Friday, 14 March 2014
The New Tailplane
Instinct f5J. I am back from my trip and everything went well :-)
Opening the moulds saw immediately that the surface finish was amazing, extremely smooth and no blemishes, the carbon leading edge looks great and certainly adds strength, too much so we will be leaving this out in future to get the weight down further. With the main spar being moved forward to allow for the space for the servo, this makes the tailplane very stiff as the load is spread over the 3 spars more equally, this is a great by product.
The weight is slightly heavier than we intended, but we can save even more next time :-).
Another one is being prepped to start over the weekend......
Opening the moulds saw immediately that the surface finish was amazing, extremely smooth and no blemishes, the carbon leading edge looks great and certainly adds strength, too much so we will be leaving this out in future to get the weight down further. With the main spar being moved forward to allow for the space for the servo, this makes the tailplane very stiff as the load is spread over the 3 spars more equally, this is a great by product.
The weight is slightly heavier than we intended, but we can save even more next time :-).
Another one is being prepped to start over the weekend......
Monday, 10 March 2014
Tailplane Joining
Instinct F5J. After the inside layer cured and was removed from the oven, the shear webs for the main spar were cut from pre laminated 4mm Rohacell 51 IG-F with 25g glass cloth laid at a 45 degree bias on both sides of the web. The reinforcements either side of the elevator hinge line are made from drinking straws and carbon sock, these are perfect as it reduces the weight as they squash to the exact shape. Cutting a shear web is too tricky as there is hardly any depth, the straws make this very easy.
A mix of epoxy resin, cotton flock and micro balloons is piped to the leading and trailing edges and is also used to join the main shear web. Cotton flock is a glass fibre based reinforcement which looks like very tiny pieces of cotton wool, these ensure that the epoxy is bound together and not brittle, this is where the real strength of the join comes from. The micro balloons are microscopic balls of fibre glass almost like glass dust, these are extremely light weight and are used to bulk out the resin mix without any weight penalty, this makes the paste like mix go further and reduce the overall weight of the finished product.
With the moulds carefully trimmed the paste mix is put in a bag, the corner of the bag is cut off and now we apply the mix to the prepared skins like icing a cake. The carbon socks with straws inside are wetted out and placed carefully to the exact measurements, the shear webs are added and then the top mould is married up with the bottom mould and then clamped together. This is placed back in the oven at 30 degrees for 24 hours and then the temperature is increased to 50 degrees for 10 hours which will post cure and harden even further the resin and the finished tailplane. I am away for a few days in Germany with work so I will be de-moulding and sharing the results when I get back on Friday........ :-)
A mix of epoxy resin, cotton flock and micro balloons is piped to the leading and trailing edges and is also used to join the main shear web. Cotton flock is a glass fibre based reinforcement which looks like very tiny pieces of cotton wool, these ensure that the epoxy is bound together and not brittle, this is where the real strength of the join comes from. The micro balloons are microscopic balls of fibre glass almost like glass dust, these are extremely light weight and are used to bulk out the resin mix without any weight penalty, this makes the paste like mix go further and reduce the overall weight of the finished product.
With the moulds carefully trimmed the paste mix is put in a bag, the corner of the bag is cut off and now we apply the mix to the prepared skins like icing a cake. The carbon socks with straws inside are wetted out and placed carefully to the exact measurements, the shear webs are added and then the top mould is married up with the bottom mould and then clamped together. This is placed back in the oven at 30 degrees for 24 hours and then the temperature is increased to 50 degrees for 10 hours which will post cure and harden even further the resin and the finished tailplane. I am away for a few days in Germany with work so I will be de-moulding and sharing the results when I get back on Friday........ :-)
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| Cutting the main shear web from laminated 4mm Rohacell 51 IG-F |
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| Dry fitting the main shear web and straw spars |
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| Carefully trimming the excess cloth from the edges of the skins |
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| Cotton Flock |
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| Micro Balloons (Glass Bubbles) |
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| Dry weight of shear webs and spars |
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| Wetted weight of shear webs and spars |
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| Piping on the paste mix which joins the leading and trailing edges together |
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| Everything complete and ready for joining |
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| Clamped and in the oven ready for baking... |
New Tailplanes
Instinct F5J The tailplanes were taken out of the oven and the inner layer added, this is 25g glass cloth, also the carbon spar caps 80g UD carbon and the servo reinforcement 80g TeXtreme Spread Tow, this was then vacuum bagged again and left to cure for 24 hours at 30 degrees.
Friday, 7 March 2014
New Tailplane
Instinct F5J. Today saw the production of our first tailplane, using 25g glass, 1mm Rohacell and 25g glass. We have added a single 12k carbon tow to the leading edge on both the top and bottom halves, also some 80g unidirectional strengthening at the root.
