I had a good building weekend - not only forging ahead with a my working Brig, Volante (too big for a footy), and NeoNao, (too sillly for words), some Razor hulls for learning purposes, and well on with this little fellow which is to a large extent Experimental.
If I am honest EVERYTHING I do has a large element of Experimental about it, but I love surprises.
Hull - expanded polyethylene - low Melting point
Transom, bulkhead, fin - ply from fruit boxes
Rudder - 1/32 ply core, 3/32 balsa each side
Will have large McCormack rig and serve as my trial horse for the rigs
We use a EPE packing strip which is square in section (as pic 1) and it occurred to me that A) its free, and B) there is a footy in there trying to get out.
The only glue that I have found so far to work is hot melt - and I can report that it does exactly what it sez on the tin - it is hot and it does melt the foam.
So I allow it to cool a little and apply with a spatula
I’m hinging the rudder at present - I have tried r/c hinge points - but these are not free enough, taken Gary’s advice, and may try sewn hinges tonight (old control line flyer)
Deck will be 1/32 ply, servos mounted thru it and gluing on the deck will eliminate the starved-horse look (hopefully)
Has anyone any gluing suggestions for intractable plastics?
I expect Litefoot to be a light and light-air footy, along the lines of Moonshadow (but with much more research, calculation and science thrown in).
Hence the fin is a single thickness of fruit box ply - about 1/8 thick. I confess that I did review my stock to find a bit with clear grain that appeared fairly stiff. It is 50mm wide and, funnily enough, a foot long
The fin, rudder and transom have had two coats of acrylic varnish and the deck will get the same when attached
Stop Press - I have been angussed so Litefoot is 123 - memorable or what
No-one can say I don’t listen to the experts - Barry completes his beautiful boats before generating fin, bulb and a CG.
I don’t do it, but I really do listen. I have a cutoff length of lead-in-copper bulb, and this will be the starter for ten - it will gain pointy ends in balsa or blue foam.
Now all I have to do is to liberate some little servos…
Thinks, I have several at 3.3 gm, and a couple at 1.5gm. How light is light?
What is more the 100th UK Footy since I became the National Registrar just on a year ago.
Incidentally, what happened to you today was not strictly being angussed. Being angussed consists of sitting having a nice, innocent hoby project and suddenly being accosted by this talkative ogre who tells that you will register your Footy, that you will give up family and friends to go to open meetings in strange places, build more Footys etc. Further, the ogre tells you it will be Fun.
What you are suffering from is PASS (Post Angussing Stress Syndrome). In this condition you yourself take the role of ogre and persuade yourself of all the above things. Cures are very rare indeed. The most severe victim is believed to be Keven Jackson of Burnley, Lancashire. It is generaly belived that he is beyond hope.
Note Another condition AIFF (Auto-induded Footy Fanaticism) appears to have similar symptoms to PASS but not to require preliminary exposure to angussing. The cause is unknown but the outcome is generally similar.
I have had my main condition diagnosed as DFG* with complications.
*Delusions of Footy Grandeur
Like the conditions you mention is is of the pedo-obsessive group,
whereas angussing is oral/aural and acts directly on a little-known, and usually dormant (in men) organ of the brain which usually makes humans coo and cuddle small amimals.
Meanwhile back at the plot I will sew a hinge today and hang that big oar on the transom and then attach deck. I am tolerably sure that double-sided tape would attach the deck - and that sounds more controllable than hot-melt
IMHO the place for the mandatory 4 AAs is as low as possible in the bilges - so Razor phase 1 had them soldered as 2 cells end-to-end each side of the keel.
One of the cells was bad, and in the interest of surprise management I have made tubes to house 2 cells each, and I expect to use Alkaline throwaway cells.
Not so much to get the 6 volts, but because they are reliable and high capacity
My power 2ubes are now finished, and will grace Razor phase 2 - velcroed to the skin each side of the keel.
Anything built-in will go wrong, anything that can be removed, serviced and replaced won’t - or at least its not so significant
Managed to get a evening of build on Litefoot - still no prizes for precision or elegance but if I prevail it will be by causing the opposition to die laughing
I am told, but find it hard to believe, that PU glue sticks polyethylene foam - I have tried it and cannot yet tell if this is true or if the effect is mainly mechanical (expansion into the space).
