I need some setup advice for my electric tunnel

[crowebar]

Hey Unc or any anyone else, I'm haveing a little trouble holding my new 12 cell tunnel on the water. Mike Hughes built me a Dumas 3.5 ultra light a few weeks ago. It was 14 ounces with the cowl.

Anyway, it's pretty much the same setup as what we ran years ago except the power. I've got an Aveox Brushless motor on 12 cells and an ABC 45/55 that I thought was going to be conservative. As it turns out it's much faster then I thought it would be and wants to take flight at WOT. I dropped the outboard where the top of the prop hub is below the sponsons and have a little down angle and it still takes flight. My next move is to put the batteries up front and the radio gear in the back. Should I try working the motor depth and angle more first?

Second problem. It hooks like mad! It's a rare occasion when it actually completes a corner! One other note. I cut the skeg down about half way on the lower unit a few years back for a strightline record. Would this be my problem?

I really hope that it's just the fact I don't have a clue with tunnels and there is an easy fix.

Thanks,

Dick Crowe

 

[Jack Garcia]

Crowbar,

Most assuredly it's the short skeg. It's so tiny that it's hardly effective. Two solutions, 1, lower the engine so's it's much deeper in the water. Or 2, obtain a new foot with a longer skeg.

My two bits, JG

 

[Jack Garcia]

Crowebar,

P.S.

By the looks of the boat in the picture, looks to me like the batteries need to be positioned further back. The CG (balance point) is too far forward. CG should be about 30% from the transom

JG

 

[crowebar]

Thanks Jack, I'll work on the skeg. I had a suspicion that would cause me trouble.

I don't think the boat would stay on the water with the batteries in the back, much less float. I did try and run it with one in the middle and one in the back but it would blow off way too easy. It blows off too easy with the batteries in the middle. I'd like to leave them there though. Perhaps I should drop the motor and kick it in even more.

I'll keep trying!

Dick

 

[Jeff Torgalski]

I have a very old K&B lower unit that has a skeg that was originally manufactured to about the same length as in Dick's pictures here. Is it true that a skeg of that length can cause the boat to skip out of the water more frequently?

Jeff

 

[Jeff Torgalski]

Dick,

You said your boat hooks? Did you put on stumble blocks?

Also, I recently learned that if my Villain tends to pull itself underwater, I should trim the engine so it's trimmed up a bit more.

Hope this helps,

Jeff

 

[Mike Hughes]

When we ran these boats 12 years ago we did not have a problem with hooking. We also went a lot slower. I would try the stumble block suggestion. This will help the hooking. I lighten the nitro boats so that I could transfer the weight forward without adding any weight to the boat. This way right before I would start to enter the turn I would get out of the throttle, the weight up front set the boat, and around the corner I went. I seem to remember that we had to drive the electrics the same way.

Mike

 

[Jack Garcia]

Jeff,

Do you mean skip when turning? If that's the case, I would say that the engine is too high and the skeg is being surfaced to a degree when the boat lays down for the turn. This minimizes the effect of the skeg to hold the boat steady. My suggestions to Crowebar apply here as well.

Good luck Jeff.

 

[Jeff Torgalski]

yep, it skips sometimes in gradual high speed turns, and barrel rolls. It was rough water when it happened, but I didn't recall such a problem before I used that lower.

Thanks Jack,

Jeff

 

[crowebar]

Hey Guys, Thanks for the help. I've got the big skeg again, I dropped the motor lower about 5/16ths below the sponsons from the center of the prop and kicked it in abou 1 degree.

I'll go run it today and see what happens.

Thanks,

Dick Crowe

 

[crowebar]

I'm back in business. Long skeg and low motor. It's stuck like glue and I couldn't get it hook no matter how hard I tried! The polar opposite from the last time out! Now I can start loosening it up again and getting it ready to race.

I forgot how much fun tunnels are!

Thanks for the tips!

Dick Crowe

 

[Jeff Torgalski]

Dick,

So tell us your setup...what kind of speed control / motor / batteries are you using? About how long are your run times?

Jeff

 

[crowebar]

Jeff,

I'm not sure what the hot ticket is right now. I'm running an Aveox 1412 1.5 and ABC 42x55 prop with a Hacker Master/Navy 77 speed control and 12 2400 cells. I'd like to replace the Aveox with my Hacker B50 7XL which would probably spin a x442 but would rather get the bugs out with the Aveox. I haven't checked the runtime but it's probably about 3 min or so. I'll toss a GPS on it next time out and see what it's doing for speed. The fastest Electric tunnel I've seen runs in the mid 40's but probably wouldn't have much run time. I'd like to run 40 for 3 min but I could be dreaming.