Sprite
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- RNinMunichBronze
- Mike StoneyBronze
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- EdWBronze
Sprite
With both sets of stringers fitted to the hull, I thought I would start to shape the keel and doublers ready to accept the bottom skins.
After scraping away at the 18mm combined thickness of the full length keel and doublers with my various Permagrit tools, I decided to get the plane out and use that instead.
Progress was much faster and more easily controlled, but the finish was rather too nice and smooth (almost glazed) so I will "rough it up" a bit to allow the Jet Set PVA to penetrate the wood surface more easily before adding any skins.
With a nicely sharpened blade slicing through the wood, I lost concentration for a millisecond and trapped the pad of my thump between the edge of a bulkhead and the approaching plane.
The results were not too pretty and the blood stained some of the wood.
After quickly wrapping some masking tape over the wound to stop the bleeding I sponged the wood with cold water as quickly as possible to clean it as well as I could.
Now with the thumb more professionally covered with a plaster, I will venture back into the workshop (shed) to see how successful I was at cleaning the wood and as soon as it is dry enough (!) I will rough-up the smoothly planed surface ready for the bottom skins to be glued on.
If the wood is still a bit damp, I will start to make some templates for the bottom skins using some old cereal packets taped together to make them long enough.
Bob.
Sprite
It looks like the sort of boat that would have an outboard on in real life.
Will
Precedent Fairey Huntsman 46"
Veron Fairey Huntsman 28 42"
Precedent Fairey Huntsman 36"
Aerokits Sea Commander 34"
Aerokits Sea Rover 29 1/2"
SLEC Fairey Huntress 23"
Sprite
......in-fact I think it probably looks better with the outboard motor on it than it does without it....
Beauty is in the eye of the beholder, but with or without an outboard motor, I think this could be quite a good fun boat and the blunt nose will makes its secondary use as a recovery boat very helpful too.
The 30" size should also make it a lot more useable for 12 months of the year too.
Bob.
Sprite
Sprite
This is going to be one chunky boat!
Bob.
Sprite
It looks a large model sat there on the bench 😎👌
Can't wait to see it on the water, I'm sure it's going to have real presence.
Precedent Fairey Huntsman 46"
Veron Fairey Huntsman 28 42"
Precedent Fairey Huntsman 36"
Aerokits Sea Commander 34"
Aerokits Sea Rover 29 1/2"
SLEC Fairey Huntress 23"
Sprite
Lots of clamps were used and a brass tack was partly driven into each bulkhead position to firmly laminate the two layers together with a good coating of Perkins Rapids Grip PVA.
Once this glue is fully dried I will remove the clamps and brass tacks and reuse them all on the next outer stringer that I will fit on the other side.
Bob.
Sprite
The lines look good and flow OK so I am happy that everything is square and aligned correctly .
The elastic bands were handy when placing the stringers onto the frames, but a sharp brass tack is driven into each bulkhead to hold them in place until the glue dries.
When dry, the tacks and the elastic bands will be removed.
The small vice is loose (not bolted down) but is heavy enough to hold the frame when needed.
Bob.
Sprite
Any lumps or bumps will show easily, but we are hoping to see nice smoothly flowing lines for both.
This will also be the first time that we can see the shape of the hull described in wood with a frame being prepared for skinning. For me, this is always one of the best parts of any new build.
I will fit the first (inner) pair of deck edge stringers tonight and hopefully also be able to fit the first (inner) pair of lower gunwhale stringers too.
Bob.
Sprite
Funnily enough I did initially extend the cabin sides to Frame 2 but decided that it wasn't really doing anything so stopped them at Frame 3! As far as the angled cockpit/cabin side goes, I was going to do it in two pieces and fill the joint if needed with P38. That way I can adjust the lengths easily if required.
Sprite
Here are a couple of pictures of the frames assembled onto the keel.
This prototype will be built to your original "straight sided" cabin plans.
The long steel ruler was used to check that the cabin sides were straight (first picture) as the slots for the cabin sides are slightly too wide due to the reduced thickness of them - after I had widened the slots to take 4mm cabin sides.
Your later drawings will show the cabin sides following the edge of the hull with perhaps a shallow cut into the internal cabin sides at the peak of the direction change (as per LesRo Rapier construction) to help the cabin sides comply with the direction change?
Once happy with the alignment of the prototype, I used a small dab of super-glue to tac some strategic points together (shown here) so that I can measure and check everything more carefully than I could with everything loose.
