Three Cylinder Radial Engine

[sbwhart]

Hi Chaps

At Model engineering exhibitions I've alway marveled at the models of radial aircraft engines, now this isn't going to be a petrol engine, but it going to be based on two design of model radial steam engines, I'm going to try and take what I think are the best parts in terms of good design and ease of manufacture from these two designs, plus a bit of bling so that they represent an aircraft engine (cooling fins on the cylinders)

The two design I'm going to work with are:-

The Cygnet Royal by Edgar T Westbury, I got my drawing free from Model Engineer but you can buy them from http://www.myhobbystore.com I understand that you can buy a set of castings for this design but I'm going to use bar stock.

Elmers Radial Engine drawings are available on John Tom http://www.john-tom.com/ElmersEngines/11_Radial.pdf

I've been planning this build for some time slowly putting my ideas together and doing a bit of research and I've started on a set of metric drawings as all my kit is metric, and to get round me the material and tools required.



I'm just short of some 2" dia ally but I've just ordered  a 250mm length from ebay, the rest of the stuff came from my stash or as is the case of the chunk of sash weight cast iron from John, and the bearings were donated by Dave Bluchip

Thanks chaps  

To make the boring bar for the crank case I copied out the sectioned drawing at a 1 - 1 scale and used this as a guide to grind the bar, and yes I know its the wrong way but I'm going to run the lathe in revers its easy to see what's going on that way.



This is it ground up



Then with a chunk of ally in the lathe a start was made on the crank case, skim up the OD, centre drill then a series of drill, and then with a boring bar it was roughed out.



Well thats it every project begins and end on the lathe.

Have fun

Stew
 

[NickG]

That sounds like a nice project Stew. Your little break project is probably larger than anything I've tackled so far! 

Can't wait to watch this one unfold.

Nick

[Darren]

This will be an interesting one to follow .... what's in your tailstock 

[sbwhart]

This will be an interesting one to follow .... what's in your tailstock 

A cork out of a bottle of bubbly to keep the s**t out. 

Stew

[rleete]

what's in your tailstock 

That's a rather personal question, doncha think?

[Russel]

I really like radial engines...looking forward to your build!

Russ

[Brass_Machine]

Radial engine fan meself. Watching this one!

Eric

[Stilldrillin]

That looks a very interesting project Stew..... 

Good luck! I`m watching, quietly..... 

David D

[sbwhart]

Well chaps here's some more.

Finished off the bore and then brought everything to finished size, Home made boring bar worked fine, although I had to trim a bit more off it to keep it clear of the job.



Now your going to love this bit.

Keeping the job in the chuck the whole lot was transfered to :----------------------------- wait for it wait for it:-----------------------------------------






The indexer.

First job with a wobbler find the edges of the job:- zero the X on centre line and zero the Y on the front edge.





With the fly cutter I then made the round bar into an hexagon, this is where the table stops paid for them self with the stops set I had no worries about running into the chuck.

Forget to take a pic of the fly cutting but you've seen that before.

Move the Y to where the cylinders will be mounted and zero the dro again from know on all features will be from the centre line of this hole.

Centre drill then roughing drill to get the meat out. Note use of support Jack



And then with the boring head rough out all the to within 0.5 mm



Thats it for today.
 
Have fun

Stew

[John Hill]

Nice work! 

[thinks] I really, really need to buy more toys! [/thinks]

[Gerhard Olivier]

Nice work there Stew

Gerhard

[raynerd]

  clock?       wheel cutters 

lol, looks like a good build. I`ll be watching!



 

Chris

[Darren]

Nice work! 

[thinks] I really, really need to buy more toys! [/thinks]

Me too ............


Looking good Stew.....looking good....

[bogstandard]

Very nice Stew.

Now you can see where I was coming from with interchangeable tooling, it saves hours in setup times. One chuck fits all.


John

[NickG]

Stew, very nice. That indexer and interchangable chuck is going to be a godsend!

Nick

[chuck foster]

looking good stew 

chuck 

[Divided he ad]

Nice!  You don't half like a challenge!!! 

looks like this retirement thing is going to be a lot of fun for you Stew 




Looking forward to seeing this unfold 





Ralph.

[sbwhart]

Well a bit more done today

With all the cylinder holes rouged out, brought the first one to size, then as I wanted all to be the same, it'll make things easy down line, the boring bar was clamp up and the other two finished at the same setting.

One of the reasons I've reproduced the drawing in cad was that I wanted all the holes dimensioned from the centre line of the cylinders this way I can make best use of the DRO, so to drill the holes move the table to the x and Y location drill the hole, rotate the spin indexer drill the same hole in the other face, spin index drill the same hole in the third face reposition the table x and Y etc etc

Like this



And here we are with all the holes drilled in the horizontal position including the breather hole tapped 3/8*40 ME I'll tap the M3 holes on my tapping table.



I enjoyed that it took me just over an hour.

