Vintage Dumas Hot Shot 3.5

[Adam Girard]

I picked this up over the holidays. I had a nitro boat when I was a teen, sold it on ebay mid teens, and recently got the itch to get another one. The boat/motor have never been used or rigged. The boat was built, and the engine is still new in box. I'm beginning to rig the boat and am looking for input on routing control cables/rods. I went to my lhs to get a radio/receiver, servos, gas tank, and battery pack. The boat came with a prather control cable kit. I've included a couple pictures. The control arm that came with the motor is a little different than others i've seen online, it mounts on either side of the motor vs the u shape with a place for a steering cable on each side of the motor. First question, is it ok to only have one steering rod, or is two preferred/required? is two only needed for larger motors.

 

[Adam Girard]

I have a 6 oz tank that i plan on putting in the rear compartment. The cowling/cover isn't pictured. The hole for the remote switch was already drilled so i used that location.

 

[Grimracer]

One rod.. NO ISSUE.. I used a 4-40 on mine

 

[Adam Girard]

thank you, 1 rod it is. I've got the ball joint already too.

The package came with a complete new vintage futaba 72 mhz 2 ch radio/servo set. i'm planning on upgrading to 2.4 ghz and new waterproof servos. is there any use for the futaba radio, or is it junk? I'm open to any and all advice on this boat build completion.

 

[Wasted wages]

What is the torque rating of your steering servo? Takes a lot of torque to swing an outboard....

72 mhz frequency radios are for R/C aircraft use. Not for surface use.

 

[Adam Girard]

Thanks for the info on the radio, I won't be using it. The servo that I currently have is 80 oz/in torque. Should I get the next step up, something over 100 oz/in? I bought the same size servo for both steering and throttle, but that seems a little overkill for the throttle.

 

[Adam Girard]

I got a spektrum tx/rx from the lhs, but my battery and servo connectors do not fit the housing of the rx. I need to go back later this week and get that straightened out.

 

[Wasted wages]

Different radio manufacturers use propitiatory
connections on their servo and battery plugs.
Some fit, but the pinouts on the wiring may be different from one manufacturer to another.
You have to be sure the wiring matches or
you can repin the plug if needed. Or cut and splice on a matching servo cord as a last resort. Use solder and heat shrink !!


I would think you probably need more than a
100 oz servo for the steering.. minimum of
150 oz I would put in the highest torque servo that fits the radio box, within your budget that has metal gears, and upgrade your power supply to the highest voltage allowed by the reciever and servo manufacturer for max torque.
Maybe someone that runs outboards can suggest a good servo starting point.

Keep your pushrods straight with no bends and use quality link ends.
You can also sleeve the 4-40 pushrod with a piece of tight fitting brass tubing soldered on both ends to stiffen the pushrod.

 

[Grimracer]

if you are going to run that motor on the boat. you only need about 50 oz in

Grim

 

[Marty Slater]

i got that kit sure wish i had the stickers to go on it

 

[Grimracer]

I have had a few and the gun decal must have been custom. I do remember it came with a water transfer "dumas" logo decal.. but thats it.

Grim

 

[Grimracer]

SS K+B.. updated bottom.. 45MPH and it would fly though the air like a Frisbee. LOL.. not a blow over mind you but a FRISBEE! LOL

 

[John Capps]

If you decide you want/need additional steering arms, I actually have 2 of them sitting in my box I'm not using. Will send them to you cheap.

 

[Jerry Dunlap]

SS K+B.. updated bottom.. 45MPH and it would fly though the air like a Frisbee. LOL.. not a blow over mind you but a FRISBEE! LOL

Was this picture taken in Don’s Hobby Shop?
JD

 

[Wasted wages]

if you are going to run that motor on the boat. you only need about 50 oz in

Grim

I wouldn't go that low....your talking about a servo like a S3003 or a S148...not real powerhouse servos...Heck I use more torque than that for third channel and throttle's...

I know way back when I got started in rc boats, the Hotshot was the first boat I ever built. I think it was almost a given to anyone starting in model boats to build a hotshot!

The hobby shop I purchased everything from suggested stepping up the steering servo and switching to ni cads as I was building it.

Maybe it's just me and my driving style, but steering is not anywhere I want to compromise on torque or reliability...
just my .02 !