The Dauntless.

[785boats]

Thanks Doug.
It's good to get back to a bit of 'slow boat' building.

Here's a bit of work from yesterday.

Seat cushions for all three cockpits carved from balsa & painted to represent the tan leather. Just sitting loosely in place.
001.jpg

Fitted to the main bridge area.
004.jpg

The rear cockpit.
005.jpg

The front cockpit.
006.jpg

[bogieboy]

looking very nice!!!

[785boats]

Thankyou bogieboy.

Here's last nights effort.
I soldered up the frame for the canopy & covered it with some white linen.
I'm not sure about the rolled up sides. I don't know if the early version had them.
But later in its life there were some clear plastic sides that were rolled up when she was underway.

The frame.
001.jpg

The cover.
003.jpg

Another view.
004.jpg

[785boats]

The two prop shafts that I had been waiting for arrived the other day, so now there was a good reason the get the drive lines & rudder setup done. Then I can finish painting the hull.

The stuffing tubes had to be cut down & the end bearing popped out of the off cut & pressed into the shortened tube. Nice little flanged ball bearings they are too.
For the skegs I used some shortened 4mm struts with an extra bush pressed in on the prop side for extra longevity. The skegs were just recessed through the hull with a support blocks epoxied each side of them inside the hull.

Motor mounts were made from some 3mm aluminium angle.

The motors are a couple of Turnigy G32 770kv outrunners. They've been in the spare parts box for about 6 years. They should work well on 4s driving the 45mm 3 blade scale props.

The visuals.



I used a long shaft to get the mounts bent to the correct angle & to mark the center of the motors.
m_063.jpg

Before cutting the stuffing tubes down I used the full length with the shaft all the way back to the skeg to get the the mounts epoxied into the correct positions.
m_064.jpg

The finished installation complete with epoxy putty to support the end of the stuffing tube.
m_002.jpg

The basic rudder setup. Also shows the skegs & support blocks.
m_062.jpg

The underside.
m_065.jpg

[785boats]

Nearly finished now.

The hull sides & the deck are painted.
Made up some exhaust ports, the capstan winch, jack staff, & the davit for the tender, from bits & pieces of rod & tube etc..
Fitted everything in place, along with the anchor, and the chocks & cleats around the deck edges.
I've never liked the look of the exhausts on the original boat. They were too high up on the transom. So I've moved mine down to just above the waterline.
I think they look better.

Looks like I picked the wrong shade of blue. It should be darker
005.jpg

Chocks, cleats, jack staff added to the deck, & the exhaust ports in the transom.
011.jpg

The anchor & the capstan, chocks & cleats.
012.jpg

The davit for the tender. Need to make up a pulley & add some rope yet.
013.jpg

The maiden isn't far away now.

[jantagg]

On my boat I power with a single motor Turnigy T600 Outrunner for a 600 Heli (880kv), I bought from Hobby King. The ESC is a OSE 150amp.

[785boats]

That's interesting. Haven't seen a Dauntless with just a single motor.
What voltage do you use, & what size prop? I don't suppose you know the current draw by any chance do you?
I'm just trying to gauge what sort of power the hull needs to get up on the plane to a good scale speed.

[jantagg]

I'm using 2 2cell 5000mah lipo packs, in parallel That gives me plenty of run time.

[785boats]

Thanks for the info. But what size prop is she turning?

[785boats]

Just got back home from her sea trials.
Total success.
I initially ran it on 4s lipo but it was way too fast at full throttle. About fast scale cruising speed only took 1/5 of the throttle travel.
I ran the boat for about half an hour on 4s varying from full throttle to cruising to slow maneuvering, finishing with two laps at full throttle to get a gauge on the heat.
Both the motors & the ESC's were barely warm to the touch. No watercooling on anything, so I'm happy with that. Unfortunately the ameter I took to the lake wouldn't work, so no amp reading. I've got another one somewhere so I'll try that one tomorrow.
Both packs still had 68% & 64% capacity left in them.

So I changed down to 3s packs which is what is in the video.
Full throttle is still too fast but cruising speed is now about half throttle travel. Much more user friendly.
Still no temperature to speak of in the motors or ESC's.

Again, cruised around with slow speed & full speed for around half an hour
Packs were at 72% & 74% remaining.

The only disappointment is the whine of the motors. Never heard motors like that before. But I can live with it.

Here's a few pics from the lake, & a short video
The first little part is what I think is scale cruising speed, with a full throttle pass, out the back, at the end.

007.jpg

008.jpg

009.jpg

[785boats]

Had another little test run today, but it was rained out before I could try any timing changes. I wanted to try and reduce the noise of those motors.

The current draw is as follows.
On 4s lipo (14.8v),at full throttle, each motor pulls 29 amps. But the boat is way too fast for scale.
On 3s lipo (11.1V), at full throttle, each motor pulls 21amps. Total power 466 watts.
Still a bit too fast but much more manageable with throttle control.
At a fast scale speed ( about 3/4 throttle)the motors pull 18A each. Total power 400 watts.
Pretty economical for a 50" boat, I reckon.

Cheers.

[bhorowitz]

That's a beauty.

[vvviivvv]

I’m also refitting my large scale twin and trying to figure if I should water cool it or not... it’s a rare Hull and I don’t want to drill it,

Seeing your run times and temps gives me hope... it’s a 1.3m twin I’ll run on 2x 1521 1y and 3s lipo (because I have lying around) esc will be swordfish 220

Had thought about running 10k mah / side for long run times, it’s twin jets with plastic 35mm impellers....


I had thought up a internal cooling system using a gas fuel tank and mhz pump but might not need...

[785boats]

That's a beauty.

Thankyou. Scale boats were my first passion before I was bitten by the FE bug.

[785boats]

I’m also refitting my large scale twin and trying to figure if I should water cool it or not... it’s a rare Hull and I don’t want to drill it,

Seeing your run times and temps gives me hope... it’s a 1.3m twin I’ll run on 2x 1521 1y and 3s lipo (because I have lying around) esc will be swordfish 220

Had thought about running 10k mah / side for long run times, it’s twin jets with plastic 35mm impellers....


I had thought up a internal cooling system using a gas fuel tank and mhz pump but might not need...

A 35mm pump at only 17000 revs won't pull a lot of amps. Not enough to trouble those motors & ESC's without cooling. Heaps of headroom there.
But as with most scale boats we don't run flat out all the time. so cruising speed will be an even lower amp draw.
Just do what I did & hook up an amp meter for some readings on the load.

What boat are you working on?

The American enterprise that I'm also building has 3 26mm jet pumps with 1350kv outrunners on them ESC's will be 120A car type with a fan on them. No water cooling needed in this boat either. It's also a 50" long boat.

The three pumps & motors.
005.jpg