Nalon Viper

[Graham Williams 11Participant @grahamwilliams11]

Made the front housing out of the only piece of 6061 Alum ( plans indicate this spec) I had and started looking for more to make the c/case, backplate etc. Seems none of the suppliers to the model trade offer this spec and after searching online seems only the big boys list it. Haven't approached anyone yet to see if they'll supply but past experiences haven't been positive in the quantities I've wanted. Anyone know of someone who might oblige?

Cheers

GW

[Graham Williams 11Participant @grahamwilliams11]

Alum stockist

[john feeneyParticipant @johnfeeney58965]

Hi Graham,

I,ve made many similar I.C engines and used 6082 T6. It,s readily available. If you let me know the sizes I have many kilo"s of assorted section and cut what you need.

Regards,

John Feeney

[JasonBModerator @jasonb]

As said 6082 is fine or several of the ME suppliers will still be listing it as HE30. 

Edited By JasonB on 13/10/2019 14:12:11

[Graham Williams 11Participant @grahamwilliams11]

Thanks guys and thanks for the offer John. 6082 is readily available locally but as the Viper was/is a high performance engine (in its day) believed that the spec quoted was necessary over the 6082. will make a cheeky 'phone call to the local Aalco tomorrow on the off chance that they'll help but won't hold my breath. If it's no-go then 6082 will have to be used and fingers crossed it'll hold together.

Cheers

GW

[JasonBModerator @jasonb]

I have a feeling 6082 T6 has a higher tensile strength than the same temper 6061.

EDIT my feeling was right

 

Edited By JasonB on 13/10/2019 17:13:38

[john feeneyParticipant @johnfeeney58965]

Hi Graham,

As said by Jason 6082 T6 is of higher tensile strength than 6061. In all other properties they are virtually identical. In terms of performance the Nalon Viper was not of such performance that would need any kind of so called "high strength.

Regards<

John

[Graham Williams 11Participant @grahamwilliams11]

Just another question then. Was 6082, or same spec different identifier, not available or not readily available when the Viper was designed to 'take-on' the best engines of the day, presuming that's the Olivers and ETAs.

Cheers

GW

[JasonBModerator @jasonb]

May have been that the drawings were done in the states as they tend to use 6061 far more than in the UK. The link I posted also suggest 6082 is newer.

[EmgeeParticipant @emgee]

Posted by Graham Williams 11 on 13/10/2019 17:20:28:

Just another question then. Was 6082, or same spec different identifier, not available or not readily available when the Viper was designed to 'take-on' the best engines of the day, presuming that's the Olivers and ETAs.

Cheers

GW

Graham, Olivers, ETA's and many other top performance motors of that era had castings for the case which usually provided good support for the running components.

As others have said IMO 6082T6 has the strength you need for the engine mentioned but if you want something with a better spec try 2014A (HE15), usually available at M-metals. Cost of this will be more than either of the other options.

Emgee

[JasonBModerator @jasonb]

Posted by Emgee on 13/10/2019 18:15:28: Cost of this will be more than either of the other options.

Emgee

It certainly will, that's why I tend to just use it for conrods.

[Graham Williams 11Participant @grahamwilliams11]

Material specs and applications can be a minefield for the home machinist. The Viper was designed and sorta developed by one Norman Long in this country. He was involved after the war I believe in the company making YULON engines in Birmingham so not American though the drg spec is 6061 TO43 or 2024 and 2130 steel for the crank (will use EN24T) which I think are American specs. Will try Aalco tomorrow and see what their response is, if it's what I expect, will go as you suggest and use 6082, HE15 is just to expensive and I only use it for con-rods as Jason says.

Cheers

GW

[Roy VaughnParticipant @royvaughn26060]

Apologies for slightly re-purposing this thread but it seems appropriate given its title, where can I get hold of Nalon Viper plans? I feel that I should be able to locate them but searching has come up with nothing. I know they were sold by Motor Boys but not sure where they went after Ron Chernich left us. Thanks in advance, Roy

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Roy Vaughn on 15/10/2019 21:42:34:

Apologies for slightly re-purposing this thread but it seems appropriate given its title, where can I get hold of Nalon Viper plans? I feel that I should be able to locate them but searching has come up with nothing […]

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**LINK**

http://www.adriansmodelaeroengines.com/catalog/main.php?cat_id=214

MichaelG.

