1mm 31 IG-F Rohacell = 2g
0.5mm Balsa = 3g
1.2mm Herex = 5g
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| 0.5mm Balsa tailplane core = 3g |
Friday, 28 February 2014
Balsa Sandwich
Instinct F5J. After seeing the results for the core material here is the balsa core cut and weighed, the final results are...
1mm 31 IG-F Rohacell = 2g
0.5mm Balsa = 3g
1.2mm Herex = 5g
1mm 31 IG-F Rohacell = 2g
0.5mm Balsa = 3g
1.2mm Herex = 5g
Friday 28/02/2014
Instinct F5J. Friday and my day off to get stuck into some serious Instinct manufacturing.
Started with pre heating the moulds in the oven set at 40 degrees C for about 30 minutes, this gets the aluminium moulds a nice temperature for the final 2 coats of release wax.
With the epoxy mixed I started to add the Thixotropic agent 1% at a time, I thought the consistency was right at 2% but I could have gone to 5% by weight. I guess we will see what the results are like. Once rolled on in a very fine coat, not much used at all as you can see by what is left in the tray, it was a pleasure to work with and this process was over very quickly. The moulds were then put back in the oven to accelerate the gel time, this meant I could get on with some other jobs like prep the balsa for shear webs and prep all the materials ready for the lay up.
After 70 minutes in a 40 degree C oven the resin had gelled enough ready to start the lay up process. As previously mentioned all sandwich and inner layers are the same, the only difference is the outside cloth. The 1mm 31 IG-F Rohacell was quite difficult to work with over balsa as is does not want to stick to the first layer in the mould, this meant that the inside layer of 25g glass cloth was quite difficult to apply. going forward this will not be an issue as this will be done at a different stage so we can tape the cores in place so they don't move during the vacuum bagging process.
All done and good pressure, the oven set to 30 degrees C, just have to wait 24 hours to see the results!
Started with pre heating the moulds in the oven set at 40 degrees C for about 30 minutes, this gets the aluminium moulds a nice temperature for the final 2 coats of release wax.
With the epoxy mixed I started to add the Thixotropic agent 1% at a time, I thought the consistency was right at 2% but I could have gone to 5% by weight. I guess we will see what the results are like. Once rolled on in a very fine coat, not much used at all as you can see by what is left in the tray, it was a pleasure to work with and this process was over very quickly. The moulds were then put back in the oven to accelerate the gel time, this meant I could get on with some other jobs like prep the balsa for shear webs and prep all the materials ready for the lay up.
After 70 minutes in a 40 degree C oven the resin had gelled enough ready to start the lay up process. As previously mentioned all sandwich and inner layers are the same, the only difference is the outside cloth. The 1mm 31 IG-F Rohacell was quite difficult to work with over balsa as is does not want to stick to the first layer in the mould, this meant that the inside layer of 25g glass cloth was quite difficult to apply. going forward this will not be an issue as this will be done at a different stage so we can tape the cores in place so they don't move during the vacuum bagging process.
All done and good pressure, the oven set to 30 degrees C, just have to wait 24 hours to see the results!
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| Moulds pre heating ready for last 2 coats of release agent |
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| Good temperature inside the oven! |
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| Moulds completed with release agent and ready for use, very nice :-) |
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| Ready to go! |
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| Lots left in the tray, mix less next time as this goes a long way. |
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| Gel coat applied, so easy to use. |
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| Easy to see where is not covered....... |
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| First panel and 80g Spread Tow Carbon |
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| Second panel and 25g Glass Cloth |
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| Third panel and 40g Aramid Disser |
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| Fourth panel and 38g Glass Disser |
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| Bottom 2 halves completed with Rohacell and inside 25g glass cloth |
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| Top 2 halves completed with Rohacell and inside layer of 25g glass cloth |
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| In the vacuum bags and back in the oven at 30 degrees C |
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| Almost absolute vacuum - Nice! |
Thursday, 27 February 2014
Sandwich Filling!
Instinct F5J. Initial thoughts was to produce one of the test pieces using 1.2mm Herex so we can benchmark the laminate against the 1mm 31 IG-F Rohacell, but looking at the data already there is a significant weight penalty for using the Herex...... :-(
Over a 3.2m wing this will be considerably heavier so I will change the intended test layup of 40g Aramid Disser, 1.2mm Herex, 25g Glass Cloth and swap out the sandwich for 1mm 31 IG-F Rohacell...this will also give us a comparative sample against the other materials using the same core.
Over a 3.2m wing this will be considerably heavier so I will change the intended test layup of 40g Aramid Disser, 1.2mm Herex, 25g Glass Cloth and swap out the sandwich for 1mm 31 IG-F Rohacell...this will also give us a comparative sample against the other materials using the same core.
