correction regarding specification need help to build a plane from scratch
 

Hi

thanks to everyone that replied.In my excitement in finding this forum. i made a mistake regarding the egg its just 59 g im sorry !!! (700g is dozen) ( you guys are right i can't find an ostrich egg). from scratch means not using ready made plane kits. I had to do the plan (blue print) by my self.

I am a first year and first semeseter aeroengineering uni students and we have been asked to build a plane from scratch. The aim is the plane has to fly and should take 700grams egg in it. I am new to this so and I feel completely out of element here. I have done the research on the net but only brings out full plane kits.

Can anyone help me


I been told that they is software were I can enter the specfication about the wings spane and fulegage weight and it will show me how the plane will fly or go flat.

please please some one help me with this



how to go

RE: need help to build a plane from scratch
 

Hey,

What do u mean by building from scratch? Do you have to design the whole plane yourself or can you go off plans?

Heres a website that calculates wing loading.
http://www.csd.net/~cgadd/eflight/calcs_wingload.htm

I would recommend a .40 to .60 size. You can go bigger but it will just cost more.
All up weight including your payload (the egg) should be about 3 kg for .40 size and 4.5kg for .60 size.
Wingspan of about 1.6m to 1.8m. 2m max.

Because you need an aircraft that can lift a lot of weight, i would recommend the following:

Flat bottom airfoil for high lift. You would also need about 2 degrees down thrust because of the high lift.
2 degrees wing washout. So that the inboard portion of the wing stalls first.
Straight, non tapered wing. Easier/quicker to build.
High wing, with no diherdal, or about 2 degrees, no more or otherwise it will be to stable.
Wing mounted to fuselage by dowel and rubberbands.
Conventional undercarriage (tail dragger), lighter, easier and stronger than convectional
Big wing surface area to get the required wing loading. You would want a wing loading of about 15 - 20oz/sq.ft.
Try and put the fuel tank as close to the CoG so that the CoG doesnt move as much when fuel is burnt
You would want a big prop diameter with small pitch. Because of the light wing loading, the plane will fly slow, so if you have too much pitch, it will just be inefficient.
Have a fuel tank of about 300ml (12 oz.) Any bigger will just make it heavier. 300ml will give you about 10 minutes of flight time.


Dont worry about trying to make a very high aspect ratio wing as it will be hard to make a long wing strong enough. The drag reduction from the high aspect ratio will be lost with the increase in weight to make the longer wing strong.

Hope this helps, be free to ask any more questions.
Cheers

RE: need help to build a plane from scratch
 

Does it need to be a powered and controlled plane (RC) or does it just need to fly (glider)? One is obviously much more complicated than the other.

And you guys have some BIG eggs down there (700g). I was thinking chicken, but you must be talking ostrich.

RE: need help to build a plane from scratch
 

Exactly what I was thinking.. That's a 24 ounce egg.

Check out a litle program called WinFoil for the airfoil design
http://www.winfoil.com/overview.htm

RE: need help to build a plane from scratch
 

Building a plane from scratch is a lot different from designing a plane from scratch. To most of us "Scratch Build" just means it was a set of plans and not a pre-gathered box of the needed parts in a kit. Get a set of plans for a Telemaster or Sig Kadet and you're gold.

Are there design limits? Size, weight, engine, length of runway? 95% of .40 engine size planes with enough power and wing area will lift an egg.

Do you also have to build the engine, actuators and transmitter/receiver? Now there's a challenge.

RE: need help to build a plane from scratch
 

700 gram egg??? does the plane weight equal 700 grams and it needs to carry an egg? 700 grams is approx 24 ounces right? Thats one big egg..(Ostrich maybe??) (hmmm didnd't see the other posts.. sorry)

If yoiu need to design the plane.. rather than build from plans.. lots of info for that on the web. Let us know.
Mike