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Old Sep 25, 2012, 11:16 AM
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looks awesome rich!

should fly as good as it looks too
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Old Sep 25, 2012, 05:03 PM
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I certainly hope so. its built to scale, and I can't wait for it to arrive to try out.
this will definitely have to be video'd for the first flight attempt.
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Old Sep 26, 2012, 01:44 AM
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yeah i definately want to see that!!
do u mind if i ask how much you payed for it?
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Old Sep 26, 2012, 08:27 PM
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And from where did you get it...........??
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Old Sep 26, 2012, 11:46 PM
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where

got them from http://www.aviationproducts.de/e/home.html goto the scale models and there is a price list and pics of quite a few models.

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Originally Posted by britinoz View Post
And from where did you get it...........??
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Old Sep 26, 2012, 11:47 PM
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Price

412 euro shipped to the land down under.

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yeah i definately want to see that!!
do u mind if i ask how much you payed for it?
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Old Sep 26, 2012, 11:54 PM
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about aviation products

aviation products started making full scale hang gliders.
then a few shops that sold for them wanted a scale display model for the shop.
which started them making the scale models.
they are only made in 1/3 or 1/5 scale.
after scouring around the net and only finding "Really Cool Toys" that sold the same thing for around the 700 euro. which I was not prepared to pay. so was going to build my own and looking for full scale plans to base mine on, I stumbled across the site.
it is still expensive, but its a true scale model.
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Old Oct 05, 2012, 01:37 AM
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Scale Calculations

I have just finished an interesting conversation with an engineer from AirBourne hang gliders. after informing him of what I was doing with scale hang gliders he got very interested and proceeded to answer all my questions without me asking and created some more questions in the process. Mmmmmm!
ok the part that seems to pop into the mind now is weight to lift percentage of scale.

he explained to me that for instance if I built a 1/2 scale model this then has the equivalent of a 1/4 lifting weight capacity of the full size, and yes I understand that its not going to lift a fully grown man.
now what is the formula as we get further down?
does 1/5th scale drop the lift capacity down to 1/10th or are we speaking some other figure that concerns the wing area only? if so what are the figures that we should work on?
given that we know the full size dimensions to say, lift a 100 KG person of the ground.
Is a 1/5th scale capable of lifting 20KG, 10KG or 4KG.
my brain says 4KG but there must be some maths involved to prove this.

Any Thoughts?
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Old Oct 05, 2012, 01:59 AM
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Also on top of all this he explained that the rods used for the leading edge and the rest of the structure are not to scale strength wise.
so this has to be taken into consideration for scale models when you want to have it perform the same as the original in the air with a scale weight.
now how do we go about calculating diameter and wall thickness to the bendability of the main structure. if it bends more (scale wise) it will not behave the same, if it bends less (Scale wise) it will not behave the same in the air.
he added that some of this could be compensated for by having the far edge (on the tips) adjustable as on a full size one. but this would not fully compensate to give the same characteristics as a full size unit.
Love this thought process.

on top of all this the flexibility of the fabric used and its weight, will also impact on the hang gliders behaviour so to be true to scale the fabric should be 1/5th the thickness of the original and 1/5th of its weight per square foot if the scale was 1/5th.

so in a nutshell from my impression of the discussion we should think 3 dimensional and add a 4th dimension for weight. so a fifth scale we should look at 1. 1/5th the width, 2, 1/5th the length. 3. 1/5th the thickness. and 4. 1/5th the weight. and maybe 1/6th the bendability LOL.


OK time for some medication to slow the brain down. it hurts. LOL
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Old Oct 05, 2012, 01:38 PM
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The problem with scaling is that it doesn't quite work out as we can't scale air viscosity, density, reynolds numbers and other physical quantities outside the aircraft. If the length was 1/5 and the width was 1/5, the area would be 1/25 and the weight would be 1/125 if similar materials to full size were used . More brain strain, sorry.
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Old Oct 05, 2012, 06:32 PM
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Quote:
Originally Posted by Lazygit View Post
The problem with scaling is that it doesn't quite work out as we can't scale air viscosity, density, reynolds numbers and other physical quantities outside the aircraft. If the length was 1/5 and the width was 1/5, the area would be 1/25 and the weight would be 1/125 if similar materials to full size were used . More brain strain, sorry.
thats all I needed, more brain strain. so is there an overall formula to work this out in SIMPLE terms. remembering that I am a 1st grader at this.
so what your saying is a 100kg man on a full size equates to 0.8KG on a 1/5th scale. this is a strain. and how did we get to 125th is the question.