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| 1mm 31 IG-F Rohacell weighing in at 2g |
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| 1.2 Herex weighing in at 5g |
Continued Prep
Instinct F5J. Getting ready tonight for the laying up tomorrow on my day off.............no rest for the wicked!
Just pictures to show the different materials we are using.....
Just pictures to show the different materials we are using.....
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| 39g Glass Disser |
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| 40g Aramid Disser |
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| 80g Spread Tow Carbon |
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| Sandwich Material - Green is 1.2mm Herex and white is 1mm 31 IG-F Rohacell |
Mould Prep
Instinct F5J. Made a start earlier in the week and started building up the layers of release agent which in our case is Maguire's 85 wax, this has proved to be extremely easy to apply and gives a great finish.
In order to save weight we are not painting, therefore the finish will be naked cloth. In order for there to be no compromise in the surface finish we will be using the laminating resin as a gel coat. Order received from R&G Composites of Thixotropic Agent and 285 Epoxy Hardener from PRF Composites, the Thixotropic agent is added to the resin mix by up to 5% by weight, this will enable a very thin layer to be applied to the mould surface to create a film which will provide a great surface finish. The new hardener will be used as this has a shorter pot life and gel time which will enable a speedier process, once applied the moulds will be placed in the oven at 35 degree C for 60 minutes which is long enough to 'gel'.
we can then lay up the material in the moulds in the usual way.
In order to save weight we are not painting, therefore the finish will be naked cloth. In order for there to be no compromise in the surface finish we will be using the laminating resin as a gel coat. Order received from R&G Composites of Thixotropic Agent and 285 Epoxy Hardener from PRF Composites, the Thixotropic agent is added to the resin mix by up to 5% by weight, this will enable a very thin layer to be applied to the mould surface to create a film which will provide a great surface finish. The new hardener will be used as this has a shorter pot life and gel time which will enable a speedier process, once applied the moulds will be placed in the oven at 35 degree C for 60 minutes which is long enough to 'gel'.
we can then lay up the material in the moulds in the usual way.
The New Begining
Instinct F5J. The F5J version of the Instinct is now underway........
This will be a light version of the F3B model we produced some undisclosed number of years ago, the target flying weight for the windy weather model (Instinct XL) is currently 1.6kg +/- 150g and the lightweight version (Instinct XXL) is 1.3kg +/- 100g.
We are starting the journey by producing some sample pieces so we can record weights for different lay ups vs strength, these will be tailplane quarters which will give us 4 test pieces per building process. The first 4 samples being made tomorrow will be of the following construction.
1. 25g Glass Cloth, 1mm 31 IG-F Rohacell, 25g Glass Cloth
2. 39g Glass Disser, 1mm 31 IG-F Rohacell, 25g Glass Cloth
3. 80g Spread Tow Carbon, 1mm 31 IG-F Rohacell, 25g Glass Cloth
4. 40g Aramid Disser, 1.2mm Herex, 25g Glass Cloth
Following the de-moulding of these samples we aim to produce the following additional samples...
5. 90g Carbon Plain Weave, 1mm 31 IG-F Rohacell, 25g Glass Cloth
6. 50g Glass Cloth, 1mm 31 IG-F Rohacell, 25g Glass Cloth
7. 80g Glass Cloth, 1mm 31 IG-F Rohacell, 25g Glass Cloth
8. 40g Aramid Disser, 0.5mm Balsa, 25g Glass Cloth
Updates will be forthcoming as and when progress is made....stay tuned!
This will be a light version of the F3B model we produced some undisclosed number of years ago, the target flying weight for the windy weather model (Instinct XL) is currently 1.6kg +/- 150g and the lightweight version (Instinct XXL) is 1.3kg +/- 100g.
We are starting the journey by producing some sample pieces so we can record weights for different lay ups vs strength, these will be tailplane quarters which will give us 4 test pieces per building process. The first 4 samples being made tomorrow will be of the following construction.
1. 25g Glass Cloth, 1mm 31 IG-F Rohacell, 25g Glass Cloth
2. 39g Glass Disser, 1mm 31 IG-F Rohacell, 25g Glass Cloth
3. 80g Spread Tow Carbon, 1mm 31 IG-F Rohacell, 25g Glass Cloth
4. 40g Aramid Disser, 1.2mm Herex, 25g Glass Cloth
Following the de-moulding of these samples we aim to produce the following additional samples...
5. 90g Carbon Plain Weave, 1mm 31 IG-F Rohacell, 25g Glass Cloth
6. 50g Glass Cloth, 1mm 31 IG-F Rohacell, 25g Glass Cloth
7. 80g Glass Cloth, 1mm 31 IG-F Rohacell, 25g Glass Cloth
8. 40g Aramid Disser, 0.5mm Balsa, 25g Glass Cloth
Updates will be forthcoming as and when progress is made....stay tuned!
Friday, 21 February 2014
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