DF Vortex 34 Hydro Build

[CraigP]

Hi All,

New to OSE, but been in boats a long time. This is my first FE build, I ran 0.40ci nitro motors in a 36" plywoodhydro hull some years back. I have some stuff stuck over on another thread, I'll copy/paste over to this. The forum scene is new to me, so just let me know if I can use it better. I have a thick skin, and love to have fun. I take this hobby seriously, but seriously folks, what's to be real serious about? It's all good! I spent close to 40 hours reading posts and learning, before even stepping out to post! Really good stuff on this forum!

[CraigP]

ProperChopper and I started chatting about this hull. Here's what I had on the other thread:

What prop did you end up with? I'm putting an 8S, Leonard 40X72 1050kV to start, then I have a 1250 40X82 motor to kick it a little harder. It's been a while for me, but I'm really looking forward to going electric, gas powered boats were a PITA! I was wondering if you could share what prop you are currently working with. I have Grim Race 38X55, 2 blade High Lift to start out with. I have a Grim Racer 40X57, 3-blade high rake prop to step it up. Is a 42X63 prop about it for this hull?

I'll get some picks on the sponson mods I'm going to be doing. The room in this hull is awesome, love that! I plan on putting the length of the four 5200, 2s batteries across sideways, just starting at the top of the hatch. They go out across the drop off for the sponsons. Thinking of mounting a floorboard for the batteries in there. I want the CG weight components split out, getting weight well forward and placing the front of the motor 13-7/8" from the back of the transom. That still leaves ample room for the ESC and Cap Board in between the motor and the battery pack. I think about CG like a teeter-totter. The longer the arms are from the fulcrum, the slower they move. When the arms get short, then the speed of the teeter-totter goes up dramatically, which represents the boat porpoising, which is not the play. I'm setting my rudder to the left like your model. That seems to make the most sense for a right turning boat running a CCW prop. Prop torque will try to pick up the left side, so setting the rudder left helps stake that side down.

Another trick I was going to employ was to shim the left side sponson up about 1/8" from the right. This really helped in GP boats for turning. My brother is still running in GPW, has a 28', 500CI blown on alcohol motor. (Check out YouTube, search for GP55) I know the dynamics don't entirely scale, but weight shift and corner planting should involve the same physics.

Sorry to load you up this way, I just loved the way your hull turned out and value your building skills and experience tremendously. One more point to ask you, strut angle. I'm looking at 17 degrees, going into a single 10" radius bend to the strut. There is something I want to try... I found that the stainless steel tubing on OSE was a perfect fit for the 0.187" flex cable without a liner. It has about 0.004 - 0.005" per side clearance, perfect for grease. The stainless has a thicker wall than the copper tubing normally used. Also, I find the "stickiness" of stainless to be far less that copper, something that is termed "stiction", so I believe it will not have a tendency to grab the cable. You think it's worth the try?

Well, ProperChopper, getting long here. I hope that we can meet up some time, I have enjoyed getting to know you some on the forum. I promise to get pics out on the build. You know I just hate stopping work to take pictures, but they can be very valuable and may help others enjoy this great sport!

[CraigP]

I made up an AutoCAD drawing showing a Side View of the drive line angle I want to use on this boat. Having it in AutoCAD let's me really explore options. This drawing will grow as the build progresses.

[CraigP]

I'm making this an 8S system. I know many of the viewers will say that's too much, but what I'm trying to accomplish is to make delivered power more with voltage and bring the current down. The secret here, in my opinion, is to select a motor that has a higher impedance than motors rated to run at lower voltages. Impedance is not resistance. It is the dynamic resistance the motor puts up under load conditions, and has much to do with both initial coil resistance and the initial coil inductance. The coil resistance is what many people see on the motor sites when they show motor specs. It has NOTHING to do with the actual impedance while running, unless the prop stops completely while still getting a load speed signal.

