Model Boat Mayhem
Mess Deck: General Section => Beginners start here...! => Topic started by: Phantom_Maloo on September 03, 2013, 04:05:45 am
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G'day Guys,
First boat build has begun went with the Aeronaut Ramborator Springer Tug kit. I know there are free plans out there but i liked the fact that it was all in the box for me to pop out and glue together. I'm using some Great planes Aliphatic resin glue I've had since i was about 16 don't know if this stuff goes bad but it seems to be holding so far. Kit was sourced from Cornwall model boats along with a graupner Eco 600 size motor a 35mm prop and a coupler and motor mount although as it turns out i didn't need the last two items as the kit comes with a motor mount and a coupler incl. So into the spares box with those parts for a later project. Very happy with the service from Cornwall took just over a week for it all to arrive via UPS. Attached is a few pics of the box and first construction steps underway.
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second pic
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First step glue drying :-))
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Second step glue the hull sides to the front piece making sure it's at 90degrees there are no plans to pin the parts onto make sure it's all square so i've taped the rear stringer to my bench and placed the hull sides on it so it's not too far out of whack the third step is putting all the bottom stringers in so thats where I'll ensure everything is square.
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another shot of step 2
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Step three bottom stringers glued in everything checked for being 90deg being left to dry overnight
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Build is progressing well I've got the hull bottom skinned now will post up some pics tomorrow. However I've run into my first problem. The next step after skinning the hull is to mount the motor onto the wooden mount bracket so you can line up and glue the prop tube in however the kit doesn't come with screws for this and neither did the motor packet or motor mount i purchased at the same time. Does anyone know what size screws the Graupner motors use?
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motor screw size should be 2.3mm dia
Jim
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Thanks Jim I'll see if i can find some at the local hardware or hobby store :-))
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Couple of pics of the hull skin going on. I glued the front end first and allowed it to dry for about an hour then glued the remainder fit was really good only had one or two small gaps at the bottom of the curve but i've run a bead of gap filling CA around the whole interior of the join so this shouldn't be a problem.
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Got some M3 bolts from the local hobby shop motor is now attached to the mount plate, prop tube and coupler fitted now ready for test fitting into the hull.
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Phant..don't forget your ventilation holes in the motor to wood! You probs haven't though,just a reminder...good thread.Bob.
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One of our club members Chairman in fact has built one
The rigid coupling and the ply mount caused massive
vibration.
A flexible coupling solved the problem.
Ned
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Hey guys,
Thanks for the comments I've been testing fitting the mount and prop shaft support parts they all seem to line up pretty well the instructions don't mention glueing the outer shaft to the support parts although i assume this is what you have to do using two part epoxy? I did order a multicoupler when i got the kit but looking at this i think this will be too long I'd have to get a shorter coupler also i didn't order the M4 attachment part for the other end. I was going to use two part epoxy and some square or triangular stock along the base of the mount to give it some strength. I haven't thought about cooling holes in the mount I thought that the cooling vents at the rear of the motor would have been adequate i don't know if i'd have enough room to cut holes in the mount without weakening it what about putting washers on the motor side of the mount to push it away from the mount? Please note the parts in the below pics aren't glued in
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I've been thinking about how to aleviate the reported vibration issue using the stock rigid coupler. My basic idea is to run a square stringer from the side of the hull glued along the top of the mount to other hull side then have two square pieces glued on the vertical sides and finally a strip of either square or triangular stock running along the bottom of the mount glued to the hull sheet and along the front of the mount glued on the existing hull stringer. Comments more then welcome {:-{ . Also in regards to the final install of the prop shaft the instructions don't clearly spell out that you need to glue the prop shaft to the hull i'm assuming that you are supposed to do this using something like two part epoxy which will also seal any gaps, is the case?
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outside of the hull glue areas?
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yes 2 part epoxy where you indicated.....As for the vibration issuses wouldnt it be better to glue some gussetts from the motor mount to the hull this would stiffen up the mount as well
Dave
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Flat 1/2" wide ply along top of cross-member T style, then two triangles vertical alongside the motor would be a better solution. Use a silicon tube on the splines of the U/J, ie no square middle part, that is the noisy bit. Beat me to it Stav. Pictures might help. They are of a metal mount but show the cut outs for cooling air to pass through.
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:-)) Thanks for the comments guys very helpful i didn't even think about triangles alot simpler i've got some ply lying around so i'll use some of that if i can't get enough from the left over parts from the kit. In regards to the silicon tube is that just the same stuff you use for nitro engine fuel lines? I've got plenty of that lying around not sure if it will be the correct inner diameter although it can stretch a fair bit i suppose. i made a template of the front of the motor by taping tracing paper to the front and marking the mount holes and cooling vents so i can lay it over the mount and mark and drill the cooling holes out. I ordered a mtroniks plug'n'play esc 15amp last night so when that arrives i can start wiring it all up. Using a 7.2V Nimh 4200mah 6 cell pack, Spektrum Mr200 rx and dx2 tx
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Use the silicon tube that is for joining exhaust pipes on a glo/nitro i/c engines. It should be a tight push-fit over the splines, fuel lines are too small. Triangles plus a square strip of hardwood along bottom of engine mount (see sketch) and a cap-strip along top, epoxy and the odd panel pin might help as there will still be vibration, not massive but in the "hum" region. Keep posting your build, looking good.
