Flying wing scratch

[viper1990]

Yep, another scratch build. Many of my scratch built planes failed, but so far only this , my f-15 and my glider flown



Specifications
Length: 30cm
Wing span: 120cm
Weight: ~500grams fully loaded
Motor: setup 1:900kv 11x prop (gentle)
: setup 2: 3550kv 6x prop (pretty fast but no verticals)
Wing thickness: 3cm @ 30% of chord.


I build this plane with depron ribs and many sataysticks as spars and sandwiched the skeleton with (um..whats this plastic thing called? see picture) Love this material.

This plane is very very very very durable. It went into flat spin about 3times, crashed nose first, and i got it flying again in a minute. Its pretty impossible to destory this plane unless i full throttle nose dived it .

Flight statistic:
First throw i got the CG right this time, and it went bouncing in the air. I tired with different CG. if its nose heavy it bounces, if its tail heavy it bounces and force the plane to do loops.

I never experience flying wing before and i must say they are very very sensitive to elevator. a little too much up elevator the plane will stall and bounce will take a few seconds to recover.

Went into flat spins as i do aerobatics (really annoying and frightening). Oh and belive it or not, there is this one flat spin, the plane was spiraling down a height of 40meters it flew into a large tree ,knifed edge pass the Y-shaped branches and emerge from the other side untouched , I was really really lucky,last moment the plane flare and come to a nice landing . My friends were laughing non-stop.

Overall:
Sustained Very little or even no damage to the plane after 2-3 flatspin crashes (so far ) I love this material.

Fun plane to fly, Flying wing planes have a funny feeling flying chararistic from Trainer or delta planes.

Though i just need some help in some areas like... ,how do i stop getting a flatspin? Larger winglet?

[Babylon5]

Hi, flat spin not so bad. My delta flat spin many times and land like a heli.
.....heh! heh! heh! just kidding. The winglet if of the correct size and c.g position can reduce the tendecies to flat spin.

You may want to try to experiment and increase the the winglet size for starter.

[Sunstorm]

It's called coroplast. Man, you beat me to it! You built a DAZI first!

When budget allows, use a 1600 with a 6-8 incher on 3s.

What's the weight? When I build my DAZI I wanna fly with you man.

[viper1990]

Completed my winglet ..just took me about 10mins to cut and superglued it on. I'll fly it tomorrow and see how it responds! Green winglet previous size , Purple winglet was the newly added)

[viper1990]

It's called coroplast. Man, you beat me to it! You built a DAZI first!

When budget allows, use a 1600 with a 6-8 incher on 3s.

What's the weight? When I build my DAZI I wanna fly with you man.

Haha,didn't know this type of planes is call a DAZI,Btw whats the difference of a ZAGI and a DAZI , they both look alike don't they?

Hum, the weight.., if empty my best guess would be 150grams max.
If fully loaded it will be..

Motor 68grams
Esc 27grams
2 servos 20grams
wiring 30grams
prop ~20grams
batt ~ 80grams
reciver ~30grams
Tapes all over the plane ~ 10grams
+ the empty plane itself 150grams

TOTAL: ~435grams

Btw, i'm running on 2s,its pretty fast and sensitive. I wonder what will 3s be like! ZOOM!

Ya don't mind meeting up to fly our dazi, just that..., i only got 1 battery pack of 2s, fly for 15mins+ have to go home don't have field charger. haha.normally which field u fly your planes?

[Sunstorm]

Punggol area.... but can go Woodlands if you fly there...
It's ok.

ZAGI is sold by this online company called Trick RC. It is made of EPP foam, which is bendable and strong.

DAZI is some guy decided to fold a ZAGI like shape with coroplast. It is unbreakable, as you have already experienced.

The other flying wings are just variants of this kind of flying wing. Except that they may come in normal foam, and are bigger/smaller.

[viper1990]

Haha, i either fly below my house or jurong west field, but mostly below my house cause its nearer.

Oh btw, nice mugi u built! saw it on your blog. I got this feeling that mugis have less tendancy to stall and bounce lesser then dazis cause of the longer delta shaped wing.

[Blackite207]

Viper,
Some pointers to note. Winglets reducevortex turbalance created at the wingtips and hept with the yaw tendancies. try the following:- extend the winglet below the wing by about 2cm. move the CG foward about 1cm to 2cm. Should help with your flat spins.
Cheers!

[joe yap]

Coroplast is almost unbreakable. But the amount of distortion it receives after bad landings and crashes can also render it un-airworthy. EPP wings however bounce back to shape better, as long as they are not covered with thick coverings. I paid a lot more for the original Zagi many years back, but it seems to last forever, even we used them for serious slope combat. I fown my first Zagi for 5 years before selling it away . Still in good conditions and pleasant to fly. My second model is still with me since I got it 3 years ago. They have already paid for themselves.

