If Carling designed an LAA aircraft?

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Re: If Carling designed an LAA aircraft?

Postby ColinC » Wed Aug 31, 2016 8:00 pm

Hi,

My comment regarding incompatabilty was in respect of currency for licencing, nothing else. A group A Shadow becomes a microlight if it is registered as SSDR and the hours only count on a microlight licence.

Regards,

Colin
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Re: If Carling designed an LAA aircraft?

Postby 4535jacks » Thu Sep 01, 2016 10:56 pm

I have been mulling over this some more and started to sketch a concept design with the following:

Single seat
40hp
Parasol
12ft spar per wing
12 ft longerons (longest length Aircraft Spruce sell on their website)
Wingloading 10kgm-2
Stall 40mph
Wing constructed of tube spar and crack cut ribs
Fuselage made of riveted angle 6061 T6.

I quickly realised that I was drawing and specifying the Texas Parasol! Sadly further research showed that the wing on the parasol could fail at 2g at MTOW! Oh well.

Having researched several construction techniques, I think that an aluminium ladder wing with tube spars and bent aluminium ribs (like airdrome airplanes) and a riveted aluminium angle fuselage (like the Texas parasol and belite) is the way to go for a lightweight and strong structure that is easy to build. Furthermore if I were to design something like this, I would try to get the length of materials as close to a whole foot as possible and not above 12ft maximum. For example try and get the chord length so the length of the top rib is 5ft rather that 4.6ft. This mean less wastage of materials and so lower cost. This setup favours a hi-wing design where wing struts at the centre of the spar significantly reduce the size of the spar and reduces deflection at the wing tips due to bending.
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Re: If Carling designed an LAA aircraft?

Postby Ian Melville » Fri Sep 02, 2016 8:36 am

Where do you get the 12 foot max from? The shipping companies won't ship more than 8 foot by air.

I needed 9 foot extrusions, and sourced them in the UK at an inflated price. Even then the max they could supply was 10 foot IIRC.

Not that it matters as a good design can overcome this.
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Re: If Carling designed an LAA aircraft?

Postby 4535jacks » Fri Sep 02, 2016 9:28 am

Ian,

I took that from the Aircraft Spruce Website as that is the maximum you can select so I assumed that was the longest they supplied.

I was looking at 3/4x3/4x1/8 6061 T6 angle on Aircraft Spruce and LAS it appears to be only £1+VAT per foot and so could be a very cheaper way of building a fuselage.

Gary
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Re: If Carling designed an LAA aircraft?

Postby ColinC » Fri Sep 02, 2016 7:46 pm

Hi,

Just measured a package under my bench that came from Aircraft Spruce which is 10ft long. I have had 12ft baulks of spruce delivered by carrier from a source within the UK which was the longest I could get sent by carrier.

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Colin
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Re: If Carling designed an LAA aircraft?

Postby 4535jacks » Fri Sep 02, 2016 8:54 pm

The point I was trying to make is that a 'carling' design should consider things like the units we buy materials in and what can be delivered to make it easier and cheaper to source materials.
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Re: If Carling designed an LAA aircraft?

Postby ColinC » Fri Sep 02, 2016 9:57 pm

Hi,

Totally agree, also a modular approach to construction has many benefits, not least the space needed to build it.

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Re: If Carling designed an LAA aircraft?

Postby Ian Melville » Sat Sep 03, 2016 6:49 am

Like Colin totally agree that any design should consider commonly available materials.

I've not brought direct from ACS in the US, but Wicks have an 8' limit, carrier cited as the reason. It does depend on what service you are willing to pay for but FedX and UPS both have international limits of 108" but do have some freight options allowing 119", other dimensions also need to be considered. Allowance would need to be made for any protective packaging reducing those effective lengths. Within the UK there should not be much of an issue as it is rarely sent by air. Having said that TW Metals have a max extrusion length of 10', the default cut by the manufacture.
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Re: If Carling designed an LAA aircraft?

Postby Bill McCarthy » Wed Sep 07, 2016 10:39 am

Many years ago, in the PFA magazine, someone had a problem with the supply of spruce to the correct grade and length. There was a suggestion that makers of high quality wooden ladders had the material - it was straight grained, satisfied the moisture content limits, was cheaper. After all, they have the safety of the product at heart just as we do in our builds.

On the subject of wood construction of plans built permit aircraft - again from a contributor to the PFA mag. A very apt safety consideration when building, is NEVER to finish a joint prep on a belt or disc sander as this fills the end grain with very fine dust, thereby substantially reducing the joint strength when its glued together.
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Re: If Carling designed an LAA aircraft?

