Foamy Tucano Version 2 build thread

[freeman]

Hi,

You need someone to help you when you are cutting form core. It is very difficult to cut it all by yourself. You need 2 apirs of hands. Both end of the hot wire have to move at the same rate and the temp of the hot wire have to monitor too. It seems from your pictures that the wire is a bit too hot. Try to control your temp. Remember, Don't force it. You are melting not cutting, so let it go at its own speed. Also seems that there are some slack in your hot wire...
Safety note, if possible, connect your hot wire to your power supply that power your charger. The power supply will provide either 6V or 9V, which is more than enough to heat up the wire. Having live wire and un-protected transformer around your work bench is quite dangerous...

Happy building. It is always great to be able to build planes.

Cheers.

[P4cm4n2000]

wah Weeliano,

is this the blue hard foam from Artfriend ?
what's the weight of the wing ah?

[weeliano]

Hi Freeman,

I usually have someone to help me when I cut bluefoam or even styrofoam, but I have successfully cut wings by myself before. In fact, my old Tucano wings are cut successfully the first time without any flaws. I guess this time it failed because I'm trying a new method to cut foam wings, I'm not used to pulling the hot wire fast on one side and slow on the other as the foam block and templates are not of the same length on each end. I'll use the method which I always use but this time I'll use weights to hold the foam down. Actually I feel the temperature is fine, any cooler, the cutting speed will be even slower, the hot wire will cool down half way during the cut and I really have to concentrate on the pulling speed to cut evenly. The old method I use will involve using similar length templates and cutting on an equal length rectangular block. This way I can regulate my cutting speed evenly, I'll post pictures to show you what I mean.

I'm also not using Nichrome wire to do my foam cutting, I even built another cutting rig using Nichrome wire, but the resistance is too high and my transformer couldn't make the wire hot enough, so I returned to using Piano wire which is made of steel. The voltage that comes out from my step down transformer is 12 volts, it looks crude but so far I haven't caused any power trips at home yet and I don't leave it on for long stretches, I immediately switch it off after I finish cutting and wiping the wire free of melted blue foam.

I'm very sure I'll be successful the 2nd time round thanks for your suggestions though!


Hi Pacman!

Yup, the foam is purchased from Art Friend, you can see the yellow Art Friend Plastic bag in the photo displaying the raw materials in the first photo update.

Hi,

You need someone to help you when you are cutting form core. It is very difficult to cut it all by yourself. You need 2 apirs of hands. Both end of the hot wire have to move at the same rate and the temp of the hot wire have to monitor too. It seems from your pictures that the wire is a bit too hot. Try to control your temp. Remember, Don't force it. You are melting not cutting, so let it go at its own speed. Also seems that there are some slack in your hot wire...
Safety note, if possible, connect your hot wire to your power supply that power your charger. The power supply will provide either 6V or 9V, which is more than enough to heat up the wire. Having live wire and un-protected transformer around your work bench is quite dangerous...

Happy building. It is always great to be able to build planes.

Cheers.

[joe yap]

That's the exact disaster I'd encountered previously using piano wire. The heat is too high. I revert back to nichrome wire but with very slow cut since.

[weeliano]

Hi Joe!

Maybe you can tell me your foam wire cutting rig setup. What's the power supply settings you are using and where you got your nichrome wire and what is the level of resistance your wire has? Because the nichrome wire I have now although it's very thin, 0.4mm but it's resistance is so high that even at maximum power settings, it can barely cut the bluefoam, I'm sure it can cut styrofoam but I tested the wire on bluefoam it you need for force the wire through before it even go a millimeter!.

Cheers!
Still making the new templates...

[Tony]

I've had a some friends who purchased a foam wing cutting system and found it to work very well. It can even cut foam wings down to a feather edge at the trailing edge. I cannot recall the name off hand and will go dig up my modelling magazines for it. Has a name that sounds like Featherite or Featherlite something like that? It uses weights and pulleys to pull the nichrome wire. I've seen the output from this machine and its produces very smooth, ridge free foam wings.

Since you are a foam freak (I'm a balsa basher), this machine would earn its keep for you in no time. I'll let you have the details once I find it.

Tony

[joe yap]

I didn't have the specs for the wire, but should be quite the same you are using. I'm using 12V transformer for supply. With my setup, I can only cut up to 12" of blue foam properly. Beyond that, I've to cut longer wings in smaller sections or using higher voltage.