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I built one (my first model boat) this year and was advised not to use the wooden motor mount as this restricts where and what batteries you can use, I also used the deck as a jig when building the hull.
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Good point, if using heavy batteries, 6v 4.5Ah gell cells for example, it would be useful to have some fore and aft space for trimming. I run my Springers slightly stern heavy to counter the diving tendency when under full power. They do need the extra weight to have a correct sit in the water. If I was doing a Ramborator I`d put the bulwarks from around the stern on the bow instead for the same reason, or even all the way round the deck from some spare ply. Looking at some pictures of the kit , I see that the motor mount piece doesn't even go to the hull sides, poor design, if you cut it at the holes and use the off-cuts at 90* that will give space for sealed gell batteries one each side and stiffen the mount (like the triangle/gusset idea ). Be sure to coat the inside of the hull with paint or resin before closing up areas that will be inaccessible later. Put as much buoyancy foam as you can in these areas too, better safe than...etc. They sink like a stone...this I know :embarrassed: O0 :embarrassed: :((
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I can't seem to find my calipers but using a steel ruler the coupler insert seems to be about 8mm diameter including the splines, a mate of mine is a mechanic and he said he can get me some 7mm internal dia Silicon Vacuum tube. Price is right :-))
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Price will be a couple of tinnies :} . Copy the rear bulwarks and put them on the front. You could buy or make a metal motor mount, about 5£ on ebay or mate with mechanics skills and a bit of ally angle. Three tinnies. {-)
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Before the deck is fixed I would give it a good long run in a test tank/bath at the highest throttle setting you can.
Check the motor for heat and if needed it will still be easy to fit watercooling.
A length of auto brake pipe will do the job. (More tinnies to your mate O0 O0 )
Most of the homebuilt springers with 600 size motors seem to need a bit of help with the cooling.
Ned
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I'm going to coat the inside of the hull with Z-poxy finishing resin i've used this stuff before on model aircraft so i'm familiar with it. My local hobby store had some deluxe materials "eze cote" which seems to be the same thing but easier to apply but i think i'll stick with what i know and use the z-poxy. How much ballast weight do one of these models need? i'm going to stick with the 7.2V NiMh pack as i have plenty of these and relevant chargers. I was planning on attaching some of the foam packing blocks that come in the kit hard up against the bows as there is a nice little notch to wedge it in.
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Some more progress has been made one of the benefits of shift work is i get days off during the week when everyone including my wife is at work so i'm free to do what i want. I finally took the plunge and epoxied in the prop and engine mount i always get a little nervous with this stuff as you only get some many minutes of wiggle room. I test fitted everything until i was confident it could slide everything into place within the 5min window for the stuff i was using. I marked where i wanted to glue with a pencil and roughed up the brass prop tube with a file and sandpaper to give it a good key. First off i glued to top part (#10) on the outside of the hull in and allowed it to dry while i was waiting for that i marked and drilled and filed out the cooling holes in the mount then i attached the motor to the mount and installed to coupling and prop tube. I applied a small amount of epoxy to the area's needed and carefully slid the tube through the opening in the hull and pushed the mount up against the stringer in the hull that it glues too. I then realised that some of the glue had got onto the nut and thread at the prop end of the tube so i had to race up to the kitchen to get some metho to wipe it off. I held everything in place until the glue had gone off and then applied a liberal amount to the tube and where everything disappears into the hull to seal it. I went for the more is better approach here and as it will be under the waterline i wasn't to carefull about how much i heaped on. I've got some 6mm ply that i will use to make the gussets and top strip over the motor mount when i get my hands on a scroll saw
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Start looking for a suitable strip of metal to fit on the bottom of the keel, screw and glue a brass or ally piece to strengthen the whole length and as a rubbing strip. The bit that sticks out will get snapped off IMO. Springers have such a strip that goes right out to the under the rudder. Protects the rudder in shallow water and gives a pivot for the bottom of the rudder post. Are you making a metal rudder ?
