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Tragi 702 Review

by Pete Rundle as seen in QFI 48

I had heard a bit of a buzz about the Tragi 702; F3F ace Espen Torp had one and was said to be impressed. An opportunity to get my hands on a 702 presented itself thanks to Europa Competition Gliders and so my Tragi was duly ordered.

The Tragi line of sailplanes dates back several years. The designer and producer, Heino Korvel, hails from Estonia, also where the Tragi is produced. The subject of this review, the Tragi 702, has a contemporary sister the Tragi 701. Although outwardly similar the 701 uses the MH32 wing section whereas the reviewed 702 uses a modified (thinned) RG15 and is probably more suited to slope work.

The model supplied by ECG is described as a double carbon version. In Tragi nomenclature this means that the wing has a layer of carbon fibre in the outer skins of both the centre and tip panels. There is also a single carbon version that only has carbon in the centre panel wing skin, and of course, there is a standard glass version.

My new Tragi’s first F3F competition outing resulted in a win at East Sussex with subsequent jaunts realising two new personal best times! That model however is not the subject of this review (Eh? KN).

Suitably impressed I ordered another Tragi, this time a PNS version, and it is this model that’s the subject of this review (Ah, I see, phew! KN). The PNS is rumoured to stand for Preben Norholm Special. Preben is widely regarded as the father of F3F and the special relates to the increased amount of glass fibre used during the model’s construction.

What do you get?

A beautiful, crisply constructed, moulded wing consisting of three panels. There is nothing unusual here except for the wing joiners. Most moulded glider wing joiners are solid carbon fibre affairs however the Tragi’s are a carbon-balsa-carbon sandwich, rather like most wing spars are constructed. They are of a much larger cross sectional area than normal but remain extremely light. Being so large they convey a lot of torsional rigidity to the tip panels but the sandwich means they’re also likely to snap readily in an impact, theoretically saving the wing in the event of a nasty.

Unusually these days, the apertures for the servo bays are not cut out for you. However they are very clearly marked and it’s only a few minutes work with a mini-drill to gain access. Once exposed, the internal structure of the wing is extremely neat, no great globs of microballoons dangling all over the place in this one! The sub spar at the trailing edge looks to be balsa with a carbon fibre shear-web. Even though the wing only has carbon fibre on the outside of the wing skin sandwich the whole unit is very rigid.

A job that is done for you (and a source of much stress if it isn't!) is the fixing holes for the control horns. The control surfaces have been locally filled with what looks like an epoxy and microballoon mix and then drilled to be a good close fit for the brass horn units supplied.

The Tragi range traditionally has wing mounted ballast and the 702 is no different. This has to be the feature that I like least about this model. Personally I would much rather have the ballast in the fuselage. It’s so much easier to change ballast quickly by whipping the nosecone off and adding or dumping a few slugs of lead, rather than fumbling about with a hatch in the wing and worrying how many ballast slugs are on each side. Having said that the system is well executed with an accurately fitting hatch giving access to a nicely moulded ballast tube that sits up against the main spar.

Next the tailplane which is a masterpiece and must rate as the best moulded tail I have seen. It’s big, light and practically bullet proof! The area where most moulded tailplanes fall down is the very tip where the spar and the elevator hinge-line end. This is usually just left as unsupported glass skin and leads to nasty creases from only very slight mishandling (been there, got that T shirt!). No way is this going to happen with the Tragi tail. Again, the sub-spar just in front of the hinge-line has a carbon fibre shear-web effectively meaning the tail has got two spars. This makes it very stiff and torsionaly rigid. The uncanny bit is that this has been accomplished without a perceptible increase in weight.

Still on the tail the torque rods are already fitted to the elevators and terminate in brass balls that have already been soldered on. There is a captive nut moulded into the centre of the tail to take the single fixing bolt that fits through a hole in the bottom of the tail boom and pulls the tail down onto its seat.

Next the fuselage. The Tragi 702 being young and trendy has gone down the pylon mounted wing route. I assume the complex moulding needed to achieve this is made possible by the use of a "waistline" join such as that used on the V-Ultra Pico and the even more recent Sting. The first thing that strikes you is how light the moulding is, especially at the tail end. The main moulding appears to be Kevlar with a carbon fibre spine top and bottom of the tail boom. There is a tape-on fairing for the end of the fuselage allowing easy access for fitting the tailplane and connecting the linkages. When fitted the tail end really is neat.

