The things we do for entertainment... "Fiu"

[Epitaph]

Right... eventhough this is more a "preproject" rather than an actual project, I thought I might as well post it.

I've had my eye on a particular model for a while now, a small slope plank wing with a slight inverted sweep called the "Fiu". It's only 740mm in wingspan, but a fast little nervious thing on the slope.



This is actually the avatar of a guy on RCGroups who also made it. Hope he doesn't mind me using it, but it shows very nicely the end result.

Anyway... I wanted to make one with a couple of modifications, like clamshell speedbrakes on the tail and the wing in 2 halves, things like that. But due to the size, I found it rather difficult to imagine the exact placing of everything, like for example the extra servo and how to modify the wing. Seeing as I work better around a problem with something in my hands, I thought the best idea would be to make an original, with the only modifiction being the placement of the servos inside the wing. Now, due to limitations in aquirement of materials for this project, I am just making what I can for the moment out of material I already have, more a mental exercise at this moment. Anyway, I'm starting off with the fuselage, which I already have about half way!



I am making one small modification though, and that is a conduit for the antenna, as I still fly on 35mhz (our equivelent of your 72mhz over there). One thing I don't like about most planes is the way they were made or designed really nice, but no facilities added for the antenna, which has always ended up being "get it out however you can". This isn't a problem nowadays with 2.4ghz, but with the older equipment it was a bit of a problem than often became an eyesore. This plane is no exception, which if you look on the first photo, the antenna is just coming out throuth the wing joint with the fuselage. So what I did was make 3mm tail fin instead of 2mm, out of 2 pieces of 1.5mm, and scored a channel in the 2 halves, and stuck an interior transmision conduit inside which is 2mm in diameter. What it is is the white inner sleve that covers the transmision rods on the ready made systems. So I removed the metal core, leaving a 1mm hole down the middle... just enough to thread the antenna through, and stuck it inside the vertical fin with some epoxy. Then just glue the 2 halves togeather with some white wood glue and a bead of epoxy in the conduit groove, add a bottom fin out of some 1.5mm ply (rather than the 2mm balsa it says, as this will take the full force of the landings), and now I have a modified fin ready to add, with the conduit taking the antenna all the way up to the top tip internally from the front compartment



So that's it for the moment... one thing I am considering is on the final version giving it a 20% increase in size. This will put it into the 900mm category, and will give extra room inside for the modificactiobs, as well as justify a thicker fin for the clamshell brake, as well as an increased wing area for the extra weight, not to mention making a slightly more stable plane. And seeing as I want to make it with the wings in 2 halves, it will still be very transportable as no piece will be over half a meter long, ideal for sticking in a backpack and hiking a while, and if you find a nice slope along the way with a breeze, it all goes togeather in about 3 seconds, and on a 2S 700mAh LiFePO4 battery made out of two 14500 size elements (AA size), it will fly for hours with no need for the extra weight of a BEC or anything!

Anyway, I'm going back to bed to finish cooking this flu virus i'm currently incubating... the way I feel it might not be a bad idea to sacrifice a lamb and paint its blood on the front door!

 

[Epitaph]

One thing to add... I am thinking about making this original one with reinfirced wings with carbon fiber spars rather than the original balsa ones, making the fuselage lighter with some holes and adding a wing peg to try it out as a small DLG wing... I can probably get it to a flight weight of under 100g I think...

On the radio side of things, the final one I would like make in 2.4ghz so I don't have that antenna dragging behind it. I was thinking of getting an Orange DSM2/X module and adapting it to plug straight into the trainer port on my radios... why this system? First off, it's cheap. Second, I use 2 different radios that don't even have the same trainer port (Multiplex and Futaba), and I can still use this system even if I got a new radio later on. I can also make this system with the FrSky module to have more to choose from, and the ACCST system is VERY good indeed. If I do make an external module, I'll make a thread on that later.

 

[earthsciteach]

That is a really nice looking model!

