Hi guys,

As my eyesight is aging I need a bigger trainer, and I'm thinking of a Boomerang .60 converted to electrickery.

I'm leaning towards installing this redback .61 motor and esc, and running it on 4s. Do you think it's enough or should I go bigger?

Originally Posted by SmokeyRobinson

Hi guys,

As my eyesight is aging I need a bigger trainer, and I'm thinking of a Boomerang .60 converted to electrickery.

I'm leaning towards installing this redback .61 motor and esc, and running it on 4s. Do you think it's enough or should I go bigger?

I think you'd do as well for fewer $ with a Turnigy G60 and a Plush 60 ESC, and put the savings into a couple of packs. You can choose the G60 in several Kv (400 or 500 would be the options) depending on prop size (biggest that will fit with at least 1" ground clearance) and cell count. Also, the higher weight will help with balance replacing the .60. For a .60 size trainer that's going to weigh over 8lb, 5S or 6s would be a better choice than 4S.

But pick the prop you want to use first, then decide on Kv and cell count.

Originally Posted by SmokeyRobinson

Hi guys,

As my eyesight is aging I need a bigger trainer, and I'm thinking of a Boomerang .60 converted to electrickery.

I'm leaning towards installing this redback .61 motor and esc, and running it on 4s. Do you think it's enough or should I go bigger?

With that motor and ESC you should start with a 6s LiPo and APC 13x6.5e prop. Choose the LiPo MAH for the correct cg.

Maybe a 5s LiPo would be ok with a larger prop but I think that 4s is too low voltage for a 60 size airplane.

.

Thanks guys,

I really have very little electric experience, so this is more than a flight trainer, it's also a system trainer

Originally Posted by RC Man

With that motor and ESC you should start with a 6s LiPo and APC 13x6.5e prop. Choose the LiPo MAH for the correct cg.

Maybe a 5s LiPo would be ok with a larger prop but I think that 4s is too low voltage for a 60 size airplane.

.

Have to disagree with a 13x6.5 on 6S with a Kv=650 motor that weighs only 230g. It's likely to pull over 65A/1300W, well over what is already an overly optimistic power rating for such a small motor, and also likely to kill the bundled 60A ESC. And 1300W is way overkill anyway for an 8lb trainer with a huge wing.

@Smokey, if you already have the model, let us know what size prop will fit with enough ground clearance. And I like your system trainer approach, my poor old Kadet went through about 6 different power systems from 50-150 W/lb before I sold it.

Originally Posted by scirocco

Have to disagree with a 13x6.5 on 6S with a Kv=650 motor that weighs only 230g. It's likely to pull over 65A/1300W, well over what is already an overly optimistic power rating for such a small motor, and also likely to kill the bundled 60A ESC. And 1300W is way overkill anyway for an 8lb trainer with a huge wing.

@Smokey, if you already have the model, let us know what size prop will fit with enough ground clearance. And I like your system trainer approach, my poor old Kadet went through about 6 different power systems from 50-150 W/lb before I sold it.

Scirocco,

At the risk of sounding like I should be on another type of web site, about 8 1/2 inches

Smokey

So let's assume you're looking at about roughly 800W input poweras a target, with a minium of 700W . You can get 800W on 4S pulling about 800/14.8=54A, on 5S @ 43A or 6S @ 36A

It also means from a power handling point of view, ignoring weight and balance for the moment, that minimum motor weight should be about 270g, based on average motors comfortably handling 3W input power per gram motor weight. But depending on where you can mount the battery, you may find a motor a lot heavier than 270g helps with balance without resorting to lead weights.

Assuming decent efficiency of 80%, 800W in will be 640W at the prop. That will spin a 14x7 prop at about 8300rpm, or a 15x8 at about 7000rpm. In both cases, that is enough for a pitch speed of about 60mph - about right for a big slow trainer

As you can use a 15" prop, you could manage with 4S using a 15x10 with the Turnigy G46-550 for about 750W in, or the G60-500 for about 720W in( also 15x10).

Go to 6S, and the G60-400 and 15x8 are an option for about 820W, or for a bit of overkill around 960W if you wanted to stretch to a 16x8 .

The G60-500 gives a lot of flexibility, eg on 5S from 700W in with a 14x7 to 950W with a 15x8, or on 6S with a 13x6.5 for about 850W.

That might seem like a lot of options, but the next thing I would be doing is look at where I can put the battery pack and how much space there is for it. Once you know what sort of pack fits and how balance is starting to look, motor size and Kv largely follow along.

Originally Posted by scirocco

So let's assume you're looking at about roughly 800W input poweras a target, with a minium of 700W . You can get 800W on 4S pulling about 800/14.8=54A, on 5S @ 43A or 6S @ 36A

It also means from a power handling point of view, ignoring weight and balance for the moment, that minimum motor weight should be about 270g, based on average motors comfortably handling 3W input power per gram motor weight. But depending on where you can mount the battery, you may find a motor a lot heavier than 270g helps with balance without resorting to lead weights.

Assuming decent efficiency of 80%, 800W in will be 640W at the prop. That will spin a 14x7 prop at about 8300rpm, or a 15x8 at about 7000rpm. In both cases, that is enough for a pitch speed of about 60mph - about right for a big slow trainer

As you can use a 15" prop, you could manage with 4S using a 15x10 with the Turnigy G46-550 for about 750W in, or the G60-500 for about 720W in( also 15x10).

Go to 6S, and the G60-400 and 15x8 are an option for about 820W, or for a bit of overkill around 960W if you wanted to stretch to a 16x8 .

The G60-500 gives a lot of flexibility, eg on 5S from 700W in with a 14x7 to 950W with a 15x8, or on 6S with a 13x6.5 for about 850W.

That might seem like a lot of options, but the next thing I would be doing is look at where I can put the battery pack and how much space there is for it. Once you know what sort of pack fits and how balance is starting to look, motor size and Kv largely follow along.

Thanks mate, some of that sounds like double dutch to me, but it gives me something to research

It'll fit a 6s 5000mah pack (about 850grams) fairly easily.

In that case, just go with the G60-400 and a 15x8