Making a bit of a start on my stretched Stiletto (more a Stilapier) at the moment, as it had been put aside while I had a play with a surface drive to fit to it, if I could get one working (see under surface drive experiment, in forum). I've shelved that idea till I can find a suitable universal for it, and have decided to use a modified cable drive instead (see under 'converting a cable drive to a standard drive', in forum) I wanted to settle on the drive type before starting fully, to make installation easier.

The Stiletto has been stretched to 38 1/2" by blowing the A4 sized drawings up to AO paper size. I've left out the usual internal locking structure so as to create more room and ease of access to the internals, instead, the whole cabin will lift off, rather than a few 'lids'. All the new positions have been worked out using top and bottom datum lines (pic 1). The deck camber has been changed but the deck sheer left in. A few other mods will be made as things progress.

I started by cutting out the keel, breast hook and new ply bulkheads, then cut the centers out of the bulkheads notched them for the stringers and reinforced them. I made a new universal building jig (under model framing jig, in forum) to hold everything in place, (right side up and upside down), and set everything up on it. Glued all the bulkheads bar the transom to the keel, (keel has shaft tube slot previously built in by cutting the keel on the appropriate angle, separating the 2 pieces by a shaft tube diam, trenching 2 side plates to suit the shaft tube angle and diam, and gluing/clamping them on using the building jig to hold them flat and straight.

I've made a cut-out for the motor in bulkhead 3, and bent the cable drive to suit. A motor mounting plate will be made later. Cable drive will have a V brace made to suit once the angle has been sorted for prop clearance etc.

Getting hard to find some modelling supplies (namely spruce strips for stringers and balsa) now so there might be some slow patches in the building.

The basic frame (keel and bulkheads) now flipped over, lined up on the jig again, with the necessary bulkheads packed for the deck sheer to keep it all in shape. The bulkheads are clamped to the jig to keep it all solid. Started fitting the bottom stringers, which once planked will make the hull easier to work on while fitting certain internals. Side and gunwale stringers will be done once any internal work (motor, shaft, rudder, floors etc) is done.

The hull has been re designed, as balsa planks and f/glass will be used, rather than ply, making it lighter but needing stringers all round. The original only had chine and gunwale stringers, (the ply replacing the intermediate stringers.) Also, the cabin construction was part of the framing.

Chine stringers now glued in place. Will possibly have balsa top laminations for finishing if needed. I usually leave the stringer notches a bit larger in places to allow for 'flow' alignment. Usually get a few waves in the stringers when re-modelling a hull, (even doing them from a plan) I just pack the gaps later with balsa glued in and trimmed.

You can run the stringers over the frames/bulkheads which will allow water to drain easier (no need for limbers) - runs straight to the transom from anywhere. Good method for open boats with frames, which will be subjected to water inside, as you can leave floorboards in and just tip the boat up to drain. Notching stringers is a probably a bit easier for models, as they don't usually get any water ingress.

I've finished the framing for now, and have started the planking. Started by gluing a 3mmx3mm spruce strip down the center of the keel, to form the 'rebate' for the 2.5mm balsa planking. Next thing was to cut the 100mm wide balsa sheets roughly to shape, and butt join an extra 40mm on to cover the width. Chine stringers were also bevelled to suit the bulkhead/bottom angles

Airplane guys will probably know this, as it's usually a wing sheeting method.

Sheets were joined by 1. butting them up side to side tightly, 2. taping the joint with masking tape pressed down firmly, 3. opening the joint and filling the V with PVA glue, 4. closing it and placing the sheets tape down on a flat surface, 5. wiping off the excess with a damp sponge, 6. weighting the joint along the entire length and leaving it to set thoroughly for about 12 hrs. When dry (test with a sharp modelling knife pricked into the glue) remove the tape and you are ready. Be gentle with it though. Once applied to the frame/cabin etc, you can reinforce the join on the inside with thin ply, glass tape, or cross grain balsa strips. If you are glassing the hull, it's still a good idea to reinforce the join.

Using a liberal bead of balsa glue on all areas, the sheeting on the first side was applied and clamped, and a few pins used in un-clampable areas. Sitting quite nicely so far, (these hulls having developable surfaces, like a lot of older models- ie- no steaming required,) so will probably be attacking the other side tomorrow.

Second side on now,-once set it can be trimmed and flipped over on the jig. Might have to make a few mods to the jig to support it, now the sheets are on.

Hull is now flipped over, levelled and secured to the jig again, using the extension legs on the cross-bars. The keel locating angle blocks have been removed from the base board for the keel to sit flat. Because of the 'rocker' in the hull, a cross-bar is placed at the bow to keep it up.

In this configuration, I can do the chine and mid stringers and deck, but will be doing the motor mount and internal bits before any of that, as it's easier to get at the inside without framing in the way.

