New scratch build 24" mono

[Jesse J]

I have uploaded pics to the video section. I measured 70mm Keel to top of mount, with the the center of prop at 7mm above keel.

[jfrabat]

OK, looked at your videos and pictures. And also did a lot of measuring... Lets take a look at the measuring first:

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Transom (top to keel) we have a bit over 65mm (66mm maybe).

So I opened AutoCAD, and imported the 3-view drawing of the units with the dimensions,

p1-outdrive-dimensions.jpg

and scaled the drawings to 1:1 scale and printed it out.

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This should be the real dimensions of the drive (theoretical, anyway!).

With this, I took the front view of the drawing to scale, and check fit in the boat.

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The dot is the bottom of the keel (and I left about 1mm of spacing at the top still). Seems to me this drive will fit!!!

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Of course, I may need to carve out the balsa square I used to hold the canopy in place, and maybe use longer bolts or something, but it WILL fit... What do you think?

Speed, if I run at the same speed as your boat, I am fine with the speed; I do not need more than that, so this is REALLY looking tempting! And 5~10 minutes of maintenance does not sound bad to me at all! And I like the fact that I can run the 4S packs I already got.

[jfrabat]

Just to be on the safe side, I double checked with the side drawing...

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Conclusion: I NEED THAT DRIVE!

[jfrabat]

I pulled the trigger on that outdrive... It is just too good looking to pass up for this boat!!!

Anyway, I got to work on the brackt/shim to mount the outdrive. Decided to make it out of rc aircraft plywood, to give it a bit more strength... Here is where we are at at the moment:

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Angle is about 2 degrees off 90 (with the prop pointing down), but that is close enough, I think. The outdrive should allow me to compensate for that.

Used the template to calculate the size. Left it just a tad oversized just in case (will make final adjustments once the outdrive arrives)

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I intend to give it a coat of fiberglass and resin, but I need to size it first, so I need to wait for the outdrive now... The I will epoxy it in place. As far as color, since I am out of black, I will most likely paint it white (already got too much read around, and silver makes all the imperfections visible!).

[jfrabat]

IT'S CHRISTMAS DAY!!!! And apparently, I have been a good (corona virus lockout) boy! Because I GOT PRESENTS!!!

A package arrived today with my TFL Out-drive and some other goodies!

So, got to work, and made the whole in the transom and the adapter to bring it closer to perpendicular to the keel:

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It may be a little deeper than what I wanted, but I think it will work nicely.

I also received the vinyl cut letters with the name of the boat. And the perfect name in this case!

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I still need to put the side Cigarette Racing side water-slide stickers on, but I will do that after painting the bottom of the hull (it is white, but it needs another coat and I ran out of white; it should be here tomorrow, though).

Anyway, I still need to seal the newly made hole with resin (and maybe a bit of Fiberglass, though I do not want to have to redo the paintwork, so I will need to figure something out; maybe masking will work, not sure...) and fiberglass and paint the adapter, then glue it on the back and mount the out-drive. I also got my cooling parts in today, so the keel pickup (a double pickup) will go in along with a dual exhaust anodized in red to match the outidrive. After than, trim tabs go in along with the servo, receiver, ESC and battery tray. I also got thumbscrews for the rear of the hatch in machined aluminum, which should look nice.

[Jesse J]

Looking good, can you add a photo of the whole boat showing the drive?
I’ll be interested to see how she drives!

[jfrabat]

Looking good, can you add a photo of the whole boat showing the drive?
I?ll be interested to see how she drives!

You mean like this? Mind you, the drive is just placed there; it is not yet mounted...

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I also made the hole for the water intake and water exhaust.

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And the white paint FINALLY arrived, so I will get to do some painting now...

[Jesse J]

Man, that looks great! Yes that’s what I was missing!

[jfrabat]

I am a bit worried, though... I did a balance check today, and it is a bit tail heavy. Center of gravity is about half an inch back from the 33% spot. And that is with the battery and ESC as far forward as I can move them (and not so realistic considering I need to account for the water cooling hose at the end of the ESC!), and without the trim tabs in place. I could move the battery a bit further forward, but that would mean (1) that I need to remove part of a bulhead and some flotation foam, and (2) the ESC would need to move back anyway because now the battery will be centered in the boat and the ESC would not fit well (not to mention it will be difficult to work the battery strap!).

But here is the catch, though; because my transom is angled, the bottom of the hull is half an inch forward of my 0 base. So I might be JUST right if I measure it like that. Of course, if I measure the hull from the bottom most forward point, then the 33% spot moves forward as well, so that means I am even MORE heave on the rear end...

CG.jpg

Current center of gravity is where the circular CG logo is; that is reality. Actual CG should be somewhere inside the box to the front (depending on where I measure the hull at).

If I understand correctly, you measure from the rearmost part, right? That is how I balanced the cat, so I hope so...

Recommendations? Do I take out some flotation foam and rework the bulkhead?

[Jesse J]

Don’t worry. Don’t do anything until you test it.
I have found many boats like 30% and some even farther back.
Give a try and let’s see what she wants before doing anything drastic.

[jfrabat]

Don’t worry. Don’t do anything until you test it.
I have found many boats like 30% and some even farther back.
Give a try and let’s see what she wants before doing anything drastic.

I was calculating at 33%, which is 8" from the rear. But if it is 30%, then it is 7.2" from the rear, and I am at 7.5" now (considering the top of the hull; considering the bottom of the transom, everything changes!).

Now the issue that came up was with the clear coat. Yesterday I got my white and clear (both Rustoleum brand, both the same series of paint). I painted the last coat of white, and it came out beautifully! Today I clearcoated the whole boat, mostly to protect the stickers, but also to give the black some additional shine and the whole paint some additional protection. But in the white, this happened:

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Now I am going to have to sand the white down again and repaint... What a PITA!!! I am seriously considering just sanding out that leaving it like that! Ugh!

[Jesse J]

Good ole rustoleum! I hate that sh...

[Jesse J]

Krylon or Duplicolor automotive rattle cans are what I use.

[jfrabat]

Some more progress... transom wedge (angle corrector, bracket, whatever you want to call it) is in, and outdrive and motor are installed along with all cooling lines.

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This gives you an idea of the prop location in regards to the hull... I think it worked out rather well!

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And for my friend @Jesse J, here are the full body shots:

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Pending: decide if to go with the 150A ESC (which is a tight squeeze, and the bullet connectors would have to be replaced for smaller ones) or go with a smaller ~60A ESC, install battery tray (worried about this one in regards to balance; it may need to be moved forward), and velcro receiver in place. Oh, and seal and paint the rear of the hatch (thumbscrew hole was made yesterday, and it is still in raw wood).

[jfrabat]

Just noticed I never did post a pic of the hatch thumbscrew... Here it is.

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I put some thin silicone between the outdrive and the hull to avoid water coming in. You can see a bit squeezing out in the pic...

Here is how things look inside (battery is not in, but you can see the tray, not yet glued in):

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I still need to switch the servo arm...

Jesse, do you use both sides of the drive for steering? I was thinking of using only 1...