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Engine basics => Engine set up tips => Topic started by: Craig Beswick on March 15, 2020, 02:25:17 AM
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Hello all,
can anyone tell me anything about an OS 32SX converted to stunt? Pros and cons?
Thank you
Craig
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I think I have one in my collection, but I have more experience with the .32F. When I got the SX, and gave it a good look over and checked out OS parts lists to see what parts fit both engines and such. I'm taking a guess that it is the same as the F series engine in a different case, and is based on the .32 helicopter engine. A venturi in the .240 to .250 range using stock needle valve, and starting with an 11-4 prop is a good start. Size and weight of the airplane will make some differences. I like mine and pick up any OS.32 that I run across if it's a good deal. I have a Randy Smith OS.32 in my kinda heavy SIG Primary Force that weighs in about 45 ounces or more, and have never had a bad run with it. I can see no changes in the cylinder liner compared to my other known stock engines. I just haven't had time to mount up the SX and see how it does.
Type at you later,
Dan McEntee
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Maybe a bit high on the blow down , for 4-2-4 . rady might angle / raise trans . Or do a lou Woolard . ( drop liner- raise transfer . ANYWAY , seems to be THIS ;
http://sceptreflight.com/Model%20Engine%20Tests/OS%20MAX%2032%20SX-H.html
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Hey Matt,
Thank you for the response. Not that I understood any of it😀. But, it is not the Heli version.
I should have said I am not competent to make internal changes. Adding a Venturi and NVA is the extent of my abilities!
Thank you Dan. Worth it for the right price.
Craig
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Two or three of the fellows, that I know including myself have flown with these engines for a few years, and have been really pleased with them, about the only thing that we have done is reduce the squish band to about half the size, and of course set it up for control line.
I usually break mine in using a 9x4 prop and 10-22 fuel they are very strong/powerful for there size and work well in Nobler sized models up to Cardinal size models, when I am able to fly I usually use a 10x4 prop.
Hope that this helps and do not stop asking questions as the guy's that are here on Stunt Hanger are VERY helpful..
One more thing, when you are thru flying for the day, run all of the fuel out of the engine and use after run oil to save the bearings.. The after run oil that I use is Marvel Air Tool Oil.. Good luck...
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Thank you for that. I am just in the process of justifying the spend to myself. Ah budgets.....
I try to search as much as I can before I ask any questions, but some answers aren't obvious in the search engine. So thank you.
I appreciate the information about your set up. Any idea on Venturi size, .24 to .25 as Dan said and NVA?
Much appreciated
Craig
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Control Line 7 Helicopter are likely the same internally . Or is that R/C & Heli . LL~
Where the test says ' timing Periods ' the 152 & 120 give 32 deg. / 2 = 16 degrees ' Blowdown ' whereas Aldrich et al say 30 max ,
to drop back to a 4 stroke in the 4-2 rich / lean run set up .
But if youre not running 4 stroke it dosnt mater. anyway .
AND it might be irrelevant / obsolette or avoidable .
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I'll have to take mine apart and see what size it is. I think it has an OS style NVA. It is a through the body venturi, and attaches to the engine with the same size screws that hold the R/C carb on. Drop Jim Lee a line and see if he has then all ready to go and has the spare mounting screws. I think I have gotten a couple from him over the years.
The .32 was originally a heli engine, and for airplane use, they just changed to a round head. The SX has a heli counter part also I believe. i have one with the big heat sink head, and need to find an airplane head for it, or just start trimming and hacking at the heli head one of these days.
Type at you later,
Dan McEntee
PS to add, that a Helicopter engine needs to make it's power in the middle to 3/4 throttle range for proper control, and that is why they make good stunt engines with out too much fiddling. Most R/C airplane engines are designed to run at full tilt boogy throttle settings, but you can't fly a chopper that way all the time.
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Two or three of the fellows, that I know including myself have flown with these engines for a few years, and have been really pleased with them, about the only thing that we have done is reduce the squish band to about half the size, and of course set it up for control line .
That means something like this , leaving the bit thatll hit if it gets to close , fairly close ( like 10 thou. ) so it works right .
https://stunthanger.com/smf/index.php?action=dlattach;topic=42882.0;attach=249800;image
abducted from : https://stunthanger.com/smf/open-forum/flight-report-spring-practice-at-the-zambelli-aerodrome-taming-a-runaway-fp-40
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Thank you for that. I am just in the process of justifying the spend to myself. Ah budgets.....
I try to search as much as I can before I ask any questions, but some answers aren't obvious in the search engine. So thank you.
I appreciate the information about your set up. Any idea on Venturi size, .24 to .25 as Dan said and NVA?
Much appreciated
Craig
Hi Craig
The SX will work, use a 265 venturi with a standard .157 diameter spray bar. The AX is the best and strongest ones of the buch, and works very well, I have sold many of them Use a 111 x 4 wood, or try a 11 x 4.5 Cyclone, people have really good results and they are great on Nobler Chipmonk size planes
Randy
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Thank you to all. I have just put an offer on it.
Thank you Randy. I flew with that LA46 of yours I have that I had the issue with. It tan beautifully, from start to finish. Soft break at about 10 o'clock, fantastic.
Craig
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Just an update for anyone interested.
I bought the 32SX and after a 6 week delivery put in a Jim Lee .265 Venturi and NVA.
I ran it yesterday. Started easy enough but it didn't want to needle or pick up to a 2 stroke run at all. I have a new test bench and was using the tank that it will fly with. Well, it seems engines do not like it when tanks are upside down!!!! No sooner had I turned it right side up, half a flick and boom away she went. a relief really.
It is going into my Nobler ARF I half destroyed so will hopefully be a good fit. I have had to glass the wing and completely recover with tissue so will be a lot heavier than original.
Craig