RC India

Inspired by Sanjay Rai, we started the build on this....

http://www.rcindia.org/electric-planes/pilot-%28ok-model-co-%29-akromaster-in-corro-and-electric/msg227435/#msg227435

AKRO2 Correx + Depron build blog by Allan & Deepak.

Started 14th Sep2015. finished 13th August 2016…

Sanjay inspired us; he probably churned out 8 to 10 models in between.. 


On wing construction;


Depron Wing ; Spar; Hard Balsa 10mm thick 30mm narrowing down to 16mm
Wing panels in 3mm Depron weighed 73 grams for pair
Covered in packaging tape the weight for pair was; 99 grams.
The wing without servos, ailerons, tips and mounting ply panels weighed in at 275Grams ( ie. Including ; Depron covered in tape and scrim, Spar, leading and trailing edge in balsa)

Correx Wing; Spar; Hard Balsa 12mm thick (approx ½ inch)  x  4” wide sheets of balsa were used to cut the spars ; 2 pcs ; 69cm long x 38mm wide at the centre joint (Root)  narrowing down to 25mm at the tip to give it dihedral ( In order to make the Correx bend easier at wing tip this should not be more than 20mm!!!)
If you put the flutes lengthwise, the correx will flatten on the spar. So instead of an aerofoil, you will get a triangle… In other words the span should be 90degrees to the flute / parallel to the chord/  or the flute should run from front of the wing to back not left to right along the length (Span) (Length of wing is wing span and width is  wing chord.)
Wing panels left and right out of 4mm Correx weighed in at; 160 grams each
The spar joint with 1/8th ply at centre weighed 100 Grams. This would come out approx 160 x 2 + 100 + 20 grams servos + 45 Grams ailerons + 30 grams Correx centre brace and adhesive + 10grams  trim tapes = 525 Grams predicted
Looking at above weights, Allan’s Cap 232 wing with a similar span constructed out of Balsa covered with Orafilm with servos and wheels came it 392 Grams.

We decide to enlarge the chord of ailerons from 2.2cms on the Matsumoto’s scaled plan to 4 cms.
For this the ailerons were cut 1.5cms extra for insertion into the top and bottom sheets of the trailing edges.
In other words 5.5cms wide x 64cms long Correx strip with flutes going spanwise

Sanjays Original Model; "Originally designed as a Balsa Model for 25 size engines, he has adapted it to corro. Plans from on Outerzone.co.uk
Sanjay's
Brief Specs: Fuselage - 990 mm  39""
                  Span - 1360 mm      54''
                  Wing Area  - 27 dm2
                  Weight - 1500 to 1600 g
                  Channels - 4
                   Engine - 25"                  
                  
D & A AKRO2 Brief Specs;
Fuselage; 1000 mm / 1 Mt  (just under 40 inches)
Weight - 1530 g
 Channels - 4
Engine - OS Motor; OMA-3820-960  
Prop 12 x 6E (as per motor chart should be 12.6V 3 cell Lipo 40A ESC should be 504Watts and give 2.4Kg thrust)
If it doesnt go like a Bazooka..I will be changing the prop to 13 x 8E  so it draws 56Amps / 706Watts and give a 2.9Kg thrust.
ESC fitted is Emax Simon K ;60Amp
                  
Lipo 3Cell;  Zippy Compact 25C 3Cell 3700mah;280G with Xt plug               

Covered by packaging tape and decals of Solar trim.
Powered by OS Electric Motor from Sharma Model Aero;

Weight without Lipo; 1.53Kg


Wing Area in sq ft; Span (Distance in inches divided by 144 from wing tip to wing tip)               
               
Akro Master Wing Span; 27 x 2= 54inches               
Mean Chord; 9.5inches                
Wing Area; 54 x 9.5in =  513sq inches               
Wing Area in Sq Ft= 513 / 144 = 3.56sqft               
         

1.53Kg + .28Kg = 1.81Kg x 2.205= 3.99Pounds     ( Wt in Ounces; Wt in Kg x 2.205 x 16 )   

3.99Pounds  x 16= Wt in Ounces; 63.86 Oz               
                  
Wing Loading; oz per sq ft ; 63.86 divided by 3.56= 17.94 ounces per sq ft

Allan has built a similar plane in Balsa which has a similar wing loading and it flies a dream Lets see how this flies..

Wing construction...

More;

Very nice!  {:)} {:)}

Good luck for the maiden  :thumbsup:

Amazing! All the best!

Thank you Sanj and Girish
Deepak

Very good build sir best luck for maiden  :thumbsup: :thumbsup: waiting for video

Thanks Gaurang. Been waiting for a decent weekend. Weather here has been so unpredictable past few days. Was raining and windy today lets hope we get a break tomorrow......