Norvel .074 on a tuned pipe
07-11-2012, 09:22 PM
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Norvel .074 on a tuned pipe
With Japanman's help, I was able to put a CS pipe on the Norvel .074 on my Tsunami. It was good but not like the original, .40, piped version. Stock, the Norvel .074 delivered 16K on 25% fuel and the Cox 7 X 3.5 prop. Many will suggest that I'm over propped and I'd not disagree. Yet, my experience has been that though the Cox prop slows the engine, compared to the 7 X 3 APC, at least on the Tsunami, the Cox prop delivers better performance.
A run with the proper bits can be seen here. http://www.youtube.com/watch?v=7lM9f...aTo&playnext=1
But as related, the pipe gets set too far from the fuse to secure it properly. On a whim, I tried this. http://www.youtube.com/watch?v=F6Hqd...hannel&list=UL I used the stock muffler as the pipe header. Despite the rather dirty exhaust flow, I lose only 500 RPM. I'll take it. My thrust/HP calculator says that 17.5K on a 7 X 3.5 puts out 32 ounces of thrust and .322 HP. All up weight with the pipe is 24 ounces.
It should be mentioned that a CS throttle was used instead of the stock throttle. Stock, the bore of the barrel is 3mm and the CS barrel is 4.5mm. This proved to present some idling problems so the bore was reduced to 4mm.
Acceleration is s bit ratty but we've found that this can go away in the air. We'll see and hope to post a flight video as time permits.
A run with the proper bits can be seen here. http://www.youtube.com/watch?v=7lM9f...aTo&playnext=1
But as related, the pipe gets set too far from the fuse to secure it properly. On a whim, I tried this. http://www.youtube.com/watch?v=F6Hqd...hannel&list=UL I used the stock muffler as the pipe header. Despite the rather dirty exhaust flow, I lose only 500 RPM. I'll take it. My thrust/HP calculator says that 17.5K on a 7 X 3.5 puts out 32 ounces of thrust and .322 HP. All up weight with the pipe is 24 ounces.
It should be mentioned that a CS throttle was used instead of the stock throttle. Stock, the bore of the barrel is 3mm and the CS barrel is 4.5mm. This proved to present some idling problems so the bore was reduced to 4mm.
Acceleration is s bit ratty but we've found that this can go away in the air. We'll see and hope to post a flight video as time permits.
07-12-2012, 07:43 AM
#2
RE: Norvel .074 on a tuned pipe
I figured unscientifically that the pipe should be on song at about 20,000 rpm.( or 40,000) You have an extension so maybe a bit lower. It may pick up rpm's in the air and improve. Pipes like to be rich so a carb is likely never going to get an idle, transition, and high speed perfect. Was the rpm the same without a pipe or muffler? or did it improve?
07-12-2012, 10:37 AM
#4
RE: Norvel .074 on a tuned pipe
I had a 6-3.5 on my .074 Big Mig and it went 18,900 rpm. Couldn't believe how rock solid it was. Idled well, revved up great, insensitive needle setting, which could mean room to go for a bigger carb. but was still great to be that way. A pipe would bring it up maybe over the 20,000 rpm. A dive on the 7-3 or 7-3.5 might get it on the pipe too maybe. Needs testing I guess, as was mentioned. I bought mine used to replace a Queen Bee, but then got the Queen Bee going good anyway, so the Norvel needs another project. Looks like a good one.
07-12-2012, 01:41 PM
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RE: Norvel .074 on a tuned pipe
What did you do to get the Queen Bee to perform? A lot of people on this forum consider them one of the worst engines Cox made-so it would be of interest to hear any tricks you used. I've always thought them nice looking but fairly gutless........
ChrisM
'ffkiwi'
ChrisM
'ffkiwi'
07-12-2012, 01:55 PM
#6
RE: Norvel .074 on a tuned pipe
Something on the tank system was plugged in the plane. That is why it wouldn't run. On the test stand it worked good. The 6-3.5 prop went 15,400 rpm. compared to 18,900 of the norvel. It has to be remembered it is a reedy, and the plane I used it on was just for piddling around that was designed for an .049. The tach reading was without the muffler which is what most .049's would have been not using for comparison. It isn't that much different than say the Thunder Tiger .07 but it isn't a ball of fire either. The Norvel is quite good for comparing anything to. The .15 really amazed me when I was told to open up the carb. and I made a control line carb for it.
07-12-2012, 02:24 PM
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RE: Norvel .074 on a tuned pipe
ORIGINAL: aspeed
I figured unscientifically that the pipe should be on song at about 20,000 rpm.( or 40,000) You have an extension so maybe a bit lower. It may pick up rpm's in the air and improve. Pipes like to be rich so a carb is likely never going to get an idle, transition, and high speed perfect. Was the rpm the same without a pipe or muffler? or did it improve?
