Reliable inverted engine idle? How?

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Reliable inverted engine idle? How?

Postby fmellott » Fri Feb 02, 2007 7:01 am

Hello, considering a set of plans that require inverted engine mounting of a 2c engine, .40 size. At my local flying field, I see guys having nothing but problems with inverted mounting. Yet in publications, I see them pretty frequently, and therefore assume that it can be done successfully. What are the key steps involved with ensuring that an inverted engine will idle properly? I've seen suggestions from tank mounting height to need for uniflow style tank. Thanks. Frank
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Postby Frank Klenk » Fri Feb 02, 2007 6:27 pm

I run inverted setups and they work well. I'm not sure if you are running a r/c carb, you did not say. The most important part is your tank height. You want the tank centre to be level with the carb inlet. You may have to play with this a bit. Perhaps tank bottom level with inlet but certainly not higher.
What is your setup?
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Postby maskedplum » Tue Jun 05, 2007 2:00 am

Well, whatever you do, you will not get better reliability from the engine than running it upright, if you expect any type of idle...
You might have to change the design of the model, so you have to decide what your priorities are...

Robert.
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inverted engine

Postby fnhaddo » Tue Oct 02, 2007 12:04 pm

I have run engines both 4 cycle and two inverted for years and have never had a problem. I have an OS120Surpass in a SIG 1/4 scale Cub thats inverted and it runs and idles as well inverted as upright.. Some guys run an onboard ignition that works well. Some use some type of pump.I never have needed one. I used a Perry micro Oscillating pump in a Goldberg Anniversary Cub with an inverted Saito 45 and it idled perfectly.

Think about this?? If an engine won't run inverted how do we fly upside down for any length of time. It just takes a bit of know how and the effort to get it right.
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Morre comments on inverted engines.

Postby maskedplum » Tue Oct 02, 2007 1:45 pm

maskedplum wrote:Well, whatever you do, you will not get better reliability from the engine than running it upright, if you expect any type of idle...
You might have to change the design of the model, so you have to decide what your priorities are...
We are not only talking about "running" the engine inverted here,
we are talking about starting it, (which probably involves putting on the glow driver, and taking it off after a start), adjusting it, (once running), changing the plug, putting in after-run oil, and visually checking on things on a regular basis; and idle reliability, (which is MUCH greater upright)!! NONE of the "normal operations" of a model engine is easier, or better, than with upright format. I have run engines for decades, both glow, and gas, and for sure, if you have a choice, GO WITH THE UPRIGHT FORMAT !!!
Life will be much easier !!!!!
"Most" engines flood much easier inverted. Raw, and excessive, fuel puts out the glow plug, or the spark plug. If you flood out, you have a much larger problem to
deal with... You must either invert the plane (hay, look, you now have an upright engine!!!), or go through the routine of taking out the plug, blowing it off, changing it, or shaking out the oil / fuel, and checking if the fire will work now. If not? Do the clean out step all over again, and maybe a third, or forth time...(if you did not properly clean out a flooded engine)...
Oh, you can invert the plane and start it up that way.....but....
if you do this alone, you will really have a DANGEROUS handfull !!! And SAFETY alwlays trumps..... Even with help, turning over the plane to start the engine requires a return to "normall" attitude to fly. This turnover is tricky with a running engine, and often oily plane...
The ONLY thing I give to an inverted engine format it:,,,,, well, it looks better..... THAT is NOT enough to make this format a "CHOICE"...
Go ahead and beat up on me how you "never" have problems with an inverted format. I have been there. Upright is BEST !!!

Robert.
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