Tiny Curare
07-15-2013, 02:18 AM
#26
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RE: Tiny Curare
Just curious, did you see the 1/2A sized Curare thread by Mark Rittinger? I built 2 but am too chicken to fly them.
Keen to see someone else do it. Was a simple enough design. The thread's in RCG.
Keen to see someone else do it. Was a simple enough design. The thread's in RCG.
07-15-2013, 04:39 AM
#27
Thread Starter
RE: Tiny Curare
dchuah
I have reviewed an electric version of a 1/2 A curare thread but can't remember whose it was. he didn't use landing gears but I have to use cos we just have some few grass fields, and this imposes a heavier structure.
Ehsan
I have reviewed an electric version of a 1/2 A curare thread but can't remember whose it was. he didn't use landing gears but I have to use cos we just have some few grass fields, and this imposes a heavier structure.
Ehsan
07-15-2013, 05:12 AM
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RE: Tiny Curare
Ehsan,
You sure do some great looking building. Those skins look like they were born on the wings. Keep the pictures coming. Ihope I can do as well.
John
You sure do some great looking building. Those skins look like they were born on the wings. Keep the pictures coming. Ihope I can do as well.
John
07-15-2013, 05:18 AM
#29
Thread Starter
RE: Tiny Curare
I use this step by step procedure to shape L.E.
1) a line must be drawn on the L.E which indicates the linear axis of the ribs,note this line is not necessarily the symetric line of the balsa spar used for L.E. but must join the symetric line of the wing's profile. this line guides you while carving the L.E. to know if you are carving toomuch or not.
2) to prevent any erosion on the skin caused by cutter I simply use a piece of tape at the tip of the blade to make a safe end blade.
3) L.E. is carved while the face of the blade is laid back on the skin. it's important to touch the skin with the face of the blade otherwise you will over carve the L.E.
4) a piece of tape is attached to the skinapproximately 1/8'' far from the L.E. this protects the skin from over sanding. thenL.E. must be sanded along with the the skin while sand paper touches the tape attached to the skin.
5) tapes are now removed and the rest of the L.E. is sanded equal from top and bottom of the wing regarding the center line drawn at the first step.
Ehsan
1) a line must be drawn on the L.E which indicates the linear axis of the ribs,note this line is not necessarily the symetric line of the balsa spar used for L.E. but must join the symetric line of the wing's profile. this line guides you while carving the L.E. to know if you are carving toomuch or not.
2) to prevent any erosion on the skin caused by cutter I simply use a piece of tape at the tip of the blade to make a safe end blade.
3) L.E. is carved while the face of the blade is laid back on the skin. it's important to touch the skin with the face of the blade otherwise you will over carve the L.E.
4) a piece of tape is attached to the skinapproximately 1/8'' far from the L.E. this protects the skin from over sanding. thenL.E. must be sanded along with the the skin while sand paper touches the tape attached to the skin.
5) tapes are now removed and the rest of the L.E. is sanded equal from top and bottom of the wing regarding the center line drawn at the first step.
Ehsan
07-17-2013, 05:19 AM
#31
Thread Starter
RE: Tiny Curare
More progress but too slow.
Cap strips are now placed, and the excess balsa is removed from the tip of the wing.
I prefered to use bicyclespokesrather than original model linkage for aileron, costhey're made of harder metal, thus canwithstand more tortional stress. today I added more images instead of talking about what I did. I think these images can speak better than me.
Ehsan
Cap strips are now placed, and the excess balsa is removed from the tip of the wing.
I prefered to use bicyclespokesrather than original model linkage for aileron, costhey're made of harder metal, thus canwithstand more tortional stress. today I added more images instead of talking about what I did. I think these images can speak better than me.
Ehsan
07-17-2013, 05:30 AM
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RE: Tiny Curare
Maybe slow, but your workmanship is great. Keep it coming, I found a print shop that can print a dwg file yesterday, going there today and get my plans printed.
John
John
07-17-2013, 08:52 AM
#36
Thread Starter
RE: Tiny Curare
Thanks Ralph,
It is better to use bushing any bushing may add more weight to the plane. instead of bushushing - in this size of plane- I usually bend a pin to " U " shape and attach it with some C.A. to prevent any unfavorable movement of the torque rod. in the images below you can see this method I used in my New Era 3 .
Ehsan
It is better to use bushing any bushing may add more weight to the plane. instead of bushushing - in this size of plane- I usually bend a pin to " U " shape and attach it with some C.A. to prevent any unfavorable movement of the torque rod. in the images below you can see this method I used in my New Era 3 .