 

[Team_Monkey]

I too have longed for a Fiu. I've had that page in my favorites for awhile. The complete lack of a good slope hill in northeast Ohio is a bummer though.

You list of mods is pretty extensive for such a small wing. I've never flown one, it just seems complicated. I think a DLG version would be great. I bought some carbon fiber tape for another project but didn't use it. Do you think laminating it in a straight line across the wing would be enough for a DLG Fiu?

 

[Epitaph]

I don't think so... The forces it has to take are pretty strong. What it needs is to be ridged from the eongtip to the root. The original Fiu is designed to have the 2mm ribs mounted between 2 5x7 balsa spars running the length of the wing. What I was thinking of is changing the 5x7 balsa spars for 4x4 carbon fiber hollow rod, and just recutting the original ribs to the new spar size, and probably out of 1.5mm balsa instead of 2mm, which has more or less the same strength but less weight. That saved weight might even allow me to cover the leading edge in 0.5mm balsa which will give a lot more overall strength. Then just add a 3mm carbon fiber peg to one wingtip next to the spars, and reinforcethe joint with some carbon fiber and epoxy/alcohol mix. That should make it strong enough. Carbon fiber tape is great for making a joint stronger in integrity, but it doesn't make it ridged and firm, which is what it would need.

The performance as a DLG I would expect it to be similar to an Alula.

And yes, there are quite a few modifications I am trying to fit in, but I do so enjoy a challenge!!

 

[Epitaph]

That is a really nice looking model!

Why don't you make one too? It's pretty easy, the plans just print out on an A3 piece of paper or 2 A4 pieces, and materials it doesn't need much... It was designed to be made mainly out of one sheet of 2mm balsa!

I was thinking of covering it in white for the fuselage, and transparent red for the wings... Simple, but makes it stand out

 

[Epitaph]

Well, the time came to put the tailfin in place on the fuselage and thread the conduit through the hole I made to the front of the plane. The angle is a little sharp at one point so I think I am going to have to stuff some vaseline down the conduit to get the antenna to go through it properly, but that's not really a problem. A little white wood glue on the wood on the fin and a little epoxy to stick the conduit in place on a couple of spots, and it's ready to be left to dry a few hours. Basically, the fuselage is more or less done!

 

[colorex]

This looks like an awesome little build. I would love to make one like this, but I'm afraid it's a bit too nervous for me. Do you think I'll be fine, or do you perhaps know of another similar plane that could be used for sloping? Maybe I'm just better off making a flying wing...

 

[Freaky_1]

Now this I like.

 

[Epitaph]

Glad you like it Freaky! Gonna make one too?

Colorex... when you say nervious, do you mean to slope a miniature wing or to slope period? I don't know if you've ever sloped before. If you haven't, then you can learn to slope with anything, just throw it up there and you get the hang of it. I myself learned to slope with a Bixler in 15-20mph winds. It's just a case of starting doing your figure 8's up and down the slope, learning how the wind acts, things like that... and don't use your motor, that's cheating! If you have sloped, then this is a good, cheap and easy one to make, but will be very nervious in the air. A plank wing on a slope acts pretty different to a traditional tailed plane, but give a very fun and unique experience. If you wanted to go for something a little bigger, I've seen very good things from the "SALy", whkch is basiclly a balsa Alula, but on a bigger scale. A friend has straight wing plank about 1.4m in width which flies VERY good, called the Crow, but it's not so much a design that's distributed, more like a concept of size and aerofoil, and each makes the final design to their taste within those boundaries. The usual thing is, the smaller it is, the more nervious it is, and plank wings are no exception! My advise, seeing how cheap and easy this one is to make from scratch, you have nothing to loose by trying! One thing I would think about, and for myself too, is I might try one of those Orange Rx's in it with the flight stabilization system, because if there's one thing you get a lot of on the slope, it's unexpected gusts.

