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Author Topic: 1/8 scale hydroplane 'Atlas van Lines' build  (Read 41325 times)

Ramon

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1/8 scale hydroplane 'Atlas van Lines' build
« on: July 12, 2009, 06:45:06 PM »

Hi All,

Those who’ve followed the ‘Huntsman’ thread will know that I have returned to model boats after a long thirty plus year lay off. Just before circumstances led to the decline in interest in the ‘70’s I was very keen to building a hydroplane – not sure what but it would probably have been from a Dumas kit. This was as a direct result of not being able to ‘keep up’ with the OPS 60 powered boat I had built around the 30 metre Naviga triangular course we had laid out. I took to just running the boat flat out in a straight line and have to say got a big kick out of doing so especially when the pipe ‘came in’.  I had made a tentative start on an outrigger for a Merco 35 but it never got past the basic body before work took me to Ecuador (Now you have to appreciate that's not exactly renowned as a haven for model boaters!) and all my ideas and ideals faded away.

Last year when I saw the boats run by the guy’s at the local water that desire to build that hydro immediately returned especially when I realised one of the guy’s – Martin, Mayhems’ ‘Mr Fid’ - had the same interest.

Something more ‘sedate’ had to come first hence the Huntsman but to be honest all my effort really went into finding out about hydros to wit the computer is as full of as much info and pics as I could find. It quickly became apparent that there was much more to choose from than Dumas. Not wanting to be seen as running before walking however I’ve kept the build of my first hydro well in the background but the recent post by Adam on his Miss Circus Circus  has led me to ‘declare my interest’

With the apparent interest shown in the Huntsman build I thought that this may also be of interest to those who have similar aspirations as well as hopefully to hear from those far more experienced when things appear to be going off track. This then is a build thread of my first attempt, albeit part retrospectively, based on the info I have found and the help I have received from others on this and the 'R/C Universe' forum’s.

That initial search of the net produced  a free downloadable plan on the Astec models site for the 1977 Atlas van Lines ‘picklefork’ hydroplane. This was/is available in several scales though all are for electric power.
I began by contacting a copy shop who just said “email the file and the rest is easy!” Two days later I received two sheets of full size 1/8 scale drawings for the princely sum of seven pounds! The original drawings appear to be drawn by CAD and have proved extremely accurate.







Construction began by making card templates from the drawing using carbon paper and then transferred the shapes to the ply. All ply is 3mm except the engine rails and inner transom which are 6mm



These were then cut out to complete a kit of parts to build the basic frame work the main 'sides' being two laminations the inner of which gives the profile of the tunnel



They quickly and accurately assembled to produce the basic framework. Thought was given at this very early stage to the fuel system but more on that later.



Let's call that enough to start with. Hope it's of interest and will prove useful to someone somewhere.

Back soon - Ramon


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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #1 on: July 13, 2009, 10:33:20 AM »

Nice to see you started a thread on the build Ramon ,ill be watching with interest your work looks very clean and precise  :-)).Keep the pics coming  and good luck with it.Good tip on the source to have plans printed,might need to use that place myself.
Mart
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Ramon

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #2 on: July 14, 2009, 10:59:48 PM »

Thanks for the compliment Mart

Managed to get into the workshop for a while today, even got some paint on the H--------------n - before it rained :((

Never mind here's a few pics on the AvL build to cheer things up :-)

Before work on the construction began a simple building jig was made from Contiboard. Two outer edges were cut off another piece and glued parallel with each other the same width apart as the tunnel. The two sides and the front and rear formers were used as an aid in setting the width. The two white faced outer edges of the rails were simply stuck down with thin cyano and it has proved more than adequate however the next one will have much deeper rails to allow for temporary fitting of the strut and rudder etc. during construction. The small ply patch is a front support for the side frames (both sides)



The parts were dry fitted on the jig to ensure alignment then the gluing began. It was decided to make two 6mm engine rails the width of the tunnel apart and to glue the sump strips to these from the outside - the hull is off the jig and laid inverted across it on the latter op.







The tunnel bottom skin being installed with the hull  now fitted inverted to the jig at the rear and supported on a spacer at the front. The sponson side rails were fitted at this stage and small 'fairing' blocks of hard balsa added.


Turned back on the jig for a check and dry fitting of engine and fuel tanks but more on that later.



