Master Airscrew Balsa Stripper

16 December 2015

I could not cut balsa strips accurately.
I used the stripper in 3 manners.
The first manner was to hold the balsa sheet and feed the stripper through the sheet. I could get  the sheet edge to run along the stripper but not to get the sheet to consistently lie flat on the perpendicular arm of the stripper. It seems that doing it in the air is not good enough.
My second method was to extend the blade until it nearly touches the base of the stripper and then with the balsa sheet flat on a working surface, to run the stripper along the edge of the balsa sheet. With this manner, I noticed the blade wandered due to its flex.
My third method was to reduce the blade to slightly less than the thickness of the sheet. Then I raised the balsa sheet and ran the stripper through. This seems to work better but it was a chore and I have to break loose the strip.
In my opinion, these are all failed attempts.

After thinking it through, I think it should be used like this for better strips.

Procedure:

1. Set the blade normally, where the grooves are. The tip of the blade do not extend longer than the depth of the stripper.
2. Raise the sheet on the work surface. The top of the sheet should be less than the depth of the stripper. The packing surface should be set behind the edge by more than the intended width of strip.
3. Run the stripper against the edge of the sheet and with the stripper flat on the work surface. Ignore the perpendicular arm of the stripper. The blade should run clear of the packing edge and off the work surface. 

This way, I will be using the cutting edge of the blade and not the cutting tip of the blade, and this is thicker, less flex. While it doesn't gaurantee that the strips will be straight, at least the cross section would be consistent.

Other considerations:

1. Use hard balsa sheet for stripping; soft light balsa sheet are of no use for strips, if it gives slightly when pressed with finger pressure alone, it is definitely non-loadbearing. Don't waste time stripping soft light strips, I can afford the 'additional' weight.
2. Use 2 wood blocks (now where can I get them?) to hold the balsa sheet in position: one as the packing piece to lay the balsa sheet, the other over the balsa sheet. They should be longer than the length of balsa sheet in used. While the length of balsa sheet is 36" or 1000mm, I think I will use shorter lengths simply because they are cumbersome otherwise. So, just cut the sheet to shorter length because I don't need strips that long.
3. While the grain of balsa sheet comes running along the edges and won't pose a problem, it has to be checked. If it is off, a straight edge and NT cutter should be used to set the edge along the grain before stripping it down to strips.
4. The first strip can be thrown away if the sheet's edge has any nicks or is rounded. Just use the second strip from the stripper.
5. A bit of curvature in the strip should be ok because balsa is pliable anyway, so just use it where there's some bend in the frame. If it is too much, again use a straight edge and NT cutter to set the edge of the sheet.
6. Unless the framework is symmetrical and all strips are of the same hardness, the frame will pull out of true because of the build up of stress when bending strips.
7. It looks nicer when longerons are the same width and the curved portion bent from balsa strips, but it is ok to use wider straight longerons or sheet keel pieces.
8. Steam the framework while it is still pinned to the building board to relieve stress, I think this is often overlooked and it should be done to relieve stress as much as possible before it is removed from the building board.

WBP-1, EPB-1C

25 November 2015

Full size is 27' x 4' wing. Do one for slope soarer?

Use WLToys receiver with Flysky module for elevon mixing, only elevons with pushrods at bottom of wing, fixed rudder, full span elevons. Maybe to 1/12th scale with folded foam for fuselage and clear canopy (with a pilot inside)? Then receiver and battery can be hidden. And when I can't slope soar it, maybe I can do a pylon mount for a 7-8mm brushed motor direct drive spinning Hubsan type of propeller? Or how about twin 6-7mm motors out on the wings?

