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Please help with info if you can on scratch building

Posted: Wed Nov 04, 2009 1:05 pm
by Explorer
Guys I have been looking for an entry level plane for some time such as bush baby , cheeta and similar. Then I started thinking about scratch building and added up the costs and now it really looks like a viable option. However I have some questions but before I put them to you let me share what my thoughts are.

I would like to build a airframe very similar to the bush baby in construction and looks but would like to make the fuzz slightly wider and the wingspan two four foot longer for power I would like to use a 582. So basically its a simple plane and motor combination.

Now for the questions.

Do I need to have a aeronautical engineer approve the design on plan?
Will CAA issue me with a build number and what details do I need to provide them with ?
Will I have to provide CAA with a set of plans ?
If I do obtain a build number and begin building are there any CAA inspectors in the Cape Town area to assist me?
Are there any min requirements on tubing for the fuzz ? I plan to use 19mm tubing with a wall thickness of 1.6mm

These are by far not all the questions I need answers to but they are the deal breakers.

I will appreciate all responses.

Re: Please help with info if you can on scratch building

Posted: Wed Nov 04, 2009 1:29 pm
by Morph
The best is too talk to the EAA guys, Tailspin is on this forum and heads up a chapter up in Gauteng, but perhaps he knows the CT boys. They have all the inspectors, engineers you might need.

Being a new model you will have to perform all the structural tests for CAA like testing the wing loading etc, which could lead to destruction of the wing for example, so it could turn out to be a really costly exercise. The mountain of paperwork you are going to have to go through puts Mount Everest to shame.

You also want to keep weight down to a minimum, the Bush Baby uses 10mm and 15mm mild steel tubing (.9mm thickness). Kitfoxes use Chrome molly, which allows it to be thinner, but hellishly expensive.

Why not build from plans, as opposed to designing your own?

We have a guy at Morning Star who is scratch building an aerobatic aircraft similar to a 2/3 scale Extra 300s. His frame is Chrome Moly and his fuse/wings are Carbon Fibre. However he has 25 years experience in building planes and has a Carbon Fibre manufacturing business.

Re: Please help with info if you can on scratch building

Posted: Wed Nov 04, 2009 1:46 pm
by mikeinPE
Its a huge bite you want to take on if you want to design & then build. Just my 2 cents worth, why not buy a plan & build your first project that way. Thereafter if the bug really bites you design & build your own.

Im scratchbuilding a Zodiac 650 & its going at a slow pace. Zenith also sells plans for the 750 which sounds like something you might be interested in. Have a look: http://www.zenithair.com.

The Bearhawk is another excellent plane you can build off plans.

Enjoy your research!!

Re: Please help with info if you can on scratch building

Posted: Wed Nov 04, 2009 1:48 pm
by Explorer
Thanks Morph

I thought the BB was built from 20mm steel tubing . So I guess that 15mm and 10mm will be perfect and perhaps bring the cost down even more.
Yes I know of the aircraft been built in CT. Lets say I have perhaps a very similar set of skills and knowledge as the mentioned builder.

Are there any plans available for tube built airframes which are similar to the BB and KF. If so I would go that route as I have heard from the builder of the aerobatic aircraft about destructive tests on wings and that puts me off ( I was hoping that was because the aircraft was intended for +- 10 G's )

Thanks for the info, I have requested the same from the CAA certification dept a few days ago but have had no response could this be because I should have been speaking to the guys at the EAA.

