Singapore Poly Final Year Project scratchbuild planes

[viper1990]

Hi, ok this time i'm won't be posting stuffs of my scratchbuild planes but the 3 FYP groups i'm currently helping.

I've been very busy with school works, projects,my own scratch build planes and my comming exams. Been helping other people's plane more then my own, but nevertheless it is more fun because they have the school budget,can do more expensive stuffs


FYP groups i'm currently helping:
1) Global Hawk 5m wingspan
2) SkyBox (Build according to singapore's skyblade UAV)
3) Solar powered glider

Number 2 and 3 have sucessfully madien, Skybox at woodland flying field while the solar powered glider is flown at Singapore Poly. Global Hawk had a "Lack of thrust" problem, will be madiening soon in a couple of weeks time in december.

1) Specifications of Global Hawk:

Electronics:

6s thunderpower 5000mah
100A hobbywing esc
GS Inrunner BL Motor B44-65-04 2060kv
120mm Haoye EDF

Dimensions:

5meter wingspan
Wingloading 18oz/ft sq
Weight 8.5KG fully loaded

2) Specifications of SkyBox

Electronics:

9s 4000mah voltron battery , 3x 3s in series
Phoenix-85HV esc
GS Outrunner BL Motor C63-62 320KV
Spinning 15inch wooden prop as pusher

Dimensions:
3meter wingspan
Wingloading 22oz/ft sq
Weight 11.5KG fully loaded

Specifications of Solar Plane

Electronics:
2s 500mah battery (as backup power)
20 x 0.7Amp 8V solar flim 12gram each
Esc (forget the specs but should be 30amps)
Axi Outrunner spinning 11inch prop (Can't remember the kv)

Dimensions:
1.5 Meter Wingspan
Clark Y airfoil white foam
Wingloading 5.4oz/ft sq
15degree dihedral ( i think its abit too much, but the whole plane is very stable)
Weight 1KG fully loaded

[viper1990]

The Skybox is depron foam built around a plywood core with many many square carbon fibre rods holding the structure of the plane. 5 to 30min epoxy is use depends on which specific part of the plane. The Main fuselage holding the wing is heavily epoxied with 1/8 to 1/4 plywood. At some parts it got 1/2 thick to hold up the wing that weighs 3kg.

Wing is designed to have a whitefoam core, expoxied then laminated with balsa with a 2x carbon 5mm fibrerod running in parallel. The wing flexs 5-10degree up when we lift the whole plane while only holding the mid section of the wing. But it holds strong without signs of cracking.

The CG is then finally determined to be at 1/3 of wingchord. But at first the CG was at 1/2 wingchord. About 1kg of weight is placed infront to get the CG in place.

Wings can be disassemble and assemble by removing one at a time from each side of the fuselage. It's held tight by rubberbands (Many many of em) inside the fuselage.

Camera is mounted at the bottom of the SkyBox , with servo to control it's camera angle which makes it as realistic as the real UAV plane

[Cycross]

Viper1990, arguably you students are amateurs in building. But do yourselves a favour next time and get the preparation work all sorted out ahead of time.

It was not fun at leisure watching you folks do the setup for 1.5+hrs, and I am very sure you folks don't enjoy baking in the hot midday sun either.
I hope none of you got severe sunburns after that.

Any pic of model 2 in flight?

[romihensem]

hmmm

was there waiting for the maiden but unfortunately it never came by the time i went back. i think u guys took a good 4-5 hrs just to setup the plane. but 1 thing i notice bout the global hawk is the wings seems to be touching the runway. was wondering how u manage to taxi without damaging the wings???

[viper1990]

We hired a van to carry both planes to woodlands flying field from Singapore poly. It'll be awesome if we carried those on the MRT train....

And we took a long 1hour to set up both planes , by 2pm pushed both planes to the long runway in the middle of the field. GlobalHawk was unable to takeoff because lack of thrust, so back to the drawing board for those guys.

SkyBox front landing gear servo stripped and unable to control the steering as it was taxing towards the runway. Ground crew give the greenlight for taking it off even though it was damage. Snice we are all here at woodlands, must as well give it a try! The plane steered right and sometimes left on the few attempts, But on the thrid try, it went straight and off it goes!

SkyBox took off within 15meters of runway! I didn't expect it to lift up so soon as i thumbed the throttle all the way up

I made a 1minute 30second flight, Could have been more, but i'm not taking any risk here.... ,landed the plane as soon as i made few rounds around the field.

Celebrations and cheers were given as the plane landed and veered off into the grassy patch, if its were on the pavement, its massive 11.5kg momentum will need a very long runway to slow it from ~50km/h to a halt , tonight the team can sleep well... , 5months of hardwork have paid off for the SkyBox team. Now they are in the process of painting and putting on decals for display in Singapore Poly.


oh, and how could i forget about this video Enjoy...

http://www.youtube.com/watch?v=wMLjl3YKJU4

[viper1990]

Guys guys..., we took a very long time for serveral reasons. obviously we don't wanna stay under the baking sun, but we did anyway and all of us got sun burned the next day

I'm sorry that we took so long to set up the plane on that day. But please understand that they are all first timers in setting up planes at a flying field on that very day.Things went wrong the last minute such as the landing gear servo stripped,control surfaces tightens up. They were all double and triple checking every wires connections, control surfaces ,etc... , Who wants to lose a 6months of hardwork and a very expensive plane to a crash that happens in a fraction of a second.

