NTN – 600 Hull Rigging – Part XIV

Well, Friday, the gasket came out ok, but when I grabbed and pulled on the edges, they came off easily. So I pulled off and scratched the whole thing, and saved this part for later. I know it works, I will just have to sand that area harder next time for better adherence.

Saturday and Sunday, I worked on the motor mount. I decided to make something similar to this one here, so I got some aluminum sheets, liquid bolt lock, and many Allen head M2, M3, and M4 bolts from the hardware bazaar in Karaköy.

I designed the part in SketchUp as always. The final form probably will not look like this.

Motor Mount SU

Motor plate drawn in SketchUp. The center hole I drilled was actually 5 mm, with a 1 mm countersink. Side bracket holes also changed.

I mounted a printed copy of the design above on a 1.5 mm thick, 35 mm x 45 mm aluminum sheet for easier drilling. I stilled counted turns on the hand-wheels of the mill to be sure though.

It was too late when I got to Karaköy on Saturday (most close at 14:00), so I couldn’t find thin steel brackets with slots (and I thought I’d be content with what I got in stock at home, and the aluminum strips I could cut from the 1.5 mm plate). The lightest and most suitable part I could find to use for the side brackets was a 1 mm thick steel corner bracket (I was hoping to find more of these in Karaköy), which I flattened in the vise and cut in half to make two side brackets.

Motor Mount Plate

Checking the holes. Motor mount plate cut from 1.5 mm aluminum sheet. 5 mm center hole, 3 mm mount holes, and 2 mm side bracket holes.

Plate Bolts Box

Motor mount plate along with M2 and M3 bolts, nuts, washers, and M3 and M4 setscrews in their box.

I had to open two more holes (M3 this time for easy adjustment) for the side brackets, since the holes in the motor plate were too narrow for the forks (I ended up with, after the cut in the middle of the bracket. I wish I had one more) with holes.

Motor Mount Parts

1.5 mm aluminum plate and 1 mm steel corner bracket pieces.

It was time to bend the forks to 90 degrees. I used the bolted motor plate to align the forks in the vise. Then I removed the bolts and the plate, and hammered the fork down to 90 degrees. Did this for each side bracket. No motor width adjustment for this cheap copy.

Plate Bracket Bend

Aligning the side bracket in the jaws of the vise using the bolted motor plate.

Bracket Hammered

Side bracket’s fork with 2 mm holes, after being hammered down to angle.

It wasn’t too late when I realized the side bracket would be too narrow for the water nipples of the motor’s cooling jacket. I thought the plate was a bit thin anyway, so I added another wider layer for support. I taped and bolted the motor plate to a bigger plate for the cutting, milling, and drilling.

Plates Bolted Taped

Mounted the old plate on the support plate using masking tape and M3 bolts and nuts. Those M3 bolts moved to horizontal 3 mm holes for easier milling later.

The motor plate is now about 56 mm wide and 32 mm high (motor diameter is 29.1 mm, water nipples stick out to 11 mm). I aligned the holes of the side bracket on the support piece using the vise as seen in the picture below.

Mount Vise Colors

Jaws of the vise help align the side brackets on the motor plate.

Motor Mount Vise

In darker colors.

I temporarily bolted the side brackets and the motor (with the 3.2 mm to 4 mm coupler on the shaft) on the plate for a test shot. Here are some pictures below, shot from different angles. It would be nicer if I had suitable a flex shaft collette, but this double setscrew coupler (pressure from both sides for better alignment) should do..

Mount on Motor Top

The coupler was 3 mm to 4 mm before I enlarged the 3 mm hole to 3.2 mm for the 3.175 mm motor shaft.

Motor on Mount Front

Still needs work, such as cutting and rounding the corners, drilling more and bigger holes in the small plate to make those 3 holes look better, and polishing the faces.

Motor on Mount Box

All in the box, which is as wide as the future plywood rails will stand.

I will probably work on the plywood rails and the assembled metal parts tomorrow evening.