--------------------------------------

Got the glue nice and dry, so I tried out the conduit... IT WORKS!

I have the plane back on the bench drying right now again with some belly encasing, going very well indeed. I'm usually a slow builder, but this build so far has taken me just 2 days... if I had been a fast builder and was making the wings at the same time, I think I might even be covering right now! It is just such a quick and simple build to make... just a shame some materials like servos, covering iron and carbon fiber rods are going to hold me back until I can afford them...

Anyway, quick pic of the triumphant antenna

 

[Freaky_1]

Don't think my skills are up to something so small for what little sloping experience I have. Might try a foam version and test myself though. Would be a fairly simple matter to move on to balsa afterword me thinks.

 

[ViperTech]

Nice looking bird! I have no where near enough skill to build that let alone fly it! I really don't know much about slope soaring it looks cool though! Good luck with the build!

 

[Epitaph]

Freaky, it's all really a case of what we're used to, and I grew up with wood so I find it easier to use. But it is an easy build, I mean, as I said, I've been just 2 days on it. Balsa scratchbuilding is something I would only really recommend to those that like to build as much as flying. Cutting the pieces and sanding takes time and a good pulse, gluing needs time to cure, which you can cheat with CA, but it doesn't give the same results and takes the fun out of it. You need to learn to handle the covering well and how to iron it and tense it properly... you don't balsaboild just to go out and fly, you balsabuild to enjoy the process, and THEN go out and fly.

Thanks Viper! Sloping is something that can be as easy or as hard as you like really... just the one key factor needed: a slope! It's not hard to get into, as I said, I learned with a bixler just doing my figure eights up and down. The key thing when starting is to never turn into the slope, always away. So if you are going south and youwant to turn into the north leg, and the wind is coming up the slope from the west, you turn west into the wind, not east... hence the figure eights. You learn very quickly how the wind works that way, and it's just a case of building up from there. I bet everyone on the slope must have thought I was one really crazy woman sloping with a bixler but it works!

Another good thing about learning to slope, is seeing as figure eights are almost compulsary, it's a great way of helping to cure that "left hand turn syndrome" most fliers tend to develop!

 

[colorex]

Glad you like it Freaky! Gonna make one too?

Colorex... when you say nervious, do you mean to slope a miniature wing or to slope period? I don't know if you've ever sloped before. If you haven't, then you can learn to slope with anything, just throw it up there and you get the hang of it. I myself learned to slope with a Bixler in 15-20mph winds. It's just a case of starting doing your figure 8's up and down the slope, learning how the wind acts, things like that... and don't use your motor, that's cheating! If you have sloped, then this is a good, cheap and easy one to make, but will be very nervious in the air. A plank wing on a slope acts pretty different to a traditional tailed plane, but give a very fun and unique experience. If you wanted to go for something a little bigger, I've seen very good things from the "SALy", whkch is basiclly a balsa Alula, but on a bigger scale. A friend has straight wing plank about 1.4m in width which flies VERY good, called the Crow, but it's not so much a design that's distributed, more like a concept of size and aerofoil, and each makes the final design to their taste within those boundaries. The usual thing is, the smaller it is, the more nervious it is, and plank wings are no exception! My advise, seeing how cheap and easy this one is to make from scratch, you have nothing to loose by trying! One thing I would think about, and for myself too, is I might try one of those Orange Rx's in it with the flight stabilization system, because if there's one thing you get a lot of on the slope, it's unexpected gusts.

Gracias por la extensa respuesta!

I have sloped on a beach, over a 3-4 meter high cliff. I did it with my Bixler, and it was pretty easy, although fast! I get what you mean, when you say nervous due to size. I was concerned more about weight - I don't know what I'll use for battery... I have several 600mAh 1S batteries, maybe make 2S out of them and power the receiver directly. I have a broken antenna receiver to test the voltage (excess) on.

I check now and the R615 should take the extra voltage... how about the 9gram servos...

