Dual Engine DF Vortex34 Build

[srislash]

I know whatcha mean. Paint is one my faves, not so much the actual work of it but the planning and design of it. I read a cool trick for avoiding runs awhile back. Doing clear is the only place this is an issue for me but it works well. Let me try to find it or put it into words for you.

Also, Was it you or Travis that came up with the strut seal thing a bit ago? Now that I typed it I’m thinking you.

[CraigP]

I started the seal, but posted on Trav’s ball bearing strut/shaft thread. Remember he puts about 5-6 ball bearings in. I use the lead/Teflon because if you keep water off of them, they will last a very long time. So when I seal the back, there is no grease loss, and no water intrusion. I ran the Vortex #1 and the DF29 Mono all summer and never took the shaft out. I took it out in the fall, and found I didn’t need to do that. Holds grease like a wheel bearing! It didn’t seem anybody had any interest, so I didn’t go into great detail. I found a great cutter to do the job, just need a table mount drill press... If you’re interested, I’ll post more detail on the process.

[srislash]

I started the seal, but posted on Trav’s ball bearing strut/shaft thread. Remember he puts about 5-6 ball bearings in. I use the lead/Teflon because if you keep water off of them, they will last a very long time. So when I seal the back, there is no grease loss, and no water intrusion. I ran the Vortex #1 and the DF29 Mono all summer and never took the shaft out. I took it out in the fall, and found I didn’t need to do that. Holds grease like a wheel bearing! It didn’t seem anybody had any interest, so I didn’t go into great detail. I found a great cutter to do the job, just need a table mount drill press... If you’re interested, I’ll post more detail on the process.

Oh man and here I was looking at a buddy’s Sherline lathe and mill. Mini/hobby stuff but good quality. I like the idea of a sealed strut so feel free to post info that I can absorb.

[CraigP]

Oh man and here I was looking at a buddy’s Sherline lathe and mill. Mini/hobby stuff but good quality. I like the idea of a sealed strut so feel free to post info that I can absorb.

Oooh, I want one!

[CraigP]

First run of Dual Vortex 34 Hydro Video! The boat ran well, didn't drive it at full throttle, but did get close to 5 minutes on it. I was very pleased with the boat's riding attitude and the flatness in the corners. But there was an issue... It appears I missed the power calculation by a wide berth. The 3650 motors are rated for 600W. When I brought it back in and took off the hatch, it wreaked of motor winding insulation! The motors didn't short out, but they are toasted! I recharged the batteries and calculated I was running about 850W on each motor, way overboard! This boat had the 3650, 2090KV motors running a 4s, 2p battery pack. The 3660 motor is rated for 800W, but this run was over that, and I have some larger props to run. There's no problem with the T-120A ESC's, the running current to each motor was about 75A, where I was planning on 50A. Apparently, this big ol' boat needs the power to push her big ass around the course!

So, I ordered 3674, 1400KV motors and I'm going to install a 6s, 2p battery back. I should have plenty of power with that, they’re rated for 1200W... This first run was using Chris's prepared, matching X442 props. The props are spinning to the inside right now. I read Larry's post on another thread about the turning difficulties with this configuration. I'm going to try it both ways. But I was pleased with the turning of it out of the box. I don't think the front wing is playing a major role in the corners, but it definitely helps to keep the nose down on the straights. Wind was gusting to 20MPH during that run (you can hear it on the video) and it was coming across sideways on the straights. But the boat has to run in the wind, I live in Oklahoma! Looking forward to upgrading the power system and getting back out there!

Note: This power train will end up being exactly double of the power train in my UL-1, so I should get some interesting power comparisons between the small and larger hulls.

https://youtu.be/e00Rb0vbVb8

[Fluid]

Nice run, but you got me nervous running so close to the bank! Five minutes at part throttle is tough on the ESCs but your problem was the motor. Full throttle may have reduced amp draw and motor temps. In a 2-minute oval heat would not have been a problem.

Every successful oval racing twin hydro I've seen - and that’s dozens - run two normal-rotation props. They (including two USA-1 drivers) claim that turning is much better than counter rotation. Watching many Open Hydro gas races the twins aren’t much faster in top speed, but acceleration out of turns is much better than big singles. It would be interesting to see what you find out with an FE hydro. This isn’t a catamaran.


.

[CraigP]

Fluid, I make my wife nervous too! I’m trying to pick up subtle turning characteristics and was checking the watering system. I knew the part throttle would heat the ESC’s but they were only about 130 degrees. I had an accurate timer on the run, and the mah I put back in the battery had each motor pulling about 77A, way over my initial projection. But 150A for both motors, at 4s, is believable. I couldn’t find 4s larger motors, so I opted to go 6s.

