Discussion
I am currently building a 1:12 Riva Aquarama from a short kit (formers and a not very detailed plan)
https://www.sarikhobbies.com/product/riva-aquarama...
I have rudders and prop shafts on order, and a lot of building in the meantime...
Can anyone recommend (brush less) motors and prop sizes to use?
Model is approx 870mm long, and will be reasonably heavy...
Twin drive
I can physically fit 30-40 mm size props
Plan suggests 400 size motors,but not sure exactly how this translates to brush less.
Would running contrarotating props offer any benefit?
Do I need to water cool them?
I quite like cheap Chinese stuff!
I have lipos and 6 channel radio gear, but not sure if the radio gear is clever enough to do proportional power depending on the rudder, or if I would want to!
Also, anyone have any recommendations for deck hardware? Amati make a similar sized model, but it is expensive.
https://www.sarikhobbies.com/product/riva-aquarama...
I have rudders and prop shafts on order, and a lot of building in the meantime...
Can anyone recommend (brush less) motors and prop sizes to use?
Model is approx 870mm long, and will be reasonably heavy...
Twin drive
I can physically fit 30-40 mm size props
Plan suggests 400 size motors,but not sure exactly how this translates to brush less.
Would running contrarotating props offer any benefit?
Do I need to water cool them?
I quite like cheap Chinese stuff!
I have lipos and 6 channel radio gear, but not sure if the radio gear is clever enough to do proportional power depending on the rudder, or if I would want to!
Also, anyone have any recommendations for deck hardware? Amati make a similar sized model, but it is expensive.
I'm relatively new to RC boats, but I've built a few in the past year.
The first model I bought was a Riva Aquarama, a bit smaller than yours at around 650mm. I bought it from a club member who was thinning his collection, so I have no idea what kit he used. I've re-jigged the running gear a bit.
It's fitted with two 2830 1000kv brushless motors, badged as Mtronik, but actually made by Turnigy I believe. Two Mtronik 15A ESCs, and 30mm props (left and right handed). Powered by a pair of 3s 2200mAH LiPos.
It gets up on the plane nicely, plenty fast enough.
I think I'd be fitting something a bit bigger in your boat, maybe 3542. Stick with 1000kv if you are going to use 3s packs, or 1400/1600kv if you are going to use 2s.
I use a Futaba T7C transmitter, which is quite an old 2.4GHz set, but has some mixing options. I've set it up to mix the 2 motors onto one stick channel, and to add a bit of the "outside" motor with the rudder. Probably doesn't help much at higher speeds, but is really useful for low-speed turning.
One modification that I really should get around to is fitting spray rails, running from high up on the bow down to the water line about half way along. The hull design creates a huge bow wave, which breaks over the windscreen and into the cockpit just as it starts to plane. From what I've seen, the addition of spray rails stops this.
I get most of my electrics from HobbyKing, normally Turnigy or their own branded stuff. Never had a problem with it.
Oh, I've never bothered with watercooling brushless motors. Not really necessary unless you are building something stupidly fast. Motors in my boats get barely warm, even after a 30 minute session.
Tricky to watercool an outrunner motor (unless you use a watercooled mount), so you'd have to use inrunners, and they tend to rev too fast for scale boats.
The first model I bought was a Riva Aquarama, a bit smaller than yours at around 650mm. I bought it from a club member who was thinning his collection, so I have no idea what kit he used. I've re-jigged the running gear a bit.
It's fitted with two 2830 1000kv brushless motors, badged as Mtronik, but actually made by Turnigy I believe. Two Mtronik 15A ESCs, and 30mm props (left and right handed). Powered by a pair of 3s 2200mAH LiPos.
It gets up on the plane nicely, plenty fast enough.
I think I'd be fitting something a bit bigger in your boat, maybe 3542. Stick with 1000kv if you are going to use 3s packs, or 1400/1600kv if you are going to use 2s.
I use a Futaba T7C transmitter, which is quite an old 2.4GHz set, but has some mixing options. I've set it up to mix the 2 motors onto one stick channel, and to add a bit of the "outside" motor with the rudder. Probably doesn't help much at higher speeds, but is really useful for low-speed turning.
One modification that I really should get around to is fitting spray rails, running from high up on the bow down to the water line about half way along. The hull design creates a huge bow wave, which breaks over the windscreen and into the cockpit just as it starts to plane. From what I've seen, the addition of spray rails stops this.
I get most of my electrics from HobbyKing, normally Turnigy or their own branded stuff. Never had a problem with it.
Oh, I've never bothered with watercooling brushless motors. Not really necessary unless you are building something stupidly fast. Motors in my boats get barely warm, even after a 30 minute session.
Tricky to watercool an outrunner motor (unless you use a watercooled mount), so you'd have to use inrunners, and they tend to rev too fast for scale boats.
Edited by clockworks on Thursday 13th August 18:31
Edited by clockworks on Thursday 13th August 18:36
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