(EDITED: I changed the photo - the 1x1 rounds I made the engine struts with would not hold the weight of the engine sections together when extending out the back. My brother suggested using Technic Axles so the beams are single solid line pieces, and it should work really great, so the new plan uses the Axle pieces at the back. As always, click for bigger picture.)
(EDITED #2: New photo again! My brother just showed me a neat way of attaching bowed plates sideways to models to make smooth sloped sides on things, so I was able to remove the blocky stepped sides of the cockpit hull, and add sloping blocks to the sides - the whole front sections looks so much better now! Every alteration has made it look so much better! I think I'm done now, and can start working out what pieces to order from Pick A Brick on the Lego Store.)
I only recently found out that the Lego Store lets you buy individual bricks. I also found the instructions for the original Lego Y-Wing model that Lego created.
I worked out that a lot of Lego vehicles and ships are actually in rough similar scale to 30mm / 35mm star wars miniatures figures, after finding a list of all the Star Wars vehicles' lengths in meters.
I worked out that my lego model is around 40cm long!
Using the Lego Digital Designer program, I was able to recreate that original Y-Wing model - but only using blocks available to purchase individually from the Lego Store, so a number of alterations were made while designing this model.
I didn't like how the cockpit looked when made from default lego pieces, and I couldn't purchase the original Y-Wing's cockpit parts from Pick a Brick on the Lego Store, so I came up with the solution of buying a cockpit canopy window on Ebay for just $1.50.
So, other than the canopy, all the other parts are available individually and cheap from the Lego Store! I decided I wanted a red detail Y-Wing rather than Gold (all the official models are from Gold Squadron).
It also has a proper Astromech slot - a lego astromech can fit facing forwards, instead of plugging in sideways the way some of the kits do for some reason. So, it fits facing the right way in this plan. Once I've got the parts and have assembled it, I'll put a droid in it so you can see what I mean.
I haven't priced it yet to find out how much the basic lego brick parts would cost, to be able to assemble this model, but it's sure to be cheaper than an official lego set Y-Wing which is typically over $100 over here. I'm guessing I could build this Y-Wing model for around $50, and it's the same size as the full official Y-Wing model. (Not the collector edition, the standard edition) So it's probably around 35cm long (13" or 14"). $50 in Australia is about $30 or $35 USA dollars, so it's pretty cheap!
If it works out at that price, then I'm going to make my own basic-brick versions of all the ships at this scale instead of buying official kits. It will make great scenery for miniatures battles in places like docking bays or ramshackle rebel outposts, etc.
So the pic above is from Lego Digital Designer of my completed model design! I'm still unsure about the four beams sticking out at the back. I may use a different method of constructing those back parts of the engines, but for now, this is my idea.
The Lego Digital Designer also allows you to create illustrated instructions to build the models you make in it, but I'll probably cut and paste images from it's animated step-by-step, and create my own printable instruction book, which I'll turn into a PDF and upload to the blog if anyone wants to build my cheap version of a Y-Wing out of Lego. By selecting the colour of your own choice when buying the blocks with Pick A Brick on the Lego Store, you can make your own colour theme of your choice!