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No the kit has a ply one made up of 6 different sized pieces sandwiched around a brass rod then sanded to a "streamlined" profile it does not attach to the bottom piece. I'm planning on using some brass strip or extra ply along the bottom part the provide some strength
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Lots of ideas on rudder shape in the RCGroups Springer pages, flat plates, salmon-tailed, Gurney strips. Built-up streamlined from body-filler (auto)or Milliput (epoxy) on a brass flat plate. Wood might be a tad delicate %) O0 Picture shows a Gurney, flat plate strip on trailing edge of rudder. Works OK but the so do all the others I`ve tried %% {-) Not an F1 boat after all :embarrassed:
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:-)) "Not an F1 boat" Funnily enough one of the main reasons why i'm building this one is to retrieve future faster boats when they go the wrong way up in the middle of the lake
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Good choice, I`ve retrieved Jiant Jaberwock biplanes and Northstar deltas with mine. No F1 s :(( Watcha gonna call it, something German maybe ? %) "Rambo" seems about right O0
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Lol yeah not sure at this stage my missus thinks i should name it the "Jolly Jess" after our Labrador who's always in the garage supervising me when I'm working. But I'll make the final decision later on (Probably go with the wife's as shes the one i have to sneak the large boxes past to get to the garage). Still thinking about the final color scheme as well thinking red hull white superstructure and green decks.
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Managed get some stuff done before i started night shifts. First of i glued a piece of square hardwood butting up along the back of the motor mount I then cut out the gussets and cap strip from an off cut of 6mm ply i found. These pieces were glued to the motor mount using epoxy. The next step is to install the servo mount and rudder tube. When i was test fitting the servo mount i discovered that the hole in the hull didn't line up with the hole in servo mount >:-o . when inserting the brass tube into the hull it came out at almost a 45 degree angle towards the prop. I had to use a round file to widen the hole in the hull to enable the brass tube to hang correctly i installed the rudder temporarily into the brass tube to make sure i had the correct angle and tacked the outer brass tube in with CA. Once this had gone off i carefully removed the rudder by bending the rubbing strip out of the way and pulling it out i then plugged up the gap with two part epoxy. The next step is installing the top stringers and sealing the inner hull with z-poxy finishing resin. I'll also cut out and install some foam into the bow area while i have access. Hopefully by then my ESC will have arrived and i can discover the joys of wiring and soldering.
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More progress made today. The interior has been given a coat of z-poxy finishing resin. While that was drying I made the hatch coamings and covers. The rear hatch coaming needed a lot of filing and sanding to allow the hatch to sit over it properly. Finally I glued the rubbing strips to the edge of the deck. This is acheived by placing tape on the top side edges then flipping it over and on flat surface weighted down to ensure the deck stays flat the strips are glued to the edges. I pinned the edges in to ensure a nice join. There is a slight raise from the deck and strips that will provide a nice glue seal area.
The rudder was also glued together using two part epoxy then sanded to shape using a dremel tool. My mtronik ESC arrived today as well so I'll have to make a start on the wiring now as I want to get all of it installed and tested before I glue the deck down.
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Interesting wooden rudder, I wonder about longevity. Maybe put a thin flat cap top and bottom to help stop delamination of the ply. Loads of gloss paint !!! Put a coat of matt mid grey paint on the inside of the hull , it will show any ingress of water instantly. Looking good, got a name yet ?
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Rudder will be coated in z-poxy then a couple of coats of enamel paint and a few coats of varnish when it comes to that stage so hopefully shouldn't be a problem only time will tell. No name as yet.
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A tip from the USA is to add a "salmon tail" or a "Gurney strip" on the trailing edge of the rudder. Makes for sharper turns they say. End-plates top and bottom seem to be the fashion too. PS I know the washer is in the wrong place on the propshaft
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Managed to complete some small jobs over the last few days unfortunatly i'm back on dayshifts >:-o so i don't get a lot of free time to get into the garage. I got my old man to solder the motor wires on for me as he's alot better then i am with the iron. The main and rear deck hatches have been assembled, filled, sanded, Sanding sealered 2x coats, sanded, then a coat of primer sprayed. I've also assembled the dolphin posts filled and sanded then filled and sanded until i gave up and went and had a beer instead i'll come back to them later. The underside of the deck has 3 coats of sanding sealer applied and i've put the three top stringers into the hull and sealed them. Once i bench test the motor, esc and Rx I'll be ready to attach the deck to the hull.
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Haven't had much time to do anything work and my new Pro boat Blackjack 29 are getting in the way of progress. I've put all the electrics together for a bench test, everything goes together Ok but i just want to confirm one thing. On the back of the motor one terminal has a red mark next to it I'm assuming that this is the positive (+) terminal?? plugging in the wires either way seems to get the motor to turn so I'm assuming this just reverses the direction of the motor? {:-{
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Yes, the red terminal is positive. You might find this way around is also the fastest and most efficient speed.
Ken
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G'day all,
Just a quick note to let you know I'm still alive. Been copping a flogging at work for the last few weeks and every spare moment i have seems to be taken up with other things plus every time there has been warm weather I'm down at the lake with my blackjack 29 %% I love this boat so much fun out of the box. I've posted a link below of a youtube video i made by attaching my go-pro to the hatch. I've got some leave over the silly season so hopefully I'll have a chance to get back in the shed and do some work on the tug. I'm trying to convince Santa's local rep that i need another boat kit for Xmas but she sez i have to complete the tug before I'm allowed to get another >>:-(
http://www.youtube.com/watch?v=AjXn0RqNktE (http://www.youtube.com/watch?v=AjXn0RqNktE)