Input voltage: 3.7~9.6V

I may just go ahead and do this, just because of the simplicity of the build!

The only issue I have, is that I have no covering film source nearby, living in a small city in Ecuador where the RC hobby does not pass the toy level.

I will have to experiment with other covering methods if I do this.

 

[Epitaph]

On DealExtreme there are packs of four 14500 (AA size) 1S 700mAh LiFePO4 cells for under $12US with delivery included. You can use 2 of these to make a 2S battery with a voltage of 6.6V to plug straight into the receiver and the whole pack would weigh just a little more than 2 AA cells and take up the same space. Covering is a little harder if you can't get it easy. Before shrink covering, we used to use japan tissue paper to cover it coated in "novavia" varnish. What you do is place the paper over the wibg and paint a small amount of novavia dileuted over the ribs and spars, and this would glue it to place. After it is dry, you paint the entire lit with the novavia, and this would make the paper absorbe it and the fibers would bond closer togeather, literally shrinkwrapping it. Then just paint the colours you wish. Maybe these materials are easier to find over there.

Another thing you can try is the covering used to protect text books... glue it to the spars and ribs, then use eitheran iron or a hairdryer to shrink it... it won't shrink much, but it will be enough. This is used a lot to cover ultra light indoor aircraft.

The best thing though if you want to really start to get into balsa builds there is to find a way of getting covering. I think HK do it, but I'm not sure if they do... also, I don't know what import is like over there. It might be an idea to contact the guys from FliteTest Argentina, as they may have encountered the same problem and found a solution that could work for you too... maybe latinamerican countries have some sort of postage agreement amongst each other that you're not aware of.

Buena suerte con el tema! Voy a pegar el morro para que pueda ir curandose, y a la camita ^.^

OYASUMINASAI MINA-SAN!!

 

[Epitaph]

Also, if you want to try something light and small on a slope on days of very little wind to get used to small slopers, Multiplex make a small, 500mm wingspan freeflight chuck glider called the Fox. There are many others that make it too, like Graupner with a T tail, Dynam the same as the Fox... even Hobbyking make one with a V tail! The thing is they are really cheap (the MPX being the really overpriced one at about €15, but the HK one is about $5), and you might be able to find one similar in some store over there. What you do is measure the CG, then take the cabin off, and "empty" out the cabin area. They usually have a small ballbearing in the front for CG reasons. Then you cut the wings flush on the root, and push a carbon rod through the fuselage where the CG is. Then push the wings onto it, leaving you with the wings so that they can twist on the spar. Then get two 3.7g servos that will work with 1S and cut a recess out in the fuselage in such a way that the arms on their neutral 90° position line up with the leading edge of the wing in its neutral position. Then you place a headed pin through the servo hole into the wing, but with the wing abouta milimeter seperated from the fuselage to allow for the circular movement of the servo. Put a small receiver in the cabin along with a small 1S LiPo, add a little weight if needed for CG, and program the radio for an elevon configuration with very small throws. Congratulations! You have a micro pitcheron wing sloper that cost very little money and a couple of hours work!

 

[colorex]

On DealExtreme there are packs of four 14500 (AA size) 1S 700mAh LiFePO4 cells for under $12US with delivery included. You can use 2 of these to make a 2S battery with a voltage of 6.6V to plug straight into the receiver and the whole pack would weigh just a little more than 2 AA cells and take up the same space. Covering is a little harder if you can't get it easy. Before shrink covering, we used to use japan tissue paper to cover it coated in "novavia" varnish. What you do is place the paper over the wibg and paint a small amount of novavia dileuted over the ribs and spars, and this would glue it to place. After it is dry, you paint the entire lit with the novavia, and this would make the paper absorbe it and the fibers would bond closer togeather, literally shrinkwrapping it. Then just paint the colours you wish. Maybe these materials are easier to find over there.

