Norvel .15 Big Mig, again
02-17-2010, 06:19 PM
#26
Senior Member
RE: Norvel .15 Big Mig, again
My remarks about prop size are relevant to glow engines that most people have rather than the one off diesels that a few play with. This thread is about the glow Norvel .15, which I would start out with a 7-5 and work down towards a 6-6 until I stopped seeing substantial RPM gains with each drop in size or a reduction in in-air performance.
Re: the Picco, from your vids the props you ran were too big to get to where the Picco makes it's power as a glow engine. A 6-3 prop on ANY modern 1/2A is too big, even for a Big Mig .061. I doubt you could put a small enough prop on a Picco to get it to turn up like it does in a car. A 3-3 would probably do it but not have enough flywheel mass to get the engine started.
Diesels are totally different because the prop size efficiency from a 5" prop to an 8" prop is probably greater than the horsepower difference. Put a gearbox on that Picco and see how fast it swings an 8-4!
Re: the Picco, from your vids the props you ran were too big to get to where the Picco makes it's power as a glow engine. A 6-3 prop on ANY modern 1/2A is too big, even for a Big Mig .061. I doubt you could put a small enough prop on a Picco to get it to turn up like it does in a car. A 3-3 would probably do it but not have enough flywheel mass to get the engine started.
Diesels are totally different because the prop size efficiency from a 5" prop to an 8" prop is probably greater than the horsepower difference. Put a gearbox on that Picco and see how fast it swings an 8-4!
02-17-2010, 08:24 PM
#27
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RE: Norvel .15 Big Mig, again
ORIGINAL: DeviousDave
My remarks about prop size are relevant to glow engines that most people have rather than the one off diesels that a few play with. This thread is about the glow Norvel .15, which I would start out with a 7-5 and work down towards a 6-6 until I stopped seeing substantial RPM gains with each drop in size or a reduction in in-air performance.
Re: the Picco, from your vids the props you ran were too big to get to where the Picco makes it's power as a glow engine. A 6-3 prop on ANY modern 1/2A is too big, even for a Big Mig .061. I doubt you could put a small enough prop on a Picco to get it to turn up like it does in a car. A 3-3 would probably do it but not have enough flywheel mass to get the engine started.
Diesels are totally different because the prop size efficiency from a 5'' prop to an 8'' prop is probably greater than the horsepower difference. Put a gearbox on that Picco and see how fast it swings an 8-4!
My remarks about prop size are relevant to glow engines that most people have rather than the one off diesels that a few play with. This thread is about the glow Norvel .15, which I would start out with a 7-5 and work down towards a 6-6 until I stopped seeing substantial RPM gains with each drop in size or a reduction in in-air performance.
Re: the Picco, from your vids the props you ran were too big to get to where the Picco makes it's power as a glow engine. A 6-3 prop on ANY modern 1/2A is too big, even for a Big Mig .061. I doubt you could put a small enough prop on a Picco to get it to turn up like it does in a car. A 3-3 would probably do it but not have enough flywheel mass to get the engine started.
Diesels are totally different because the prop size efficiency from a 5'' prop to an 8'' prop is probably greater than the horsepower difference. Put a gearbox on that Picco and see how fast it swings an 8-4!
Some interesting comments about props above. The Cox 8x4 was regarded as being underpitched IIRC when they were in common use. Carbon Fibre single blade props are used in Australia on converted .11 and .12 CI car motors to make them run in their power bands. They are available commercially. I can post a pic if you're interested.
A suitable standard prop could be converted to single blade for a high reving .061 with a bit of experimentation. There are some articles on the topic on the Supercool Propeller web site.
Ray
02-17-2010, 11:46 PM
#28
RE: Norvel .15 Big Mig, again
There are still a few of us who choose the prop we need for a plane and stuff an engine that can do the job in the middle. 
I guess whether the NORVEL Big Mig or AME .15 can do the job depends on what you are flying. Not all need peak performance.
I like mine, but then I'm a sport flyer.
George
I guess whether the NORVEL Big Mig or AME .15 can do the job depends on what you are flying. Not all need peak performance.
I like mine, but then I'm a sport flyer.
George
06-10-2011, 11:57 AM
#29
RE: Norvel .15 Big Mig, again
I ran a Norvel .15 (AME) today and got 17900rpm on an APC 7x4 10% Nitro. The step in the exhaust port has been removed, but I haven't looked for a larger carb. It feels like the engine is just a nice and timid sports engine rather than a screamer. On an APC 8x4 I got 14400rpm and a reliable tick over at 2200rpm, quite impressive low end actually.
I have an SC .15XLS that runs much better on the APC 7x4, top revs are around 19700rpm (with stock muffler) and it has a nice scream to it.
I think have a plane that I can put after the SC engine and 7x4 prop (a shoestring), guess I need to build something slower to attach behind the Norvel then...
I have an SC .15XLS that runs much better on the APC 7x4, top revs are around 19700rpm (with stock muffler) and it has a nice scream to it.
I think have a plane that I can put after the SC engine and 7x4 prop (a shoestring), guess I need to build something slower to attach behind the Norvel then...