Airfoil for the wings would of course look good, but since this model is going to have a very light wing loading but used for slope soaring, the drag has to be reduced so I shall thin the wing down, that and the fact that 3mm foam wing with 3mm balsa leading edge and thin plate airfoil for the 27"x4" wing is easy to construct.
Canopy and top decking maybe moulded from clear PVC sheet, but that means I shall have to make a male mould and a plywood cutout.
The lower fuselage can either be made from 3mm foam. Alternateively, if I use PVC sheet, it is more durable afterall the fuselage is very short. The top nosepiece can be stretched PVC over a blue foam mold without the corresponding plywood cutout. The nosepiece is glued to the PVC sheet sides and bottom sealed with another piece. Perhaps I can use this lower fuselage like a removable pod for access to electronics and battery.

 

14 September 2014

Sub 40 gm.  Flies great after CG is appropriate.  Nimble and good glide. I was concerned about the large nose area.

Profile Scale
Span 20"
Chord 4"
2 gm brushless on 1s esc (1gm) 1s150mah, 3"x2" prop.
Throttle and elevons
Mass sub 40 gm (5gm noseweight)
Compressed foam sheets 5mm.
S-airfoil, carved leading and trailing edges with NT cutter.
1mm balsa fins.

Sopwith Pup, Sopwith Triplane

25 November 2015

Alternative to CF cabanes, struts and undercarriage is to use plastic sheet by cutting the plastic sheet (pvc clear?) to shape with glue tabs and then bend and glue to model. This seems more accurate, simpler and easier to do then CF rods and there are no need for blue foam blocks. If some parts need to be stronger (compression), then glue some CF rods to the inside of the plastic parts.

21 November 2015

Cowling can be made from blue foam. It can be halved so that the top half can be removed for battery access and replaced before flight. The top and bottom halves can have magnets to hold them together. The bottom half to have a slot to glue on the geared motor. The bottom half is glued to the fuselage.
Fuselage can be made from 3mm foam sheet to a U-channel, open at the bottom. Some formers are glued to the trough and some to the top and sides. The top decking can be a piece of paper glued to 3 top formers: behind the cowling, at the instrument panel and at the back of the cockpit. It should be rolled to a curve and has the cockpit cutout removed last. The rear turtle deck can be a piece of paper, bent to resemble the stringer lines, and glued to the former at the back of the cockpit and the former at the front of the horizontal stabilizer. The rear turtle deck should be glued before the front decking. The side cheeks an be 2 pieces of paper, scored to resemble the stringer lines, and glued to formers behind the cowling.


To have the servos exposed on the starboard sides is an attractive proposition. Another attractive proposition is to have the servos hidden in the fuselage trough with the pushrods running internally.


For ease of cabane set up, simple blue foam blocks can be glued at those locations where the struts will be anchored. The completed fuselage, i.e. painted, finished, controls in placed etc, can be drilled at the oblique angle for CF rods. The CF rods are passed through the top wing's centre section and into the drilled holes. When the top wing, painted, finished, etc, is at the correct position, CA will lock all in place.
A similar approach can be used to strengthen the fuselage at the bottom wing's position. A bit of blue foam to fit in the U-channel, thus making that section a box, and with 2 CF rods grooved in, the lower wings' inboard sections rest on the protruding CF rods. The wing struts are also CF rods and passes through both top and lower wings. When the lower wings are in the correct position, use jig if necessary, the CF rods are CA'd, at the wing struts and at the inboard sections of the lower wings. Add two more pieces of blue foam behind the cowling where the landing gear is and the undercarriage can be assembled similarly.
Obviously the exposed CF rods has to be then dressed up, either as cabane or wing struts, or as undercarriage. This can be simply folded pieces of printed/painted paper.


If I prepare the blanks for the foam sheet fuselage and paper coverings, it would be easy to make another fuselage and use that for a Sopwith Triplane model, which as I understand having read it somewhere, that the real Sopwith Triplane uses the Sopwith Pup's fuselage.

11 November 2015

Mount it this way?

5 November 2015

To improve the odds, I think it should have a lifting tail. When the CG can be moved back, the items in front of the CG will have a bigger moment arm and less noseweight is required.

