SE5a CONSTRUCTION BEGINNING TO . . .

[Guest]

I envy your skill and paitence Grahame.:bravo:

[Greyhead]

It’s been a tedious, that’s not to say boring, few days but I now have the 60 radiator slats I need. The slats, 30 for each radiator, have to be accurately positioned so are held in a jig whilst being soldered to the sidebars; the pins keep all the slats at the same angle.





The soldered joints are tidied up with the Dremmel then the lot epoxied to the frame, which is made from litho plate; the railway track pins will be used to attach the finished frame to the brackets that hold the unit to the radiator.

[Guest]

Brilliant work Grahame!

It was really worth taking the extra effort to make those individual slats - they look great!

[Greyhead]

Before fixing the radiator slats to the fuselage all that needed to be done was to solder the brackets to the track pins; a simple job or so I thought!





This is where I hit another problem; my “new” supply of track pins won’t solder, they must be made from a different metal. Of course for their intended use in model railways it doesn’t matter whether or not they’re solderable so I can’t really complain.


Anyway it was quite a job removing them without damaging the litho plate so it’s taken all day just to get one side to this stage; I should have checked before gluing them in place but I never gave it thought!

[Greyhead]

After much delay my 5” Williams Brothers Vintage wheels have arrived; although they are not in their catalogue DB Sport & Scale ordered them from America especially for me at no extra cost, excellent service!





In the past I’ve used Williams Brothers wheels and although they are quite expensive I considered them to be good “value for money” because of the quality and detail of the moulding. As I’m sure you know they recently went out of business, someone else now produces the wheels, and I have to say I’m rather disappointed with the result.


There has been some damage to the mould and because the surface is textured to represent the fabric covering, it will be difficult to remove the blemish without it being obvious. Also the valve detail is poor; it looks as if this is a produced by a separate insert in the mould, perhaps the original has got lost and been replaced with an inferior version.


My idea at the moment is to use Solartex to make a cover, if it works it may well look even better than an “original” Williams Brothers wheel but it’s a job I could have done without.


On to happier things!! Having sorted the method, the second radiator frame went a lot easier than the first and although it’s been quite a fiddly sort of job I’m really pleased with the end result.





When everything’s painted PC10 except for the slats themselves they should make quite a “feature” on the front end.

[Greyhead]

I’ve decided that something has to be done with the wheels. One thing that everybody seems to complain about with Williams Brothers wheels is the weight; they are heavy but in the past I’ve been prepared to put up with it because of the quality. Having “attacked” the wheels it’s obvious why they’re so heavy, the plastic mouldings are a good 3mm thick, so removing ½ the back is a considerable weight saving exercise in it’s own right.


I started with the back face for a couple of reasons; firstly, if it turned out to be a complete disaster any repairs would be less on show and secondly it lets me see the internal structure. In fact there is very little internally, the two sides are simply joined at the hub and the outer rim so there will be no problem drilling the “valve hole”.





A word of caution; if anybody thinks this is a good idea and is thinking of doing the same I’d wait a while, I’ve never tried this before and could well end up with £20.50 worth of rubbish so I’d wait and see what the end result actually is!

[Greyhead]

The front face of the wheels has the area between the spokes where the valve hole will be removed, I also reduced the length of the “spokes” as I prefer the look of the wheels where only the first section of the spokes shows through the fabric covering. Before applying the Solartex the surface is wiped over with thinners to remove any residue of mould release agent and given a coat of Clearcoat.


First I tried to cover in one piece, shrinking the outer edge to make the “cone” shape; there was enough shrinkage to take up the correct shape but it proved impossible to get it even. I eventually cut the disc of Solartex along a radius opposite the valve hole, bonded it around the outer edge and cut off the excess then worked towards the centre using the iron





It took me 4 attempts before I got the method right but the finished wheels look just right; not perfect, the “faults” are now as they should be, small creases in the fabric (not obvious moulding faults). The valve hole doesn’t look round in the photo but that’s just the matt black paint, which I’ve painted the insides of the wheels with.

[Guest]

The wheels look much better with the covering stretched over the spokes in the centre of the wheel but not at the edges, gives a much better scale look.

How were those original wheel covers attached to the aircraft? I noticed on the wheel there are some obviously modelled on protruberances around the rim, were these stitches or some kind of eyelet and a wire fastener or something?

The only reference I could find was here:

http://www.hawker-restorations-ltd.co.uk/Media/Avro/8.html

Palmer Detachable Wheel Shield from a 504

[wonwinglo]

Yes the covers were laced with beeswax cord binding,mud was a problem especially operating from rough grass fields,the wheels and bearings needed constant attention and the covers became very grubby and worn looking.

Also the springing from these wheels was poor due to the narrow rims and Palmer tyres ,the rubber bungee lashings was the only suspension.

