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RE: OS 25 FX how to get more power - 6/15/2007 7:30:52 PM   
Montague



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Joined: 4/19/2002
From: Laurel, MD,
Status: offline 		Since he's talking about .25's I'm guessing he is using them in something like OpenB class combat which would not allow .32 size engines, but does allow modified .25 size engines. So while spending the money on a .32 would be cheaper than buying carbs for .25's, it would be allowed in the contest.

Personally, I don't mod my OS .25FX engines other than to put on a mousse can.

(edit, changed "now" to "not". sorta changed the whole meaning I was going for).

< Message edited by Montague -- 6/17/2007 11:23:31 PM >


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RE: OS 25 FX how to get more power - 6/15/2007 7:43:47 PM   
Razorback58



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From: Texarkana, AR, USA
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quote:

ORIGINAL: vertical grimmace

The .32 sx carb is a direct drop in, swap. The thoat of the venturi is larger. This will give you more power but remember you are reducing the engines ability to draw fuel. It may go lean in tight manuevers and muffler pressure will be mandatory. I have not flown one set up this way but I have run one once.
To purchase this carb plus the cost of your .25 you may be better off with the .32 in the first place. I wonder what your objective is? What plane are you going to put this powerhouse on?




I already have the .25, and will just keep an eye out for a .32 carb. It's just a case of tinkering and trying to get the most out of what I have. I'll be running a header and mousse can muffler, so muffler pressure will not be a problem. As far as what I'm putting it on, it will go on a profile plane. I came here for information because I know that the combat boys know how to milk power out of an engine!


Thanks to all for the help and information!

< Message edited by Razorback58 -- 6/15/2007 7:45:08 PM >

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RE: OS 25 FX how to get more power - 6/15/2007 10:25:07 PM   
vertical grimmace


 

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From: ft collins , CO, USA
Status: offline 		Well, Since your tinkering, Other mods would be- Opening the up the intake port of the crankshaft. If you do this to increase the duration of the port it has more time to intake fuel and air. Another thing is to enlage the hole in the crankshaft itself. If you can get a look at a Nelson engine these are a couple of the items that help them to go fast. The problem is the crank can only be opened so much before it becomes weak. If you are cruising for information, try to pick the brains of some CL speed guys. They know how to get the most out of an engine and might be able to talk you through some mods. Again you need to know what your doing to perform these, so if not familiar seek assistance.
BTW, my OS .25 FX is turning right at 20,000 with a MAS 9-4 prop on a can. No mods.

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RE: OS 25 FX how to get more power - 6/15/2007 10:27:22 PM   
Razorback58



Posts: 795
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From: Texarkana, AR, USA
Status: offline 		20,000 RPM's with just the can? What fuel are you using?

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RE: OS 25 FX how to get more power - 6/16/2007 1:10:03 AM   
vertical grimmace


 

Posts: 1145
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From: ft collins , CO, USA
Status: offline 		I am using 15% powermaster. I have a little differant can though. My typical "kentucky" style are down in the 19,000 range. The one I really like is a little larger in diameter. I also just have a hole for exhaust up near the front of the can. I think this essentially lengthens the can. I need to find a cheap source though as I am losing them to mid-airs.

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RE: OS 25 FX how to get more power - 6/16/2007 9:13:27 AM   
The Internet Killer


 

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From: Ferndale, WA, USA
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quote:

ORIGINAL: vertical grimmace

I am using 15% powermaster. I have a little differant can though. My typical "kentucky" style are down in the 19,000 range. The one I really like is a little larger in diameter. I also just have a hole for exhaust up near the front of the can. I think this essentially lengthens the can. I need to find a cheap source though as I am losing them to mid-airs.


Do you have any pictures and build info on your mousse cans ???

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RE: OS 25 FX how to get more power - 6/16/2007 1:07:56 PM   
vertical grimmace


 

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From: ft collins , CO, USA
Status: offline 		I will try to post some pictures. They are extremely easy to make.

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RE: OS 25 FX how to get more power - 6/17/2007 11:28:45 PM   
Montague



Posts: 4632
Joined: 4/19/2002
From: Laurel, MD,
Status: offline 		Btw, since you're using it in a profile, you might actually want to re-consider using a pipe or mousse can, or messing with the intake port of the engine.

The reason is that tuned pipes tend to make the engine "peaky" and make the throttle response really non-linear. As you throttle up, the engine will suddenly come "on the pipe" as it hits the resonance, and the rpm will make a sudden jump up. If you're trying to hover, this may not be what you are looking for. Just something to consider.


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RE: OS 25 FX how to get more power - 8/14/2007 1:48:04 AM   
pmoen70


 

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Joined: 10/5/2004
From: Davenport, IA, USA
Status: offline 		http://www.spadtothebone.com/SPAD/Mufflers/

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RE: OS 25 FX how to get more power - 8/14/2007 5:19:28 AM   
gullwingcorsair



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From: New Gretna, NJ, USA
Status: offline 		GO HERE http://www.flyingzhobbies.com/main.html CLICK Specials Products

Also SOME DO IT YOURSELF INFO HERE:
http://www.uoguelph.ca/~antoon/hobby/mcm.htm

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RE: OS 25 FX how to get more power - 9/20/2007 7:13:56 AM   
Flyboywbl


 

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From: Bozeman, MT, USA
Status: offline 		well i found out how to get 1000 more RPM with jst a slight modiflication to the muffler. first take the baffel out and then all you do is dremel off the muffler outlet pipe flush with the muffler body. Then you drill out the hole to 5/16 of an inch. Alot louder so i would not recomend this for a feild witha low DB rule. You gain about 20 more dB at 10 feet. If you don't want to bother messing with porting and timing of the engine this is a great little upgrade to get another 1000 rpm.
-Matt

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RE: OS 25 FX how to get more power - 9/20/2007 8:27:04 PM   
Demon



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From: Ledyard, CT, USA
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quote:

ORIGINAL: Flyboywbl
first take the baffel out and then all you do is dremel off the muffler outlet pipe flush with the muffler body. Then you drill out the hole to 5/16 of an inch.

Very true, Matt, but drilling the outlet to 5/16" also causes loss of pressure to the fuel tank (if you have it set up that way). Just removing the baffle is good for 800+ RPM, and doesn't ruin your fuel pressure.

D

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RE: OS 25 FX how to get more power - 9/21/2007 2:35:21 AM   
glowplugboy


 

Posts: 580
Joined: 12/26/2001
From: Pasadena, TX 77505/77508, TX, USA
Status: offline 		OR, you can order up a JETT BSE .25 and simply bolt it to your airplane!

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RE: OS 25 FX how to get more power - 9/26/2007 3:55:17 AM   
Tkeith9512


 

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Joined: 4/11/2007
From: Norfolk, VA, USA
Status: offline 		LA and FX mousse can comparison

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