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Viking Review

By Kevin Newton as seen in QEFI 31

Download this 30mb video as you read the review. Thanks to Mike Young who shot me fooling around with the Viking on the Ice Cream slope at the Bwlch. There's also a whole bunch of photos at the bottom of this page.

Writing reviews is way too much like hard work for my liking, so much so that I've become remarkably good at avoiding them. Every now and again though a plane comes along that people should know about - enter the Viking stage left.

The Viking comes from the same stable as the Sting range and is designed and built by Vaclav Vojtisek, one of the Czech Republic's top F3F pilots. There are some similarities with the Sting but there have also been several significant steps forward.

 

What's in the box?

What you get for your money is a one piece HN273 modified V tail, a two piece 3050 mm modified AH69 sectioned wing and a sheath nosed fuselage. Complementing this is a well engineered, light and tough carbon wing joiner, a comprehensive bag of horns, pushrods and linkages as well as some pre-shaped servo hatch covers. Each component itself is interesting for one reason or another.

The wing panels are acceptably light, have a good, tough finish and sport a perfect moulding join (i.e. no overlap). The ailerons and flaps are splendidly large and stiff, providing great manoeuvrability and excellent braking. The major factor though is that the wings really are immensely rigid. One of the secrets I can let out of the bag is that each panel has four ribs, which might not sound like rocket science but bridging the wing skins like that provides monumental torsional rigidity, which became obvious during DS and other general abuse.

I have a love and hate relationship with the V tail. It is strong, light and big enough but over recent years I've grown to love two piece tails and the transition back to one piece hasn't been without a fair share of self-inflicted trauma - more of which shortly.

The fuselage is a really nice unit. It is very tough, has a decent nose moment (reducing balancing weight), is very light at the extremities (it should turn like a cornered politician) and has enough room for all your bits and plenty of ballast. Of course there's no such thing as a free lunch and the downside is that to allow the control rods to clear the joiner, the radio installation and ballast access are inverted, which is uncomfortable but not a big deal.

 

Assembly

This is pretty standard moulded model fayre, so I'll just stick to the Viking specific issues, which'll leave more room for the flying report.

As far as the fuselage goes there's very little to look out for. I used the most excellent JR DS3781 servos, which at 15 mm wide just fit side by side. There is room to fit servos in line but fitting them side by side allows them to be further forward, which is good for the CG and for avoiding ballast that tries to liberate itself in a big nose in arrival. Speaking of which...

The method of ballast retention can vary depending on your taste and time available. I went for the easiest option; a thick pin going through the tube and the inner fuselage. We used to use the same arrangement back in the old pylon racing days and I do have concerns about ballast bursting through in an impact. I've no immediate plans to test this and hopefully the Viking should live an easier life than my pylon racers of old. There's plenty of room to engineer a more elaborate and sturdy arrangement but time, intelligence and dexterity were all against me.

I used a 4 x AA pack of 2200 mAh NiMHs, which left very little nose weight required. The importance of this can't be underestimated when it comes to turning performance.

The wing is a complete doddle. Indeed, it's the only wing where I've managed to completely bury the servos with no linkage showing whatsoever. As an aside, the servos in question were prototype digital Volz Wing Maxxs. I've just heard Michael Volz has bitten the bullet and put them into production, which is good news as they have proved extremely quick, powerful, precise, tight and robust. Go to www.volz-servos.com for more information.

The Viking wing is a delight to work with. Indeed it was the most pain free installation in a moulded wing I've ever done - even the linkages are provided. As a bonus the skin where the servo lives is already reinforced with extra carbon and there is a factory installed rib bridging the skins to make the perfect platform for flex free servo mounting.

The only decision when fitting out the wing is whether or not to use the supplied servo arm to pushrod connectors. On the face of it they seem like one of those ideas that's so good it can't possibly work or everyone would be doing it! Given it's a review model, and that the rest of the engineering is more than sound, and that they allow for a completely flush installation, I thought I'd have a little faith and give them a go.

