stunthanger.com
Engine basics => Engine set up tips => Topic started by: scott matthews on April 09, 2011, 08:35:53 PM
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Flew new motor today and seemed to lack some power, so what is the deal with the cone shaped piece inside the muffler by the pressure fitting?Is this part necessary to performance or does it just add weight and restrict the noise?
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Flew new motor today and seemed to lack some power, so what is the deal with the cone shaped piece inside the muffler by the pressure fitting?Is this part necessary to performance or does it just add weight and restrict the noise?
It definitely changes the way it runs, and in my experience, it runs much better with the muffler intact. But you can take it out and see.
I am surprised you don't have enough power - what prop are you running?
Brett
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I'm assuming you're talking about the Galaxy. The LA .25 *should* be plenty of power. How much the the plane weigh ready to fly? Leave the cone in the muffler. If you take it out, power does not really increase but fuel usage does (I don't know why) and the run gets erratic.
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Thanks for the replies I will leave it in.I have notice that I am breaking in a 20 year old new Max 40 and it now has about 10 to 15 runs on it and its starting to run more consistent and leaner on fuel, plus easier to start.How many runs do you think it takes to get the Max 25 to start to settle in.The reason I asked this question is the Max 40 does not have anything inside the muffler but it is 23 years old and its just now starting to fly.
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The LA 25 breaks in very quickly. Usually just a few minuets run time will do it. After 3-4 tanks of gas it should settle in to some sweet runs.
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Does leaving the baffle in the muffler for a better run apply to all OS LA engines? Specifically the .40 and .46?
Joe
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I think it would be the same, Joe. However, I've never run a .40/.46LA with the OS muffler...but my Magnum XLS .36 thinks it's just dandy! The one thing I'd consider is opening up the exit spout...but I haven't done that, either. I figured that a .46 muffler on a .36 should flow enough already.
Scott, that .25LA will run fine after a half dozen tanks...but put the 9-4 APC on it until it's got a couple dozen runs. The 9-6 is too much load, and you're overheating it. Set it richer, let it buzz up some, and it'll be better. After it's
stabilized the needle setting (doesn't need to be leaned out every run or two) and fuel consumption, then get the 10-4 APC on it. I still think the plastic backplates are a potential problem, and would like to see you replace it with an aluminum one from a .25FP or CNC unit from Curtis Shipp. If it starts but quits for no apparent reason...that's the reason... H^^ Steve
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Who is this Curtis Shipp you speak of and does he have a web site to buy this part?
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I've used the OS 15, 25, and 40-size mufflers. They do a great job of making the engine quiet without loss of power. I do not believe that opening the exhaust orifice would increase power because it's not the ultimate limitation of power on these engines.
People change to tongue mufflers purely for mass reduction.
If the plane come out nose heavy and you need tail weight, that's double trouble. So you spend $25 and save 2-3 ounces.
On the other hand, if you need nose weight you have a free fix.
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Info on Curtis...
AMA 753063 / Advanced Stunt Flyer Finally
LA 46 / 40 / 25 / 15 CNC backplates
« on: February 01, 2010, 10:35:17 AM » Quote
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I am stocked up on backplates again. If you have been waiting on them send money and I will send backplates.
$12.00 each + $3.00 shipping. Thanks from Curtis Shipp.
PS: Gil Causey your super secret, hi perf, cheating, stuffer, outlaw, backplates are ready also. But I will keep it quite.
My address is
Curtis Shipp
Po Bx 1255
Gardendale, Al 35071
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HI Scott,
The OS .25LA works best with the 9-4 or 10-4 APC it seems, as Steve said. And it should be in a "wet 2" cycle. Very, very consistent and and puts out more than enough power for its size.
Go up to the "members tab" and search for Curtis, his email addy is there in his profile. I would post it but there are web crawlers (or some such) that just search for email addresses in posts on the internet to spam through. I went to the page that the "D"'s start on. He is there near the end of the "C"'s as Curtis Shipp. He was logged on around 10:30pm on the 14th so he is around. Outstanding back plates and very very easy to work with. Highly recommended.
Big Bear