So, I have a Leonard 4074 1050kV motor, rated to 45V. The Leonard web site clearly shows the initial resistance higher, indicating it has more windings in it. So initial inductance is higher as well. So the key to me to making this work, it to NOT BE STUPID and put a bunch of prop, or motor load on this. I have a Seaking 130 HV, but really wished I had a Swordfish data logging unit instead. That's the only way to go! If I do this right, then I should get increase run time by dropping the current that is required of the batteries. It's better on the batteries and the whole electrical system in general. I'm using four, 5200mAH in series running to the stated motor and ESC. I do have a Leonard 4082 1250kV motor to put in there once I learn about prop capabilities on this hull.

[CraigP]

Shot of the component placement

Here's a pic of the planned component placing. I can move the batteries +/-1" from there, should give me good CG tuning range... The motor is where the CAD drawing I posted earlier indicates it needs to be to get a 17 degree stuffing box.

[properchopper]

ProperChopper and I started chatting about this hull. Here's what I had on the other thread:

What prop did you end up with? I'm putting an 8S, Leonard 40X72 1050kV to start, then I have a 1250 40X82 motor to kick it a little harder. It's been a while for me, but I'm really looking forward to going electric, gas powered boats were a PITA! I was wondering if you could share what prop you are currently working with. I have Grim Race 38X55, 2 blade High Lift to start out with. I have a Grim Racer 40X57, 3-blade high rake prop to step it up. Is a 42X63 prop about it for this hull?

I'll get some picks on the sponson mods I'm going to be doing. The room in this hull is awesome, love that! I plan on putting the length of the four 5200, 2s batteries across sideways, just starting at the top of the hatch. They go out across the drop off for the sponsons. Thinking of mounting a floorboard for the batteries in there. I want the CG weight components split out, getting weight well forward and placing the front of the motor 13-7/8" from the back of the transom. That still leaves ample room for the ESC and Cap Board in between the motor and the battery pack. I think about CG like a teeter-totter. The longer the arms are from the fulcrum, the slower they move. When the arms get short, then the speed of the teeter-totter goes up dramatically, which represents the boat porpoising, which is not the play. I'm setting my rudder to the left like your model. That seems to make the most sense for a right turning boat running a CCW prop. Prop torque will try to pick up the left side, so setting the rudder left helps stake that side down.

Another trick I was going to employ was to shim the left side sponson up about 1/8" from the right. This really helped in GP boats for turning. My brother is still running in GPW, has a 28', 500CI blown on alcohol motor. (Check out YouTube, search for GP55) I know the dynamics don't entirely scale, but weight shift and corner planting should involve the same physics.

Sorry to load you up this way, I just loved the way your hull turned out and value your building skills and experience tremendously. One more point to ask you, strut angle. I'm looking at 17 degrees, going into a single 10" radius bend to the strut. There is something I want to try... I found that the stainless steel tubing on OSE was a perfect fit for the 0.187" flex cable without a liner. It has about 0.004 - 0.005" per side clearance, perfect for grease. The stainless has a thicker wall than the copper tubing normally used. Also, I find the "stickiness" of stainless to be far less that copper, something that is termed "stiction", so I believe it will not have a tendency to grab the cable. You think it's worth the try?

Well, ProperChopper, getting long here. I hope that we can meet up some time, I have enjoyed getting to know you some on the forum. I promise to get pics out on the build. You know I just hate stopping work to take pictures, but they can be very valuable and may help others enjoy this great sport!

I'm still testing props. I've used a 452/2 and a 450/3 - both Octura's. [One thing is that with the TP Power 4070, which is actually 40mm X 100mm, I could spin anything with all that (silly/unnecessary) horsepower.]

Your 8S 1050KV setup may want (at somewhere near 34K rpm) a larger diameter prop - your 4072 should be able to handle larger wheels - depends how fast ( and how long) you want to run. We're in somewhat uncharted territory with this hull - AND both Jay and Howard's V34 are (like me) rigged for 4S2P "P" Class racing so our props may not be the ones you'll do best with.

