Tester 6

My Feedback: (1)

Has anyone done a brushed motor "E" conversion for the DynaFlite Butterfly Motor Glider.
Mine is 3.1 Lbs and 99" W/S. It normaly takes at least a 15 glow engine. I just want to
climb to soaring altitude.

Tester 6

ray foley

hi there:

Although I have not done the conversion on a butterfly, most 100" std class sailplanes (and the butterfly is not too different from a sailplane) will respond nicely to the following:

one of the axi 28xxyy series of outrunners, a CC phoenix 35 ESC with Castle link, and a 3s lipo or 10 cell nimh pack (or several packs) for power at 2000 mah or so, a Cam folder prop 12x8 or so from HL, and a Triton Charger will round out the equipment list very nicely.

I have been flying Epower for about 18 years, and the above list is a great way to go for success. For a plane at 3.1 lbs figure that you will add about 12 to 16 oz to the plane.

For reasonable leisurely climb you need 50 watts per pound of plane. So figure 175 to 200 watts minimum. Bump that to 100 watts per lb and the phrase "climbs like a homesick angel" applies quite well. Even more.... oh,dear me!

The folks at HL can get you hooked up very nicely. IMHO, dont let them sell you a jeti ESC, buy american, buy Castel Creations.

ciao -rjf

chrisrosenkrans

I just completed an electric conversion of my butterfly. I ended up using a nippy black 2510/14 ($56.90) brushless motor from Hobby-Lobby.com, CC25 amp esc and 2 1500 mAh 7.4V LiPo batteries wired in parallel to get 3000 mAh. I am also using a 11X4.7 APC prop. This setup pulls 15 amps.
The only problem with this setup so far is that I had to add a lot of weight to the nose to get the plane to balance. My total weight ended up being 70 oz. Lucky for me the motor is good for sailplanes up to 70 oz. I flew the plane this morning and it flew just fine with the extra weight. My plane is a slow lumbering giant. It has a slow climb rate and glides real well. This is the mission of my plane and I feel I have achieved that. The only change that I am going to make is to replace the LiPo batteries with an 8 cell 2600 mAh Nicad battery that weights just as much as my current set up.
Before I did the brushless setup I used a brushed motor on a gearbox with a 7cell battery. This setup worked just fine for one flight. My ESC had a break and it damaged the gearbox. If you would like some more info about my brushed setup I will give what info I have.
Good Luck

chrisrosenkrans

Just finished up a 25 minute flight on the butterfly this morning. All I need now is a lawn chair and the help of some thermals and I will be able to stay up all day. This was the first flight on a new battery pack (2600 mAh NiMH). As the pack goes through a few cycles I think I can get a least 30 minute flights. My flights are at less than half throttle and with this new battery pack I have a lot more power than my old LiPo setup. My Butterfly is very heavy it weighs in at 70 oz and is a beast when I try to hand launch it, but with the new battery I have more than enough power to get this bird airborne from the ground. The reason my plane is so heavy is because the brushless motor I have up front is so light (2.2 oz) and to get the plane to balance I was putting 18 oz of weight up front. So I dumped the LiPo battery (7.4V 3000mAh) and 10 oz of weight and had an 18 oz 8 cell NiMH made to use as my power source. That is where some of my overweight issue comes from. I also put on some 4" tires which are 4.3 oz more than my original wheel choice. All in all I am happy with my results, and look forward to many more relaxed flights.

rccrasher1967

chrisrosekrans what size of brushed motor did you use in your butterfly? I have one with a 25la on it and am tirerd of the glow thing . and what size of speed controle didyou use?

John 38

I would add to ray's recommendation that the selected motor should have a Kv no greater than 1000 to turn the big folder props. i have a butterfly and this thread is sparking some interest in me to go electric with it as the curren tired OS 15 just about gets it aloft- where it hangs on thermals just nice.
I think I would look at extending the nose about 2 to 3 " to get motor and battery forward and CG right - I hate dead weight.

I gave up lawn chair flying - tooooo relaxing !!!

john

rccrasher1967

thats a new one I have seen mowers flying but lawn chairs [X(]? what size of motor did you use?

UltraBob

I still fly mine often. When first built, (five years ago), it had a Master Airscrew brushed 05 with a 3:1 gearbox, 12X8 folder and a 7 cell 2400 nicad and flew beautifully at 64 oz.
About 3 years ago I installed an AXI 2826/12 and a 3 cell 4000 lipo and lost 8 oz. of weight but now flys forever. Like Chris said, get out the lawn chair and relax.

John 38

rccr
"thats a new one I have seen mowers flying but lawn chairs ? what size of motor did you use? "

this was before advent of electric and as I struggle to remember - it might have been " internal combustion "

very low cg position and poor aerodynamics gave rise to "geniune seat of pants flying"

john

rccrasher1967

probely flew about like i used to ! it stayed on the ground most of the time

John 38

thought I would upload photo of "my" butterfly.
I say "my" as I never built it - bought it complete ready to fly at a model bring and buy - only had to put crystal in Rx, charge and test batteryand fuel her.
Engine is an old OS15 - underpowered, but on nice low wind days - ok to get up into thermal territory where the butterfly struts its stuff
john
ps , the lump below the engine is lead to get cg right. nose is short and would suit lengthening for electric and battery aand getting cg ok
[img][/img]

rccrasher1967

wouldnt a battery in the nose ballance it ? i have about 5 or 6 oz plus rx battery under the tank right now

John 38

RCC,
probably, but sticking 2 oz lump right out minimized weight req'd and minimised weight penalty

really needs bigger ( and heavier ) engine as it is underpowered. But am holding off pending going electric on it

captjckirk

I have two Butterflys, one glow powered, the other electric, never fly the glow anymore, don't have to wipe the gunk off it. Let me start by saying you need to extend the nose, mine is 8 3/4" from the "windscreen". That gives you plenty of room for the batt, it can be moved fore or aft to balance, no need for lead. I removed the landing gear and hand launch. also am using carbon fibre rod listead of the steel rod that comes in the kit. It now is lighter than the glow powered one. I used an AXI 2826/12 outrunner motor, Advance 40 plus ESP, a Aero-naut 11/6.5 folding prop, and Thunder Power TP3S2P 4200mha 11.1v lipo batt. May sound like over kill, but I compete in Climb and Glide with guys that use glow 40s in their Butterflys. Have had a 32 min flight with this combo. The Butterfly is a "Most Fun" to fly plane, and with electric power it 's even better.

captjckirk

Explaination of my 32 mins. That is with power OFF, just as a sailplane.