NTN – 600 Hull Rigging – Part XIII

Last night, I worked on the gasket for the hatch. As always, I used masking tape to cover the areas to be protected from that red demonic paste (can withstand temperatures from -60 ° C to 300 ° C). I decided to apply the gasket to the inner edge of the groove around the hatch. The hatch cover’s outer edge (along with the sides, but that would probably  make it hard to fit the cover there later) is the only part that is in contact with the groove.

Tapes Gasket Start

I limited the area for liquid gasket using masking tape.

Gasket Complete

Finished gasket, before putting the hatch cover on.

Later on, I applied the gasket to the whole inside edge and above the transom. Using coffee / tea stirrers with radius ends helps create a concave shape in the corners during the application. I don’t need a too tight fit there. Working on the curves with masking tape wasn’t all that hard.

Hatch Cover Stretch Close

Hatch cover on.

There is also a small gap between the groove and the cover in the bow side, thanks to cheap molding. I filed that area generously, to create a thicker gasket there (masking tape also raised towards the bow).

The whole thing should already be cured. Hopefully, it will not be hard to separate the cover from the hatch. I’ll probably start working on the shaft hole and the rest of the drive system tonight, as well.

NTN – 600 Hull Rigging – Part XII

I have been a bit sick lately (runny nose), so I didn’t do much yesterday in the workshop. I stabilized the ESC right across from the rudder servo, using Velcros. Since the ESC has a large flat base, there was really no need for a bracket. The special RC Velcros I got from HK are really strong.

ESC Velcro

These self adhesive Velcros from HK are very strong and waterproof.

I also connected the loop hose and the hose from the cooling water inlet to the ESC. Considering the location and the direction of the cables and the nipples on the ESC and the motor, I think it would be easier if I had placed the servo on the starboard side (but I copied the ARR version of this hull, and this is how it was done). They actually placed the ESC right beside the motor in the ARR version. Whatever…

Inside Hull Long

ESC placed right across from the rudder servo, for hull balancing purposes.

I think it will be alright, if I can flex the motor cables a bit, and find a good spot for the battery. Since other people recommend moving the COG a bit towards the stern to avoid wet runs, I may move the motor towards the bow, since the battery (heaviest of all – twice as heavy as the motor) will be used for adjusting the COG. I plan on placing it a bit high, but that will probably raise the COG, too.

Inside Hull ESC Bat Motor

ESC stabilized with Velcros. I will probably have to move the battery up (closer to the hatch) for easier cable and hose manipulation.

I will have to start working on a motor mount soon. Since the mount holes on the motor are few and only allow crappy angles for the water nipples (outrunner problems), I will have to think of a work-around.

Hold Motor

The motor mount holes are not really optimal for the water-cooling nipples.

I also filed the holes for the hatch cover tabs. They look and fit better now.

Tab Slots New

Tab slots look a little bit better now.

I will probably be working on the water outlet and a motor mount this evening. I may have to rearrange the hoses and cables somehow.

Specialization is for Insects

specThe Picture is from R.A. Wilson’s (RIP) Prometheus Rising, if I recall correctly. And the words are from R.A. (what a coincidence!) Heinlein’s Time Enough for Love. I haven’t read that one (and I should). Just Stranger in a Strange Land…

This is actually true for the ones with hive minds (swarm intelligence), such as the ants or the bees. These creatures die, when they are away from their fellows. And this is why people, who don’t crave to improve themselves, are doomed to be dependent on others (in a world where you can trust nobody!). Self sufficiency is imminent.

The whole paragraph is as follows:

“A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.”

NTN – 600 Hull Rigging – Part XI

Yesterday, I didn’t do much, other than peeling the masking tape and pieces of paper off of the stern, and appreciating the parts I finally received. The paint job looks ok, but it needs some sanding and polishing on the sides, where the masking tapes were. Here’s a picture of the stern, along with the hatch cover with its tabs.

Cover Tabs Paint

Hatch cover tabs added and epoxied for a better hold. Paint on the stern is now dry and needs polishing.

