The 810 rating of the G-10 seems a little low to run with a 3 cell setup and a KR timer.  At full charge you are looking at only 9K rpm.  The KR timer needs head room to control rpms.  Something in the 1000 to 1100 KV range would give max at 12K rpm or so.  This way you could set the KR for 9 to 10K.  Others may a better feel for what will work.  At the expense of losing nose over motor protection a simple timer may be a better fit a 3 cell 810 KV sport flying setup.  Turnigy recommends a  12 x6 prop.  A 12" prop may be a ground clearance problem.

Hi Phil, John is quite correct about the kv rating. It's too low and the G10 is too big as well. The .15 size electric C/L is a bit of a hassle size and their are quite a few options if you check out the List My Setup sections. Some time ago, Will Moore wrote in Stunt News about using the weight of the motor and the kv to select one for C/L. I've been playing around with .15 size stunt trainers lately, and I find that you need a motor that weighs around 75 to 85 grams with a kv of 1100 ~ 1200. I modified a cheap Lanu P2B Trainer and used the E-Max/Arrowind 2220=05 motor with an APC 9 x 5 E-prop on a 3-cell 1300 mAh lipo. It flew quite well but only ran for a good 3.5 ~ 4 minutes, so it would need a slightly bigger battery for a longer run. Another way to go is with a slightly smaller higher kv motor with a smaller diameter prop, like a 7 x 6 or 8 x 4 turning higher rpms. You would then need a kv of around 1500. Dennis Adamisin did a lot of work on the Brodak systems and you can download the pdf file from their website that shows the motor, prop and esc to use for many sizes of model.

On the timer thing, a governor system is always a better way to fly.......even on a 1/2A! Losing rpm as the battery goes down and when you do a hard turn is pukey! This is why I developed my KR Governor timer. I did make timers that increased rpm over time to compensate for the volt drop and winding resistance problems, and even made one version that measured the voltage and added throttle. It was still pukey......like a real bad glow engine that runs away on the downhills and dies on the uphills.

One more thing, the 50 A esc is way too big. You need a maximum of around 20 to 25 amps. I could only find a small 30 A Hobbywing esc locally so I used that. It was still small and light and worked fine. Mounting the motor is easy.....just saw the whole nose off the model to get rid of those heavy engine mountings and ply doublers. You don't need them. Use some 1/16" ply with balsa and just make a new nose. I've added some pics of my modified Lanu trainer. Shout if you need any more help. Sounds like a nice project.

Keith R

What type of lap time should a Jr. Ringmaster fly? 

50 ft spectra lines is my current plan.

Phil

Fast enough to keep the lines tight, but yet slow enough you can control it.   I've been told 55 to 65 mph is about ideal for most stunt models.

so...3.5 sec per lap is 60 mph on 50 ft lines.

Hmm...

Phil