Member postings for Ramon Wilson

Very nice result Geoff so I hope you have even more success with it running - nothing beats that huge grin that breaks out when an engine you've made breaks into it's first run

Best - Tug

I just found out that the search suggested will not be easy to find!

Here are the direct links to the build threads

ETA

Oliver

You'll have to scroll through but may find something of interest

Best - Tug

Hi Hans, only just become aware of these latest posts.

Though I haven't made a Nalon Viper as such I have made several engines with very similar liners and virtually identical exhaust and transfer porting layout

I have described this quite fully on build threads on the Model Engine Maker site - search for ETA and Oliver Tiger.

I use a cross slide milling attachment to 'drill' the transfer holes - I use an undersized FC3 milling cutter (eg 2.5 for a 3mm final size) to begin the hole until I have a full flat bottom surface then spot and drill through with a 2.5 drill being very careful on breakthrough though if the liner is mounted on a sacrificial mandrel that's not an issue. Once the initial hole is done I open up using another FC3 cutter to open to size right through. Depending on the wall thickness and angle of approach you may have to grind some of the cutter away on the shank to get the depth required.

I use the corner of the exhaust flange as a reference point to establish where to start the hole but a faint line scribed around the liner in the correct vertical position using the lathe and picking up with a sharp pointer at the angle required will be good enough unless you are seeking absolute perfection with accuracy of transfer timing.

Hope that helps some more

Best - Tug

Hi again, further to that last post I thought you might find these helpful

Hello Michael from a fellow engine lover.

I re-bored and rebuilt a quite old and abused air cooled Taplin Twin many years ago and as John says they are BA threads on the original engines. They would either be 6 or 5BA from memory. Later versions were made in India I believe but whether they had BA threads or not I have no idea.

The version I did had a very soft aluminium cast case with several threads stripped. I bored out all tapped holes and made threaded inserts out of a much better aluminium material before drilling and re tapping the holes which worked well. It started very easily and ran extremely well though a strange feel on flicking after so many single cylinders before

This was well before I owned a digital camera I'm afraid so have no images that I can recall

Good luck with yours

Best - Tug

Ha! You need say no more Hans, but you are welcome to come back if you change your mind.

Good luck with the Viper if you go ahead with it.

Best - Tug

Hans, as you have found the 'Model Engine News' site is no longer functional.

The plans are available somewhere as is the collection of plans from the 'Motor Boys'. I believe Ken Croft made these available from a free download but as to where to find them I cannot recall. Ken does visit on here so maybe he can re enlighten us if he reads this.

Like Roy I have the Viper plans and the others from the Motor Boys e book on file so happy to help if wanted

Best - Tug

Hi Keith, it certainly features in the odd side port design of the times so who knows? Mills engines did start well for the best part so maybe it has some effect - very few diesels have stepped or baffled pistons though.

I'm going to be offline for a few days - back later though

Best Tug

Well how about that Keith

I can't say I can remember that as I wouldn't see an Aeromodeller magazine until 1958 (age 13) but I did collect them back as far as 1944 and do remember the adverts generally.

I've looked at some other side port drawings some have a step in the piston on the transfer side others don't but as said if it isn't there by the piston being wrongly installed the timing is affected quite badly so was Mills making a thing of it as a sales pitch - after all why not do the same on all pistons at the point of transfer if it's that effective - who knows?

I've had quite a few Mills through my hands over the years all of which were accompanied by a 'Can't get it to run' comment. Some were simply worn and required new pistons but a high percentage of them all had the pistons in back to front.

Best - Tug

Re the Mills comment Keith,

I always thought that the piston was stepped to give the desired inlet  transfer timing as opposed to a technical improvement reason. Did they advertise that as a feature at the time? There were those series of adverts in Aeromodeller that consecutively described the Mills attributes but that doesn't ring a bell. Besides - if a Mills piston is fitted in the wrong way round it will fire on a prime but will not run.

Re Neil's comment on old castor in bearings - this was the inside of a Merco 61 I rebuilt a while back

Edited By Ramon Wilson on 06/09/2023 13:50:03 Inlet should have been transfer

Edited By Ramon Wilson on 06/09/2023 13:51:20

Though I'm sure Keith wouldn't mind Roy I agree - will reply later, painting the shed at the mo

Tug

Hah! Now why didn't that occur to me!

I'd say that's a great case of lateral thinking Roy

I can't recall the last time I visited a model shop the local ones long gone. For many years I've only used fuel from the husband and wife team of 'Southern Modelcraft' in Kent. Unfortunately only available from them at shows they attend or at their premises they do not supply shops nor will send it by courier but the quality is superb with consistent performance.

