ORIGINAL: a1pcfixer
ORIGINAL: jsallade
Actually that 12.5 x 13 prop is about 85% of the minimum load recommended for this engine.... So with good lubrication and ventilation... I'm betting on a midair or other ''unfortunate end'' to that airplane before the engine gives it up! Just a prediction. An 18x6 is about the equivalent in the other direction (overload/above spec)... wonder if that would cause a failure first under full throttle conditions or the smaller prop would??
Of course, I did say with adequate ventilation and lubrication... we don't know if that is happening or not!
Actually that 12.5 x 14 is BELOW what DLE recommends for the DLE20 (14 x 10), which will put it in excess of 10,000+ rpm's, and often!
An 18 x 6 is ABOVE (17 x 6) what's recommended. So I'd vote on the smaller prop &/or a mid-air as being the demise of that model.
As for lubrication, he'd do good to increase it to say 25:1.....but if he's using Lawncrap all bets are on eng seizure
My good side says everything about that setup & style of flying is wrong.
My bad side though says they're having loads of fun and a mid-air would just be awesome!
If ya clicked on his user name to bring up his profile, then scan his other messages, you'd find he's posted other videos with the same chaotic flying.
They're always having a good time!
It's about the load the prop is putting on the engine. He's running a TON of pitch, making the load significantly higher than one might first consider when looking at only the dia. of the prop he's running. This is a pretty unusual prop not normally used - but fitting in his application (pylon racing). Whoever wrote the recomended prop specs. would be much more likely to use prop examples that are more mainstream. Not saying this prop is correct, only that it may not be as far out as it might seem at first glance.
Using the 2" of pitch = 1" of diameter guideline used for maintaining similar loads while playing with prop sizes, and starting with a 12.5x13, you could drop 4" of pitch while adding 2" of diameter and come up with 14.5x9.