Delta Force 33 Cyber Storm build log and questions

[SlickZERO]

Foam flotation

In stead of trying to stuff pool noodles in the nose I ordered some marine 2 part urethane 2 lb foam from US Composites. After experimenting with expansion rate in a thin plastic cup and to see if it pushed it out (which it didn't, I got up my nerve and went for it. I did it in 2 pours figuring less chance of pushing the deck up. Worked great! When hard it sure stiffened up the nose and deck and is more flotation than loose pool noodles. It may be a week or so before my next post. Waiting on the strut and rudder. I want to install them before I place the motor, esc, batteries, etc. for balance.
06 Foam in front.jpg

[Tamelesstgr]

Coming along nicely, great job! How much was the expanding foam, I have a lot of extra space to fill up in my 32" v-hull.

[SlickZERO]

Coming along nicely, great job! How much was the expanding foam, I have a lot of extra space to fill up in my 32" v-hull.

Thank you! The smallest they sell is about 1.7 quart total for both parts. Plenty for many boats and experimenting. It was 22.50 + about 8.00 shipping to Florida.

http://www.uscomposites.com/foam.html

[Heath M]

Good job on the foam, i need to do the same thing in the sponsons of my lobster hydro.

[SlickZERO]

Prop holder

To work on props I made a quick, easy, and basically free holder. I used a scrap piece of 1” x 2” pine about 8” long. Using an allen socket head 10-32 bolt about 2 ½” long I drilled a hole in the end just bigger than the head. Then glued it in the hole with JB Weld. Next cut and sanded the wood to about the size of the prop hub. Clamp it in my vise and file/sand/polish away.
Boat prop holder.jpg

[SlickZERO]

Prop & rudder distance from transom

Received the strut and rudder today. The front of the rudder would be 3 1/4" (about 85 mm) from the transom. The front of the prop hub would be 2 5/8" (about 67 mm) from the transom. So the rudder will be offset to the right but behind the prop. I see boats with stingers that the prop is about even with the rudder. The stinger looks to be about 3+ inches. Does it mater how far the prop is from the transom with regard to the rudder? I guess I could use a stinger if the mounting bolts are far enough apart to clear the flooded tube.

[Heath M]

They will be fine with those distances, by the time the stub with drive dog and prop go into the strut the rudder should be in front of it, meaning it won't be in the prop wash.

[SlickZERO]

Strut installation

I installed the strut with ½” spacers to move the prop back about in line with the rudder. It is about where it would be if I had used a stinger. It is fully adjustable from top to bottom of the flooded tube. Also if needed I could move it forward or back changing the spacers. I can slightly change the side thrust by shimming under the right spacers. The spacers are extremely hard nylon. They come in many sizes and are used for firewall mounting a gas engine in airplanes.
07 Strut side.jpg08 Strut rear.jpg

[SlickZERO]

Servo mount

I bought the OSE-80090 lay down servo mount from OSE. Very well made! It is adjustable and fits a standard size servo like a glove. Servo will not move. If I installed the servo with wood blocks or a standard mount with servo screws it would be hard to remove. With this one once mounted you can remove the servo by taking out the top 2 bolts holding the strap and simply slide it out. I love this thing.
09 Servo mount.jpg

[Heath M]

They're a great mount, i have a red one for my up coming lobster build :)

[SlickZERO]

Motor and tube mounts

After balancing with motor, ESC, batteries, and servo I determined where I wanted the motor. I bent the tube for proper alignment and adjusted the motor and tube mounts. With everything locked down and in “perfect” alignment I added epoxy with milled fiberglass to the outside of the mounts. I filled it up to the little holes in the sides of the mount. Next I am going to remove the motor and glass up the inner edges to the bottom.
11 Motor mount side.jpg12 Motor mount side top.jpg10 Motor mount rear.jpg

[SlickZERO]

Battery mounts

With everything temporarily installed I marked the battery location for 30% COG. Plenty of room to move them for balance. I decided to velco strap them to the floor against the flooded tube. I wrapped the batteries with wax paper and the velco straps. Then I epoxied the straps to the floor. Next I added a piece of carbon fiber over the straps. Once again I wrapped the batteries with wax paper and set them in place to hold the carbon fiber flat on the straps. That “should” keep them in place. I will use a small piece of velco between the slight humps where the straps are to keep them from sliding in the straps. That is as low and centered as I could get them.

13 Battery straps.jpg14 Battery straps 2.jpg

[SlickZERO]

Rudder

I reversed the linkage pin for a straight shot to the servo and installed the rudder. Since 2 of the bolts come from the inside I made a template from heavy paper. Sort of like a gasket. Then after drilling the 2 open holes I use the template to locate the other 2. With the spacers the prop is about even with the rudder.
15 Rudder.jpg16 Rudder 2.jpg

[785boats]

Looks like she's ready to get wet now.
Well done. Nice build.

[SlickZERO]

Disclaimer

I hope no one is thinking this is a proven setup done by an "expert" and is "the" only way to do it. I have been building models of all kinds for 50 years including some boats but this is my first mono. I came up with the design based on reading message boards, looking at pictures, and advise given to me on these boards. Then using T.L.A.R. (that looks about right) it is coming along. It is quite different from the RTR boats I see at the lake. It will be interesting to see how it performs???