|Dec 24, 2002, 05:29 PM|
Best Lightweight Brushless Power System for Lil Hornet?
I have a Lil Hornet as my testbed and I have tried a bunch of different motors in it. I am going to build a new one with some mods to lighten it up some. I like the way it flies with the stock Johnson 250/MG-1, but wanted some more power (of course!) I have tried Graupner Speed 300s/GWS -B and Cs on it and while they give more power, they need bigger batteries, have a higher wing loading and it just flies different. Is there a brushless solution out there that is light enough to compete with the 250, but have more power? I have been running 720 NiMH packs with 7 and 8 cells and would like to keep them if possible. I have a bunch I have not made into packs yet also. I am not sure I want to make the jump to LiPolys yet. I guess that limits my choices some.
I have a Hacker B20-22S/Phoenix 10 ESC and am quite impressed with it. Unfortunately, it needs fairly big (HEAVY) batteries. Maybe a -31S or a -26S? Any thoughts?
I appreciate the information on this site. It has let me progress from flying a stock Lite Stick to a garage full of parkflyers that all fly well - - and with almost no wasted $$ on bad combinations!!
Thank you and THANKS Ezone!
|Dec 24, 2002, 05:35 PM|
The Astro 010 with one of the new gearboxes from earomicro. On the cheaper side of BL motors, and I only fly mine on the 720's. (though I like 10-cells) It's also a great direct drive motor for a fast 10-13oz plane.
|Dec 24, 2002, 06:02 PM|
mel, use your hacker 22s and prop it for 7 amps, motocalc shows 12.7 ounces of thrust at 6.7 amps with a 9x4.7 with 8 cells 720 nimh, or you could put the hacker in a gws gearbox and play with bigger props to get more thrust/less speed, the 9x4.7 has a pitch speed around 30 mph, which is probably PLENTY fast for the hornet, just a thought before you dish out for another brushless, you could even go with 7 cells and a 10x4.7, also if you dont have a whattmeter, you can find cheap DVM's that can measure current up to 10 amps, just so you have a beter idea
just a thought as im thinking of buying a 22s and doing pretty much the same thing with it
|Dec 24, 2002, 07:26 PM|
That Hacker is a real nice BL, but is going to require ampere that will suck those 720's dry pretty quick. I love the 010 with AeroMicro\GWS gear drive system, cheap and light, also fairly simple and cheap replacement parts. With the CC 10 amp ESC all you would need is the 010 motor, but would still suggest for the small amount more getting the entire kit with gear reduction, motor and ESC.
Do not know the Lil Hornet specifically, but would guess a sporty semi-symmetrical small plane. Below are much more forgiving Motocalc numbers for those 720 nimhs you have with an 8C setup on the 4.43 GWS drive and an 11 X 8 GWS prop, good performance with plenty of torque for any sport plane using that battery pack.
Motor: Astro Brushless 010 14T#25 #801G w/o G.B; 2300rpm/V; 0.27 Ohms; 0.15A idle.
Battery: Sanyo 720AAA NiMH; 8 cells; 720mAh @ 1.2V; 0.04 Ohms/cell.
Speed Control: Castle Creations Dragon 35; 0.0055 Ohms; High rate.
Drive System: GWS GWS/EPS-300C-CS; 11x8 (Pconst=1.18; Tconst=0.995) geared 4.43:1.
Airframe: My Tiny X; 220sq.in; 11.1oz; 7.3oz/sq.ft; Cd=0.041; Cl=0.31; Clopt=0.47; Clmax=1.1.
Stats: 47 W/lb in; 39 W/lb out; 13mph stall; 20mph opt @ 66% (64:25); 25mph level @ 80% (44:46); 814ft/min @ 26.9°; -206ft/min @ -6.6°.
