DELTA DYKE -Coro Delta
This is the build of a large coro delta
It is made out of 3mm and 2mm coro..
Wing Span - 1200mm
Root Cord- 765mm
Tip Cord-250mm
Sweep -485mm
Dry weight - 1020gms
Motor ;3630 1100kv, 40 amps, 3S 2200mah,
2 x 12gms servos
CG -280mm from nose tip (at 15%)
With a total wing area of 609000 sq mm and a AUW of 1200 gms the wing loading is at 6.4 oz/sqfeet, which is in the region of slowflyers.. this combined with a not too small Reynolds number for the avg cord, translates to good stall characteristics.
It is quite a big aircraft. The underside is 3mm coro and the topside is 2mm coro.. The spar is a tapering XPS foam wrapped in fiberglass. This makes the spar very strong.. in fact this spar is the only load bearing structure in the whole aircraft.
For gluing coro to coro, fevicol SR (a rubber based solution) was used and epoxy was used for foam to foam or foam to coro or wood. The TE was also taped up after gluing.
The controls are through full length Elevons.. no rudder. The Elevons are made of balsa and foam sandwich and operated by 12gms servos
You can see the curvature of the wing to a airfoil shape... this is achieved by wrapping the top surface over the tapered spar. The spar height is 6% of cord at the root and 8% cord at the tip.
The lower tail fin, also acts as the rear skid, giving the aircraft its stance while on ground.... also being in the clean bottom surface it provides directional stability at high AoA when the top tail fin is blanked out by the wing
Top view.. you can also see the hatch for inserting the Rx..
The bottom view .. You can see the two hatches for the servos . The servos are attached to the main spar . Any strong attachment can be used.. I built a box out of foam, glued it to the spar. The servos were inserted into the slots and hot glued.
The motor is mounted on a "L" bracket glued onto a balsa block glued to the bottom skin and also to the wing spar (with epoxy) ..The esc is tucked into the wing.. the battery is mounted (velcro) on a foam block glued to the wooden bottom
A close-up of the leading edge.. The white surface is 3mm coro.. the top surface is 2 mm coro.. the LE has a overlap of the top surface by1.5 inch
The coro doubler on the nose bottom surface... the CF rods are odd lengths which were lying with me. They have been put, partially for some strength, and primarily to stop the zip ties from cutting through the coro when tightened
The undercarriage is a CF undercarriage which I had. It is fixed to the fuse (wooden block) with zip ties... this has proved to be a very simple & robust set up... I normally get 5/6 landings and touch&goes on a very rough field, before the zip ties give way (and prevent damage to other parts of the aircraft).. The greenish wire which can be seen is used to to loop around the battery, mounted on the top part.. this along with the velcro holds the battery securely in place
I use https://fwcg.3dzone.dk/ for calculating the CG of my wings and keep it at 15% . Fortunately the CG was spot-on in the first flight . Given the size, it was a rolling takeoff. I could take off at 70%, and very quickly had to throttle down. The aircraft climbs at 50% throttle and can hold altitude at 30%. Very stable. .. high AoA dues not induce nasty tip stalls, the aircraft oscillates on the roll axis, and drops its nose and comes out of the stall.. I sometimes trim it to fly in circles, entering a shallow bank with elevons and then holding it there. It flies with hands off with @ 30% throttle. This has also flown with a 1.2kg deadweight as payload
A flight video
https://www.youtube.com/watch?v=kbau_SH1_Jc&feature=youtu.be
Another video
https://www.youtube.com/watch?v=au5KSUfMVBs&feature=youtu.be
It is made out of 3mm and 2mm coro..
Wing Span - 1200mm
Root Cord- 765mm
Tip Cord-250mm
Sweep -485mm
Dry weight - 1020gms
Motor ;3630 1100kv, 40 amps, 3S 2200mah,
2 x 12gms servos
CG -280mm from nose tip (at 15%)
With a total wing area of 609000 sq mm and a AUW of 1200 gms the wing loading is at 6.4 oz/sqfeet, which is in the region of slowflyers.. this combined with a not too small Reynolds number for the avg cord, translates to good stall characteristics.
It is quite a big aircraft. The underside is 3mm coro and the topside is 2mm coro.. The spar is a tapering XPS foam wrapped in fiberglass. This makes the spar very strong.. in fact this spar is the only load bearing structure in the whole aircraft.
For gluing coro to coro, fevicol SR (a rubber based solution) was used and epoxy was used for foam to foam or foam to coro or wood. The TE was also taped up after gluing.
The controls are through full length Elevons.. no rudder. The Elevons are made of balsa and foam sandwich and operated by 12gms servos
The motor is mounted on a "L" bracket glued onto a balsa block glued to the bottom skin and also to the wing spar (with epoxy) ..The esc is tucked into the wing.. the battery is mounted (velcro) on a foam block glued to the wooden bottom
The undercarriage is a CF undercarriage which I had. It is fixed to the fuse (wooden block) with zip ties... this has proved to be a very simple & robust set up... I normally get 5/6 landings and touch&goes on a very rough field, before the zip ties give way (and prevent damage to other parts of the aircraft).. The greenish wire which can be seen is used to to loop around the battery, mounted on the top part.. this along with the velcro holds the battery securely in place
I use https://fwcg.3dzone.dk/ for calculating the CG of my wings and keep it at 15% . Fortunately the CG was spot-on in the first flight . Given the size, it was a rolling takeoff. I could take off at 70%, and very quickly had to throttle down. The aircraft climbs at 50% throttle and can hold altitude at 30%. Very stable. .. high AoA dues not induce nasty tip stalls, the aircraft oscillates on the roll axis, and drops its nose and comes out of the stall.. I sometimes trim it to fly in circles, entering a shallow bank with elevons and then holding it there. It flies with hands off with @ 30% throttle. This has also flown with a 1.2kg deadweight as payload
A flight video
https://www.youtube.com/watch?v=kbau_SH1_Jc&feature=youtu.be
Another video
https://www.youtube.com/watch?v=au5KSUfMVBs&feature=youtu.be
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