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[tsenecal]

would this work?

https://www.ebay.com/itm/284420811429?hash=item4238cd2aa5:g:A6UAAOSwISthI1NX

[Andy M]

Hi, I had a look, but no option for shipping to uk. I really have to stick to what I have just now, my budget is pretty maxed out with my Javelin builds, I am hoping my 25mm props, 7.4v, sympathetic use of throttle and careful monitoring for heat will keep it all working.
I have a 1700kv motor, but it is an outrunner, I had planned to get round its cooling issue, not getting any air, by putting it in the boat with a cooling fan and building an outdrive using selected parts of the outboard, ie the bits with bearings and shafts. I have already printed the parts I need, just waiting on some bearings and gears.... And a final plan of how I am going to do it, the main bits are perfect, just have to be held together and attached to the boat. It would work perfectly with a big blob of hot glue encasing everything.... But I want it looking fairly good. The outdrive has to have the rudder on it too.
I will post some pictures once I start fitting bits together.
Hoping to get a black printed outboard fitted out with mechanics today... or tomorrow😁
No rush.
Cheers for finding the motor, much appreciated, I will get one as soon as I can, these outboards deserve the proper stuff, to me, it is the only way to go, commercial stuff is way too expensive and doesnt usually look like a real outboard, or have any tinkerability.


These are a little side project for me, the filament costs are low, the bearings and gears can be swapped around if you wanted to print different coloured ones, just more possibilities.


Often in the past, browsing through my plans catalogue, I would find something I really liked, but it was for outboard. Now, a whole new branch of boat designs is available.
I am even putting one on a Javelin, which is an inboard design.
Hopefully the new black prints will be plenty strong, they certainly feel much stronger, time will tell......

[Andy M]

I stripped my outboard, ready to fit some of the bits into my black casings.
It is a good opportunity to show the internals, I will be replacing the brass bevel gears with bigger steel versions, apart from them, I will be using the parts as shown.
I need to make up the watercooling tube that runs up the inside of the leg. I hope to make it better than the one shown, although it worked fine.
Once it is all in the black casings, I will feel more confident  for testing, also the bigger gears have more of a chance of surviving than the little brass ones. I may use them in the seagull type outboard.

[Andy M]

I started on getting the black casings ready to fit the mechanics into.
 One of the photos shows the brass 0.5 modulus gears beside the new 0.8 modulus steel gears. These look a bit more up to the job, I will do some measuring and maybe see if the gears could be bigger again. Or If I could get a 2:1 reduction set of bevel gears in there, turning my 4500kv motor into a 2250.
 Anyway, I fitted bearings in the gearcase, these were a good fit, not requiring any fixing, I might still use a couple of tiny drips of superglue at the edge of the flange on the bearings. Just to make sure the outers dont spin.
 Next up was the bearing in the centre section, it was slightly loose, so I built up a few layers of superglue, wiping off any excess that might interfere with the bearing. I am letting this set for ages to make sure my bearing wont get white fogged and maybe jam up.
 I have shown pics of a gearcase section that I printed with the bottom of it missing. It has holes in it to allow the mesh of the gears to be seen and a slot to tighten up the bevel gear on the motor side of things. The bevel gear and collets on the propshaft can be tightened up through the missing bottom.
 This is really a must have part for me, otherwise you are just guessing how they mesh.
 I will set up the gear mesh in the 'jig'
 Probably leaving it assembled as a reference piece, I will assemble the black gearcase parts to replicate it.
I did think about transferring those parts into the black casing, but it would only be an estimated position from memory of the gear. Its a bit tight to get in for vernier measurement.
 If I have the perfectly meshed jig piece to look at, I can set the gear pretty accurately by comparison.
 I can also use it to set the motor gear height on any new outboard.
 I need to wait till my new gears arrive before I can manage this......
 So, onto the midsection modification.
 I used the watercooler, mounting plate and motor assembly to accurately mark the hole for the watercooling tube in a black mounting plate.
 I then used cotton buds with one end cut off, as poor mans bending springs up the inside of a bit of control snake outer, and heated and bent it to the weird shape shown.
 The black plate allowed me to align the tube properly and see that it missed the driveshaft, before fixing it permanently in place with superglue and balsa dust.
 The red plate, cooler and motor assembly will be used, as they are ready to go, and the cooler is superglued to the mount plate to prevent rotation, I didnt trust the clamp on its own.
 I will report more and put up more pictures once I get the bearing in the bottom of the leg seating nicely and some assembly done. I will be held up by not having just one more gear, ah well, got other ideas I can get on with in a similar area.

[Andy M]

I still haven't fitted the gear and collets in the gearcase, but I thought I would see how the outboard looks with my new 25mm prop. Looks proper job, well impressed. I had to add another nut as my propshaft threaded bit was too long. It looks as if it will be better there, further behind the casing.