Using the thickest Volz servo arms the screws easily attach themselves. A certain amount of subtlety is required, as a quarter turn either way is the difference between too tight or too much slop. Sounds scary but after some pretty rigorous flight testing it remains virtually slop free. Having said that, if I had the time, or if I was building another one, I think I would use ball links to achieve the same installation depth with absolutely no slop worries (no matter how unfounded!).

The only other thing you'll find when fitting out the wing is that you'll need to use a Dremel or similar to nibble a little material off the moulded horn mountings to get full movement without the clevises fouling.

For the wing to fuselage wiring I used the grey 5 pin Multiplex connectors. The green 6 pin versions also work well and if I were using free floating connectors I would have gone for those. I prefer spending a little extra time during construction to mount the wiring connectors so that they engage automatically when the wing is slid into place. I find the grey connectors slightly easier to mount but they don't have the built in pin protection that the green ones have. One final word on wiring the wing connectors; don't mess around with heat shrink, just test them and encase the wiring to connector block solder joints in epoxy.

 

Flying

Rather than the usual wordy story about the first flight, weather the sun was shining, the direction of the wind and what colour socks I was wearing, I've broken this down in to what you should really want to know, categorized by the different modes I use on my transmitter. It's based on many hours flight time in some very different conditions.

 

F3F - Strong Wind

The Viking is naturally pacey. You don't have to work at generating speed or managing momentum; it is all there in abundance and on tap. In that respect it reminds me of the legendary Masterpiece designed and built by Helmut Quabeck.

What the Viking has that I could never squeeze out of my Masterpiece is incredible turning performance. Whether your thing is big wide, collect the buzz, type turns or tight, gamble the buzz will probably happen, type turns the Viking is equally astounding.

Although the wing section isn't as thin as some around at the moment it is still surprisingly ballast neutral. If the wind is perpendicular to the hill there is little advantage in adding ballast even in winds of up to, say, 25 mph. Above that the choice is yours and probably depends a lot on your flying style (wide or tight) but the Viking isn't upset at either end of the scale.

When the wind is a bit cocked off the hill the Viking, like anything else I've flown, benefits from ballasting but probably less is needed than most of the competition.

The pace of the Viking and the positive and immediate way it responds to lift cannot be overstated. Every silver lining has a cloud and in this case it's the fact that the load on the pilot is slightly higher than with some other planes. Until you completely sort your set-up you'll find yourself making lots of small corrections to keep the Viking exactly where you want it.

Having more stick time on the extremely well mannered Pike Brio than anything else made the contrast very noticeable; at first I always felt one step behind the Viking. Several hours of stick time later, I've reached a set-up and CG that really suit me and I've got to know the plane enough so that it isn't an issue any more. I'd still say the pilot load is slightly increased over some of the competition but it's a small price to pay for the performance rewards.

Will the Viking win F3F competitions in strong conditions? Yes.

 

F3F - Light Wind

Going back a few years planes tended to be more suited to one set of conditions than another, largely because of the aerofoils of the day. We're much luckier now and the vast majority of commercially available F3F planes are equally capable in a large range of conditions. And this is certainly true of the Viking.

The Viking actually gets a few bonus points in light air as it is just as happy using the bank and yank technique as the full reversal. The only difference I make to my light air set-up is a little more differential, a tad more rudder to kick the tail around if needed and a little less elevator to reduce the chance of over excited thumbs provoking a flick.

Will the Viking win F3F competitions in light conditions? Yes.

 

Dynamic Soaring

Wow! We have a local DS spot that is kind of tetchy but when it works it really works. Purely in the name of testing I put the Viking through its paces and I have to say that this is the most rigid non-DS specific plane I have ever seen in a DS circuit. I had to tone the aileron movement right down as things were getting very twitchy at speeds I'd estimate to be not too far shy of 140 mph.

A couple of DS sessions left me grinning like an idiot and the wing servo to pushrod connectors still pretty much slop free.