The stainless stuffing tube makes sense - theoretically less coefficient of kinetic friction 'tho in my case I've got enough HP that it won't matter much. One thing ; in your diagram your stuffing tube resembles two straight sections with a bend in the middle. Better to have more of a continuous gentle "curved" shape.

You are correct about prop torque and its effect on the LF sponson lifting. I 've added weight in the LF tip to minimize this.

[CraigP]

That's a 10" bend radius in there now, I'm going to try some bigger ones and see what it looks like. Trying to shoot for a 1.25" strut centerline depth, I think the sponson work should help make that happen. Not easy changing the strut depth once the boat is complete! I'm thinking to start at running the prop at a neutral angle, it may need running the prop down about 1.5 degree.

Yeah, my wheels are small! I have some nephews and nieces that would like to learn how to drive, so I thought they would be good learning props, for them and me! It was ALOT of work thinning and polishing those wheels, my freaking fingers hurt... Now they got that nice little "ring" to them when you wipe your finger across the edge. I'll cup them a bit after working out the CG and basics.

Actually shooting for about 26KRPM's on the 1050 motor with the prop staying hooked up. I may have to run the switching frequency at 12Khz to limit the power to the motor.

Appreciate your feedback...

[CraigP]

New CAD Print, 15" Radius on Stuffing Box

Here's 15" and you're right ProperCHopper, it does look more gentle. I'll have to get a big piece of tubing, that radius ends about 3/16" from entering the strut. I'll have to bend it, then cut it back...

[CraigP]

Sponson Pics

Hi All,

I've been working on my DF vortex 34 Hydro build. Going slow, been hammered at work! What's that all about? Doesn't my boss know my htydro build is more important? LOL!

I have some sponson rework pics to share with you. As posted earlier, the stock sponsons are not what I want. They have way too much lift angle, too much side angle and they "swoop up" towards to front, which makes them sticky in rough water. A long time ago, I ran sponsons like the pics and found that the boat was much more stable all around. That was on nitro, hoping the FE boat does the same.

The wooden rails put down as a base frame are made of laminating 5 pieces of 0.25"X0.25" basswood rails together with marine epoxy. They are incredibly light! I then put in fiberglass and resin inside the channels to re-enforce the epoxy bond. The actual "skin" of the sponsons is T6061-T6 aluminum plating, 0.031" thick. They are held by 4-40 brass wood screws. This thin aluminum I found holds up much better than wood, that eventually starts to show the rails through it after a couple of seasons of pounding on it.

The site won't take all the pics, so I'll put them on in separate posts.

Race on All!

[CraigP]

SPonson Pics #2

Second set of sponson pics.....

[CraigP]

Sponson Pics #3

Third set of sponson pics....

[rol243]

looks nice and neat but i wouldn,t like to race against this Iron Maiden , lol.

[CraigP]

It does have a battle ready look! All the materials added 0.74lbs to the boat. The sponson design was originally created by Ron Jones. It flattens out the angles, allowing the boat to "skip" across rougher water, like a skipping stone. When the boat hits a crest, it pops up a bit. That produces negative strut angle that brings the boat back down. The rails deepens the sponsons, which opens the air bleeds behind the sponsons. This controls the air under the boat more effectively than air dams. Air dams work to a point. Once beyond that, the boat will snap-flip because the dam itself creates additional trapped air.

[Mxkid261]

Interesting sponson work. My 24 vortex runs great in a little chop. Maybe the larger hull rides differently.

[CraigP]

I was referring to ugly race water. The other goal is WOT turns, in race water. Others on this site and other sites wouldn't put the 34 Vortex in its stock configuration into the stable category. They like to sponson walk and they run light on the front. Stock, they do trap too much air, resulting in quick executing blow overs. They also like to hook in corners when hitting side swells. This boat will skip, never getting to that sponsons never touching ride. Some say slower, I say you have to finish to win! You can't win when the boat is upside down... definitely not a SAW configuration!