Flying wing 54"-- with vortex generators

-
This is a build log for a 54" flying wing with a blended fuselage 



Made out of Styrofoam and hotwired

Wing Span -  54"
Airfoil - MH 64
Root chord - 14"
Tip chord - 7"

The wings were hotwired out of styrofoam based on a MH 64 airfoil.

The spar was a strip of 1X3 carbon fiber glued in a shallow groove on the top and bottom surface of the wing. The two strips of CF act like a I beam with the foam in between, and being very strong in tension, makes a very rigid wing.

There was a central section 6.5" wide fuselage, which was blended with the wings. This would help by having more space for power train & electronics


 The CFs extended into the central section , which gave more rigidity and strength and intregrated the wings and fuselage better

The LE was covered with very thin fiber glass to reinforce it against dents

A view of the wings and fuselage joined together.. note the space being cut for electronics and battery.. . this would latter on be enlarged to cover nearly the whole length of the fuse
A view of the airfoil of the wing. It also give you an idea of how the CF spars have been placed and also the way the wings and the fuselage have been integrated..  like a blended wing


Another view of the blended fuselage ... from the rear

The wing and fuselage covered with paper.  It adds good amount of  rigidity and stiffness, is cheap and lends itself well to repairs, and is light.. a cheaper alternative to balsa sheet / fiber glass covering
To do this I paint a white glue thinned with water (40:60), over the surface  and then cover it with newspaper which is moistened with water. The thinned white glue adheres very well with the foam and paper, and as the moistened paper dries, it shrinks, and in the process the wrinkles disappears and most importantly the whole surface is taunt and under tension, giving enormous rigidity.
It takes a bit of practice to get it right, but once you are able to do it correctly, it is a very good covering .. just make sure that the glue and paper dies slowly and evenly across the surface, otherwise it might wrap due to uneven tension when shrinking

You can also see the servo slots cut out and the bottom keel which protects the lower fuselage while landing.

The Ailerons are full span, made out of 3mm balsa strips.. 0.5" at root and 1.5" at tip. The differential helps in overcoming the lack of twist in the wing (the wing was hotwired without any twist dialed in)


The wing after painting and electronics and power train installed..... note the vortex generators on the outer wings.. the vortex generators are a big help in delaying tip stalls

A flight video  of the wing is there in the link
https://youtu.be/IQu_I1ho7Zc

Comments

Post a Comment

Popular posts from this blog

Flipper - Plank flying wing SAL

-
Image
 This is a Plank flying wing for SAL or bungee The dimensions are  Span = 875mm, Root cord = 260mm, Tip cord = 160mm, sweep = 60mm. 20mm constant cord full length elevons The wing is hotwired out of EPP and then laminated with thin iron-on laminating film. The airfoil is PW51 7% thick at the root and PW51 7.5% thick at the tip. It has a 1.5 degree washout and a 45mm dihedral at the tips.  It has one 2mmCF spar glued to the bottom positioned at 40% cord. There is also a spar on the top surface biased to the rear to avoid elevon reversal. Two 9g servos are positioned vertically into slots cut on the top of the wing. The position of the servos are driven by the thickness of the wing at that part and distance from CG. The full length elevon is a tapered 3mm balsa with fiberglass lamination. ....Note I had to increase the elevon cord at the tips by 12mmto improve the control response (after the first flight trials) The fuselage is a 3mm CF rod glued onto the bottom of the wing...
Read more

Angor-Rot & Hot-Rod hotliner RC plane

-
Image
 Fast, hotliner design These two are built for speed, and unlike a 3 surface (wing , tailplane and rudder) design, they are wings (delta). The thought was having the max wing area for a given wt and strength and with the least friction/profile drag, and of course ease of construction. (ignoring  difference in Induced drag). Construction is composite, foam, glass fibre, carbon fibre and vacuum bagged,  resulting  in a very strong lightweight structure for its wt. Airfoil is PW 51, with a 1.5 degree washout at the tips. Small wing tips are added to draw out the tip vortex. The LE is reinforced with CF. The wings tips and the centre section of the underbelly has some CF  reinforcements built in. It has 2 layers CF tow of different lengths acting as spar. The paint pattern has been painted directly onto the skin and then vacuum bagged. The control surface hinges are live hinges built into the glass fibre skin. The servos and push-rods are embedded with the wing. All...
Read more

WitchCraft

-
Image
DESIGN This design explores the region between a plank and a swept wing flying wing, and to try and get the best of both worlds to whatever extent possible.... The major balancing acts were being efficient across a large speed range, good C l /C d , less twist, and maintaining good flight characteristics. PLAN & DIMENSIONS A span of 1200mm was chosen to keep it a one-piece plane.  - Sweep is a very moderate 13 degrees measured at LE, and even lesser when measured at 1/4 AC line. - - Aspect ratio =- 6.3... (adequate wing loading with the set span of 1200mm span) - Taper ratio= 0.65 and Twist - (-)1 degree..... (close to elliptical lift distribution, less induced drag, while maintaining decent Re and flow characteristics at the tips, good stall characteristics) - Airfoil is PW51.. (good cl/cd, adequate +ve cm, and minimum trim losses).  - A central tailfin is chosen over wing tip fins.... (due the the less moment arm and the issues arising out of a badly designed wing tip ta...
Read more