Decided to laminate the spruce gunwale stringers to give the frame a bit more stiffness, as it will need moving around a bit before the side center stringers and sheets are fitted later. Also cut a 4mm ply plate for the engine mount to be fitted later. Still easy to fit internal floors etc like it is.

Gunwale stringer completed with 3 laminations of 5mm x 2mm spruce.

Removed the frame from the jig and re-mounted it using the transom clamped to hold it in place. Trimmed the laminated gunwale stringer with the belt sander to get the tops flush with the bulkheads. Trial fitted the shaft for position and glued in the motor mount plate. Also pre bent the side mid stringers (using boiling water run down them, a quick wipe to dry and clamping in place to set. These will be applied after the necessary internal work.

Finding new uses for the framing jig. Using this method to keep the frame from twisting while working on it right side up, and raised up for prop shaft/motor mount work, or while waiting for work to be done. Obviously it's a bit flexible still without the side sheets, and clamping it like this holds it in shape. Just levelled at the transom and clamped (as previously done) but with the addition of 2 front struts. Sighted across the 2 bars to get it all level.

I'm finding the jig is really useful, as you can clamp the model in almost any position, using a combination of the extension legs and cross bars, (also using cross bars for sighting level).
Not much progress at the moment as I've been busy elsewhere, but hopefully will be doing more soon.

Been a while (seems like yesterday) hope everyone's been well, but had important work to catch up on (house, health, cars etc) which delayed progress. Finally got the urge to throw the top side sheets on, (too hot to work outside at the moment) using my jig as a platform to keep everything level. When I get a bit more time, I'll be able to glass the hull, and/or start fitting the motor/cable drive etc.

JB

A bit more progress with the modified cabin being started, and deck ply cut out. Cabin is a bit different to the original, further forward and an inch longer, with larger sharper windows to modernize it a bit. Still more to go on it yet. I usually start with the basic plan for a model, then 'freestyle' it after that and make it my own version.

JB

Deck cutouts done and cabin roof side overhangs sanded off (didn't like them,- something to break). Holes at bottom of front screen filled in as well. Inwales etc to be done yet in the hull for the deck supports.

JB

Inwales and other framing for deck support done, as well as front compartment floor supports. Floor would not fit through the bulkhead so was made foldable so it can be removed if necessary.

JB

A bit more progress, - was busy with displaying my racing dinghy in the Auckland wooden boat festival so haven't made much progress. Marked the deck, made the rudder, and last night glassed the hull. Thought it was an idea to glass the hull now, as the weather is getting cooler and rain finally appearing after months of nothing.

JB

Warm last night, (10.30pm) so decided it was time to throw another heavy coat of resin on, (after some heavy duty sanding of the initial coat rolled through the cloth). levelled off quite well, so I'll give it a few days to set up properly, de-wax again, then attack it with the orbital sander and see how it comes up.

JB

A bit more done now some necessary house maintenance has been completed. Not a lot done but I've been doing some RC plane maintenance as well. Glassed the cabin tops with a fine cloth and polyester resin, rubbed a few coats of varnish stain on the deck, cut glass off the shaft slot and finished lining up the shaft and screwed the motor mount in place. Temporarily trial fitting bits and pieces for balance, and will be making floors to mount everything on later.

Deck will be glued down when everything inside is sorted. Waiting for it to stop raining so I can put the hull on the drill press and drill the rudder tube hole straight. Winter now, so should be getting on with it a bit more.

JB

Knocked up a stand for the boat today using ancient no nails technology (unless you call dowels nails) A bit more fun to do and no holes to fill. Still have some more cutouts to sort for the rudder when it's installed and some padding and staining. Finished with the building jig, so now just needed to have something smaller to sit the boat upright on to work on the inside bits. It will have a stop on the back to go against the transom so the boat will sit down in the correct place every time, and maybe some adjustable side clamps to keep the boat in place.

JB

Stand is finished now, nothing fancy, just serviceable. It has a backstop and slotted side clamps now which secure the model for transport. The clamps work well and will also be handy for holding the boat still while working in the innards. Luckily didn't need any cutouts for the rudder, and it all just fits like I planned it😉

JB

Due to the nasty weather lately, I've been forced indoors, so have managed a bit more progress in the last 2 days. I've sanded the glass on the hull and cabin tops, painted a sealer on the cabin, made a rudder servo tray, a central radio(and other bits) tray, a battery tray and a front compartment tray.

The center and front tray are 'hinged' to fit through the bulkheads etc, then folded out to fit. The front tray is secured with a 'cam' The servo tray fits in through the bulkhead then is turned clockwise to fit in place, (with only 1mm clearance- hence opposite corners angled). I prefer not to glue trays in, and screw them in wherever possible, in case mods or repairs are required later. Lots more to do yet.

