Vision Tunnel P-Ltd OPC build for Ken Haines

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Darin Jordan

Well-Known Member
Joined
Mar 11, 2005
Messages
1,821
It's been almost a year since Ken sent this Vision tunnel home with me to build up for him, and I'm FINALLY getting around to getting it done for him. Had a couple of weeks working on it now. Figured I'd post some pictures.
 
Have the transom drilled/tapped for the lower unit. Ken gave it to me drilled up with pilot holes, so I just opened them up and tapped them for 8-32 screws.
 
I spent some time putting a lip around the inside to brace the cowl. I am NOT a big fan of this cowl arrangment and would much prefer a radio box with a standard removable cowl, but it is what it is. Should save a few ounces of weight I imagine. Has to be taped on, however, so I provided some interior support by epoxying on some carbon strips to provide the backing...
 
Custom fabbed up a servo mount, similiar to what I did for my Lynx. Trying to use as much composite and no wood for this one, so I use some carbon angle I made for the mounts, and made a mounting plate from G10. All of the stainless screws are directly tapped into the carbon, where I added doublers to increase the grip area. All secures nicely. Since this isn't something you take in and out and in an out, this arrangement holds up nicely.
 
Rigging is a 4-40 sized Dubro pull-pull kit. I use 60lb sized stainless fishing swivels through the threaded 4-40 sized clevis pins (through the threaded shaft section) rather than loop the cable through, as this holds up better and also provides a break-away point should the system fail in a flip/crash. Just replace the swivel head and you are back and running, as opposed to snapping the cable. Did this on my Lynx and it has been working exactly as designed. Blew over several times while attempting to set the 2-Lap record at the Nats last summer and was able to get back up and running in just a few minutes each time.
 
Made the transom plate at the back of the cowl using some carbon plate I laid up. Made a pattern using some tape and cutting it out with an Xacto knife. Cut and fitted the plate, and then set it in place with CA. Used a layer of Carbon fiber weave laid up on the inside of the cowl to secure this piece in place.
 
Wire exit ports are made from black fiberglass/carbon tubing. Wire extensions for the motor wires are held in place with heat shrink and tie-wraps, and stay part of the boat. This lets you remove the motor or ESC without having to reseal the transom.
 
Cable pass-troughs are sealed using a set of Pro Boat bellows from a BJ55. I ran them inside the boat, just to keep it cleaner looking, and CA'd them in place. Should provide a decent seal, especially after Ken has it painted/decaled up and puts some light grease in them.
 
Also, as you can see in the third picture here, I had to fab some spacers to raise the steering arm up to clear the transom. No biggy... some thick-walled aluminum and longer screws did the trick...
 
Now that the rigging is all set, I just need to glue in some water passthrough tubes for the ESC, and then install the radio and power system. Will hopefully have it ready for testing by Memorial Day weekend.
 
Finished up the build portion of this project... Basically just had to fit everything once the epoxy dried on the additions.
 
Boat weighs in at 5lbs 7oz RTR with 5000mAh Thunder Power 65C 4S1p pack. TONS of room for battery. You guys just go ahead and keep putting your steering servos at the back with those clunky solid rods... I'll keep mine up front, where it belongs, with an elegantly engineering pull-pull system, complete with breakaway swivels to help protect the cable. Ease of access and battery placement on this boat is a dream.
 
Still not completely fond of the tape-down hatch setup, but in practice, it was very easy to seal up. Definitely makes for a more open access to the internals.
 
A few more pics...
 
Also, I forgot to mention that I used 2-part expanding foam (2lb density) in the nose, and I also poured a narrow strip of foam down the center of the removable cowl section.
 
The foam in the nose was for floatation, obviously, but also to help solidify the nose. With the cowl being attached, if you hit a buoy or boat with the front of this, it's not going to breach and fill the insides with water.
 
Here is a video that my buddy, Theron, was nice enough to film for me during the testing sessions after the Puget Sound Model Boat Club NAMBA District 8 race on Saturday. The "dialing in" is coming along nicely. Have a few more tweaks to do to her, but overall, she's about ready to ship. Watch out, East Coast... Ken is going to be a force to be reconned with in this class!!

http://www.youtube.com/watch?feature=player_embedded&v=L6lPPDK9qPk
 
Darin, I figured once you got around to running the boat and realizing how much room there is for battery placement you would be a bit more fond of the cowl setup. my 1st vision tunnel was done that way until it was speared in a race. so naturally i did my second boat the same way. I am curious as to what you are finding is working for props?

the vision hull works great. I have found that I can run that hull flat out and not have to lift though the turns

top fuel ken is in ft pierce with the wave blasters club, the usually have a spring invitational fe race every year
 
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Darin,I like your setup with the fishing swivels ,do you still loop the cable through one end of swivel,have you got photo of detail you could show us.

Thanks
 
Darin,I like your setup with the fishing swivels ,do you still loop the cable through one end of swivel,have you got photo of detail you could show us.

Thanks
I'll try to get a close-up pick... I do loop the cable through the end of the swivel. The smooth ring is a much better place to have the cable than the sharp edges of the 4-40 Dubro threaded clevis rods.

If I set this up again, I think I'd forgo the clevis rods and just use the swivels directly to the steering arm. It's kind of a tight fit right now between the steering arm and the transom boots.
 
How were you going to attach swivels to steering arms, do you use a swivel with snap clip one end..
Currently, the snap-clip style swivel end is going through the 4-40 threaded clevis rod. If I were to do this again, I'd forgo the clevis' all together and just run the swivel clip end through the holes in the steering arms... In the event of a hard flip, the snap-clips are what give way. I keep a stockpile of them on hand and if I can't bend them back into shape, I just replace the snap-slip part. Much easier than replacing the entire cable assembly after IT snaps...

Darin,

Why was the cavitation plate modified "cutdown"? Any benefit doing this?

Thanks

Pete
In my experience with these, because FE motors don't have to "get on the pipe", the cav plate isn't needed. I'm not sure if there are any tuning benefits to having a full cav-plate in place, but thus far, I haven't missed having mine cut-down on the Lynx. Speed and handling both improved when I trimmed it down. Since I'm doing consistent 1:33.xx heat race times, with a current low time of 1:31.34... I feel it's working out well. :)

Again, this is with an FE motor, which has full-power on demand, all the time, so the props we can get away with are much different than what you'd use on a Nitro tunnel.
 
I was doing some final prep and cleanup to Ken's boat, and I couldn't resist... I had to throw a quick polish on the OS Lower... Hope it doesn't slow him down too much :)
 
Finished up prepping the prop for Ken's boat. Should be a pretty close duplicate to my race prop, which provides good speed in the straights, and handles GREAT. I've tested props that were faster in the straights, but always at the expense of handling and race-water stability. With this prop setup, I can drive the boat anywhere on the course, in about any water, and I'm still fast enough to hold them off in the straights. A good place to start, for sure!

Need to take her out for a shakedown run to make sure I have everything in place. Once that's confirmed, I'm shipping the package back to Ken and he'll hopefully take it with him to the Michigan Cup later this month.
 
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