RC India

Hi Friend.
I am trying to make a Skysurfer from High density Thermacol.
This will be approx, dimension of skysurfer.
The hd thermacol bought of 80 mm and 46 mm.  80 for fuse and 46 will be for wings.
Thermacol dimensions are 1000x500x80 mm and 1000x500x46 mm.

started on 26/3 , but could not upload .

Here are some pics from beginning.

Note:- The fuse is completely cut with knife and then sanded to that shape.

Tried making wings by sanding the thermacol , but it was too difficult to get the same shape as real skysurfer wings , and needs lot of time to sand the entire sheet. So now i  have to cut the wings by using hot wire cutter. Plz help to make hot wire cutter.

Read some posts on Hot wire cutter and tried local electrical shops. they says that using transformer is not a god idea, it cannot sustain and will blown out ????
need real help.....any one knows much better idea or already made one plz help.

Thanks

oooh... nice looking thermocol.... ;D

you can use guitar string to create it...
why dont you try to cut a rough shape of the wings with a (very) large blade (hot).... and then sand it down with a sheet of sandpaper attached to a block of wood... so you get a large sanding area....

Thanks aniket.
Is there any option for guitar string, as there is no musical shop near to me.. Way 20 km away. :(

Easiest way is to get a thin GI wire(about 15cm) and hook it up (with thick insulated wires at each end of the GI wire)to a computer smps on the 5V rail. You can substitute the smps with a wall charger which outputs atleast 3A. Voltage will decide how long a wire you can use.

Wow nice Build...
I am using heater coil with my old laptop charger
16v 4.5A charger.. Works very nice.. need to give some tension to the string using spring or something and cut of the power soon after the work done.. heats in seconds... :)
Good luck

@ lastrites:-Thanks will try that surely.
@ Arun:-  heater spring is not getting straight , i  holds its curves ...

can i use my dell lappy charger ??? it is written output as 19.5v at 3.34 A.
Does using it for heating the wire, can damage the charger itself ??

Swizera, do NOT use the dell lappy charger, it is not ment for resistive loads and will fry itself, trust me I've descovered this the hard way :-).....for the wire you can use the nicrome wire from a 1000w ROOM heater element, not the one use for cooking(I think this is what Arun ment)

for power supply get a step down transformer, with output voltage between 15-30V and current rating between 3-5 amps.....these are known as audio transformers at my place and cost around 250 to 300 INR......just hook up a dimmer switch in series with the primary coil of the transformer and connect your bow to the secondary coil with a limiting fuse in between if you like, and you are good to go

I use a 48" long bow for cutting wing cores and it draws around 3-3.5 amps at about 25 V

Thanks a ton Bilal, u saved my lappy charger...
I will search for audio transformer, as u said.
It will be a great help if u post a pic of the connection( from tansformer to dimmer to coil etc ...).
because i am zero at electrical.  A detailed pic will be very helpfull.

can we use fan dimmer ?

Thanks
Manoj

ofcorse you can use fan dimmers, tat's what I am using, but try to get dimmers that are made for lamps aka light bulbs, they handle resistive loads better, else any dimmer would work, just take care of the wattage it can handle

I don't have the pic of my setup ritenow, will a crude circuit diagram thing work.....I can draw one in paint :-D

Yes bilal plz give the crude diagram. will work for me.

I have bought 12 volts 3 Amp transformer and tries to heat, heater spring after straitening it . the wire is getting hot but not so much to cut the thermacol neatly . plz suggest what to do , without it cannot complete the  plane ....

plans please for the fuse!!

Hello swizera i remember you following my build log for a axn lookalike....!!!!
Go for a 12volt 5 amp transformer and a normal GI wire with a normal fan regulator at the primary of the transformer... this is easy part but how you are going to cut the wing is tough.

Do you plan to cut wing from perpendicular to chord or leading/trailing edge.... i had cut the wing perpendicular to chord then sanding with sand paper.

do buy cheap thermacole to try and practice first or else you will finish your high density in experimenting !!!!

Thanks Saurabh, really its too dificult to cut the wings . i already wasted money in buying 3amp 12 v transformer. :banghead:. i didnt found 5A transformer here.
Is there any other method to cut the wings ?
I also tried to making the wing by sanding , but not getting correct shape .. :(

Manoj

Try using a thinner wire if you can get one. Decreasing the length of the wire, if you can, may help also. If you can't get a 5A one, get another 3A one and put its output in series or parallel with the others output.

@ Last rites , i am noob in putting these in parallel or like that . plz  if can u just put a rough diagram of how yo put in series or parallel.

Swiz you can do your job with this 3A... get some heater wires and make the length small as possible.. will cut nicely... if you are planning for full length cutting at a time.. you may want to consider buying a more A transformer... like I use a 16v 5A one.. works good...


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swizera, even i work with 3A transformer.  I use the wires stripped from 35 watts soldering iron.
If you are intended to use, use with fan regulator in series.