Although the gap between Former 2 and Former 3 will have a 1/8" x 1/4" strip on each side to join them, I think I will beef this area up a bit due to one of its intended uses as a pusher tug.
If I build another Sprite Plus I would extend the cabin sides to join onto Former 2. Other than that I think the design works well enough.
I have checked all the bulkheads against the keel with an engineers square and everything aligns OK.
Bob.
Sprite
I do have obeche but I only use it for motor and servo mounts. It is a nice timber but I would have thought it is too stiff for stringers and the like? I use bass mostly for my strip wood as it bends and sands easily, along with mahogany for when it is varnished.
Actually thinking about it, I think it is beech I use for engine mounts etc. which is very stiff. I don't think I have used obeche. I'll get some on my next order and try some. If it is similar to bass/lime I don't think you will find anything better for general timber than bass or obeche.
Will be interesting once you start assembly.
Sprite
Some more 1/8" x 1/4" strip (3.2mm x 6.5mm in metric) needs to be ordered as my stocks are running low.
I usually allow 20 of these strips per new build to cover all the stringers, deck edging etc.....and hopefully leave a couple of spares for repairs and future projects.
Traditionally , I have always bought obechie strips for this - probably because that was always the type of wood that was always included in my early Aerokits kits, but I do see more choices available these days and wonder of anyone has any thoughts to offer?
Chris has specified bass wood for use as the stringers on his plan for the Sprite Plus so I would appreciate any helpful inputs from anyone who can advise the different "qualities" of each type of wood as maybe obechie is no longer the best option?
Bob.
Sprite
The Hegnar jigsaw was dusted off last night and used to cut out the cabin windows and the centre void of Frame 3, so I can start to look at assembling the bulkheads and cabin sides next after I have cleaned them up.
I saved up any spare cash that I could find for many years to buy my orange coloured Hegnar Jigsaw. I remember seeing the adverts for them when I was still at school, and so it was a schoolboy dream to own one after years of cutting out my model aircraft parts with Xacto craft knives !
The Hegnar Jigsaw cuts surgically accurately and has very (very) fine thin blades, but it is a slow process compared to the bandsaw and I have yet to fully master the timing to prepare and move the wood quickly enough to always stay on the line when cutting a tight curve!
I had a basic jigsaw before this Hegnar and the blades on it were much wider and a lot easier to guide and keep on the cut line. I suppose it's a bit like comparing driving my regular car with an F1 car - one is very user friendly and the other is really sensitive?
I really must make the time to practice using the Hegnar jigsaw as it is clearly a very good machine that has great potential and cuts very cleanly ....but for now, and with some minor adjustments with a fine file the cut-outs look OK...🙄
Bob.
Sprite
Nothibg wrong with "Bodging" think you are right past masters have always worked with what they have and let their skills fill the gap. This much undervalued skill I think is one of the biggest problems with people today.
Regards
Adam
Proud to be called. "bodger" 👍👍
Sprite
As a matter of interest, I thought I would just check to see if I had any imperial weight sizes of birch plywood left from the 1960's.....and I don't.
I checked again the size of this sheet of wood that I used to cut the Sprite Plus cabin sides from, and it is 3.5mm thick.
The other sheets that were stacked on top of it and underneath it are 4.0mm, and were probably bought from the same supplier, and at the same time as this one.
I also checked the conversion from 3.5mm to imperial fractions of an inch and it is 9/64".... an unlikely size for a plywood sheet seller to stock, so I think I was just unlucky and this particular sheet of 4mm birch plywood was a little under-weight.
.
There must be a reasonable tolerance for the plywood manufacturer to have and 0.5mm is only around 1/64". so I think I will just get on and use the cabin sides that I have cut from it and make any minor adjustments that are needed to the fit as I go.
Some of the most skilled wood "craftsmen" from many years ago were called 'Bodgers" and they would work with whatever materials they had to hand (seldom with uniform sizes of wood) to produce something serviceable, and so in the best tradition of a Bodger, I will work with this slightly under-sized plywood and hope that I don't "Bodge it up" .......in the more recent meaning of this classic term...........🤓
Bob.
Sprite
A pair of cabin sides was drawn and cut out on the bandsaw last night, but when I checked the interlock fit I found that the slots that I had just enlarged were a looser fit than they should be.