However, servos selected, deck on, rudder made, (using Gary principles) and
test floated with 120gm bulb. Nicely buoyant, but without batteries.
Mac Rig planned and a couple of trial bends made - I have used approx 16G wire as I seem to remember this being mentioned as a starting place - it seems enormously heavy and stiff but I will continue.
I’m contemplating attaching the mast and boom with heatshrink - any views?
Sail will be something light and flexible that comes to hand at the sailmaking stage.
I can only promise that it will not carry the class designation “argos”, (as I have no plans to travel to the Euxine)
Progress pics attached - sorry about the quality
Comments on rig proportions, angles gratefully accepted
I love your boat, Andrew,
It’s got foam floatation built in! Plus an interesting colour scheme to boot.
Since you mentioned using heat shrink… Have you given thought to encasing the hull with heat-shrinkable plastic? Not the airplane wing covering type, but the kind used to wrap pallets of food. It’s like a custom-formed water-tight tube. You may be able to eliminate sealing the hull, and may even be able to be a part of the structure itself (I’ve seen a 1M built of balsa formers with a monocote skin.)
Love your thinking, tomohawk
Leads to another thought - have a female mould and foam PU into it, or silicone* so it would be solid foamed closed-cell material with built in skin!
- I have learned how to foam RTV silicone - I can be persuaded to tell, but don’t want to pontificate more than I do already.
Colour scheme is as it comes - its easiest just to like it!
The deck /hull joint is double sided tape and was not a pretty sight - hence the red trim tape.
Your idea about the foamed PU in a mold sounds like the German rubber method. I’d ask you that after foaming the mold, could you bag it all and apply vacuum?
Don’t forget to apply decals, paints, or colored silicones to the mold for decorations before foaming.
You could,but yhy would you? The Pu or whatever foam would have a skin with the finidh of the mould - see your car dashboard for the effect - so the surcace is already finished.
It would be possible to also make voids for the radio, servos etc, if not too easy.
Litefoot progressed last night , this morning and the trial MacRig is complete and fitted.
It went better that I would have believed possible, but will it work?
As I went to sleep I have just one slight snagette - I cant fit all the equipment into the boat
Ever the optimist, I regard this as a mere challenge to my creative spirit and have left it to mull until I get to look at things tonight
Pics of Litefoot as of 6.00 am today follow when I can winkle them out of the camera
Said to be worth a thousand
What do I know, but this rig looks a little bow-heavy to me - too much area forward
If this happens in practice I can bend the mast aft but them my lovely hot-iron cut and sealed foot of the sail will need trimming.
The sailcloth is specially supplied to my exact specification and size
It is oriented LDPE and I obtain it from JR Sainsburys is sail size billets - the sail template exactly gets two sails from one bag:p
Does anyone have any rule-of-thumb or a calculated ratio or a measure of the distance of the C. of E. of the McCormack sail ahead of the C.L.R. of the hull?
I have made two rigs and several sails, but each time I end up bending and re-bending the wire supporting the “fore-stay-mast”. So far I have not achieved real controllability or hands-off upwind performance. I note that some people indicate that the McRig points higher than conventional rigs with fore and main sails.
You can get a rough location for C. of E. by drawing lines from each corner of the sail to the mid-point of the opposite side. Where they cross is the center of the area of the sail. The actual C. of E will be slightly forward of this point.
One of the positive aspects of the McCormack rig is its adjustability. It may be frustrating to re-bend the mast to find its sweet spot but that beats drilling a lot of holes in your deck.
Theoretically the McCormack rig (being close to a lateen rig in shape) should not point higher than a bermudan rig. I think that the observed effect is more one of tuning and the forgiving nature of the McRig on these tender boats. Where the lateen type rig should be superior is offwind, and the spring action that dampens gusts helps on these points of sail as well by giving the skipper more time to react. The C. of E. also stays closer to the centerline of the hull with a balanced rig on the offwind legs, reducing the tendency to broach.
I’m pretty sure that the ability to point high comes from aerodynamic efficiency, and a high aspect rig wil always have lower tipo losses, and probably operate in faster, cleaner air.
