Author Topic: Bentley Br2 step-by-step building  (Read 803 times)

Offline taurusmodels

  • Moderator
  • Full Member
  • *****
  • Posts: 235
Bentley Br2 step-by-step building
« on: August 30, 2015, 06:16:20 AM »
OK, as I told, I'm presenting step-by-step building of a Bentley. This tread will be created simultaneously with detailed instruction.

Let
s start :)

First step is cutting of the crankcase (part 14) from the casting block. For this purpose one can use razor saw, and next micro milling machine to remove any excess of casting block.



The same you should do with cylinders (part 1).

.

Having ready crank case and cylinders, attach cylinders to crankcase with the use of two-component glue. It is only one position possible, nevertheless you should care about correct alignment of each cylinder. It's extremely important for overall engine's geometry.



Having cylinders attached to crank case, you should mount cylinders fasteners (part 3). Cut if of from the casting blocks and attach in the correct places, as in the picture below.

.

Fasteners are little longer then cylinders, so now you should cut it of at the correct length. I'm using for this very sharp modelling knife, and toothpick for keeping the element.

.

Now it's time for mounting the cylinders heads (part 2). Cut it of from the casting blocks.



Next. mount at the cylinders tops. Use any two-component glue, to have time for positioning. Only correct position is possible (elements have positioning dowels). Be careful, these elements are really fragile!



Now it's time for a thrust box and induction pipes. firstly remove thrust box (15) from the casting block. For easier handling, you can attach any match or toothpick to casting block.



You can use razor saw, but you should do this with care - it's really easy to damage this element during cutting. As in the case of crank case, you can use milling machine for final sanding.



Next remove lower induction pipes (22) from the casting block. Do this in the correct spot, like depicted below.



Attach prepared lower induction pipes to the thrust box. Do not confuse direction!



Having the crankcase with lower induction pipes put together, attach this element to the crankcase. Keep correct geometry - looking from the back, induction pipes (parts 21) should be parallel to cylinders.



« Last Edit: August 30, 2015, 06:35:57 AM by taurusmodels »

Offline janh

  • Full Member
  • ***
  • Posts: 130
Re: Bentley Br2 step-by-step building
« Reply #1 on: August 30, 2015, 08:24:24 PM »
it would be an idea to replace the cylinder fasteners with hypodermic needles, what's the outer diameter??

Offline taurusmodels

  • Moderator
  • Full Member
  • *****
  • Posts: 235
Re: Bentley Br2 step-by-step building
« Reply #2 on: August 30, 2015, 09:21:29 PM »
it would be an idea to replace the cylinder fasteners with hypodermic needles, what's the outer diameter??

The problem is cutting at a correct length - you must do this AFTER attaching fasteners to cylinders - in the case of resin it's extremely easy - just block by a match stick and cut. In the case of needle it could be hard to do....
The diameter od this fastening sticks is 0.45mm.

My idea for fastening of the cylinders was little different. In a first version crankcase has pre-drilled holes. You was able to mount cylinders with fasteners and heads, and just put into the holes. Unfortunately, I shifted just a little a few holes (it was only up to 0.15mm!) and whole geometry of engine failed....
I had to prepare a new crankcase with no holes. It's more difficult to assembly the cylinders, but you can keep perfect geometry.

All the best, Lukasz