TFL Patron Saint "Outerlimits" "Lucky Oct" 1330mm brushless buid

[Old School]

I have commenced the build on this boat. Started with a new bare hull. First task was to blank off all the holes in the hatch originally intended for the gasser model. Next task was to fit a 30 cm long carbon fibre plate longitudinal bulkhead under the foredeck. Initially I intended to bond a lateral bulkhead under the forward edge of the hatch cutout after I had fitted pool noodles under the foredeck. My thoughts now are to screw the lateral bulkhead to the aft edge of the longitudinal bulkhead and then using a sealant bond the lateral bulkhead lower edge to the hull inner vee. This should minimise any fretting that may occur between the CF plate bulkhead and the hull fibreglass inner surface. The bulkhead should then be able to be removed should the forward part of the hull suffer any damage.

The basic hull is very nose heavy so I am wary of too much weight up forward, so considering the thickness of the hull, I will be doing a single layer CF cloth outboard of the rails up to the hatch opening forward edge and then a double layer for 0.5 metres forward from the transom in the centre section of the hull. The transom inner face will then receive two layers of CF cloth and then a final layer of 1.5 mm CF plate. After the cutouts have been made to accommodate the Arneson drive I will then insert two dual cooling water inlet plates each side of the vee as close to the transom as possible. By having a total of four inlets I intend having independent pickups each side for each of the motor and ESC.

The intended drive is a T20 Turnigy motor running 730kv on either 8s or 10s. 10s is the maximum voltage for the motor. The T20 is an interim motor for testing/installation purposes as a more powerful TP Motor is a possibility as I have doubts as to the overall performance of the Turnigy motor. I have sourced a 5 inch rail mount for the motor and have test fitted this to the hull. The original cutouts in the stock fibreglass rails matched the motor mount perfectly, just requiring a quick wipe with a rat tail round file to allow the 5 mm mount bolts to fit through the rails. The ESC most likely will be a waterproof Hifei 300 amp model. A 2200 mah LiFe battery will supply the receiver as there will be two interconnected servos to operate the cable steering TFL Arneson drive unit. Most likely a 60 mm 3-bladed prop will be used for initial testing. I intend four batteries (two each side of the motor) with a bias towards the rear of the hull due the stock nose heavy hull. Hopefully, CoG will be able to be reached in the 26 - 28% range.

The build will take sometime as it seems that every little bonding task takes hours for the epoxy resin to cure before the next step can occur. The stock hatch will be reinforced with several layers of CF cloth and retained to the hull with six mount bolts fitted to underdeck 4 mm nut plates bonded to the underside of the lip on the hull. The two centre nut plate mounts will require an extension to be bonded to the underside of the lip as the stock lip is not wide enough in the mid location. Images will be provided as the build continues.

[Old School]

Some progress to date. First image shows the two lateral bulkheads (not yet installed). The forward bulkhead is to support the forward deck in a capsize and retain the pool noodles. Due the length of the opening in the deck I have decided to fit a mid bulkhead to retain rigidity in the hull sides. This will be located forward of the location of the motor and ESC and firmly bonded to the underside of the deck and to the hull inner surface. Second and third images show the numerous holes that need to be blanked off when the hatch is converted to brushless power (seven cutouts in total). Last image is a work in motion depicting how I hope to power the steering on the Arenson drive. The servos will be inset in a removable CF plate located just aft of the motor location. The reason for a removable plate is so that if the twin servo operation does not work then I can cut out another plate to mount a quarter scale servo with a single operating arm.

[Old School]

This afternoon I carried out the messy bit, an inlay on the last 2/3 of the hull. If considered necessary I will extend the inlay on the centre section between the rail up to the forward edge of the hatch cutout. Before commencing the hull was cocooned in multiple layers of cling wrap film as it seems no matter how careful one is there always seems to be messy fingerprints of resin left over on the surface. For this inlay I followed my son's advice and used many, many pairs of disposable plastic gloves. While the iron was hot I bonded in two battery trays either side outboard of the rails. With the hatch I bonded two strips about 2.5 inches wide down the underside of the lip on each side and clamped the hatch down to a solid board. Hopefully the slight bow in the hatch will be gone after the inlay has cured. When further CF cloth arrives from China I will complete the inlay on the hatch underside. I want to be able to bolt down the hatch to the hull when I apply the remainder of the CF cloth so the hatch will contour to the deck lip as the cloth cures. I am very relieved that this part of the build is behind me.