Ehsan
07-17-2013, 04:06 PM
#37
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RE: Tiny Curare
Minor comment,
As a general rule its not a good idea to print scale independent files at a print shop. DWG (and several other CAD format) files don't have a built in scale meaning that the printout (paper space) size can be set at the moment of printing. What this means is that it is a less reliable format when dealing with generic print shops where the expertise may be limited. That said, a facility that is used to dealing with architectural and engineering printing on a daily basis should be able to handle the job and deliver the correct printout.
Still, I personally prefer to minimize the variables and provide a "scale locked" file format to the repro shop. That way, if there is a mistake, it is easy to point out the mistake is on their part and have it corrected. The ideal file format for this is PDF although postscript (PS) or encapsulated PS (EPS) are very similar but mostly deprecated.
On plans I draw, in addition to the scale, I like to include a "plan frame" indicating its size to easily verify printout.
In short, it is fairly straight forward to produce the PDF from the DWG source at the desired scale and then send that to the printers.
David
As a general rule its not a good idea to print scale independent files at a print shop. DWG (and several other CAD format) files don't have a built in scale meaning that the printout (paper space) size can be set at the moment of printing. What this means is that it is a less reliable format when dealing with generic print shops where the expertise may be limited. That said, a facility that is used to dealing with architectural and engineering printing on a daily basis should be able to handle the job and deliver the correct printout.
Still, I personally prefer to minimize the variables and provide a "scale locked" file format to the repro shop. That way, if there is a mistake, it is easy to point out the mistake is on their part and have it corrected. The ideal file format for this is PDF although postscript (PS) or encapsulated PS (EPS) are very similar but mostly deprecated.
On plans I draw, in addition to the scale, I like to include a "plan frame" indicating its size to easily verify printout.
In short, it is fairly straight forward to produce the PDF from the DWG source at the desired scale and then send that to the printers.
David
07-17-2013, 08:14 PM
#38
Senior Member
RE: Tiny Curare
Dave, a few months ago I think it was you who posted plans for the Kaos. I have access to a plotter at work so I made a full size copy....
But before doing that, I also made a scale copy on an 11x17" sheet. That has to be the cutest tinsy weensy Kaos ever, that can probably be flown with hardware fromthe old SU26 foamie(H9 issue). It has about a 15" span. One of these days I may build the Kaos Pico, all foam of course...
But before doing that, I also made a scale copy on an 11x17" sheet. That has to be the cutest tinsy weensy Kaos ever, that can probably be flown with hardware fromthe old SU26 foamie(H9 issue). It has about a 15" span. One of these days I may build the Kaos Pico, all foam of course...
07-19-2013, 09:10 PM
#40
Thread Starter
RE: Tiny Curare
Hi every body,
wing tips are now completed, they are made out of 1mm thick hard wood sandwiched between 2 layers of 10mm(3/8") balsa. then shaped to the airfoil.in this stage it's alittle bit bigger than the wing's profile at the tipof the wing. the blocks were hollowed by the means of a low speedhandpiece and a carbide bur. then wereattached to the wing with some epoxy. carved to exactly fit the wing. and finaly sanded gradually from large to fine grit sandpaper to shape its proper shape.
Ehsan
wing tips are now completed, they are made out of 1mm thick hard wood sandwiched between 2 layers of 10mm(3/8") balsa. then shaped to the airfoil.in this stage it's alittle bit bigger than the wing's profile at the tipof the wing. the blocks were hollowed by the means of a low speedhandpiece and a carbide bur. then wereattached to the wing with some epoxy. carved to exactly fit the wing. and finaly sanded gradually from large to fine grit sandpaper to shape its proper shape.
Ehsan
07-29-2013, 04:42 PM
#41
Thread Starter
RE: Tiny Curare
Hi again guys,
I was really busy in the past 10 days and was not home to work on the wing but last night I got enough time to finish the wing by making ailerons.
asitcould beseen in the images I do this by using 2 strips of 1mm balsa to make a hollowed aileron and save some grams. some triangular ribs were used in the structure, strengthening the aileron and bringing a higher tortional resistance. unfortunately I forgot to take photos of theses ribs glued in place.a small triangular balsa block wasusedto support the aileron torque rod as well.finally the wing tip and the tip of each aileron was beveled based on the plan.
Ehsan
I was really busy in the past 10 days and was not home to work on the wing but last night I got enough time to finish the wing by making ailerons.
asitcould beseen in the images I do this by using 2 strips of 1mm balsa to make a hollowed aileron and save some grams. some triangular ribs were used in the structure, strengthening the aileron and bringing a higher tortional resistance. unfortunately I forgot to take photos of theses ribs glued in place.a small triangular balsa block wasusedto support the aileron torque rod as well.finally the wing tip and the tip of each aileron was beveled based on the plan.