JB

Inside of the hull has now been coated with epoxy timber sealer/preservative, as well as the equipment trays, which have been made to be screwed in, fitted and unscrewed ready to be put aside for after painting. The prop cable drive shaft outer now has a strut which bolts through the hull and through ply reinforcing on the inside.

The RX, UBEC and ESC will probably be Velcro'd in, and the water pump screwed on with its' mounts. Most things have now been pre fitted, so just a few things like rudder arm and link to make, and the deck can be glued on, (needs doing before hull painting so edge can be sanded flush with hull). Everything is fitted so it can be removed easily once the deck is on. Spray rails will be glued on , and shaft tube finally glued in before painting the hull.

Cold and wet at the moment, so could be a while.

JB

Another bit of progress, despite having to deal with the neutral line to my house being ripped off by upgrade work being done on the power lines in our street (could have been electrocuted !, cost me $2070 to have a new line installed,- expecting compensation !!) and the connection to the water main in the street failing a week later, and turning my property into a swamp,-(councils' problem to fix)

The cabin and hull now have 2 coats of water based Zinsser 123 sealer applied with a 100x20mm roller. Too wet cold and windy for spraying, but the roller worked well. I use this paint to seal any wax which might remain after glassing, as it can cause spots to appear in acrylic paint. Dries quite quickly and gets a harder finish than normal undercoats or primers but is still good to sand. The Zinsser BIN oil/shellac based sealer is excellent for this also, but a bit harder to sand.

When things warm up I'll spray it all with industrial primer filler as a base for the topcoat. Deck not glued on yet.

JB

Painted the acrylic undercoat filler on today, as the weather was good with not much wind, which is unusual for our winter (made spray while the sun shone 😀)
JB

Had a plan of how things were to progress, but ended up doing things differently. Made a bit much epoxy with filler powder up for the transom ply trim, so glued the deck on instead to save wasting too much epoxy. Needed all the clamps I had for the inner edge, -taped the outside.

Cut the transom trim (to be varnished) to about 1mm oversize, taped it in place and drilled a 3mm hole through the top corners and transom to locate the trim sheet for gluing. Clamped the hull nose down to a trolley, mixed some more epoxy and filler powder and applied it to both surfaces, then 'nailed' the sheet on with pointed 3mm dowels. Taped the edges and weighted it down. When set the edges will be sanded to the hull.

Painted the hull and cabin with acrylic white before doing these jobs, as we had a decent warm day for a change (being winter here) then sanded the cabin back again as it had some imperfections, carded on some thick primer filler, then sanded that back, and now should be smooth enough. I usually use US made aircraft dope to seal balsa, but the aircraft accessory shop (100%) hasn't had any for a long time.

I usually buy it in US quart cans,- excellent stuff for models. Hull will be wet and dry sanded again when the deck and transom are done.
Haven't fitted the shaft yet, as that can wait till the hull painting is finished.

JB

Varnished the front and rear cabin trims to be glued on after painting is complete, and spray rails fitted last night. Did a 100km return trip yesterday (80 mins) to buy more white acrylic which was on clearance. Paint was $27 for a 1L bulk can (plus $15 gas there and back) =$42, which a lot cheaper than buying 2.5 400ml spray cans at $32 each ($80) ! for the equivalent volume at the local branch 1km down the road. The things we do for models😐

Went for a wander while I was there to look at a new busway, cycleway, pedestrian bridge over the river, beside the 3rd road bridge (built 1959). It has displaced a small marina and haul-out ramp and removed about 10 houses during construction. Took about 3 years (including rearranging about 3km of the main road for a busway) and is the 5th bridge to be built here since 1865, with the 4th larger one about 800m upstream.

JB

Hull and cabin painting finished, despite sunny but cold damp weather (12 deg c), plus having to spray it outside not letting the lacquer gloss off. Required hours of wet and dry sanding and cutting to get the gloss back, - finishing with Brasso.. Had to re varnish the transom as well, due to the lacquer thinner fumes getting under the masking tape and attacking the varnish. Took a bit of sanding to remove 6 coats of varnish!. Paint not 100% as I would have liked finish wise, but you can't wait forever for a good day.

Gunwale rubbing strips are varnished and ready to glue on,- next will be the toe rails, then the basic hull should be finished ready for the deck jewelry. Cabin needs the windows fitting (tint film over .5 acetate sheet) and sanding to fit flush on the deck.(strapping sand paper to deck and lots of rubbing). Lots of other bits to make, (grab rails etc),- luckily I still have the jig I made for sanding the shapes in grab rails, as there are a few rails to go on.

Shaft and rudder will be fitted later, as they just get in the way at this stage, (everything is ready to fit). Cabin front and rear varnished trim pieces will be glued on later. Lots more to do.

