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Thread: New scratch build 24" mono

  1. #31
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    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.
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  2. #32
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    OK, looked at your videos and pictures. And also did a lot of measuring... Lets take a look at the measuring first:

    20200509-105959.jpg

    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.

    20200509_112401.jpg

    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.

    20200509_112653.jpg

    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!!!

    20200509_110033.jpg

    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.

  3. #33
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    Just to be on the safe side, I double checked with the side drawing...

    20200509_114544.jpg

    Conclusion: I NEED THAT DRIVE!

  4. #34
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    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:

    20200509_165214.jpg 20200509_165220.jpg

    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)

    20200509_171125.jpg

    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!).

  5. #35
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    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:

    20200519_173717.jpg

    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!

    20200519_173729.jpg

    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.

  6. #36
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    Looking good, can you add a photo of the whole boat showing the drive?
    I’ll be interested to see how she drives!
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  7. #37
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    Quote Originally Posted by Jesse J View Post
    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...

    20200520_111014.jpg 20200520_111023.jpg 20200520_111053.jpg

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

    20200520_105850.jpg 20200520_105937.jpg

    And the white paint FINALLY arrived, so I will get to do some painting now...
    Last edited by jfrabat; 05-20-2020 at 12:14 PM.

  8. #38
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    Man, that looks great! Yes that’s what I was missing!
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  9. #39
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    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?

  10. #40
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    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.
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  11. #41
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    Quote Originally Posted by Jesse J View Post
    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:

    20200521_095807.jpg

    20200521_095812.jpg

    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!

  12. #42
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    Good ole rustoleum! I hate that sh...
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  13. #43
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    Krylon or Duplicolor automotive rattle cans are what I use.
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  14. #44
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    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.

    20200522_141727.jpg 20200522_141841.jpg

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

    20200522_141904.jpg

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

    20200522_141807.jpg 20200522_141814.jpg

    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).

  15. #45
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    Just noticed I never did post a pic of the hatch thumbscrew... Here it is.

    20200522_143038.jpg

    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):

    20200522-161157.jpg

    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...
    Last edited by jfrabat; 05-22-2020 at 05:20 PM.

  16. #46
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    Well, did a pool flotation test... I think the debate is over. Battery needs to be moved forward. Either that or stick the ESC forward, but I need weight forward... She floats with her but almost submerged.

    20200522_163952.jpg

    I also have a water leak somewhere (I think it is coming from the trim tabs). I have to get rid of that pronto!

  17. #47
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    Proceeded to carve out some flotation foam from the front. I did not need to touch any bulkhead, which is good.

    ESC will now go to the front (there is still some foam over the ESC):

    20200522-172659.jpg

    Now battery will be centered, and servo moved slightly back for better movement:

    20200522-172645.jpg

    Overall, CG moved less than half an inch, but it makes a WORLD of difference in flotation stance

    BEFORE:

    20200522_163952.jpg

    AFTER:

    20200522_172225.jpg

    Like this I am willing to give it a shot.

    Now, one question: is it really bad if I make extensions to the ESC to motor cables? Otherwise I will need to disconnect them every time I take out the battery... Also, I could make them 6mm bullets on one side and 3.5 in the other and avoid any cutting of cables. But I do not know if a couple of inches here will result in more resistance or something along those lines (I doubt this motor will ask too much of this ESC, though, so, for this application, I could be OK, I guess!)

  18. #48
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    Alternating current in brushless motors is less affected by longer wires. Try to stay under 6”, 8” at most.
    Where is center of gravity? Ya that drive is heavy and your boat is narrow.
    I do use both steering arms, but you may be ok with just one.
    Oh, and in case I didn’t emphasize, go very light on thread lock... I had to dremel out a few screws when I went to service the outdrive.

