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Old Jul 08, 2012, 01:53 PM
flexwing addict
mark675's Avatar
midlands uk
Joined Sep 2004
2,676 Posts
Question
nitro engine question, upside down?

Hi guys,
might be a silly question but ive run engines right way up and lay down but im wondering if having one mounted upside down will cause any troubles?

only thing i can think of that might be a problem would be the fuel drowning the glowplug? have people ran them this way without problems?

engine is a o.s 25LA,

Thanks for any help you can give me
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Old Jul 08, 2012, 02:45 PM
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radfordc's Avatar
Lansing, KS, USA
Joined Jan 2002
1,435 Posts
Normally it's no problem. Occasionally an engine will have trouble idling well inverted. Also, if the oil drains down into the plug it can be hard to start the first time in a day.
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Old Jul 08, 2012, 03:29 PM
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mikmerl's Avatar
Athens, Greece
Joined Apr 2010
453 Posts
They run fine inverted.
Usually you will notice a slight drop in RPM once the battery clip is removed from the plug. (especially with a 4 stroke)
If you want to be absolutely sure that your idle will be low and reliable you can install a glow driver to power the plug at idle.
If you are starting with an electric starter make sure that the engine is not flooded by slowly turning the prop over by hand first to avoid a potential hydraulic lock.
One negative point about an inverted installation is that the engine is more vulnerable to damage in the event of a botched landing.

mike
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Old Jul 08, 2012, 04:26 PM
flexwing addict
mark675's Avatar
midlands uk
Joined Sep 2004
2,676 Posts
thanks for the answers guys thats a big help
it'll be on the back of my plane in a pusher configuration so shouldnt be able to hit the ground like it would on the front

ill give it a go and see how i get on

thanks again, mark
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Old Jul 17, 2012, 11:36 PM
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Canada, AB, Okotoks
Joined Apr 2007
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Great question, and a great answer. I also have been having issues with my OS 120 SP staying running at idle etc. I have been looking for a glow driver that i can hook into my reciever and power it that way. The only problem is I am trying to find a glow clip that is straight and not at a 90 deg angle. Any idea's?

John
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Old Jul 18, 2012, 10:00 AM
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mikmerl's Avatar
Athens, Greece
Joined Apr 2010
453 Posts
This may help if you need to go with a glow driver.

http://www3.towerhobbies.com/cgi-bin...&I=LXRYK2&P=ML

http://www.sullivanproducts.com/Prod...xMainFrame.htm

Before you do install a driver, experiment with the height of the fuel tank in respect to the carb/needle valve.
It can make a huge difference in some instances.
(or do both, that looks like a complicated piece of machinary with a ROOTS compressor)

mike
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Last edited by mikmerl; Jul 18, 2012 at 10:06 AM.
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Old Jul 18, 2012, 11:08 AM
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Canada, AB, Okotoks
Joined Apr 2007
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Thanks Mike, the tank height was the first thing i wondered about but the tank is right in the center of the carb and in the stock position in the airframe. Thanks for the info on the glow drivers, I'll look into them asap.
The motor runs amazing when it does, and with the blower on it's kind of scary when the engine gets to full power, but the way I see it is it's like hotrodding cars, the more performance you put into it the reliability goes down.

John
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