So I have received a BLDC motor, a BLDC ESC, a stinger drive, two aluminum cooling water outlets, a pair of turn fins that are too small for this boat, and four canopy lock latches that I probably won’t use on this hull. I did not see one picture of this motor from different angles on the net. So I posted some here. Many pictures, little text.

Turnigy Aquastar 2842

Finally, the motor is here!

Shaft Holes

M3 motor mount holes. 19 mm and 16 mm apart.

Stinger Fin Lock Out

From left to right: cooling water outlets, turn fins that are too small, black stinger drive, and canopy lock latches, which I probably won’t use on this hull.

ESC Side

50A watercooled brushless ESC from the side.

Motor ESC Shaft Prop Stinger

Motor and ESC connected after soldering the bullet and T connectors to the ESC. Below, lies the grease tube (along with the flexshaft and the prop) inserted in the stinger drive.

ESC Motor Shaft Top

Another look at the mount holes, along with the drive system.

And here’s the whole deal in the hull. I will probably work on all this tomorrow, since I will be busy with *sigh* social activities tonight. The maiden voyage is nigh!

All In Hull

Put them all in the hull for size comparison.

NTN – 600 Hull Rigging – Part X

Saturday, I worked on the magnetic hatch system. The only strong enough magnets I got in stock were the circular (25 mm diameter) neodymium ones, so I decided to place one in the transom. I was going to place it under the stern, but I thought it would be stronger if I opened a hole for it, coated its top with a thin layer of epoxy, and painted over it. I opened the hole using my Dremel 4000 with a 561 MultiPurpose Cutting Bit on it, after drawing the circle on a piece of masking tape stuck on the stern.

Magnet Hole

I drilled the hole using my Dremel 4000 with a multipurpose bit, and smoothed it with the sanding bit.

Later on I stuck the magnet in the hole and applied some epoxy for stabilization. Epoxy looks like crap due to some fiberglass / epoxy powder added to the surface.

Magnet Epoxied

Magnet buried in epoxy as it tightly sits in its hole. It looks crappy due to epoxy / fiber dust.

Finally, I sanded that part of the stern along with the epoxy on the magnet, and put masking tape and paper to protect the rest of the hull, to prepare the whole thing for the paint job.

Mask Pape Tape

I covered the rest of the hull with masking tape and paper bag pieces. Also sanded off some of the gel-coat.

I applied a couple of coats of red spray paint to the area, then realized I was doing a shitty job, wiped it all off, and resprayed.

Stern Painted Close

Too much paint. Had to wipe it off later, and re-spray from further away.

I also added some wooden tabs (from drink stirrers, painted red, and coated with epoxy) to the front of the hatch cover for stabilization, and opened two slots in the hull for them to enter. Pictures will be in the next post, since the paint on the stern is not dry yet.

Hatch Holes

Holes opened with the Dremel 4000, using 2 mm milling bit. I may need to file them for a better look.

So, I needed a matching piece of steel on the hatch cover, I cut a small piece from an angle bracket I got in stock, and shaped it for better epoxy adherence.

Happy Steel

Piece of steel from a corner bracket was cut and abused, so it will hold epoxy better.

Finally, I put generous amounts of epoxy on and under it to stabilize it on the hatch cover.

Steel Epoxied

Steel buried in epoxy. Put more on to cover it all, after this was cured a bit.

The paint should be dry by now. I’ll see it tonight, when I get home from work. I found out on the net that my packages have arrived at the post office! Thanks to a good friend here (who worked at the post office before, and knows the people there), I went there and picked them up today, before the postman could bring it tomorrow.

NTN – 600 Hull Rigging – Part IX

Great… I fried my only receiver (FlySky FS-GR3E 3-Channel Receiver) last night thanks to a messed up UBEC (thankfully, I had ordered another one, a while ago, just in case). The LED on the receiver lit very brightly for a second, then went off, and never responded to anything afterwards (I tried to re-bind it, like a fool). After a couple of tests, I realized the UBEC’s output was equal to its input (it works with up to 6S = 22.2V)! It had probably been this way for a while, considering the excessive torque and noise put out by the servo, as I tested it last time. Hopefully, the rudder servo still works smoothly. I need to get my damn Motor and ESC soon, so I can simply use the BEC on the ESC!

