Nalon Viper 2.5cc CI Engine

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pat_pending

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Also, forgot to ask, any tips on balancing props? Drilling out the centre here to fit the Nalon prop nut to 7.5mm might have added 0.5mm runout! I was thinking of mounting in the lathe on some sort of arbor and taking light skims off the end of the blades at a high RPM and sharp tool. Thinking there might be some better way
 

Ramon

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APC props are very efficient in use - they are also extremely efficient slicing through flesh as quickly as a scalpel either as you percieve, running your finger down the edge as you flick a flooded engine or if you catch your fingers in the prop arc. Believe me you will not be the first :rolleyes:

I always sand both edges of new props to take that sharp mould line off - particularly so the trailing edge for that very reason. Only recently I sliced into my right index finger near down to the bone on a friends untreated prop so always treat any moulded prop and particularly the glass filled nylon or carbon props with respect. I've never used a chicken stick nor one of those rubber finger protectors but I do use an old stout leather gardening glove. Regretably I was not wearing it at the time mentioned.

Probably a better general prop would be a Master or Graupner Standard though the latter do tend to be a bit on the heavy side. Best of all for your purpose is wood but they are getting very difficult to find in the sub 10" diameter range.

Keeping to a specific size does help - there's quite a lot that can be recyled especially exp. mandrels and laps.

All the best with whatever you do in future Pat - you've persevered here and shown you have what it takes - so go right on and go for it👍👍

Tug
 

Ramon

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Also, forgot to ask, any tips on balancing props? Drilling out the centre here to fit the Nalon prop nut to 7.5mm might have added 0.5mm runout! I was thinking of mounting in the lathe on some sort of arbor and taking light skims off the end of the blades at a high RPM and sharp tool. Thinking there might be some better way

Definitely don't do as you describe - the blades would probably shatter.

You need to get your self a prop balancer or make a simple one - length of steel that fits the prop hub tightly. Cone each end of the steel to a sharp point about 60* inclusive

Insert through prop with equal amount protruding each side and support on the points between finger and thumb.

Sand the tip back on the heavier blade until near true then sand the back of the blade to fine tune.

There are several balancers available with very varying prices but in the end they all do the same thing. I have use the humble injection moulded one below from SLEC for years - still works for me.

Tug


 
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Mechanicboy

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Don’t want anything overheating!
Model diesel engine does not run hotter than glow plug engine and the engine is over lubricated (25-33% oil in fuel) that the oil conducts heat away from the engine and ensures that the engine runs well lubricated. :)
 

pat_pending

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Awesome.

Now you need to build a plane around it 🤠

David
Hey David, hope you're keeping well. Yeah, 'great minds think alike' and all that, I've got one of these on order:


Patrick
 

Ramon

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Hey Pat - you never said you were a control line flyer - been a passion with me for over sixty years. Building a largish stunt model right at the momenmt - 'Coy Lady' - ring any bells?

If you want a similar looking but brilliant flyer get yourself a 'Frog' Talisman plan and get it scaled to 42" wingspan. I had one with an Olly in it - great combination.

Tug
 

pat_pending

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Hey Pat - you never said you were a control line flyer - been a passion with me for over sixty years. Building a largish stunt model right at the momenmt - 'Coy Lady' - ring any bells?

If you want a similar looking but brilliant flyer get yourself a 'Frog' Talisman plan and get it scaled to 42" wingspan. I had one with an Olly in it - great combination.

Tug
Hi Tug, I'm not currently but have always wanted to give it a go. I love the whole niche/vintage aspect to it too. Also, i get SOOOOO bored of me showing people engines only for them to look at me confused and say either "what are you going to power with it" or "couldn't you make an electric one" and all that stuff :) Im sure you know what I mean. This time I can say it's for a plane and cut the conversation short LoL.

Thanks for the tip on the Frog. I'll take a look. If there are any decent 'getting started' resources you could point me too that would be much appreciated.

Patrick
 

Ramon

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Well I hear your sentiment but if this is to be a first you really need someone to show you how to fly. Believe me it is not a matter of holding the handle and bending your wrist up to go up and down to go down. Everything from the point of launch will happen so fast you won't see it! If it follows true form the plane will go up, you will follow it with your arm (the worst thing you can do) and it will be over your head and into the ground before you can say Flite Streak.

I've shown a lot of people how to fly those first few laps over the years usually with success but you will have a pretty quick model there to begin on so theres quite a few things to keep in mind from building the model onwards. Time for that later.

Buying a kit as you have is a costly exercise at the best of times - much better to buy a plan and some raw balsa.

