Speed prop for Norvel .25  
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Speed prop for Norvel .25 - 11/18/2007 11:17:47 PM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline 		Hey all,

I built a small .25 pylon type plane and have a norvel .25 on it. I was hoping to get some input on what would be a good prop size for speed for this engine. The engine appears to have some power to it , just dont have any experience with these smaller prop sizes.

Thanks

Z
       Post #: 1

RE: Speed prop for Norvel .25 - 11/18/2007 11:50:23 PM   
combatpigg



Posts: 9782
Joined: 11/22/2003
From: arlington, WA, USA
Status: offline 		I've seen some impressive speed from Norvel .25s on RC combat planes. I think an 8x6 would be a good place to start.
Shaving the blades will boost performance.

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RE: Speed prop for Norvel .25 - 11/19/2007 1:49:31 AM   
vicman



Posts: 6182
Joined: 12/8/2002
From: Valdese, NC, USA
Status: offline 		I agree with CP. Start at 8X6 and mess around from there. I have gone as high as 8X8 with my MVVS .28 only to go back to 8X6. APC of course.


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RE: Speed prop for Norvel .25 - 11/19/2007 3:08:43 AM   
combatpigg



Posts: 9782
Joined: 11/22/2003
From: arlington, WA, USA
Status: offline 		The .25s I've run have a narrow range of props that work. 8x6 is actually kind of big, 7.5x6 with thin blades will make a huge difference. MAS props can be reworked to get good gains. It is amazing what a quantum leap in power the .32 has over the .25s.

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RE: Speed prop for Norvel .25 - 11/19/2007 6:32:02 AM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline 		Thanks guys. Sorry if stupid question but new to this speed thing. But what is "shaving" the blades involve?

Thanks
Z

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RE: Speed prop for Norvel .25 - 11/19/2007 9:20:24 PM   
rmenke


 

Posts: 1772
Joined: 6/25/2004
From: Merced, Ca., CA, USA
Status: offline 		Zman:

Listen up to combat pig's comments as to prop size, and do yourself a real favor and start out with a good engine, at least the OS 32, or best Jett 35. Shaving down props to engine max. is a art form you should leave until you have a old fox mentor. You can get almost to the same place by taking a little off the tips and reballance until you reach max. rpm. Yes, there is a point of no return value, but the engine should tell you that. Each one is different every day. Perfection today may be poor tomarrow. Why do you think the old salts have 50 or so worked props in their bag along with the radio tuned to the weather channel, and big notebook? ENJOY

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RE: Speed prop for Norvel .25 - 11/19/2007 10:19:38 PM   
vertical grimmace


 

Posts: 1143
Joined: 3/13/2004
From: ft collins , CO, USA
Status: offline 		Also, if you can add a 1\4 wave exhaust like a Jettsteam muffler or a Combat mousse can will really help. Not sure on the Norvell and how it would mount but I am sure there are some combat guys with experience with this engine that can chime in.

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RE: Speed prop for Norvel .25 - 11/19/2007 11:02:03 PM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline
quote:

ORIGINAL: rmenke

Zman:

Listen up to combat pig's comments as to prop size, and do yourself a real favor and start out with a good engine, at least the OS 32, or best Jett 35. Shaving down props to engine max. is a art form you should leave until you have a old fox mentor. You can get almost to the same place by taking a little off the tips and reballance until you reach max. rpm. Yes, there is a point of no return value, but the engine should tell you that. Each one is different every day. Perfection today may be poor tomarrow. Why do you think the old salts have 50 or so worked props in their bag along with the radio tuned to the weather channel, and big notebook? ENJOY



Nothing wrong with the engine, it is actually very reliable and has some bite for its price range!. I am not into racing, I just slapped together a little pylon plane to have fun with and wondered what would be a good prop size to get the most out of this engine. I am mainly into 3d flying, from small stuff to GS, I just put this together for a little change of pace .

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RE: Speed prop for Norvel .25 - 11/20/2007 2:13:09 AM   
combatpigg



Posts: 9782
Joined: 11/22/2003
From: arlington, WA, USA
Status: offline 		Zman, shaving the blades is done with a sharp knife blade about 90 degrees to the work surface. The idea is to thin the airfoil, remove mass from the blades. Limit the work to the outer half of each blade, a slight radius on the LE and razor sharp TE. After the rough shaving, then finish up with a sanding block. I don't bother to refinish wood props but a little oil works OK. The prop mfg wants to sell a safe prop more than he wants to sell a fast prop, so the blades are made thicker than what is best for performance.. Shaving the blades can really make a little engine come alive. Clipping the tips is also a prop tuning method. Figure that the smaller the engine, the less likely you will ever find the perfect off the shelf prop. You should have a good prop balancer and be willing to put in the time. The more practice you have, the faster it goes.

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RE: Speed prop for Norvel .25 - 11/20/2007 10:33:47 AM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline 		Thanks a bunch for the explanation. This is something I probably could do but as mentioned might be more work than wanted for what I am trying to do, just get this little plane going fast . I can probably achieve that and stay with stock blade size. The plane is actually more a .15 size than .25 so it is scooting along pretty well. Here is a pic.

Z

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RE: Speed prop for Norvel .25 - 11/20/2007 2:44:39 PM   
vicman



Posts: 6182
Joined: 12/8/2002
From: Valdese, NC, USA
Status: offline 		Looks more like a combat than pylon plane to me. Slap an 8X6 on there and burn some fuel.


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RE: Speed prop for Norvel .25 - 11/20/2007 3:23:24 PM   
Zman39



Posts: 467
Joined: 1/27/2005
From: Central, FL, USA
Status: offline
quote:

ORIGINAL: vicman

Looks more like a combat than pylon plane to me. Slap an 8X6 on there and burn some fuel.



Man, I guess I came into the wrong forum to ask questions. Sorry to the reference to a pylon plane, I was just trying to get a question answered. As mentioned, I dont have much experience in this field of RC, I am just trying to have fun with a little homebuilt plane and engine already owned. Hope everyone has a nice thanksgiving.


Z

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RE: Speed prop for Norvel .25 - 11/20/2007 4:03:29 PM   
vicman



Posts: 6182
Joined: 12/8/2002
From: Valdese, NC, USA
Status: offline 		I didn't mean to hurt your feelings.
In the air is in the air. Shoot it could have been electric and I would think the same thing.

No slight intended. Sorry if it came out that way.


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RE: Speed prop for Norvel .25 - 11/20/2007 4:24:39 PM   
vertical grimmace


 

Posts: 1143
Joined: 3/13/2004
From: ft collins , CO, USA
Status: offline 		It looks a lot like a kit I used to produce called the "Disobedient". It was based on a small Q-500 pylon design but was marketed as a combat plane. That was back when open B was brand new. The designs have evolved naturally, but that should be a great flying plane. The best thing is to take several differant props with you and see which one you like best.

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