This week, I should receive a 50A ESC with BEC, a 2800 KV 40 A BLDC motor,  a 55 mm stinger, a pair of 40 mm turn fins, a FlySky FS-GR3E 3-Channel Receiver,  a 4 mm aluminum cooling outlet, a DRO for the BOB of the CNC, and a 48V 1000W BLDC HUB motor for a future project.

Output Voltage

My UBEC betrayed me.

I also made two new 2.4 GHz antennae from the materials I got in stock. One from an SMA to U-FL adapter cable (U-FL end trimmed), and another from an SMA male to SMA male extension cable (thicker and longer).

50 Ohm Coax

The short antenna.

I stripped off 31.25 mm of the shielding on each coax cable. Antenna length for a quarter wave whip antenna is calculated as follows:

λ = Wavelength
c = Speed of Light (roughly 300 000 000 m/s)
f = Frequency of Signal (2.4 GHz = 2 400 000 000 Hz)

λ = c / f
= 0.125 m = 125 mm

So, the length of a quarter wave whip antenna (or the shielding to be stripped from the coaxial cable) should be:
λ / 4 = 31.25 mm

Antenna Length

Length for 2.4 GHz quarter wave whip antenna.

The longer antenna (about 28 cm) needs a plastic tube (with 3 mm ID) to hold it up straight. I tried it with a brass tube (OD = 4 mm, ID = 3 mm), it fits fine, but it’s pretty heavy. I may also shorten this antenna a bit next time.

Heatshrunk Aerial

Finished antenna with brass tube.

Brass Tube

Brass antenna tube in heatshrunk tubing, along with the shorter 50 Ohm coax antenna.

Then I found some Teflon and plastic tubes, and tried them on the antenna and the SMA connectors.

Plastic Teflon

Plastic and Teflon tubes joined together.

I thought it would look better with some (surprise, surprise!) heat-shrink tubing on.

Shrunken Teflon

Teflon and plastic tubes in heatshrunk tubing.

Still looks clumsy, I believe. I’ll think about something else tomorrow.

NTN – 600 Hull Rigging – Part VIII

I completed the SMA antenna connector for the receiver last night. I drilled a 6.5 mm hole in the area, which I had filled with epoxy last time. Then, I put on a suitable o-ring (silicone greased) and a big washer (of which hole was enlarged from 5 mm to 6.5 mm) on top, and tightened the nut until the o-ring was flat. Finally screwed on the 2.4 GHz rubber duck antenna on it.

Update: Crap! I just realized this is a 433 Mhz antenna for my RF modems. I’ll either have to get a 2.4 GHz one with a male SMA connector, or make one from the coax cables (converters / adapters) I got in stock.

Sma Connector

SMA connector with o-ring and washer, from the top.

RX SMA Inside

Receiver (Velcro mounted), SMA connector, water inlet, and pushrod in one picture.

Antenna Mounted

2.4 GHz rubber duck antenna mounted on the transom extension.

Hopefully, I’ll receive the rest of the materials in a day or two. Until then, I may just work on a magnetic system for the hatch.

NTN – 600 Hull Rigging – Part VII

I worked on the antenna mount and the cooling water inlet today. I gave up on the ugly and short cabled original antenna, and decided to replace it with a female SMA connector, which I could use with a 2.4 GHz rubber duck antenna I got in stock. I also made a cooling water inlet using two 4 mm brass tubes and a LED panel mount part.

First, the SMA antenna mount / connector…

I had a couple of SMA to U-FL connectors in stock. So I cut off the U-FL connector, stripped off the insulation, and soldered it to the PCB of the receiver, as it was done to the original antenna. When I closed the plastic box, it looked just fine. By the way, I got the tip from here.

New Antenna Close

New antenna connector soldered to the receiver.

