Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 22 Mar 2018, 14:36
I trust it will get a tow release......
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Purbeck 1/3rd Scale DG800 Build Thread
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Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 22 Mar 2018, 16:44
Nice one Simon, see I said you would get back to big
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 22 Mar 2018, 16:46
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 22 Mar 2018, 17:12
looking forward to this one. will it be flying this year simon???
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 22 Mar 2018, 17:47
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 22 Mar 2018, 20:26
Nice to see your off with start number two Simon.
You've certainly started with a bang, a lot done in one day ,look out Roo and Paul W. he will take the prize for first in the air if we let him.
As already mentioned all three models were prototypes. Each with a different lay-up and finish.The intention was to produce a model with a similar spec as the very popular ASW 27. The wing lay-up of your no2 kit has a full length, top and bottom spar with a carbon vertical section making it into an 'I' beam spar,The wing joiner is incorporated, and is an integral part of this spar.There are three 150g glass interweave cloths. The first covering in an elliptical manner the wing joiner block and front and rear incidence blocks,the weave placed diagonally to the span. The second leaf was taken from the root to beyond the air break position with the weave span wise. the third and final leaf was taken from root to the whole length and cord of the wing.Carbon tows were layed into the trailing edge for stiffeners and to allow sanding to a sharp edge without the edge wandering from the straight. The spoiler channel was fitted, the low voltage drop cables to the 5in No servo positions in each half span. Last but not least the full length hing line was fitted with peel ply to make the living hinge which you have mentioned. All was then uncased into 1.2mm obechi veneer epoxy bonded, into the vac bag and low temp oven overnight and one day.
The following few days, while on test it showed that due to the long half span and short cord,coupled with a reasonable thin but changing section, the wing did show more flexibility then we wanted,so the following two prototypes were layed-up the same but changed the third full length interleave of glass to one of carbon cloth. This certainly made the wing much stiffer as you noticed with your first kit.
However a hand built wing of this complexity was becoming overly expensive to produce for mass production, hence only the three were ever made.
Don't think that the flexibility of the wing will lessen its strength in any way,That wing is incredibly strong where it is required to be.In the past I often gave talks to surrounding clubs on club nights. Any who were in attendance will tell you that for the party finish I would span a wing across the back two chairs at the tip and the root and then stand a medium size car battery in the middle of the wing, leaving it there while I took question and answers,just to show how strong Purbeck wings were,
Can anyone out there remember this?
Well done Simon, I'm here if need me. Terry (Purbeck sailplanes)
You've certainly started with a bang, a lot done in one day ,look out Roo and Paul W. he will take the prize for first in the air if we let him.
As already mentioned all three models were prototypes. Each with a different lay-up and finish.The intention was to produce a model with a similar spec as the very popular ASW 27. The wing lay-up of your no2 kit has a full length, top and bottom spar with a carbon vertical section making it into an 'I' beam spar,The wing joiner is incorporated, and is an integral part of this spar.There are three 150g glass interweave cloths. The first covering in an elliptical manner the wing joiner block and front and rear incidence blocks,the weave placed diagonally to the span. The second leaf was taken from the root to beyond the air break position with the weave span wise. the third and final leaf was taken from root to the whole length and cord of the wing.Carbon tows were layed into the trailing edge for stiffeners and to allow sanding to a sharp edge without the edge wandering from the straight. The spoiler channel was fitted, the low voltage drop cables to the 5in No servo positions in each half span. Last but not least the full length hing line was fitted with peel ply to make the living hinge which you have mentioned. All was then uncased into 1.2mm obechi veneer epoxy bonded, into the vac bag and low temp oven overnight and one day.
The following few days, while on test it showed that due to the long half span and short cord,coupled with a reasonable thin but changing section, the wing did show more flexibility then we wanted,so the following two prototypes were layed-up the same but changed the third full length interleave of glass to one of carbon cloth. This certainly made the wing much stiffer as you noticed with your first kit.
However a hand built wing of this complexity was becoming overly expensive to produce for mass production, hence only the three were ever made.
Don't think that the flexibility of the wing will lessen its strength in any way,That wing is incredibly strong where it is required to be.In the past I often gave talks to surrounding clubs on club nights. Any who were in attendance will tell you that for the party finish I would span a wing across the back two chairs at the tip and the root and then stand a medium size car battery in the middle of the wing, leaving it there while I took question and answers,just to show how strong Purbeck wings were,
Can anyone out there remember this?Well done Simon, I'm here if need me. Terry (Purbeck sailplanes)
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 23 Mar 2018, 06:16
Thanks Terry - great to have that info. I'll try to limit the number of stupid questions I ask!
The added glass and Kevlar in the fuselage has made a huge difference to the stiffness so now I'll start adding ply bulkhead corners to add crush resistance around the wing joiner and incidence pins.
I'm actually enjoying it again!
Simon
The added glass and Kevlar in the fuselage has made a huge difference to the stiffness so now I'll start adding ply bulkhead corners to add crush resistance around the wing joiner and incidence pins.
I'm actually enjoying it again!
Simon
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 23 Mar 2018, 10:44
Si,If getting you to enjoy your modelling again is all that the DG 800 achieves, it will be well worth while. Ter.
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 23 Mar 2018, 20:12
Glad to hear you have found your bag of "mojos" Simon....
Re: Purbeck 1/3rd Scale DG800 Build Thread
Posted: 23 Mar 2018, 23:34
But he is still looking for his tow release.....
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