RC India

Hello guys, I had started construction of a skysurfer inspired plane from coro... Please have a look and give me any sugessions...
 :hatsoff:

P.S
Its wing is still short as I am yet to add tip dihedral
its 3 feet wingspan and 3 feet fuse length...
I'll make the wingspan 4 feet after adding tip dihedral

 I have used a aerofoil type vertical tailplane...

Azad, don't make the tail fuse too long, it will be very difficult to balance the plane at CG position.

shall i chop off some length of the fuse? or shall I devise a method af mounting the wing further behind?

better chop off some.

ok let me do that...

chopped off ~ 4 inches from the rear...
Now I guess this is a smaller plane so 3 foot wingspan will do for it...

Looking good :)

It was necessary to reduce the size of the fuselage. Usually, it should be 70-80% of wingspan(though not always necessary)
Secondly, I would like to point out towards the sharp edges. Since, this is coro and now fuse is almost done so it would be difficult but, try to make the edges smooth. Sharp edges create unnecessary drag. This must have been done while cutting the fuselage out of coro sheet. But, still you can give it a try.

 :hatsoff:

Have you designed this yourself or used some reference source. Mention about the chord length. Also, what power setup you are planning to use for this.

I plan to use 1000 kv or more motor with 25 amp esc...
also I'll use 2200 mah lipo.
I can make the edges a bit more smooth but too much is not possible
 chord is 7 inches

any new ideas for control surfaces that can be made out of 2mm coro?

Great work Azad
2mm coro itself is weak for ailerons, bulges.. you might want to strengthen them using wire (wire used for pulling electrical wires through conduits is very strong)...A single insert close to the hinge should do the job, or just double the coro for ~4mm

All the best
GS

Good work Azad...
By the way what's the prop you plan to use?

Thank you sirs,
Some drastic, unexpected changes over here.... :o

The fuse became very heavy... :banghead: I was also suspecting some tail heaviness... motor mount would be very brittle on the previous fuse..
My solution...Discarded the old fuse... wing was retained as it came out very well

I guess it will be better to join the empennage via a strong, lightweight boom to the fuselage.

Wing tips are made so as to increase the wingspan to 4 feet but aren't yet joined to the wing...

Ailerons are made using 2mm coro doubled to make 4 mm coro...probably i will put in some bamboo skewers in the ailerons to reduce fluttering

Current weight of the wing and wingtips together is shown below
The peice of coro lying there is the template for the fuse...

I plan to use 8 inch prop...

What to use for the boom?

you could try round aluminium pipe for the boom, its pretty light and easily available at hardware stores.

Srinivas
Try a carbon tube boom like on my RCTLG.
From nose to tail.
Prevents fuselage from breaking in a crash!

topalle


this is going to be a very safer airplane for the equipment , as motor is in pusher configuration make both motor and prop in safe condition


best of luck for the design

Azad are you sure you will get enough thrust with that combo...  As per thrust calculator that combo should yield around 700 gms of thrust...  Do give a thought on increasing the kv of the motor ...
All the best

AUW has not been calculated yet... only after that i'll finalise motor

Aluminium pipe is a good SPAD idea..
CF is stronger than aluminium pipe though..
Construction will restart next saturday evening...

I wan to achieve something like this...
Pics taken from here
http://www.rcgroups.com/forums/showthread.php?t=2194226 (http://www.rcgroups.com/forums/showthread.php?t=2194226)

Where do we get this aluminum channel?

u can get it in hardware store

i have already made this type of plane but in tractor configuration.flies well

some more pics of the boom attachment please....

@topale sorry to say that this plane is no more.i lost it when flying .it gavenose dive.btw i have that bottom piece.give me a minute

No worries...

BTW... I enquired about that aluminium railing...they sell mimimum 12 feet and nothing less than that...

no  no .last time i bought 2meter alluminium channel at rs40

After rummaging through our store room I found a ~2 foot peice which I think will be enough...
I tried sticking it to the fuse using SR 998 but the joint is appearing very fragile... What should I do?

Srinivas...youcl could drill holes and use m3 bolts and washers to secure the frame... Don't overtighten though

Trial with thermocol was good enough
After exchanging pms with lot of forum menbers, I made a thermocol wing which is light weight...
The present wing is of 1000 mm wingspan and 200mm chord....
covered with old dhoti of grandfather...
Its spar is hardwood beading 20mm...
extra spar is remaining on one side...
I'll chop that off after the wing dries completely...
Also I'm unhappy with the dhoti not sticking properly to the wing where it has overlapped several times...

I would like to thank shobhit sir for teaching me how to hand sand thermocol...
If he permits me I'll share his detailed pm over here...

here are some pics...

Can't see the aerofoil properly.

pour fevicol on the dhoti .and then spread it on that to thin layer.after drying it will harden ur airfoil.if u have hair dryer the blow it over the glue to dry.itwill hardly take 5 minutes to dry

the mistake I did was using lot of water...
Now I'll directly pour fevicol over it and try...

I cant feel the hardness of the wing right now...
If that trick doesn't work out, I'll use computer paper or tissue paper...

Here are the pms sent by shobit sir to me...
sharing this in public interest...

pm no. 1

Dear Friend,
Well all you need is to take a wood block of maybe 3 inches width and about 12 inches long.  Say .5 in thick.  Make three such Blocks.  DO NOT use plywood or ply board as it will hurt your hand and fingers with the sharp edges of wood which are there.

Now stick sand paper of 120, 100 and 60 grit to these blocks of wood.  Use the sandpaper which comes on cloth strips of about 4 inch width.

Now cut your sheets of thermocol of the required size.  Make sure the wing sides have come out exactly same in size.