Though they do do synthetic based (glow) fuel I only use their castor based 5% nitro for glow and their Sport and Hi-performance diesel. As previously mentioned elsewhere the diesel will keep for years in a tightly capped tin but the castor in glow fuel for some reason can degrade if allowed to get cold in storage. Apparently that can be put right by heating the fuel but I've not tried it to say positively.

My days of visiting shows have come to and end but fortunately I have squirrelled enough of both to see the rest of my (control line) flying days out - I hope!

What do you fly BTW

Best - Tug

Thanks Roy

Yes I did realise that the edge of the cone defines the timing but was thinking that if flat topped at that point the contra piston would need to be quite long to compensate for the loss - I assume lengthening the CP is how you dealt with the change?

I could never quite understand the thinking behind the second CI cylinder head version, from any aspect, though there are one or two commercial engines that have steel integral liners and fins, the ED 3.46 for one.

Bernard - I guess that sums up the 'current' situation with electric power overtaking IC power

Usually, small capacity glow motors run best on fuel with a Nitromethane content - (5 - 10%) if you didn't get any and can wait I can let you have some at LowMex, just let me know beforehand.

Tug

Hi Keith,

I have now disposed of my hard copies of the various drawings the only ones I have being PDFs on file. These were updated to the 24-12-2011.

The 3/16 port depth on previous issues was a typo. The port height is 3/32 (.092) and the 3/16 is the width of port with the cutter at correct depth.

My drawing shows an unusual heavily tapered top piston with a recessed contra piston to match. The CP is bored from the top the recess being .100" deep with the land between top and bottom recess apx ..090.

Were I to make one I think I would be inclined to make the piston flat topped but this of course would mean rearranging the port heights to suit the desired timing. I only got as far as making the cases on my intention for 5cc versions I'm afraid.

I may be wrong but I believe Ron Chernich did the actual drawings from information provided by Eric te style is certainly Ron's

As you comment, quite a few have been made - far more than the prototypes for sure. I don't know why an all cast liner/cylinder was seen as a potential advantage - heavier of course than the conventional set up. It should be borne in mind that the original was specifically destined to be used in Team Race etc. as an alternative to the growing dominance of the Oliver Tiger so any increase in weight is a disadvantage to my mind. I don't know if anyone has built that version - as you say it would be interesting to hear from them if so.

All of this is not good for my peace of mind

Best - Tug

Edited By Ramon Wilson on 05/09/2023 11:08:33

Hello Keith,

Like you I felt the need to reread the old thread again and without going all over it again I remain unchanged in my thoughts as to seating the bearings - in a home made engine of this kind - though of course many commercial TBR engines have the same situation.

With regard to the same size bearings - the jury seems to be out on this over at the Barton site. No one has recalled the discussion I thought had taken place on there though of course that doesn't mean it wasn't. There is some mention of potential harmonics but nothing fact based and many pointing out that same size bearings are okay. I wish I could remember where I saw it but I can't and anyway at our level it doesn't seem to matter.

Why I prefer the larger rear bearing (which takes the radial loads) and a smaller front bearing which takes the axial ones is mainly due to the ease of ensuring the inner race at the front is firmly nipped between the step on the shaft and the prop driver collet when the prop is tightened. That it may have some potential increase in performance (over same size bearings) has never been in my thoughts and as we've all been there before theres no point in repetition of discussion I guess.

Heat build up in the cylinder is to be expected on bench running and indeed inside a closely cowled 'bonnet'. Running in will soon produce heat, so fast, but not leaned out, short runs are better than long rich ones not allowing the heat to build to rapidly and allowing the engine to cool before repeating. 

A fine pitch prop say 4" or less will allow the engine to 'run' without placing too much load on it - 6" pitch or more is not ideal as even with a smaller diameter the load is more than what is ideal at the early stage of running.

A cast piston in a cast liner is a good combination material wise (though not the best) but even the best of initial compression will ease as the surfaces wear quite quickly on those early runs with the oily black exhaust residue giving clear indication. If the parts are unhardened then the best combination is that recommended by that long ceased engine 'guru' George Aldrich - a Meehanite or (continuous cast) piston in free cutting steel making the contra piston from the same cast.

With regard to seals - I do use sealed bearings if open ones aren't available but always remove the seals before fitting. If that front bearing becomes gummed with castor it's much easier to free with a drop of cellulose behind the prop driver - difficult with a seal fitted.

All this engine talk is whetting my appetite but fortunately(?) the workshop isn't up and running as we speak. I do have the need for a good 3.5cc for a team race model - a bored out Viper might just be worth considering.

All the best for that next project

Tug

Edited By Ramon Wilson on 04/09/2023 16:08:59

Hi Guys,

I think i saw this being discussed some time back on the Barton Control Line Model forum and my memory, vague as it is on recent things, was that it was on similar lines to 'Dio's' comments but as said not completely sure and didn't pay too much attention to it at the time. It was probably in connection with high end motors designed for Team Racing use.