Modified RX

Modified receiver with the new SMA antenna connector.

Since the 8 mm hole I prematurely opened for the previous antenna mount was too big for this connector, I filled it with 20-minute epoxy and left it to cure overnight. It is visible in one of the pictures about the water inlet. Below picture was shot before the 8 mm holes were drilled.

Antenna and Water Marks

Marked the holes on masking tape.

As I could do nothing more for the antenna mount, I started working on the water inlet.

Since the transom extension offers very little space, and I can’t afford to bend the water hose too much, I joined two 4 mm brass tubes, using my soldering iron,  to form an L joint (after cutting each end to 45 angles with a saw). I was going to use my torch for this job, but it was too hot for the brass to hold the solder.

Fresh Corner

This time I used my soldering iron at 350 ° C with regular solder, instead of the torch at 1300 ° C with lead-free solder.

Finally, I polished the part and fitted it in the LED panel mount piece using 20-minute epoxy.

Polished and Joined

The brass piece fits snug in the hole of the LED panel mount.

I applied some liquid gasket to the nut of the LED panel mount part, and screwed it on the main part, which was installed on the hull. You can see the epoxy filled old antenna hole in the below picture.

Hose Outside

Water inlet mounted after liquid gasket was applied to the nut. The white circle is the filled hole, which was too big for the new antenna connector.

I applied some more epoxy to the top of the brass tube, and aligned it towards the starboard side to leave space for the antenna connector.

Hose Inside

I aligned the corner piece towards the starboard side.

Hopefully, I will receive my motor, ESC, and other miscellaneous parts this week. I’ll be working on the antenna connector tomorrow.

AC Motor Speed Controller and NEMA 34 Motors

Saturday, I went and got some parts for the AC motor speed controller I was going to make for a friend, who supplied me with the stepper motor brackets for the MF 70. When I went to the electronics store, which belong to friends of mine, I came some across huge NEMA 34 stepper motors, and immediately bought 3 of them ($155 total, they were more expensive with S&H from China).


48V – 5.6A – 4 Nm – 2415g

Since I have no suitable power supply (48V – 1000W) or driver boards (7.8A) for them, they will sitting on my shelf for a while. Then I’ll convert my BF20L to a CNC mill.

In the meantime, I started working on the AC motor speed controller, which I found here. The PCB is wrong, so I made my own on Proteus Isis and Ares. The values in he schematic are what I used at first.

AC Motor SCH

The schematic copied from the aforementioned site.

AC Motor PCB

My revised PCB.

3D Boards

Board shape simulated in 3D.

Later on, I copied the PCB prints (I made two boards) on a small piece of Press’n’Peel sheet on my laser printer, ironed the sheet on the copper clad for a while,  peel it off when it was cool, etched in Fe(III)Cl, and scrubbed the board with steel-wool under water when it was all done.

PCB Work

Completed PCB’s after scrubbing.

After splitting the boards and drilling the holes, I soldered the parts and completed the board. No cables for the pot yet.

Complete Card Front

Completed card with all parts soldered.

The card did not work it was supposed to. The motor was turning weak at some point and that was all. So I changed some parts as rohart suggested in the comments of the same page. I changed C4 to 22nF and R3 to 33K. I didn’t scrap R2 (when I did, it fried the pot at some point), but changed it with a 47K, and replaced the pot with a 50K one. Then it was running pretty smoothly.

All I have is a 15W Orange light bulb and a 19W Ebmpapst cooling fan to test it, until my friend’s 450W motor arrives. I think it will need much better cooling for such a motor. Here’s a video of both. I think I’ll get better results with R2 changed to 33K and the pot changed to 100K. Turn up the volume to hear the motor change speed.

Update: The card was almost ok with my 125W scroll saw, but I had to change C4 back to 100 nF to be able to control my grinder / belt sander, which has a 250W motor on it. I guess it all depends on the motor’s wattage. None of the parts got hot, the TRIAC wasn’t even warm.

I’ll soon try it with my friend’s 450W mini-lathe motor when it arrives.