First foray into Twins

[gil sonsino]

Hi Tyler have you tried the turnigy receiver relay? got two of them and they do not work with my Futaba Faast radio,is there any trick about them.Thanks in advance

Gill

 

[RaceMechaniX]

Hello Gil,

I have not tried them, but I did manage to paint the tub. I learned my pump runs best on 12V. 6V from the BEC was not enough. I bought a little 12A micro ESC and will use a small 3S lipo to power the pump. I will use a castle BEC to reduce the 3S lipo down to manageable servo power.

Tyler

 

[gil sonsino]

Thanks Tyler for the update.Well I decided to use a nano servo connected to a micro switch to activate my pump and it worked great but honestly I'm not satisfied with this extra setup as an electronic receiver switch would be easier...anyway it cooling down my esc's and motors! Gill

 

[Steven Bryant]

Nice build thread Tyler and really nice boat, will you be making the plans or kits available to buy? Would love to build one...

Sent from my iPhone using Tapatalk

 

[RaceMechaniX]

Hello Steven,

No plans on producing these as kits, first I have to see if I got the geometry right.

Tyler

 

[RaceMechaniX]

Update on the twin, finally got her in the water for the first time. Gotta say I am pretty happy with the first runs. I was targeting mid to upper 70's on 6S per motor and we got 78-80mph right off the bat. Current was a little high in the turns so we worked on the strut height and sponson inclination angle. It's great having data from both motors, but it makes for a lot of work comparing sides and overall numbers. RPM was between 24-28kRPM swinging some ABC props.

RTR she is a little over 22lbs.

 

[Danny King]

Nice!! I hadn’t seen this post or I didn’t remember seeing his post. Zzzzzzzzz

 

[DON MAHER]

Looking good, sure miss you guys!

 

[brad nichols]

Looks good!!

Brad

 

[RaceMechaniX]

We miss our CA Amigos too Don.

 

[Buckshot]

Killer!!

 

[Terry Keeley]

Sweet!

Looks very clean and well thought out. Would 6S be comparable to a .90 sized nitro motor?

Who made those strut brackets?

 

[RaceMechaniX]

Thx Terry,
The Q (6 cells) class is close to a 45 boat maybe a 67 depending on power system. A S (8 cells) or T (10 cells) is close to a 90 or strong gas motor.
I thought I would have to add two more cells with 8 total per motor to be competitive, but looks like 6S will work fine although the current is a little high. Not high for my standards, but still high.

The rear hardware is all Mark Grim. Very nice and stout designed for his gas riggers.


-Tyler

 

[Terry Keeley]

Thx Terry,
The Q (6 cells) class is close to a 45 boat maybe a 67 depending on power system. A S (8 cells) or T (10 cells) is close to a 90 or strong gas motor.
I thought I would have to add two more cells with 8 total per motor to be competitive, but looks like 6S will work fine although the current is a little high. Not high for my standards, but still high.

The rear hardware is all Mark Grim. Very nice and stout designed for his gas riggers.
View attachment 283799

-Tyler

Cool, thanks. Still trying to figure out the FE stuff, I guess amp draw (which relates to heat) is the limiting factor?

Mark makes some nice chit!

 

[RaceMechaniX]

Hey Terry, Generally yes heat is the limiter in most applications. There is a lot more diversity in electric motors compared to nitro. We have pole counts from 2-14, diameters from 20-100mm, lengths from 15-100mm+, Delta and Wye winding patterns and different winds to suit different voltages. And then you have to add in the speed controller where some combo's place nice together and others don't. Find a good combo like a green head and fat belly pipe and you are set. Other times you will chase your set-up indefinitely. Somewhere there is a happy balance of efficiency, heat rejection and power.

-Tyler

 

[RaceMechaniX]

Got some onboard video footage with the GoPro stuck on the nose of the Twin. Turn up the volume and hit the 4k option for maximum viewing pleasure.



Here is another run with smaller props.



And why not stick the camera on the front of the 35cc SGX rigger too. It was underpropped but look at Dougie Twaits Jr perfect launch technique.

 

[longballlumber]

Very Cool Tyler!

 

[Mark Bullard]

And remember what I said. The FE boats run on smoke. And when you let the smoke out. They quit working. And then it smells like money.

 

[Terry Keeley]

Awsome! Thanks for sharing!

 

[LohringMiller]

Is there a reason you didn't go with counter rotating props. I know the selection of RH props is more limited, but I would think canceling the torque effects would be worth it.

Lohring Miller