OS 25 FX how to get more power
06-15-2007, 01:30 PM
#26
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RE: OS 25 FX how to get more power
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).
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).
06-15-2007, 01:43 PM
#27
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RE: OS 25 FX how to get more power
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?
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. [X(] I came here for information because I know that the combat boys know how to milk power out of an engine! [8D]
Thanks to all for the help and information!
06-15-2007, 04:25 PM
#28
RE: OS 25 FX how to get more power
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.
BTW, my OS .25 FX is turning right at 20,000 with a MAS 9-4 prop on a can. No mods.
06-15-2007, 07:10 PM
#30
RE: OS 25 FX how to get more power
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.
06-16-2007, 03:13 AM
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RE: OS 25 FX how to get more power
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.
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.
06-17-2007, 05:28 PM
#33
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RE: OS 25 FX how to get more power
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.
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.
08-13-2007, 11:19 PM
#35
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RE: OS 25 FX how to get more power
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
Also SOME DO IT YOURSELF INFO HERE:
http://www.uoguelph.ca/~antoon/hobby/mcm.htm
09-20-2007, 01:13 AM
#36
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RE: OS 25 FX how to get more power
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
-Matt
09-20-2007, 02:27 PM
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RE: OS 25 FX how to get more power
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.
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.
D
