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View Full Version : Help needed with set up for 1/8th scale hydroplane mhr 8255



racerr73
07-12-2017, 03:10 AM
152552152553152554152555152556Hi Guys,
I have an electric powered ML Boatworks 8255 1/8th scale hydroplane powered by a TP 4070 880kv motor on 10s1p lipos and am having handling problems with this hull. The driveline is offset to the right ¼ of an inch looking from the back and the rudder (sport 40 square rudder) has been tried both on the right side of the hull and now the left side. Driveline was offset due to turn fin and rudder being on same side of boat. I have used 447/3, x450/2, x452/2 props without any success. The boat now has a ½ inch by ½ inch airdam under the hull. Strut is a flat bottom and set 26mm below bottom of hull and flat (no negative or positive).
The problem is the boat is very unsettled and basically flighty even in smooth water conditions. IF you drive it flat out it will blow over down the straight away, even with the batteries as far forward as possible , however if it hits another boats wash and gets airborne it always lands front first which is telling me there is too much weight forward but I need the weight there as it blows over down the straight.
Questions:
Where should the C of G be for this hull?
How do you get the hull to sit level left to right sponson wise with 10s packs jammed 1.5 inches off centre to the right due to the tub offset?
Rudder best on left or right?
Strut depth ?
Is there anyone racing these successfully in electric form?

All help will be greatly appreciated.

Thanks
Trev

Peter A
07-12-2017, 04:15 PM
I do not have one of these hulls, but I have an 8255 moulded hull that is 10% smaller as it was originally designed as a sport 45 setup. I run mine as a Q sport hydro and have a TP 4060 1620 kv on 6s1P turning a prather 230. I find that if the strut is too high then it gets a lot of air under it even with an air dam, also as I am not constrained by rules on this my strut is mounted on the transom.
You can try dropping the strut further until it settles down, even the other day my boat was running quite flighty and an adjustment of around 1mm settled it down nicely. Speed wise it is around the 110 + kph and with good driving can hold it's own against petrol sport hydros and a 90 twin rigger. CG is through the center of the turn fin which the placement is pretty much the same as yours. You could try a prop with some more lift, or perhaps prather 235, 240.
The offset weight is not a problem for racing ovals and my prop is offset further than yours, I would have to measure it but I think it was around 3/4". I run my rudder on the right, but that is just my preference.
All I can suggest you can try here is strut adjustments and prop changes untill you find the sweet spot. Sorry if I cannot be any more help than that.

racerr73
07-12-2017, 08:48 PM
Hi Peter A,

Thanks for your reply , I will play around with different strut settings and props.

Thanks

Trev