Making a start on the fuselages

Having received the components that we need to complete the motor installation, I have now worked out how to do it for one fuselage, so the other one should follow quickly.

The ‘problem’ is that the fuselage is not round but oval, everything else is round.  The motor also has the wires coming out of the side, between the gearbox and the motor – which is an out runner, so could damage the wires if they touched the motor.

So lots to the think about.  One last thing, the spinner size – we have to make sure that the fuselage diameter roughly matches the standard spinner diameters.

When all of these come together we get the following:

I've yet to glue this in place and then finish the fuselage so it's perfectly flush with the motor mount but this will follow soon.  I also need some screws to mount the motor on the plate.  I'm hoping Richard from T9HobbySport can help with this.

Next step is to order the speed controllers and batteries.  I'll then start to balance the fuselage - just roughly.

Mould Modification

Instinct F5J.  Well we had a short holt on the production of gliders to modify the moulds which has taken a lot longer than ever anticipated, but we are now in a position where we can continue.....thank the good lord :-)

The issue was that the moulds had a trough in front of the leading edge which was supposed to aid with trimming the excess cloth to size before joining together, also acting as a void for any excess resin and joining paste to go without affecting the surface finish.  The problem came when the cloth under the pressure of the vacuum was being stretched between the trough and the compound curve of the leading edge shape, this showed where the cloth could not be forced into the leading edge curve and not touching the surface of the mould, this can be seen on the finished product as air bubbles.

The only fix was to fill the leading troughs on all of the moulds, this took about 1kg of resin and 2 hours of prep work, 4 hours of filling followed by 3 days of curing and a massive 16 hours of sanding.  The results are great and this will be reflected in the new finished moulded products, the first new tailplane will be laid up this weekend with the hope that we can start production of the wings the following weekend.

Hopefully we are now back on track.................

Tailplane Detail

Instinct F5J.  Tailplane detail pictures for your enjoyment! :-)

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......

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........ :-)

Cutting the main shear web from laminated 4mm Rohacell 51 IG-F

Dry fitting the main shear web and straw spars

Carefully trimming the excess cloth from the edges of the skins

Cotton Flock

Micro Balloons (Glass Bubbles)

Dry weight of shear webs and spars

Wetted weight of shear webs and spars

Piping on the paste mix which joins the leading and trailing edges together

Everything complete and ready for joining

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.

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.

Top with carbon reinforcement and 25g glass cloth

Bottom with carbon reinforcement and 25g glass cloth

In the vac bags and placed in the oven

Great pressure today - absolute vacuum!!!

The oven with the moulds inside......