[viper1990]

Enlarged winglet:
Fly it at 7am this morning Never encounter any flatspins anymore ,yay, i can slow down rapidly,mini aerobatics ,stall without encountering any flatspins. Yep,i'll extend the winglet below the wing 1-2cm more and try flying my plane tomorrow again see how it goes!


By the way joeyap, If coroplast is so durable, why model airplanes aren't made up of those materials? parts like wings or underneath the fuselage for belly landings or even the whole plane itself , I know its heavier then foam or balsa..but..i don't mind adding some weight for more strength,Just a thought!

I haven seen any coroplast cessna or coroplast for EDF jets yet! that will be pretty cool and durable.

[joe yap]

Enlarged winglet:
Fly it at 7am this morning Never encounter any flatspins anymore ,yay, i can slow down rapidly,mini aerobatics ,stall without encountering any flatspins. Yep,i'll extend the winglet below the wing 1-2cm more and try flying my plane tomorrow again see how it goes!

By the way joeyap, If coroplast is so durable, why model airplanes aren't made up of those materials? parts like wings or underneath the fuselage for belly landings or even the whole plane itself , I know its heavier then foam or balsa..but..i don't mind adding some weight for more strength,Just a thought!

I haven seen any coroplast cessna or coroplast for EDF jets yet! that will be pretty cool and durable.

Durable? I'll say it's only crash resistant. Once subjected to UV rays of the sun, coroplast will start to break down by itself over a period of time. For my experience, my coroplast surfaces of my EPP gliders started to crack like biscuits after 2 years of storage and flyings. Like I said before, coroplast material my not break during landing or crashing impact, but the permanent deformation can distort the plane structure and compromise the flying characteristics.

I see some coroplast flying wings did well in their first season at Bedok Reservoir slope, but are hardly flyable in the next.

Again, you are just looking at material strength alone. A well design aircraft structure should not just only have strength alone. Structural stiffness also plays an important part, so that stress are shared around the structure so that no single structure has to bear all the load by itself at all time. Coroplast itself has very little stiffness and a practical wing need to have it fully wrapped around in order to achieve this. The end result is a very heavy wing. My TG-3 glider's coroplast tail is already warped after cutting it out from a large sheet. I stuffed some CF rods the flutes and only managed to straighten it a little. 2 years later, the CF rods torn themselves free from the coroplast surfaces.

Oh! I almost forgot. UV rays from the sun can also warp your coroplast material even without any crash landings. In long run, you'll see a lot of frustrations that your coroplast planes are almost unflyable after a while. So what do you still think that coroplast is so durable? Maybe this also answer to your question on whay kit manufacturer seldom produce Coroplast models.

I still remember in the early 90's, there was an American company which produces coroplast models which they called it 'Aircore'. Needless to say, they are hardly heard of these days.

Last but not least, I find that Coroplast planes are downright ugly, but that it just me. They still have a place, and at least they are good for some experimental projects that you are not sure how they fly, and don't want to spend too much time and cash building one.

[joe yap]

BTW, I was exactly like you in my school days. I tried to save cash by using cheap and readily available materials to build my planes. But it did not take me long to realise my room was beginning to pile up with ugly looking unflyable or damaged plane. I made some quick mental calculations and found out that I'd spend so much money buying raw materials and building junks that yielded very little successes.

I began to learn to go for proper materials like balsa and build quality models that fly well, look good and last long. Although I spent more, the successes yield are much much more than my foamies junkies. Now, I mainly use foams for wing cores and as building board. Coroplast are only good enough to be a cutting board for my iron-on films.

I hope you'll see the light that I did. You don't need to re-invent the wheels anymore.

[viper1990]

Hum, my bad, guessed i'm overrated the strength of coroplast. Thought that it was a good material from the begainning till you mentioned warping and deformation from UV from the sun....

Every material sure do have their pros and cons. like deporn is light but crack on impact.

geez, that means my wing won't last me for long, thats quite sad. Its fun to fly it. I should build a foamy or balsa DAZI all along, haha. But i can say that coroplast is actually a good material for begainner as they can crash (hope no wire come loose or faulty electronics) pick up and fly again.

Anyway thanks for your advices, haha, learnt something new about coroplast! Btw, this is my first time using coroplast to scratch built so i know nuts about it. The last few times i use coroplast was using it as my class notice board haha...

[Sunstorm]

Well different materials have different uses, and are suitable for different timescales, I guess.

Anyway it's just part of the hobby, part of your journey. Enjoy flying your wing while it lasts!

[Sunstorm]

Haha, i either fly below my house or jurong west field, but mostly below my house cause its nearer.

Oh btw, nice mugi u built! saw it on your blog. I got this feeling that mugis have less tendancy to stall and bounce lesser then dazis cause of the longer delta shaped wing.

Oh yeah, the first time I maidened it, it nearly crashed into a lamppost, some guys's car at PFW, and a jogger. However it was sufficient to prove to me that the thing flies, and flies reasonably well. No stall, no bounce.

The scolding I got after that was enough to put me off flying that flying triangle for a while.