AirSpd (mph) = 25.0
Drag (oz) = 1.4
Lift (oz) = 10.8
Batt Amps = 2.9
Motor Amps = 2.9
Motor Volts = 8.7
Input (W) = 25.0
Output (W) = 21.5
Loss (W) = 3.5
Temp (°F) = 90.3
Motor Ef(%) = 85.9
Motor RPM = 18036
Elect Ef(%) = 77.4
Prop RPM = 4071
Thrust (oz) = 4.6
PSpd (mph) = 5.8
Prop Ef(%) = 66.8
Total Ef(%) = 51.8
Time (m:s) = 14:57
AirSpd (mph) = 0.0
Drag (oz) = 0.0
Lift (oz) = 0.0
Batt Amps = 3.9
Motor Amps = 3.9
Motor Volts = 8.3
Input (W) = 32.6
Output (W) = 27.1
Loss (W) = 5.5
Temp (°F) = 101.7
Motor Ef(%) = 83.1
Motor RPM = 16538
Elect Ef(%) = 72.0
Prop RPM = 3733
Thrust (oz) = 10.7
PSpd (mph) = 28.3
Prop Ef(%) = 0.0
Total Ef(%) = 0.0
Time (m:s) = 11:02
|Dec 24, 2002, 08:19 PM|
Bonjour Monsiuer Mel! Well........That was a whole buncha data for us old fogies to fergit!!!! Thanks K.B. Are ya gonna crash it inverted or upright?? Merry Christmas! Best Regards
|Dec 24, 2002, 08:53 PM|
I don't know for certain, but maybe one of the 1215 Mini-AC motors. I'm not familiar with the plane, but the 20 turn looks okay. Just offering a possilble motor, don't have any data on it!
|Dec 24, 2002, 08:54 PM|
Ditto on the aeromicro converted GWS and astro 010. Fits your requirements nicely. The whole setup (gearbox/motor/ESC) weighs about 1/8 oz less than the same setup for a stock 300 motor and 10amp controller. I have the 3.75 to 1 and on 8 720 nimh AAA cells pulls around 4 amps makes 13-14 oz thrust with a 10*8 GWS prop. There are several GR available, so a little testing is in order to find the best ratio for a particular app, but guys seem happy with the 3.75,4.?, and 5.33. This motor seems happy with all these setups.
|Dec 24, 2002, 08:56 PM|
The regurgitating of info was easy, copy\paste Actually, I love the info or raw data, makes it easier to see what is actually happening with a given setup.I am not certain if I would want to know the attitude of my plane prior to my next crash; I would most likely try and never get in that attitude making for very boring flying
|Dec 24, 2002, 09:10 PM|
I'm glad you posted asking about a Lil Hornet power set -up
I'm in the proces of rebuilding mine right now with some lihtening mods etc.
I'm also considering buying the Astro .010 but felt it more apropriate for my Tiny and not so much for the Hornet.
Figures and numbers aside, I was the impresion that the 010 is closer to a 280 than a 300. I guess I'll know once I get it
In either case, I have an airframe for it depending on how it performs.
My Hornet was very happy with a timed GWS 300 geared 5.33 to 1 I used a 8x6 or 9x7 with 8 350MA nicads or 8 720 Nih cells.
By happy I mean loops from level and some vertical with 10 minute flights on the 720Nih packs.
Of course I want more power too
I'll try to post pics of my mods tomorrow.
|Dec 24, 2002, 09:16 PM|
Poobs, the 010 is definately the equal to a speed300 if geared right (I ran them side by side, same RPM with 8 cells but less current on the 010, better rpm on 10 cells,6 amps, and forget about the current with the speed 300). Are you wanting to stay with that size prop, if so the lower gear ratios would be a better match due to the lower KV of the 010 vs the 300.
|Dec 24, 2002, 09:37 PM|
Looks like I'll need two 010s One for Tiny and one for Hornet
So you are saying that the 010 beats the 300 even when both use 8 cells??
What gear ratio?
I'm thinking to order two ratios...one in the 3s and the other in the 4s
|Dec 24, 2002, 09:45 PM|
with the 3.75 to 1 010 vs. the 5.33 to 1 speed 300 on a 10*8 I got nearly identical RPM but at much less current for the 010 (can't remember but I think it was like 2 amps less on the 010). No contest at 10 cells (granted I was using 720's and would not run 10 on a 5.33 speed 300 for very long). bottom line is you can use 10 720's and have more power. Of couse you could go with an even higher (300D?) and maybe use the 300 on 10 720's, don't know, don't plan to find out. I really wish perry would do a side by side comparison of power and RPM for the different combos.
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