The pylon wing seat is a good fit with the wing centre section and has the wing fixing nuts ready moulded in. There is also a box moulded in to take the supplied 9-pin D connector used to connect the aileron and flap servos. At the front end instead of the more usual inner nosecone there is a vertical keel. Mind you it’s a keel and a half! Whereas others have got by with quite floppy affairs, relying on the outer nose sheath being pulled tight by a fixing bolt, this one is very substantial. It is moulded as an "I" beam and very heavily flared into the bulkhead area. I doubt if it would fail in a major impact (when I find out I’ll let you know!).

The outer nose sheath is another nice Kevlar moulding, being light and rigid. The friction push fit onto the keel moulding is just right and oozes quality. The aluminium pushrods are already in place and are fitted with the ballcups that clamp to the elevator torque rod ball ends. The front of the rods are neatly sleeved down to 2mm threaded steel and there’s plenty of excess length, so servo positioning is not compromised. Finally there is slot moulded into the bottom of the fuselage for fitting a tow hook. The hook itself clamps in place with a socket cap screw and washer, all of which are supplied.

Interestingly the bag containing the flap and aileron horns includes a little piece of paper proclaiming that these horns are "servo savers". Apparently they are supposed to fracture if the control surface is knocked hard, for example if you don't tuck the crow brakes in quickly enough. I must admit to being a mite doubtful. The screw in bits look identical to the usual units, no partial saw cuts or anything to actively make them frangible. Anyway they are more than adequate for the purpose of waggling the hinged bits, so enough said. Also included is 2 kilos of ballast. This comes wrapped in lots of cardboard and glued to the inside of the shipping box to stop it destroying everything in its path!

Assembly

I hesitate to call it building and won’t give a blow by blow account of everything. Anyone buying one of these is likely to be experienced enough to have their own ways of doing things.

I will however point out bits that I think may be of interest.

Wing

Once the servo apertures had been opened up patches of carbon fibre cloth could be seen locally strengthening the wing skin where the servos were to be epoxied. This is more than most manufacturers do but personally I feel even this may not be robust enough to withstand ripping a servo out too often. Also being a concave shape it is not the ideal profile to glue to. The first job I do on a new moulded model is to make 1/32" ply plates as wide as I can fit through the servo access hatch and long enough to extend span wise a good 2 or 3 centimetres either side. These are glued into the wing using epoxy and microballoons. I then bridge the top and bottom skins around the servo bay with blue foam blocks carefully fitted so as not to bulge the wing. When glued in, the servos are extremely rigid and attach very well to the plywood.

I used Multiplex Micro MC V2’s in the wing. Even though these are really mini rather than micro they fit in without protruding. Mind you, you’ll have to cut the mounting lugs off! (This is because my added reinforcement leaves less depth for installation.)

Everything is straightforward as regards fitting the control horns. They’re a nice fit in the pre-drilled holes and just need gluing in with epoxy. Another job that's done for you is the fitting of the tip panel alignment pegs. If you've ever tried this yourself you'll be as grateful as I was that it’s been done in the Tragi factory!

Tail and Fuselage

There is nothing to do to the tailplane, just screw it onto the fuselage and push the ball and socket joints together. I taped the ruddervators at neutral so the pushrods can be cut to the right length.

Up at the other end of the fuselage the flight pack needs to be fitted. This is where I encountered the only real problem. When fitting my fuselage wiring loom through the D connector hole I couldn’t get it as far as the aperture I’d cut in the keel bulkhead. Squinting through the slot I had cut revealed why. As is common with a lot of moulded gliders there is a bulkhead halfway down the tail boom, a little more unusually the Tragi also has two additional bulkheads in the wing seat area, one of which is forward of the D connector mounting box. This is great for pushrod rigidity the problem though is that there is only a 9mm hole in the centre of it to take the wiring loom. I had two options, either take all the Rx connectors off, or make the hole bigger. I plumped for the latter.

I had cut a slot big enough to take the full width of the ribbon cable in the bulkhead so I had no trouble getting a long coarse file in and riffling the hole bigger. The bulkhead seems to be very thin so the job didn’t take too long.

