The beginning of a brand new bike.......

[Manley]

There was a post a while back of a 1/4 scale model mark4 in the Model Engineer magazine which im a subscriber of.  The model was nicely constructed but i felt a little bit pointless having most of the engine internals there and of the correct material but not actually working.  I was also particularly interested because i thought someone had gotten there before me! 
About a month before it was published i had started my own 1/2 scale 1937 Aero, of which i have the full size bike and bits of a spare engine.  This machine, 500cc in full size will be 62.5cc and i intend it to be fully working and as scale as possible.  Because of the original size, it should be quite possible to ride the bike when completed.  I have attached some photos of the display board which will be shown at the next Ascot Model Engineering Exhibition this weekend - worth going to by the way.  Not all of the bits are on display. 
some features of the engine components are as follows:

• Hardened and ground big ends to accept scale pattern individual roller bearing (gauge plate not En36)
• Case Hardened cam gears, followers and adjustable push rods
• Crank shaft built up and secured as per full size with correct pattern tab washers
• Working magneto under construction

So far, everything has been machined from solid, although patterns are currently being made for the front cover and lubricator sight feed. 
Im hoping that this will become a gold medal winning model as time progresses although uni will slow things down allot. 







Photos restored - Dave, 23rd July 2009

[Ian]

wow

[Doug]

The 1/4 scale postwar Douglas by Neville Heath started out with the intention of being a runner, hence all the internal bits. But along the way I suppose it became too difficult, or in the expediency of just seeing it done, compromises were made and it was finished off as non-operational.

Your 1/2 scale looks very well executed. Presumably you have the use of a CNC milling machine, going by the pocketing marks in the crankcase?

Cheers,

-Doug

 

[Manley]

Hey, i see my photo sever thing has taken down the old pics.  Well the project is continuing and i have a photo below of the front engine casing.  I have added a AA battery to show size.  I made a 3D model using the original as a guide - taking measurements and then tweaking it to look correct.  The model is then used to make code which is then used by my home coverted-to cnc machine.  Alot of polishing later to remove any chatter and maching marks will finish it.  It isnt finished but had to see what the experts thought.  Apologies for the pictures but its hard to focus with a small hand held. 



front

back - pump holes yet to be drilled for the working pump.


Ill post some photos of the flywheel soonish but below can be seen the center boss which is rivited to the clutch plate itself.  The sprocket will be pressed onto the step on the outer end.  I cant continue because im waiting on the needle roller bearing for the bore size.  It can then be fully parted off.  I realise that the cork holes should be rectangular but i hope you will forgive my round ones. 

Center boss

clutch plate

  all good fun 

 Edit: thanks dave

[Dave]

Hi Manley,

Thanks for keeping us updated on your interesting project. I kept a copy of the photos from your first post and have uploaded them to our server and restored the links.

Dave

[Manley]

Okay, im not sure how interested people are but ill post them up anyway. 

 The flywheel is now 95% complete.  All i have to do it skim the corks to run true and make the taper plug for the centre of the flywheel.  Ive tried to keep as scale as possible but ive used commercially available needle roller bearings as those individual rollers are a real pain in the bum.  Im also going to fit a keyway to the sliding inner sleeve that the clutch disc runs on because i noticed that my full size one had some serious scoring from the ends of the spring when it has obvious turned (from a previous owners lack of care).









The corks are now drying out ready to skim flat. 

Sorry for the number of pictures (not really) couldnt work out which ones to pop up.  Oh and there will be more.......(evil laugh)

  Rob 

[Manley]

Rather than post up here i have started to create a website.

If anyone is interested the address is:

http://sites.google.com/site/halfsizedouglasmotorcycle/

Rob.

[rpf94]

  I HEAR NEVILLE HEATH ALSO MAKES CLONE DOUGLAS 90 PLUS'S TO ORDER, OR AM I MISTAKEN?
RPF     

[Manley]

That looks really nice  

Hmmm, all the questions i have......

Where is it located? where did he get his tyres from? can i have it  

Oh and i've heavily updated and progressed if anyones interested

[rpf94]

the pictured 90 should have a folding kick starter and the tank is darker than the rest of the bike   

 

[Doug]

As soon at the photo gets embedded, I will move the previous reply to a new post, as it is starting to get off-subject.

-Doug
Site Moderator