You should realise, from the pictures, the wing tip area has shrunken way too much. This is because your wire is too hot for the cutting speed at the tips. This results in excessive heat which causes the wire to eat up too much foam.

Perhaps, there are some people out there who has tried other setup with better results. As for now, my setup is sufficient for my needs.

[weeliano]

Update 5

Tucano Build Thread update 5

After the failure of last night’s foam cutting attempt, I decided to use my old tried and tested method of cutting same length templates. This time using Birch Plywood which is more heat resistant compared to balsa. The reason I don’t like using plywood before is that it is much harder to shape, but surprisingly, I found that with a very sharp blade and sanding blocks I can get the templates to the shape I want rather quickly. In the picture you will see that the newly printed templates are pasted onto the 2mm plywood.



Using a freshly broken point from the olfa blade, the templates are easily cut out and a little bit of sanding to get them smooth, this is important as a rough template will result in an uneven surface during the foam cut.


Holes are drilled with a modeling hand drill to enable the templates to be attached to the foam blocks with pins.


New foam cutting setup using same length foam blocks instead of tapered blocks.


Okay just want to show you guys this new cutting rig I built but in the end didn’t use because the nichrome wire’s resistance is too high.


Close up of the hot wire cutting rig.



Yeah success!! At last!


I was almost running out of foam at this point, no more margin for mistakes. I had to cut at an estimated speed of 5mm per second really concentrating to pull at a constant velocity. The extra piece of foam propping up the foam block being cut is extremely helpful. The weights worked fantastic! Now I don’t need anyone to help me hold the foam while I cut.




Now comes the messy part. This is what I prepared for sanding the newly cut foam wings. The fan is great for blowing away the toxic blue foam dust and the dust mask is an extra precaution. After cutting the tapered sections off, the wings still need a lot of work to get them aerodynamically correct.




I made 2 more sanding blocks with different grain sizes to help me sand easily. Blue foam is much more easier to sand compared to balsa, which means it takes nicks and dents easily too, so I have to sand with extreme care, not to over sand otherwise changing the shape. So I keep checking the wings while sanding to get them straight.




Using a Digital Scale, I made sure the wings are equal in weight, this should answer your question on the weight of the wings Pacman. They are going to get heavier once I add the carbon fibre and epoxy glue. I’m thinking at this point whether I should glass them as well….


I still need some modeling filler material to fix certain areas. This method of foam cutting will not give a perfect tapered wing, but at least I can cut successfully manually, so it’s a small price to pay, plus the extra sanding I have to do.



I left the filler to set and start to work on the stabilizer and fin. They are rounded and the plastic hinges are glued. The stabilizer with the elevators done are glued first.



Followed by the fin and rudder, all glued with Epoxy. Getting the tail surfaces perpendicular and level can be a challenge when you use 5 minute epoxy. Perhaps 30 minute epoxy will be a better choice as it gives you time to adjust.



Just can’t resist putting everything on temporarily to see what the final plane would look like. Boy I just can’t wait to see this bird fly!



Okay that’s it for this update. I’ll work on the fuselage and wings tomorrow and if I’m fast enough, this bird shall be ready for a maiden this weekend!

[weeliano]

Update 6

Tucano Build Thread update 6

Time for another photo update!

My building pace has slowed down somewhat, my original plan to maiden the Tucano on Sunday did not materialize, but I think that’s a good thing too as I’m starting to enjoy building the plane at a slow leisurely pace.

Okay the photo below shows the airfoil paper templates (that are properly resized to match the chord length of the wing at the fuselage intersection) glued to the fuselage sides. I decided not to cut the wing slots right at the beginning so that I can maintain the strength of the fuselage while I work on it.



A sharp thin exacto knife blade is used to trim it out.


Trying on the wing for a look, at this stage the wing tips are sanded.


Tucano at another angle, this time the cowling is capped. A ventilation hole will be cut later to allow air to flow to the cooling fins of the aluminum gear box.


The photo below shows how tight fitting the propeller is from the cowling.


Checking the dihedral, looking good, but after glassing, may need some adjustment.



A 1x10x300 mm carbon fibre strip is inserted to the centre of the wing and epoxied permanently. The wingtips and centre of the wing are glassed.

I should have used 30 minute epoxy for glassing as it will give me more time to adjust the glass fibre as well as squeegee excess epoxy away. This is my first attempt at glassing and I have made a little mess out of the area’s I’ve glassed. After the epoxy has set, there’s a lot of sanding to do.