07-27-2011, 10:23 AM
#30
RE: Norvel .15 Big Mig, again
Okay, I think I've found a simple fix for the Norvel .15 now. I put on a carb from an MVVS .15 and it now spins an APC 8x4 at about 15800 rpm and still idles down to about 2800rpm.
That's an healthy 1400rpm increase compared to the stock carb and even an 800rpm advantage over the ASP .15XLS on the same prop and fuel. In terms of hp/kg it now approaches a factor of 2, which is similar to what the smaller Norvel engines are producing too.
The MVVS carb is a direct drop-in and only has a slightly larger inner bore than the stock carb (5.5 mm compared to 5.0), but there is a large difference in the area as the Norvel also has the very bulky spraybar and second needle, while the MVVS is an airbleed carb.
That's an healthy 1400rpm increase compared to the stock carb and even an 800rpm advantage over the ASP .15XLS on the same prop and fuel. In terms of hp/kg it now approaches a factor of 2, which is similar to what the smaller Norvel engines are producing too.
The MVVS carb is a direct drop-in and only has a slightly larger inner bore than the stock carb (5.5 mm compared to 5.0), but there is a large difference in the area as the Norvel also has the very bulky spraybar and second needle, while the MVVS is an airbleed carb.
07-27-2011, 06:44 PM
#31
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RE: Norvel .15 Big Mig, again
ORIGINAL: Mr Cox
Sounds like good numbers to me, the old MAS 7x4 is a pretty high load prop too...
What does the Magnum/ASP 15XLS do on the same prop?
Sounds like good numbers to me, the old MAS 7x4 is a pretty high load prop too...
What does the Magnum/ASP 15XLS do on the same prop?
07-27-2011, 07:59 PM
#32
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RE: Norvel .15 Big Mig, again
That's an amazing result,,,, good work. As I recall, the Norvel .25 throttle is also a drop in for the .15,,, worth a try. Going to do that soon as I get the shop back to the way it was.
07-28-2011, 05:34 AM
#34
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RE: Norvel .15 Big Mig, again
Here's the .15 as a diesel with an OS .10 muffler attached. Diesels tolerate smallish mufflers so this worked well. Point is how I attached the muffler. The crankcase has to be milled square at the exhaust location. A clamp and two screws hold it on. The outlet of the Norvel isn't an exact match, the OS muffler's intake is long and narrow so a gasket made of Teflon is used. Not the best solution, the Teflon is soft and eventually distorts after a time giving you a leak. A good, firm, asbestos type gasket material would be better.
http://www.youtube.com/user/hopeso#p/u/78/PtDuF1ECAuM
I have an OS .15 muffler but the mismatch is too much for a gasket to handle. I think an MVVS muffler might do the trick as I recall their engine's exhaust outlet was more squarish similar to Norvel's.
http://www.youtube.com/user/hopeso#p/u/78/PtDuF1ECAuM
I have an OS .15 muffler but the mismatch is too much for a gasket to handle. I think an MVVS muffler might do the trick as I recall their engine's exhaust outlet was more squarish similar to Norvel's.
07-28-2011, 06:35 AM
#35
Senior Member
RE: Norvel .15 Big Mig, again
The MVVS's .15's muffler has a round outlet for a 1/4 wave pipe, I think the later 1.5cc engines had a bolt on muffler with a rectangular exhaust outlet. Earlier 1.5cc motors from them had a clamp on setup.
07-28-2011, 09:04 PM
#36
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RE: Norvel .15 Big Mig, again
Interesting to read all this - I bought a pair of these because the Australians like the engine for their CL plain bearing .15 racing classes. Haven't run mine yet.
Iskandar
Iskandar
07-29-2011, 12:12 AM
#38
RE: Norvel .15 Big Mig, again
Sorry, I only have one of the .21 MVVS engines and the tuned muffler to go with it. It looks like it could be made to fit, although the screw are not quite far apart enough to clear the case.
The Irvine .20 muffler looks like a good candidate too, but it has the same problem with slightly too closely spaced screws.
The Irvine .20 muffler looks like a good candidate too, but it has the same problem with slightly too closely spaced screws.
07-29-2011, 05:31 AM
#39
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RE: Norvel .15 Big Mig, again
Thanks Mr Cox,
In fact, what I'd do is after milling the top of the engine case square, (where the exhaust port is) I'd make up an exhaust header to fit and JB Weld it on so bolt spacing isn't the problem. It's the shape of the exhaust port needing to be more square than long and thin as is typical of OS, (and many others).
I guess it's *%$#Bay time. [:@]
In fact, what I'd do is after milling the top of the engine case square, (where the exhaust port is) I'd make up an exhaust header to fit and JB Weld it on so bolt spacing isn't the problem. It's the shape of the exhaust port needing to be more square than long and thin as is typical of OS, (and many others).
I guess it's *%$#Bay time. [:@]
08-11-2011, 05:19 AM
#41
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RE: Norvel .15 Big Mig, again
Diesel with a 10 x 4 prop at 11K. A Magic Muffler is tuned, isn't it? Good for glow, not for diesel? Or can it be tuned for lower RPM?
