Sport 40 conversion to FE

[68Bud]

The OS 46 in the Atlas was starting to get pretty worn so I thought it was time for some new power. Here is the T600 1400kv and custom mount I fabricated today. Set up will be 4S, 120A ESC, and a 45mm prop. Tips and suggestions welcome.

 

[Jim Caldwell]

Make sure the balance point will be the same with the battery's and speed control are in there!

That is a 6s motor and the speed control is small, 180 to 240 usually required.

 

[68Bud]

Thanks Jim, I am still learning FE and based my setup on advice I received here http://www.rumrunnerracing.com/feforums/showthread.php?t=31771 Is the 120A ESC http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8946 too small for sport running on 4S? What prop would you recommend on 6S?

 

[carlnoki]

Those motors LOVE 6S

I know, I run them in my Twin mono.

Run at least a 180Amp ESC using 6S or even 4S for that matter.

on 4S start with an 445. watch the temps on the motor and esc. (but on 4S it possibly won't get up on plane)

The twin is the pic in my avatar

 

[68Bud]

Thanks Carl, I appreciate your advice. I am going to try the 4S 120A ESC setup and see what kind of temps I get. If the ESC runs too hot I will upgrade to the 180A per both you and Mr. Caldwell's suggestions.

If you could, please explain why a 1400kv outrunner on 6S at 30,000 rpm is better than using a water cooled inrunner at the same rpm? It was my understanding outrunners are more efficient and powerful at lower rpm.

 

[68Bud]

Testing update.

During the initial test the T600, 120A ESC, 45 mm prop combo performed well on 4s and the motor temps were only in the 80's. Speeds were acceptable but I was looking for more. Follow up testing was with a 47 mm prop and more motor timing. Motor temps increased slightly into the mid 90's on 5-6 lap runs and the ESC temps never got above 80*F. Speeds improved substantially and are near the limits of the Dumas hull. With the CG 1" behind the sponson transoms and the strut set slightly negative at 7/8" the boat is carrying the left sponson in the straights with some kiting. The only bad habit the boat has is the right sponson sucks down hard at anything less than 3/4 throttle. I have played with the turn fin shape and angle but have yet to solve the problem. I'm curious if this is an effect of torque roll or the poor geometry of the narrow Dumas hull?

 

[carlnoki]

those hulls were originally designed to be run in the NAMBA Sport 40 1 class using the side exhaust port motors way back when.

you might try a x-642 on the boat. but watch the amp draw on the ESC.

 

[jayt]

you might try a x-642 on the boat. but watch the amp draw on the ESC.

A 42mm prop will probably not have a large enough thrust cone to move the boat efficiently. The x447 has been very popular with similar hydros and suits the motor pretty well.

The sucking down of the right sponson could be caused by running the strut too high....or too low. Try changing the strut depth in 1/8" increments each way and see if it gets any better. Worked for a club member recently.....

.

 

[68Bud]

Thanks for the replies. I appreciate the advice. I will try adjusting the strut to correct the sponson diving issue.

 

[BACKEMF]

If you were to run 5s2p with that motor you can turn a D/T 450 for 6 laps plus mill. It'll do about 55 maybe more with tuning. It will come on plane faster with a larger prop.

 

[68Bud]

Thanks Ray. The 5s / 50 mm prop setup could be interesting.