Ehsan
07-30-2013, 01:56 AM
#42
Thread Starter
RE: Tiny Curare
Starting the fuse by preparingthe sides from 2mm balsa.before cutting the sides I decided to angle the firewall. this way it would be very easy to mount the TT GP 07 whichis able to be mounted from the back plate. any corrections in thrust anglescould be done bysome washers addedbetween backplate & firewall after the firs flight.
as it is clear in the images the down thrust was reproduced by drawing thrust line on the planand another line vertical to it where the firewall is located. Right thrust angle was reproduced in the same way , and this cause a shortened right side in comparison to the left side of the fuse.
Ehsan
as it is clear in the images the down thrust was reproduced by drawing thrust line on the planand another line vertical to it where the firewall is located. Right thrust angle was reproduced in the same way , and this cause a shortened right side in comparison to the left side of the fuse.
Ehsan
07-30-2013, 08:01 AM
#43
Thread Starter
RE: Tiny Curare
I'm working on the formers, for saving more weight I decided toreplacethe balsa blocks ( NBD2)used in the lower border of the nose with trianglar or square longerons. on the other hand the nosegear will be attached to the firewall with control horn instead ofthe fixed gear screwed to the 1/8'' PLY at the bottom of the nose as described in the plan.
Ehsan
Ehsan
07-30-2013, 10:44 AM
#44
Thread Starter
RE: Tiny Curare
I guess I'm done for tonight. All formers are prepared except firewall. next days I'll work on other part to prepare an almost custom fuse kit.
Ehsan
07-31-2013, 06:18 AM
#45
Thread Starter
RE: Tiny Curare
More progress Today
Longerons are now in place and every thing is ready to reinforce the sides by 75gr cloth and epoxy. First, I made a template as a pattern to cut the cloth. I usually wet balsa sheets with epoxy by the means of visit cards. You can spread epoxy in a thin layer by rubbing it with the card. Then I laid down the cloth and againapplied a little epoxy on it.
I don't know is it only my problem or you guys face it too. Every time I plan to mix some epoxy I'm affraid of insufficient resin but after work is done there is always alot of unused resin in my mixing cup. Today I mixed 10 ml resin and almost 6 mls were used.
Ehsan
07-31-2013, 12:48 PM
#46
Thread Starter
RE: Tiny Curare
The excess cloth must be removed while the resin is in its plastic stage .This could be determined when it isn't sticky anymore. Cutting the cloth before this stage will detaches cloth from balsa sheet. On the other hand if cutting the cloth is post poned after plastic stage -ie post poned to elastic or brittle stage - of the setting resin this will produce microcracks in resin just beside the cutting line. these craze or cracks could be recognized by a whitened resin beside the cutting line and this tells that the cloth-resin and balsa are detached and a bulged edgewould be the result. this whitened epoxy could not be removed by sandingbecause any sanding procedure cracks more resin and this reflects the light more irregular and you'll see that the small white line is getting bigger. so don't sand it and just seal it with some CA or rarefied epoxy to preventmore detachment and accumulation of oil, fuel,etc beneath the cloth-resin.
Ehsan
Ehsan
07-31-2013, 04:29 PM
#47
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RE: Tiny Curare
Very nice work Ehsan! 
I really like your idea of using glass cloth to strengthen the fuselage. I normally use plywood doublers, but I think I'll give your technique a try on one of my current projects.
Ralph
I really like your idea of using glass cloth to strengthen the fuselage. I normally use plywood doublers, but I think I'll give your technique a try on one of my current projects.
Ralph
08-01-2013, 01:44 AM
#48
Thread Starter
RE: Tiny Curare
Ralph,
Tthanks for all the kind words.
I bellieve if you try this method you won't regret your decision. I learned this from a guy whohas beenmaking molds of differnet type of aircrafts for almost 30 years.
glass cloth instead of ply doublers provides more room for equipments specially in smallen classic patterns with theirnarrow profile which enough room for tank is always a challenge for me but this does not mean that it justcould be used only in small birds. you can use iteven in yourbigger planes with no problem.moreover it is much lighter than ply , fuel proof and resistant to cracks in different directions depending on the texture of the cloth you use and you will never be concerned of delamination of the PLY just where joints to the formers duringshockingloads.
As you know while using PLY doublers it is needed to reduce the width of the formers that are going to be glued to the doubler in order to prevent anover contoured fuselage on the sides, but glass cloth adds an ignorable thickening to the sides therefore I do not reduce the formers widthbecause I squeezeout any excess resin with the visit cardand perhaps just a slight sanding of the formers is all I need.
Ehsan