stunthanger.com
Engine basics => Four strokes only => Topic started by: Bob Reeves on August 06, 2009, 04:14:49 AM
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This shows just how much of a Saito 40's intake is choked off with a 10-32 nylon screw. This engine is turning a Thunder Tiger 11.3 X 6.5 prop at 8300 and flying a 47 ounce Shoestring profile with a 560 sq/in P-40 wing. It's flying 5.2 - 5.0 second laps on 61 foot eye to eye 15's and burning right at 3 1/4 ounces of YS 20-20.
This airplane placed 6th (out of 22) at Brodaks in profile Advanced, the only reason it didn't make it in the money was the pilot, the airplane is very capable of winning Expert under most any conditions. This isn't just my opinion as a couple of Experts have flow it.
Hard to believe isn't it...
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and where is the super charger installed ;D
Wondering how big of a prop this thing can turn.
Martin
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Hey Bob : I had to choke down a McCoy 29 to get it to run and choked it down to a piece of 1/8 tubing for an intake and it still ran like it wasn't choked down at all.
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Bob
After seeing your photo of how far the nylon screw was in the throat ,
I decided to give the 40 another go, four flights nearly all the same,consistant
nice smoke trail,draining the tank,no stopping at strange places in the pattern.
I only run 5% nitro and I am only using 2.5 oz's for a 6 min flight,will try 10% on
next outing,I also had some vibration issue's before, they seem to have gone as
well,TT prop 11.3 x 6.5 works well.Lap time's did quicken up at the end of the flight
doing 5.1 sec at the death.The only thing's I noticed were.,it was a bit soft as it
left the ground but unloaded within a lap to about 5.4 sec and it seems to go soft ( richen
up I think) on the sq eights at no time did it sag in its run.I had flown a pipe model
the week before with a OSVF25 in a Vector (at the request of the owner) and noticed
how good it was with a one speed run,the Saito 40 seems to give a similar feel.
Mods to R/C carby as per your instructions,tank as per yours and prop.
Thanks
Paul Allen
Australia y1
Bob,your mod to the carbs using the OS needle valve with spigot,I measure 4 mm x .5 pitch
where did you find a tap?
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Hi Paul,
Don't have the tap info in front of me, will check tomorrow and get back to you. Thinking I found them on Amazon but that might have been the exhaust thread taps I bought for either the 40 or 56.
I see about a 0.2 second speed up from take off to quit.. I did discover that running rich will increase the difference. From your description you may have been a click or two rich. This is strictly a guess as I've never ran a 4 stroke on 5%.
Will get back...
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What I came up with when I measured the needle assy was M4 X 0.5 which is what I ordered and it fits. Still can't find anything on who I ordered them from but remember I didn't have a real difficult time finding them, may have even been eBay.
Hope this helps..
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Thanks Bob.
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What I came up with when I measured the needle assy was M4 X 0.5 which is what I ordered and it fits. Still can't find anything on who I ordered them from but remember I didn't have a real difficult time finding them, may have even been eBay.
Hope this helps..
M4 X .5 seems to be a bit nonstanderd. McMaster Carr listes M4 x .7 or M4 x .75 Anyway was just crusing the board and saw this post. I have had good luck getting tools, control line wire, taps and drills, nuts bolts and screws from McMaster Carr. They have been fast and reasonably priced. :)
http://www.mcmaster.com
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John
Metric Fine thread.
Bob
Found a supplier in Australia.
Thanks again