Firefly .46 crankcase

Good to hear the photos are of Use Edmund, I'm sure there are other ways of doing things depending on what you have to hand if you do have any queries just ask. I've added a few more tonight.

David look forward to seeing the other set of photos.

J

I'm glad to read this thread cos I've just spent half an hour wondering where the hell the 30mm diameter is. I was just about to post on the beginners section about it when the new format drew me to this thread. Score one for the new format.

Well the crankcase and bearing are complete all bar a bit of blending and final cleaning up but that will have to wait until all the other parts are complete. I went my own way slightly with teh nose chamfers and turning. There are some more photos of the final stages in my album.

I think I will start another thread about teh build so it does not get lost in this one which is really about article errors & omissions.

J

Edited By JasonB on 22/06/2012 21:02:24

A separate "clean" thread detailing the build woud be a super resource, so here is one vote for "Yes please"!

edmund

And has already been mentioned , here's another 'yes' for a build thread.......Please..

Chris

OK I'll get it going.

Just added some more photos of the barrel.

J

Hi all,

Sorry to hijack this thread but the question is sort of pertinent to the engine and I don't want to start a whole new thread.

I am beginning a build of Firefly and I have most of the materials to hand but I have no source of Dural for the con rod. I have looked on the website of most suppliers I use, but no luck and a Google question just gets me to industrial supopliers. As I only need a small piece can anyone suggest a source or an readily available alternative material. This is my first i.c. engine so am usure of the requirements.

Thanks for reading and sorry again Jason for this hijack,

Best regards

Terry

Terry,

A roughly equivalent aluminium/copper alloy is 2014, available in small quantities from M-Machine in the UK. The 2xxx alloys can be prone to stress corrosion cracking, so in the aerospace industry they're being replaced by 7xxx alloys, the most common of which is 7075. However, 7075 is more difficult to get in small quantites, and is a bit more difficult to machine.

Regards,

Andrew

Terry, I can't help you with a supplier, but what you need is an Aluminium alloy from the Al-Cu-Mg group, with around 4 % Copper. Other brand names are Avional, Aludur. For more informations consult Wikipedia.

The table under DIN 1725 gives the appropriate W-numbers, if these can help you...

Here it is: http://tinyurl.com/6o45y4z

Greetings, Hansrudolf

Hi Terry

College Engineering will be able to supply you with some HE15 ali which will do just fine for this task. I'm literally just about to machine two rods for my latest build from some having got it out on the bench this morning. I bought mine from them at the Midlands show - they had 3/8 and 1/2 dia and Noggin End metals had some 3/8 x 1 flat bar too both at reasonable cost

Good luck with yours - Ramon

Thanks all,

I tried Noggin ends Ramon, but at £8.00 for a 12" length of 1/4 x 5/8 and £6.00 postage it's a bit steep. Looks like I'll have to wait for the next exhibition. Its a pity that the aerospace industry round here in Lutterworth has disappeared. Pretty ironic as Whittle developed most of his jet engine here at Ladywood works - and the main buildings survive as industrial units. The English Electric (later BAe) facilities i.e. workshops, hangars and runway are now a storage and distribution park. Sign of the times!

Best regards

Terry

PS CES charge £7.80 for P&P for a 12" bar of 1/2 dia HE15.  To put this in perspective, the HE15 would weigh around 90 grams.  This morning a new soft faced hammer weighing just shy of 600 grams was delivered here by Royal Mail, it was very well packed and the P&P charges were £2.00 inc.

T

Edited By Terryd on 25/06/2012 14:21:50

Hi Terry I can see why you'd baulk at that Terry - postage is a real killer wih some companies.

Alls not lost though - PM sent

I got some delivered on friday from M-machine listed on their site as HE15, full spec is 2014AT6 together with a foot of 30mmEN8

To get a decent bit to hold I bought a 4" length of 1"sq and that cost me £3.60. They have smaller sections but the 1" sq was a better deal There were other metals on teh order which probably weighed 3kg and postage was £7.08 bothe plus VAT.

The thing with CES deliveries is that you can order several Kgs of material for the same postage cost, as its a flat charge, does not help that their EN1A is twice the price of M-machine though.

J

I spotted the error with the 30mm hole and did it to the correct size but unfortunately I did not pick up the next error which is to mill the flat sides to a wall thickness of 3.75mm. I did this without giving it too much thought and guess what, it dont work with a 28.2mm hole! I am just under 2mm short now.

I am a bit miffed that this is given as a beginners engine but the description has these errors in. I know I could have worked it out from the drawing but I am the beginner they talk about and I didnt. I guess the first lesson learnt here is dont rely on someones description.

David, maybe you could print a correction each fortnight in ME and then us beginners could just build a fortnight behind and hopefully get it done without too much scrap.

Thanks

Hi There

We have printed a correction but it does not go to press until tomorrow and then not in Smiths for another two weeks.

It takes 2 or 3 issues to get corrections done as we work so far ahead.

regards david

Richard, you should still have enough meat in the crankcase, so its not a scrapper, just say you have gone for the streamed line version.

Issue 4433 does have a correction note about the 30 vs 28.2 but does not mention the 3.75mm that is affected by it.

Richard I'm building ahead of the mag so just keep a look out here for anything I spot. I've just added some of the barrel to my build log tonight.

J