My modelling experience started with chuck gliders. Wings and tails were mounted with zero incidence in order to have higher launch height. Otherwise the gliders would be looping and would transitioned to glide attitude around knee level! Those tails were from sheet balsa, the airfoil might have been lifting but I doubt I did that. My CG were mostly around the 25% mark except for tailless which was something like 10-15%.

Then I progressed to control line planes. Again the wings and tails were at zero incidence. CG was less important and level flight is achieved with the control line system.

I started RC with simple trainer planes. This time with some incidence in the wing and the thrustline had to be offset. But my RC planes/gliders had sheet tails or built up flat tails and this continued to present day because I didn't think of it and even if I did, I wouldn't have done a lifting tail from foam sheet.

My flying experience was incomplete because I did not do free flight models. And because my experience has always been with flat tails, I always considered that tails should no purpose apart from correcting the attitude, i.e. be set trailing without up or down force (like in aerobatic planes) or when I need more stability, provide downwards moment.

I think I should use a lifting tail for this model. On closer examination of the dimensions of the material indicated on the plan, it seems that was intended too.

I would probably still use foam sheet for the tail, and I would not sand any airfoil, but I would make sure that it shall be set at a positive angle to the thrust line, and set the elevators down slightly so it may be a cambered/cranked airfoil. This would of course mean that the wings should be set at an even higher positive angle. The aim of this combination would hopefully result in a model with a rearwards CG and therefore a lighter one, and the fuselage set head-on to the direction of flying, i.e. not the usual pitched up attitude.

I could do a simpler model that uses a 'lifting' tail before doing this Pup.

3 November 2015 (review of 6 July 2015 entry)

Won't be so lucky to find a suitable plastic bottle for cowling. They would be close but not exact. Also, with such a short nose, it might need noseweight but plastic is light although resilient. How about making a blue foam male mould and make a paper mache cowl?

How about making the fuselage and rear deck stringers in one piece? A rectangular piece cut out for servos will fit from the cockpit forwards. The front and side deckings (including stringered portion) can be paper/card. WLToys 8.5mm motor can be glued to a slotted (with side thrust) piee of balsa, and the balsa glued with slight downthrust. The WLToys receiver fits infront of the rear cabane, with the servos in an upright position. This would mean running the pushrods within the paper/card front decking, passing through the cockpit and pilot, under the rear stringered portion of the fuselage and exiting to the tail.

But it ought to be quite troublesome to do all that, maybe something simpler like letting in the receiver/servo block to the starboard side of the model? Like what was done on the Kirby Cadet? The starboard side decking may just be enough to cover/camouflage the exposed servo horns, and maybe the pushrod should just be left exposed, i.e., outside on the starboard side. Within the fuselage box, the port side should have enough space for the battery. I still think battery should be dropped in from below, this way a paper rotary engine can be glued on the propeller shaft. Maybe the battery could be slide in from the bottom, just behind the cowling, at an angle and retained by what-else but those velcro spots? Angle = weight forward and avoid cutting of lower wing.

The wings, tails and interplane struts seems ok, but I think the rear cabane struts should extend to anchor at the base of the fuselage, in the middle between the rear legs of the undercarriable. The front cabane struts would not be able to extend through because the motor would be in the way. For the anchor point of the rear cabane, rear legs of the undercarriage, might as well make it the support point of the lower wings.

Should the undercarriage be made removable or hinged so that the battery may be placed there? I would prefer a one piece lower wing. If I can bend wires precisely, maybe the front cabane should be tied to the front legs of the undercarriage.



I shall study some photos of the Sopwith Pup.

6 July 2015, Shall I?

The plan fits nicely on 2 pieces of A3 paper.

The fuselage may be built from a piece of plastic bottle for cowling, creased and lined paper for front and side decking including rear stringers, over a basic structure of 3mm laminated foam folded all the way to the front of the cowl.