    Did you run yet?
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  19. #49
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    Quote Originally Posted by Jesse J View Post
    Alternating current in brushless motors is less affected by longer wires. Try to stay under 6?, 8? at most.
    I need about 6 inches or so (maybe even less). I also made an extension for the battery (I made it 6mm male/female to XD60, but, OF COURSE, I used the wrong side of the XD60!!! Now I have to resolder!). By the way, the batteries come with XD60 connectors; since this motor is supposed to draw less amps, do I go with that or still switch to 6mm connectors? I take it that if the motors have 3.5" bullet connectors, XD60 should be OK, right? I was planning on keeping the XD60's...

    Quote Originally Posted by Jesse J View Post
    Where is center of gravity? Ya that drive is heavy and your boat is narrow.
    Right now, it is right at the start of the N (right after the I) of QUARANTINE. Moving the ESC to the front only moved it about a quarter inch. I am still behind the 33%, but now by about a quarter inch, and, if I need to, I can push the battery a bit further forward now (I got about one or 2 inches of room before I hit the ESC).

    20200523-154326.jpg

    This is where the ESC is now (this is before I glued the tray in, but it ended up in the same place):

    20200523_123235.jpg

    I know you cannot judge distance from the pic, but the ESC is about 2 inches inside past the bulkhead.

    Quote Originally Posted by Jesse J View Post
    I do use both steering arms, but you may be ok with just one.
    The way I have it set up, I will go with just one. I AM using a 3mm rod with a 20Kg servo (with swivel ball joint on one end and the outdrive's rod connector on the other), so there should not be any issues. Besides, I put the water outlet in the way of the second arm, so if I wanted to install it, I would need to re-drill some holes...

    Quote Originally Posted by Jesse J View Post
    Oh, and in case I didn?t emphasize, go very light on thread lock... I had to dremel out a few screws when I went to service the outdrive.
    Yeah, I will. I still got to open it up and lube it. Have not gotten there yet.

    Quote Originally Posted by Jesse J View Post
    Did you run yet?
    No, it is not finished yet. And we are still in lockdown here, although the parks will open on Tuesday.

    Today I glued in the tray for the ESC (had an extra battery tray that fit just right!), which was a fun endeavor, as that whole tray is in the bulkhead ahead of the hatch. I used a velcro strap to keep the ESC in place, but if I ever need to remove it... well, lets just say I will be entertained for a day or 2!

    I also glued in the battery tray and the servo mount in place. I took all the hardware off and remounted everything to try to fix the leak I had (which was substantial). I used silicone (I have conformal silicone for my electronics) around all the holes in the rear. I also used some gasket material to make a gasket between the outdrive and the mount, as the boat is not perfectly machined. I put some more silicone around that, and I still have a tiny leak, but now it is much more controlled. I located the leak (the outdrive mount), so I will go over it with silicone once more to seal it.

    20200523_125808.jpg

    I still need to make the extension from the ESC to the motor (which I will also use to go from 6mm to 3.5mm bullet connectors, as the ESC comes with 6mm and the motor with 3.5mm, and that way, I do not need to cut anything!), re-solder the XT60 (the right one this time!), and make the hole for the steering rod and install that and the boot (which will going into the boat as opposed to going out, like I have it on my cat). I need to seal and paint the rear hatch (I made the hole for the thumbscrew), and I also need to velcro the receiver to the hull, but that takes 2 seconds. But it is almost there now!

    One last pic showing off the hardware!

    20200523-154332.jpg

  20. #50
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    A bit more progress... Servo is now connected to the outdrive.

    20200524_135657.jpg 20200524_135710.jpg 20200524_135704.jpg

    The rod is still hitting the top of the hole when I turn right, so I have a little finessing to do still. But it is all in now. Also did a pool test (now with the boot on and the silicone in place) and I got no leaks.

    20200524_135742.jpg

    I just noticed it looks like water inside, but that is actually resin... No water got in at all.

  21. #51
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    OK, I fixed the rod rubbing issue, but I need to strengthen the servo mount hold. The servo is strong enough to rip the epoxy (when I had rubbing), and it did. I am thinking of epoxying supports like this:

    20200524-174845.jpg

    The good news is that the outdrive is steering well... I made a video in my pool... I still got no power (until I make the ESC to motor extensions), but I need to wait for the bullet connectors to arrive first.