Hope this is of interest - Ramon
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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #3 on: July 14, 2009, 11:09:38 PM »

Loving your work Ramon,very clean and precise you put me to shame  %).Love the fuel tanks too,ive been thinking about using one of those allumium drinks bottles you can get them in pretty colours too  :-).Keep up the good work mate im def interested.
Mart
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Ramon

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #4 on: July 16, 2009, 11:25:18 PM »

Mart, again, thanks for your compliment.
It is nice that there have been quite a few similar remarks but this is not about putting anyone to shame. I just feel that sharing what I am doing with others is so beneficial to all concerned including myself. I have had such informative and immediate feedback on questions – something that you don’t get writing for a magazine for instance (no, obviously haven’t done it for boats but yes, you probably guessed it, on the odd occasion for control line aircraft!) – that that is what makes the ‘forum’ such a modelling asset.

Enough, he said – the model………



At about the stage of the pic above I posted on the R/C universe forum and received some timely advice. This was with regard to the C/G position which I was informed should be no more than 2” aft of the sponson transom. The advice was to lighten the boat aft of this point and move the fuel tanks forward. The mass of fuel is now over the C/G point but obviously as it drains it will load toward the rear ends but the C/G shift should be minimal due to fuel usage.
I had intended to make each side from the transom to the sponson a water tight compartment but was assured that no matter how water tight I thought it would be water would eventually get in. On the basis that if it did it probably would not get out as quick a decision was made to cut out holes in between the formers to not only to aid lightening but also to allow the air to circulate after a dunking! Holes were cut in the bottom of each former to allow water to drain through to the sponsons and two suction baler tubes were later fitted to allow water removal using a syringe.





The engine is hard mounted on ally plates let into very hard Beech bearers. The engine was bolted to the bearers and then the whole was epoxied in place. This ensures the crankcase is not distorted by pulling down onto misaligned bearers. The rails were a bit two narrow to get in a normal ally mount, the width dictated by the width of the tunnel sump. I don’t think this will be a major limitation, all my previous boats had hard mounts and I can’t remember any problems as a result – any thoughts anyone?
I have offset the engine slightly – all my previous boats showed a torque induced ‘twist’ or ‘list’ to the right and this may, hopefully, help eliminate or reduce that tendency. Besides the plan shows it but agreed it is the other side of the centreline! but it is electric!!



Stringers were added to the outer edges to give the 'non trip' sides a better gluing area



With the 1/16 ply non trips added it began to look a bit more like it should

.

That's about it for now, still quite a bit to go before catching up to it's current stage.

Regards for now - all comments welcome - good or bad - Ramon


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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #5 on: July 17, 2009, 10:39:49 AM »

Hi Ramon im loving your work shes looking great and i like the idea of been able to drain any water from the sponsons thats a good idea .A friend of mine drills a drain hole in the transom sponsons and covers it with tape or plugs the holes so he can remove and drain.Im not so sure about a hard mount for the motor id try and fit some kind of rubber mounts in there somehow.Im sure with your skill you can come up with something  ok2.
Mart
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Baz2

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #6 on: July 17, 2009, 01:33:14 PM »

 
   Hi Ramon
       
         I am new to model boats so decided to join the forum to learn from other members building experiences.

         I was impressed with the parts you cut out from the ply, I would be interested to know if you used a bandsaw
         or a good old fashioned modelling knife.

         The boat looks great, keep up the good work, I shall follow build with interest.

        Baz2
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ids987

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #7 on: July 17, 2009, 02:25:30 PM »

Hi Ramon,

Truly a joy to behold. If I ever managed to build anything that well (and I never will. I haven't got the skill, patience, time.... the list goes on), I don't think I'd want to run it, and I get most of my kicks from the running. The little touches and forethought speak volumes too.

I hate to say it, but I would personally prefer to see rubber mountings as well though - were it me.
Without, I think noise, and the vibration itself will be problematic. If the noise isn't a problem, I think vibration will be - even if not immediately.
The threaded rubbers come in quite a variety of lengths. Even the shortest should be better than none. Vertical rubbers could perhaps save space in the horizontal plane. I have also seen riggers, where rubber grommets or blocks of some kind are inserted in the sides of the tub, and bolts pass through these to the engine mounts. I think that system is used on at least some of the Eagle SG family.

Must admit, with normal rotation, I always thought offset to the right was the way to go for torque counter-reaction, but I guess there are a few factors at play, and may be different in a Hydro. The most common argument for right of centre offset, seems to be that there is then more boat to lift left of the engine, than right of the engine. Having sponsons, and the right hand sponson (presumably) having water to push down on, may change this though. Obviously the balance point also moves left with the engine. Turn fins also generate lift (sorry, stating the obvious again). Riggers with large turn fins (especially if they are not very sharp), can tend to lift the right hand sponson at speed - even against the torque. Am I getting warm anywhere in there ?