Ritchie
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Old Oct 06, 2012, 01:30 PM
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1/125 comes from 5^3 or 5 x 5 x 5. That may still be too heavy. Think of a 1/5th scale aircraft at your local club. Say a Cessna 152. Weight about 1/2 ton. If it was a 1/5th of that it would weigh about 200lb. 1f it was 1/125 it would weigh about 8lb. Round about right if you build carefully.

Now think of a P51 Mustang. 1/5th scale would have a wingspan of just over 7ft. Weight might theoretically be 9600/125 = 77lb. I think you might have problems with that, so you have to build it lighter or fly it at at least 150mph and it would stall at 100mph.

Scaling is not simple. you need to look at lots of models and pick a proved plan or kit until you have some experience. I don't have enough experience either.

This is a bit off topic for kites, the scale forum would be a better place.
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Old Oct 06, 2012, 05:16 PM
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I think Mark would be able to answer the question on how much does a full scale hang glider weigh.
I was in fact talking about the lifting capacity of a scale hang glider.

now you have just got the brain going again, does a scale hang glider fly at the scale speed of the original?
the brain says no.
so now i'm thinking what would it take to make it fly at scale speed as well?

I have used Delta Kite wings to lift motor and electronics of the ground with success. and have had this obsession for a hang glider since the 70's and never flown a full scale. but now have the opportunity to do a RC version. and I do want it to look graceful in the air as do the original.
I think Mark has come the closest that I have seen to achieving that. and the detail he puts into the build is unquestionable, the do look the part.
and they also look great in the air with the occasional fooparr in the air or contact with the ground. LOL
but he shares his knowledge and I think that is what has given me the extra push to take the plunge (so to speak).
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Old Oct 07, 2012, 03:46 AM
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hi guys, interesting reading
they reckon around 30 kilos for a lightweight training hang glider,
the topless high performance ones will be more.

microlight wings are heavier at around 50 kilos for a quik GT450 wing (kingposted) as they need to be stronger.

i really just built mine to 'look and feel right' with all the hang glider/microlight details built in- floating crossbar, fin, flexing leading edges etc.

the airframe being as resistant to crashes as it is meant that they werent really an issue in the learning phase,
not like if you was building a scale spitfire for example- one crash and its trashed

it flew well from the first test though really and a few tweaks and mods here and there have made it fly just how i wanted it to

the weight will just affect the speed at which it flies,
slightly heavier makes it more stable and direct though because of the higher wing loading, a lighter wing loading will make it floaty

a real pegasus quik 912s microlight weighs just over 200kgs empty
with a maximum takeoff weight of 450kgs
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Old Oct 07, 2012, 04:05 AM
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Quote:
Originally Posted by mark675 View Post
hi guys, interesting reading
they reckon around 30 kilos for a lightweight training hang glider,
the topless high performance ones will be more.

microlight wings are heavier at around 50 kilos for a quik GT450 wing (kingposted) as they need to be stronger.

i really just built mine to 'look and feel right' with all the hang glider/microlight details built in- floating crossbar, fin, flexing leading edges etc.

the airframe being as resistant to crashes as it is meant that they werent really an issue in the learning phase,
not like if you was building a scale spitfire for example- one crash and its trashed

it flew well from the first test though really and a few tweaks and mods here and there have made it fly just how i wanted it to

the weight will just affect the speed at which it flies,
slightly heavier makes it more stable and direct though because of the higher wing loading, a lighter wing loading will make it floaty

a real pegasus quik 912s microlight weighs just over 200kgs empty
with a maximum takeoff weight of 450kgs
That I did not look at, so I should be looking and a 125th that to be proportional scale weight or lighter. which is around 3.2Kg all up weight Vs the original 400kg.
this is quite achievable with what we have, so I'll keep that as the guide weight and lighten or add more battery if needed.
Thanks for that Mark, again you have been a great help.
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