Thanks for understanding!!! i don't mean to argue here .... just telling you guys in a friendly way

By the way,romihensem, the global hawk wing scrapped the ground because the ground near the road wasn't even. Once its at the runway both wingstips were 2-3cm apart from the ground. Even though it feels like hitting, when it's near rotation speed, the wings lifted up quite high ,around 30-40cm so no problem taxing and taking off (though it didn't takeoff properly yet)

[romihensem]

hmmm

Guys guys..., we took a very long time for serveral reasons. obviously we don't wanna stay under the baking sun, but we did anyway and all of us got sun burned the next day

I'm sorry that we took so long to set up the plane on that day. But please understand that they are all first timers in setting up planes at a flying field on that very day.Things went wrong the last minute such as the landing gear servo stripped,control surfaces tightens up. They were all double and triple checking every wires connections, control surfaces ,etc... , Who wants to lose a 6months of hardwork and a very expensive plane to a crash that happens in a fraction of a second.

Thanks for understanding!!! i don't mean to argue here .... just telling you guys in a friendly way

By the way,romihensem, the global hawk wing scrapped the ground because the ground near the road wasn't even. Once its at the runway both wingstips were 2-3cm apart from the ground. Even though it feels like hitting, when it's near rotation speed, the wings lifted up quite high ,around 30-40cm so no problem taxing and taking off (though it didn't takeoff properly yet)

no worries bro. no ones blaming u. its yr hard work guys. got to really admire u ppl for even taking the effort on the project. btw saw yr vids on youtube. but got ask a favour from u.... hope u do will post yr aerial view at woodlands on the net (if theres any...) help to preserve the field and to prevent further complications.... hehhehe

[romihensem]

hmmm

but got ask a favour from u.... hope u do will post yr aerial view at woodlands on the net (if theres any...) help to preserve the field and to prevent further complications.... hehhehe

corrections... gotta ask a favour from u... hope u will not post the aerial shots at woodlands....

[GLENDON]

corrections... gotta ask a favour from u... hope u will not post the aerial shots at woodlands....

haha no worries we did not took any aerial from woodland cus of the airbase beside it. My lecturer won't even allow us do that.

[romihensem]

hmmm

haha no worries we did not took any aerial from woodland cus of the airbase beside it. My lecturer won't even allow us do that.

good luck on the global hawk.... hope it goes smooth too...

[joe yap]

Good job, folks. Designing and building UAV this size by students is by no means an easy task. Keep it up.

BTW, you can explore increasing the efflux velocity besides increasing static thrust.

[GLENDON]

Good job, folks. Designing and building UAV this size by students is by no means an easy task. Keep it up.

BTW, you can explore increasing the efflux velocity besides increasing static thrust.

ya will take note. thats the global hawk i told u about lastime.

[viper1990]

Good job, folks. Designing and building UAV this size by students is by no means an easy task. Keep it up.

BTW, you can explore increasing the efflux velocity besides increasing static thrust.

After you said that i did a few researches regarding choosing the correct pitch speed for models.

I found out for rule of thumb, keep pitch speed at least 2.5x the stalling speed of a model. Stalling speed for Skybox is approx 30km/h (I got this number from calculations) Therefore pitch speed must be around 75km/h.

Right now the plane is running on a 15inch x 7 wooden prop on 320kv on 9s = 110km/h pitch speed (neglecting drag, engine losses, blah..blah..blah)
But, because we wanted the plane to be a STOL (short take off and landing) uav , we upsized the prop instead of changing the pitch.

The globalhawk on the other hand is running by ducted fan, so there will be lots of pitch speed and lesser static thrust. It actually run down half of the runway at woodlands just to get the plane to rotate slightly!!! After that we didn't actually attempt to maiden the global hawk cause we're afraid something wrong might happen. Right now we're gona get a bigger motor and different kv ,fit into the 120mm EDF to improve static thrust and more pitch speed , we are aimming for a ~2000kv motor on a 6s for the 120mm edf, if no other suggestions, we'll take the globalhawk down to woodlands in a few weeks time and give it a go again.

Btw, its quite shocking that i calculated the pitch speed for the 120mm edf to be 342km/h...,nevertheless we'll still give it a shot with that motor/edf combination, worst case senario the EDF blades tear up the tube ducting due to high rpm and plane come crashing towards the ground haha, joking

[chiadennis]

Hi Viper1990

Saw you guys last Saturday trying to maiden the 2 UAV, how was it?
Couldn't stay as it was get hot and we were all hungry.

[stranger]

hope you can make the smaller one quick.
haha nice video.