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  #1  
Old 04-01-2007, 10:13 AM
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Default Aluminium gyro?

I have been looking at alternatives to a welded steel tube structure for a JT-9 trainer that i want to build.
the use of glass+epoxy looks very complicated
can anyone assist me with help opinios re building it from aluminium angle and skin like the Zenith Stol 701
i've got a complete set of plans
thanx
leon
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  #2  
Old 04-02-2007, 04:19 AM
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I would use what the plans call for. I didn't know he sold complete plans.
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  #3  
Old 04-02-2007, 11:25 AM
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Default Plans

That's the problem.
Jukka never did anything more than the original concept drawings.
And these are not really PLAns as such.
That is why i need expert help,
or where i can get such design help

leon
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  #4  
Old 04-03-2007, 09:26 AM
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Hi Leon

I'm building a tractor out of riveted aluminum angle, have been on it about a year, because it is based on a fixed wing fuselage called the "Texas Parasol" and I am making mods to the fuselage as I build it.

Have just about finished the fuselage itself and am now ready to start on the rotor mast assembly and then the tail feathers and finally a new main landing gear, it will suprise you how heavy aluminum angle is, at present setting on the old aluminum gear without mast assembly and tail, it weights 97 pounds and it will be covered in fabric. By the way, riveting is not as easy as it seems!!!!!!!!

Tony
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  #5  
Old 04-03-2007, 10:39 AM
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Doug Riley Doug Riley is offline
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Aluminum has a slightly better strength-to-weight ratio than 4130 N steel (the stuff used in aircraft tubing). The difference is not nearly as great as some people seem to think, though. Unless an aluminum structure can be stuck together with joints that are as weight-efficient as welding, the aluminum structure with strength X will weigh MORE than the same strength structure made of welded steel tubing. That's certainly going to be true if the aluminum structure is covered with fabric, which adds weight but no strength.

Cessna 150-style construction, using thin sheet-metal ribs and stringers and lots of little aluminum rivets, is weight-efficient. The same construction put together with the kind of adhesives used on good rotorblades will be even more efficient.

A structure of extruded aluminum angle with relatively few rivets won't be nearly as good, especially if it doesn't have a load-bearing skin. It'll be heavy for its strength. It'll fly, though, just as our heavy and non-structural fiberglass pods fly.
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  #6  
Old 04-03-2007, 10:44 AM
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Hello,

I heard that the British authorities do not allow aluminium masts because of frequent breaking. While steel will deform plastically, appearantly aluminium alloys tend to crack. The mast being under repetitive strain would be especially vulnerable I guess.

Kai.
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  #7  
Old 04-03-2007, 01:17 PM
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Default jt-9

my thoughts were to build the fuselage from .025 skin with 0.25 bent angle, not extruded.
the mast will be 4130 airfoil shaped steel, mounted with some kind of rubber bushing
i want to use a factory like Air command rotorhead and Dragon wing blades
leon
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  #8  
Old 04-03-2007, 01:23 PM
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That certainly could work and be reasonably light. Chris Heinz is a good designer.

Be careful about the aerodynamic effects of a pod built this way. It will have flat sides and will therefore have quite an effect. The tail surfaces must be able to counter these effects at all speeds and flight angles -- including slips, vertical spins and so on.
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  #9  
Old 04-06-2007, 12:55 PM
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Default materials

i have been doing research on the net about different materials
if you look at the figures for 6063-t6 an 6061-t6 they are very similar with the 6061 being about 28% stronger.
would it be correct to upgrade a 6063 angle by 28%(thickness) to get the same as 6061. if that are not available
lastly what are the effects of a sharp angle compared with a round bend as for 3/4 x 3/4 angle
thanx
leon
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  #10  
Old 04-06-2007, 02:57 PM
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Why use 6063 in place of 6061? My prices show that 6061 T6 is much cheaper, as there is more demand for it. And if you are going to go thicker to gain the same strength, you are adding that much more $$$ and weight. I don't see the reasoning.
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  #11  
Old 04-07-2007, 03:13 AM
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Question 6063-t6

Like i said in South Africa 6061-t6 are not obtainable.
I will have to import from USA- Very Expensive
6063-t6 are available though.
But are it safe to use in airctaft ????
leon
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  #12  
Old 04-07-2007, 10:30 AM
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Default 6063 Aluminum

6063 aluminum has less tensile and sheer strength than 6061 and it has tremendously less fatigue life. It is an architectural grade of aluminum and has good resistance to corrosion but I would not even think of using it in load bearing structures where there are bending loads involved.

Try drilling holes in 6063---they will not even be perfectly round and the material is very grainy.
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  #13  
Old 04-07-2007, 10:44 AM
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Bolt holes will wallow out in no time.
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  #14  
Old 04-16-2007, 12:54 PM
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Default surface

thanx for the info
I don't understand what doug means by the flat sides being a problem
most tractors i've seen tries to make the vertical surface as big as possible especially towards the tail
just look at the cierva's for instance
i thought this will it more stable
ofcourse i understand that a nice big horisontal stab are also needed
regards
leon
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  #15  
Old 04-17-2007, 05:11 PM
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Deon,

Look at my other post regarding VHS tapes that are on sale. This ia a reputable dealer with some good tapes.

Jim
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