I figured unscientifically that the pipe should be on song at about 20,000 rpm.( or 40,000) You have an extension so maybe a bit lower. It may pick up rpm's in the air and improve. Pipes like to be rich so a carb is likely never going to get an idle, transition, and high speed perfect. Was the rpm the same without a pipe or muffler? or did it improve?
Here, http://www.youtube.com/watch?v=lrOTQv1YUIE we have this engine spinning a 7 X 3 APC at 19.3K. No attempt was made to fine tune the pipe length for the time being. We are just poking at the concept as a starting point.
Next up is the 7 X 4 APC and it did 16.4K. We lengthened the pipe an extra 1/2" and the result was a 1.5K gain. Will get some longer tubing and try again. More to come.
07-31-2012, 07:33 AM
#9
RE: Norvel .074 on a tuned pipe
Andy,
Where can I get the header & pipe for the Norvel .074? Mine, with stock muffler, is only doing slightly over 15,000 on apc 7x3, and 30% nitro. I'm very disappointed with the performance of this engine. RS
Where can I get the header & pipe for the Norvel .074? Mine, with stock muffler, is only doing slightly over 15,000 on apc 7x3, and 30% nitro. I'm very disappointed with the performance of this engine. RS
07-31-2012, 08:26 AM
#11
RE: Norvel .074 on a tuned pipe
It is a fairly big prop at 7". Try a 6-4 or so. I think it would respond well to a larger venturi. Maybe a control line venturi on pressure would be good, especially with a pipe, or no muffler at all. Of course there would be no idle. Andy used the bigger CS carb on his. I thought mine was quite good compared to anything else available using a smaller prop. The newer motors like to rev a bit more than before.
07-31-2012, 03:52 PM
#13
RE: Norvel .074 on a tuned pipe
I'm a big fan of the 6.3X4 on the .074, but the 7X3 works good on heavier, slower planes too.
RS, how many head shims are you running and how much fuel has been run through the engine? CP is right, 17,000 is norm for that combo, but it is real hot right now. I live in FL and get an extra 1,000rpm in the winter at the least, from almost all my motors.
RS, how many head shims are you running and how much fuel has been run through the engine? CP is right, 17,000 is norm for that combo, but it is real hot right now. I live in FL and get an extra 1,000rpm in the winter at the least, from almost all my motors.
07-31-2012, 04:24 PM
#14
RE: Norvel .074 on a tuned pipe
hllywdb,
I started with 3 shims, then went to two and now I'm only using one. The engine at this point has about 30 minutes run time. What is the normal break-in time for these engines? The instructions say "approximately 15 Minutes"? RS
I started with 3 shims, then went to two and now I'm only using one. The engine at this point has about 30 minutes run time. What is the normal break-in time for these engines? The instructions say "approximately 15 Minutes"? RS
07-31-2012, 08:48 PM
#15
Senior Member
RE: Norvel .074 on a tuned pipe
ORIGINAL: combatpigg
That combo should turn 17,000 stock.
These engines are sometimes too tight and need a lot of running before loosening up to run right.
That combo should turn 17,000 stock.
These engines are sometimes too tight and need a lot of running before loosening up to run right.
No kidding.... I've been running an .074 for a year and a half and am still 1k under what everyone says the prop and fuel should turn. Apparently they just up and decide to 'wake up' one day and pick up a bunch of power, can't wait.
The 6.3-4 APC seems to be meant for this engine..
08-01-2012, 05:41 PM
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RE: Norvel .074 on a tuned pipe
Not sure this is Relevant or merely a Rant :-)
Years ago (early/mid 70's) in my misspent youth I fielded factory race bikes for Yamaha. Genuine world beaters back then :-)
Rebuilt, modified and redesigned a 'few' Exp chambers in process.. Still remember a bit about them.
These were invented as Sonic devices.
Material resonance is Critical ! Ali and Carbon fibre are erm Useless at that.
Ever seen any musical instruments of either material?
Also Millimeters were critical.There is NO 'good enough' .. it's either Exact or Crap. Chamber design involves long PITA calculations and/ or a V pricey Program and still depends on Micrometer measurements
Toy airplane fitments are IMO a sad joke. They ONLY look like chambers.
Yet some dullards persist in paying large for looks alone.
PT Barnum would be proud.
A tested/developed /tuned length of ...straight ex tube ...will work 'at least ' as well .. true.
Don't Believe? spend the few weeks testing and reinventing the wheel firsthand
As an oddity factoid ; only recently was I made aware (had eyes opened) that toy 2 strokes were actually Orders of Magnitude.. less.. sophisticated and powerful than even "street' 2 stroke engines... cc vs cc despite the total lack of nitro in the gasoline fueled moto versions to add insult to injury. I had always assumed the reverse .. In complete error.
