mocars2

Gerald - is that the same stuffing tube and shaft you used with the flex connector? If so how long is each? And what happened when you replaced the 2"+ flex - did you move the motor or is the prop now closer to the hull? Who's and where did you get that shaft and tube from?
looking good so far. Let's see a pic of the prop and rudder again now without the flex coupler.

Wheelnut

My Feedback: (81)

Yes it is the same one. The stuffing tube is 5.5" and the shaft is 9.5". When I replaced the flex coupler with the straight coupler I installed a new motor mount so that the prop would be in the same position. The first mount I installed is still there because it was too hard to get out.

drive2survive

My Feedback: (27)

just seen you guyz are wanting to hop up some boats, had real good results with a mega/3 on a 3s 2000 lipo, was at 1/2 throttle halfway down a striaght away and went WOT, it actually torqued out of the water and I had to throttle back then WOT again and it settled down , but keep in mind this was a on a small outboard tunnel hull, so Im real anxious to go inboard and see what happens.........only problem is gotta geta bigger ESC , but yes BL/lipo is the only way to go

Wheelnut

My Feedback: (81)

Ok, I'm at the end of my rope. Here is some videos of the problem that won't go away. The boat is now converted to the straight coupler so I don't experience anymore broke flex couplers. I am running two 6 cell packs. On the video named Kyosho Run 2 the batteries were moved forward about 3"s and on the video named Kyosho Run 3 they were moved as far forward as possible. The only thing I can think of now is to add trim tabs. Does anyone think that will help or have anyother ideas other than going back to subsurface drive.

http://www.rcuvideos.com/view_video....3b1abaebd2faed

http://www.rcuvideos.com/view_video....ec9a21b9ac34ff

http://www.rcuvideos.com/view_video....23cc7352950e88

CadillacDTS2001

i think you have sucefully hit the maximum hull speed !befor it becomes undriveable !!!
u could try a new ride pad on the stern and some trim tabs , that might help , and if it doesnt , well the boat wasnt suposed to go that fast !

Wheelnut

My Feedback: (81)

Thanks eyekandy, thats exactly what I was thinking. I am going to try the trim tabs first as that will be the easiest first step. Then if that doesn't work I will try the ride pad, I will definetly need some help with that. I should be able to get the trim tabs on with video by tomorrow.[sm=49_49.gif]

Wheelnut

My Feedback: (81)

Got the trim Tabs on, they are kyosho adjustable trim tabs. And I put the batteries as far forward as possible. Well the problem was a little different this time. It was still jumping out of the water but not as bad, it was kindof almost wanting to do a nose dive. The big problem is that the boat flipped. I had to rescue it with my Zig Zag. I had the hatch taped good but I was stupid and forgot to remove the old body post that holds the hatch down and water was getting in through there. By the time I got the boat in it was almost full of water. All electronics are ok, I won't make that mistake again. I am taking off the body post today. I would have a video for you but my son forgot to press the record button. Sorry, he's only 6. anyway. I think Two adjustments may help alot. I will move the batteries back a little and adjust the trimtabs a little more and I am going to reduce the prop size a couple of mm's. No more time today. I have to go to class. I will try this probalby tomorrow, weather permitting.

jdoug

grk65 - This looks like the same problem as the Gecko has. It reaches a certain speed and wants to come out of the water. I think if you were able to adjust the drive to have 0 deg. thrust angle...it would help. I've considered doing this on my Gecko. Instead of the stuff tube coming out at a slightly neg. thrust angle, I would remove it and put it back in at 0 degrees to the bottom of the V. So the faster the motor turns the more forward only push you'll get. With having the thrust angle slightly negative (trimmed down), I think the prop is pushing the boat up and out of the water when pushed beyond a certain speed. If the thrust angle was 0 deg., I think the boat would just be pushed forward and not up at the angle of the prop shaft.

Now keep in mind: all this is assumption and me trying to figure out why the Gecko starts hopping beyond a certain speed on flat calm water. Does it make sense?

Wheelnut

My Feedback: (81)

I believe it does make sense. That means I will have to go back to a flex connector. The problem is that the graupner flex connector that I bought form offshore won't handle the power of a brushless. Steve said he didnt know if it would handle it or not and I guess I proved it wouldn't. So I need to find a better 1/8" to 3/16" flex connector. Any ideas on that? Or maybe I need to go with a flex cable drive. ???

jdoug

Well...in order to get the prop shaft at 0 deg. out the back, then you would have to go with a flex cable and strut. Or, re-install the aluminum stuff tube at 0 deg. but you would have to run a flex cable.

ryan_t888

grk,

Do you any pics of the rear end with the camera in line with the bottom of the hull?

My buddies old v hull jumped around a lot cause the prop shaft exited the hull too high. After re-aligning the shaft lower in the bottom of the v and having the prop shaft at 0 degrees it still bounced. I told him to get the prop deeper in the water by angling it down and it no longer bounced.

Also, my tunnel will bounce a lot(not to your extent) if the prop is too shallow in the water.

Just a thought, Good Luck
Ryan

Wheelnut

My Feedback: (81)

Thanks Ryan, here are some pics of what you were asking for. But, I think I just found the problem. Notice on the pic where I have tilted up the boat so you can see the contour of the bottom of the boat. Notice that it really doesn't have a flat spot. It may be hard to see in the picture, but its kind of like a u shape. The rear is a little more flat, but there is a point where the bottom is at its lowest several inches infront of where the prop comes out, and it curves up from there towards the front and towards the rear. This curve is even more apparent in the picture showing where the alignment of the prop comes out of the rear. Meaning it can't really plane out. The boat will always be jumping out of the water, no matter what the angle of the prop. Just some angles are worse than others. I think eyekandy's idea to put down some ride pads. Honestly I am a little tired of this boat and if I don't get it right before my Supervee gets here, which has already shipped by the way, then I may not mess with this boat for quite a while. lol I will probably make the ride pads over the winter. Any ideas on that would be greatly appreciated. Or any other ideas.

jdoug

grk - I think you found it. I saw the last pic and thought the same thing. Unless you can get the boat to plane out on the last 3 in. with the nose way up in the air...then it will bounce.