JB

Gunwale rubbing strips have now been fitted and grab rails cut out. The grab rail cutouts were made using a jig made from aluminium angle. The cutout was done in the mill, and taken down to about 1mm to suit the 3mm square spruce. The material was beveled and marked out leaving 5mm between each 18mm long cutout, then clamped in the jig.

The rail cutouts were made using a sanding drum which was the same diam as the milled jig cutout ends, - and sanding them down from the back side to just touch the jig . This makes it very quick and easy to make the rails, with all the cutouts being identical. Any size jig can be made to suit the desired depth and length of the cutouts.

I've also cut the side windows from 1mm acetate sheet, applied a vehicle tint film and fitted them. In the process of cutting the front and back windows and varnishing the rails.

JB

More progress in the last few days, -grab rails varnished (leaving attaching till later as they are fragile) inner coamings almost finished, fitted a cabin seat with luxury upholstery 😎, all windows in, and a few mahogany trim pieces added.

I've noticed that many of these old style models have no doors on the cabins, (how does the skipper get in?) so I've added the illusion of a door on the stbd side, (if anyone's wondering, it's a sliding van type door😉) More 'bling' to go on and in yet

JB

Starting to add the 'fruit' now, with the anchor winch, spotlight, inner removable blanking plate, (cabin floor), bow and stern fairleads anchor guide, dash and support bush for the cable drive inner.

Anchor winch drum was made from a turned down large thumb tack. Fairleads and anchor guide were made in polyester resin, cast in moulds I had made previously, using a male hand made master to make an impression in modelling clay. Clay was baked till hard, impressions waxed and filled with resin, then popped out, filed and painted with chrome paint. Not perfect (depends how much you can be bothered filing with a needle file ) but cheap and can be mass produced. Still have a mould to make for some cleats.

Spotlight was made from 2 piece pop on furniture screw cover. One side drilled for a brass tube, clear LED (from stripped down xmas tree lights) inserted with neg lead soldered to the brass tube and the pos lead fed out the back. One hole will be drilled in the cabin for the tube and a small one for the pos lead, then a neg wire is soldered to the brass tube inside the cabin. The clear plastic washer which usually goes under a screw ( which the cover normally pops over,) is used as the lens. They light up quite nicely.

The internally stepped acetal bush was made for the cable drive to support the cable where it comes out of the brass tube.

The removable cabin floor/blanking plate covers the area where the ESC and RX will go,- also the motor, so they can't be seen. It's covered with black 3mm felt. There are 2 pivoting legs so it can be fitted through the deck and mount on the side blocks. They are folded back when removing or installing the floor, then turned out to sit on the blocks. I just used available scrap to stiffen the ply floor,- didn't need to be fancy as it can't be seen, and didn't want to cut good stock as balsa is really expensive here, (I still have boxes of ply and balsa scraps from all my past planes and boats, - you can always find bits to join if you are short) I think most of us are the same. Dowels are levers to move the arms, as they are under the floor and hard to grab hold of with sausage fingers.😀

Dash was made from thin Formica with printed gauges which can be backlit. Still have a wheel to make. More to add yet.

JB

Thought it was time for a few lights, so did the port and stbd nav lights, the cabin roof light and spotlight. Still have the stern, dash and maybe riding light to do. LEDs are stripped down Xmas tree lights as usual, and the voltage is controlled by a voltage regulator in the rear 'cabin'. I start off at min volts and slowly wind it up till they are looking bright enough (around 2.8v for these). Still testing but they look ok apart from needing blinkers on the side lights to make them suit the visibility rules😎

The mast is made from 3mm ply, with 1mm Mahogany veneer on each side. The base is drilled for 1mm brass wire and the cabin drilled to suit,. Not sure if I will glue it permanently or make it removable for transport, as they are usually the first thing to suffer from ramp rash. Waiting for the paint to dry on a radar which attaches to the mast.

Steering wheel and throttle quadrant done as well

Decals to make as also.

Lights are powered by a recycled 1s LiPo from a 2200mah 3s battery with a dud cell. Perfect for running LEDs through these small voltage regs.

JB

Started with printing some decals today but not happy with the stiletto decal. If you want colours to stand out better or need white, you have to use white decal paper. The problem with this is having to try and trim round the picture so you don't have any white showing.
I found a way round this by trying to match the background to the surface the decal's going on.

You can do this in paint, or in windows 11 in the photo editing section (remove/replace background) It's sometimes hard to match colours, even using custom colours, but there is another way I came up with, and that is to take a clear pic of the surface you want to match, then use that as a background and then add text or subject over that. This can work well on certain designs, as long as you are not too critical.

I managed to almost exactly match Chrysler Charger orange to that paint on one of my planes using that method. With the runabout decal. I managed to match the woodgrain on the decal to the boat. Using white decal paper is easy on white, and it stops the colours looking opaque. There are limitations with colours, but as printers can't print white yet, it can be a useful method.

