OS .25

Tell us what you do to get the best performance from your engines.

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Steve108
Posts: 9
Joined: Wed Apr 13, 2005 5:42 pm

OS .25

Post by Steve108 »

Hi everyone,
I have seen a lot of info on increasing the power of an OS .25FX by switching carbs and removing head shims. I would like to know if these apply to the LA engines too. Or, would I be better off with an FX? Is an LA fine if it's used for very occasional combat?

Could someone outline how you all set up your engines before flight?

Thanks,

Steve
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Dane McGee
Posts: 885
Joined: Fri Feb 21, 2003 1:57 pm
Location: Greenville, Texas

Post by Dane McGee »

Hi steve, welcome to the site. [:D]

The 25 fx is hard to beat for box stock power and reliability. I don't have any mods on my fx's other than removing the muffler baffle which works fine since I use a fuel bladder instead of an standard clunk tank. I would advise no mods and normal break-in and run it box stock and I feel you will be very very pleased with the power.

If you feel you must have some type of carb changes or whatever there are experts here that can help you out......dunno about the mods on a LA.................. I have a couple, they are great, but just don't have the power of the fx.
PROPPY JON
Posts: 535
Joined: Sat Aug 31, 2002 7:29 pm
Location: USA

Post by PROPPY JON »

dude, the fx is the way to go it will always start, make good power and just take it out of the box and bolt on plane and run it the la s are a bushing engine and after awile the bushings start leaking and loosing power so once again buy the fx way more for the buck and will last u longer run a 9x4 mas and away you go
sgilkey
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Joined: Mon Mar 19, 2001 8:26 am

Post by sgilkey »

If you already have an LA you might as well fly it, but if you are planning a purchase trust us you will be MUCH happier with the FX in the long run, it is about as user-friendly as you can get, plus smooth, powerful, and reliable. For the LA, even with a mousse can pipt, no matter how much you tweak it you're not going to be as powerful as a stock FX, and with the FX you can add a MCP and have a fully competitive combat motor that will take you as high as you want to go in competition.

If you want to use your LA, try:

remove muffler baffle
ream out tailpipe to 1/4 inch. note: this will affect fuel draw in tight turns, be sure to mount your engine as low as possible relative to the tank, tip it 45 degrees down on the muffler side, etc.
remove head shim
install a 40LA carb (simple and very effective power increase. can also use the Tower 40 carb, 40FP, etc, but the 40LA has the largest bore and is set up for the remote needle)
try a mousse can pipe

note that the LA is nice and light which is it's best feature. however, it has a different mounting pattern and exhaust bolt spacing, so if you ever upgrade to an FX, you'll need a new engine mount pattern, and if you have a MCP for the LA it won't fit the FX. Thus if you plan to stay with combat it makes sense to consider starting with the FX. Good luck
Steve108
Posts: 9
Joined: Wed Apr 13, 2005 5:42 pm

Post by Steve108 »

Thanks, I think I'll go with the FX. Off topic but do you know of any combat in southern NH?

Thanks again,

Steve
Bad Dawg
Posts: 388
Joined: Fri Jul 18, 2003 3:27 pm
Location: Solomon Islands

Post by Bad Dawg »

Theree are a few guys at the Southern New Hampsire Flying Eagles in Merrimack that fly Gremlin Combat here is a link to their combat info http://www.snhflyingeagles.org/rccombat.htm
and the southern New Hampshire RC Club had some contests the last time I was up there
http://www.snhrcc.org/

By the way, the Flying Eagles are some of the nicest folks I've ever had the pleasure to know, it's a real friendly field, but a tough place to fly combat.
Steve108
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Joined: Wed Apr 13, 2005 5:42 pm

Post by Steve108 »

Do I break in the engine before modifying or after?

Thanks,
Steve
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lightning
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Location: USA

Post by lightning »

Yes Steve, get at least 3 or 4 tanks through the motor before you start to tweak it.
Steve108
Posts: 9
Joined: Wed Apr 13, 2005 5:42 pm

Post by Steve108 »

Okay thanks.
Steve108
Posts: 9
Joined: Wed Apr 13, 2005 5:42 pm

Post by Steve108 »

So heres the plan: I'll break it in like you guys reccomend - running for 2 minutes then letting it sit overnight...
Then I am going to remove the head shim and muffler baffle. I have a spare 40 la carb, is it beneficial to install this? I am also going to widen the crankshaft port a bit as described on this forum.

Am I missing anything?

Thanks
Alex Treneff
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Post by Alex Treneff »

On any combat engine I would use socket-head muffler bolts, becuase you will likely be moving the engine to another airframe at some point, and eventually the phillips screws (J.I.S., actually) will strip if you're not careful. However this is just personal preference, and will not affect the power of the engine if you are careful get the stock screws tight. It's just a matter of convenience.
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