Pretty well a moot point given that only a few serious 2 stroke Bike engines currently exist especially so with the recent demise of Moto2 GP... $250K.. 250 cc race only engines tho.
Years ago (early/mid 70's) in my misspent youth I fielded factory race bikes for Yamaha. Genuine world beaters back then :-)
Rebuilt, modified and redesigned a 'few' Exp chambers in process.. Still remember a bit about them.
These were invented as Sonic devices.
Material resonance is Critical ! Ali and Carbon fibre are erm Useless at that.
Ever seen any musical instruments of either material?
Also Millimeters were critical.There is NO 'good enough' .. it's either Exact or Crap. Chamber design involves long PITA calculations and/ or a V pricey Program and still depends on Micrometer measurements
Toy airplane fitments are IMO a sad joke. They ONLY look like chambers.
Yet some dullards persist in paying large for looks alone.
PT Barnum would be proud.
A tested/developed /tuned length of ...straight ex tube ...will work 'at least ' as well .. true.
Don't Believe? spend the few weeks testing and reinventing the wheel firsthand
As an oddity factoid ; only recently was I made aware (had eyes opened) that toy 2 strokes were actually Orders of Magnitude.. less.. sophisticated and powerful than even "street' 2 stroke engines... cc vs cc despite the total lack of nitro in the gasoline fueled moto versions to add insult to injury. I had always assumed the reverse .. In complete error.
Pretty well a moot point given that only a few serious 2 stroke Bike engines currently exist especially so with the recent demise of Moto2 GP... $250K.. 250 cc race only engines tho.
08-01-2012, 06:05 PM
#17
RE: Norvel .074 on a tuned pipe
Just for interest's sake, a 3.5 cc or .21 Novarossi is putting out supposedly close to 3 hp. Over 2 anyway. Is the $250,000 250 cc bike putting out 214 hp to equal that hp/cc? I am impressed if it does. It is a lot of money for a bike. Racing teams spend a lot of cash for little improvements, and over the years the improvements add up. The FAI motors have proved this with motors compared to regular sport motors, but motorcycles and car racing have the real development money. Oh and just for the sake of argument, I have actually seen a picture of a carbon fiber guitar somewhere. Not too many 2 stroke bikes left any more. I still got a moped 2 stroke. It is fassst at 60 kph, it came with a TURBO pipe. I bet everyone is impressed.
08-01-2012, 06:25 PM
#18
RE: Norvel .074 on a tuned pipe
ORIGINAL: danilo-2
Not sure this is Relevant or merely a Rant :-)
Years ago (early/mid 70's) in my misspent youth I fielded factory race bikes for Yamaha. Genuine world beaters back then :-)
Rebuilt, modified and redesigned a 'few' Exp chambers in process.. Still remember a bit about them.
These were invented as Sonic devices.
Material resonance is Critical ! Ali and Carbon fibre are erm Useless at that.
Ever seen any musical instruments of either material?
Also Millimeters were critical.There is NO 'good enough' .. it's either Exact or Crap. Chamber design involves long PITA calculations and/ or a V pricey Program and still depends on Micrometer measurements
Toy airplane fitments are IMO a sad joke. They ONLY look like chambers.
Yet some dullards persist in paying large for looks alone.
PT Barnum would be proud.
A tested/developed /tuned length of ...straight ex tube ...will work 'at least ' as well .. true.
Don't Believe? spend the few weeks testing and reinventing the wheel firsthand
As an oddity factoid ; only recently was I made aware (had eyes opened) that toy 2 strokes were actually Orders of Magnitude.. less.. sophisticated and powerful than even ''street' 2 stroke engines... cc vs cc despite the total lack of nitro in the gasoline fueled moto versions to add insult to injury. I had always assumed the reverse .. In complete error.
Pretty well a moot point given that only a few serious 2 stroke Bike engines currently exist especially so with the recent demise of Moto2 GP... $250K.. 250 cc race only engines tho.
Not sure this is Relevant or merely a Rant :-)
Years ago (early/mid 70's) in my misspent youth I fielded factory race bikes for Yamaha. Genuine world beaters back then :-)
Rebuilt, modified and redesigned a 'few' Exp chambers in process.. Still remember a bit about them.
These were invented as Sonic devices.
Material resonance is Critical ! Ali and Carbon fibre are erm Useless at that.
Ever seen any musical instruments of either material?
Also Millimeters were critical.There is NO 'good enough' .. it's either Exact or Crap. Chamber design involves long PITA calculations and/ or a V pricey Program and still depends on Micrometer measurements
Toy airplane fitments are IMO a sad joke. They ONLY look like chambers.
Yet some dullards persist in paying large for looks alone.
PT Barnum would be proud.
A tested/developed /tuned length of ...straight ex tube ...will work 'at least ' as well .. true.
