Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: Andy M on February 21, 2022, 09:40:45 pm
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I have mentioned this outboard on a couple of posts already.
I thought it deserves a post of its own,
it seems to work, I have only tested it in the bath so far, but holding the boat must be loading it more than if it was free running. I am hoping it holds together, with the aid of my modifications, additions and reinforcements. I hope to try an open water test soon.
I have printed it in PLA, I imagine abs would be better.
The print includes bevel gears, but I decided right away to use brass gears instead.
Print also includes a left and right hand set of props, supposed to fit onto a flat on the shaft with a steel flat bit, I ditched these too and used an m4 threaded 4mm propshaft section instead, with a 35mm 2 blade prop.
It has 3 bearings, one each end of propshaft and one just above the motor side bevel gear. A solid coupling is used to connect 4mm stainless driveshaft to the motor.
The print has a watercooled motor mount, mine leaked, but I sealed it carefully with a couple of coats of superglue, excess being wiped off very quickly. A light sand on the inside and my motor slid in nicely.
The original designer had used a water pump, I used a waterscoop instead, it goes up through the leg and through the motor mount. I bent a bit of snake outer to its final bendy shape by heating it and using paper stick type cotton bud with one bud cut off up the tubing as a cheap bending 'spring' to stop it flattening out. It goes in the back of the leg and has to miss the propshaft, but theres ample room.
The silicone tube to the waterjacket had to have a spring put up the middle to keep it from folding on the 90 degree bend.
I am going to detail the mods and reinforcements I have added if anyone fancies trying one.
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The motor I am using is a 4 pole 2838 4500kv. It was midway down the kv range of the motors on the specification sheet that came with the motor.
It has loads of power mounted in my Sea Rover, I am using same prop on my outboard so should be similar thrust, if not the same, maybe a bit down due to drag of lower casing.
Still produces bath emptying amounts of thrust. 😁
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Here is a pic of the other outboard on thingiverse, it has a few different bits for different styles.
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Some background, a video and some dimensions
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Here is a video showing my Sea Rover, using same motor and prop and a 3s pack.
My bath test of the outboard was only on 2s pack and it was still very impressive.
https://youtube.com/shorts/k6gPbSjp4gk?feature=share
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Really interesting post.
The photo of the two other outboards are my builds. They use the Open Outboard Motor Mark II design from Christian Pomeroy's Thingiverse.
I personally prefer the open version that is a bit like a Seagull. The first one I built used a 1400kv motor and printed gears. It works very well but is a little over powered. I have built one with a 1000kv motor and its great, but still a bit powerful for a Seagull. I have just received some 930kv motors so that will be my next build.
Look forward to seeing what modifications you do.
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I have had a seagull so I will definately be printing one, and probably the other one too.
I am going to make a few tiny changes on my next version of this one, first of all, the anti cavitation plate as printed, has 2 weak tabs to bolt it on, and its too small. If these tabs snap off, it leaves the lower gearcase screws loose, so I am ditching the printed plate bit and doing a completely new 2mm plasticard one the same size as my enlarged version on my first outboard, welded to the midsection, exactly where it was but not using gearcase bolts and weak tabs. I reinforced these on my mk 1 version so they should be ok. Hopefully. Need to get a test happening soon on open water. Need to fix the hole in my inflatable dinghy soon, I want to take it just in case I need to rescue my boat.
I do have a good few ideas I want to try on these outboards, I think they have good potential. I even thought about scaling up to 150%, using 6mm shafts and associated scaled up hardware, the bearings are available if I try it, and not much dearer.
I think it is worth sticking with these, I printed a couple of extra sets of parts to experiment with and modify. I have one more set of hardware ordered, but it can easily be transferred into a different outboard if I want.
I love the extra potential boat builds that are opened up by having an outboard. It is so easy to swap between hulls.
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Really interesting on the modifications for the anti cavitation plate, having looked at a number of 3D printed outboards that is a common weakness. The larger plate on the outboard with the cowling is only held in place by one bolt, threaded into the plastic, so I am not holding out huge hopes for it surviving long term.
The other issue I hit with my builds was that the instructions suggest replacing the motor shaft with a 3mm shaft and shimming it. This didn't work for me as the original shaft was 3.175mm and it caused some vibration issues. I have replaced the 3mm shaft with a 1/8 inch (3.175mm) brass shaft and machined the lower end to 3mm for the bearing and gears, seems to work a treat. In fact, it got another 3 hours use today, with a good hour of that being by a 9 year old with a throttle heavy finger.
I have just received the nylon push fit bevel gears so my next build will be with them, rather than 3D printed gears, fingers crossed they will work and be an improvement.
I agree with you, since I built the outboard I have been looking at building a whole variety of boats I would never have considered before. I think a working, easy to build outboard could spawn a raft of interesting model boats.
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All commercially available ones have been expensive. Hopefully this one will be reliable as well as being relatively cheap.
