Todays Boating

[ashley needhamParticipant @ashleyneedham69188]

Cheers DM . Sigh… A pair of juxtaposed heads so they face the same way either side…. BUT…

.good suggestion….A head and a Mr Whoppit….good spot, the sort of little detail I like!.

Ashley

[Dave MilbournParticipant @davemilbourn48782]

. Sigh… A pair of juxtaposed heads so they face the same way either side…. BUT…

Bravo! ……although K7 was strictly a single-seater, wasn't it?

Yer've gorra gerrit raaht, m'duck!

DM

[ashley needhamParticipant @ashleyneedham69188]

yeah…I need one head pointing forward on the left of the flat perspex and one on the other so they both look forward!,,,,

OR it might be I can paste a double image on just one side?

The jet efflux duct is in place now so all is set for unlock down and a float.

Cobb proving a bit tricky and whilst waiting for more bits I have looked at using my 2 and 3 mm liteply, and found a Jetex design!

Yes, Jetex… "Swordfish". Not an exciting thing, but should be jolly light (1 oz suggested) and who knows??? The box for my edf says 150gm thrust on a 2s Lipo, effectivly.

Not an expensive design (2 shillings) and I have enough ply. OBVIOUSLY it will be double plan size, and I will try to build roughly to plan. I have some ideas if the floatation is insufficient, or indeed it just wont come up to the plane. If it doesn't work I will not be putting a brushless fan in as it would simply take off.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Ordered some mini servos for Swordfish, and some Balsa cement!!!!

Like using balsa cement, and it dries nice and hard and has good gap filling properties. I have been trying to suss out the mods needed for putting the gear in the hull (as the original had an enclosed hull) but have given up, too many variables, and second guessing where the stuff might go is not always a good idea. Obviously a hatch will be needed and that would appear to be inside the cabin, therefore the cabin will have a large hatch in, and will be roof-less…having a detachable roof. Beyond that?? who can say.

I shall be using ALMOST balsa (lite ply) and as the original was advertised as building to 1oz, I shall be looking to build to 2oz as mine will be slightly less than twice as big!!

Say….120g thrust (having checked the box), 77g for the edf, 100g for the 2s and 2oz for the hull, I should be on to a spritely performance??

Ashley

yes, I DO know…… Perhaps about 6oz

Edited By ashley needham on 23/04/2020 18:08:53

Edited By ashley needham on 23/04/2020 18:11:08

[Ray Wood 3Participant @raywood3]

Hi Ashley

Did you see my suggestion of a edf 50mm challenge at you lake next year, I put it in the I Osprey thread, I should have put it here!!

Regards Ray

[ashley needhamParticipant @ashleyneedham69188]

Hi Ray, yes I did see that! Its certainly a thought, but I am not sure it will get a universal welcome??

Trouble with challenges is that unless you simply build, do the challenge and then scrap it, it still costs more or less the same to do that or make a boat that you really want to make! However, eventually we might convene and discuss the merit of the idea (hopefully)(meet again, that is)

Swordfish sides made and glued to several bulkheads, and of course is wonky! 3mm lite ply is atrocious stuff ….and the 2mm thick bits I cut for skinning are really unusable. I shall have to use 0.8mm and 1.5mm ply. The accent is on lightness so I trying not to add too many braces, and of course there is the thorny problem of access and where to put the battery/allow maximum room to allow battery to be repositioned. Checked a while ago and it twists about 4 or 5 mm e-e, which is not too bad over 450mm length/170mm breadth. Hopefully as I add further structural items I can bring this right down.

Ashley

[Ray Wood 3Participant @raywood3]

Hi Ashley,

I'm not a fan of liteply as it distorts so much !