[Old School]

I have a feeling that CoG may be an issue. I am hoping to achieve between 26 - 28%. The forward mount of the motor is at the 28% mark, with the motor location dictated by the stock location cutouts in the rails. I had hoped to fit the ESC (weight approximately 450 gm) just forward of the motor to limit the length of the wiring. Placing the ESC there will require a lot of additional weight aft. Still to be fitted are the Arenson drive, steering servos and batteries. I intend running four packs plus the LiFe receiver battery. I have a feeling that the batteries will need to be at least 750 - 800 gm each if I am to achieve just the 28% mark. Battery physical size and location (how far aft they may be placed) will be conditional on how far the steering cables intrude.

Edit: further "experimentation" using tins from the pantry show that with the ESC located forward of the motor then 30% CoG should be achievable. It will all be down to final weight and location of the four batteries to get the CoG further aft.

[Old School]

I have almost reached the point of installing the Arenson drive. A close look at the unit shows it to not be very user friendly as regards regular servicing. Unlike a regular flexshaft arrangement which simply requires releasing the motor collett and removing the shaft for cleaning/greasing, the Arenson requires a bit of disassembly to grease the shaft within the drive tube, plus accessing the articulation section under the rubber bellows. To further complicate matters, removing the flexshaft requires the removal of the motor. And further complication, if the teflon liner is to be removed then the stuffing tube itself needs to be removable. I intend using the shaft bearing with integral oil supply to the flexshaft as used on many gasser boats, so the teflon liner will be inside the end of the stuffing tube and not able to be withdrawn without removing the stuffing tube. I will also be using the 5" rail "T" bar to clamp the stuffing tube at the forward end. The aft end of the stuffing tube fits inside the forward end of the Arenson drive unit so is supported at the aft end, plus there will also be a small triangular tube support bracket to position the aft end of the stuffing tube should the complete Arenson drive be removed. Thus a fair amount of disassembly is needed each time the unit is serviced. Given that there seems no information on the drive from the factory nor any experience reported of anyone using the drive, I am in unexplored territory. All the factory provides is a printed sheet showing the components. What would be preferred is a breakdown of servicing intervals. A plus is that the flexshaft is basically sealed off from the water so hopefully flexshaft servicing is not a daily chore, unless the rubber bellows splits allowing water to seep past the ball bearings inside the stuffing tube.

Another consideration is whether the drive unit is capable of reliably turning gasser size props or whether the drive is basically a "scale" unit. Personally, the drive pins in the articulating unit do not impress me as I see those as the weakest link, apart from the other flaw in the design, the rubber bellows that seals not just the articulation unit but also the ball bearings. A simple fatigue crack in the bellows will lead to destruction of the drive. The lack of technical and support information from TFL does concern me. This is not an inexpensive unit and as such should be supported by the manufacturer in a more consumer friendly manner. I am understanding now why there seems little consumer feedback information on the TFL drive unit as it really is not very user friendly. If one goes to the Arrow Shark Marine website there is a lot of information available on their drive, however, with TFL all you get is a list of components diagram and nothing else. TFL assumes that whom ever purchases the unit has the knowledge and expertise to install and maintain the unit. Assuming a steady supply of replacement parts then I possess the means to install and maintain the unit, however, simple basic information on the unit would indeed be of assistance. Would I recommend the drive for others, an emphatic NO!!!!!!!

Edit: Further to above, given that the aft end of the fixed driveshaft is supported in some form of copper coloured bushing I may look to installing a Speedmaster style rotating bushing as I can see the stock bushing wearing out in no time with turning a prop around 65mm diameter.

Edit #2: Further looking at what is required to install the drive there is simply no information on setting up how far apart the steering "actuator" mounts need to be fitted. I am assuming that the mount brackets should be installed with the rams approximately mid-travel. I calculate that the inner edges of the mount brackets would then be mounted 35 mm each side of the transom vertical centreline with the "actuator "rams" horizontal. A rotation check shows that any deflection beyond about 15 degrees from neutral causes the articulated "universal joint" to lock up. I will need to see how servo travel can be limited to prevent the drive going beyond around 15 degrees deflection. This may require me to redesign my previous dual servo set up. Also, because the steering cables enter the transom basically below the waterline at rest, then I need to make sure the cables exit well above the waterline inside the hull. It will be a challenge to get the drive operating reliably as I am thinking the drive is more a novelty "scale" item rather than a truly functional drive.