Thanks again

Re: Please help with info if you can on scratch building

Posted: Wed Nov 04, 2009 2:09 pm
by KFA
Hi Explorer,
I think you called me the other day in connection with this. You will firsly have get plans for an approved design. You should be able to get this from CAA. Should you want to register your own design you will have to show compliance with one of the international standards like FAR 23 or JAR VLA etc. After you have satisfied the engineering department at CAA you then have to start the building your proof of concept. If you decide to go the tubular route you then have to be a lisenced aircraft welder to weld the airframe. An AP is only allowed to do repair work and not allowed to weld a new airframe or modify an existing one. Scratchbuild from plans would be your best option and I would suggest wood or allu.
Regards
Stefan

Re: Please help with info if you can on scratch building

Posted: Fri Nov 06, 2009 12:20 pm
by Explorer
Hi Stefan

It must have been someone else who called you. But thanks for all this info. Well I guess then it seems as though if I dont get plans for the right airframe then I will have to wait another 10 years to afford to buy a ready to fly aircraft.

Guys I have looked at the bearhawk and the CH 705 and they are awsome aircraft only thing it that the engine requirements are to big. This project needs to fly with a 582 or Jabiru motor. So is there anything that there are plans for which will fly on 65hp and is easy and quick to build. ( exept the raven )

Thanks again

Re: Please help with info if you can on scratch building

Posted: Fri Nov 06, 2009 12:29 pm
by Morph
http://www.ultralightnews.com/plansbuye ... index.html

Super Koala from Fisher is a great aerie, quite a few flying

Re: Please help with info if you can on scratch building

Posted: Fri Nov 06, 2009 12:38 pm
by Morph

Re: Please help with info if you can on scratch building

Posted: Mon Nov 09, 2009 9:58 am
by Tailspin
Hi All

To scratch build something is not in every mans blood.
Here are some answers for you.
Do I need to have a aeronautical engineer approve the design on plan?
Yes if you are building the first or the only of a type - or at least you need to prove on paper that it will do the Job.
My suggestion would be to purchase a set of plans of an aircraft that has flown and has been tested.
But if you have a design and you are willing to go through the (**) at CAA - KNOCK yourself out (^^) !!!!
Will CAA issue me with a build number and what details do I need to provide them with ?
CAA will issue a build number the papers you need to fill in are available on the web

Will I have to provide CAA with a set of plans ?
Not really but you will have to prove to them that you are not building a go-cart with a huge engine that will kill you - and that it will actually fly

If I do obtain a build number and begin building are there any CAA inspectors in the Cape Town area to assist me?
There are many AP's and people around that can help you out in that department - You are welcome to contact me if you need some info or need to be pointed in the right direction. Morph and the guys have given some answers that are very informative

Are there any min requirements on tubing for the fuzz ? I plan to use 19mm tubing with a wall thickness of 1.6mm
There are certain G-Loads that you will have to test your aircraft to if it is to be the first of a type.


STRONGS ##

Re: Please help with info if you can on scratch building

Posted: Mon Nov 09, 2009 10:41 am
by Explorer
Thanks for the info Tailspin this has put the feather back in the hat.

Morph I realy like the super Koala ( almost bought one a while back for a steel but someone stole it before me ) I cant seem to find anyware to order the plans or even price of the plans. Does anyone in SA perhaps have the plans . I know there are many of these flying or have flown for many years. One of these on a 582 will be perfect.

Thanks again

Re: Please help with info if you can on scratch building

Posted: Mon Nov 09, 2009 10:44 am
by Morph

Re: Please help with info if you can on scratch building

Posted: Thu Nov 12, 2009 2:04 pm
by Explorer
Thanks for all the info guys I have just emailed the guys at Fisher to request further info from them.

Regards

Re: Please help with info if you can on scratch building

Posted: Wed Nov 18, 2009 11:13 am
by Explorer
Hey guys I have not had any response from Fisher do they still exist??


Cheers

Re: Please help with info if you can on scratch building

Posted: Wed Nov 18, 2009 12:10 pm
by Explorer
What are your thoughts on the SB2 by Steve Boshoff
?

Re: Please help with info if you can on scratch building

Posted: Wed Nov 18, 2009 1:15 pm
by Tailspin
Explorer wrote:What are your thoughts on the SB2 by Steve Boshoff
?
It is a very nice Aerie.
Make sure you use the correct engine but did see it fly and it did perform very well.
Worth looking into. ##