41" Fantasm Build AKA "DARK MATTER"

[boddenboys4]

Well I did a 5s run on the balanced props and it ran great, but the stingers turned inward again and the inner bushings are lose in the stingers and the shafts have both pulled way back, time for the stinger upgrade.

[RCKong]

WOW... I use these and have not had this happen. Is it the hull or the stingers ? Do you use a flexshaft or two piece square drive in them ?
If you use a flexshaft, you gotta have a little space in between the drive dog and the stinger for the cable to spool up. Even though there is very little cable, it will still move in an 1/8" under load.

[boddenboys4]

I'm using the two piece square drive system. I left some play so that some movement is allowed. You think it may be the flex actually getting longer and forcing the solid part of the shaft back therefore pushing the inner bushing back? Should I pull the shaft into the collet more so it gives space for the square end to extend a little more and not bottom out on the solid shaft?

[RCKong]

no the cable will shorten as it winds up. I got rid of the square drive,I had some problems with them after they were used a few times. I bought Hughey 3/16 cables and replaced them. They work flawlessly and are very well balanced.

[boddenboys4]

Thanks I found them on Funrcboats.com. Out of stock at OFE. Should I go this way or get the drives that HOR has with the support brackets? They come with the shafts as well.

[RCKong]

do you have any pics of the stingers mounted on the transom after they twisted ? I saw the top veiw but I'm wanting to see what failed or where it twisted.

[Make-a-Wake]

On 8s that sucker is riding on the props!! Never seen a 1717 run on 8s..............big rpm's!! But, on the endbell the label says 45,000 rpms max which you are right at.

[RCKong]

Yea thats alot of torque on them stingers

[boddenboys4]

Its the bracket on top of the stingers that allows you to adjust the angle that have twisted a little, I will take a picture of it when I get the chance. The last run on 5s pulled them both in and the shafts back. But the props were balanced this time, it ran much better. Took on a 37" Genesis with a TP 4082-1200kv running on 10s and it had no trouble getting ahead.

[boddenboys4]

Well, I have changed the stingers, running a pair from HOR, first run on new 648s and a lot lost a blade off one prop, didn't hit anything just torque I guess. It's a bullet out of the hole. Couldn't get to see what its really got, weather wasn't too good. No GPS either, next time for sure. Awesome tumble but took it well, think it went over at about 70 mph. Will take pics and videos next run.

[ray schrauwen]

You run a heavy setup in that boat so you need those heavy duty Scale type stingers with the pod in the rear for support. I guess thats what you got from HOR...?

[boddenboys4]

Yeah that's the drives I'm running now, I've been running 648s from FC, what prop would you recommend for top speed?

[Fluid]

...I've been running 648s from FC, what prop would you recommend for top speed?

Before worrying about props, get your setup right. You can cut out several feet of wire between the ESC and the packs, do that first. Ditch the cheesy plugs and put on 6 to 8mm gold bullets. Shorten the motor wires - at that rpm you will get better ESC control of the motor by reducing inductance. Those changes will add speed and reliability while reducing heat and ripple current.



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[jcald2000]

2500KVA X 29 volts at 200 amp load on 6s 2p pack= 72,500 RPM.
But go with Jay's info, he has a lot of SAW experence.

[Fluid]

The Castle 1717 motors have a Kv of 1580, so on the water his 8S setup is closer to 41,000 rpm. The speed with x450 props on 8S should be around 80 mph, right were he was on the GPS. I'd use two-bladed counter-rotating props if it were me, and 3/16" cable - I think the OP is still using 0.150". Counter-rotating props require less rudder to hold the boat straight - less drag, higher speed.




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