[Old School]

Some progress. Six captive nuts fitted to the deck lip to retain the hatch. A neoprene seal will be fitted around the lip on the deck. My K&S brass tubing arrived from the OSE store this afternoon so I decided to see how I will be able to route the steering cables on the Arenson drive. The drive is supplied with a spring wire guide tube with plastic coating which is intended to route the cables through the mount bracket and then to the servo arm. As can be seen in the upper part of the image the guide tube is more rigid than flexible so I decided to bend some 7/32" brass tubing to give support to the flex tube and provide a better translation for the cable through the mount bracket. To retain the 7/32" brass tube inside the mount bracket required three additional telescoping brass tubes (approximately 22 mm each) ranging from 7/32" up to 5/16". This gives a firm hold in the bracket. These telescoping tubes may need to be bonded inside the bracket to secure them.

Hopefully, with spacing the steering mount brackets 70 mm apart on the transom, the tubing will enter the hull still within the rails. This is important as I do not want the cables outboard of the rails as I need to position the batteries fully aft to maintain a reasonable CoG and thus the cables would intrude into this area moving the battery location forward. The 7/32" brass tubing will then be bent through an "S" shape to bring it up to align with the servo arms and be above the waterline. I have purchased some rubber bellow seals as used on the pushrod on transom mounted rudders, so possibly these may be fitted to the cables to seal off any water ingress along the cables. As stated in my previous posting the steering cables will be below the waterline at the transom with the boat at rest.

Edit: a quick mockup shows that barring a tighter curve as the cable exits the steering mount bracket on the inside of the hull (I am reluctant to do this), the brass tubing will be positioned just outboard of the rails. I had previously removed about 3 cm from the aft edge of each rail to accommodate the cables coming through the transom inner face. This may need to be revisited.

[Old School]

Just a cosmetic update. The hatch had two cutouts at the aft end which on a gasser boat would have been stainless steel air exhaust grilles. On my hatch I bonded CF plate on the underside and then decided that a little cosmetic treatment was needed. Two air intakes were acquired from "LittoHot" (from memory formerly known as "rcbuild") that matched the footprint of the cutout section on the hatch. My intention is to disguise the large exhaust manifold cowling on the hatch moulding. The air intakes will be most likely painted a silver or stainless steel colour to match the silver in the hull stripes. I doubt it would be possible to exactly match the red/orange body colour.

The intakes are well made. The fibreglass has a white gelcoat finish. They are supplied hollow. I attached a 1.5mm CF plate piece to the underside of the intake, then sealed it off and filled the inside with around 6 - 8mm of filled resin (I added Aerosil powder to the 5:1 resin mix). This will provide some additional rigidity to the intake. I am thinking that the intakes will be secured with a thin sealant to the hatch so that if the inevitable occurs and the boat capsizes at speed then the intakes will just shear off leaving no damage hopefully to the boat itself. The site has a large variety of intakes available and the service was five star quality.

[Old School]

Unbelievable, the curse of the TFL Arenson drive unit. This is one step forward, two steps back. Of the nearly twenty or so mount screws that are supplied by the factory not one is able to be used. The mount screws are too short even for a factory stock hull. I need to see if I can find screws long enough. I was able to use but one screw only and that is the horizontal lock screw that mounts the yoke on top of the drive housing. The unit is expensive enough without having to source all the mounting hardware as well. The image shows the drive located but nothing is able to be secured, nor can I progress the installation any further until I source the longer screws. Even if I place an order today it will be the end of the month from the U.S. or possibly the end of next month if I have to source the mounting screws from China.

Hopefully, in the interim I will be able to work on the internals such as stuffing tube fabrication and motor and ESC mounting. I would though have liked the Arenson drive to be firmly mounted to the transom before progressing further. No wonder I cannot find any installation information on the web as this unit is a disaster. For very little additional cost one is able to buy the Arrow Shark Marine Arenson drive unit which seems a far more robust unit plus there are full installation and assembly details on their website.

Edit: fortunately, I was able to source the screws required from interstate, so hopefully, I will only be delayed a week or so.

[Old School]

The Hifei 300 amp ESC and 5 inch "T" bar rail mount arrived this afternoon, so to "console" myself, I looked at how I will be able to arrange things. If I go with as shown then the ESC motor wires will mount directly to the motor. The disadvantage is 0.5 kg of moment weight forward of the CoG. It is a convenient location so might be the preferred choice. I feel the ESC will need to be mounted upside down for access to the motor and battery wires.

