Joysway seadrifter driving me flipping nuts

[flipper]

Hi all,

I am hoping you guys can point me in the direction of some trimming tips that can save my rescue boat some work. I have a Joysway Seadrifter and the problem is it doesn't like to stay in/on the water, it enjoys a good flip, and seldom lands right side up.

I have attached some pics of the boat and a video of it on top form.

Please try and resist suggestions like, get a bigger boat, calmer lake, etc. cos I wont be beaten/can't. Although if physics insists what can you do !

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[flipper]

Final pic of the offenders bottom

55800

[Stinger9D9]

I'm by no means an expert, but I'd try lowering the depth of the strut. That should raise the transom of the boat a bit - and lower the front - so not as much air gets under the hull.

[Peregrine]

It doesn't look like it is blowing over, it looks to me like it is a torque spin. Is it happening under acceleration? Looks like it needs more side to side stability. So, maybe the strut lower will be a good start place, if not, how about trim tabs?

[flipper]

It happens equally when turning and when flat out, and not as often, when accelerating, despite my videos evidence. Edit... On second thoughts it maybe is related to changes of throttle, I would have to wait till my next outing to be sure, but re-watching the video I can see how it would bring that conclusion.

Apologies for the newbieness, the strut being part of the bracket that adjusts the ride height of the prop ? Assuming yes, do I always keep the thrust angle of the prop parallel to the large flat section of the hull (the part between what I would call the side rails) ?

Trim tabs, no problem, try the strut 1st though ? Then tabs for lateral stability ? Assuming it is torque do I just put one trim tab on ?

[Rumdog]

No trim tabs on a hydro. You are correct on the strut. Lower it a bit. If still a no go give the prop a little negative thrust. Meaning you want it thrusting downward a degree or two. You'll also want a turn fin on that boat. It mounts on the rear of the starboard sponson.

[flipper]

Negative thrust giving the effect of lifting the rear, sinking the front ?

Can do a turn fin to, is putting it on the right a standard ? (I guess for a clockwise, right hand turn course). I'm just messing about with it so it gets left and right turns just as frequently. Does the weakened ability to turn left outweigh a turn fins stability advantages ?

[Rumdog]

No way. You'll be VERY pleased with the ability to rip a wide oper hairpin turn to the right. It will prob. help straight line stability as well.

Neg. thrust will help keep the sponsons planted a bit. Where is your CG?

[flipper]

A fin like this one ?

http://www.ebay.co.uk/itm/TURN-FINS-SMALL-rc-model-boat-turnfin-nitro-electric-/150540753493?pt=UK_ToysGames_RadioControlled_JN&hash=item230ced9a55

With a bend in it like mentioned here ? Or just set at an angle ?

http://www.fastelectrics.net/hydroplanes.php#turn_fin_shapes

COG pic attached, measured with the top deck on, photographed with it off. Battery as far forward as it goes.

55802

[Rumdog]

Those are mono fins. You need one like this: http://www.offshoreelectrics.com/proddetail.php?prod=dh-aqub9515

[flipper]

I thought as much, being in the UK we don't have as many sources. Just wondered if they would be passable. I shall search more.

EDIT, this sort o thing http://www.astecmodels.co.uk/catalog/product_info.php?cPath=1_36&products_id=745

[Rumdog]

OSE sells to the U.K. Right?

[flipper]

No doubt, should of explained myself, didn't want to wait for the Airmail :)

[Stinger9D9]

Here's the reason you don't want trim tabs. If the boat is running properly, the transom (rear of the boat) will not even be touching the water. The prop lifts the rear end and the centerline of the prop runs on the surface.

55814

[flipper]

Turn fin ordered, will adjust the strut on next outing to and report back. Thanks for all the help.

Cam.

[sundog]

I have an easier fix. Looks like torque roll to me - hydro's are very susceptible to this effect. As soon as it leaves the water for whatever reason it will roll over quickly. Try stuffing half your battery (or more) into the left sponson and see if that alleviates the problem.

[flipper]

OK, I have obtained the fin from Astec models as per my above link. Question, where about on the rear of the starboard sponson do I put it ? Vertically, as low as possible ? Horizontally, close to the center or on the extreme edge of the sponson ?

Cheers, Cam.

[pukpquango]

apologies for thread necro.... I have access to one of these tricky beasts..... Did the OP get any joy sorting the handling of this hydro ?