This is now under pressure and in the oven and will be ready tomorrow for the next stage of adding the spar caps and inside layer of cloth after the rohacell has been prepared ready for joining.
This is now under pressure and in the oven and will be ready tomorrow for the next stage of adding the spar caps and inside layer of cloth after the rohacell has been prepared ready for joining.
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| Top with carbon reinforcement and 25g glass cloth |
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| Bottom with carbon reinforcement and 25g glass cloth |
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| In the vac bags and placed in the oven |
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| Great pressure today - absolute vacuum!!! |
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| The oven with the moulds inside...... |
New Material Has Arrived
Instinct F5J. The new material has arrived today from R&G and Hyperflight.
30 degree bias 39g Spread Tow Carbon for a really lightweight 'D' box, 80g unidirectional carbon for wing strength reinforcements, 30g unidirectional tape for lightweight stiffening of the tailplanes and 49g glass cloth.
All really nice and a fantastic service from R&G again! :-)
30 degree bias 39g Spread Tow Carbon for a really lightweight 'D' box, 80g unidirectional carbon for wing strength reinforcements, 30g unidirectional tape for lightweight stiffening of the tailplanes and 49g glass cloth.
All really nice and a fantastic service from R&G again! :-)
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| 30 degree bias 39g Carbon Spread Tow |
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| 30g 20mm wide unidirectional carbon |
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| 80g unidirectional carbon |
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| 49g Glass cloth |
Work on the fuselages starts here...
Instinct F5J. Over the years, the Instinct wing and v-tail has sat on a few fuselages but the majority have been mounted on the Tracker fuslage. When we decided to re-start production, we went back to Rick and Bill at Lite Flight UK and were really happy to find out that this option is still available. Below is photo showing how the front end of the Tracker has been modified since we last bought one.
Before seeing the changes, we were worried that cutting part of the nose off to fit a motor would leave us with a very short nose moment. Happily, the nose moment has increased, which enables us to consider putting the servos in the v-tail, rather than in the fuselage. We'll have to see how this goes in the test pieces that Neil is making. Luckily, there's loads of room in the fuselage for batteries etc, so we can move these around to balance the model.
We're planning on fitting a 32mm spinner to the nose and mounting the motor/gearbox a little further back than is shown currently but not too far back - a centimeter or two, max.
The photo below shows that the fuselage is oval, but it also has just enough give, to enable a round mounting plate to be installed. The oval shape is then considered to be benficial as any wires can be kept away from internal rotating parts, if we go for an outrunner motor.
We're planning on fitting a 32mm spinner to the nose and mounting the motor/gearbox a little further back than is shown currently but not too far back - a centimeter or two, max.
The photo below shows that the fuselage is oval, but it also has just enough give, to enable a round mounting plate to be installed. The oval shape is then considered to be benficial as any wires can be kept away from internal rotating parts, if we go for an outrunner motor.
That's it for my first entry - more will follow when the other bits start arriving. Just need to keep up with Harry now...
New Tailplane
Instinct F5J. We are ready to start building the first tailplanes, the first will be 25g glass, Rohacell, 25g glass then we are going to try the 50g glass on the outer skin, this will give us some good weight comparison vs strength and dent resistance. Once we are happy with the results we start our first wing.
To ensure that the cloth is pressed nicely into the complex curves of the mould both at the leading edge and the tips we chamfer the edges of the Rohacell, this reduces the 'step' and prevents air being trapped, this also increased strength and gives a blemish free surface finish at the edges of the core material. This is tedious and time consuming but well worth the extra effort.
To ensure that the cloth is pressed nicely into the complex curves of the mould both at the leading edge and the tips we chamfer the edges of the Rohacell, this reduces the 'step' and prevents air being trapped, this also increased strength and gives a blemish free surface finish at the edges of the core material. This is tedious and time consuming but well worth the extra effort.
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| Chamfering the edges of the Rohacell for the tailplane |
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| Top & Bottom, Left & Right cores ready for lay up |
Saturday, 1 March 2014
Great Result
Instinct F5J. 24 hours later and we have de-moulded the samples and what a great result! The surface finish is fantastic and completely smooth. See below photos and the weigh in...
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| All test pieces together |
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| 25g Glass Cloth = 10g |
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| 38g Glass Disser = 11g |
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| 40g Aramid Disser = 11g |
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| 80g Carbon Spread Tow |
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| Close Up - 25g Glass Cloth |
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| Close Up - 38g Glass Disser |
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| Close Up - 40g Aramid Disser |
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| Close Up - 80g Carbon Spread Tow |
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