Cobra FE Tunnel Hull Build

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Mike Luszcz

Well-Known Member
Vendor
Joined
Jul 31, 2008
Messages
4,176
Well, I finally got some time to work on this boat today. Its one of Dan Hutchensons Cobra tunnels done up in FE. The boat will use the OS lower, Medusa 36-60-2000kv motor, and Hydra 120 ESC, and Hitec 645mg steering servo, with of course, 4 cell Zippy Flightmax pack!. So far so good, Mike

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nice job on the radio box. wow super looking very impressive. i cant wait to find out how it handles
 
Dan,

Two questions:

1. What speeds have people gotten out of this hull?

2. Do they require the extended lower unit (OS/Lawless) or can you run the shorter K&B style lower?

Thanks
 
i not sure about a exact speed but i would guess high 50s. john otto has one of the fastest mod tunnels around here . and he ran this hull at the tunnel chanps finished 1st place. everyone here runs the os/lawless. only because they dont break shafts as easly. but i dont see a problem with the k&b lower . as long as you get one of the extended motor mounts from technology hobbies. if you want one let me know ill be seeing john soon i think there 25.00
 
Well, I got he boat finished today, just a couple minor things to finalize, but I got it to the pond. This boat is fast! Out of the gate, its faster than my VS1 was. The only real difference was the VS1 had a 2030kv UL-1 motor, and the Cobra is running a 36-60-2000kv motor. I think torque is going to be the advantage with the medusa, but I am running the prop that was on my VS1, the 42x55 grim prop. The boat has some see-saw right now, and my steering EPA was a little high, but the boat had a great attack angle and was handling the heavy winds we had today. I got home and put a straight edge on the sponsons..They are going to need some work, there is an obvious curve on the ride pad, so I will have to get that flattened out. I think that is the cause of the high speed seesaw I was experiencing today. The boat runs very light on its heals and if I had to guess I would say it weights the same or maybe a little less than the rigged VS1. I heard someone saying "the heavier they are the harder they fall" on another forum talking about the VS1 versus other boats, well, I don't think that is true, I think the Cobra, and the Vision for that matter, when set up, might just kill the VS1 in FE form. So far, I like it! I have some tuning to do, but I just wanted to get it on the water, and see how it was to start with. Once blueprinted, and motor angle are adjusted, its gonna be fast. I also think I am way underproped as the motor and hydra 120 were ice cold when I brought them back in, so I may be moving up to a larger prop once the boat is set to handle more speed. Here are some final pics of the boat, Mike

Oh, btw, I have been using the REK lowers since the start of my FE days, and I must say, I like the OS lower 10 fold over the old k&B and REK lowers. The ability to adjust it without messing up the steering cables is GREAT!

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Do you feel the ride pad is suppose to stay like that, cause the sniper I bought used had all of that curve removed to a totally straight ride pad. Let me know, Mike
 
I am going to say the hook is supposed to be there, but SHHHH keep it quiet ;)

PM Bill about it to make sure
 
Well, a hook I could understand, but this is reverse of a hook, its high at the stern, then comes down a 1/16" at about 2" from the stern, then rides smooth from there forward. I know it rides a lot like my wof project did, and it makes it hard to stay at full speed with the hop!
 
This hull looks very similar to some other hard to get 3.5 tunnels i have seen in the past lol yet still very impressive

but the question is how hard are these to get your hands on?

are they good to go and can be shipped tomorrow or are they holding off on production so that a few boys can destroy there competition

just a sport boater and want to run fast with a FE. my gas and nitro boats are at home. cant get fuel where i live!!!

i now have 2 cheap FE boats and really have a hunger for tunnels and speed. i would alter from this setup throw. same hull with a lawless and a nue motor 4s 2p just to make the wire config under the cowl. just looks a little messy for me. but you can get car brushless engines that have the wires come from the shaft end. could be neater.

the reason as to why i need short wires and a tidy set up is that the water here is 27-30 degrees c all year. water cooling just doesn't cut it i wish i could run my setups on water that's 10 or 15 degrees c

forget the hydra get yourself a B-X200A /42v

google it 200amp esc from china good quality and aircooled x3 50mm fans esc 130 mm long the last fan will cover the caps
 
Ok, read your post again, do you even know what you are talking about? 4s2p??? Where do you plan to fit that much battery? And why would I use an air cooled esc? There is no room, and frankly why would I want to keep the heat in a sealed radio box? On the positive note, you can get the hull easily from Dan Hutchinsen here in intlwaters, and there is no wait time. Next, why put a lawless on it, it was designed for use with the OS, and frankly, the OS has got to be the nicest lower I have used, and I have a lawless and rek, and this is so much better. Next, sorry my wires look "messy", but it is what it is and I don't care to spend an extra $120 to get a neu motor to hide wires. In fact neu's wiring is just like this motor. The medusa gives this boat all the power it needs, and for that matter so does the hydra 120. I don't know what brand controller you are talking about, but a 200a controller would not even fit in a hull this size. I use hobbywing controllers most of the time, and just recently got some hydra controllers and have no problems with them. Good luck with your build, with that kind of wishlist in a 29" hull your gonna need it. I am just a sport boater too, and this setup gives me everything I need. Mike
 
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So your saying it has a 'rocker' (meaning when you put it on a flat board it rocks back and forth like a see-saw? If so that is bad...
 
The boat looks good. Let us know how it does when it is dialed in.

As far as using a Neu Motor and 4s2p, that takes a bigger boat than this one. you will never even come close to keeping that thing on the water.
 
Looking good.

I've stuffed 4S2P into a 30 inch boat before. Not only does it turn out too heavy to run well. It also ate the small cables nearly as fast as I could change them out.

I've got a Leecraft XT460 that I run with a several large 4S motors and it's almost too small.

Looking forward to my cobra, it'll be on the way soon. Maybe I'll get it done in time for the LA SAWs.
 
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