[flipper]

Nothing wrong with a bit thread necro :)

I am embarrassed to say.... I still have the boat, I made the mods suggested above (turn fin, and shifting the battery) but I haven't yet tried it with the mods. Life got in the way, got married, moved house, etc.. That and I got it's big brother which is very nice. Maybe this summer, given it's ability to flip it doesn't get run in the winter because I don't like going for a dip to retrieve it in freezing water.

Meanwhile I would suggest only using it on days when there isn't a ripple on the pond, it's far far move forgiving then.

[pukpquango]

all understandable. Be interested to see what happens when you do. I'm currently running a 100% success rate for flipping it, the twitchy little XXXX but the flips are getting further and further apart.... Always next time. :smile: Thankfully no swimming required. Club membership and a park pond means merely taking ones turn in the waders when others are in need :smile:

[flipper]

Haha, yes I also have to experience a trip out without flipping it. I was tempted to sell it but didn't because it is such an endearing and naughty little beggar. Boy does it go for it's size.

I will keep you updated, I really do hope the mods work as despite it's flipping ability I would hate to see it go !

[pukpquango]

Adding to the above.... Had this out for the first time in moths after a little fettling. Full disassembly and reassembly then gave the strut a tweak and got the desired result first time of asking. Didn't bother with a turn fin. The main problem now is going to be eliminating an irritating leak that managed to soak the radio, although no damage was done.
Still need to be careful when crossing wakes, but it has transformed the little monster. That weather has markedly improved can't have hurt either. No flipping or spinning and ran straight as a die from the word go. For a boat 17 inches long, is it ever quick.....An attention getter for the driver and a head turner at the club. Under rated I'd say.

Adjust the strut Flipper in small increments and see how the handling goes.

The only remote moment of worry was when turning into the wind and even then, miles better.

[flipper]

Wow good news, so all you have changed is the prop strut ? Angle or depth, or both ?

Cam.

[pukpquango]

Sorry for delay replying, I've been away from home for most of the last week.

Running the boat as supplied, I think the strut was right at the top of its travel depthwise, and more or less looked neutral in terms of angle. I took the approach of only adjusting one thing at a time, good whter it's a model car or boat - you make a change, test, make another change, wash rinse repeat as necessary..... I got lucky and seemed to hit a sweet spot with the first change - in this case shortening the strut. Visually the ride is now such the at speed the transom is clear of the water as is the all but the rear most portion of teh sponsons. More less no change in angle was required. I guess like all mass produced models, it depends on who bolted it together and how much care they took.

Whoever bolted this one together just parked it with the strut fully extended. One tweak and seems happy. I'll get one of the club camera buffs to snap it at speed and assess whether any further adjustment is needed.

[flipper]

Understood and thanks again for the reply. If you get a chance a side on photo of the back end would be nice, like the 4th photo in my original post. Would help me compare things.

Cam.

[pukpquango]

Understood and thanks again for the reply. If you get a chance a side on photo of the back end would be nice, like the 4th photo in my original post. Would help me compare things.

Cam. Will endeavour to so. At the moment, the problems are .....

Bad build quality. The hull is cracking around the cooling water outlet, which appears to have been drilled with the bluntest drill in the factory by a worker with the skill of an orang utan. I prophesy an appointment with some epoxy and glass cloth in this hulls future. This is where the water was coming from.

Bad electronics. But not the speed controller which works just as well or badly as it ever did. Either the transmitter or the receiver has given up the ghost in a very pecuiiar way. Receiver powers up and binds, but no tone from the ESC and no servo control. Put a different radio reciever in the boat and everything works fine with the corresponding transmitter.

[flipper]

I actually shifted the water outlet on mine. The original position points it straight back into the water which I never like because you can't really see the water stream while the boat is running so you don't know if it's blocked etc.

Can't comment on the electronics, none of mine are original, actually come to think of it I suspect my original ESC packed up.

Cam.

[bayareaheli]

Nothing wrong with a bit thread necro :)

I am embarrassed to say.... I still have the boat, I made the mods suggested above (turn fin, and shifting the battery) but I haven't yet tried it with the mods. Life got in the way, got married, moved house, etc.. That and I got it's big brother which is very nice. Maybe this summer, given it's ability to flip it doesn't get run in the winter because I don't like going for a dip to retrieve it in freezing water.

Meanwhile I would suggest only using it on days when there isn't a ripple on the pond, it's far far move forgiving then.

smaller prop will help out alot go down one size will help with the torque rolls :)