Make the background large enough so it can be easily trimmed as close as possible to the subject, as this will make it less noticeable.

Another idea I came up with was how to save expensive decal paper. If you finalize your image, (center it if possible) then print it on plain paper (A4) to check the size, (adjust as necessary) then sellotape a piece of decal paper over that image, (make sure it covers the edges and is smoothed down flat, or it might catch in the printer) leaving about 4-5mm round the image so no sellotape overlaps it, (hold it up to the light to make sure), then place the paper in the printer tray so it comes out the same way as before on the same settings as before, and the printer should print pretty much exactly over the image. (rough example pic5)

Leave the image on the paper and leave the ink to dry (I put them in the oven at 50c till dry) then spray a few coats of clear over it (still taped to the paper), then let that dry (oven's good for this as well (as long as the boss is ok with it😉). When dry, trim the decal to suit and
apply. My reason for using this method to save decal paper is, if you use a whole sheet for a small decal, and spray the clear over the image, you can't print on any surrounding paper with spray on it.

Clear decal paper works best with dark on light (pic 4) as the other way round the decal can look opaque.

I have even managed to print on silk using the tape/overlay method. (pic 6)

JB

short video of the overlaid printing

Using the aforementioned method of using the actual background as the decal background, you can see the difference. I cropped the rear pillar pic and pasted it in 'paint', then did the same with the decal pic, sized it played with the colour a bit with Wind 11 photo ed to try and get the tone right, and overlaid that on the pillar pic using the transparent selection tool. Printed it as described previously, clear coated it when dry, trimmed it as close as possible and applied it.

The first effort was just trying to match colours with 'paint' which is usually not the best due to lack of options.

JB

Almost finished the lights now, having added a stern light and dash light. Also started on some bow rails and fitted the grab rails.

JB

More work done over the last few days,- Cable housing glued in and rudder fitted, water pump fitted, and yesterday my favourite bit of 'bling' the BT player with IR remote. This uses a cheap bluetooth player/board and 2 speakers. It can be used with a phone, watch or just the remote. I've added a small IR sensor on an extension lead from the board and installed it under the radar, making is more visible to the remote. The speakers are hotmelted to the top of some plastic honey jars, with cutouts for the sound, as an experiment to get more bass. Works quite well and increases the volume by 50%

I have a small multi function Ruizu BT player with FM radio, (about matchbox size) which can also be used through the board via BT, as a radio or music player (needs an aerial in the headphone socket for radio use). The board also has inputs for an external plug in player or pre recorded micro SD cards. A lot of fun playing with these gadgets, and very cheap and simple to set up. You can pre record sounds on an MSD card and play them via the remote, just by selecting a number, (ie comms sounds, sirens etc). Almost unlimited fun, and a hell of a lot cheaper than buying specialized units with one or two sounds.

This is the third model I've fitted one to now. Graham (93) has fitted a similar unit (with amp) to his rowboat, (with Bill and Ben) which works really well, and is audible from a reasonable distance on the pond.

Probably more shiny bits to come yet,- hopefully an engine sound unit as well with remote key fob start 🤓.

JB

Sound system is working better now with the addition of an amplifier board (from Ali Expr) Good part is that any sounds can be recorded and played using the IR remote, (as long as it's not too sunny) or sent to the boat via BT from a phone. Small sample vid of sound recording from the board and the small multi player BTing radio to the board. Can be left on board or used from the shore (only about 25ft range, so works best left in the boat)

I have added tinted hatches to the front and rear cabin tops Rear one can open and close but the front one is fixed, - only thought of a way of making them openable after gluing the front one 🤔 Rear one has a plastic (1mm PETG like the hatch) z shaped 'hinge' with a slot, which is held underneath the roof loosely forward with a screw, and a 2mm wide plastic strut at the rear with a z catch bent into it.

Started on a stern ladder tonight,- will have mahogany treads and a small platform.
Next- a dance floor 😂

JB

Got round to making the 'exhaust' and water systems yesterday. Fitted the air pump and plumbing for that and the water pump, and installed a pick-up behind the prop.. The Exhaust is the same type as smoke and water system myself and Graham 93 developed, and uses a large diameter tube with a smaller tube inside, and another small tube which enters the side of the large tube near the front. With the smoke system, the water runs through the center tube, and the air and smoke enter through the side tube, and mix near the outlet.

I won't be using the smoker side of it, just the air and water to simulate a water cooled exhaust (hopefully)- works on the bench so should be ok. I can easily add a smoker later if I change my mind. We came up with the idea to add an essential part to any inboard engined launch or runabout, as it's the thing most people leave out. Most boats have water outlets but no exhaust, so where does the exhaust go? (someone's going to say "but they're electric" ?🤔)

'Chromed' the front rails and ladder and added the mahogany treads as well last night. Drilled all the mounting holes for the rails and ladder, but haven't glued them in yet. Swim platform to make and a few other bits to add like switches for the pumps so they can be controlled by the TX, and it will almost be test tank time. Waiting for the weather to improve, but it's slowly warming up now.

