critterhunter
Posts: 2510
Joined: 9/24/2004
From: Brook Park,
OH, USA
Status: offline
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quote:
ORIGINAL: alouette3
Here is my SO.1, minus all the gear.
I have made it from similar stuff to what Critterhunt used, EPS he called it. In my side of the world it sells under the name Isotherm.
I fly Heli's, and have got a couple of gliders... although they have never flown, so this will be my first Motorised Foamie.
The booms and fuselage have been thinned to keep weight down, although this foam is still heck of a stiff! Also put in dual aileron and have raised the motor mount.
Going to run a 1000mah 10c battery to start with to keep weight down and things slow.
Just wating on the ESC now.
Have got a 2408-21T motor,30A Flying ESC on its way, Esky 1000mah battery, x3 Esky Servos (Had them lying around).
Any Tips on what Prop would be best, to keep it slow, low draw yet responsive? (for now).
My all up weight currently is about 400-430g or 14-15oz
Any help/ tips appriciated!
VERY Nice!  I assume when you say you made it from "similar stuff" you mean something like the denser Falcon EPS foam I'm using these days (found at construction supply centers), and not just EPS found at Home Depot or Lowes. That stuff is much lighter/weaker but is also perfectly fine. FoamFlyer and just about everybody building the So and other scratchbuilds use it. If I had to buy from Home Depot/Lowes I'd opt for the pink or blue EPS. Much denser/stronger than the white, and smoother too, but not as strong as the stuff I'm using.
That 10 amp capable lipo is your limiting factor. The BP21 will draw 14 to 16 amps on say a 7x6SF (used to fly this setup on a Stryker...very fast). An 8x4E (all these props are APC) will draw I think 12 to 14 amps. Slower but very good torque. I prefered that prop on my prior So builds using the BP21 you got. 7x5 is probably around there in amps as well. 7x4 might be 10 to 12 or so, still too many amps for that pack. I'm thinking you'll need to drop down to a 6x4 and even then the amps might still be at around 10 or so. In general, you only want to draw about 80% of the amps a pack can deliver continuously. If you go by the burst C raiting of that pack you'll find it will have a very short life.
I'd get the most common universal packs most people use for Park Flyers, from sort'a small to sort'a big planes...A 3 cell 20C 2200ma pack. I fly these in all my diverse plane styles and sizes. Check out Hobby City. A HXT, Loong Max, or Zippy H (?...second best Zippy...Might be "K" or "R"  is as cheap as you are going to find a pack in that size ($23 to $27 or so), and I've had good luck with the HXT and Loong Max. Haven't tried the Zippy yet but hear good things. Think they discontinued the Loong Max. Pick whatever is in stock or you'll wait a while for it to ship.
While you are on there, pick up some HXT900 servos for $4 (The *BEST* servo for most builds. Blows away the HS55 Hitec $20 servos and most others. They'll work in small/light to most big/heavy builds, though I go to HS81 servos when very fast or heavy (9320MG servos from Hobby City are a good/cheap replacement for the HS81). Also check out the ESCs. Tower Pros (30 amps for $14) or Super Simple ($9 for 30 amps) are great. If you want even better with more options then look at the Turnigy ESCs (Sold as Pentium by others). When you want to step up in motors check out the 2409-12T that Saucerguy is using or the 2409-18 that I'm using on my So. His is faster. Mine has more torque. AND, pick up the $25 HXT balance charger. It's all you'll every need for a lipo. We love'em.
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All Forums >> Electric Aircraft Universe >> Foamies! - RC Electric Foam Aircraft >> RE: Here's A Simple & FREE First Foam Build Plan! (Part 2) 
RE: Here's A Simple & FREE First Foam Build Plan! (P... - 
