RC India

RC Models => Self-designed, DIY and College Projects => Topic started by: harsha on May 16, 2011, 08:44:09 PM

Title: scratch build foamie
Post by: harsha on May 16, 2011, 08:44:09 PM
hi friends,im trying to build a scratchbuilt plane,
im posting the pics,all your suggestions are welcome......
material used is high density thermocol
Title: Re: scratch build foamie
Post by: harsha on May 16, 2011, 08:47:50 PM
i think the model is not so good,but as a beginner im just trying to build my own model,the motor mount is sticked by using fevicol sh....
Title: Re: scratch build foamie
Post by: Samanth on May 16, 2011, 08:53:43 PM
you should be proud of yourself if your a beginner. :D
Its good only... :) Nice Job :thumbsup:

Important:
1)Use Epoxy (araldite) to fabricate the motor mount stick to the foam. Fevicol Sh wont be good at all. Trust me.
2)And what are the Dimensions and Weight of this model ?
3)What power system are you planning to use ?
Title: Re: scratch build foamie
Post by: harsha on May 16, 2011, 09:14:23 PM
thanq very much for your reply samanth

i will use araldite as you suggested for the motor mount
the weight of the model without the electronics is 280gms
the power system i have with me is 1500kv motor,tpro 9gservos,2s1p 1000mah battery,30amp esc

when i done a test on the plane using a 1047 and 8040 props it ie moving very fast and it had very good thrust with 1047 prop(as i hold the tail part with my hand),but when i used 8040 its is moving very slowly
u can check the motor properties here
Rotational Speed
2600 RPM/V
Free Load Current
2.0A
Max. Current
8A-20A
Input Voltage
6 - 22V
Max. Efficiency
98%
Weight
44.46g
Motor Dimensions (Diameter x Length)
27.8mm x 23.0mm
Shaft Diameter
3.00mm (Front and Back)
Speed contorller requiement
20A
Input Battery Types
NiCd/ Nimh/ Li-po Battery
Recommend Model
Airplane
Title: Re: scratch build foamie
Post by: Samanth on May 16, 2011, 09:23:23 PM
Hmm...using a 20A ESC for a 20A motor will generate quite some heat, just make sure you dont run it at 90-100% throttle for a long time.

I am not sure if this will work for high density thermocol, but you can try this -
sand the leading edges of the wing and nose using 320grit Sandpaper or Emory sheet. It will really really help and I have had excellent gliding performance with my models after sanding.
Title: Re: scratch build foamie
Post by: harsha on May 16, 2011, 09:50:09 PM
it works with this material,and i had done sanding with Emory paper of different grade,i used kfm2 airfoil,i have to test the flight at no throttle whether it glides or not,but still have 2 doubts  ........
1.the length of the plane is 96cms and the length of the wing is 1mts without dihedral,so can this wing will be able to create a good lift?
2.how to design the rudder and elevator????
Title: Re: scratch build foamie
Post by: sultan alam on May 17, 2011, 08:04:41 AM
@Harsha
 I think ur total weight with electronics part will be approximately 380 gm .That's good.
 U mentioned that ur length of ur wing is 1m but not mentioned  breath of it.
 plzz give the details of ur plane including actual weight with plan, will help us to solve ur problem.

And for rudder and elevator it is not easy to make it using thermocol.Use coro sheet .Cannot found?
Ok go to nearest cellphone card recharge shop and tell him to give a small advertising sheet of any telecom company.Really they print using coro sheet.
Plz refer the images.

