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Zenoah G62 with a 24 " prop???

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Old 05-06-2015, 01:50 AM
  #26
Pelle Gris
 
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The engine should run the same, powerwise, with both IE and magneto, at least my G-62 does. Also, starting the stock magneto engine is quite easy when you learn the right technique. But not all can or will, and in that case the EI conversion is a good idea. This also provides a nicer idle when using light props. With a larger heavier prop my own stock G-62 idles very nicely at around 900-1000 rpm.

What really makes a difference with regard to the G-62 is the exhaust. With the stock restrictive "silencer" the power is quite low, but slap on a good canister or a tuned pipe, and the power easily rises 30-50%.

My own G-62 does 6300 rpm with a Fiala 26x10, 100 rpm more than my GT-80 with stock exhausts, and a friends G-62 it will rip a Fiala 24x10 and 24x12 like crazy. The two 24" props run around 7000 and 6500 respectively. All on a KS1060 tuned pipe.

I donīt know if a 22x10 is the best prop for you, and if your Extra is heavy the G-62 simply might not be up to the task of supplying the power you want.
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Old 05-06-2015, 03:42 AM
  #27
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TInus - Thanks for your detailed response. This past weekend I was getting 6,800 - 7,000 with the Xoar 22x10, and the engine ran well, though my idle was high at around 2,000 RPM. Plane speed and vertical were good (I fly sport, not 3D (yet)). But I need to get that idle down - I'll start by richening the low end. Also I'm thinking of trying a 23x8 or 24x8 to lower the idle and see what affect it has on flying \ vertical. Your RPM numbers are very impressive (including the low idle!) , but it looks like a KS1060 tuned pipe costs $200, which is a bit much for me right now. But good to know I have that option, if I want to turn this engine \ plane into a monster!

Mike
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Old 05-06-2015, 02:26 PM
  #28
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With a light weight, or low diameter, prop, you may have problems getting the idle really low, especially with the stock mag ignition. But with EI you should be able to get a nice low reliable idle without too much difficulty.

My method of getting the low needle set just right involves setting the engine for low idle, and then leaning the needle until the rpm stops climbing. After this I check the response when accelerating, and if the engine hesitates the low needle is richened just enough to get a clean transition. After this initial setting I may have to adjust slightly after flying the engine but this is normally only a very slight adjustment.

A 24x8 prop should suit the engine fine I guess. Speed would be lower though.
My own engine does 7000 on a Menz 24x8 on a canister and 7100 on the tuned pipe.

Personally I almost exclusively use Fiala wood props. They load a lot less than most other props and you are therefore able to slap on a larger prop than usual. This in turn provides good thrust as well as making the idle lower due to the added centrifugal forces.
They are sold by http://www.vogelsang-aeroscale.com/fiala.html in the US it seems.
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Old 10-16-2016, 04:29 AM
  #29
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I picked up a 3rd scale Pup with a G62 and a Bennett muffler. My questions is when running a 24 inch prop on a 34# plane that has a lot of drag would the G62 do better on a 24x6 at higher rpms or a 24x10 to pull it better in level flight? My goal is to get good scale flight, nothing extreme and have a bigger prop for more ascetic scale appearance which I plan on using a xoar scimitar. Also considered a 26x6 scimitar but I'm thinking that would be over the top on a G62 and doing the whole belt drive gig is more money than I want to spend.

Russ
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Old 10-16-2016, 06:20 AM
  #30
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I have no experience with the Bennett exhaust, but itīs said that it offers very little resistance, so personally I would go for a 26x8 for your Pup.
As previously mentioned, I use almost exclusively Fiala wood props, as they load a lot less than other brands, and you are therefore able to use a larger prop than with other brands.
If using a higher loading prop, I would go for a 24x8.

With the stock exhaust on the G-62, the later model with the two outlet pipes, I got about 6100 rpm with a Fiala 26x8, and it powered my 1:3 scale Tripacer very nicely. Actually I rarely used more than 50% throttle, even for takeoff, since using full power had the 37 lb model leap off the ground in less than 30 ft.
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Old 10-16-2016, 12:43 PM
  #31
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Thank you Tinus, I plan to get the xoar scimitar for scale appearance which is close to something original that would be used for the sopwith pup. I have no idea how it loads up compared to say the regular gas version xoar or any other wood props, not a whole lot of information or blogs of anyone with experience on the scimitar type props. I think I will try the 26x8 first and if it seems to much than go with a 24x8 or 10 pitch. I was considering trying the 26x6 to have both a bigger prop and get higher rpm but not sure how much thrust I will loose going that low on the pitch and loosing rpms using a 26" prop. Again ideally a lot of guys wanting bigger props on these planes use the vogelsang geardrive or put a bigger 80-100cc engine in it but a G62 is what I got with the plane and what I have to work with! If someone wants to get rid of a gt80 for cheap I'm interested!
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Old 10-16-2016, 11:06 PM
  #32
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In my experience the G-62 tolerates large propellers better then the GT-80. The biggest prop I have been able to run comfortably on my own GT-80 is a Fiala 26x10, at just over 6K, and a cut down Fiala 28x8. The latter is cut down about an inch or so, but it rips like crazy. Rpms are about the same as the stock 26x10.

I have tried a Menz 26x8 on my own G-62 many years ago, and I believe the rpm was about 5300 or so. But even then the engine ran fine, and for a Pup, that do not need that much power, it should still be ok I guess.

I would get the 26x8, and if itīs too much for the engine you could cut down the tips until you reach a spot where the engine runs ok. My experience is, that even taking an inch of the diameter makes a real difference to the prop load.

You could read through this thread.
1/3 Scale Nieuport 11 in which there is some discussion about the G-62 and large propellers for WWI era birds.
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Old 10-21-2016, 04:20 PM
  #33
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A carb stack will eliminate most fuel spitting and make the needle more responsive when loaded below 6000
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Old 10-22-2016, 10:52 AM
  #34
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Quote:
Originally Posted by Kweasel View Post
A carb stack will eliminate most fuel spitting and make the needle more responsive when loaded below 6000
That does help with gas engines to have a carb stack mounted in the airstream at least in my experience but for my particular circumstance where the engine is completely incased in a cowl even after a carb stack is mounted it wouldn't benefit.
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