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The motor I am using is a 4 pole 2838 4500kv........................
Andy
Are you sure about the 4500kv. With a 3S 11.1v supply that would be nearly 50,000rpm!
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Its all I have, I am just going to run 2s,it never broke apart at full beans on 2s in the bath.
I did run 3s on my Sea Rover using same motor and prop, but it is a very solid mount for all the hardware, not sure if my outboard is up to that.....reinforcements or not.
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Some background, a video and some dimensions
https://youtu.be/fYpT2TCFHKk
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Awesome, I have a re-awakened love for outboards having started experimenting with this one.
Scaled up Keil Kraft Cresta?
I have been brainstorming about mods to the outboard and new project too.
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Andy
Are you sure about the 4500kv. With a 3S 11.1v supply that would be nearly 50,000rpm!
I was wondering if you can calculate if the motor is overloaded with a 35mm prop? It had no prop info.
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I was wondering if you can calculate if the motor is overloaded with a 35mm prop? It had no prop info.
4500kvm is WAY too much
using an ancient windows app called FECalc (fast electric calculator) I have no idea how accurate this is... but...
using a motor in its database that is 4500kvm, and 3 cell 2100mah lipo, and a 35mm octura x series prop...
under load:
31000+ rpm
139 amps
7.85 volts
1000+ watts
43 mph
55 second run time
dropping to a 2200kv motor and 3 cell 2100mah lipo with the same 35mm prop:
under load
20,000 rpm
37 amps
10.22 volts
384 watts
3.5 minutes run time
28 mph
dropping to a 1100kv motor:
12000 rpm
7.26 amps
10.93 volts
80 watts
17.5 minutes run time
17.5 mph
if you want me to run those numbers with a different size prop, let me know.
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I will be running 2s, I dont have any lower kv motors apart from aircraft ones, aircooled.
So I really have to just stick with my 4500 ones at the moment and hope finances improve enough to invest in lower kv motors.
I ran the same motor, esc and prop in my Sea Rover and it wasnt way too much, it was rapid but nothing extreme and that was trying it on 3s.
It has a standard propshaft setup, I wont subject my plastic outboard to 3s.
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the Fast Electric Calculator has a "Prop Wizard" function. given a specific motor and battery combo, it will try to find the "best" prop for that setup... using your 4500kvm and 2s lipo, it recommended an octura x430 30mm prop. It only knows about the props in its database, and those are all racing props, so take its advice as you will.
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Here is the prop I used on the Sea Rover on 3s, 35mm diameter, not quite an x type.
I was running it on a river so never kept it full throttle for more than a few seconds, the esc and motor were quite warmish hot,
I had no cooling on the motor or esc at that point. The outboard now has its own cooling system, which seems to pump water fine.
The Sea Rover still has the other motor of the pair I have. It will be getting a copper coil on the motor and I have already converted the esc to watercooling.
I was thinking about the amps, I ran it on 3s, with a 35amp esc, would that not have popped really quick or have I been incredibly lucky to stop when I did?
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I have to withdraw what I said about the outboard design needing reinforcing, after trying a new nozzle, different PLA and different heat settings, I have managed to produce outboard bits that I have 100% more confidence in.
Due to managing to produce very tough and usable bits, I am going to skip showing the reinforcing stage that I did on the Mark 1.
Only thing is, I dont see much point in continuing with completing a second outboard using the red, weak prints and having to reinforce them.
They do show up better in photos than my tough black ones, so I am showing all the parts I use in red just so the details show up better.
Starting at the gearcase, this has a bearing seat each end, these take 4mm id, 10mm od and 4mm thick flanged bearings. 3 bearings are used in the outboard, the other one being above the bevel gear in the bottom end of the midsection/leg?
The gearcase has screwholes fore and aft for bolting it to the midsection, which has recesses to take 2 m3 nuts.
I bought an assortment of allen bolts, nuts and washer in m2, m3 and m4. I was only after the m3 sizes but it was cheaper than buying them as batches of 5 or 10 of one size. Several lengths of bolt are required
The outboard uses only m3's, some of mine were too long, so you may see up to 3 washers in places on it. Or extra bits of bolts sticking out.
I went for steel bolts, I can get stainless ones in exact sizes later.
Onto the top of the midsection goes the cooler mount, this bolts on with 2 of the the aforementioned '3 washer-ised' bolts into captive nuts in the midsection
It has a clamp that takes another bolt and nut to tighten onto the watercooled engine mount. The mount/cooler has spiral channel running through it, when I was printing it in red, I monitored the printing of this bit very carefully, worried about any stringing blocking the channel, but it was printing very cleanly with no little blips or any strings.
The black bits I have been printing do have stringing, but it is completely extra to the print, once it is pulled off, the print is perfect below. My priner has printed miles of filament, the extruder is quite worn and might not be retracting properly. Thats my theory, I will test it when I get a new bit.