Heres the link to the Talisman FROG TALISMAN PLANS CONTROL LINE PROFILE STUNT | eBay - similar to the Flite streak in format there were several models of like designs.

Heres a standard 28" WS version I built a long time ago



But these are the kind of aircraft I prefer - aerobatic models of the 'classic' era (used to be '58 to '69) not sure what it is now


I still have the Thunderbird and the Nobler next to it. The other Nobler and Oriental were sold on and the Master was reduced to matchwood after a push rod failure - breaking them hurts!

Regards - Tug
 

pat_pending

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Beautiful planes Tug! I think I'll take it one step at a time and have reached out to my local model flying club for membership and to see if there's someone there who can show me the ropes/lines (excuse the pun).

I bought the flight streak off eBay with engine for £85 as a bit of an impulse buy. I think thats probably a good deal vs buying all the parts and making (or indeed a kit). I will look at the frog build if I get the 'bug'.

I'm going to take the plunge and try making those transfer passage cutters today and will report back.

Thanks,
Patrick
 

Tim Wescott

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I second the recommendation that you get help learning to fly.

Much as it pains me -- if you don't already have experience with engine handling, you should learn to fly on a plane with a factory engine. The pool of people willing to help you with engine problems will shrink dramatically if you show up as a novice pilot and you've built your own engine. Unless there's someone in the club who seems to be a good pilot and is enthusiastic -- then go for it.
 

xpylonracer

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Pat
The best advice I received when starting to fly control line was with the control handle vertical with the "up" line at the top lock the wrist at neutral and keep the arm straight, point your arm where you want the model to fly.

Marcus
 

Ramon

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Yep, that's the technique but there's a little more to add which I feel is best left until right before that first attempt.

Currently at the moment going through the moves with someone who last flew 50 years ago - so far so good ;) and just started inverted flying.

Tug
 

Tim Wescott

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If you're a courageous teacher, on the first few flights put the handle in your student's hand, then grab that assembly with your hand and fly the plane through your student's hand. When you feel they've got the hang of it, let go, lie down, and watch how they do.

If your hands aren't big enough for that, make a double handle so that you can both hold on.

Short-tanking the plane until the student doesn't get dizzy is a good idea, too.
 

Ramon

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Never quite thought of it that way Tim but looks like I might be a 'courageous teacher' Ha Ha !

I've been doing it that way for years - young and old - but Pat's a fair distance away, I'll step in only if he can't find anyone locally which is what he really needs.

Of course he could always jump in his car and visit us for first hand treatment - we certainly won't be put off by the fact he has built his own engine ;)

Are you a regular C/L flyer? Any preferences?

Tug
 

Tim Wescott

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"Are you a regular C/L flyer? Any preferences?"

I fly stunt in the US Pacific Northwest. I'm not sure if you're familiar with the AMA events, but I fly in Expert. I have been placing in the middle of the pack, but I'm currently working at a startup, and haven't practiced in a good long while.
 

Ramon

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Hi Tim, yes familiar with AMA stunt. Though lapsed now I was a PAMPA member for several years. My first Stunt News was a few pages just before Tom Morris turned it into the epic magazine it became. I no longer compete - last time was 2006 and am just getting back into C/L again after quite a long lay off. Sadly I let all my SN go.

Always had a predominent liking for the American designs especially of the Classic period. Yet to build my real desire - a Tucker Special - but there's just about time left. Currently building a British design 'Coy Lady' for a Stalker 40 an engine. I've had that for many years but it is yet unused. At 76 there's not much time left but what there is I intend to make the most of it.

Regards - Tug
 

pat_pending

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Thanks yet again for all the good advice guys. I'l certainly get tuition and use a commercial engine until I well and truly know what I'm doing!

Patrick
 

pat_pending

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Had a bit more shed time yesterday and completed Viper #2. This one seems to run a fraction stronger than the other one but only by a fraction.

Here is a video of her running after a few breaking in runs (propeller on the right way this time I hope :) ). I have a solution for a finger-guard figured out involving 10 layers of duct tape too :)


The only issue with this one is that the compression screw auto-unwinds it's self when the engine is over 11K RPM or so. The contra piston might be a fraction too loose a fit (although I thought it was really tight). The margin between too tight and too loose on these engines really is measured in 10's of atoms!

Tug - I didn't get round to trying your transfer passage technique or use the fixture and cast iron you sent me to make the crankshaft. That will be the #3 Viper for which I have 60% of the parts in the box.

I start a new job tomorrow so it will be slow-going in the workshop for a while but super happy to get these two 'off the bench' before.

Building these have been really fun. Starting to ponder the next challenge.

Taks care,

Patrick

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