I stack my plywood sheets in 12" x 48" lengths (some in 12" x 36" lengths) on shelves that I made for the purpose years ago to keep them stored flat and warp free, and I have a separate shelves for 3mm, 4mm and plywood skins with heaver weight wood underneath and on top of them to help keep them nice and flat.
My stock has been dwindling over the years and I am overdue for a new wood purchase, but I have not had any 3mm plywood for some time, but I do have some sheets of 4mm left.
The "4mm" sheet that I had pulled off of the shelf was under-weight! It actually measured 3.5mm - a size that I didn't know existed!
I was a bit annoyed with myself for not checking this before I cut it, but I keep all of my 4mm wood on one shelf that only has this size stacked on it....but I will double check next time!
My few remaining sheets of 4mm do actually measure 4mm so I was unlucky when I chose` this one. I am not sure about dumping these cabin sides and cutting a new pair - or just carry on and work with what I have.
I will go out and take anther look at it later and decide what to do. Packing the slots to make a tight fit is not really a problem (and invisible when the boat is finished) - just a bit annoying!
Bob.
Sprite
The slots (and cut-outs) to fit the 3mm cabin sides are being opened-out to accept 4mm cabin sides.
........if I realised that I had no 3mm ply for this job, I would have drawn them wider before I cut the formers out!
Not to worry, all the bulkheads fitted tightly into the keel between the doublers (no slop) and look aligned OK when checked with an engineers square......but we all know that means "didly sqaut" until the cabin sides are fitted into place to complete the interlock!
I opened up the prop-shaft slot with a rough-cut round file. It has a very rough cut that I believe is called a "bastard cut" (genuine terminology). I only needed to rock it left and right as I pushed it into the keel slot and it cut it away quite easily......wish I had one years ago !!!!
This round file also left a really nice rough ridged internal finish when used this way - perfect for the 24 hour Araldite to bond into and hold the new propeller shaft securely👍
Just going out to the workshop (shed) now to make sure I really do have some 4mm plywood long enough to cut the cabin sides out of................
Bob.
Sprite
Everything is looking OK so far.
The top line of the cabin side could have a slight change in the rake if it peaks at the top of Former 5, but it looks OK as it is, so I may choose to leave it.
All of the bulkheads were cut out on the bandsaw last night, it took about an hour with more time being spent working out the best entry and exit routes for the saw blade that actually cutting the wood!
I have not cut the middle out of Frame 3 on my fretsaw yet, but I did (briefly) consider slicing it along the datum line so that it could be more easily cut out in two halves (top and bottom) on the bandsaw (or by hand) with anyone who did not have a fret saw.
This option would be glued back together again afterwards with a small ply skin support plate bonded onto the front facing side (each side) where it would probably not be seen in any case as it would be hidden in the void.
Bob.
Sprite
Sprite
Frame 5 and the rear cabin wall drawings have been combined as this Sprite Plus is being built with an integrated cabin and not a variant with lift-off superstructure so it does not need a separate cabin wall.
Frame 6 has been modified since this picture was taken as it needs to straddle the combined thickness of the 6mm keel and the two 6mm doublers as I incorrectly failed to notice this when I was cutting the templates.
This gives a total of 8 bulkheads (including the transom). All bulkheads will be cut from 4mm birch plywood.
Bob.
Sprite
Making the bulkhead templates and transferring them onto 4mm birch plywood comes next.
Bob.
Sprite
Sprite
I have been using-up my supply of old glues and the JP aliphatic still works OK, but it really does leave quite a dirty yellow stain.
Although I used to use this glue quite a lot in the past, I don't remember it being quite this dark a colour, but I don't have much left before I start on the next opened bottle of PVA that I used when building my Kopy Kommander.
Luckily the areas that I am using this glue in will either be hidden or out of sight when the boat is finished.
As you can see, I have not cut-out the bulkhead (Frame 2) as it is so close to the blunt nose ( Frame 1) and given one of the boats intended uses (recovery) I may even add a couple of additional braces in this area between these two Frames to further reinforce the blunt nose as it will become the mount for the "pusher plate" when I get around to adding one at a later date.
One of the two 4mm brace's that I cut to fit on either side of the 4mm flat bow former can be seen in the bottom left of the picture. These will be fitted next before I make the templates for all the other bulkheads (Frames) and transom.
These are a lot of bulkheads (Frames) in this fairly short 30" long boat (8 including the transom), so this is going to be one very strong and twist free little boat.
Bob.
