Propellers for Norvel engines
 

Question #1
What are the screw sizes / lenghts for NV .049, .061, .074?

Question #2
What are the recommended prop sizes (range) for each of the above engines?

Thanks
Bernie
www.coxengines.ca

RE: Propellers for Norvel engines
 

Iknow a guy named Aldon Kelly , he owns Merlin Glow Plugs. Can probably tell you ten times what you want to know about them . http://www.rcuniverse.com/forum/js/f...ey/msn/lol.gif

RE: Propellers for Norvel engines
 

Thanks and, yes, I deal with All thethe time. Forgot that he was quite knowledgeable about Norvel.

Seems the screws are M3 / M4

RE: Propellers for Norvel engines
 

.049, .061 - M3 x 20

.074 - M4 x 25

All are partially threaded. If you use a fully threaded prop screw, the spinners will fit loosely. I usually buy partially threaded allen head screws in 25 mm and 30 mm lengths and then cut to length. The partially threaded shank is a better match for the id of the spinner.

5x3 to 6x3; 6x3 max for the .049 and .061 Big Mig; the AME needs to spin up more, so probably a 5.5x3 or less. A lot of folks have had good performance with the 7x3 on the .074

andrew

RE: Propellers for Norvel engines
 

The big problem with Norvel engines is the lack of props available to get them into the RPM range where they make good power. Props designed for 1/2A use are based on 60 year old engines with peak torque in the 17-20krpm range. A Big Mig can be loaded down with a 6-3 and happily run in the 18-19k range, but they make best power towards 21k. Same for AME's, the props available are either too big or too thick. APC's 4.2-4 is a good start but the blades ain't the best.

If I could wave a magic wand, I'd ask for 4-1/2-4's, 4-4's etc.

RE: Propellers for Norvel engines
 

If I had to choose one prop and never use any other, it would be an APC 5x3 for the .061

Stefan

RE: Propellers for Norvel engines
 

As for Props, I STILL like the 5x3 dubber ducky , the normal tip ones. I need to buy more. The cox 5x3 plastic are nice but snap easily.

But I fly control line, When we train kids, we like the old soft Topflight 6x3, it is so flexy that it won't break and and is more like a 6x2.

On my 0.74, I am liking the russian F2d props. Not cheap, but let the engine turn up. About a 6.5 x 3.5 but a thin blade that is a low load.





Prop screw is a M3 socket head which is 3.5mm I think. Our hardware stores have neet little cup washers that work better than the spinners with my starter.

RE: Propellers for Norvel engines
 

I recently was getting some numbers on a fresh .049 Big Mig and found that once you go past about 5.5 inch diameter you really get the engine out of its powerband. I was getting 22k on a 5x3, about 18.5k on a 5.7x3 trimmed about .060 on each end , But found the engine could barely swing a MA 6x3 at 14k!...Given this was a meatier MA prop ...But thats a lot of RPM drop! I'm anxious to run a .061 BM and see how they compare as far as where they want to hit the groove. Todd

RE: Propellers for Norvel engines
 

Big Mig .061 should do about 18000rpm on a 6x3 and 10% Nitro. For RC applications I think that 4 pitch is needed or one will only use full throttle. The MAS 5.5x4 is a nice one, so is the cox 5.5x4 (slightly higher load though)

What is the purpose of the original question?

RE: Propellers for Norvel engines
 

Before you make a final decision based on bench running, you might want to fine tune the performance based on actual use. Depending on the amount the particular prop will unload in the air, and the amount of drag presented by the airframe, actual performance may be different than on a bench. I would use bench figures as a starting point. Many have enjoyed the APC 6x2 and 5.7x3 for the .061 in the air. According to the old paperwork sent with early NORVEL engines, the .061 develops more power per ci as well as just more raw power than the .049, so don't expect to use the same prop on both the .049 and .061.

Of course these are just suggestions and opinions. The final choice, of course, is yours.

George

RE: Propellers for Norvel engines
 

Thanks to everyone for your information, advice and suggestions.

<span style="color: #0000ff">Wehave put a 4.5 x 4 propeller on the production schedule</span>. It will be made on an original Cox mould and we have requested they be made in the grey competition material Cox used. Just for the fun of itwe will also runsome in a material that is basically like the black Cox props (called"double-tough") but in a <span style="color: #0000ff">bright neon yellow</span>.

In 5" props we currently stock:
<ul>[*]5 x 3 Double tough[*]5 x 3 Grey <span style="color: #0000ff">competition</span> series[*]5 x 4 Double tough[*]5x3 Double tough(<span style="color: #0000ff">3-blade</span>)[*]5 x 3.5 Double tough - <span style="color: #0000ff">Left Hand</span> (<span style="color: #0000ff">3-blade</span>)[/list]In 6" props we currently stock:

<ul>[*]6 x 3 Double tough[*]6 x 3 Grey <span style="color: #0000ff">competition</span> series[*]6 x4 Grey <span style="color: #0000ff">competition</span> series[/list]All the above being Cox propellers.

Bernie

RE: Propellers for Norvel engines
 

Mr Cox,

The purpose of the OP was to establish what items we can supply to the Norvel community. In this case, propellers..

Although we do not plan production of any parts that fit Norvel besides the head conversions we already have (Alex from NV will serve you well for parts, I am sure) we wanted to see if there were any Cox items that may suit the Norvel community.

Seeing that Norvels are being sold again it made sense to explore this venue. Seems as if our props will work.

Bernie

RE: Propellers for Norvel engines
 

George Cleveland at GRS models has a nice selections of props for the .061 AME's on light clean pylon racers. Our reworked Norvels turn up 30,000 rpm + on these props.
http://pages.prodigy.net/gcleveland_...ls/index6.html

RE: Propellers for Norvel engines
 

The Norvel airplane engines .049 and .061 use M3-0.5mm x 20mm, the 0.74 uses M4-0.7mm x 25mm, and the .15 uses M5-0.8mm x 25mm.

The Norvel Cmax car engine .061 uses 5-40 x 3/4", like Cox .049 engines.

Luciano ///

RE: Propellers for Norvel engines
 

Ok, thanks Bernie, it is nice to see all the efforts from you. Cox props work well on the AP .061 too, it is only the limited supply that has made me stray into MAS and APC...

RE: Propellers for Norvel engines
 

MAS now has a 6.5 x 3.5...got one but have not tried it yet. Seems worth a try for .074s.

Jim

RE: Propellers for Norvel engines
 

APC has a 6.5x3.5 one too, but the APC 6.3x4 works very well on the Norvel .074.