Don't Believe? spend the few weeks testing and reinventing the wheel firsthand
As an oddity factoid ; only recently was I made aware (had eyes opened) that toy 2 strokes were actually Orders of Magnitude.. less.. sophisticated and powerful than even ''street' 2 stroke engines... cc vs cc despite the total lack of nitro in the gasoline fueled moto versions to add insult to injury. I had always assumed the reverse .. In complete error.
Pretty well a moot point given that only a few serious 2 stroke Bike engines currently exist especially so with the recent demise of Moto2 GP... $250K.. 250 cc race only engines tho.
Aluminum works just fine.
Try a G&Z .061 on for size with a 4.2x4 prop.
Try a Nelson 6.5 or Profi 6.5cc with a 7x7......then report back here with your findings.
08-01-2012, 06:31 PM
#19
RE: Norvel .074 on a tuned pipe
I think an FAI Speed plane gets about double therpm from the pipe. Granted, unpiped rpm is quite slow because the exhaust timing is so radically high. But still 40,000 rpm is revving. They have aluminum pipes with a very small tailpipe hole dia. now compared to when I did it.
08-01-2012, 11:07 PM
#20
RE: Norvel .074 on a tuned pipe
ORIGINAL: danilo-2
Material resonance is Critical ! Ali and Carbon fibre are erm Useless at that.
Ever seen any musical instruments of either material?
Material resonance is Critical ! Ali and Carbon fibre are erm Useless at that.
Ever seen any musical instruments of either material?
In many musical instrument the material itself vibrates (eg. a drum skin) and that in turn sends out pressure waves that we hear as sound.
So these are two completely different things.
08-06-2012, 04:04 PM
#21
RE: Norvel .074 on a tuned pipe
to Quote Aspeed
"Oh and just for the sake of argument, I have actually seen a picture of a carbon fiber guitar somewhere. "
I believe the name was Kaman just like the helicopter of the same name. The brand is Ovation Guitars. It is one of many currently made with composites including Carbon.
Jim H
"Oh and just for the sake of argument, I have actually seen a picture of a carbon fiber guitar somewhere. "
I believe the name was Kaman just like the helicopter of the same name. The brand is Ovation Guitars. It is one of many currently made with composites including Carbon.
Jim H
08-06-2012, 09:28 PM
#22
RE: Norvel .074 on a tuned pipe
I think this is a case of there being no such thing as a "One size fits all" rule about which materials work best...for anything.
It all depends on what scale you are working with.
A 250cc engine might very well need a steel pipe...?
It all depends on what scale you are working with.
A 250cc engine might very well need a steel pipe...?
08-07-2012, 05:14 AM
#23
RE: Norvel .074 on a tuned pipe
Well CP...... just to give danli his due, why don't we try mounting a 250cc moto2 on a 60" span GLH, have Andy make us a couple of pipes, see if Larry has props in stock for it, maybe a 17X36? Should be a lot easier to hand flip than my S&S motors. I'm open for suggestions on how to hand launch......
Oh, and as for "toy motors", I ride Harleys so 250cc is a "Toy motor."
Oh, and as for "toy motors", I ride Harleys so 250cc is a "Toy motor."
08-07-2012, 08:08 AM
#24
RE: Norvel .074 on a tuned pipe
What size engine are these..?
I read somewhere that pipe material / wall thickness has an effect on how the pipe operates.
The only materials practical for tiny model planes have to be the lightest ones that will do the job.
The .061 G&Z pipe is unbelievably thin and light. It actually threads together at the fattest portion.
I read somewhere that pipe material / wall thickness has an effect on how the pipe operates.
The only materials practical for tiny model planes have to be the lightest ones that will do the job.
The .061 G&Z pipe is unbelievably thin and light. It actually threads together at the fattest portion.
08-07-2012, 08:11 AM
#25
Senior Member
RE: Norvel .074 on a tuned pipe
I don't know that I would be too proud in calling a Harley motor more manly than a 250.... That 250 probably made just as much or near the same hp..... maybe 20hp more if it were a later water cooled model as TZ250's and RS250s were making 80-90hp.
A real bike makes better than 160hp and is faster than your Harley in first gear.[>:] God, I love me some superbikes... my current fast bike is a GSXR1000 with a few goodies on it and traction control. It's making 177 at the wheel and doesn't wake the dead going from bar to bar.
Oh, and just to keep this model related, if you could scale a Cyclon .061 to 1000cc's, it would make 7,000 hp.
A real bike makes better than 160hp and is faster than your Harley in first gear.[>:] God, I love me some superbikes... my current fast bike is a GSXR1000 with a few goodies on it and traction control. It's making 177 at the wheel and doesn't wake the dead going from bar to bar.
Oh, and just to keep this model related, if you could scale a Cyclon .061 to 1000cc's, it would make 7,000 hp.