 

Aerobatics

Double wow! The Viking has a real ace up its sleeve here. Using no more elevator throw than for anything else it'll do the most incredible flicks followed by the flattest spins that I have ever seen from an otherwise well behaved airframe. I'm not joking they really are a show stopper; you can hear jaws drop as it flings all its energy away in a most unnatural series of gyrations before settling into to a real sycamore seed flat spin.

The rest of the repertoire is pretty standard for moulded models; rolls - fast, slow and multipoint, loops - round, square or triangular, stall turns, cuban eights and figure Ms are all a doddle.

The Viking's natural energy retention sees it easily through the more energy sapping stuff like rolling circles and 8 balls even without ballast.

For general showing off, howling passes and absurd G pulling the Viking scores ten out of ten.

 

Thermal

This is where I had initial reservations. The Viking needs to be flown and that is not an ideal trait for a thermal soarer. A timely test came in an F3F competition when the wind disappeared altogether during my run. The plane before me landed out and no one launched after me. I completed the run and immediately headed straight out in the hope of finding some good air to get enough height to avoid the walk of shame.

There was nothing straight out, so I tacked right, by this time about two thirds of the way down the 600ft hill. Still nothing, so I pushed further out and headed back towards the left. The left wing lifted, worth a sniff, so I turned into it and was rewarded with enough lift to maintain altitude. Definitely worth hanging around there for a while to try and centre on it and hope it developed into something more positive, so I dialled in around 3 mm of full span camber.

This was a great examination of the Viking's handling, as I had to do around 10 or 15 full circles at very low speed carrying camber before the bubble let go and I was able to ride it back up to the landing zone. It was very rewarding as I had to work for it using all three axis but the times I got it wrong there was lots of warning and it was very easy to sort things out before it snapped into a spin.

So, not as easy as some but the performance is certainly there if you look for it and if you do get it wrong it'll forgive you. That'll do me for sure. Indeed, it would be interesting to see how the Viking performed in F3B.   

 

Crow Braking

Very well mannered and plenty of movement in those nice broad flaps allows for a steep, positive yet slow decents and makes catching relatively straightforward.

 

Summary

The Viking's performance is second to none. It's very, very fast, turns well and has no nasty surprises. If you flick it then it's your own fault, as it will have telegraphed a warning in plenty of time. Other than aerobatics, I've not had it flick on me yet but it's given me a few warnings here and there, so it is possible to take it to its limit with relative safety.

The strength of the airframe is equally impressive; I don't think I've flown a more rigid plane.

I do have three taste and fancy issues. I'm not a fan of two piece wings. They make a lot of sense - they are stronger, lighter and easier to make - it's just the physical size of the panels makes them clumsy to handle and transport. The performance is so good that you can't really argue with Vaclav's decision to go two piece. He's also made the skins really tough to combat any dings.

The V tail has been strengthened compared with the Sting and it is indeed a tough yet light component. Having said that I've become accustomed to two piece plug in tails and going back to a one piece affair has proved a challenge. Buy me a beer and I'll tell you about the self-inflicted agony at La Muela and the separate but even more painful camera bag incident... Again Vaclav has gone for the performance route - one piece means light - but personally the strength and transportability offered by a two piece tail represent a compromise that I'd be happy to make.

Finally the ballast retention arrangement could do with a little thought at the manufacturing stage - maybe a large diameter bolt like that on the Wizard Compact.

 

So what do I really think?

We don't have telemetry and wind tunnels, so choosing a plane is a very personal and subjective thing but, in my opinion, the Viking is one of the top three F3F models available at the moment. Out of the top three it's too close to call but if I had to pick a model based solely on flight performance the Viking makes a very good case for itself.

The Viking is available direct from Vaclav Vojtisek at VV Model, Sloupnice 156, 565 53 Sloupnice, Czech Republic or from selected dealers listed at www.f3x.cz. The price will vary depending on the dealer or and/or your location, so the best thing is to visit www.f3x.cz and contact your appointed dealer or Valclav for a price and details of availability.

Addendum - proof of the pudding...

I used the very same Viking to win the English Open F3f just days after writing this review. There's a quick report here.