Wheelnut

My Feedback: (81)

well, I have also thought of the fact that it will be pretty difficult to make ride pads for a curved boat that will be flat enough for it to ride nice. Not to mention that would be alot of work not knowing the results.
I am going to give her a proper lake burial.[sm=cry_smile.gif] This will be on video.

ryan_t888

LOL, what is the BL system gonna be put into?

Ryan

CadillacDTS2001

yaaaaa ur gona sink it !

Wheelnut

My Feedback: (81)

I haven't figured out what the brushless system will go in yet, but I am looking to get a Hammer EP hull cheap and I want to try the same thing with it. So if anyone knows where I can get a Hammer EP hull cheap, I'm all ears

Yep, proper buriel scheduled soon. Kyosho will be going [sm=drowning.gif]

I am still waiting t hear back from Hellomynameisdookie to see how his surface drive conversion went on his Hammer. He said ran great, but all the details were on another page that got deleted that time RCU had some hicups and alot of stuff got deleted. I even lost whole thread.

mocars2

GRK - so that's what happened to the hammer conversion thread - I thought I'd seen one - I'd also love to see it and all the pics. I have a stinger SS and via the other thread on the comparision - they look very much alike.

AWDEVO8

What a great thread. The videos are really cool! Props to your 6 yr old! I have an idea for you though. What about using A Jet-Stream 800 hull? Its nice and long and has a big flat spot for ya! I wish I still had mine...I sold it for 40 bucks! Id send it to ya for free to see how fast it would be![X(]

Andrewg

You need to do a bit of work before the trim tabs

trim tabs will hide the problem not fix it


first set the balance point on the hull so it is at 28% of the hull length, as measured from the transom - at the moment it looks like you have the weight and balance poitn to far rearward this will make the hull porpoise (the name for what it is doing)

Whats also happening is the hull is flexing and/or the water is following the contour of the rounded transom and this causes drag at the rear of the hull which pushes the nose down then when it releases the boat shoots forward and up then it all happens again

Make sure the hull running surfaces are stiff - and i mean stiff as a rock and the trailing edge at the transom is square and sharp - knife edge sharp - make the hulls tiff with balsa reinforcing ca'd or epoxied in make the dges sharp by damming it along the edge using a bit of tape and lett the ca dry - then sand it sharp - this gives you a hard shap edge

With the weight in the right place the hull will run flat, withthe hull stif and sharp drag will be reduced and the water will break awya from it easily and it will run much flatter - then if you can stop the popoising by moving the balance poitn around, use the tabs - tabs are a source of drag and a last resort option

Wheelnut

My Feedback: (81)

Thanks AWDEVO8, Thanks for the tip on the Jetstream 800 I would like to see the hull as I have never seen one. I am currently looking for a Hammer EP hull. I am also waiting on Hellomynameisdookie to help us out here on his lost thread.

Andrewg, thanks for all the helpfull information but with my new Supervee coming, I am not willing to spend that much more time on this hull. I am hoping to find a hull that is almost ready for this type of setup, as you see I am thinking about the hammer or someother boat. I have had it with the Sunstorm.

Thanks to everyone. I will have the lake buriel video soon.

Andrewg

If you want a nice fast hull for that motor could I suggest a cambel shovel on hull on 8 cells or a H&M No Step 2 on 8 cells you will have agreat handlign baot -s tay away from the hull which are not designed to race they handle poorly are poorly made and do not run fast in comparison to race hulls.

Stinger9d9

The Hammer would probably work really well for the conversion. The bottom of it is flat as a board for at least 12 inches ahead of the transom. I have an old GP Stinger SS, which I believe is the same hull (same company, same dimensions, just older).

It might be better if you get a hull from a Nitro Hammer, the fiberglass would probably take the beating from that ridiculously powerful BL motor you're using a little better than ABS.

Anyway, keep an eye out for a GP Stinger as well in your search if you want to go ABS. One just went for about $60 on Ebay with a radio.

I tried to email hellomynameisdookie about his thread, and the email just bounced back, so I think we are out of luck. Too bad too, from what I read in the Hammer thread, he said it worked really well.

xism

AWDEVO8 good idea! yes thats a very nice hull i had almost never any "jumping out from the water" problems at all with my old jet stream like i have with my airstreak (hopeless). grk, small boats like sunstorm have the limits right there, i dont think its possible to get rid of them with change angle of trim planes, change props etc. if you wanna run faster - get a jet stream hull, and give it a chance

hellomynameisdookie

Hey guys, how's it going. Time to dig this one up from the grave!

Wheelnut, sorry I never got back to you. I've been out of the RC loop for...hell, probably almost 2 years now. Having a child can do that!

As to my Hammer: The Hammer kicks butt. I love it. For overall don't-worry-bout-nothin-just-go-and-sling-it-around-fun it's the one I run. The hull definately has it's limits and where mine is I believe is it. I've got it gps'd at 32mph on the Garmin with a 45k prop on 12 cells and an Offshore Electrics 700SC motor.

The only thing about it is that at mid-speed up it'll hook REAL bad if you're not super carefull on the steering. Once you get used to that it's not that big of a deal. Overall I wouldn't trade the conversion experience for anything. If I were to do it again I wouldn't use a Hammer hull but start with something more solid to begin with that was designed from the get-go to handle the extra power and speed.

Happy boating,

Bryan