08-11-2011, 06:16 PM
#42
RE: Norvel .15 Big Mig, again
I don't see any reason why you could not make one tuned for 11k, but it would be kinda long! (25cm)
It would be fun to try though, and of it didn't work, it could be shortened to be the muffler by trimming the header.
It would be fun to try though, and of it didn't work, it could be shortened to be the muffler by trimming the header.
08-11-2011, 06:41 PM
#43
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RE: Norvel .15 Big Mig, again
Well, I've been thinking about how a diesel would respond to a tuned pipe. Of course you'd need to build it to suit the expected RPM and then there's throttling.
Just slapping a tuned pipe on to a VA MK2 delivered a decent, 1.5K with no attention paid to pipe timing and such. Good throttling was retained.
The MK2 ran well as a diesel even with some serious timing changes (by mistake) and the crank held up fine. The MK1 not so good. both have a straight back exhaust so it's time, I guess, I took a stock MK2 and ran it as a diesel on a pipe. But right now I'm involved in some serious backyard landscaping projects. It may not be till October before I get around to flipping props on the bench.
Just slapping a tuned pipe on to a VA MK2 delivered a decent, 1.5K with no attention paid to pipe timing and such. Good throttling was retained.
The MK2 ran well as a diesel even with some serious timing changes (by mistake) and the crank held up fine. The MK1 not so good. both have a straight back exhaust so it's time, I guess, I took a stock MK2 and ran it as a diesel on a pipe. But right now I'm involved in some serious backyard landscaping projects. It may not be till October before I get around to flipping props on the bench.
08-13-2011, 06:30 AM
#44
RE: Norvel .15 Big Mig, again
Hi Japanman!! i've read this whole thread and noticed one post about the AME .15 I have a new one in the box I got as part of a trade going from bigger stuff to smaller stuff. Had it out of the box once and have a plane in mind for it.......could you please tell me if its a pretty good r/c engine?? in respect to an above average flyer, builder, tuner and modeler?? sure would appriciate any words of wisdom??
thanks, bill
thanks, bill
08-13-2011, 07:13 AM
#45
RE: Norvel .15 Big Mig, again
It is a very nice sport engine that throttles and idles well. It is just lower in power (with the stock carb) than what one would expect from a Norvel engine. As the smaller ones are dominating the field in terms of power over weight. There is nothing wrong with that, it is just a bit uncharacteristic. It would have been if they would also offer a full-out racing version though, it would only require a different carb and possibly exhaust.
08-13-2011, 07:40 AM
#46
RE: Norvel .15 Big Mig, again
thanks Mr Cox!! that is just the info i was looking for.......its going to be used for sport flying and i'm not concerned about the output
thanks again, bill
thanks again, bill
08-14-2011, 03:01 AM
#47
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RE: Norvel .15 Big Mig, again
ORIGINAL: Mr Cox
It is a very nice sport engine that throttles and idles well. It is just lower in power (with the stock carb) than what one would expect from a Norvel engine. As the smaller ones are dominating the field in terms of power over weight. There is nothing wrong with that, it is just a bit uncharacteristic. It would have been if they would also offer a full-out racing version though, it would only require a different carb and possibly exhaust.
It is a very nice sport engine that throttles and idles well. It is just lower in power (with the stock carb) than what one would expect from a Norvel engine. As the smaller ones are dominating the field in terms of power over weight. There is nothing wrong with that, it is just a bit uncharacteristic. It would have been if they would also offer a full-out racing version though, it would only require a different carb and possibly exhaust.
There's an alternative view here.
Norvel 15's were developed for control line application where they are outstanding.
The r/c market is biased toward a consumerist low skilled/low tech user base. Allow the engine to breath and play with the head and you can unleash it's power.
Fitting it with a muffler destroys it potential right off.
08-14-2011, 05:18 AM
#48
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RE: Norvel .15 Big Mig, again
Allow the engine to breath and play with the head and you can unleash it's power.
Fitting it with a muffler destroys it potential right off.
EG
08-14-2011, 05:21 PM
#49
RE: Norvel .15 Big Mig, again
Thanks for the alternative info!!! I have a long history of "massaging" mechanical things , and port timing is one of them, along with valve timing, race engine building, way out of the box work......i'll take a look and check the port timing against some other engines i've run, both in control line and r/c.....check the head, run it and check the burn pattern......muffler is optional, but i already wear hearing aids from years fo abuse..
thanks for the heads up!! bill
thanks for the heads up!! bill
08-14-2011, 05:38 PM
#50
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RE: Norvel .15 Big Mig, again
ORIGINAL: eroc144
Would love to read about any tips / tricks you've used!
Not sure about others, but no muffler means no flying at my field due to noise restrictions.
EG
Allow the engine to breath and play with the head and you can unleash it's power.
Fitting it with a muffler destroys it potential right off.
EG
In my club we've been boring out the AME cylinder and fitting a Rossi 15 "Normale" piston/liner/and rod. Timing bore/stroke and conrod length is the same in both engines. A Rossi head button can be made to fit as well.