Now make the max camber line on both top and bottom surfaces.  If its a flat bottom one then it is needed only on the upper surface.

Next make place for the Training edge and the Leading edge on the thermocol for the wing.  I use a 10 mm sheet balsa for the LE and a 6mm sheet balsa for the TE.  generally the sizes are 10 x 10 mm and 6 x 20 mm for the TE.

Sand the TE as required in a wedge form.  Fix the LE to the place on the foam.

Now sand the entire wing by keeping the thermocol on a table taking care to leave the place thich enough for you to fix the TE and also make sure that you shape the LE as you sand the wing using a 60 grit sand paper.  DO not file to the exact size with this paper as it is very rough and tends to breast the thermocol at times.

Use 100 and 120 grit paper to smoothen the wing surfaces......

After smoothening the wings add the TE to its place.

Now use a knife and cut grooves for the spars.  I have used hard wood spars and also used balsa spars.  Make the grooves on the top and bottom surfaces and put spars on both top and bottom surfaces.

For making the wing dehideral use a a 6 mm plywood piece or a 6 mm hard wood beeding as the centerpiece.  make use it is right through the thickness of the wing thermocol and is at least 6 inches outwards from the centre into each wing.

Now once all this is done.  I cover the centre section with a glass fibre cloth and epoxy.... about one foot of the centre section on top and bottom of the wings.  This gives great strength to the wing.

Now you can cover the wing with paper OR masking tape and later use vinyl sheet for various colours..... or paint the paper using fevicryl colours....

You can similarly make ur aerofoils and fix them to the wing.  Cut out the place for the servo and fix it there.

Best wishes....
Shobhit

pm no. 2

Well...... good show..  I do not fix the spar earlier as probably because my wings are bigger i.e. the minimum span I have made in 3.75 feet and have been made of at least one inch thick sheet of foam.  ANyway will try fixing the spar earlier if needed the next time.  Also I prefer to use fevocol for all my general work and I use the fast setting epoxy only for the dehidral angles or places which need to be fixed in a few minutes.

ok... now for your answers.....

Wing tips.... ok.  If you feel that you are going to bang the glider far too often then you may use Balsa wood wing tips.  OR else... just cover it with computer paper ad fevicol....  Use a thinned fevicol (use water for thinning) to paste a wet computer paper where you want to give extra strength.  While it is wet rub the thinned fevicol all over the paper and let it dry....  

You may use computer paper to cover the entire wing for added strength. Fix it the way I have written above and the wing becomes very strong.  But make sure that your spars are sufficient to give the strength required to the wing.  

I generally use masking tape and then vinyl sheet to cover my wings.  But off late have made an aerobatic model where the wing is just covered with paper and nothing else (a 4 feet span symmetrical cambered wing).

Do not for get to paint your model with fevicryl colours.....

Happy building your model.

Shobhit




Thank you so much sir for your guidance... :hatsoff: :) :salute:

 :goodjob:

Tommorrow I'll continue work on this as there is a bundh called by SFI and PDSU

This covering was not at all stiff...
Its also adding a lot of weight....
Removed this covering....

I tried heat shrinking packaging tape ( brwon colour)
Its not shrinking due to heat.... :)

wing completed.... ;D

if u are using normal thermocol there is another methord that u completely wet news paper wrapit around air foil neatly then give fevico0l coating inside and out side

what is the methord u are using to shrink the masking tape

The tape is not shrinking...
I tried with hairdryer which has a small heating coil...
it blows hot air...

it may not shrink suddenly .u try to blow hot air for some more duration

ok

Present weight of wing is 125 grams...

 please wait 5minutes i wll post my wings photo

whats length and breadth of ur wing.weight is fair

I have alrady stated before...
Telling again...
Its 1 metre wingspan and little less than 20 cm chord ie 8 inch chord
Did you build one like that?

her is the wing that i made out of hd foam got from lucknow

yes my wing span is 1meter by length and 18 cm by breadth.

No spar?
I guess that will be asking for trouble...
This way of covering is time saving...
But for scale modelling this is not good...especially the ugly colour...

What configuration are you planning..pusher or puller?
have you planned fuse?

here is another photo

That a lot of dihedral...
It might stall...

yes but i have already flew with this wing it climbs good.i think (notsure) its climb angle is 40degree something

i am planning to make it a puller with 1000kv motor and 10 inch prop,with 1000mah 3 cell battery.and for fuse i will b using alluminium channel.

as i m a biginner every time i made a plane i just crashed .so i thought if i decrease diedral i will get more stability even without remote.i have alredy tested glide.it just glides straight covers almost 30feet if thrown from 15 ft height .hope it will fly after fitting the motor

Topalle . get book covering clear plastic film from stationary shop.It is strong and will shrink also.
another option is gelatin paper, it also shrinks well , but very thin.

@Rajesh did you sand the wing or used Hot wire cutter.

sanded the wing

awesome work then.

i build a similar plane named flyer 1. have a look

https://www.youtube.com/user/priyanshz (https://www.youtube.com/user/priyanshz)

http://www.youtube.com/watch?v=gDjlvUEZmpk#ws (http://www.youtube.com/watch?v=gDjlvUEZmpk#ws)

Progress...

I don't have much experice with foam...
someone please suggest a method of making control surfaces...

Well... to all the learned aeromodellers out here...... 

DIHEDRAL does not make the wing stall more or make it unstable.... in fact DIHERRAL is given to the wing to make it more stable....... 
  Please read about this on the net and then use it to your advantage

Somebody recognizes this?

EDIT:picture is not getting uploaded
EDIT 2: will get the completed picture by tomorrow