All the MacRigs I have seen have been of the “cobby and cuddly” type with very low aspects.
Howsomever they hang a very good sail shape simply, and this, simplicity and lightness may be the deciding features
I speak from perfect ignorance of model sailing, but some of the perfection is getting diluted by helpful footyers and scale sailers
I only have one Footy at present and a set of 4 McCormack rigs of various sizes. They all seem to work reasonably well when the sail C of E is 48mm forward of the hull CLR. They will run hands off only in the right conditions - if a small gust hit it causing the hull to lean a bit more then it turns to wind very quickly.
The received wisdom with larger boats can suggest anything up to 20% of the hull length - so my Footy comes in at about 16%.
Finding the C of E and CLR is a different matter though. The sail geometric C of E can be found by joining the mid point of the sides to the opposite corners only if the sail is triangular. Anything else and you are best off making a cardboard pattern of the sail ( 750 gram Cornflake packets are nice and big ) If the cardboard isn’t big enough just join two pieces with CA. Then make pin holes at the main corners and hang the pattern from a convenient door edge. Drop a plumb line from the pin ( a piece of string with a small weight ) and mark the bottom end on the card. Repeat this for all three corners. Join the bottom mark to its respective pin hole for each position and, if you’re lucky all three lines will cross at a point - this is the geometric C of E.
The hull CLR can be found in the same way. Draw the underwater shape by using a set square to set up the hull on its side. Mark the Water Line at the bow and stern and then just use the set square to plot the hull shape onto a pice of card.
The purists would say thet both the sail C of E and the Hull CLR will change when the boat is underway. This is true, but both of these changes are almost impossible to define. Sticking with 15 to 20% of the hull length is a good starting point.
Hope this helps,
Litefoot took to the water last Saturday at a footy race meeting.
This was as successful as one could expect - considering I had left the sail servo at home.
Befoer setting out for Bournville I had also run into a snagette - not enough hull volume to fit batteries, rx and sail servo. Part of the problem is the bulkhead I have ahead of the fin which shuts off the entire bow.
I had planned to fit the cells as two 2ubes fitted either side of the keel but pressure of time led to me using a Lipo (2S) for the trial cruise and the lack of sail servo helped by putting the RX amidships
New MacRig, seemed to work in the bath:)
Sails by Sainsburys - cut with soldering iron
Keel bulb from sheet - two 55gm lead “teardrops” cut out, bent 90deg along the long axis, and epoxied to the fin - see pics
Weird idea, but gets the weight a little lower, acts as a stand (flat bottom!) and acts as a discussion point. “What are you on, andrew?” is the most frequent flattering comment
Anyway -trial sail, Went well - rig fixed at 10deg position using blutack on the sheet.
I was well pleased until totally uncommanded actions ocurred.
No worries - this turned out to be another sailer also on “green”, so I freesailed for 10 minutes or so, negotiated for a a short time on the frequency and regained the shore.
So success in a large degree - watch this space
I have now found the basic reason why sail control was ineffective at the Bournville meeting (great day, but not warm!)
Yesterday I found the sail control servo, mounted on its hatch in the drive where the car was parked as I loaded it.
Evidently the servo lead and sheet were not long enough to work over 60 miles:)
Anyway, now reunited with Litefoot I will have a controlled test sail next w/e and see how things work.
My first MacRig - designed by the old sailing principle of observation, vast use of mainframe computer using CFD, and straight copying of what works for someone else.
I also need to make up some 2-hi battery holders since they have to slip into the stern straddling the rudder servo. This leaves the Rx up front velcro’d onto the side of the fin.
I still havn’t discovered a good place for the aerial on footys. I like vertical aerials, but this isn’t so easy with carbon masts or Macrigs.
I know, buy a Specrum! operative word is buy, so this won’t happen
Results of trials to follow
Thank you, First Footy, I will persist, but my sailing water is starting to turn hard. Do you have an explanation for this unwelcome phenomenon? To be serious, I haven’t found any R.C.sailing boat that does well as an ice-breaker!
I will use your 48 mm. estimate as a starting point, but unfortunately, not until the spring.
Which suggests that the Bournville Regatta did happen… any news of the event Andrew?