  22. #52
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    Balsa might not be strongest option, you have any basswood or ply you could use?
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  23. #53
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    Not really. I have some 3/8 (might be 1/4, not sure) ply, I could try that...

  24. #54
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    Servo mount was epoxyed back un place and plywood additional supports have been added. Not my prettiest job, but it should hold!

  25. #55
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    Here is the picture:

    20200525-230331.jpg

    And here is a video of it working this morning:

    https://youtu.be/xTAf_aOtN1g

    Looks like the correction worked; the servo is stable.

  26. #56
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    Bullet connectors finally arrived... And it turns out, either the motor does NOT come with 3.5mm, or I got sent the wrong size in the 3.5mm package. Because, most certainly, these bullet connectors are smaller than what is on the boat (actually, they are the same size as what comes in my Aquacraft Minimono). Anyway, I looked in my drone stash, and I had 3 female connectors of the right size! So we are READY TO RUMBLE!

    These are the extensions I made:

    20200604_152152.jpg

    And this is how they look in place (or how the DON'T!):

    20200604_152215.jpg

    Of course, I HAD to try the boat out in the pool, and this is where I screwed up... My son was filming me as I made a hole in the vinyl pool! You can see that here:

    https://youtu.be/pLT-9dNeR2k

    Oooops! Boat is fine, by the way... The pool took all the damage.

    As far as speed, I think acceleration is significantly slower than the cat, but I am hoping it will pick up speed in long runs. As for turn fins, I think I can get without, but we will see once we actually run the thing for real!
    Last edited by jfrabat; 06-04-2020 at 05:18 PM.

  27. #57
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    By the way, I am seriously thinking getting a new radio for this boat. I am using the same Tactic basic radio that cam with the Minimono, but I think I am going to need something a bit more sophisticated for this. For instance, something that (1) records endpoints, (2) remembers channel reversals, and (3) has an exponential function, because this boat gets a bit squirrely once on plane with the steering. I was planning this boat for my son to use, but he is going to have his hands full, I fear!

    I would give him the cat, but that one I think will be too fast for him. But who knows; he may end up driving better than me! LOL!

  28. #58
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    Finally got around to running this bad boy... First off, the boat bobs up and down (see video). I am not sure if it is a balance issue or a driveline angle issue (I am inclined for the latter, but maybe both!). For the run, I pushed the battery as far forward as it would go, so it may be a bit heavy in the front.

    I ran it easy, mostly at around half speed. I did give it a couple of runs at full throttle, but was mostly running at half throttle. At the end, the boat would not turn (it was locked into to a left handed turn). Then, I lost throttle as well (you could hear the motor, but no action from the boat). I figured I had lost my prop, so I waited for the boat to float to shore.

    Once we recovered, I noticed we did have a prop. The issue (I would find out when I got home) was actually worse; it seems Steven was right to warn against using a 4S. In my first run, I stripped the gears on the drive!

    20200606_122312.jpg

    Looking deeply back at home at the problem, the issue is that the gear was not meshed properly. So that is something I will have to take care of once I get the new shafts for it, which I need to take care of now (edit: Already ordered from OSE!)... Oh, and the cause of the left turn lock? I forgot to put Loctite on the bottom bolt of the direction system (it has two bolts, top and bottom; bottom one is gone!). Good news is that at least the cat ran like a dream!

    Here is the video of that first run, so you can give me some advice on how to fix the bouncing issue:

    https://youtu.be/ewgDD9TAwEo

    What is my issue? Drive angle? Center of gravity too far back? Or too far forward? Or a combination of these?
    Last edited by jfrabat; 06-06-2020 at 09:59 PM.

  29. #59
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    Hey there, looks like your video is private.. can’t watch it. Try changing to public.
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  30. #60
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    Try it now

    Last edited by jfrabat; 06-07-2020 at 01:27 PM.

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