skyraider71

I have my Sig Riser kit and have decided to go with brushless power. I need recommendations for
the motor/esc/lipo/folding prop. I would like to use Eflite products because my LHS has them in stock.

BMatthews

For a casual climb and for keeping the weight down a Park 450 will likely do just fine. To that I'd add a 30 amp ESC for trouble free operation due to the over size rating and a 3S 1300 to 1500mah pack rated at 25C or better. This won't be a barn burner for performance but it'll get the model up to thermal country in well under a minute of run time. So the pack will easily have 3 or 4 such climbs per charge with enough left over for some soaring.

The climb angle and speed will depend on the overall weight of the model when ready to toss. But with some shifting around of the RC gear, motor and flight pack you should be able to hold the weight to around the lower end of the 30oz range. And with roughly 2 lbs powered by around 150 watts (14 amps and 11.1 volts) that equates to around 70 to 75 watts per lb. And that means a 40 to 45 degree climb at a fairly sporty pace. So no vertical climbing but in a minute you'll be up around 400 feet or so.

What I'd suggest is that you set up the model without any battery pack at first. But leave room in the nose just behind the motor and ESC for a good size option up to 2200 mah. Then use some weights to achieve the balance. When you got that then weigh the lump to see what you need and buy a 3S pack at whatever power rating weighs that much. Or if that's too big to fit then use some pack which does fit along with the required nose weight. If you need to lift it up anyway it may as well do something useful like hold energy.

skyraider71

Sounds good. A club mate suggested a 480 motor but I thought that might be overkill. I don't need blistering performance, but I want
light weight. I do have a 3s 2200 pack I can try. I need to know what prop (folding) I would need for the 450 set up. I'm and old nitro-head
and I know little about electrics.

zac dady

I would just buy the same motor and prop the Radian uses along with spinner.

Aquila1954

My Feedback: (1)

Well, I am building the Sig Riser 2 Meter now.

Motor: Turnigy Aerodrive D2830/11 1000kv
ESD: Turnigy Plush 40A
Battery: Turnigy 2200 30C 3s lipo.
Prop: 10x4 folding

RDJeff

My Feedback: (11)

I'm in the same boat, trying to come up with a good power package for a Riser 100. Using MotoCalc, I got a long list of motor and prop combinations, and it seems all are very expensive. This is my first real shot at powered soaring, and I don't want to sink a bunch of money in it, so I did a lot of digging, and found that what was most recommended is 70-80 watts per pound for this type of aircraft. I also read that a bigger, slower turning prop will do better. So after doing a bit of shopping, I came up with a Turnigy G15 710kv motor, and I already have 11 x 7 and 12 x 7 Graupner folding props to go on it. The motor may a bit of overkill, but the price is certainly more affordable. Does this sound like I'm in the ballpark Mr. Matthews?

Aquila1954

My Feedback: (1)

Hello;
I am planning to build a Riser 100 after the Riser 2 Meter build is done. And I am going with this motor in the plane. http://hobbyking.com/hobbyking/store...3_5_960kv.html
And probably with a 12x6 folding prop. I have the same motor in my 2 meter GP Electric Spectra glider. And it makes that plane go vertical if I use full power.

BMatthews

I'm not sure it isn't still a lot bigger than you really need. The raw motor itself is 170gms or 6oz. That's a pretty fair size hunk of weight in the nose on such a lightly built model. But while it may not be a perfect match it's not too far off on a 100 inch model. Don't be surprised if it ends up forcing you to move things back in the model to avoid adding tail weight to get the right balance. And certainly at 575 watts for max power it's more than strong enough depending on your prop and pack.

With a Riser 100 my goal would be to keep it in the lower 40oz range. After all it's a design which is best used as a "floater" due to the wing section being pretty basic. And that means I'd only need a motor that can handle somewhere around 300 to 350 watts max and then run it at around 200 watts from a 3S pack to achieve 80 watts per lb. And from browsing the Hobby King range of motors that suggests that I should be able to get that much power from a 3 to 4oz motor.

And in fact I'm looking at some different Turnigy motors for a glider I've got which up to now has been using the original can motor and gear box. One that has caught my own eye is this one;

http://hobbyking.com/hobbyking/store...ner_Motor.html

I like that it's got a nice strong 5mm shaft so even if the prop folds with on blade down so it is still going to dig in that the shaft SHOULD be able to take that much dig without bending. It's got more than enough power for a lighter Riser 100 with a max power rating of 443 watts and best of all for your case it's only 105gms or 3.7oz to sit in the nose. And that means you can go with the ESC and battery pack in the nose behind the motor and go for a little more pack capacity if you need any extra nose weight. There's no information on the prop sizes either from HK or user reviews yet but with a Kv value of 1050 it suggests that props in the 11 to 12 inch range would be suitable.

To me this suggests a better option.

RDJeff

My Feedback: (11)

I do like the looks of the specs on that motor over what I found. I guess I wasn't thorough enough in my digging. Thanks for saving me some trouble and steering me to a better choice!