For more details follow this thread
http://www.rcindia.org/self-designed-diy-and-college-projects/glidiator-my-first-trainer-build-log/
Title: Re: scratch build foamie
Post by: harsha on May 18, 2011, 02:11:12 PM
@sultan:thanq bhai,i used coro material for rudder and elevator,by the way the length of the wing is 1mt and chord of the wing is 27cms,im thinking to use kfm2 airfoil
Title: Re: scratch build foamie
Post by: sultan alam on May 18, 2011, 02:41:05 PM
Give ur wing aerofoil shape.And also mentain ur cg correctly.I have also made like one .The design is overall complete.
In 5 or 6 days i will post the pic
Ur wing size is sufficient for lift and remember to give aerofoil shape to it.
Title: Re: scratch build foamie
Post by: harsha on May 18, 2011, 02:49:56 PM
sure,i will update the progress soon :)
Title: Re: scratch build foamie
Post by: harsha on May 19, 2011, 06:53:24 PM
hi everyone,
some more pics,i made the wing with kfm2 airfoil,let me know if i made any mistake in making the wing
wing profile:
kfm2 airfoil(i used one thermocol sheet,cut down into two pieces,sandwiched them one on the other and sanded the trailing and leading edges)
1mt length
27cms chord
Title: Re: scratch build foamie
Post by: SunLikeStar on May 19, 2011, 07:08:35 PM
The step should be at 50% of the cord, the top layer of thermocol should cove only half the cord. Also you will need a sharper leading edge, sand both top and bottom surface equally.

Refer:
http://www.rcgroups.com/forums/attachment.php?attachmentid=3433154
Title: Re: scratch build foamie
Post by: harsha on May 19, 2011, 07:09:58 PM
my doubt is that im using a 1500kv motor with 8040 prop and 2s 1000mah lipo
but the plane is not moving at all when it is given 50percent throtle,it hardly moves when the throttle is given full,how to solve this problem and make it fly????
and where should be the c.g of this plane????
Title: Re: scratch build foamie
Post by: harsha on May 19, 2011, 07:14:15 PM
Quote from: SunLikeStar on May 19, 2011, 07:08:35 PM
The step should be at 50% of the cord, the top layer of thermocol should cove only half the cord. Also you will need a sharper leading edge, sand both top and bottom surface equally.

Refer:
http://www.rcgroups.com/forums/attachment.php?attachmentid=3433154
thanq,i will modify the wing now
Title: Re: scratch build foamie
Post by: SunLikeStar on May 19, 2011, 07:16:04 PM
What is your planes total weight?
Title: Re: scratch build foamie
Post by: harsha on May 19, 2011, 07:16:46 PM
i didnt measure yet but it will be not more than 480gms thats for sure
Title: Re: scratch build foamie
Post by: SunLikeStar on May 19, 2011, 07:21:51 PM
Then you should have enough power with this setup. Finish your wing and then post some picture of your completed plane.
Title: Re: scratch build foamie
Post by: rohitgupta322 on May 19, 2011, 07:22:05 PM
Have you put in the prop correctly? Like the "8X4" written on the prop should be facing outwards away from the plane.

C.G should be at a distance of 1/3rd the total chord length from the leading edge.
Title: Re: scratch build foamie
Post by: harsha on May 19, 2011, 07:39:06 PM
@sunlikestar:sure bro
@rohitgupta:ya the prop is facing outwards away from the plane
ya the c.g is little bit further like 1cm,i think this made it nose heavy,when i throw the plane it glides well,but when it is kept down and tested for the movement,its moving heavily...
Title: Re: scratch build foamie
Post by: ajith on May 19, 2011, 08:02:00 PM
harsha 
Try  sanding  the  front  part of  the wing  with  a  sand  paper    so that  it  gives  some  aerodynamic  shape 

may  be  like  this !!