[Old School]

Further progress. The stuffing tube is mocked up. I am still awaiting some 10mm brass tube as a sleeve over the stuffing tube where it enters the Areneson drive unit. When the Areneson unit is bolted in and the sleeve fitted then I can bond in the carbon fibre tube support towards the aft end of the tube. This will allow the Arenson unit to be removed and the final shaping and setting up of the stuffing tube, allowing the alignment of the flexshaft and motor collett to be confirmed. The tube still needs to be positioned about 3mm further aft and then adjusted for length where it exits the 5 inch rail T-bar. The stuffing tube by necessity will need to be removable in service for maintenance. The pinch clamp on the T-bar should be enough to counter any tendency for the stuffing tube to rotate.

Edit: I carried out a test of the drive. The flexshaft was lubricated and connected to a cordless drill. As stated in an earlier post the angle of operation of the drive is a maximum of around 15 - 20 degree deflection each side.

[Old School]

The acquisition of four Nano-Tech 5100mah 75C 4S batteries has shown that with the battery trays installed as shown, the CoG may be altered from 27 - 32% approximately. I think that this range should be adequate for most conditions. My longer screws have arrived and this will allow me to progress the Arenson drive installation plus mount the motor and stuffing tube. Then progress the steering cables and fitting of the servos. I have been fabricating a mount for the ESC and am awaiting the arrival of some G10 fibreglass plate to complete a mounting for the battery terminal connections at the ESC interface.

Edit: I had hoped to fit a rotating bush to the Arenson drive and had purchased two sets of a three piece 1/4" drive brass bushing set, but alas, I had not noticed that the shaft diameter inside the Arenson drive casing is actually around 8mm diameter and it is only the exposed portion of the shaft that is reduced to 1/4". More parts for the parts bin for another build maybe.

[Old School]

Finally some progress. The water pickups are now fitted and the Arenson drive temporarily bolted up to enable the stuffing tube alignment to be carried out. I found that I had to raise the mounting points on the T-bar by approximately 0.250" to allow a better alignment to the motor collett after physically bolting in the Arenson drive. Previously, I had relied on friction holding the drive in place on the transom when I initially was setting up the T-bar and stuffing tube.

A point that surprised me was how thin the hull was when I cut out the area needed to be removed for the water pickups. The seller had praised the hull in his blurb stating there were four layers of fibreglass laid up. The removed section showed the gelcoat to be thicker than the actual layers of glass cloth. Fortunately, I had decided to lay up two coats of CF cloth initially or else the hull would have been quite thin in the area of the ride pads.

Also shown but not fitted are the midship bulkhead and the ESC mount plate. The build is taking quite some time as every step requiring resin bonding takes literally a day before further building is able to take place. I prefer slow cure resins as they generally result in a stronger more stress tolerant join.

[Old School]

A little more progress. The Arenson drive is physically installed for bench testing. Final installation will see the transom mount brackets sealed with a thin sealant, particularly as when the boat is at rest the drive and steering brackets are beneath the waterline. The interior image shows the steering cables exiting the transom inner face. I need to decide how the cables will be directed upwards and attach to the servos which will be mounted to a CF plate traversing the width of the rails and just aft of the T-bar. The final shape of the 7/32" brass tubing will be by trial and error as I want to avoid placing too much friction in the cables. Hopefully where the steering cables exit the forward end of the brass tubing I will be able to fit a rubber bellows to seal off the cables from water ingress.

If anyone is foolhardy enough to install one of these Arenson drives then sleep on it and await your decision the next day. These are a right pain to install and given that there is apparently no information available, the install is by common sense and guess work. I mounted the inboard faces of the steering mounting brackets 80 mm apart (40 mm either side of the centreline) and the "hydraulic rams" level with the saddle bracket that mounts them to the drive tube. Set up like this a static test shows the drive is able to freely swing either side of centre. The 80 mm distance also nicely exits the cables just outboard of the longitudinal rails as seen in the image. This will slightly impact on battery location but everything about this drive install seems a compromise. Still to fit on the transom are the trim tabs.

Edit: it seems absurd given the size of the hull but it seems the only logical position for the two steering servos is just inboard of the rails and between the T-bar and the aft motor mount. There is still adequate room to work on the motor collett. I am limited mainly by eliminating tight radius bends in the brass support tubing, the length of the steering cables and the battery location. I also need to ensure that the cables exit the support tubing above the waterline. To mount the servos aft of the T-bar (preferred location) would require very tight bends and increased friction.

[fweasel]

Coming along nicely.

[Old School]

Many thanks. It does seem to be taking forever though. I was limiting workhours to when my partner was at work but now the "cat is out of the bag" I will carry out work even if she is at home.