Ian
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andyn

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #8 on: July 17, 2009, 02:55:26 PM »

All the current Eagle SGX's and I think all the Firefighters have the rubbers going out through the side of the tub :-))

Straight mounting an engine, especially one as big as that, will create so much noise and it will shake joints apart. I've been there done that with a small catamaran...
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Ramon

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #9 on: July 17, 2009, 06:16:15 PM »

Hi All
So pleased to receive this valued input - I am taking it all on board and will reply to it all later
In the meantime, really, a big thanks.
Ramon
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Ramon

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #10 on: July 17, 2009, 10:28:31 PM »

Hi guys, back again but with a bit more time to respond to your thoughts.

First though - Baz - All the parts are cut using a small Burgess BK3 bench mounted bandsaw. I don't know if they are still made (mine's twenty five years old!) but I'm sure there must be something very similar and probably now much cheaper though this one was not that expensive. I have a twentyfour teeth per inch metal-cutting blade mounted all the time. I find this ideal for cutting the wood sizes mainly dealt with and it will handle quite thick chunks of metal too if you take it slowly. I always cut just outside of the line and finish with home made sanding blocks. I do have a linisher but rarely use it. The blocks are easily made using Contiboard off cuts and double sided sticky tape and 60 to 80 grit for roughing and finer grit down to 320 for finishing. I have built up a collection of sizes and grits over the years, always reluctant to bin them some are very well worn but still have a use. You can 'sand' very smooth straight edges with longer versions :-


Regarding the engine mounts - Hmmm! I take on board all that you say and admit that it looks as if my thinking on this is abit out of kilter with current thinking. I have mounted the HP60 in the Huntsman on rubber supported ally mounts but as said felt I didn't have enough room. Having taken a good look today I think in hindsight with a centrally mounted motor I could have done. I don't think that it would be a viable proposition at this stage to try to change it - too much cutting involved - so will leave it to see how it works out. Though it appears that noise is not too great an issue where this will be driven I am concerned by Andy's comment - this side of things I didn't consider at all. Resonnance from vibration can be a real problem though. The manner of mounting is exactly how I mounted motors in my aircraft where vibration, or rather lack of, is just as important but as said before those motors were running at a much lower rev bands. However I would say that most of the time hard mounting dissipated any vibration through the airframe much better than those aircraft with motors resilient mounted.
I'm afraid my decision to do this is based on previous experience and obviously not current practice. It will be interesting to compare the two boats over this matter and I'll let you know how this turns out.
As a matter of interest do boats have a decibel rating they are expected to comply with as aircraft certainly do. How do you measure it with boats? ie with aircraft it is from all four points 3ft off the ground at 7mtrs distance.
Andy can you explain a little more descriptively about the 'mounting through the side of the tub' please I would be interested to see how this is done.

Ian, as always thanks for another in depth reply. Again I think I have looked at this from an aircraft perspective - to counteract torque the side thrust is normally set to the left. I can see what you are saying, but I have assumed that having the greater mass to the right of the engine will mean the torque has more to push against. Boats at Bungay are required to run clockwise so 'right hand' all the time which in itself applies this right hand pressure. I'm not so sure of my reasoning now thats for sure but again only time will tell on this one too.

It will be interesting indeed to see if this ole man's thinking can still cut the biscuit but by the sound of it I doubt it!

Progress is ongoing the first top skin was glued on this evening can't wait to get the clamps off tommorow

Thanks again you 'lovely lads'

Regards - Ramon








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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #11 on: July 17, 2009, 10:49:32 PM »

Ramon sound level is measured in decables and the law says 82 is the limit i believe?.I really hope you do add rubber dampers to your setup its not that hard to do,use ali angle bolted to an ali plate to mount your motor to then add the dampers between the ali angles and the wooden rails.Vibration in a boat will quickly loosen every nut and bolt and also pull joints apart at the speeds this thing will be doing.As regards planes and boats air is soft water is hard ,vibration in a boat is magnified trust me.
Mart
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andyn

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #12 on: July 17, 2009, 11:30:57 PM »

The limit for both OMRA and MPBA is 80 decibels, this is done by the sound meter being at 90 dergrees to the running boat on a straight, at 10 meters distance.

I've had a wooden catamaran powered by a .16 (that I didn't make by the way) that shook all the glue joints apart. Ive also seen a Perkasa powered by .35 sports engine that actually took the mountings and propshaft out of the boat.

Look down the side of this hull, next to the engine you will see two blue bolt heads. These are the ends of the rubber mounts. The engine itself is mounted on two right angled rails, which are bolted to the other size of those rubbers. This is very common practise in Outriggers, in fact I think just about every wooden hull uses this method. Carbon ones are done differently.

