RC India

I have been using 1/2A Engines for sometime now. For a Cox starter spring are available for easy start at the field. Though at a cost of partial 5=10% loss of output they do a good job. But I had a tough time starting the TT GP 0.07 with a full scale starter since it does not have a starter spring and its just not ready for a hand flick unlike my all other engines. Need for a 1/2A starter was felt very urgently. There is one available with Tower Hobbies of Sullivan Brand http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCLY7. While I might order the same in near future thought might as well make one for myself.

(http://beseenontheinternet.com/VAHS/images/ClipArt/Hornet_Starter.JPG)
Was having a 500 Size DC Brushed Motor of 3.2 Volts High RPM. First I was wondering if I could create a gear mechanism to reduce the speed and increase torque to be used as 1/2 Starter however I would have had to use the same with a single cell Lipo and would not have been able to use it directly off the 12V Caddy.

Taking inspiration from Roopesh and others who are successfully rewinding brushed motor and using it at a different voltage level and torque. Decided to rewind it and use it for a 12V application and reduced RPM and higher torque.

Opened the motor and it had a 14 Turns per pole and it was a 3.2 Volts motor. Removed the winding's carefully. Gave it a 55 Turns per pole with a five strands of thinner copper enamel insulated wire (Final gauge would be 1/3 the original gauge).  

(https://lh3.googleusercontent.com/gHODYgmDZLj3Bkjuhgj-pWjMtZbLoNCFq-pzf7CToC4=w858-h643-no)(https://lh3.googleusercontent.com/HdFkkOfbl82_uw1PINASW1i8o3pjWwNt1aWy0PIHXCU=w858-h643-no)(https://lh3.googleusercontent.com/oA2mZyiLaxH__idylGzEPEfTlTzBVVqwMDjYE-P_24Q=w858-h643-no)(https://lh3.googleusercontent.com/_o1_W5QQyK7Y4fzsIhGRPYGUjlZVlvR9tRaDpq4nGLI=w858-h643-no)

Used a Glue stick large base screw cap for the spinner cup with Grub Screw Prop adapter of the size of motor shaft to couple it to the motor.
(https://lh3.googleusercontent.com/pgJHGm9W-7L6hcrCSIB3VF2R4nzPrw6ikFaXNE-ZIlc=w858-h643-no)(https://lh3.googleusercontent.com/wuBCHIbZscogRYUJUGchI1VN5sgAsa2u_qS_2HWmAok=w858-h643-no)(https://lh3.googleusercontent.com/UGf5W2HuBRRIJiKtQh-wiVA6rNRrKfXQJgrZ-0Uh_ZE=w858-h643-no)(https://lh3.googleusercontent.com/jT_XmIdvcGIeD5PVwlYxQvfQkDkqaukIjUTWn5ALioA=w858-h643-no)

Did a test run and was running with good torque and desirable speed and at no load it was running absolutely cool for more than a 5 Mins before some warming was noticed on the can. May be with load it will heat up but I need to use it for just few seconds of Starting bursts. Now I need to suitable modify some thing of rubber to be used as Rubber Spinner cup. Lets see if I can totally discard all my starter springs.

Nice and motivating.

Thanks Saurabh.

This is a DC motor brushed. Even then this is a three pole motor with two magnets. This is also wound in three coils. Each coil is wound in each pole all clockwise or all anticlockwise. Then they are connected in DELTA and connected to the bushings of the commutator. Commutator and brushes does the job of ESC. Each coil wih 55 turns have been wound here arbitrarily.

Close up of scratch build switch with two metal leafs between hard rubberised foam.

