Sunday, 28 June 2015

Wakefield Covered

This weekend I covered the Wakefield with tissue and sprayed it with water for the initial tissue shrink.   I had to re-do a couple of panels because they weren't quite perfect, so it took a little longer than I intended.   I also had to be careful as I had just 3 sheets of white tissue and this was only just enough to cover the plane.

Next step is to clean up the edges and then apply two coats 50/50 mix of cellulose thinners and cellulose dope to do the final tissue shrink.

Covering complete, with 12" ruler to illustrate the scale.

Wings placed on fuselage, note tail fins not attached yet

Sunday, 14 June 2015

Saturday, 13 June 2015

Constructing adjustable undercarriage

I've been procrastinating on finishing my wakefield because I was struggling with the construction of the undercarriage.   The wire provided with the kit was tricky to bend and I was avoiding starting it.   Instead of fixing the undercarriage to the fuselage, I instead chose to slide the wire into brass tubing inset into the fuselage.   I added two height settings to allow me to tweak the centre of gravity.

The tubing allows me to remove the undercarriage for easy transportation and storage.  The fit is snug enough to ensure the wire frame does not pop out, but I may also hold the left and right sides in place using a rubber band if required.

Low setting, undercarriage is pushed further forward

Upper setting, undercarriage is set further back

Showing high and low rear settings
The Y shaped undercarriage is joined using some very thin copper wire wound around the joint and then glued with Evo-Stik rapid setting glue.

Saturday, 11 April 2015

Centre for Computing History, Cambridge

Recently I took the family to the Centre for Computing History during a short break in Cambridge.  The centre is packed with a plethora of machines from the 1950s onwards and has an excellent collection of 8 bit micros from the 1980s.

A DEC V220 terminal. I used one of these in 1988 when working on FORTRAN signal processing analysis software on PDP 11/750s (running RSX-11M-Plus) and MicroVaxes (running VAX VMS)

A 10MB DEC RL02 Disc Storage Unit.

A Commodore PET. I hacked on these in 1985 at school. I was able to write a program to poke characters to the screen starting from address 32768.

An Apple III.

Silicon Graphics Kit.

An SGI Indy Pizza Box. Nice bit of 100Mz MIPS hardware running IRIX.

The ill fated Atari Jaguar. Jeff Minter's Tempest 2000 was quite stunning on this box.

Another Commodore PET, this is the 8032-SK edition.

The "Luggable" Commodore SX-64.  A C64 with a hardly readable in-built monitor and 1541 floppy disk drive. At 10.5 Kg it was not really that portable.

There were 3 bigtraks in the museum. All still programmable and could be played with.

A Commodore 64 and a C2N tape deck. The C64 sold over 30 million units; it was my first computer and I learnt 6502 programming and various low level tricks with the VIC II video chip.

The Commodore Plus/4.  I showed my kids that it had a in-build machine code monitor and one could easily hack up simple 6502 code with this tool. Pity this machine had less capable graphics than the C64, otherwise it would have been quite a nice machine.

An Apple Newton. Ahead if its time.

My son playing a game on an Apple ][.  I used the Apple ][ for my A level computing, it was a versatile machine and call -151 was required to get access to the machine code monitor.

A Commodore VIC 20.  This was running Attack of the Mutant Camels by Jeff Minter.

The Commodore Amiga CD 32 games console. I'd prefer a real Amiga any day.

There was a classroom of the "1980s" filled with BBC B and BBC Archimedes micros. The user guides were available so that one could write some code on these.  The BBC Bs were sturdy machines and very capable. The BASIC was excellent and the 2 pass in-build 6502 assembler was a great tool.  At £400 a pop, they were pricey compared to the £200 Commodore 64.

Monday, 16 March 2015

Sparrowhawk chuck glider

After an earlier discussion about designing a balsa aeroplane my son later in the day presented me with his design of a chuck glider.  We had to see if it could easily be made and if it would fly.

Out of some 1/16" sheet balsa scraps I cut some 1/16" x 1/16", 1/16" x 3/16" strips for wing ribs and leading and trailing edges.  I cut 4 lengths of 1/16" x 1/4" x 10cm strips that we laminated to make a rigid stick fuselage.   We used some scrap tissue for wing and tail covering and by the end of the weekend we had a chuck glider that just needed a small amount of Blu-Tak for a nose weight and it flew perfectly!

I tidied up plans and they are available below:

Fuselage: 10" long, 4 laminates of 1/4" x 1/16th sheet.
Tail fin: 1.5" high, 1.5" long from 3/16" x 1/16th sheet.
Tail wing: 2" wingspan, 1" triangles from 3/16" x 1/16th sheet.
Wings: 5" wingspan, 1 3/8" wings from 3/16" x 1/16th sheet (leading + trailing edges) and 1/16" x 1/16" sheet for the ribs and diagonals.

Sunday, 8 March 2015

Wakefield fuselage nearing completion.

I found a few more spare hours during February to start the construction of the Wakefield fuselage.  The main construction phase is now complete, I just need to finish off the wire landing gear and the rubber end mounting fixtures.

The kit supplied enough balsa for the fuselage without the diagonal bracing, so I used some spare 1/8" sheet to cut some balsa strip and add the bracing in as additional strengtheners as suggested by the original plans.

The fuselage was relatively easy to build, but I did have to rig up a few jigs to ensure I got a perfectly square and rigid box frame.

Monday, 2 February 2015

45" Wakefield wings almost finished

Over the weekend I completed the final elliptical wingtip and tailplane and assembled the 45" wings to the EasyBuild Wakefield.

I need to add in some central strengtheners, do some more sanding and add in few triangular fillets, but the hard part is now complete.  The angle of the photo made the ribs look a bit distorted for some reason, I can assure you that they are set correctly.   The wingtips sport a 4" dihedral, but for a 12-13" wingtip isn't too severe as it first sounds.

I now need to find a large board to start constructing the rather long fuselage... onwards and upwards!

Sunday, 1 February 2015

Accurately cutting balsa strip

Cutting balsa sheet by hand using a metal ruler and a sharp modelling knife has always proven to be tricky to get the perfect cut of balsa strip.  One of the presents I received at Christmas was this simple and yet very effective balsa stripper.  The width of the cut can be easily and accurately adjusted by turning the dial.  The knife blade can be adjusted to the required depth and cutting angle to get the perfect cut.

Not bad for under £10 for the cutter including postage. I wonder why I never got around to acquiring one earlier..