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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #13 on: July 18, 2009, 12:04:14 AM »

cpl more examples last ones mine in the  first comet t boat
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Ramon

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #14 on: July 18, 2009, 10:57:22 AM »

Excellent, thanks Andy and Mart I can see exactly what you mean. I have to admit it could have been one this way.

Just been out and took those clamps off - very pleased. Had another good look to see if I could do what you suggest but it really would involve such a high degree of 'intrusion' that I don't really want to try at this stage.
I shall have to live with it now but will not go this way again. Just hope the noise is acceptable.

I'll try to get a further posting on the build tonight.

Regards for now and thanks again - Ramon
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andyn

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #15 on: July 18, 2009, 02:28:37 PM »

The rubber mounts (small type) are 6/8" diameter, could you not drill 7/8" holes through the ply itself and contain the rubbers within the wood, bolting them to an ally plate on the other side of the ply. Something like this:

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Baz2

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #16 on: July 18, 2009, 03:51:26 PM »


   Hi Ramon

     Thanks very much for the prompt reply and the information which is very useful
        Thanks once again
 
                  Baz2
 
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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #17 on: July 18, 2009, 05:09:23 PM »

Ramon this would be how i would do it.4 bits of ali angle and 4 rubber feet and an ali plate to mount your motor onto.
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andyn

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #18 on: July 18, 2009, 09:05:22 PM »

The bottom of the crankcase looks a little too close to the hull bottom to be able to do that I think.
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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #19 on: July 18, 2009, 09:32:21 PM »

Even if thats the case he can flip them the other way up so the motor is hanging from them either way works.Thats what i had to do in my Rocket hydro i flipped one set to get her lower.Id also consider usaing a flexable cable instead of a solid shaft that way he has more options as regards motor posistion .
Mart
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andyn

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #20 on: July 18, 2009, 09:55:53 PM »

Also If you used a strut or a stinger (preferable) you can alter the thrust angle of the engine. However the plans do detail a flexi shaft, I think the tube in the pic is the stuffing tube, I'm sure Ramon will enlighten us on this :-))
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Ramon

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #21 on: July 18, 2009, 10:27:21 PM »

Hi guys,
I have to say I can't get over your interest in helping me here, your effort on my behalf Andy and Mart and Ian is much appreciated.  :-))
I have read all you've said several times but have to say it's really a bit too late in the day on this boat to do what you recommend. You may be misled by the pics of it above but remember these are retrospective and the boat is a lot more advanced than they show. Please - don't take this as I'm not listening, I am, but I really don't think I can take up your advice on this one as it now stands without doing some severe cutting about. Here's a few pics of the installation as of tonight - I'm sure you will see the dilemma.








The fuel tanks are within 1/2" or so of the rail outside face each side and the top skin on the left is now very firmly glued down making access very difficult. All the parts are bonded with epoxy.
No, I guess I'm stuck with this as it stands {:-{ and can only say that whilst I take onboard everything you are saying my previous boats did have hard mounted  engines and can only reiterate that I really don't remember any real stress problems due to vibration. That does not mean I don't think I won't this time merely that's how I remember it. That original OPS 60 was mounted to an ally plate bolted in turn to beech bearers that were bonded to the F.G hull.

I will pay very close attention to engine /shaft alignment (It is going to be a flex shaft by the way - it's just pushed into a temp coupling there to hold the flywheel on to get the slot in the hull aligned) and balance everything I can (new flywheel for a start!).
I do appreciate your advice, my main concern now is your reference to noise but can only wait and see on that one. One thing's for sure my next one (and yes there will be a next one!) will not be built like this.

Hope you can see my situation

Thanks again - Ramon
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andyn

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #22 on: July 18, 2009, 10:49:55 PM »

I have to say I can't get over your interest in helping me here, your effort on my behalf Andy and Mart and Ian is much appreciated.  :-))

We just want to see it goooooooooo......
 :-))
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martno1fan

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #23 on: July 18, 2009, 11:03:42 PM »

No worries Ramon so will this be a transom mounted strut setup or true scale and have the prop under the hull ?Will it be angled down or parallel like a surface drive setup.Im asuming like atraditional submerged setup? in which case a solid shaft would be best because a flex needs the bend to avoid cable whip.Excuse my questions as i havent seen the plans yet lol.by the way Andy you cant use a stinger on a hydro as the prop sits too low under the transom  ;).
Mart
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andyn

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Re: 1/8 scale hydroplane 'Atlas van Lines' build
« Reply #24 on: July 19, 2009, 01:20:48 PM »

Andy you cant use a stinger on a hydro as the prop sits too low under the transom  ;)

Ok then :-)) Not a Hydro man myself, just prefer stingers to struts O0
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