The edf's for boats are something new to experiment with,and the new generation of brushless fan units. as my As my old design Wetjet with a Womotech 480 was too heavy for much speed 😕

Regards Ray

[Dave MilbournParticipant @davemilbourn48782]

Liteply – I have used it for a lot of years and never had any problems with it warping or distorting. Apart from the models I did for Model Slipway – which were all GRP and styrene – it's been the basis of every model I've designed since about 1980. Those range from the little Fairey Huntress 23" boat to the T240 R/C model aeroplane, whose wingspan is 2.4m.

I guess it's down to how you use it. Store it flat and dry; use aliphatic resin glue or Slo-Zap, and make sure you sand it and fill the grain before painting it. Buying it from a reliable source also helps, but I've always used SLEC so I've no idea what else is out there masquerading as Liteply. Birch ply has its applications in my boats e.g. motor mounts, but I find it's too heavy and resistant to bending for most uses.

Takes all sorts, I suppose…

Dave M

Edited By Dave Milbourn on 24/04/2020 19:22:55

[Ray Wood 3Participant @raywood3]

Hi Dave

Your right the SLEC stuff is well behaved, I must have been unlucky with the odd sheets I've bought at shows & not stored it flat 😕

Regards Ray

[Tim RoweParticipant @timrowe83142]

My modelling would come to a grinding halt without Liteply (SLEC Stuff) and Aliphatic.

In fact my modelling is coming to a grinding halt as I am running out of Aliphatic

My favourite is Deluxe and I can't find it on the Island Boo Hoo

Tim R

[Tim RoweParticipant @timrowe83142]

Continuing on the Liteply theme it is fine if it is only twisted or curved in one plane as it should be able to built out.

Coming from mainly model aircaft building where lightness is crucial, I do think our boats are mainly overbuilt but I suppose it saves a bit of ballast.

Tim R

[Dave MilbournParticipant @davemilbourn48782]

Coming from mainly model aircaft building where lightness is crucial, I do think our boats are mainly overbuilt but I suppose it saves a bit of ballast.

Tim

Couldn't agree more. I'm currently using De-Luxe's Speed-Bond adhesive for liteply structures. Speed Bond It's a PVA-ish thing but has a faint solvent smell and sets up very quickly.

Dave M

[ashley needhamParticipant @ashleyneedham69188]

The big sheet I cut the sides from was moderately straight, however I have a feeling the sun did for the cutouts on the bench outside! Although the sides are slightly bowed, that will be taken care of when the bottom skin is applied.

I am giving balsa cement a try, just for nostalgia sakes on a vintage design. It’s a once only tryout.

It is difficult knowing where the battery might want to be positioned and therefore where I can add balsa braces internally. I will be using a 2s Lipo which is half the depth of the rear portion of the hull, so I might allow a run down the middle of the boat with full depth balsa sides and have few diagonal braces off that?

I am conscious of the weight, my brushed GWS edf is not powerful unlike the FMS 50mm unit just received from George at 4-max which would likely send it into orbit!

Ashley

lipo

[Ray Wood 3Participant @raywood3]

Hi Ashley,

I have a couple of those FMS Fans cute little devils aren't they, I have one in my Jet Provost and the other is spare for a boat ??

Had you thought of angling the jet pipe down at the rear to see if you get extra thrust from the water's surface, maybe completely wrong but worth a thought, the water must give some resistance, obviously not an issue for an aeroplane.

Regards Ray

[Tim RoweParticipant @timrowe83142]

Hi Ray

Could be an issue for my seaplane

Tim R

[ashley needhamParticipant @ashleyneedham69188]

Getting these things on the step is the issue, and one off the water a bit you get the full benefit of an air drive. Someone told me you need about twice the power in a prop or edf compared to a water prop?.

Tim..seaplane! Talk to me! I have yet to test the Walrus properly as the days were too windy. Having hopefully cured the straight line stability with a fixed rear rudder, we are banged up..and all this wonderful weather.

Bluebird exhaust slightly downwards, just a tiny bit. crusader down by a reasonable amount, Swordfish parallel to the rear but that sits downwards at least to start with. Is this all as it should be? Won’t know for likely months yet…three air boats all untested !