I’m going to try all three rotation variations, inside rotation (current), outside rotation and same CCW rotation. But I like the physics behind inside and it turns! The whole purpose of this boat is to experiment and learn. Other details, the turn fin is a straight blade canted inside at 8 degrees. The rudder as a negative camber of 1.5 degrees, it’s laid back. The propellor spacing is 3.5”, close enough that I felt I wouldn’t need any speed reduction on the inner prop.

I appreciate you checking it out. It will be faster on the next video..

[Brushless55]

5min run?

First run of Dual Vortex 34 Hydro Video! The boat ran well, didn't drive it at full throttle, but did get close to 5 minutes on it. I was very pleased with the boat's riding attitude and the flatness in the corners. But there was an issue... It appears I missed the power calculation by a wide berth. The 3650 motors are rated for 600W. When I brought it back in and took off the hatch, it wreaked of motor winding insulation! The motors didn't short out, but they are toasted! I recharged the batteries and calculated I was running about 850W on each motor, way overboard! This boat had the 3650, 2090KV motors running a 4s, 2p battery pack. The 3660 motor is rated for 800W, but this run was over that, and I have some larger props to run. There's no problem with the T-120A ESC's, the running current to each motor was about 75A, where I was planning on 50A. Apparently, this big ol' boat needs the power to push her big ass around the course!

So, I ordered 3674, 1400KV motors and I'm going to install a 6s, 2p battery back. I should have plenty of power with that, they’re rated for 1200W... This first run was using Chris's prepared, matching X442 props. The props are spinning to the inside right now. I read Larry's post on another thread about the turning difficulties with this configuration. I'm going to try it both ways. But I was pleased with the turning of it out of the box. I don't think the front wing is playing a major role in the corners, but it definitely helps to keep the nose down on the straights. Wind was gusting to 20MPH during that run (you can hear it on the video) and it was coming across sideways on the straights. But the boat has to run in the wind, I live in Oklahoma! Looking forward to upgrading the power system and getting back out there!

Note: This power train will end up being exactly double of the power train in my UL-1, so I should get some interesting power comparisons between the small and larger hulls.

https://youtu.be/e00Rb0vbVb8

Fluid, I make my wife nervous too! I’m trying to pick up subtle turning characteristics and was checking the watering system. I knew the part throttle would heat the ESC’s but they were only about 130 degrees. I had an accurate timer on the run, and the mah I put back in the battery had each motor pulling about 77A, way over my initial projection. But 150A for both motors, at 4s, is believable. I couldn’t find 4s larger motors, so I opted to go 6s.

I’m going to try all three rotation variations, inside rotation (current), outside rotation and same CCW rotation. But I like the physics behind inside and it turns! The whole purpose of this boat is to experiment and learn. Other details, the turn fin is a straight blade canted inside at 8 degrees. The rudder as a negative camber of 1.5 degrees, it’s laid back. The propellor spacing is 3.5”, close enough that I felt I wouldn’t need any speed reduction on the inner prop.

I appreciate you checking it out. It will be faster on the next video..

Trying to follow the math here
75-77amps per motor for 5min?
are you running 7500mah packs for a total of 15,000mah?

your first post says 850 watts that would = 57amps on 4s
75amps on 4s = 1,110 watts

[Old School]

Craig,
TFL do an SSS 3682 1650kv 3600 watt ' D' wind motor. Refer link. A little low kv for 4s and a little high for 6s and just right for 5s.

https://www.ebay.com/itm/28250749303...MakeTrack=true

[CraigP]

Trying to follow the math here
75-77amps per motor for 5min?
are you running 7500mah packs for a total of 15,000mah?

your first post says 850 watts that would = 57amps on 4s
75amps on 4s = 1,110 watts

They were two 4s, 8000mah in 2s configuration, for 16,000mah. And you’re right about the math, I transposed the the 7 and 5, it’s supposed to be 57A. What the f—k is wrong with me?! I’ve been doing that lately... Nice catch and correction, thank you! The motor is rated for 40A, 600 W at 4s voltage. As Fluid pointed out, probably not an issue for short, heat class racing. But I’m a sport boater, so runtime is important and I can’t run the over rate that long...

[CraigP]

Craig,
TFL do an SSS 3682 1650kv 3600 watt ' D' wind motor. Refer link. A little low kv for 4s and a little high for 6s and just right for 5s.

https://www.ebay.com/itm/28250749303...MakeTrack=true

Yes, I have a 3674 1700kv right here on the table. It is too fast for normal 6s operation for my liking. But that would be a kick butt motor to use for a super SAW run. Not sure I got the stones to push it that fast... Would hate to see it crash at close to 100mph, but what a video, eh?