Sprite
Also it gives plenty of gluing area for the hull skins. Because of the low height of the keel it doesn't add much weight and it is low down anyway which is good. Sanding the total of 18mm is hard work though and gives my PermaGrit blocks a hard time which is why I had to buy another!
Sprite
The second pictures shows the "cut lines" that I added to the plywood that I used when I cut them out on my bandsaw.
All the 6mm doublers are now cut and fitted to the keel.
Bob.
Sprite
I will add the "cut lines" that I will be using to get the best access for the bandsaw and get them cut out and fitted onto the keel.
When I was sorting-out some scrap ply and soft wood off-cuts to make the basic stand for the Sportsman, I have put some aside ready to make one for the Sprite Plus so that it will be ready to use once I get the bottom skins fitted.
........but the next job will be to make the templates for the bulkheads and then find some 4mm birch ply to cut them from.
Bob.
Sprite
You drew the plans for this Sprite Plus with a 6mm keel.
I think I may cut all the doublers from 6mm ply as well - including those at the front of the boat to make sure that this is one tough chunky little boat that can be used as a pusher tug when needed with no doubts about its strength.
After I cut the keel, I sliced out the prop shaft slot and carefully assembled the 6mm doublers around it, making sure that the keel at that point remanned nice and flat.
The idea worked a treat, so I sliced the keel again further back to open the slot for the rudder and repeated securing the two sections of the keel between the rearmost 6mm doublers leaving the opening clear for the rudder housing.
If I make another Sprite Plus, I would not cut the keel out in one piece again, I would cut it in the three sections I have just mentioned.
It would save a lot of wood, and be much easier to cut out on a bandsaw.
As a matter of interest - the keel on the Sea Commander is only 4mm,,,,,,
Bob.
Sprite
Didn't want to go too mad with e.g. having curved cabin sides etc. as I think it is nice to keep largely to the original design and to keep the build simple and so that folks can recognise the heritage (even though the Sprite is quite rare) rather than it being a completely new model. Using angles does that.
I don't know why I separated Bulkhead 5 and the cabin wall - well I do, I was thinking about my usual lift-off superstructure! Of course now I'm using a fixed superstructure again so it will be in one piece like yours.
Sprite
I had already decided to make a “change of direction” in the cabin sides to follow the line of the deck edge at bulkhead 5 and will modify bulkheads 6,7 and 8 accordingly to fit.
A partial saw cut in the cabin sides at this point (ala Rapier) will help to give a positive direction change.
Bulkhead 5 will also be extended to the cabin top and replace the false rear cabin wall that would be needed for a “lift-off” superstructure.
My build will have a fully integrated construction with only the cabin roof and the rear deck well being removable for access.
I will add a curvature to the top of bulkhead 5 to align with the roof formers that I will add to the cabin roof base to give a nice shape to the lift-out cabin roof plug.
At the same time I may add a little rake to the front of the cabin sides before making the two halves of the front cabin windows to fit.
This is going to be quite a “chunky” little model.
I may make bulkhead 1 even thicker and sink a pair of M5 captive inserts into it so I can screw on an optional “pusher platform” to alternate with the standard blunt front, but I will decide this “at the time”.
Your drawings has certainly given us some things to think about and may well spawn several different “off-spring” variants.
Bob.
Sprite
Sprite
With me just mentioning the parallel sides I was working on the frames and the cabin/cockpit sides started to grate on me. 😮
So, I've angled them, just a bit to follow the shape of the deck edge, but still straight pieces to keep things simple to echo the original design. Similar to the Stiletto/Rapier project. Now I've thought about it there's no going back! 😁
I'll draw it up a bit more and you can see what you think.
Sprite
But it will be easy enough to add that in as an extra frame in your build method or even use my spacing and alter the frames accordingly. Because of the parallel design of the superstructure the only thing that changes is the beam so it's not a biggie and I'm about to do it again now for my frames to suit my fixed superstructure, albeit it off a flat deck.
Sprite
I realise that it will have no rudder stand or prop shaft slot, but is it otherwise the same?
Bob.
Sprite
In the meantime I will finish the drawings except for finalising the dimensions at the stern.
Suits me really as whilst I'm tempted to start building I can continue with my Faun and other builds.
Sprite
What I'm going to do is build the stern first and separately so that I can iron out any problems and if I have to rebuild it that's no problem. It can then be fitted to the remainder of the hull.
I'm sticking with building off a flat deck but have now decided to go back to a fixed superstructure which means I've got to alter the frames again!