A couple of minutes with a bit of bent wire had the Rx end of my loom in full view and I could get on with the remainder of the gear installation. The nosecone has enough internal diameter to comfortably accommodate the depth of two Multiplex Micro MC V2 Speed mini servos. There is plenty of space to mount the rest of the flight pack, as the keel is nice and long. I always use a five-cell battery pack and had no trouble fitting 1400mAh NiMH pencells.

SETTING UP

I had set my first Tragi up initially using the data sheet supplied by Tun Modellbau (included with the model) and found this to be a good starting point. The only parameter found to be way out was the elevator compensation when crow braking (I doubled it from 1.5mm to 3mm down elevator at full crow). For my own taste I increased aileron and elevator throws. I tend to fly with the model quite sensitive and use small movements of the sticks. The Tragi PNS was programmed with exactly the same movements as my first Tragi. As to the C of G, I balanced the model in the middle of the suggested range at 98mm from the leading edge of the wing centre section.

FLYING

Having got used to flying the lighter double carbon Tragi this was going to be interesting. I had found that with the carbon model a little ballast was always necessary, even in very light lift, in order to keep the handling purposeful. In very strong lift, or if the wind was cocked off to one side, I found that this model relished full ballast.

The maiden flight took place off "Micky's Slope" which is the south-westerly face of my local mountain, the Bwlch. The wind was moderate and fairly straight onto the hill. As you would expect, no trim changes were necessary so I happily wound her up to a good height before executing the first of many speed runs that afternoon. Like my first Tragi the handling is impeccable. I can honestly say that the Tragi 702 is the nicest moulded model that I have flown. The controls are extremely well harmonised and the model is really easy to fly.

The model is a bit bigger than a lot of the competition; the strange thing is that this does not show up in the handling. The aileron response is quite spectacular for a model of this size. With the suggested 60% differential and a little aileron to flap mix axial rolls in 2 seconds are easy! This is probably due to a combination of its high torsional rigidity and very generously sized ailerons. The roll response does not seem to diminish when adding ballast. I had thought that with 2 kilos of ballast spread the whole length of the centre section there would be a significant dumb-bell type inertia going on, but that does not seem to be the case. With a bit of ballast the Tragi 702 makes a superb aerobatic machine. As with most models of this ilk, their sheer energy retention, speed and accuracy make sport flying a real buzz.

Now down to the important bit, for me anyway, how does she fly on an F3F course? The Tragi is very well harmonised and easy to fly. Being quite big and a lot of the time quite heavy she has a very solid feel on the course and grooves extremely well. As I said earlier, this model loves ballast and in good lift or high winds can easily carry all 2 kilos. The amazing bit is how well the Tragi can crank such a load around the corners so well. This is probably what makes her such a good F3F machine. Even in very light conditions there is a feeling of grip, almost, yes you knew it was coming, like she‘s on rails...

The trend these days seems to be for quite small snapflap deflections, typically 3mm or so. The Tragi set-up sheet recommends 6mm. I have settled on about 5mm with or without reflex. The 702 seems to respond well to a bit of reflex; you don't get that awful sinking that some other gliders inspire when the reflex is switched in. I have gone slightly above the suggested 1mm reflex and use about 1.5mm, but I can adjust all my mix ratios on the hoof with the brilliant Futaba 9ZAP making setting up a new plane a doddle.

Final thoughts

You have probably guessed that I like this model and you would be right! For a while I have been looking around for a model that suited my style of racing and I can honestly say that I think I have found it.

There is a slight difference between my two Tragi’s, The lighter double carbon version is a bit more "bouncy" in very light conditions but does not like flying unleaded. The PNS fly’s fine with no ballast in light conditions and in moderate winds it is possible to over ballast. I think that if I wrote off the lighter one I would think very seriously about replacing it with the same. It feels to me as though the lighter, but admittedly not so robust, airframe is slightly more nimble in very light lift, but with either model you’ll have a very potent F3F machine.

If you want a Tragi of either type, they are available from Soarhigh, who can be contacted at:

6a The Square
Turriff
Aberdeenshire
Scotland
AB53 4AH
Tel +44 (0)1888 560446
Fax +44 (0)1888 563251

E-mail address - guy@soarhigh.co.uk
Web address - http://www.europa-gliders.co.ukwww.europa-gliders.co.uk

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