Small amount of progress on the 08 this week, added some small angle with rivets around the fuel tank bases's only to run into another more difficult problem to solve. The half etch for the inspection hatch is too low, the angled strap only just fits in and leaves no gap like the 1:1. Not sure what to do, too late to add a thin shim (5 thou?) to fill the half etch and smooth effectively (should of been done on the flat before folding up) so may just have to live with it, or add the inspection hatch at the correct height and fill the remaining half etch with thin filler or something.
In other news collected some sundries from Kettering yesterday to allow me to do the CSB for the chassis, quick calculation and soldered the relevant parts to chassis and horn blocks, I used 1.0mm ID brass tube and 25SWG for the required 1mm deflection, 25SWG is 0.51mm dia so there's some slop in there when the loco is picked up but overall it all works fine and dandy. The 25SWG gives a lot of (relative) travel and makes for a very soft suspension which led to some observations (below) but these may actually work quite well in operation and make for a lively and animated motion, less wooden and more prototypical?
Next I ballasted up the loco to the intended weight, around 1000g and it sat nice and level all around but I noted some things that may need changing.
I'd read somewhere that the intermediate axle should be sprung less, yet no one seems to be prepared to put pen to paper as to how exactly much. So I opted to go with 34.28 - 31.44 - 34.28% however this seems to still place a lot of load on the centre axle, so much that it'll probably have a tendency to nose when running, now real 08's nose and swing about like crazy so it might be a desirable trait to keep but may have to decrease the intermediate % a little to 36 - 28 - 36% to help reduce the model to nose. It didn't help having all the test weight way up high which gave the model a very high metacentric height, that'll have to come down a lot and may help the previous observations.
Getting the weight in is going to be a problem, the motor is going to take up a bit of space and filling the rest of the bonnet is going to have negative effects and the nose will drop considerably. The problem is the wheel base, it's not in the middle of the loco, there's a greater overhang to the rear, obviously the cab cannot be filled with weight so suspect a large lump of lead under the floor will be required to balance the loco at the aft end.
What's next, well the compressor box needs to go in and the exhauster box lid, also need to add the same riveted angled support around the front of the radiator base where it joins the foot plate and then work out some way to make the new bonnet roof, possibly detachable for the build to assist getting the weight in.
There's also the boxed BCV sitting glowering at me, especially as I said it could come out today as a distraction and progress as the first piece of freight stock I will have LOL.
, I think Steph uses the same adhesive for his coach sides etc and the critical part to the equation is making sure that each surface has a key for the adhesive to bond too.
