Skimmer help wanted.

[Keith Garner 1Participant @keithgarner1]

I’m an aeromodeller but always had a good look at the boats section at any model exhibition and was given a copy of Model Boats Nov. 2008. In it there is an article about skimmers and a small plan of the Skimmer 400 published In sept 2007. As my aero club also has access to a pond I’ve decided to build one. I already have the necessary motor/ controller and Rx. I have three queries.

1 Where is the C of G on such a skimmer? I guess about 2/3 back but I would like it confirmed.

2. Waterproofing. Would Solarfim with sealed edges do or do I need to “varnish” the balsa hull first?

3. My Rx has a trailing wire arial – would keeping most of it in the hull with just a short length to say the propellor guard be OK? I see on Utube there is a skimmer with a “mast” arial – is this a special boat Rx?

Any suggestions gratefully received…………..

[Keith Garner 1Participant @keithgarner1]

[LARRY WHETTONParticipant @larrywhetton68737]

hi Keith, have look on model mayhem web page, under ,

beginners start here , you a full page of the skimmer , and other info you are after,

and also my build of fast build hull. Larry……

[LARRY WHETTONParticipant @larrywhetton68737]

hi KEITH, hows skimmer coming on ?………

here is mine now ready for testing……

LARRY

[Keith Garner 1Participant @keithgarner1]

Thanks Larry for your response but I just cannot find the model mayhem site you mention. Can you give me a bit more detail please. I love the skimmer – mine is still in much earlier stages.

Keith

[The Long BuildParticipant @thelongbuild]

Model Boat Mayhem

 

http://www.modelboatmayhem.co.uk

 

 

Link to Skimmer

 

http://www.modelboatmayhem.co.uk/forum/index.php?topic=28614.msg283594;topicseen#msg283594

[ashley needhamParticipant @ashleyneedham69188]

Larry, normally I advocate crew on a boat, but……

 

AShley

[LARRY WHETTONParticipant @larrywhetton68737]

HI ASHLEY just a bad hair day ………LARRY.

[LARRY WHETTONParticipant @larrywhetton68737]

well it WENT quite well , but to much draft took on water ,will add a bit of buoyancy……..

well it is a swamp boat ………..LARRY..

[MzeeParticipant @mzee]

Well folks, I have just posted a couple of pics of my skimmer – a modified Glyn Guest version. Goes like the proverbial clappers and have yet to find somebody to handle the camera. The CG on mine is as suggested by Glynn and that is at the aft end of the hatch. I waterproofed the ‘boat’ by applying three coats of sanding sealer (the first well diluted) inside and out followed by a couple of coats of Duco spray on the outer surfaces. The Rc aerial is fed up a short piece of aircraft push rod tube which is retained in place by a screw fitting (thanks to Unimat!). The ‘guts’ for this ‘toy’ came from my Multiplex Easy Star foamy ‘plane that decided, all of it’s own accord, to make an unscheduled vertical arrival from about 800 – 900 ft – those foamy ‘planes are NOT indestructible!

[LARRY WHETTONParticipant @larrywhetton68737]

hi there veiwed your skimmer, great build , they do go well dont they ,

jUst bult another one using stryrene , made hatch better fit and added a bit of foam up front see this one goes , by the way what prop are you using ?………cheers LARRY.

[MzeeParticipant @mzee]

Hi Larry.

 

Thank you – yep! They sure do go – the acceleration is quite awesome!. As you will have seen, I don;t have any driver figure up front in the interests of reducing weight as much as possible so I can imagine a foam styrene hull would/could be the ultimate in this regard. The prop? Well it is the standard prop that came with the ‘plane; 126mm diameter so I guess it might be a 5 x 6 inch ?? Gives enough oomph that it runs pretty well on the verandah carpet!

 

When I first looked at Glynn Guest’s original specifications my first thought was, ‘You must be joking’. It looked far too small for the power in that motor and I was all for making the hull 400mm LOA. But I’m glad now I didn’t. Also, and having built a couple of hovercraft way back in the ’50s (powered by Frog 150 diesels running on loads of amyl nitrate!), I wondered about the handling and was almost tempted to add a couple of 3mm stringers to so as to give some ‘bite’. Again I’m glad I didn’t as that characteristic ‘sideslip’ is what it is all about .

 

Great fun indeed. My only water is a local dam so my runs are made only early in the morning or when we have a dead calm day but I am pleased that I have the space!

 

Regards,

Robin

[MzeeParticipant @mzee]

Oh! Just re-read the Multiples blurb in which I find that the motor is a Permax 400 and prop a 125 x 110 (4.9 x 4.3 inch). No wonder the Skimmer has remarkable acceleration!

R

[LARRY WHETTONParticipant @larrywhetton68737]

HI KEITH ,rebuilt skimmer , now ready ,build was

quicker 4hrs all together ,

using salvage parts from no 1 build……… but but must get smaller pilot….

CHEERS LARRY pics will follow….

[Dave MilbournParticipant @davemilbourn48782]

Larry

My Skimmer was built to Glynn’s plan, went like greased weasel poo, and used a Speed 400 7.2v motor, a Graupner 2-blade 6″ x 3″ airscrew and a 6 cell AA-sized NiCad pack. I reckon your battery pack is much heavier than this so I’d suggest a power transplant., using either NiMH AA cells or maybe a 2-cell LiPo pack (7.4v).

Hope this helps – oh, and slowing down a bit to take corners is definitely a good idea!

Dave M

[LARRY WHETTONParticipant @larrywhetton68737]

skimmer 2 in styrene with stowaway………….ANOTHER FAST BUILD..

no balsa to seal ……….LARRY...

[LARRY WHETTONParticipant @larrywhetton68737]

hi DAVE thank you for info on power pack , swamping the first skimmer did not help.

cg ,i will have a 7vt pack in this more water tight skimmer ……..

please to let you no anthouther swordsman is planed this year twice size with twin screws on 550 motors what do think cheers LARRY..

[MzeeParticipant @mzee]

Nice one Larry – I like the ‘pilot’ and it is kinda more mass-friendly that your previous size-challenged one!. BTW mine has a 7.2V 1400maH NiMH battery pack which when shoved right aft brings the CG almost exactly 1/3 the LOA measured from the stern. As Dave mentioned, one does need to throttle back a tad when cornering. Having been a tug modeller for ages I decided a year or two back that I’d like to have a ‘toy’ that had a little more ‘action’ and began to build a RTTL – then I had to put that aside as it was taking up far too much time and I had a load of scale static dhow and outrigger canoe models to finish. Enter the Skimmer – I can justify the time and have fun as well and for no cost since the bits an pieces were right there in my TBUODB (‘to-be-used-one-day-box’).

 

I like Dave’s graphic description of the speed of his Skimmer – not having weasels in this part of the world I leave it to the imagination!

Robin

[Author]

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