For now though, I wouldnt print the cooler in black, due to the stringing, so I am going to use my original, sealed with superglue, one that is in Mk 1, and seal another red cooler in the same manner.
I have 2 of the brushless motors, so I may as well print 2 outboards.
I have been looking for lower kv motors in this size, 28mm diam, but I haven't seen any at 1100kv.
Anyway, the hood/lid/cowling clips onto the motor cooler mount plate. A small weak clip holds one end, it isnt under any load unless you dont feed it in carefully. I intend to reinforce this with pla or replace this clip system with a metal version.
I made up new anti cavitation plates from 2mm plasticard, these will glue to the midsection instead of flimsy brackets on the original printed version which was too small anyway.
Thats pretty much it for the actual outboard, I will get to the mounting brackets later and some more modifications.
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the Fast Electric Calculator has a "Prop Wizard" function. given a specific motor and battery combo, it will try to find the "best" prop for that setup... using your 4500kvm and 2s lipo, it recommended an octura x430 30mm prop. It only knows about the props in its database, and those are all racing props, so take its advice as you will.
is this the site you mean for the calculator? May be of use if so! Thanks...
https://www.radiocontrolinfo.com/rci-fe-boat-calc/
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Any chance of a calculation using 2s and a 25mm prop?
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can you post pics and dimensions (diameter, length, diameter of shaft) of the brushless motors? i might be able to help you find some lower KV ones.
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is this the site you mean for the calculator? May be of use if so! Thanks...
https://www.radiocontrolinfo.com/rci-fe-boat-calc/
that site is A fe calculator, but the version i have is actually a windows program, and the "database" of information is an editable text file, so i have added quite a few motors whose info i have found, and quite a few propellers to the data that is available on the website.
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Any chance of a calculation using 2s and a 25mm prop?
using the same 4500kv motor on 2s 2100 mah lipo with a 27mm prop (smallest i have in my database)
29000 rpm
41.26 amps
6.87 volts
283 watts
3.13 minutes run time
31.24 mph
2200kv motor on 2s 2100 with a 27mm prop
15800 rpm
8.45 amps
7.29 volts
61.61 watts
15 minutes run time
16.86 mph
(just to see, i went ahead and ran the 2s 27mm on the 1200kv motor)
dropping to a 1100kv motor:
8000 rpm
1.49 amps
7.38 volts
11 watts
86 minutes run time
9.19 mph
seriously, it looks like dropping from your 4500kv motor to even a 2200kv motor would do wonders for your amp draw and run time.
and yes, i would guess that you are playing russian roulette with your 40amp esc
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Thanks, the motor is 28mm diameter, the outboard can take a motor up to 45mm long, more if you leave the cowling off, or make up a deeper cowling. Mine is 38mm long.
I have already bought 25mm props,
The esc says 35, so its probably 25!
Anyway, I dont plan on even using full throttle now I know some numbers.....
If it is 35amp, I can probably run short bursts of 3/4 throttle on the 25mm props. I am planning on transferring the mechanics into a tough black shell soon, or do I just go ahead and test my reinforced weaker print anyway? It is ready for testing, but I am not.
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would this work?
https://www.ebay.com/itm/284420811429?hash=item4238cd2aa5:g:A6UAAOSwISthI1NX
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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......
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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.
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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.
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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.
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That looks great. :-))
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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.
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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.
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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
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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. 😁
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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.
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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
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https://www.youtube.com/watch?v=54bb9zpDdZU (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!
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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.
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Must be a cost saving exercise why so many motor manufacturers supply such short leads.
Regards Ian.
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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.
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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
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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.
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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?
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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
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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😁)
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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
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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.!! O0
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I will remove the red wire before I try it again.
Better to be safe.
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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
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Cool Andy.
Fingers crossed its an easy fix and you can give it another run.
Well done Andy.
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I stripped the outboards and filed flats on the shafts and loctited the grubscrews in.
I have still to test the motors on the water, hopefully soon.
I have also done a bit more on the outdrive, I added more pla to the areas around the holes for the fixing bolts on the upper and lower gearcases. These areas are fairly thin, and the only bits holding the gearcases on so I beefed them up, a standard one is shown for comparison.
I have pretty much finished the outdrive leg apart from shafts, gears etc.
I will be moving onto doing these next, and then the motor mount for inside the boat. This will be bolted through the transom and outdrive leg to maintain alignment. I have ply sandwiched together to the same thickness as the transom and will be using this for building the motor mount onto, to get shaft length correct. I am also fitting a flexible coupling, so the motor needs to go forward a bit.
I have it mostly worked out in my head, just got to convert it into bits of wood now.
The outdrive looks not bad at all beside the Javelin, I wont properly know how it will look until I strip off all the outboard bracketry and fit it.
I will be keeping the outboards on until I get some time with the boat on the water, so it might be a while.
Definately moving forward though.