[Greyhead]

Alan


There are various methods of lacing the wheel covers; the one used on the Williams Brothers wheels is a kind of zig-zag stitch similar to the fuselage stitching, there was also a “running stitch” which follows the diameter and probably several more methods that I don’t know about! There are also the ones that apparently don’t have any lacing, at least none that shows, whether or not they use clips I’ve no idea; as far as I’m aware this method was used for the SE5a, on the C1096 restoration there is no rim showing at all.


Whether the spokes show only near the hub or right to the rim depends on the position of lacing and the way the spokes are arranged, if the wheels have the spokes arranged radially then they are more likely to show right to the rim, if they are crossed over, like bicycle wheels, more likely to show just near the hub but it’s really a combination of the two things.


Grahame


The valves are made from lengths of 2mm brass tube with the ends threaded.





The valves are heated up then “melted” into the rims so the ends show through the valve holes; just the back to cover now, that’ll be no problem as they are virtually flat discs.

[Greyhead]

When I went the next morning to continue with the wheels I found that the covering had slackened off. I thought this was probably caused by using too much heat to shrink the Solartex; the correct method for complex curves is to apply a little heat, which makes the Solartex pliable, do most of the forming by actually stretching not shrinking, then use a bit more heat for final shrinking, if you use too much heat, the Solartex shrinks OK but after a while it “relaxes”.

With the tyre in place I couldn’t pull the Solartex around the rim so I’d had to use a lot of shrinkage to get the fabric taut; I first made a jig so that I could pre-form the Solartex into a conical shape by stretching, stick it to the wheel then use heat for the final shrinking. The amount of heat needed to get the required shrinkage didn’t seem excessive although I still couldn’t get the Solartex onto the wheel really tight but after a few hours the Solartex was loose again.

For the next attempt I was going to have to remove the tyre, no easy feat with Williams Brothers wheels as they have a moulded lip that presses into a slot, I had to cut off a section of the lip to start with then pull extremely hard to remove the tyre. With the tyre removed I could stretch the Solartex around the rim and as an added bonus there was all the inside of the rim to attach the Solartex to so no chance of the bonding failing, the fabric was tightened using very little heat. After covering the back and struggling to get the tyre back on I went to bed a happy bunny!

The next morning I wasn’t so happy; the covering was loose again, even the back which is virtually a flat disc; this called for drastic action! I tightened the Solartex again with the heat gun, poured some cyano on, spread it around evenly and gave it a blast of activator. I repeated this 3 times, the covering now feels quite solid and it appears to be remaining taut, but I’m not “counting any chickens” just yet!

With the back going slack all I can think of is that it must be some reaction between the covering and the plastic that the wheels are made of causing the Solartex to “relax”, has any one else had this problem?

[Greyhead]

Well the covering’s still tight this morning so hopefully that’s that problem solved, I just wish I knew what caused it in the first place!

[Greyhead]

The wheels have a plastic washer glued to both sides of the hub to protect the Solartex and to make the wheel attachment look more authentic the piano wire axle has brass tube sleeves added. To ensure a slop free fit I cut “teeth” in the end of the tube using the Dremmel and a cutting disc then reamed out the wheel holes with it.





The sleeves have a hole drilled for a split pin then a washer is soldered to form a “back stop”. A useful tip is to use a wooden spring type clothes peg to hold the washer square on the tube whilst soldering.





The sleeves are then glued to the piano wire axle with epoxy. The completed axle is held in position on the undercarriage with “O rings” to provide a certain degree of springing.





As you can see the spoke detail is very subtle just as per the full size, on most commercial wheels it is usually a bit “over done”.





I’ve had fellow modellers ask me why I don’t solder the tubes to the axle, well the simple answer is “It’s easier to use epoxy” and all I can say is that I’ve not lost a wheel yet, at least not one that was attached using this method!

[wonwinglo]

Solartex can be funny stuff at times,you could have had a slightly faulty batch it is possible,there is a built in shrinkage memory,although I have never used a themometer ever on any heat shrink material apparently you should do so according to Mr Hardiman its inventor,it probably is possible to over-stretch the material ? but who is bothered as your wheels look just like they did in WW.1,ie wrinkled slightly through constant canvas removal.

[Greyhead]

I’ve used the particular batch of Solartex before without any problems; I used “old stock” because I wanted to make sure that the spoke detail was correct, with natural Solartex being translucent it’s difficult to know exactly how it will look when it’s been painted. When I formed it into a conical shape on the jig I left it for a couple of hours to see if it would slacken off but it didn’t, until I attached it to the wheel that is, when it was obvious within a few minutes that it wasn’t going to be any good!

I’ve got a thermometer, which I used to check the temperature of the iron as per the instructions supplied with the Solartex, and marked my variable power supply accordingly but unfortunately I had to use a heat gun for the wheels, which is either on or off, having said that I’ve never had any problems using it in the past.