Postby neilld » Wed Sep 07, 2016 10:47 am

Went to the rally last week-end to get some inspiration/ideas for this concept. Unfortunately most (all?) available designs appear to focus on appearance (traditional, sleek, and in one case outrageous) or out and out peformance.
I could see no attempt on a design for manufacture and/or functional approach.
The latest mag featuring the Davis DA-2A at least shows an attempt at DFM.
The recently reported OX vehicle( http://www.bbc.co.uk/news/business-37285399 ) shows what can be done in the automotive world when someone applies a bit of lateral thinking to functional design with the focus on ease of manufacture and cost. It may not win any beauty contests but it provides a low cost entry path to utility vehicles.
What we need is an Aero OX.
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Re: If Carling designed an LAA aircraft?

Postby 4535jacks » Mon Sep 12, 2016 8:23 am

Bill McCarthy wrote:Many years ago, in the PFA magazine, someone had a problem with the supply of spruce to the correct grade and length. There was a suggestion that makers of high quality wooden ladders had the material - it was straight grained, satisfied the moisture content limits, was cheaper. After all, they have the safety of the product at heart just as we do in our builds.

On the subject of wood construction of plans built permit aircraft - again from a contributor to the PFA mag. A very apt safety consideration when building, is NEVER to finish a joint prep on a belt or disc sander as this fills the end grain with very fine dust, thereby substantially reducing the joint strength when its glued together.


I alway cleans all wood joints with a damp cloth before gluing and apply the glue while the joint is still damp. Another LAA member recommended this after conducting some strength tests and found the joints that were damp when gluing were the strongest. The assumption is that the osmosis effect of the grain on the water creates a localised reduction in pressure which sucks more glue into the joint.

I have no concerns preparing a surface with a power file before gluing but would generally use some coarse sand paper or permagrit to rough the surface up a bit prior to cleaning with a damp cloth.
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Re: If Carling designed an LAA aircraft?

Postby ColinC » Tue Sep 13, 2016 10:46 pm

Hi,

That seems counter intuitive. I would expect glue to penetrate dry fibres more readily than wet.

I recall an old woodworker's trick of wetting wood to raise the grain prior to sanding, but that is irrelevant for gluing.

Stick to the manufacturer's recommedations.

I have recently become a convert to West Epoxy. The unfilled glue penetrates deep into the component's fibres and seems pretty foolproof

Regards,

Colin
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Re: If Carling designed an LAA aircraft?

Postby Ian Melville » Tue Sep 13, 2016 11:23 pm

Hi Colin, I have heard the same tip in model aircraft circles as well. Not seen any strong evidence to support theory, but I have had my own examples of joint failure in models.
The theory is that the initial application of glue is wicked into the dry wood, leaving a joint without sufficient glue. Modellers talk about double gluing. i.e. apply some glue to surfaces and let it wick in for a few minutes, then apply more and assemble joint. Wetting the surfaces sounds like another way to ensure there is sufficient glue in the fibres and in the joint. Surfaces still need to be a close mate.
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Re: If Carling designed an LAA aircraft?

Postby Brian Hope » Wed Sep 14, 2016 6:44 am

Gary, your concerns over 12ft lengths are not really necessary. 6082-T6 (formerly HE30) has been widely used by microlight builders and is readily available here in the UK in tube and extruded form.
Like 6061-T6 is not an aviation alloy, it is a high grade industrial grade that happens to have the appropriate qualities. 6061-T6 can also be sourced here and in Europe, although not as readily and not in all sizes.
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Re: If Carling designed an LAA aircraft?

Postby Landsurfer » Mon Jun 26, 2017 10:22 pm

Wood fuselage, metal structured or composite wings....?

Plagiarise a current wooden fuselage with metal structured or composite flying surfaces.
A FRED and VP2 that actually had some stress figures that made sense.
VP2 fuselage with a parasol wing, side by side FRED ????

Lets not re-invent the wheel, lets develop structures we have knowledge of.
Wooden fuselages and hot wire cut flying surface cores are not rocket science.
Proper home build stuff.

So ... an Evans VP1 fuselage, stab, fin and under carriage, with a parasol / high wing mainplane .....
VW 1600 twin port engine base.


Yes, a single seater ... Motorcycle of the Air .....
David Whiteside.
Hold my reins please, while i get down off my high horse !!!!
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