Another thing you can try is the covering used to protect text books... glue it to the spars and ribs, then use eitheran iron or a hairdryer to shrink it... it won't shrink much, but it will be enough. This is used a lot to cover ultra light indoor aircraft.

The best thing though if you want to really start to get into balsa builds there is to find a way of getting covering. I think HK do it, but I'm not sure if they do... also, I don't know what import is like over there. It might be an idea to contact the guys from FliteTest Argentina, as they may have encountered the same problem and found a solution that could work for you too... maybe latinamerican countries have some sort of postage agreement amongst each other that you're not aware of.

Buena suerte con el tema! Voy a pegar el morro para que pueda ir curandose, y a la camita ^.^

OYASUMINASAI MINA-SAN!!

I am waiting on two delayed orders and don't wan to place another to get it 4 weeks later... I'll find a way. 3x AAA maybe?

I have bought plenty of tissue paper and made a balsa model with it two years ago - but have not found dope. Maybe some kind of varnish will work?

http://flitetest.com/articles/Baker_McMillen_Cadet_II_Scratchbuild

I'll look into the text book covering - may not be the same, but I can try. I think there may be covering available in the bigger cities, but there is not really an efficient purchasing method, except for going there at 4 and 8 hours respectively.

Ordering from outside works for me (despite looong wait times) but it is not an option right now due to my economic situation.

Thanks for the tips anyway! Arigato gozaimasu!

 

[Epitaph]

Ahhh... one last thing before I go to bed... the plans on the website are for the ’90s version with the servos in the forward fuselage and rods going to the back, which is a pain in the backside when dismantling or putting it togeather, as well as very space limited for movement. But look at the build photos on the page, as he later modified the system to have the servos insode the wing which is a much better idea, arbeit still with the same pushrod system. So if you download the plans and see the original headache there, know that there are better ways documented. I personally am going for some microservos from Turnigy that are just 8mm thick, the wing being 11mm on the widest part. This will give enough space for the arms to work internally as throws are minimal so the innermost hole will work fine, and use transmision cables like I used on the Coyote wing all internally, so no messing with pushrods in the tight space of the aft fuselage. You can also see how old the plans are from the Sanyo ⅓A 170mAh cells, the old AM 2ch Futaba Attack receiver and the V-tail mixer used, not to mention servos that have long since dissapeared!

Y ahora si que colorin colorado, este cuento se ha acabado... por hoy!

 

[Epitaph]

For 3AAA batteries you might as well just use the 1S LiPo which will give the same voltage and less weight... not worth it.

 

[colorex]

Ahhh... one last thing before I go to bed... the plans on the website are for the ’90s version with the servos in the forward fuselage and rods going to the back, which is a pain in the backside when dismantling or putting it togeather, as well as very space limited for movement. But look at the build photos on the page, as he later modified the system to have the servos insode the wing which is a much better idea, arbeit still with the same pushrod system. So if you download the plans and see the original headache there, know that there are better ways documented. I personally am going for some microservos from Turnigy that are just 8mm thick, the wing being 11mm on the widest part. This will give enough space for the arms to work internally as throws are minimal so the innermost hole will work fine, and use transmision cables like I used on the Coyote wing all internally, so no messing with pushrods in the tight space of the aft fuselage. You can also see how old the plans are from the Sanyo ⅓A 170mAh cells, the old AM 2ch Futaba Attack receiver and the V-tail mixer used, not to mention servos that have long since dissapeared!

Y ahora si que colorin colorado, este cuento se ha acabado... por hoy!

I noticed the torque rods... they are annoying. I'm glad there is a way to avoid them.

I only have 9 gram servos, I hope they will be fine...

I noticed that the plans were a bit old! 2 channels only. I googled those servos to know the weight, but didn't find anything. The shiny PDF files confused me as they look quite recent.

I found 2 pieces of 2-3mm balsa - should be enough to make the whole thing, maybe even two! A little warped though... shouldn't matter much.

See you tomorrow! Hasta mañana!