Build log : Lil Ripper modified (removable 2 piece airfoil wing)

Started by allthatido, June 26, 2012, 02:44:52 PM

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allthatido

Hi guys

I built a plane called Lil Ripper. It was designed by 3DMON as a full fuse but with flat plate wing fixed permanently to the fuse. Since I have a bike to take my planes to the airfield..I had to design a new wing which was removable for transportation.

So while I designed a removable system I thought why not try a airfoil wing to go with the full fuse. This was my first try at building one. Also this was the first time I tried to cover a plane all over by color tapes.

Please note I have already completed the plane. Attached is the pic of the completed plane.

Ankur

allthatido

The deatils are as follows :

Wingspan : 31 in
AUW : 500 grms
Motor : emax cf2822
Esc : 25 amps
Servos : 9g x 4
Lipo : 1000 mah
Prop : 10x4.7

You can search lil ripper on rcgroups for plans

rcpilotacro

cool, 2822 what KV ? 10x4.5sf will be good for 3d has good punch at low speed, however prop unloads fast at mod-high speeds
Gusty's Hangar and Introduction.

A Good pilot will practice until he gets it right,
A Great pilot will practice until he can't get it wrong.

allthatido

Hey Gusty Sir how are you ? Kv of the motor is 1200. I checked with a watt-meter..it was drawing 12 amps at half throttle with sufficient thrust.

I am still learning on axn..so no 3d for me as of now..built this plane just for the fun of building..Praddy will fly this and we will check how well the plane does aerobatics.

Regards
Ankur

vishalrao

Nice plane Ankur! What material did you use, especially for the wings?

allthatido

Hi Vishal thanks..a highly detailed build log will follow..hold your horses..will explain everything :)

vishalrao


allthatido

1) Got the templates generated and printed from www.worldofkrauss.com. Airfoil chosen was a flattened Clark y with root and tip chord as 9 and 6 inches resp. No of intermediate ribs was chosen as 5 which will give you a total of 7 ribs per wing.

2) The templates were traced on 5mm depron and cut with a hobby knife. A total of 14 ribs are there. Next the aileron portion of the ribs was cut from the main wing ribs. The length of the aileron on the tip rib is 6cms and on the root its 10 cms.

3) The wing profile was traced on 3mm depron and accordingly aileron portion of the rib was cut from the remaining ribs.

4) All the ribs were notched to provide clearance for carbon fiber rod and stuck to the 3mm depron as shown in the pic.

allthatido

5) A carbon fiber rod of 4mm was cut and glued at 30% of the chord length using foam safe CA and then was topped up by fiber tape. I did not cut any groove for the rod in the 3mm depron as it was too thin.

6) The leading edge of the 3mm depron was scored to ease bending. But before doing that you need to back up the other side by applying scotch tape on the other side. This prevents any cracks while you are bending. Be careful with the scoring..use a ruler to get straight scores or your wing will get an odd shape at the LE.

7)Cut the aileron portion of the wing and align the ribs with the main wing ribs. Then glue them.

8 ) The bending was the most difficult part of the build as it was my first time. I totally failed in my first attempt using hot water to ease bending. Also I would strongly recommend to use only foam safe CA and nothing else as glue. Slowly apply pressure on the sheet to bend it progressively. Apply CA on top of the ribs and bend the sheet. See pic for reference

allthatido

Btw this is a better close up of the completed plane. And accurate color reproduction.

vishalrao

Super! Really appreciate this detailed build log :) Bookmarked this thread. Thanks again!

BTW, where did you get 3mm depron? Want to try my hand with it to build a wing.

allthatido

I got 3mm depron from Dadar, Mumbai. You will have to check your local resources for availability at Mangalore.

vishalrao

OK thanks! Will check. It's called Depron only right? Is Styrofoam same as Depron?

allthatido

Yes depron is a closed cell Styrofoam. Its also called biofoam in India

vishalrao


allthatido

9) I used 1mm wood laminate to cut out a base for putting servos. Used dremel for it. Chk pic.the servo was installed and the wire routed to exit at the root face.

10) Now apply tape over the trailing edge of the upper surface of the wing and bend it to complete the wing. This closes the main wing body. When happy with outcome..apply CA and stick together. Trim and sand the edges till you are satisfied.

11) Now onto the ailerons ..in order to create a bevel..the lower sheet on which the ribs were glued was cut by 5mm as shown in pic...such that the ribs extended out at the front...see pic for clarification. The ribs were then re-cut to have a slanting edge as opposed to a straight one earlier. Then a depron sheet was then glued on the top. Edged trimmed and sanded thereafter.

12) The aileron is then closed by gluing another depron sheet as shown in pic.

allthatido

More pics for aileron construction.

VC

Very neat and precise build Old  young chap! You have taken a lot of pain and effort for this build. I wish you all the very best for the maiden and thereafter! :thumbsup:

Can't log into www.worldofkrauss.com, what exactly do they do?
Growing old is mandatory, growing up is optional!

allthatido

Ha ha VC thank you so much..Old and me..no way..in both age and experience..at the mentioned website you can study polar graphs of airfoils, compare them specify inputs like root and tip chord, no of ribs to generate an airfoil template for the wing.

I generated the template from the same website ( first pic)

Ankur

allthatido

13) Using a tape hinge attached the aileron to the wing. Fixed the servo horns and pushrod.

14) Covered the entire wing in color tapes. Bottom is full black and top yellow.

The wing came put to be 69 grms before covering and 75 after covering.

allthatido

15) Cut the elevator and rudder from the plans and covered in color tape.

16) Cut the fuselage side and top panels from the plan, covered in color tapes and glued together.

17) Added bulkheads in the fuse to add rigidity. (not from plan)

allthatido

18) Cut 2 pieces of 1mm wood laminate as shown in the pic for each wing. They will be glued to the root of the wings.

19) Cut a piece from 4 mm coro. This will to be used to hold wings wen joined. A carbon fiber rod through the flutes will provide stiffness Check pics for clarification.

20) The coro piece is glued as shown in the pic. It extends upto the first rib in both the wings.

21) The middle portion is then cut and the wood lamnates glued to the wings.

allthatido

Finished wing by gluing the wood laminates.

allthatido

22) Put the wings on the fuse as you would want them and then trace the wood laminate holes on the fuse. I have mine with some +ve angle.

23) Cut 4 pieces of wood laminates to provide rigidity to the depron sides.

24) Glue the laminates

25)Trace the coro piece on the fuse. This will be cut later. Pics will make the process clear.

KALYANPRODHAN

We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.