is very very thin even at 12.
Interestingly on the original DH Comet fuselage drawings the Spruce and plywood is shown scarfed at 10:1 !
If its good enough for DH Iguess its good enough for us. I better recheck the PFA handbook to see if I have not read it properly and quoted the spruce values.
No time now just off to the Airport.