Wings and tails are cut from 3mm laminated foam. Stick on  paper reinforcing rings to the underside of top wings and upperside of the bottom rings to spread the loading points of the interplane struts and cabane struts. Draw lines for the ribs and ailerons. Silver for riblines on the upper surface. Black for the undersides and aileron hinge lines (both upper and lower). Spray green khaki for upper surfaces and cream for lower surfaces. To the upper wing, cut two slits past the centre section, crease the upper wing and insert CF strips, when dihedral is correct, drop in some superglue and touch up.

Interplane struts are from 1/16" balsa, pre-painted brown before inserting through the pair of wings. Snipped off when the wings are at the correct position and touched up after installation.

The cabane struts from 1/16" CF rods, pierced from the top surface of the top wing, all the way to the fuselage. Snip off and touched up after installation. The struts shall be faired with pre-printed paper.

My instrument for measuring angles and deflection

4 June 2013

I spent $10 and bought this throw meter from SHS. It appeals to my 'sense of balance', but...

My ailerons are broad and made of EPP (3D plane). My HS65(?) servos wouldn't hold that amount of weight if unpowered and clipping on such a device off the trailing edge flexes my ailerons.

So here's what I did. It is easy, cheap, light and can be used in many ways. It can also be 'zeroed' if the surface is tapered.

Piper Pawnee

23 October 2015

PVC cover is used for the canopy. I cut the card canopy to use it as template. A bit off, but I shan't be bothered further.

A pilot is seated in the cockpit. The edges of the cockpit shall be painted black using marker pen.

I wanted blue clothes but don't have blue marker pen. Let's wait until the bust is dried before some detailing and colour washes.

20/4/2015 (Walt Mooney's Piper Pawnee)

Canopy

Mark dimensions on a card, cut, fold and glue together. Trim excess. Decorate to define the cage.

 This is only a trial. The cage should be white.

 Fuselage

Mark dimensions on a piece of paper, cut, crease, decorate, fold and glue together with foam formers. Trim excess.

 This is only a trial, the fuselage is wide enough, but do I have the right equipment?

Pilots for model planes

23 October 2015

The flying bronze man and underaged pilot are colour washed in yellow and brown.

 

More dough is used to make the bust and arm. Seated on a foam piece, it is drying before details are added.

 

 

 

 

 

 

 

 

 

 

 

 

5 October 2015

I did this with Paulinda Super Foam yesterday. About 15 minutes.

 

This is moulded on the other end of the plastic tube which has the pilot with head full of hair (so much that James called it underaged). I don't want to waste the effort of mixing 'flesh' colour paint nor the plastic tube.

 

This time I made it bigger. Thang said it is a flying monk, and James said it is one of the bronze man from Shaolin.

 

 

 

 

 

 

 

 

 

28 September 2015

On Saturday, I went to the nearby Popular Bookstore and bought some paints and pens and even chalk.

I start with the polystyrene pilot.

$2 for 2 sets of 12 colour pens (water colour) isn't bad at all.

 

Before long, it was painted. I used yellow and pink for the flesh tone. Brown for the flight cap and blue for the jacket.

 

 

 

 

 

 

 

A fine pen was used to draw the brows, lip and eyes.

 

 

 

 

 

 

 

 

 

The texture of the polystyrene shows and waterbased colour pens and the fine pen seems to have some interaction.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

But it would be alright when under a canopy.

 

 

 

 

 

 

 

 

 

 

 

Still weighing 0.0 gm.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

And by this time, the Paulinda Super Dough torso has lightened by 0.5gm. The weight is now 2.3gm. The torso seems to have shrunk.

 

I didn't want to bother myself with painting the torso. Which looks quite unreal anyway. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I tried making a spinner from Paulinda Super Dough.

 

 I made a conical mould and pressed the propeller shaft into the dough.

 When dried, the dough was peeled out and trimmed.

 

 

 

 

 

 

 

 

 

 

 

 

 

 0.3gm isn't bad.

 

 

 

 

 

 

 

 It won't run true. The end product while usable is considered failed.

 

 

 

 

 

 

 

 

 

 

I made another pilot last night. This time, I want it to be smaller than the polystyrene's but has better texture and lighter then the fimo/paulinda super dough's combination.