Have fun

Stew

[Stilldrillin]

Stew,

The way you tackled that op looks very perfeshnial...... 

David D

[sbwhart]

Thanks guys

Got a bit more done this morning.

Took the chuck off the indexer and mounted it on the Rotary table, There was no real need to mount it on the rotary table but as I was planing to use the PCD feature of my DRO for the first time to drill a sequence of holes, I was edging my bets, and besides it would be easy to clamp and line things up with the RO.

Not much head space:-



First job get one face of the Hex level with a DTI.



Next centre the bore with the centre line of the quill:- to do this you rotate the quill and manipulate the X and Y until you have zero clock movement



Then set the parameters into the DRO:- Centre, PCD, number of holes, start and end angles.

Then all you do is set it at hole 1 move the x and y until both read zero your on position for hole 1 repeat for hole 2, et etc



At first I just slightly marked each hole then checked that all was OK before centre drilling and then drilled for M3.



Then with the job still in the chuck back to the lathe for parting off.



I was really pleased just how easy that was with the DRO it really came into its own with that job.
 


Cheers

Stew

[Darren]

Very nice Stew, wish I had the confidence to tackle a project like this 

[Divided he ad]

Not much head space:

       I noticed that when I came round for the little visit!!  That shop was built for one man.... And he's making little wonders in it!

I really like the DRO's that you guys have, makes things much easier to do..... I think I'll have to wait a while for that though.... Either that of figure out how to make my shop pay 



Very good looking job so far Stew, nice to see it all taking shape 



Ralph.

[sbwhart]

Very nice Stew, wish I had the confidence to tackle a project like this 

Darren with the great job your doing on your machinery you'll soon be knocking out some superb work.

This is the first real test I've given the DRO one of the reason I wanted to make a Radial is that they have lots a features to test the DRO on, you don't need a DRO to do all of this work but what it does is take the pain of dealing with back lash out of your machine so it makes thing a  lot simpler.

Any way got a little bit more done:-

With the job parted off I set it up in the chuck to face it off to length, when disaster struck, the @£$%%^&* thing flipped out of the chuck putting a few dings in it, luckily they are in places that won't be seen when its all assembled together, so set it up in the mill vice to fly cut it off to length.

Now for the port face:-

A little bit more setting up required for this.

First as it will be easy to put features in the wrong orientation, I marked the job up where things were to go checking and double checking I'd got it correct,  it wasn't accurately marked just enough to keep me on the straight and narrow.



Next get the job on the RT centre line, to do this you rotate the RT, as I was using a three jaw self centre chuck I had to keep channing the position of the job in the chuck and tightening up on different jaws to find the best place I got it to 0.1mm run out well fit for function.



Next I had to get the hexagon in the correct orientation by clocking up a face level with the RT on zero.



Then get the job on the centre line of the quill (spindle) to do this you hold the DTI in the spindle and rotate the spindle.



Then use the DRO drill the holes in this case one set of 6 and one set of 3.



At this point domestic duties were beginning to call so called it a day.

Cheers

Stew

[NickG]

Nice work Stew, we're all getting DRO envy here. Lucky escape with the little mishap, it's a relief when that happens!

Nick

[sbwhart]

Ok last bit of work on the crank case:- cut the steam galleries, the drawing calls for the angle from edge to edge to be 60 deg, but for machining the critical feature is centre to centre of the cutter I'm using a 2mm slot drill so drew it up in cad and checked the cutter centre to centre angle 44 deg.

The mill was still set on the centre of the job, move the radius distance to where the ports will be, and rotated the RT 30 deg then off set 1mm to allow 1/2 cutter dia. lower the cutter 1 mm into work and rotate RT 44 deg. To make things simple I worked out the movement of the RT in advance and wrote out a crib sheet.

Like this



Ports cut



Last job tap all the holes:- I used my home made tapping stand, so that they were all tapped nice and square.





And there we are Crank case done.




Made a start on the cylinders I'm going to make these from ally with cast iron liners.

2" diameter length of ally being turned down.



I was hopping to get four cylinders out of this ally (one spare) but I forgot about the width of the parting tool so only got three, I'll have to be real carful

When making multiples its important to get certain key feature as near as posable all the same size, in this case its the width and the bore dia.

So by putting the job hard up against the back of the chuck and zeroing up the cross slide they were all faced off the same length.



Because of how I'm going to machine things down line I'm not particularly worried about getting the bore concentric with the OD. So sticking the blanks back in the chuck all the bores were centre drilled and drilled out with bigger and bigger drills.



They were all then rough out to within 1/2 mm of finish size with a boring bar.

Then finished off to size with the boring bar:- one after the other at the same setting, running the final cut through a couple of times to take the spring out of the bar.

For length they were all within 0.05mm and for dia 0.02 mm thats well fit for purpose.

Here they all are.



Next job the cast iron sleeves.

Have fun

Stew