[CarlC]

That looks great.

[Andy M]

Thanks.
My bevel gears arrived, so I assembled the gearcase. I have spot glued the bearings in place so they cant spin. I used brass spacer washers between bearings and the collets. These were taken from a propshaft I bought to make my outdrive.
I was able to use verniers to set the gear in the exact same place as the red jig.
I gave the gears etc a thin coating of grease 😁 to try keep some water out. Two screws removes the gearcase for emptying anyway.
A bath test confirms it is running nicely.
Very very nicely. The grease has quietened it a bit
No heat build up in motor or esc from bath testing, will keep checking when I get it on open water.
I added a brace between leg and anti cavitation plate the painted the plate etc black. Brass prop stands out nicely. Was too windy for testing today, I can wait.

[Andy M]

It was a nice day but a bit windy, so I wasnt planning on taking the hydro/outboard for testing.
 Then the wind died down a bit, so I took my boat for testing, with my son as cameraman.
 Loch Lomond is fairly close so I went to Balmaha, it was a  beautiful evening , flat calm, I know the boatyard owner and he was my standby emergency recovery plan if anything happened to the boat.
 So, in the water a few low speed turns to see if it would turn ok, incredible turning circle so I went for higher speed.... It was sitting fairly nose high with sponsons barely touching the water, looked as if it wanted to go much faster, maybe wrong outboard angle? Anyway, I ended up doing a tight turn with gradually more throttle, then it flipped over! Waaaaah.
 My emergency rescue plan was scuppered when said boatyard owner could not be found, or a stone or rope or anything. It was still functioning, so I tried full throttle with the prop in the air and it started moving, barely perceptible but definately edging closer. Then it stopped. Waaaaah.
 It was drifting near to a work boat, I figured it was my last chance and I climbed the fence and went along the jetty, into the workboat grabbed my boat and back out, yes! Thought it was drifting away, ready for shorting out. It is depron so no chance of sinking.
 I am pretty sure the motor had still been running, I think a grubscrew on a gear may have come loose, or it has stripped all the teeth.
 Main thing was to dry out the radio gear. And my battery, it was dripping.
 I will take the gearcase off for a look soon.
 All in all, I think it was successful, even though I got stupid and flipped it, should have taken my inflatable dinghy just in case, or even a string and weight.
 The outboard was good, the hydro maybe needs a weight shift, pretty difficult, or maybe angle the outboard so it lifts the back up a bit, I have it pointing straight out the back.
 I will definately try that, pretty sure that is the problem.

[ChrisF]

Looking very good Andy. I think you're right about the angle of the outboard. Not such an issue on a traditional planing hull though the prop is usually angled down anyway.

Interesting what you say about spot gluing the bearings in. I was concerned that the ball-race bearings were spinning in my Tamiya Unimog build. Asked on a forum and many replied that it was Ok for the outer part to spin! I had some clear silicone to hand and used that.

Chris

[Andy M]

Thanks
I went to reassemble the outboard but quickly found the motor bearings seized. Oops, forgot to oil them after blasting them out with the airline. I think this is going to have to be a total strip/blast with air/ oil bearings type of machinery.
 There isnt much waterproofing built in, seals would be good but the fit of the gearcase and boltholes will always let water in.
 Seagull engines actually quoted their gearcase lubrication as oil/water emulsion. Lol.
 Anyway, with some 3 in one oil dripped into bearings and left to soak for a while, the motor freed off, I fitted it to the midsection, set up the gear with my jig and prepared to run motor slowly, without gearcase fitted so I was just testing the motor.
 I connected up and tried it, very bad vibration and it cracked the collar off the motor mount and tried to spin.
 The vibration is down to the rigid coupler, it has 4 screws, all in the same plane, and not the tightest bore either so the whole plot can wiggle in the middle. I need to address this. The gearshaft has no bearing where it meets the coupler, so it relies on that for support at that end. I thought about adding a plate in the leg with a bearing, but I hoped that doing it the standard way would work. It did for a while in the boat before it vibrated its grubscrews loose.
 I might make a special request to my engineer friend to see if he can make me a tighter coupling with 3 grubscrews each end, or 4?
 It really needs to be held straight or it will always shake.
While working on the balsa Javelin, I came up with a new idea but using some of the same components (the bits that work😁)
 I have printed 2 outboard lower leg pieces, stopping the print at the exact same height on both, this gave me 2  bits with bearing holders and I welded these together using a 3d pen and tidied/blended it with soldering iron and flat tip.
 The gearcase from outboard fits straight onto either end of this piece, the normal gearcase with prop pointing out the back doesnt need any mods, the one on top needs a hole drilled through the front of it to allow the shaft to go forward to the motor. I used the bearings as guides to carefully drill hole.
 I am waiting on bearings and gears coming before I can proceed with this project.
 Doing it this way means a few things get cured at once. All shafts have 2 bearings on them, and as the motor will be in the boat, it will be dry and also be connected by a flexible coupling this time.
 I have still to figure out attachment to the boat, I have several unused printed bits I might be able to use, I have still to think through this bit of it. I have to make an anti cavitation plate and a strong bit for the rudder, probably with 2mm plasticard laminated to whatever thickness I need, this may be incorporated as part of the mounting system, its all experimental. 😁

[Circlip]

On basically what is a three phase motor, warnings were given about increasing the lengths of the motor wires. Used to have to fit electrolytics between the Esc and motor, has this changed?