I popped a question up last night on there to see if anyone could comment further. Nothing detailed for or against as yet but found it interesting to say the least that three engines I have (ED 2.46 'Racer', Frog 2.49 and the 2.5cc DC Rapier - all diesels) all have same size ball race front and back. Whether they have the same number of balls in each I would have no idea without stripping them down.

With the Nalon very similar in layout to the ED Racer I can't imagine any issues with your version Keith but seeing you had mentioned it it rang a bell.

What that needs now Keith is a nice Vintage A team race model around it

Best - Tug

Edited By Ramon Wilson on 31/08/2023 10:17:42

Hello Keith,

Another nice result and good looking engine. Lovely anodising too

Have you hardened the liner or is it stock EN1a ? Reason for asking is that the new contra piston raises the possibility of galling and will be a beggar to remove if it does - just a thought to consider.

The original was, I believe, designed to offer an alternative to the Oliver Tiger in T/R so much more than a sport engine I would say so it should have great potential for further running

I like to keep the prop pitch down to 4" -5" at most for early runs, 6" provides too much load which can lead to quick heat build up as I'm sure your aware.

I have a feeling that it is not a good idea to use identical bearings to support the crankshaft too though cannot think why. I do remember a discussion on this somewhere in the past explaining the reason but having looked cannot find any reference. This would be for an engine with an intended working life I'm sure, can't see that it would make much difference for an ME project.

As said though, lovely result, you should be well proud

Best - Tug

Hi Rod,

Providing it's well stoppered diesel fuel will keep for years in a tin. Some years back at a swapmeet I bought an old tin of Keil Kraft fuel - specifically for the tin itself. It was about 2/3 full however and yes it still worked ok though exactly how old it was I have no idea. I use Southern Modelcraft fuel and used to buy it at shows so have a decent stock. Current 2.5 litre tin in use is marked (by me) 2014. Slightest leak though it's another story as that ether soon depletes.

Bob - not sure how old you are but I bought my first half pint can of KK fuel c1958. Something tells me that was around 3 shillings (3/3d?) but the pint tin was 4/6d. It was rare - for me - to be able to afford the pint tin! Four years later and I'm in the army - a pint of beer was around 1/4d if memory serves correct but even that is now approaching untenable expenditure - the inflation on diesel is far greater it would seem and yes it is an expensive commodity.

Even paraffin has suffered the same - just bought 4 litres for a penny short of nine quid

As far as I'm aware there are only two suppliers of (castor based) diesel fuel now. Southern Modelcraft whose proprieter is retiring this coming year and the company that took over Model Technics whose outlet for diesel is Leeds Model Shop as Rod says.

Western Engines does 'ED Super Zip' but this is a synthetic oil based fuel.

Making or running model diesel engines has unfortunately become an expensive pastime!

Best - Tug

Yes looking good Geoff hope you've got plenty of fuel

I agree with Keith that unless you are going to use it in anger so to speak a comp screw lock is not essential but handy if the engine does show a tendency to back off compression whilst running.

Vibration is usually the cause but a less than ideal fit on the contra piston doesn't help either. A small mod that helps is to drill the end of the comp screw to give a circular land rather than a potential point contact. Doesn't have to be deep just deep enough.

Good luck with the final phase

Best - Tug

Hi Bob,

Nitromethane in glow fuel is basically there to increase power and, as Andrew points out, is not something to be used in the make up of 'diesel' fuel. As the nitro increases in percentage so the mechanics of the enginee need to change to accommodate it.

Basically  -  'Ignition improver' on the other hand is used to smooth the ignition point in compression ignition engines. I'm not aware of 'Octyl' nitrate being used for this but this may be a substitute for IPN (Iso Propyl (?) Nitrate - I think)

Outside of some esoteric, very dangerous substances, power increase in normal CI engine fuel - commonly referred to as 'diesel' fuel - is usually achieved by increasing the paraffin content at the expense of the ether and/or oil content, the ignition improver remaining constant within a half percent or so.

Diesel fuel has now become prohibitively expensive at the (very) few sources available. For years I have used fuel produced by Southern Modelcraft based in Tonbridge in Kent but that, unfortunately, is collection only or from their stand at the model shows they attend. They will also sell ether and gnition improver as well as castor oil but there is no real advantage of mixing your own over buying it in half gallon sizes.

I guess this is for your rebuilt ED 3.46 so if you do manage to find some, or the ingredients for it, hope it runs well for you

Best - Tug

PS I note in a previous post from 2012 I stated the Southern Modelcraft 'Sport Mix' was £12.50 per 2.5 Litres - that's now £28.00 !!  That said it is still the least expensive available I believe.

Edited By Ramon Wilson on 24/08/2023 14:13:58

Edited By Ramon Wilson on 24/08/2023 14:19:07