(https://lh3.googleusercontent.com/68Dg5CkgqFqIFHdPSi4H8QMX0knJZqLPXKD0Ub522HfFSLm5n-RlPqV_cVz71WEnMjp78y7w5e6DyuvB1fRXPZ4H8jL4mky7sV1WwZesETmOLaJCK-dxRrtdVzy_nuV0A17VbiGINNd7COGB_N1v58QvTFsjVLCC3hbGDS01BNIInvNvN9p5vJFQJCxvXwHEzqS6zcCCvoefigmcIUYWXUjH3XyeG9u9LEImTPCtHDyd1MhqIqhJXiKit54rJMZ_Bm2Tlwbeyytd-yeoxxmxGi9TBf4mMulGqsyB_TKf6CPFZCBBemD5m16u5E5ZNX08JSP7GdDvoD7EzrO-JJyoLsTxEbaRqMKvO7rgVUh0fazl_5ve6adav7F0JbFob6KZ_69pUSmiA0Lq0Ed0EFF0Q8Wy03DVGuQFTNdmNYYcoSUOcEEdB3hE0eIjEIy926WopwKbg83MAi01SAwR-b9c9XsfXgfxxzLPfFkiK-fFJJCg40k3il9pBhp1ZbxiJO9RJdCjNwBT5-se7_kFFXgX7qXefSUIOZft1Kiy2NjzsXA=w720-h540-no)(https://lh3.googleusercontent.com/nvytXDGfwDHGuj1XzfhJCBS_i35fS33NyjysV3O82MlhClE7bbkLZOCa7af8bJ_g6GLf9UNyP-O1WuyMbMfYR46pvwd6fCMPwuJ2gYYXocm8N0Du94i7ZMQ8MRQN2vs0AxivIVmFxavnnS75SVt8tdMTzD1l8wS8I0xgaoHcBylTULDSa09CtNSS0IJrr7j7Idsm8BXs-1USv3XPq7NNgrdfk40lWuAFyoLVaq6Hx7VZrfPUZQ-yc79T-O0Sakf-fP7dalh-XRfnkFYSgjF2wPmTWwrEa3EMBsNkpUipD9vsdPmiVefcaqI5giv5J-Y4A4GAcVt2RqBE8G8mOAgSxmP6O4t4ihgYKfNt8g00q6rB6OCH1Jwze49MFa-Z_XEXg1718IikD69loP4I51W3KFpGaRIbliSrpW9Rzigc2FCNXWZa49wfVirHoD319REjmOl_ygJLtj7VxH9AXTQjugNGxOBjltnen53Nqlesa8o9pLFhNUVqQETS_3Ni13PNq61CrDmpjGQf9R5dbbBz5ybHOaeLbNHiC7OEDkBgI88=w744-h558-no)

Finally Done with same hard rubber foam for the spinner cup

(https://lh3.googleusercontent.com/aeKAXE_5yjTlrjGIb8Veh7_egvIZPmlOYzAYewPyImbjtOgXMjjZQSQoJvRnR2850jTlwAgUNtXzIkZm3OhkOP5cjIIVWJCwDIC1qH5rcBWNYnhl4J9VyXZeczFd8F7qspBEZyLw43sj3O_P_HFDX1d0bBM6jI_dmy-Qc1MnDEHd3UK96sJ3nvR2Hr0UTZb-8kUd2WruLclw2H4YuoJy-1Lzj4YPaOczTOURozQODMACi5u3HyNR5KDNRnACyncdaCgT3FNH9AdRn_M0d5ISKbOErHJWElOSQkIEcbQ7bauKCqkQoErTxtSUl5TwUup_C4hUKPPjR5J8Y2LLchCqLbGW4uGpEDEuFRn_JOvYB8gbsAi_r04rCF4fbS7xp3Pjwg_OoDVY7Yn6lRvYwnAunfByxkZ8Fpi627LGiTS68a_THy9A4CRHCJNu39HqL2B0ppqYgw8pvDI5ceDwjgybBdw04ERe8ikLaOK2NoCON02n_-k4mCGDeoVVkpy-ZYVhYVLKKX2sCyPpg7hc1M1Ke2St6BIFSImwokXl14a4LNk=w720-h540-no)

Tried it on Cox as well as TT GP 0.07. With a 3S lipo it's RPM is very high and it's able to turn cox almost at WOT RPM. TT is slightly lower. With a 2S it's perfect RPM for Cox and able to spin the TT too.

WI'll try to fire it up with booster but I am getting  a feeling I need to increase turns to 70 per pole to use it effectively and with good torque on a 3S lipo or Caddy 12 Volts battery.

Videos are coming up.

Very innovative and useful build.

Is it possible to replace the rubber cone in a regular starter with a cone suitable for a cox? Just an idea.

Yes sir it's very much possible to use a regular starter with a 1/2 A starter cup but it's rarely available and you risk spoiling engine in case of fuel lock regular being too powerful for 1/2 A engines. I was using the regular starter for TT till now.

scratch building a 1/2 A starter cup for regular starter is lot easier surely if that was your question.   ;D

Got it Col. I agree there is a danger in damaging the engine in case of fuel lock with a regular starter.
Please share source for hard rubber foam as I am also interested in making one for my cox engines.

Sir mine came inside  the OS engine box packing which I had bought. Even a rubber Chappals have same foam. You can use the ones which comes with heals.


PS :  Now all my starter springs of cox have become spare. :D

Thanks Col. for the info.

Just a Short clip.

www.youtube.com/watch?v=gS311PZVbQM

Lovely.
Faster than the spring starter!

Great Sandy

Thanks Iyer Sir.

Wanted it more for the TT since no spring starter for it. Came as a boon to the Cox too and starts a Cox in a breeze. Removed all my spring starters from Cox :-D

Major Advantage is that Fingers no more being hit by a Spring Loaded Prop.  ;D