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WHO'S BUILDING WHAT FOR 2021
- mjcp
- Posts: 183
- Joined: 29 Jul 2015, 08:14
- Location: A wind swept hill with no wind, in driving distance of Windsor, UK
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Re: WHO'S BUILDING WHAT FOR 2021
Consider also, the examples above of things failing are not equivalent to a steel blade: Rods are not blades and nor are bars.
The blade is *VERY* good at its job: resisting a bending force, when supported by the box and wing etc, in the vertical. A rod or bar will be less so, but will be better in the horizontal (not much use on a wing joiner), so its a little unfair to make them as "not as good", they are not intended to be, they are different shapes!
Here's an interesting article comparing Glass, carbon and Kevlar. Note under tensile strength, all three are pretty even! (would be good to find an equivalent for the steel bar/box for comparison) https://www.christinedemerchant.com/car ... ison.html
The blade is *VERY* good at its job: resisting a bending force, when supported by the box and wing etc, in the vertical. A rod or bar will be less so, but will be better in the horizontal (not much use on a wing joiner), so its a little unfair to make them as "not as good", they are not intended to be, they are different shapes!
Here's an interesting article comparing Glass, carbon and Kevlar. Note under tensile strength, all three are pretty even! (would be good to find an equivalent for the steel bar/box for comparison) https://www.christinedemerchant.com/car ... ison.html
m̶j̶c̶p̶ Marc
Hanger -
Some (now) pristine models that are un-flown for a year.
Hanger -
Some (now) pristine models that are un-flown for a year.
Re: WHO'S BUILDING WHAT FOR 2021
Nigel, I don’t think there is such a thing (in normal use) as an unbreakable wing joiner; all of them have their limits. It is unfortunately up to you decide the weight of the model, the proposed flight envelope and the likely loads and how aggressively you want to fly and choose/design the joiner accordingly.
14/15mm steel blade is very good and I have regularly used it in a variety of models over the years. The smaller and lighter models have had single blades while heavier, larger (4 to 5 metres or above) have had two parallel blades. These blades do bend and you may find that you may have to replace them if you have been a little too enthusiastic in your flying. I had one 1/4 scale glider where one side of the blade was almost tied in a knot. Having said that there was a Greenly tug with motor running dangling under it at the time.
I think all of the material options will work so long as you choose a size that is capable of handling the flight load x 2.
Brian.
14/15mm steel blade is very good and I have regularly used it in a variety of models over the years. The smaller and lighter models have had single blades while heavier, larger (4 to 5 metres or above) have had two parallel blades. These blades do bend and you may find that you may have to replace them if you have been a little too enthusiastic in your flying. I had one 1/4 scale glider where one side of the blade was almost tied in a knot. Having said that there was a Greenly tug with motor running dangling under it at the time.
I think all of the material options will work so long as you choose a size that is capable of handling the flight load x 2.
Brian.
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- Posts: 15
- Joined: 03 Nov 2020, 05:58
- Location: France
Re: WHO'S BUILDING WHAT FOR 2021
Brian
In the absence of being unable to calculate the size of alternative wing-joiner systems to the brass box/steel blade I will stick to that solution as it’s tried and tested. It the only sensible thing to do. I’d like to thank everyone for their input of this issue and I’m sorry if the original thread has been hijacked by this issue!!
Nigel
In the absence of being unable to calculate the size of alternative wing-joiner systems to the brass box/steel blade I will stick to that solution as it’s tried and tested. It the only sensible thing to do. I’d like to thank everyone for their input of this issue and I’m sorry if the original thread has been hijacked by this issue!!
Nigel
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- Posts: 557
- Joined: 18 Mar 2015, 20:12
- Location: Northamptonshire
Re: WHO'S BUILDING WHAT FOR 2021
Have you thought about titanium rod for joiner. Very expensive but good and light. There is a company on eBay that is selling meter lengths of grade 23 medical grade for £29. Used it in my 7 meter ash 31 after my steel bent no problem now.
- Peter Balcombe
- Posts: 1399
- Joined: 18 Mar 2015, 10:13
- Location: Clevedon, North Somerset, U.K.
Re: WHO'S BUILDING WHAT FOR 2021
What grade of steel were you using Roo?
I have a high carbon content (machine slide) rod for my 1/4 scale ASK21.
Stainless steel would be too soft.
I have a high carbon content (machine slide) rod for my 1/4 scale ASK21.
Stainless steel would be too soft.
- chris williams
- Posts: 1573
- Joined: 10 Mar 2015, 10:50
- Location: Blandford Dorset
Re: WHO'S BUILDING WHAT FOR 2021
Bergfalke progressing nicely... Span: 3.7m, current AUW ballasted for cg: 6.5lbs
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- Posts: 557
- Joined: 18 Mar 2015, 20:12
- Location: Northamptonshire
Re: WHO'S BUILDING WHAT FOR 2021
Hi Peter It was stainless 303 18 mm it has been ok on all my other gliders .but the ash 31 is was over 16 kg .using titanium and I have taken 1/2 kg of lead out of the nose. .now under 14kg.Peter Balcombe wrote: ↑18 Feb 2021, 11:31 What grade of steel were you using Roo?
I have a high carbon content (machine slide) rod for my 1/4 scale ASK21.
Stainless steel would be too soft.
- chris williams
- Posts: 1573
- Joined: 10 Mar 2015, 10:50
- Location: Blandford Dorset
Re: WHO'S BUILDING WHAT FOR 2021
A murmuration of cabrios... (Well, what else can you do during a power cut?)
- Cliff Evans
- Posts: 1035
- Joined: 29 Dec 2019, 15:13
- Location: Bristol
- Contact:
Re: WHO'S BUILDING WHAT FOR 2021
And here is the one that started it all! Modelled on the full size based in Holland.
https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
https://patteaklegliders.co.uk
- Noël Rumers
- Posts: 220
- Joined: 20 Mar 2015, 10:29
- Location: Hoboken Antwerp