Divine intervention overnight for the Swordfish wonky liteply. Having weighted the frame down with a 3mm packing piece under one corner overnight, the frame now seems be virtually square, and the sides have also straightened up. Needless to say some work on it today has been done in the shed.

Now I have the frame to play with I can see how to proc Ed regarding access, battery location etc. A thin ply mounting ring has also been made for the edf.

Ashley

[Ray Wood 3Participant @raywood3]

Hi Ashley,

Interesting balance between thrust, weight, wetted area and luck 😀

I think trial and error maybe the only way ! The sketch book is out & Depron is in stock 😂

The Walrus high thrust line is interesting because you want speed but not flight, some outburst ??

Regards Ray

[Colin BishopModerator @colinbishop34627]

The frustrating thing in current conditions is that you cannot test and experiment.

At least with the sort of scale models I build I can fit the whirly things on the back and test them in the bath to give a good indication of likely perfornance.

Colin

[ashley needhamParticipant @ashleyneedham69188]

I don’t hold up much hope for scintillating performancefortheSwordfish, it’s just interest in making something “vintage” looking and of course obscure. Likely the original actually went quite well (for about 5 seconds).

I might even leave it in “plain doped balsa” finish !! I have pinched your “outrigger rudder” arrangement , Trevor , for the rudder but have used a bit of dowel rather than carbon fibre (I think it used to be a paint brush handle!).

The bath test can be misleading sometimes with water sloshed everywhere and raising your expectations but not quite delivering the goods on the pond. hOWEVER…it does give As you say Colin, a likely indication and is better than nothing, especially at the moment.

Ashley

Edited By ashley needham on 25/04/2020 22:33:48

[Richard BarnettParticipant @richardbarnett67129]

I gave up on using the bath for testing years ago, too much grief from my beloved + my boats usually won’t fit, it seems as I’ve got older my boats have got bigger? Must be my eyesight to blame?

Kiddies paddling pool is the way to go, filled to the top so you can see where the plimsoll line needs to be, doesn’t matter about spillages and waters the lawn when your done! Not a good idea if you live in a flat though 😂

Ricky ye pirate 🏴‍☠️

[ashley needhamParticipant @ashleyneedham69188]

Cracking on then, nifty sliding mount made for Cobb, sundry stays and rudder apparatus for Swordfish. Projected weight for Swordfish…..500g: Arrived at by bunglng the frame so far, about the right amount of 0.8mm ply to cover Lipo, Fan and a heavy esc to stimulate the light esc/rcvr/servo. a bit disappointing?

However the battery is 120g or so and the fan probably the same, so the actual boat should be very light. Nowt you can do about the bits (battery/motor and rc gear) without spending big on small, if you know what I mean.

Never tried all these other glues DM, one day perhaps….

Ashley

[Colin BishopModerator @colinbishop34627]

Bob has been using wallpaper paste – I bet that works great on hardboard…

Colin

[Ray Wood 3Participant @raywood3]

Yes he has 😀 it's really good On wallpaper !!

Regards Ray

[Dave MilbournParticipant @davemilbourn48782]

Never tried all these other glues DM, one day perhaps….

The world is your lobster, Ashley……….

DM

[ashley needhamParticipant @ashleyneedham69188]

Ignoring the SCURRILOUS comments…

I have looked all those wonderfulglues and thought about buying some to try, but for what I build, I am happy with superglue, epoxy and PVA. Perhaps if I were building something nicer (like a speedboat) which required a finer level of either detail and/or finish or having a more demanding level of construction/fiddly bits I might buy better.

So saying..hopefully my balsa cement will arrive today and after greeting the postwoman at a 6 foot distance, using vynilgloves to handle the package, putting on my mask to open the package (outside) and THEN washing the tubes for 20 mins with soap….I can get on with the Swordfish.

Ray, a Depron Swordfish would be the way to go undoubtably, you could do a really light hull then. I have plans digitally, however there are probably better designs to use for an edf

Ashley

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