Singapore Poly Final Year Project scratchbuild planes

[joe yap]

Viper,

You are calculating just the pitch speed, but for DF you should be looking at the efflux velocity. The pitch speed may be high, but a poorly designed exhaust duct can reduce the efflux velocity drastically. The actually thrust are produced only when the air exits the exhaust nozzle, not the fan.

[viper1990]

Viper,

You are calculating just the pitch speed, but for DF you should be looking at the efflux velocity. The pitch speed may be high, but a poorly designed exhaust duct can reduce the efflux velocity drastically. The actually thrust are produced only when the air exits the exhaust nozzle, not the fan.

Oh yes.... i forgot! The FSA thingy and the bernoulli theorem. Thanks for reminding. The FSA for the global hawk is standered 120% intake, 80% at exit. Don't worry about the exhuast duct. I asked them to keep it as smooth and clean as possible and the walls inside are strengthen with plastic bottles and transparent plastic.

By the way, i've posted the link to the video somewhere in the thread, those cannot find it its right here,i made it more eyecatching so people can find the link

****VIDEO OF THE SKYBOX OFFICIAL VIDEO****
------------------------------------------------------------------
***** http://www.youtube.com/watch?v=wMLjl3YKJU4*****
------------------------------------------------------------------

[viper1990]

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.

Haha, really sorry to keep you guys waiting. I've posted the video up , go take a look see!! it went fantastic , the CG was spot on, the control surfaces were like already trimmed for me... i didn't even need to trim it. , took off without the aid of the front landing gear...., the servo gear stripped. So the plane became a blind missile,hoping it zoom straight down the runway and yes it did!

[joe yap]

Oh yes.... i forgot! The FSA thingy and the bernoulli theorem. Thanks for reminding. The FSA for the global hawk is standered 120% intake, 80% at exit. Don't worry about the exhuast duct. I asked them to keep it as smooth and clean as possible and the walls inside are strengthen with plastic bottles and transparent plastic.

By the way, i've posted the link to the video somewhere in the thread, those cannot find it its right here,i made it more eyecatching so people can find the link

****VIDEO OF THE SKYBOX OFFICIAL VIDEO****
------------------------------------------------------------------
***** http://www.youtube.com/watch?v=wMLjl3YKJU4*****
------------------------------------------------------------------

120%? Way too much I think. If you are taking about the intake area at the widest part of the bellmouth lip, it should be fine. If not, than I think the excess mass flow into the throat will be spilled out of the inlet, causing a increase in drag, since the DF system cannot process the excessive massflow. Don't forget, you are acceleratiing air, not compressing it for combustion.

[viper1990]

120%? Way too much I think. If you are taking about the intake area at the widest part of the bellmouth lip, it should be fine. If not, than I think the excess mass flow into the throat will be spilled out of the inlet, causing a increase in drag, since the DF system cannot process the excessive massflow. Don't forget, you are acceleratiing air, not compressing it for combustion.

Yep, 120% at the widest part, the furtest out you can go at the lip. Just move in 2-3 cm and calculate the cross sectional area it'll stay at ~100%. I've drawn a picture to illustrate.

Note the cross sectional area expands once again as you go inwards, that is alright isn't it? so as long the intake is 100%

[Spooky]

Global Hawk

Hi Guys!

I wonder if anyone of you have considered employing the same concept as the U2 on you Global Hawk. That way your wings won't be scrapping the ground.

Cheers!

[MeePokMan]

Viper,

Cool project. Keep up the good work - I'm sure your subsequent projects would be make the UAV closer to the real Mccoy.

At 5m wing-span, I wonder if you have the largest RC plane in Singapore?

[pixeldixel]

Congratulations! very happy for you guys! great video btw.

[viper1990]

Hi Guys!

I wonder if anyone of you have considered employing the same concept as the U2 on you Global Hawk. That way your wings won't be scrapping the ground.

Cheers!

Great idea! Thought of that too, but i didn't let them know about it because the wing isn't really touching the ground..it only looks like it. But still, i might let them put wheels on the wing tips.

Viper,

Cool project. Keep up the good work - I'm sure your subsequent projects would be make the UAV closer to the real Mccoy.

At 5m wing-span, I wonder if you have the largest RC plane in Singapore?

Hmmmmm...umm...., errrr *scratch head..., Yeah might be! If you exclude the army's UAV planes, this might be the biggest rc plane in singapore owned by public

Congratulations! very happy for you guys! great video btw.

Thanks!! Global hawk video will be comming out next when i get it off the ground and flying!

[jansonfinn]

BTW, I have seen bigger planes than this but using gasoline engine lah in SG.

So he need change the statement to, biggest RC EP plane in SG excluding those used in RSAF

[Adrianli]

Sorry for being a bit kaypoh, did u guys approach any r/c clubs site to fly??? In the name of SP, flying at an "illegal" area and posting the video, not very nice leh.

There may be some repurcussions down the road.

[viper1990]

Nope didn't approach anyone. We don't want to go through so much trouble just to fly that thing for a mere 1minute 30seconds. All we wanted is to see the plane fly and land safely. Don't mean any harm or wad so ever trouble.

The purpose of the Video i created
1) Is part of the school project
2) Can be use for future reference ,motivation for the future students doing some UAV down the road
3) Have good memories of that very day
4) and share my experinces with you guys.

I didn't even thought that posting the video might cause trouble, if there is any reasons i should remove the video, i'll do it right away.

[jansonfinn]

Nope didn't approach anyone. We don't want to go through so much trouble just to fly that thing for a mere 1minute 30seconds. All we wanted is to see the plane fly and land safely. Don't mean any harm or wad so ever trouble.

The purpose of the Video i created
1) Is part of the school project
2) Can be use for future reference ,motivation for the future students doing some UAV down the road
3) Have good memories of that very day
4) and share my experinces with you guys.

I didn't even thought that posting the video might cause trouble, if there is any reasons i should remove the video, i'll do it right away.

Coz the main reason for not posting it on net is becoz people may mistaken that aerial view was taken while flying at that FF (Although some ex-SP students may recognise that as FC3 field), n since ur plane have the capability to take aerial videos, other might think otherwise, thus leading to security matters, especially towards SAB

[Adrianli]

I am not against u or anything. Just a frenly posting. Just wana let u know:

1) Cover ur own backside.

2) SAF CORE value number 6 : Do anything u want but dont get caught.

[Ghostfit]

Sorry for being a bit kaypoh, did u guys approach any r/c clubs site to fly??? In the name of SP, flying at an "illegal" area and posting the video, not very nice leh.

There may be some repurcussions down the road.

I agree with Adrian, ...but it's not so much the flying at an "illegal" area part that I would be concern about.

Have you guys got it covered in the event that you lose control of the model and it cause property damage, injuries or death ?

It one thing being hit by an GWS E-Starter type park flyer and a totally different thing should it happen with that 5m model.
I know, ...."It'll NEVER happen to you" ...I'll bet that joker who crashed his turbine Jet into the factory at Tuas also thought the same thing !

Please dun get me wrong ! ...I DO admire the creativity and perservence of you youngsters, and being able to put your Skybox in the air is commendable.
But do spare a thought for any eventualities and make sure you are covered. One mistake and it will put a blemish on your young lifes.

Sorry for my rant !