xalm04
Posts: 76
Joined: 9/13/2004
From: Quito, ECUADOR
Status: offline
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Last weekend finally I tested my electric converted pattern plane  . As some of you may have read I was asking for advice since I was converting a glow pattern plane, and I wanted to know the best suggested configuration to make this. My Milenio L was originally eqquiped with an OS 140 engine, and after long deliberations with my club buddies I decided to equip it with a Hacker C50 14XL, an Acro 90 ESC and 4200 mAh Thunder Power LiPos, and this configuration weigths 4960 g, so just 40 g under the feared 5 Kg. The change was huge!!.
I tested its first 2 flights with an APC 22x12W prop..... plenty of power for this altitude, as my predictions confirmed, the electric motor delivers more power since it doesn´t suffer from less oxigen to burn as the glow engines do. The watts pulled from this motor were not impressive (2100 W), maybe because there is less air to push (less pressure at 9000 feet of altitude), but I still had 5800 RPMs. However the plane behave excellent in uplines. Downlines were other story, because I setted the ESC with 30% brake, so for me it became unconfortable to have such low speed at the exit of some maneouvers, making it quite dangerous also  . Last flight I tested a 21x13W prop and it behave even better, more power was available, and less capacity used (just 2350 mAh). I have to get used to manage more the throttle curve and stick, and then maybe I can use a little more capacity to have a constant speed pattern routine. Next week I´ll try to fly without the brake setting to see if it is better for me, at least for the first flights.
I want to thank all people that helped me and all their advice, specially Chad Northeat, patternflyer, ExFokker, and of course Don Shulman. Your advice were unvaluable, thank you guys!!!.
As a conclusion electrics is definitelly a choice for high altitude pattern practice, and I believe I started a crisis in pattern society in the andean lands....  in our track to Argentina 2007 WC. I promise to post some photos next week, if everything go well.
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Xavier Almeida
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All Forums >> Electric Aircraft Universe >> Electric Pattern Aircraft >> Electric Pattern at 9000 feet of altitude...done!! 
Electric Pattern at 9000 feet of altitude...done!! - 
RE: Electric Pattern at 9000 feet of altitude...done!! - 
kidding I had to say something lol... those are pretty good results. The only thing you are losing performance wise when you climb in altitude is prop efficiency. I normally fly at sea level, my dad lives at 4500 msl, so when I go up there I usually have to go up in pitch with one of my planes... from a 20x13 to a 20x15 to get about the same amount of performance. 
