Tigershark - ducted fan

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Tigershark - ducted fan

Postby uplink » Fri Apr 24, 2009 6:35 pm

Tigershark

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So far I've assembled ... no, lets say built, because there is a tad more construction in this one than in some ARTF 'kits' - so, I've built it, but have yet to fly it ...
I'll add to this write-up when that day has past ... whenever and however that day turns out!

The Kit came with 4 foam fus halves, (how do you manage 4 halves?) - 2 front halves and 2 back.
There's 2 wing halves with foam cores, with a very thin smooth plastic coating to them, as do the 2 tailplane halves and the fin... so, quite a nice finish on the flying surfaces. And the control surfaces come ready hinged by virtue of the fact that the thin plastic skin acts as one long piece of hinge material - obviously just how it's designed to come from the mould.

My kit came with all the usual hardware bits - some neat control horns which push through holes in the control surfaces - then a small square locking plastic plate slides down the protruding horn and via very fine grooves, which act as ratchet teeth near the horn's base, the locking plate and horn base grip the control surface which is now sandwiched between them - simple and very effective.

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Also provided was an inrunner brushless motor, ESC and the ducted fan unit.

The standard config is for 3 channels - throttle via the ESC and then you buy 2 micro servos - one in the fus for elevators fed by one snake per tailplane half, and then a servo mounted upside down and sticking out the bottom of the fus - with a linkage from each servo arm to the ailerons.

I wanted a clean underside to the fus and so opted to control the ailerons by 2 sevos - each mounted sticking out of the fus sides at the top root points of the wings - one to control each aileron.... thus now requiring 4 chan radio.

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Space in the fus makes things a bit tight, but you can make it even tighter if you free up the rudder and add another servo to control it.
As if that wasn't enought to pack into such a small craft, the instructions go on to show an option where you do minor surgery and fit a trike air retract undercarriage system!!

Being glider born and bred, I was opting for the smooth belly for landings, but then noticed how close to the ground that would put the very pointy nose, and thus the high probability of that being bent by the high speed pass of a stout dandilion!
So, I fitted the non retracting form of the undercarriage - 3 spingy wire skids....

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One important thing to note with these skids - they come formed with the bit going down to the ground doing so at 90 degrees to the ground - which skids along fine on tarmac or concrete, but on grass it does not skid !! More like emergency stops-vil !!!
So, I reformed them in a vice to 'hit' the ground (and hence the grass and worm casts) at more like 60 degrees - now it skids across grass just fine.

Esc position means it's well buried in the fus and devoid of cooling airflow - so I made a small hole in the fus next to it's location and a bit of V shaped plastic glued on to scoop the air in and keep it's electronic feet cool.

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Needs 3 cell Lipo of about 1300mAhr and these need to be 15C or above, as current draw is about 15amps, nudging 18A..... and so 10c isn't enough with a 1300mAh batt (10c times 1300mAmps gives a max safe current of 13Amps)... that's why my two 10c packs puffed up a bit, in protest, after just a couple of trial motor runs !!!

Must buy some more, but this time with a higher C rating , and get this plane in the air - two years sat on a garage shelf is no way to treat such a red, white and blue Tigershark
- just that, having had two new Lipo packs go on me so increadibly quickly - and they were my first venture into Lipos - it just put me off buying any more.
And on space and weight, for this plane, it has to be Lipos.
But, anyway, now I've reasoned exactly why my packs 'inflated', I'm happy to give Lipos another shot.

And two years on, someone still sells this plane...

http://www.modelmaniacsonline.co.uk/pro ... de=5500400

http://www.rcaircraftmodels.co.uk/1981_1_2741305.html

Appears a tad expensive 'til you include the fact, it comes complete with brushless motor and ESC controller.

http://www.youtube.com/watch?v=zNrwukmdsmw

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Now THAT'S a thermal.

Rizlaw

Postby Rizlaw » Wed Apr 29, 2009 8:11 am

wow this is a fast little item, when can we expect to see it fly at the field.

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Posts: 830
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Postby uplink » Thu Apr 30, 2009 8:55 am

When I've bought some suitable Lipos, practiced a bit more jet flying on my sim - and bought a pair of the right coloured trousers !
Now THAT'S a thermal.


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