JB

Almost there ! finished the swim platform on the transom and tested the water/air injected exhaust. I need to order a few finishing bits from CMB (cleats to go with the fairleads) which are too fiddly to resin cast like I did with the fairleads and bow anchor guide.

The video shows the air/water exhaust with and without air injection. The amount of splatter can be adjusted by moving the small plastic tube insert in the end of the exhaust pipe, in or out. The tube acts as a dam, letting the water completely fill the exhaust as a particular water pump speed (adjusted by a small voltage regulator under the pump tray). Air is also adjustable if necessary.

For a bit of fun and a bit more realism, I'm going to experiment with a proper wet exhaust design (ie 'waterlock muffler' ) which has chambers which fill with the expelled cooling water from the engine, along with the exhaust. The water is then pushed out in a spurt by the exhaust pressure,- more pronounced at idle. (pic of a vetus system). If I can get one working nicely, I'll fit it to the Stiletto.

Thinking of fitting an engine sound module as well, but the prices have increased a lot lately on Ali Expr

Should be filling the test tank shortly, as the weather is improving.

My son has moved back home for a while, so I have had to vacate my modelling room 😔🤔 BUT,- all is not lost ! I have managed to reconfigure my larger garden/storage shed as an emergency modelling area and added lights and radio.😊 Can even have TV if I add a splitter box to the LNB on the dish😀

JB

Finally got it's butt wet. Motor is too powerful (knew it would be but had to try as I only have 2 suitable motors with 5mm shafts to fit the cable collet) I have lots of outrunners but the shafts are on the wrong end and would require re working, (motors can be front or back mounted and to change them requires the shaft pressed out the other end). Motor was a 1400kv inrunner with an internal fan, for 4s LiPo, I've changed it to an 890kv on a 3s as the original was far to touchy.

Motor adjustments in the vid of the original motor are just using a few click of trim,- totally unmanageable in reality. Changed the ESC as well to see if that gets rid of some electrical noise, but the motor is solid mounted to the hull so makes a racket, ( not so bad with the top on)

I'd like to change it to brushed HV motor and ESC, so it can have reverse, but the collets to suit the smaller shafts on the brushless motors to go with the cable, aren't available, so may have to try bushing down the 5mm collet at some stage. One thing which is amusing is that the boat sits with the chines 1/2" above the water, due to the light balsa /glass construction (originals in ply) with the deep V. Had an idea that might happen (probably needed to scale up the weight as well). When going from 26" to 1m and re designing the whole boat from a blown up plan, - everything changes.

The water and air pumps (previously described) are switched by 2 servo operated micro switches (seen in my usual spaghetti) and can be individually operated ( can be seen in the tank video) for cooling (if needed) and exhaust effect (and just for fun😊)

If things check out reliably, a pond test might be the next effort.

This boat's a bit of a tribute to Peter Gargan (Red PMG) in SA who kindly sent me a copy the original plan he had reworked for laser cutting. Sadly he passed away in 2022 so didn't get to see it done.

JB

Testing the 890kv motor,- runs well albeit a bit noisy at a transition frequency (motor hard mounted) Moved the stereo setup (BT board with amp) to under the cabin roof with the speakers under the hatches which works much better. Still have some wiring to tidy for it.

Motor is very economical and ran for 30 mins continuous at cruising speed, but still had 15 mins left at least. Much softer starting than the bigger inrunner. The 4000mah 3s LiPo was only down to 3.9v/cell after 30 mins continuous, (got tired of waiting so stopped at that.) Should have around a 3km endurance as battery was only at 90% at the start.

JB

Adding a few internal bits while waiting for a decent day for a sea trial. Stereo is working well and spaghetti tied down,- runs off 2 separate 1s 3000mah LiPo cells (good cells recycled from old batteries) Also added a thermostatic fan control for the ESC in case it gets hot. A 30 deg C thermo switch has been screwed to the heat sink on the ESC along with a 6v fan with a voltage regulator (uses a 2s LiPo for a supply). If the ESC gets above 30C the fan will come on, then switch off at around 25C. All self contained and automatic.

A buzzer can be connected as well for an audible warning. Cheap insurance, as these switches can be strapped to motors, batteries or whatever. Different temperature switches are available from Ali Expr very cheaply. They are rated 220V AC 1A (work on DC -plenty for small fans or buzzers) or can be used to switch relays for higher power requirements.

Makes an interesting feature if the fan comes on while you are running the boat, you come in, turn the RC off, then a few mins later the fan switches off by itself.