 

I added more hair then normal this time.

 

James think it is under aged.

I will see how it goes after it has hardened. This time I shall have to paint it. Maybe I can make the torso from tissue paper.

 

 

25 September 2015

Yesterday was Hari Raya Haji, the air quality was in the unhealthy range, so I stayed at home and made little pilots (head of less than 1 cm).

I mixed a bit of yellow and pink to get the peach colour of  skin (Regina thinks that 'colour of flesh' is too urgh!)

I didn't use the 'flesh-coloured' clay because 1) I am running out of it, 2) it pales when exposed to sunlight, 3) there should be a variation of 'flesh-tone'.

Yeah, this mix will also lighten with sunlight.

The peachy lump was moulded around a cotton bud. This is to save clay and provide a holder. Some depressions and it was done.

A bit of brown was rolled into a thin line sausage. Bits of this was added to become the pupils and eye-brows.


















Since I have the brown clay out, I made some squished round balls of it and applied it to the bald head.

I took some black, flatten the a thin sausage of it and applied it to the hair before adding two small flattened balls for the radio/ear muffs.

I baked it for 30 minutes and weighed it. It was a bit heavy at 1.6 gm.













I used some Paulinda Super Dough for the bust. I test fitted it and weighed it again. It was heavy at 2.8gm before the dough was dried and it was too big.

The Super Dough seems to have puffed up. To be expected, otherwise it won't be as smooth.










 I want a smaller and lighter pilot and chopped one up from expaned polystyrene foam.

It weighed 0.0 gm before painting.

How shall I paint it? White glue first before the 'flesh-tone' acrylic paint?

 

 

Pilot for the Kirby Cadet

I did this on 12 Sep 2015.

 

A short section of drinking straw was wrapped in polymer; first the flesh coloured, then the hood/coat because I have so little of the flesh coloured polymer left.

 

After baking at 110 degrees celsius for 30 minutes, I dotted the eyes and drew the eyebrows with a fine pen. Then I cut the goggles from a pvc sheet, and using the edge of a silver marking pen, painted the frame of the goggles. Not shown here is the short length of brown thread to simulate the goggle strap. It weighed 2.4gm.

 

 (FUTURE) Farman Sportster Postale Carte 

I did these on 16 Feb 2015. I want to make a RC Farman Sportster Postale Carte running on 1s cell, GPS-8mm gear motor. It's a two seater and I need two pilots, 1" tall as measured from the plan.

 

 I started with blue foam because I don't want to use too much polymer clay. It's not the cost, but the ease of availability. I'd have to order some more from Banggood, but what I am really interested is the skin tone polymer clay. From these bases, I chose two and started with the face and then the rest of the head and finally the clothes.

The one at the back was my 1st attempt. It was done in about 30-60 minutes. Then, on my second attempt, my fingers grew tired and I was less focused, making a mess.

I searched the internet for information to see if the polymer clay might air-dry in a week and discovered that I have to either boil it or bake it at 120-150 degrees celsius.

 

Since it is necessary to bake, the next thing I wondered was what would happen to the blue foam. I discovered from the internet that blue foam (XPS, extruded polystyrene) will reach it's 'glass transition phase' at 100 degrees celsius where it will be damaged. What this actually means, I did not know. I was hoping that it means it can be molded like heated plastic sheet into compound curve.

 

 
This time, I baked them on a piece of facial tissue (last time I used aluminium foil). I don't think that tissue paper will burn at that temperature, so I tried this experiment to confirm it. The tissue wasn't even charred, but at the 8 minute mark or thereabout, a bubble was seen on the cap of the 1st model and the blue foam seems to be pushing out from the bottom of both pilots. I continued and these were the result.

Instead of trimming the foam pieces nicely so they may provide a gluing surface, I found the foam pieces were deformed and became much harder than before. So I simply snapped the chest foam pieces out. The head foam pieces are still lodged in the head. For the torn polymer clay, I superglue the edges together. The polymer skin is not brittle, some flex is ok, but obviously not like rubber or silicone.

