Whittle V8 – Crankshaft

[Steve WithnellParticipant @stevewithnell34426]

Anyone know which article the con-rod drawings appear? I’ve been through the ME PDF’s a number of times, but can’t find the drawings though the text does refer to them.

 

Regards

 

Steve

[Steve WithnellParticipant @stevewithnell34426]

 

It’s done for now. Wouldn’t score 9/10 one or two non-functional errors, but reasonably pleased with the outcome.

 

 

I now need to address some shortcomings in my lathe! Whenever I do a job that’s harder /more complex than the last one, it always seems to flush out an improvement need…

 

Steve

[John Stevenson 1Participant @johnstevenson1]

Steve,

 

Use a variation of a cat head steady.

 

 

Simple tube with 3 or better still 4 set screws so you can get the OD running true.

 

Then run the OD in a steady.

 

Obviously scaled down to suit your machine.

 

John S.

[Anonymous]

Steve: Looks pretty damn fine to me! Non-functional errors, pah, as long as it does the job no problem. Nobody will ever notice anyway.

 

Regards,

 

Andrew

[Jeff DaymanParticipant @jeffdayman43397]

Congratulations on a fine job on your crank Steve. Looks great.

 

JD

[Steve WithnellParticipant @stevewithnell34426]

Now completed the prop driver –

 

http://wp.me/p17x3s-1a

 

This short link points at my WordPress blog.

 

Steve

 

 

[Ramon WilsonParticipant @ramonwilson3]

Hi Steve – just caught up with this.

 

Congratulations on a fine result. Now the testing bit begins – all the ‘multiples’.

 

Did you experience any warping after all machining was completed and what material did you use? Keep us posted on progresss

 

Regards – Ramon

[Steve WithnellParticipant @stevewithnell34426]

Thanks Ramon, if my engine looks as smart as your ED series, then I’ll be delighted!

 

I’ve never done more than one part fit another, so making 8’s and 16’s all the same is quite daunting.

 

I’ve not noticed any distortion, but I have left the centre main significantly over size so I can address any alignment issues before fitting in the crankcase.

 

I used EN8T because I expect that the lifetime running will be less than two hours, whereas I think Mr Whittle was building a product quality engine. Having said that I do want to fly the motor in an appropriate airframe.

 

I have had a run at EN16T as specified, gee whiz it’s hard stuff. I reckon you need a real man’s lathe to deal with it, rather than my Chinese bench lathe. I’ll have another run it at some point, maybe try cutting one of the cylinders, I guess it’s just another material to learn.

 

Best Regards

 

Steve

 

 

[Ramon WilsonParticipant @ramonwilson3]

Well Steve if you’ve made that from EN8 you shouldn’t really have too much of a problem with16T.

 

I find that those last few thou though have to be done with a freshly ground tool for the best results with high-ish speed and low feed. ‘Files’ made from wet and dry paper stuck to something flat like ground flat stock or the edge or face of a parallel with double sided sticky tape and used with parafin give good control over quality of finish/dimension.

 

I’m off to the model aircraft Nats tomorrow – first time for several years, even finished a plane I began in 05 but it looks like the weather is going to run true to form – wet and windy all weekend, fine from Monday afternoon onwards

 

Regards – Ramon

[Steve WithnellParticipant @stevewithnell34426]

Enjoy the NATS, haven’t been to an RC event for a very long while, but I am thinking about sticking the V8 in the Flair SE5a, it has very good reviews for stability and the fullsize version did run a V8, but I need a copy of the front fuse plans to see if it will accomodate the V8 or can be modified to do so.

 

Been really busy, so haven’t had chance to call Flair to see if they will share the plans.

 

It will take at least a year for me to get the V8 done, so perhaps I getting ahead of myself!

 

Steve

[Brian ProllParticipant @brianproll50309]

To further the problem of chatter whilst m/c ing the crank I would suggest that you start at the tailstock end of the crank and rough each one down until a round portion is formed.

Carry on m/cing all the main bearings and throws to a state whereby 70-80% of the metal has ben removed.

From this state starting again at the tailstock end m/c the first throw to say + 3 thou.

In this gap between the webs place a snug fitting spacer of say ally and ty-rap to secure.