Still some small fittings to put on, but 98% done now. Will probably think of something else to add later. Have also ordered a GT Power sound module for more noise, which should arrive in a few weeks.

JB

Have just received the new 45A Surpass ESC and GT Power engine sound system, and have them installed. I had a 6ch RX coming to solve an interference problem between the sound unit and the motor. The sound unit uses a siamesed lead for the ESC and the unit to plug into the RX throttle, but the sound system would go berserk when I turned the water pump on using the previous set-up.

I had the same problem with the Russian work boat, and solved it by using another smaller 3ch RX and plugging the sound unit into the throttle on that. Found with this ESC I don't have that problem, so won't need the other RX. I fitted 3 capacitors to the pump motor, plus a ferrite clip on sleeve to its' power lead, but not sure if it was that or the different ESC which did the trick, but the capacitors had to be a good thing anyhow.

Motor is not as smooth with this ESC, especially at low throttle, - sounds like the timing needs changing so will need the programming card to see if it can be done, (doesn't appear to have the normal manual setting mode,- no instructions for that anyhow.) Most ESCs have the same method of entering the menu, but doesn't seem to work on this one.

I have another few motors I can try which might be smoother if this one gives problems,- 2 nice smooth 1500 kv heli motors with built in fans,- but they might be too fast.

Re the cooling fan which comes fitted under a cover on the new ESC,- this runs constantly with the power on, so I have interrupted the fan power neg lead from the micro JST plug on the ESC, and screwed a 30C thermo switch to the side of the heat sink, so it will now be automatic on-off, and won't waste battery power when sitting still. I don't anticipate things getting too hot with the motor I'm using, so it should do the job.

Still a bit noisy and coggy, but it's not possible to easily rubber mount a motor and keep it lined up. Now need a nice calm day for the test run, (airboat rescue boat will be on standby😉)

JB

Finally! a decent enough day for a first sea trial. Runs perfectly but the ESC Motor combo has a nasty frequency noise just where you don't want it at slow speed. Wasn't so bad with the 'red brick' one way aircraft ESC, but needed reverse. This Surpass ESC isn't smooth at all at low speeds,- even tried other motors but all similar.

May go to a HV brushed motor and ESC to see if that fixes the problem (hate noise) . I have 2 of those motors in my vintage runabout, and they make far less noise than this lot. Thought the boat sat too high in the water (due to balsa / glass construction rather than lots of ply) which might have been a problem, (torque roll) but with the cable drives' low angle it runs and turns pretty well, (could do with the rudder size increasing for reverse).

Fairly happy with it except for the noise. A bit breezy on the lake to take decent pics, kept sailing down wind sideways at 1kph and wouldn't stay put. Total run distance on the tests was .777km, top speed 11kph, (Sky RC GPS) and 3s 3000mah battery still at 9.8v/cell, motor cool.😀

JB

Changed to a 37/56 1600kv heli motor, which has an internal fan built into the back end of the can (pic 2). I bought 2 from HK years ago and never used them,- finally found a use for one. Seems to be a bit quieter that the other 3, but you can still hear it cogging/snapping up to half throttle. I think the problem is with the ESC as none of the 4 motors tried will run smoothly, (might be a dud). Might have to try another ESC, as none of these motors had a problem before.

This motor is the best of the 4, so will give it a go on the pond. It can take up to 4s, but I'll try it on 2s or 3s. Only pulls around 6A at max so not too bad,- cruise at around 2.5A, so should get a decent run from 3s 3000mAh LiPo. Sounds a bit loud in the vid with the cabin off, but the camera mic is very sensitive, so not as bad as it sounds,(a bit like a 550 brushed motor) We shall see.

Hoping to do an endurance run up our beach which is 3km long if we ever get a flat calm sunny day, and follow it in my 12ft dinghy. Not many days like that in recent years, plus the tide has to be right to get the dinghy out of the river. A lot of coinciding needs to happen.
If you listen till the end of the vid, you will hear the auto fan turn off when the ESC is 28C.

JB

Sounding more acceptable with the cabin on

JB

Did a bit of tidying of the wiring, removing bits etc (not that you'd notice) added a thermostatically controlled turbo fan at the front of the motor, - run from a UBEC off the main battery, repositioned the sound module, repositioned and raised the cabin 'floor' and added magnets. I've also made a cut-out in it for the sound unit.

Added a couple of small guides on the inner comings at the stern as well, to make fitting the cabin easier. Cabin only fits in one place exactly, and was a bit tricky to get on. Just used small blocks with tabs of acetate sheet plastic, bent inwards. 4 magnets hold the cabin down. Just making a few small refinements while waiting for some decent weather.