Here's the underside of pilot 1. A thin shell of polymer clay with some shiny blue foam 'fused' to polymer clay. This is an accidental discovery of making thin shell pieces with 'automatic' male form removal. I didn't weigh them yet but they appear to be light. They are much lighter than the one I did for the Blackburn Monoplane. I won't bother to trim the bust, figuring that it won't be necessary when I will use hot glue or UHU Por to spot glue them at a few spots on to the plane (future).

 

I like polymer clay because they are pre-coloured, they have good smooth surfaces (not 'hairy' or pitted) and I won't have to bring out my painting utensils and bottles of paint.

 

Super-Dough? Still to develop a use for them.

 

Blackburn Monoplane

"Be there soon."

Action pilot made from oven baked clay (www.banggood.com) in flight suit from Super Dough (Art Friend).

Right hand on steering wheel while talking on smartphone. Rolex Blue Oyster on wrist.

 

Every Plane Deserves a Pilot (or two)

I started with a ball of fimo clay of the approximate colour and rolled it to shape of a head.
I used the spoon end of the brass ear pick to make depressions in the head.
The ears were made by flattening smaller balls in the shape of tear drops.
Then it was sent to my toaster oven for hardening.



The hair were made from a mix of brown and black filmo clay. I mixed it roughly, flatten it, and apply them bit by bit to the bald head. More clay was added to give the hair volume, and that was the opportunity to correct the shape of the head.
A sharp spatula was useful to flatten and apply the bits. I pressed the sharp edge of the spatula into the hair to make some linear expression and parting of the hair.

The eye brows were similarly applyed. The eyes were very small bits of clay applied with the tip of a needle. The lips were from vermillion coloured clay. I fabricated the hands and lower forearms from the clay. I made the iPhone 6 from clear plastic and magazine cutout and curl a hand around it. The fingers were seperated with the sharp edge of the spatula. The phone carrying hand also has a Rolex Blue Oyster at the wrist. The right hand was curled so that it may hold on to the steering wheel.

I made a mistake at this stage. Polylindah super foam (or something) was lighter than the Fimo clay, so I made the torso with it, and joined it to the head and the two hands. I thought it would be hardened by oven but I was mistaken. The super foam oozes out at a side so I ended up with slightly smaller torso after some emergency operation.

I was watching a Korean tv programme, that might explain something.

Scrapping with a needle's point can remove excess clay. I removed a bit too much and had to rectify that with a permanent marker.

Apart from the application of a permanent marker, no painting was required, so no mess to clear up.

Not bad for a first try.

Gee Bee Sportster

My steps in carving a pilot bust from blue foam

1. size up a rectangular block, straight cuts with NT cutter, sawing motion
2. draw the frontal silhouette on the back of block
3. draw the side silhouette on one side of the block
4. rough cut the side silhouette, first vertically and horizontally, then at those angled lines
5. rough cut the frontal silhouette, similar technique
6. chamfer the cuts to the head, neck, shoulders and chest/arms, to reduce sanding later
7. rough sand, deploy a mini sanding drum on small electric screwdriver/drill

The face of the bust is the focal of attention, to shape the blob of head into a recognisable face:

1. approximately half way down from the top, a horizontal V cut, this is the eye level
2. a nose is an inverted V with a straight cut connecting the V
3. cut away the area below the eye level V and the inverted V nose
4. cut away the mouth and chin portion from the bottom of the inverted V nose
5. sand
6. press with tip of blade to round the head or to deepen the impression of the eye/cheek areas 

It is possible to carve from anything that, well, you can carve! Blue foam is very light, easy to cut (not really carving), sand and paint.

Carving is a subtractive method. I suppose a bit of addition method might be good too, if I have the materials at hand. I am thinking of those light yet flexible polymer clay that comes precoloured. It ought to be easier and faster. A few colours of those clay mixed in the right proportion seems less messy than painting.

 

 

Pou du Ceil