Carry on doing all the remainding throws the same way forgetting the main journals till the last.

Using spacers this way more tailstock pressure can be used to keep things solid.

Finally reduce the main journals to say +0.0005 and give the throws the final polish

and you should have a nice straight crank.

PS using the turning between centres method I would recommend zip tying the dog to the driver on the plate to stop vibes and backlash.

Using this method I made a 6 throw crank from en24t with hardly any probs on my Chester Crafsman.

 

Brian.

Edited By Brian Proll on 06/09/2011 00:51:39

[Steve Talbot 1Participant @stevetalbot1]

Have been reading the articles on the E.W. V8 Aero Engine with great interest.

Noticed that glow plug holes have been tapped 1/4″ x 32 ME. Just reading a model aero mag where they give the glow plug thread as 1/4″ x 32 UNF -EF where EF is Extra Fine.

(Brian Winch RCM&E July 2008) Hope this may help.

Steve T

[Steve WithnellParticipant @stevewithnell34426]

Ah but…the plugs Mr Whittle calls out for his design are Enya No3’s and these are then heavily modified. One of those mods is to screw cut a new thread on the plug to be a “snug fit” in the cylinder head which has been previously tapped 3/16 x 40 tpi.

 

So doesn’t matter what the plug was (I think 1/4 x 32 IIRC)

 

No where near this stage of the build pretty much zero progress since before Christmas.

 

Steve

[Michael HornerParticipant @michaelhorner54327]

Hi Steve

On my copy conrods are in section 6. To make it easier to find i added the main subject as part of the file name.

 

I would say your crank looks pretty good but there is no picture! Keep the tips coming. I’m doing the barrels via cnc, I don’t have Mr Whittles patience!

 

I am pondering the crank, do I do it the JS way or on the lathe?

 

Cheers Mike.

[Steve WithnellParticipant @stevewithnell34426]

If I had a CNC machine, I’d do it the JS way, but leave the journal pins oversize and finish them on the lathe, as Andrew reckons the pins will be slightly barrel shaped which is not what you need. I manually rough out the crank on the mill anyway.

 

The whole build is here http://wp.me/p17x3s-1a in words and pictures!

 

I’m gearing up to have another run at this now Christmas is past.

 

Steve

[Michael HornerParticipant @michaelhorner54327]

Hi Steve

Thats the ponder, if I do it the JS way there won’t be any crankpin centres so once you dismount it there isn’t anything to referance to so it will have to be a finished job. I’ve thought about the barrelling and may be once the pin is nearly to size pull back the cutter in the Y so that the edge of the cutter is on the centre line of the pin. can only try.

Cheers Mike.

[Steve WithnellParticipant @stevewithnell34426]

There will be if you put the centres in before setting up in the CNC. If the three centres are set up so they form three points on a line perpendicular to the table, it should be possible to get decent alignment. Then you have the option to move to the lathe if you need to?

 

Steve

[Steve WithnellParticipant @stevewithnell34426]

Out of hibernation and charging ahead making slow progress again. Only two speeds with this project. slow and stopped.

http://whittlev8.wordpress.com/

[John Stevenson 1Participant @johnstevenson1]

Just an update on doing a crank on the CNC.

We first did this at the Midlands show last year and normally try to do something different at each show [ Engraving is boooooring ]

However quite a few people who didn't get the the Midlands show last year have emailed us to see if we will run the same demo this year at Harrogate, so the larger KX3 on the ARC stand will be doing cranks over the show days.

Not certain what the little KX1 will be doing, If everything works out with Art fenerty of Mach3 and Gearotic fame we may be doing bevel gears with just a very simple cutter, fingers crossed.

John S.

[Michael HornerParticipant @michaelhorner54327]

Welcome back from hibernation Steve.

I have been chugging along with my version of the Whittle V8.On my last attempt at the crankshaft I didn't bend it but I did manage to remove to much metal with the mill , and that was being careful! I gave up on the idea of CNCing the crank it was making my brain hurt. I am now working on the conrods, getting there slowly. The cap bolt holes were off to one side, think I've got that sorted now. I was hoping to do them M2 but there isn't enough metal so I am going to try M1.6

Michael

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