seniors  suggest  Us.....         (I am  a Newbie too ..   :giggle:) 
Title: Re: scratch build foamie
Post by: harsha on May 19, 2011, 11:29:00 PM
i modified the wing here are the pics,let me know if there is any mistake,i will try to rebuild or change the wing
Title: Re: scratch build foamie
Post by: SunLikeStar on May 19, 2011, 11:59:24 PM
I doesn't look like KFm2 anymore but i'm sure it'll fly  :thumbsup:
Title: Re: scratch build foamie
Post by: rohitgupta322 on May 20, 2011, 09:25:44 AM
Since you have come this far, I thing you should finish it but coro would have been a much better substitute for this thermocole.
Title: Re: scratch build foamie
Post by: harsha on May 20, 2011, 11:23:29 AM
Quote from: rohitgupta322 on May 20, 2011, 09:25:44 AM
Since you have come this far, I thing you should finish it but coro would have been a much better substitute for this thermocole.
ya,but coro is comparatively heavy material so i used this material,instead od kfm2 airfoil can i take a flat wing????will it make the plane fly better???
Title: Re: scratch build foamie
Post by: SunLikeStar on May 20, 2011, 11:37:24 AM
I have a bigger concern, from the pictures it looks like your wing doesn't have a dihedral. Its an absolute necessity if you are a beginner.
Title: Re: scratch build foamie
Post by: rohitgupta322 on May 20, 2011, 12:15:48 PM
Coro is heavy when compared to thermocol but it is light enough to build planes. The advantage of using coro is that you can get a better aerofoil shape out of it and it is more rigid than thermocol.
Title: Re: scratch build foamie
Post by: harsha on May 20, 2011, 12:25:14 PM
@rohitgupta:thanq for the advice bro,i will try to buy some coro and builld the wing,but for now im confused about the electronics too,hope someone would help me.....
thanx in advance,
harsha
Title: Re: scratch build foamie
Post by: harsha on May 20, 2011, 04:57:15 PM
guys what should i do now,should i dump the plane and make a new one with less weight???
Title: Re: scratch build foamie
Post by: ajith on May 20, 2011, 09:38:49 PM
No .

Your plane  is  looking  fine ...      what they mean by  " Dihedral "  is   raising  the wings  edges  from both sides a bit  above  to the  level where the wing is attached to the fuse

This  gives  more Stability  as " We are  beginners  and  More stability  is  NEEDED  for  Our  Learning  Period "

If  You  are now thinking  to make  a  Dihedral wing  Just  take  two Cycle spokes   and  insert them into both ends of the wing (side's)  and  take  a thin  nylon  or  any strong thread and  tie  it  to both ends  of the spokes  and  tighten  slightly  till you  get a required dihedral Dont  Make  it  more tight ...  wing  may  break  at  center ...   Make sure  You  re-Enforce the places along where the spokes  are inserted  and  Mainly  at the center ....


Never Think that Your  (any Ones) models  are  not Fly-worthy ...!!        They just need  a little  modifications  :thumbsup:
Title: Re: scratch build foamie
Post by: harsha on May 20, 2011, 09:47:41 PM
thanq very much ajith,im just thinking to try tip dihedral wing,would build the wing and will post the pics... :) :thanks:
Title: Re: scratch build foamie
Post by: ajith on May 20, 2011, 09:56:11 PM
Some  specs  of  MY Plane... 
did  some  work  as  Bunked  collg  today    :giggle:

wing ; elevator ; Rudder      just placed  not  attached    8-)



Seniors  waiting  for  Your  Comments   :salute:    :headscratch:  Suggestions ...... 
Title: Re: scratch build foamie
Post by: harsha on May 20, 2011, 10:04:44 PM
beautiful work ajith,but i think the elevator should be parallel to the wing(seniors correct me if iam wrong)
Title: Re: scratch build foamie
Post by: rajathv8 on May 20, 2011, 11:09:24 PM
Harsha i think you need to upgrade to 3s 11.1v lipo. 2s may not provide sufficient power and it because of this tat it is not pulling.

