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Old Jan 20, 2013, 09:52 AM
Painter S is offline
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Joined Jun 2009
105 Posts
Hello again Ian,

It took me a long time since my post #40, but I did finally get round to building a fuselage along the lines you have described.I was originally interested in a producing a lightweight model for my Pike Perfect ET wings but in the event decided to make a fuselage to suit both the Pike wings and those from my 4m Hyper Ava.I have followed what you have done very closely so will only give details of any areas of difference.

I have used all the same components :-

M2A-e pod from http://www.kristoffair.co.uk/products
Tailboom,V mount,pushrod components,carbon from http://www.hyperflight.co.uk/
Balsa etc from my 'bits box '

Wing seat

The wing fixing hole centres on my Pike and Ava wings are 127.5 and 120 mm respectively.These are right at the limit of the seat opening on the pod and so I could not use the same fixing as you did.I built up a sort of outrigger at the back of the opening to house the captive nuts.This is shown on the attached photos.The nuts are in the form of tapped(M4) aluminium sleeves about 5.75mm dia and 19mm long.They are expoxied into the wooden inserts.I made them up myself but commercial steel ones could easily be substituted.
The wing seat itself is made from two layers of 0.8mm ply and one layer of 200 gsm carbon.It is the same dimensions as the Hyper Ava seat.
As you can see from the photo I had to sand it away quite a bit at the front to get a snug fit.If I did another I would use three layers of ply.The Pike wings are fitted with the aid of an adaptor plate made from a couple of bits of balsa.

Tail set

The fin and rudder are simply an enlarged copy of a Bubble Dancer tail.The linear dimensions have been increased by about 15% which gives an area increase of about 32%.This gives a vertical tail with a slightly larger area than the Hyper Ava tail.The construction is all balsa ,with the exception of the fin spar which is reinforced by a full length carbon strip.I though this might give a bit more strength for the larger tail.

Originally I was going to make a BD horizontal stab,which I have used on a couple of other models.In the event I took the easy way out and decided to use the stab from my Hyper Ava.It can easily be switched between models using only one screw.
The finished weight of the complete tail set including horn etc was 56 gms-Very similar to yours.

Pushrods

Pushrods are externally mounted on the top of the boom.They comprise 1mm carbon rods in 1.3 mm etched teflon tubes.As the moment they are taped to the boom until such time as I can get a test glide to make sure the stab is at the right angle.I will then glue them with thin cyano.
Weights

The total ready to go weights worked out slighly lower than my initial targets.

The weights with the Ava and Pike wings are 1486 gms(52.5 oz) and 1733 gms(61.2 oz) respectively giving corresponding wing loadings of 5.6 and 7.2 oz/ft2 .

Balance.
The Rx is mounted on a balsa tray just under the front of the wing seat .It is high enough to allow the battery(TP 1300 3S 65C) to slide underneath right as far back as the servo tray.Despite this, when I fitted my original drive(Mega 16 EDF on Reisenauer box-113gms) the model would not balance.Reluctant to add weight to the tail I replaced the motor with a Hyperion Heli motor(HS 2216) on the same box.This drive weighs 89 gms and with it in place the model will balance with both sets of wings comfortably.I have given it a good work out and it looks to be good for 400 Watts or so without getting too hot.This power should be fine for the Ava wings.It might be a bit light for the Pike wings-Time will tell.
As it stands the model is best suited to a lightweight set up.To use a heavier drive or battery would need either tailweight or the nose cutting a bit shorter.

So, it has all worked out very well.I have finished up with an alternative lightweight set-up for a couple of my models at a very reasonable cost.As you have also demonstated, this route is well suited to producing an Esoaring model using an existing pair of wings.

I have yet to try it out but as it is aerodynamically similar to the Hyper Ava(which I have also flown with the Pike wings) I am not expecting any real surprises.It will be interesting to see what differences the ligher overall weight and lighter extremities make.

Spencer.
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Last edited by Painter S; Jan 21, 2013 at 02:54 AM. Reason: spelling
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