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AmarHV

Hi guys!,
I'm wanting to start building a plane. It will probably be pretty big, and have jet engines. I am going to do it in phases - most likely design, exterior, interior, cockpit, wings, engine,final stuff, CASA certification (I live in AU). I've done design and was wondering what materials to use for the exterior. I want it to have a pressure thingy so I can go up high in it. Where do I get them from? How expensive are they? And what material actually is it?

Thanks,
Amar
 

Dana

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A jet aircraft, particularly with pressurization, is a huge (and expensive) project that few amateurs have attempted, and fewer have completed.

-Dana
 
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AmarHV

I guess the pressure thing's not necessary. I'm mainly just wondering what material you make the fuselage out of and how you connect it together so that it doesn't fall apart when flying!
 
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AmarHV

Sorry, for 'Where do I get them from? How expensive are they? And what material actually is it?' I meant the exterior materials.
 

flyvulcan

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Messages
525
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Hi Amar,

I am a fellow Aussie but I also speak HBA lingo so I will translate what a number of our very experienced contributors have just said.

"The design and certification of any aircraft is an extremely major undertaking, both in terms of time and money. Historic and current precedents indicate that a certificated jet is likely to cost between $50m and $1,000m to develop through certification and into production. Assuming the seed capital is available to develop a proof of concept aircraft (let's assume around $10m for this phase), it is likely to be an absolute minimum of 2 years before it's first flight. Now assuming you obtain the additional funding required to certificate and commercialize the product (a further $40m to $990m), you are also likely to be looking at a minimum of 2 or 3 years and likely much longer after the first flight to reach the point where you commence deliveries and start generating a cash flow.
We are not trying to dissuade you from pursuing your dream as we would all like to own and fly one of these aircraft, but we would suggest you set your expectations a little lower to start with."

I hope that helps.

Cheers,

Dave
 
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AmarHV

I thought that certifying it with CASA was necessary. Since I'm not building it with a kit is it still so that I don't have to get it certified? Thanks.
 
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AmarHV

Hey Amar.

Roughly a billion US$. That's no typo, 1,000,000,000 US$. At least according to Eclipse, who were the last to do so succesfully.

Good luck!
Is that for the exterior materials or for certification?
 

Dana

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Amar, many of us (including myself) tend to get somewhat flippant with these kinds of questions, which we've seen many times before. The full answer is that aircraft design is not simply a matter of "what material to use for the exterior", "how to connect it all together", and "where do I get a pressure thingy". There is a reason why aeronautical engineering is a minimum four year degree program, covering advanced mathematics, structural analysis, aerodynamics, etc. An aircraft design is an integrated whole, requiring knowledge of aerodynamic loads, and understanding of how they're reacted by the structure. Pressurized aircraft go to a whole other level of complexity, as the changing loads from pressurization / depressurization can lead to metal fatigue (google the story of the De Havilland Comet).

To answer your specific questions, the exterior (which is the structure to a large extent) can be either aluminum or composites (fiberglass, kevlar, or carbon fiber), "connected together" by bolts, rivets, and/or adhesives. Pressurization is generally provided by bleed air from the jet engine's compressor stage, in conjunction with a relief valve (the "pressure thingy"?) to limit the internal pressure.

The first stage in aircraft design is to define the mission: How far, how fast, how high, how many passengers, etc. Everything else follows from there.

-Dana

But, Officer, a broadsword is hardly a concealed weapon!
 

autoreply

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Is that for the exterior materials or for certification?
All in one.

The only realistic thing you're looking at (unless you're a billionaire or a 100+millionaire) is the BD5J (which is still extremely expensive) or the Columban Cri-Cri with a jet engine and yes, both are kits.

Designing it isn't realistic, unless you're willing to put down a couple thousand hours to do so. See the "books" section for some great tips, but brace for some serious study ;-)
 

flyvulcan

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Messages
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Hi Amar,

I think you have thrown us all a bit by using the term "certification". I certainly took it to mean that you wanted to undertake "type certification" to allow you to sell completed aircraft commercially. Your more recent posts imply that you have used the term "certification" as an alternative for "Certificate of Airworthiness". If this is the case, yes, a CofA would be issued for your aircraft, either by CASA or one of their designated authorities (either within the SAAA or the RAA) under the provisions of the Experimental rules to permit you to build a one-off. Have a look at the SAAA and RAA websites for an explanation of the rules where they are summarised in plain english, as well as having links to the regulations themselves.

Also, have a look at this to see what has been done in Australia under the experimental rules.

Cheers,

Dave
 
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AmarHV

What would be the LARGEST kit that you can buy, even if it uses propellers?
 
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AmarHV

Thanks. That looks good. I'll look into it when its not night! :zzz:
 
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AmarHV

I can't find that plane? Is it the Gweduck amphibian? Or from Comp Air? Cause' they don't look like kits.
 
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