http://desirehobbyrc.com/index.php?act=viewProd&productId=55

With 8x4 you can use 3s and it may take the weight. With 2s you may need a bigger prop.
Title: Re: scratch build foamie
Post by: harsha on May 21, 2011, 12:22:41 AM
[Admin Note] Unwanted "Quote" removed... use "Reply" instead... See usage guidelines : http://www.rcindia.org/rc-india-forum/forum-usage-tips/

so can i use a 1047 prop with a 2s battery instead of 8040???
i had tested with 1047 prop its pulling at 50 percent throttle,the esc is fine but the mortar is little bit hot
Title: Re: scratch build foamie
Post by: s2k on June 06, 2011, 04:03:11 PM
Quote from: harsha on May 16, 2011, 08:44:09 PM
material used is high density thermocol
where do you get this type of thermocol
Title: Re: scratch build foamie
Post by: rohitgupta322 on June 06, 2011, 04:19:52 PM
High density thermocol is normally available in Insulation/Refrigeration stores. But, I still feel that coro is easier to work with, unless u get extruded polystyrene a.k.a biofoam.
Title: Re: scratch build foamie
Post by: harsha on June 06, 2011, 05:14:53 PM
here i can get high density thermocol directly form thermocol factory,which is nearer to my house :) ;D ;D
Title: Re: scratch build foamie
Post by: s2k on June 08, 2011, 03:47:31 PM
Is it available at any stationary or some other shop?
Title: Re: scratch build foamie
Post by: s2k on June 08, 2011, 03:50:37 PM
Do you have any idea that how much a rc plane costs about? ;D
Title: Re: scratch build foamie
Post by: harsha on June 08, 2011, 04:15:01 PM
@ s2k:the one which is available in stationery shops is not a high density thermo col sheets,high density thermo col is something we get in fridge packing,electronic goods packing etc...and i think there are many websites,research for sometime in rc india and rc groups,i dont know much about the cost of a beginner plane  :)
Title: Re: scratch build foamie
Post by: rohitgupta322 on June 08, 2011, 08:42:01 PM
Quote from: s2k on June 08, 2011, 03:50:37 PM
Do you have any idea that how much a rc plane costs about? ;D

It is a very vague question, its like asking how much a car costs? Well it depends on what you want, the type of plane, what you already have at hand, etc.

The cheapest you could get to a complete ready to fly package with reusable parts will be around :Rs: 7-8k .

Spend some time and research the forum thoroughly. Most of the beginner's questions have already been discussed earlier.
Title: Re: scratch build foamie
Post by: KALYANPRODHAN on June 09, 2011, 12:17:02 AM
What is the dencity of your thermocol? Generally art quality thermocols are 4.5Kg/Cubic Meter and Delux quality are 6.5 Kg/Cubic Meter. High dencity thermocols start designated by dencity from 7 and dencity 20 is good/optimum for aeromodeling. Some people order Dencity 34 also. This is how they (dealer) specify the thermocol.

Generally Thermocols of dencity 20 sell price is 130 - 200Rs/Kg and you have to order at least 1 CuM. Despatch charges extra from Dealer's outlet. This is the scenario of Kolkata. What is your cost harsha? Can they produce fuselage patern & wing if provided with the dice or they make dice? Wastage will be less and simultaneously perfect shape with low cost will be available to us.

Actually I find the dealer in kolkata but not find the factory till now.

Thanks
Title: Re: scratch build foamie
Post by: VC on June 09, 2011, 12:24:33 AM
Kalyan, what is the highest density of thermocole available in Kolkata in retail and what are the prices?  I need some high density thermocole urgently.

Regards.
Title: Re: scratch build foamie
Post by: VinayakR on June 09, 2011, 12:54:11 AM
@VC : It costs  :Rs: 80 for 5mm sheet 65 * 95 cm and   :Rs:90  for 8 mm sheet 50 *80 cm in Pune

@ajith  : is it a blue baby ?, I am also building same of high density thermocol  it looks same like yours but it's of 28" only :) . this will be my first plane. will upload pic soon ..
Title: Re: scratch build foamie
Post by: Ranjit369 on June 09, 2011, 01:26:28 AM
Loooks like blue baby..Beautiful plane Ajith, dense thermocol are less expensive light weight at the price available locally. I have used it to build some of my scratch builts. here is the most recent one.Electrics need to be installed-
Title: Re: scratch build foamie
Post by: VinayakR on June 09, 2011, 12:14:33 PM
Here are some pics of my blue baby :)