[Kiwi BlokeParticipant @kiwibloke62605]

Compared to 6061, 6082 is a newer and somewhat superior general-purpose alloy. My understanding is that, for most purposes, they are interchangeable. Here in backward NZ, as in USA, 6061 is the default alloy, and I haven't found a supplier of HE15-equivalent. "Tooling plate' 7075 is available, but I'm not sure why, and it isn't a substitute for 2014 / HE15. Perhaps 6061 (or something with '6061' printed on it, supported by 'certification'  pours out of China, so is cheap… Excuse my cynicism.

(Edited to remove damned stupid winking smiley. Isn't it time this bug were fixed?)

Edited By Kiwi Bloke on 16/10/2019 02:47:59

[Graham Williams 11Participant @grahamwilliams11]

6061 was a no go with the local high spec supplier so picked up an offcut of 6082 sufficient to make 2 crankcases at an affordable price so going with that for the rest of the engine. Seems more interest in the Nalon in recent years than there was when it was designed lol.

Thanks everyone for your input.

Cheers

GW

[EmgeeParticipant @emgee]

Hi Kiwi Bloke

7075 is an excellent material with a better spec than either 6061 or 6082 but at greater cost and not so widely available.

Emgee

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Kiwi Bloke on 16/10/2019 02:46:25:

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(Edited to remove damned stupid winking smiley. Isn't it time this bug were fixed?)

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Sadly … There is no bug to fix

It’s simply a matter of choice whether or not the relevant “auto-correction” feature is switched ON or OFF.

Those in control of this forum have elected to have it switched ON.

MichaelG.

[Kiwi BlokeParticipant @kiwibloke62605]

I need to correct my previous post. 7075 does seem to be a reasonable substitute for the high-strength alloy 'Dural', aka HE15, or 2024 (or 2014?). I had thought that it had inferior fatigue characteristics, but its mechanical properties seem just a little better than those of 2024 and its corrosion resistance is much better. Apologies for any confusion caused.

[Michael GilliganParticipant @michaelgilligan61133]

Perhaps the ‘original sin’ can be identified as the convenient use of the name Dural

In the years following WWII [by which time ‘Dural’ was being mis-used, in the same way that we mis-use ‘Hoover’ or ‘Loctite’] the model engineering community seems to have adopted the word.

Wikipedia has quite a good page about Duralumin and related alloys.

MichaelG.

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Edited for clarity … I hope.

Edited By Michael Gilligan on 17/10/2019 09:11:45

[Ramon WilsonParticipant @ramonwilson3]

Hello Graham – I don't post very much these days but always willing to help another engine maker when I can.

All the 5cc engines I have made so far have had all major ali parts from 6082 (He30) . This machines very easily, takes a good thread and, if required, anodises well. As already said and like Jason I only use a higher strength – 7075 or He 15 for the conrods.

I have a scaled 5 cc Nalon Viper 'on the cards' – the cases are made, as said, from 6082 which I'm confident will be more than strong enough.

The Model Engine Boys drawings were done by Model Engine News owner Ron Chernich from, I believe, an original engine – I would assume he called out the spec on the case parts to suit his views. Personally I would not have thought a higher strength than 6082 would be necessary for the case parts even if the engine is to be used in the team race environment as originally intended but of course if you have the material then why not.

I have just looked for 6061 on ebay – there is plenty of choice at reasonable cost but it appears to be mainly round section.

Hope that helps some – good luck with your Viper – is it destined for a vintage T/R BTW?

