Its been long time since I post anything on RCI!!!!!

Was building bigger Alula so thought of making it my entry for sweepstake!!!

After enjoying night flying with my earlier 50" Alula, I decided to make bigger one.
http://www.rcindia.org/electric-planes/biofoam-50%27-alula-powered-swept-forward-flying-wing/
Last one was KfM2 airfoil, and now wanted to make full airfoil, MH45. So decided to do hotwire Cut with HD thermocol.
It is actually swept forward wing having really good flying characteristics. Planning for completed 66" wingspan this time...
Hotwire cut was totally unexplored area for me, so started building bow...
But thanks to Rahul Roy, I borrowed is Bow and his complete setup for hotwire cutting...
Bought few HD and normal Thermocol, wasted almost 4-5 sheets while practicing, u need 2 people to operate it!!! 

Draw scale diagram of airfoil in Corel Draw and then Laser cut airfoil on 3mm veneer Ply, as u can see it in picture!!!!
Used my earlier plan as guideline for the new bird.
Using HD thermocol, after cut both wings are weighing only 170gms

Some wastage and finally was able to succeed

SOme more

Finally was able to cut it

Here is 2 piece wing

awesome work on the wings!! keep it up!

Beautiful!

Very good .... thats a huge wing. how are you planning to strengthening it ? covering with glass fiber? or paper ....

Very beautiful

lovely log of the construction..... Have loved the Alula a lot for sometime..but am at a loss of how to build it.... can you please share your drawings and methods with us here please....

Look at the cross section of those wings!!! This guy is a master cutter.

A tip for hot wire cutting... i am sure you must be having issues at the trailing edge.. it must have been too thin....

Keep the trailing edge of the template little out if the HD foam, say 1/2 centimeter... you will get very clean trailing edge.

Yes VC.... I too saw this and am happy that there is someone who can teach at least me how to cut HD thermocol...  I stopped cutting HD Thermocol when I spoiled 2 wings.  I am back to sanding out HD thermocol...

AshJR.... do let us know how do you cut thermocol.... detailed pictures and a tutorial on how to do it... it will be of great help to many of us including me...

Thanks guys!!!

Hey VC, thanks for the complement, seems like u forgot me, was away for sometime!! 

@rastsaurabh, I am planning to use aluminum C channel as spar and also planning to make it detachable 2 pieces, let see how it goes   
@shobhit17, about drawing it is posted in my earlier thread, link mentioned in the 1st post. you can use it to make your own bird. full PDF and A4 also attached in that thread.
These wings are cut using hotwire cut and believe me I wasted almost 3 HD sheets and 4 Normal Thermocol sheets while practicing...
lekin Kida mara nahi....i wanted to do it.....no matter what!! 

For hot wire cutting, I think Rahul Roy has created some good thread..let me check

found it: 
http://www.rcindia.org/electric-planes/my-experiment-with-a-scratchbuilt/

Fellow modelers have a look here ....... a tutorial for hot wire cutting ...

http://www.rcindia.org/for-sale/wing-core-made-of-high-density-thermacol/msg154985/#msg154985

Ashish what are the plans for the tail? I honestly hope you up-size it by atleast 20% compared to the last build.

Good to see you Ashish back posting here

Great wings ..... Good going ... All the best

Hey Rooster thanks!!! how u doing man...long time!!!! any boat for Sweepstake!!!
@SLS, ya i can try that!!! but chances are, that it might look out of proportion!!!! if i increase surface, can also put rudder.... can think of it!!!! but as per our discussion earlier, I need to figure out how to make airfoil on tail....will that really help!!!

Thanks Ash... guess I reverted back to good old sanding block and gave up the hot wire cutter... I was using a bamboo bow with the Guitar E string and my inverter battery as power source. Lets see how it goes the next time.... But still you please give ur expert tips on the issue of hotwire cutting to us... Thanks for the info on the plans.. Will surely look at them.
regards
Shobhit

Ash, I did some searching but was not able to find anything that supports the theory of having a symmetrical airfoil on a vertical stabilizer would be of any significance. So i guess a simple strong tail with a smoothed out leading edge should be fine.

Well... dear SunLikeStar.... the symetrical aerofoil on the fin is given so that it has equal forces from both the directions... of you give semi symetrical it will produce a directional force (lifting force) from that side of the aerofoil... well all aeroplanes have a strictly symetrical aerofoil.... For you if you wish you can just keep the fin straight and round off the edges.....  This way it though it will not be an aerofoil but will give the desired stabilising effect.  This may have higher skin friction drag but it is OK for a model...... for an aeroplane it will be terrible.

nicely done !

Quote from: shobhit17 on March 19, 2014, 09:05:05 PM
the symetrical aerofoil on the fin is given so that it has equal forces from both the directions... of you give semi symetrical it will produce a directional force (lifting force) from that side of the aerofoil

We already know that we require fully symmetrical or a flat surface. And I'm pretty sure no one would want to use a semi symmetrical airfoli as a vertical stab. But what we were actually interested in is the kind of airfoil (as in which fully symmetrical airfoil) used and the impact of different airfoils on flying characteristic. Not to mention the a flat surface with rounded edges is also a fully symmetrical airfoil. Even better is a rounded leading edge and a tapering sharp trailing edge. And after all I have a couple of very good gliders and both have vertical stabs with rounded leading edge a slightly thinner trialling edge. I wonder if there is a name to this airfoil.