Sprite
I did forget the flippin-floppin prop though! A prop up to 48mm dia. can be accommodated but I'm going for a 36mm initially. That means I don't have to drop the outboard too low in the water, though the props are semi-submersible. The bracket means I can adjust height for the best performance.
I don't know about you guys but I tend to do my best thinking when I wake up and before I get up or maybe having a shave! Used to do that when working and still do with my model boat builds and drawings. Many a problem solved that way that wasn't the day before or staring at a drawing.
Been that way with the Sprite and only this morning I was thinking of modifications to the stern and for fitting the outboard.
Sprite
I am hoping to get a copy of the modified drawings for the outboard motor powered variant from Chris, as I think it looks by far the best.
Making a second version will be much easier and faster that the first one will be !
Bob.
Sprite
Bob, sounds like you're making good progress on your Sprite build.
It will be great to see them on the water (mine too, eventually), as the Sprite is such an uncommonly seen model.
Will
Precedent Fairey Huntsman 46"
Veron Fairey Huntsman 28 42"
Precedent Fairey Huntsman 36"
Aerokits Sea Commander 34"
Aerokits Sea Rover 29 1/2"
SLEC Fairey Huntress 23"
Sprite
This will certainly ensure that the rudder is mounted completely upright as well as protecting the rudder post.
Cutting the keel (and rear doublers) out on my bandsaw did waste a little wood as it cannot turn as quickly as a fret-saw to include the rudder post support shape, but I really like the idea and I am pleased to have it on my Sprite Plus.
Bob.
Sprite
When I am home next I will cut the front 4 pairs of front doublers to complete the keel assembly.
The keel is cut from 6mm plywood, my Sea Commander keel is only cut from 4mm plywood - this is going to be one tough chunky boat!
Bob.
Sprite
I didn't realise this when doing the drawings but will certainly take that into account when building the Sprite Plus. Windows are better made by trial and error anyway, even the ones on my Faireys which were flat.
Sprite
I will check the "V" shaped front cabin window as I build because (as you suggest) things do get changed during the build if they can be "improved".
The design is coming alive with a mind of its own..........
Bob.
Sprite
I've made good progress on the drawings and it's not too far away from being ready to build.
I've decided to go with a lift-off superstructure which can always be held in place with fixings or magnets, though it would be easy enough to modify to your preferred construction. I'm also using a flat deck to build off and can add camber to the deck afterwards.
The motor is really designed for race boats and tunnel hulls and being quite short in height it's going to sit low in the water. This had me scratching my head but I'm there with a design now. In fact I've gone as far as I can now using pictures and diagrams with dimensions and so I'm just about to order a motor so I can finalise the design. Well until I start building of course when I'm bound to change things as I go along!
One thing you might be interested in. With adding a vee window I thought that the bow didn't sit right with it - I think you mentioned this earlier? Especially with the model being bigger now I think the straight bow is a bit much, it's Okish with a flat window.
So I've drawn a partly pointed bow at the same angle as the window. It takes away some of the pushability (made up word! 😊) without an add on but as it's going to be used mainly for fun that's what I'm going to do. The bow former/frame is the same it's just a bigger piece of balsa required to shape from!
Chris
Sprite
It's not until I actually cut the cabin templates out that I could see that this is going to be a really "chunky" looking boat - ideal for its intended duel purpose of occasional recovery .....and more often fun running!
It also looks like being a really good candidate for that large outboard motor that you have in mind, so let me know when you have made the changes at the stern to mount it as I think it could be a winner!
Bob.
Sprite
A mysterious tube was found in my chosen 'safe place" when I got home today - a pleasant find after spending some time in the dentist chair!
Inside the tube was some very professional drawings from Chris for the Sprite Plus.
Tonight I was able to take a couple of old Oatabix boxes (from my stash of old cereal boxes) and once flattened and joined together (where needed) with masking tape I was able to make some templates for the keel, the doublers and the cabin sides.
The keel has already been drawn onto some 6mm birch plywood and I am hoping to have enough time before going way again to make at least some of the bulkhead templates.
Many thanks Chris, I am really looking forward to cutting some wood for this model 👍
Bob.
Sprite
…..you could quickly knock-up a Remora in between all your other lengthy scheduled projects and have a lot of fun driving it while you wait for the Faireys to come out to play…..😂
Bob.
Sprite
I want to make a start on my water-jet project and then the Sprite Plus but I think they will be a few weeks away yet? I'm on the verge of ordering the outboard motor though.
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