Regards – Ramon (aka Tug)

[Graham Williams 11Participant @grahamwilliams11]

Hello Tug. Been an admirer of your work for ages, I'm sure your Viper will be superb as all the others. 6082 is what I'm using now it does machine nicely so with the views posted here I'm sure that it'll work out ok. Not destined for a model it's just an excercise to keep me active since I retired, refurbed a few engines and made a BollAero which is now running and when I saw the plans for the Nalon reminded me of the Mk 1 ETA15d I used in FAI power models in my younger days. If it runs then I'll be happy though usually to get the fit of the liner/piston/contra correct it takes a few goes, still learning about the lapping process though I've had some excellent advice and a demo on the methods used from a really knowledgeable guy who lives quite close to me. We'll see how it goes and if it's a success will move on to another one that takes my fancy from the MB book.

Cheers

Graham W

[Bill PudneyParticipant @billpudney37759]

I made a couple of Nalon Vipers a year or so ago, there is a photo of my Mk1 in an album. I used 6061 T651 for the front bearing housing, fins and rear backplate, 2014 T3 for the crankcase, 4140 steel for the crankshaft, meehanite for the pistons, 12S14 (similar to leaded EN1a) for the liner, 2024 T3 for the conrod, delrin for the rotary disc. Please forgive the furrin material specs, but I'm in Australia and most of our metal comes in American specs.

Incidentally 2024 T4 or better is usually recommended for conrods, and it is certainly very good, but it's also expensive, I once was quoted US$40 for a 24" length of 1/2" diameter bar which I found (just) acceptable, but it was US$120 postage from America!! The reason that 2024 is often stated as the preferred material was because of its better properties at elevated temperatures. So I investigated and proved to my satisfaction that 7075 T651 was ALMOST as good, except for a tiny drop at fairly high temperatures, around 200 degrees C if I remember. The big advantage was that my local supplier could supply 1/2" bar at about AUS$20 a meter!!

best of luck!!

cheers

Bill

[Graham Williams 11Participant @grahamwilliams11]

Bill. As you've made a couple of Vipers could I ask whether you used a press in crank pin or machined it from the solid, also Ron Chernich's description gives a hard chromed, presumably press fitted, crank pin size of 7/32" dia but the drawings I have show 3/16" dia.and con rod to suit. Also you've used EN1A equivalent for the liner, I was going to follow the drawings which show cast iron but it's a dirty metal, and steel would be better from the point of view of keeping my lathe 'cleaner' .

Cheers

Graham W.

[Ramon WilsonParticipant @ramonwilson3]

Hi Graham,

Thanks for your compliment – appreciated.

Your approach is very much as my own in that mine are just ME projects though having recently returned to C/L flying I do have intentions of fitting at least one of them to a model in due course.

With regards to liner material I have only done one from cast and one from a very tough steel. Cast is fine of course and makes for ease of machining but does make for not only the mess on the lathe but for a very messy exhaust residue for quite some time. After I read an article on using leaded steel for liners with cast pistons things much improved both from a lapping process and piston/liner fit. All subsequent engines have been done as such and compression is very acceptable. The wear properties of En1a in cast is very good so I don't harden anything though another engine builder Dick Roberts told me he case hardens his En1a liners by filling the liner with Kasenite and heating thouroughly. Personally, though he assured me he had not experienced it, I would not risk the potential for distortion. I don't know if you've seen any of the build logs I posted on Model Engine Maker but if not that might be worth a look as this subject is covered in depth.

I have only ever fitted one press fitted crankpin – an Eta15d converted to the Stockton/Jehlik specs. This was for Mike Crossman and destined for a T/R – I've never heard anything on how well it performed so can't comment but I do know someone who fits all his 3.5cc engines for use in combat flying with crankpins made from needle roller bearing rollers with great success. All the crankshafts in the 5cc versions have been made from En24T with the pin turned as part of the web.

Bill's comment on the 7075 is warranted – I use a material called Alumec 89 but supplies are very limited now as my source has retired! It came from a local factory and was off cuts from material used for making moulds for blow moulding. A very tough ali which has stood up to the task well.

I'll look forwards to seeing yours run – I still get a buzz from firing one of mine up. In the meantime if I can be of help I'll be glad to.

Regards – Tug

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