  Regards  Ian.

[ChrisF]

Glad you mentioned that Ian. I remember reading sometime ago that you shouldn't really lengthen some wires but couldn't remember which i.e. motor or battery.

I shall make sure the ESC is mounted close to the motor in my builds.

Chris

[Stuw]

https://www.youtube.com/watch?v=54bb9zpDdZU


Well this guy says ok to lengthen ESC to motor wires but not the battery wires.


I don’t know how correct or not he is but he has a few different videos about ESC performance.


My ESC to motor wires need to be lengthened in my Javelin as ESC planned to be in rear, but as my build is not progressing I could always change that if anyone provides definitive info suggesting not a good idea!

[Andy M]

I dont see it making much difference unless you are adding a metre or something, even then I think you would be hard pushed to notice any difference.

[Circlip]

Must be a cost saving exercise why so many motor manufacturers supply such short leads.


  Regards  Ian.

[Circlip]

Just had a scan on American site, Battery to ESC short as possible and electrolytics added in that lead. ESC to motor can be safely lengthened.


  Regards  Ian.

[JimG]

Must be a cost saving exercise why so many motor manufacturers supply such short leads.


  Regards  Ian.

Since most will be produced for electric flight purposes there is no real need for long leads. Most motors , esc and batteries are in close proximity in the nose of the plane. Longer leads will slightly reduce the voltage to the motor and therefore the power.
Jim

[Andy M]

I had a Kyosho convert electric heli years ago, it was supposed to run 9.6v micro battery pack (it was micro back then). I ran it off a 12v motorbike battery with 20 foot leads.
It worked well, but it could only lift the first 8 feet of it off the ground. It gave me much more time to practice, even if a bit hampered by the trailing cables.

[Andy M]

I have now finished my second outboard, I had to re-think the hood/cover fixing method, the original method used flimsy fittings. I added extra pla to the front 'corners' of the hood with a 3d pen and smoothed off with a soldering iron. 2 small screws now hold it on nicely.
 At the rear, I replaced the original hoop with a paperclip one.
 I also changed the spring in the water feed tube on original mk1, it had rusted. I made up 2 new 'springs' from brass wire, formed round a drill bit, so both have new non rust anti fold tube liner coils.
I have one outboard on my balsa Javelin just now (ready for testing now😁😁)
 I have made provision for fitting both my outboards.
I was wondering if this diagram I found online is correct?

[JimG]

It looks like you are powering the receiver from the esc. If so then remove the red wire from one of the esc plugs, fold it back and tape it to the wire behind the plug. Only one esc should be powering the Rx. Some will just cut the red wire but removing it from the plug allows you to refit it if the esc is  reused later.
Jim

[Andy M]

Hi Jim, I decided that as both esc's are powered by the same battery, it should be ok to leave both rx plugs intact....... And it seems to work fine. I tried the setup last night with no problems. Cheers anyway. If I get any problems I can always take one red wire out. (unless its already fried, that is😁)

[JimG]

Andy, what can be the problem is that the output voltage from the BECs in the esc may not be exactly the same. This can lead to the BEC in one of them becoming hotter and in some cases overheating and failing. This could then lead to the other one also having problems and eventually no Rx power. Better to remove one of the wires now to forestall any possible problems. It might work OK for you if you have two esc which match each other well but best not to take the risk.
Jim

[Backerther]

I do quite agree to Jim's comment.
I do think two route(different voltages) power supplies with one Rx may cause some kind of trouble in the future.
Voltages between the ESCs may be possibly and exactly different each other even if they are the same type of ESCs.
I never adopt such two way power supplies with one Rx to save my boat if she should use two ESCs.
One route power supply seems much safer and sufficient for the boat which will normally remotely be controlled on the water where is away from you.!!

[Andy M]

I will remove the red wire before I try it again.
Better to be safe.

[Andy M]

I have now tested the balsa Javelin with twin outboards, something came loose before I got to full throttle. I think a grubscrew has loosened. I need to file flats on the shafts and loctite the grubscrews.
 I was able to make it back to shore on one outboard, fitting twin outboards to start with has paid off! No wading into freezing water to rescue it.
 Video of short but promising test run here
 
https://youtu.be/a3AgBR7bfMc