Glow Engines Discuss RC glow engines

Four Stroke concern...

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Old 08-17-2013, 01:30 PM
  #26  
H5606
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I pulled the engine out and measured distance from lugs to bottom of crankcase vent nipple then I measured distance from mounting pads to nose sheeting support stringer - difference was 1/16". I confirmed with piece of modeling clay. I removed stringer material in this area to provide more clearance around the vent. I installed a new type F plug and just got back from flying today - made one flight with it set up as before. On the second flight, I opened the LS needle 1/2 turn and opened up the HS needle some as Hobbsy originally stated, started the engine and started adding travel volume at the high end. I was able to go from 10% up to 75% before it got ragged while tweaking the HS and then the LS needle. I was too lazy to pull out the tach, but there was a audible increase in power. I don't know if clearance to the crank vent did anything but thanks to all for the help so far...
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Old 08-17-2013, 03:59 PM
  #27  
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Except for the YS, the OS Type F is the best 4-stroke plug, in my opinion. They sell a ton of those, not because they are the cheapest, because they aren't, but because they run the best.

For a trainer, run a 12" prop. I like a 12-6 for that size engine. However, 4-strokes have no problem turning large props so a 12-7 or 12-8 will easily work. Your .54 should be a great engine for a trainer. With 10% fuel, an OS F plug and a 12-6/7/8 prop you have an excellent combination.

Do not ever expect your 4-stroke to ever sound like a 2-stroke engine. They just don't run that fast. Shoot for somewhere between 9.000 & 10,000 rpm. It is hard to tune by ear until you get a lot of experience. Also expect more smoke out of the exhaust than a 2-stroke.

One more thing, Thunder Tiger 4-strokes are ringed engines and have a reputation for needing a long time to break-in.
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Old 08-18-2013, 07:25 AM
  #28  
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Since I seem to be getting better results, should I go another half-turn open on the LS needle and try this whole process over again? I'm currently using 15% Cruel Pwr "4-stroke motion-lotion" with the APC 12X6 and I'll be surprised and ecstatic if I get 9,000 rpm. Up-lines looked a little better last flight yesterday than the recent past but not fantastic.

I had a World Engines on-board glow on the inverted engine in this airplane at one time but removed it after discovering a chaffing short to ground. If I can get the prescribed power out of the engine, Is it worth the complexity and weight of an additional battery pack and unit to put it back in to get a [possible?] lower idle?
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Old 08-18-2013, 08:03 AM
  #29  
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It is between the Fox Miracle, the GloDevil 4c special, the Taipan 4c and the Enya 3 to be the best all around plug.
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Old 08-19-2013, 05:47 AM
  #30  
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Hi dave i did'nt understand your post or read it carefully the first time.You say you ran a 13.5x6 on your 62 and are happy with the performance obviously.Do you still hafe the prop figures? i was'nt tuning mine well at the time it was my first saito engine..my God they can take an inexperience flogging fur sure
ps i always regret selling it before i got a chance to try and fix all the bad things i did to it
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Old 08-19-2013, 07:10 AM
  #31  
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Pete, I found the numbers, they are

Saito .62a
Plug===Saito SS
Fuel=== PowerMaster 15% nitro/18%/80/20 blend
Prop===Bolly 13.5x6
Peak rpm==9,330
Two clicks rich=9,150
Idle==1,800 rpm

Saito .62a
Prop Graupner 12x7
Fuel WildCat 15%/18%80-20 sun. castor blend.
Plug==Saito SS
RPM===10,100
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Last edited by Hobbsy; 08-19-2013 at 07:24 AM.
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Old 08-19-2013, 02:36 PM
  #32  
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Thanks very much i've copied them down.
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Old 09-22-2019, 02:50 PM
  #33  
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Long overdue but here's the rub now and just within the last three weeks:

Never flew this one much but decided that I put up with low performance long enuf - trying to fly an aerobatic routine at what equates to essentially half-throttle is lame... recently suspecting an air leak and planning to remove engine from airframe to analyze and perhaps put on a test stand, I finally took a look thru this thread yet again and decided to try leaving in place first. Perused a Magnum .52 4-cycle instruction sheet to help reinforce claims in this thread since the TT instruction sheet is for the air-bleed carb and reset hi-spd needle from 3 1/2 turns out - one turn in to 2 1/2 turns out with low spd needle reset from 2 1/2 turns out to 3 1/2 turns out with carb barrel wide open as instructed. Resisting any urge to fiddle with needles (except opening H.S. a couple clicks), turning the 12 x 6 APC, flew the airplane a couple of weeks ago on 10% Omega, #F plug, the airplane flew consistently the best I can ever remember with respectable up-lines and big loops/Cuban 8s... Put the 12 x 7 APC on expecting but seeing no higher straight line spd, verticals were about same; upon shutdown, the engine turned over rather stiff. Tach numbers with the 12 x 7 APC showed approx 8900 rpm; the tach on the 12 x 6 APC was displaying 9800 with low reliable idle and good response so my thoughts are to stick with the 12 x 6 and I am a happy camper now.

Thanks to all for the help here.


Last edited by H5606; 09-22-2019 at 03:27 PM. Reason: Wrong prop diameter/pitch; corrections
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