JB

Running well now with the new heli motor. Small temporary prop (35 diam) on the 1500kv motor lets it go slow enough, but also has good speed (24kph/13knots on the GPS) Throttle end point is only at about 75% so plenty of room for 'ridiculous mode' - also can go with a bigger prop and bigger battery (motor is for 3-6S LiPo and 55 A max) - no real need though as it's more than fast enough like it is.

The new ESC (45A) overheated at one point, at only around 8A! and turned itself off for about 30 secs till it cooled down, then came back 'on line' and was away again. The output from the ESC is erratic as you can hear, so have ordered another 60A ESC to see if that will be better. Noise is actually not any worse than my vintage runabout, with 2 high voltage 550 brushed motors at a similar speed. The cables are in a plastic tube inside a brass outer, and are greased, but can flex slightly and make a bit of noise (unlike a solid shaft) so could be where a bit of the sound is coming from,- plus the motor being solid mounted, -but a 90% improvement over the first motor. Anything going fast will make some noise anyhow.

Still a bit coggy at low revs , but good enough for now, (might improve with a different ESC) Still may need a bit of tweaking here and there, but nothing major. Hull runs perfectly with the shallow angled cable drive and corners well. Still 3.8v/cell in the 3s 4000mah LiPo after a number of fast runs and cruising around for about 20 mins. If I went to 4s, I could dial the throttle back quite a way and still get the same speed with less voltage loss. Plenty of options with electrics.

JB

one of todays runs.

Thought I'd have a go at converting a brushless aircraft ESC to having forward and reverse. I've found that the aircraft ESCs perform better than the car ones, and usually have more tuning options, including timing and PWM changes. managed to get a set-up working, using a double gang on-on switch and a Red Brick 50A ESC (also with an RCS 30A).

The switch is cross wired (X) between opposite terminals and fed to the center terminals from the ESC output. Only 2 motor wires go in and come off the switch, with a bypass wire for the 3rd motor wire from the ESC. This wire is the same length as the combined cross wires and output wires to keep all the wires the same length. I've used a servo to switch the direction, and everything now works from stick to the bottom for 0. Throttle is from the bottom forward as with a plane, then back to the bottom, switch over to reverse and forward again for reverse.

Switch is a 240V 20A which is plenty for this setup with moderate speeds. The 30A ESC got a bit warm, (with no cooling) but the sun was blazing and the temperature of most things inside the boat was 32C + for a start. Changed to the 50A ESC and it stayed cool enough without a fan also. Both the plane ESCs ran the 37diam heli motor smoothly and ran very slowly with almost no cogging (noise is just the bearings in the motor amplified by the hull and very sensitive mic on the camera) actually sounds like a brushed 550 motor,- very quiet, You can see the difference with the 45A Surpass car ESC in the 3rd part of the in boat vid (ignore the sound unit, should have unplugged it) which has horrible cogging/snapping at low revs,

Built the complete unit after the boat test and tried that out, and it all runs perfectly. Looks a bit agricultural but thought I'd give it a go as I've never seen it done before. The aircraft ESCs are generally a lot cheaper than the car/boat ESCs, and are easy to add a fan to if necessary.
Could be made more compact, but this is just a prototype, -keeps the braincells moving😀🤓
JB

More changes than a womans' mind, 😀 Now have the Hobbywing 60A brushless ESC installed and tuned in. Works very well, - much better than the previous 45A Surpass rubbish, -should be at twice the price (but only 3/4 the size). Runs smoothly and quietly with virtually no cogging at low revs. I need to find a way to give it a wider center dead spot, (mainly to sync the sound unit start to the throttle start), as the largest one in the settings is not very wide (almost non existant) Probably could get round it by using the 'double tap' setting for reverse, but that's always a pain and a bit hit and miss, (don't want to be flying at the jetty and miss reverse☹️)

This ESC has timing settings if you need them (can give more torque and revs if needed) but better left on the std setting (0 deg) initially. Turned the throttle end point back to 50% on the TX for economy, but will make final settings for a sensible speed on the water.

Recorded some air horns with my video camera, converted the vid to MP3 and added it to the sound card in the on board stereo. Works quite well, (now need to make some trumpets for the mast) Pretty much finished now apart from a few detailing items (anchor etc). Now waiting for a flat calm, sunny day, with the right tide for launching my dinghy, and the outboard running well (not too much to ask?) and I might try a sea endurance run.

JB

Finally had a decent day to test the new Hobbywing 60A ESC on the pond. A big difference between this and the 45A Surpass ESC as there is no cogging and it runs smoothly through the throttle range without missing a beat as it did in the tank. Seems like an excellent ESC. Throttle is limited to about 70% but might cut it back some more, as it is unnecessarily fast.

Managed about 25 mins of running fast and cruising on a 40000mah 3s Lipo, so not too bad. Maybe up to an hour if I just pottered around. I also replaced the infra red pickup extension under the radar (for the stereo remote) as the previous one had died, so that's back to working.

JB