Here’s the latest photo of the plane with the leading edges glassed and sanded. All the fine holes are filled with “model lite” filler. The cowling is also glassed at this stage.



Tomorrow I shall work on the ailerons and start cutting out the canopy and cowling.

Stay tuned!

[w_kby]

Wow,..that's remarkable..........

[weeliano]

Update 7

Tucano Build thread update 7

More Photos!

Alright, I’m very close to maidening my Tucano, here’s what I did over the past 2 days.

Here’s a painting method discovered by my friend Adrian, he found that Emulsion wall paints are excellent for painting foam as it fills up fine holes. After drying and sanding, it leaves a smooth finish. To apply the paints evenly, a good quality brush is a MUST. I find that high quality made in Japan nylon hair brushes are excellent for applying paint as it leaves a very consistent finish. If you use those cheap coarse hair made in China brushes, it will leave behind ugly streaks.

Here I have prepared to paint the wing after glassing, filling and sanding.



The photo shows a way to prop up the wing for it to dry, using regular plastic clothes pegs. The areas the clothes pegs are clamping are already glassed so I don’t have to put depron underneath to cushion the pegs. I left the centre without paint first as I will be gluing the wing to the fuselage permanently. Once the paint has dried, I found that you need to sand carefully as the wall paint can easily clog up the sand paper and form “paint powder balls” these can dent the foam surface as I’ve unfortunately discovered. I had to patch up the dents with more filler!


While waiting for the wing to dry, I used the sharpest and thinnest exacto knife blade I can find and carefully removed the canopy from the fuselage.


I cut a “smiling” cooling hole on the cowling, but in the end I had to cut a bigger hole so that more air can cool the aluminum gearbox fins. You must leave a hole a the bottom of the fuselage so that air can travel through.


Out comes the cowling! I had a little trouble removing the cowling as the main plastic gear was encased in the depron cavity. In the end I just simply pushed the cowling upwards and slide it out, which means I had o cut a bigger cooling air hole.


This is the plane with the bamboo retainer and thin plywood extensions already installed and secured by tiny wood screws that come free with the servos I bought. At this stage the wing is not glued and the ailerons are not cut out yet.


The ailerons are marked out, cut and rounded and the wing servo bay is constructed out of bluefoam.


Holes and slots are cut to accommodate the ailerons pushrods. I used aluminum tubes and umbrella spokes to make these. The umbrella spokes are great as they already come with eyelets on the end.


The hinges are installed and glued. The ailerons fixtures are installed and tested out for alignment. GWS glue is used to glue the servo permanently to the wing. The blue foam servo bay is trimmed a little to ensure that it fits the fuselage.


After the wing servo is installed, I proceeded to create a bluefoam servo bay for my elevator and rudder servos and installed them. The wing at this stage is glued permanently to the fuselage. After waiting for the epoxy to set, a 3mm piece of depron is cut and planked across the wing below and glassed.


Melamine foam, that wonderful material that’s great for scrubbing dirty dishes and porcelain ware is used to cushion the battery and fill up empty areas of the canopy. Melamine foam is also easy to shape with a very sharp blade.


Here’s how I installed my electronics. Velcro is used to secure the receiver to the roof of the canopy.


Just one more paint job to go before the maiden flight. Here are some pictures of the completed aircraft.








The next update will hopefully feature some flying photos or video!

[weeliano]

Peruvian Airforce Decals

Okay, it's not really an update, here are the decals I've made for my Tucano. I hand painted the shark's mouth and the tail fin decoration plus the Spanish "rescue" arrows. The only thing not hand painted are the roundels and flag which is easily available from the internet. I'm just going to print them out on sticky A4 paper and stick them on the surface of my Tucano. I'm going to use the grey colour scheme I have used for my 3D rendered tucano.

Hopefully tomorrow's morning's weather is calm for my maiden.

[shmuckerz]

WoW that is a beautifully built plane!!!
good luck on ur maiden!!!

cheers
shmuckerz

[weeliano]

Pre-Maiden Photo.

It's Done! Here's the picture of the Tucano in it's pre-maiden colours. The colour of the Tucano is actually light Grey, but the Flash made it look white.

[msc]

Great job brother!
You have a winner there.
What is the all up weight? Hope to see it fly myself. Do you fly at Punggol Field Walk?

MS