Davinci Rhythm review

Davinci Rhythm: born to land

DaVinci is a brand new Korean paragliding brand. Let’s try their glider for school and accuracy: the Rhythm.

Design

When the first time you pick up a product of a company just entering the market – there is always some concern about the quality of the workmanship. But in the case of Rhythm you can relax. Yes, the design looks rather modest – it’s not Advance or Gin. But there is not the slightest claim to the quality of cut and tailoring. It was not possible to find the hand made markings on the wing – it means that the cut is very likely to be made by plotter, which is confirmed by very neat cut lines. Stitches and seals are also quite neat. I won’t be surprised if it will turn out that Rhythm came out from under the same sewing machines, on which the legendary Gin are sewn. In any case, DaVinci’s technologists and production workers honestly earn their rice with soy sauce, there’s nothing to complain about.

Only the risers could deserve some improvement. No, they are all right – but they are of a very simple make, without any frills, just like the second-third echelon brands do. The webbing is pretty wide (22 mm), the quality of Brummel hooks is very average, the pulleys of speed system have no bearings… The only sign of certain ambition of the Korean manufacturer are the decorative stripes with the manufacturer’s logo and accurate brakes with swivels. The line set is surprisingly minimalist: A2A’1B4C3. A three-row, which, in principle, is not necessary for the entry-level wing. The choice of materials does not disappoint: the thick and durable Dokdo cloth, thick sheated lines. It can be clearly seen that Rhythm is a workhorse, not a competition-winning “gun” . The same can be said for the shape of the wing. Modest, neat, low aspect ratio, large cell openings. The coloring, for my taste, is a bit lurid – but it’s rather a question of personal perception.

Take-off and ground handling

Classics! The Rhythm behaves exactly as it should behave. Inflation and rise up to the flight position is a leisurely, but very reliable. There is no need to “pull out” the wing with A-risers or, conversely, “slow down” it, preventing the overshoot. It is enough to somehow pull something – and after a couple of seconds, Rhythm will always be in flight position. Unfortunately, the weather did not allow me to practice ground handling with all my heart, but I had to master the wing in quite “combat” conditions – when starting from a limited area in a oblique gusty wind or almost at complete calm. And Rhythm did not disappoint, always safely and confidently going into flight position.

Performance

We are talking about the very fact that there is the entry level, “novice” wing, so everything is fine. And in some cases – even not bad. In a direct flight at trim speed, the Rhythm does not noticeably lose to the almost-training Ozone Buzz Z5 – provided that you arm yourself with a cocoon and try to fly as gently as possible. But any turn maneuver leads to a clear and very noticeable increase in the sink rate and drop of the glide. This is partly due to the shape of the Rhythm’s polar curve. Like the much older wings, the trim regime and the minimum sink regime for Rhythm are quite noticeably spaced – at least several kilometers per hour and not less than 20 centimeters of the stroke of the brakes. Therefore, when you are climbing in thermals, you have to “slow down” the device quite strongly, and attempts to work in thermals with small strokes of the brake do not lead to anything good. Similar behavior is typical for speed gliders and mini-wings, but Rhythm’s speeds are noticeably smaller, which greatly simplifies the flying.

Flight at bar

The Rhythm has a speed bar and it works. In practice, this is all that a pilot needs to know about the speed system of our examine. In fact, there’s a serious drop in glide from the very first centimeters of the speed bar travel which practically does not allow using the accelerator differently than to accelerate an already fast approach to the ground. Well, or just to train the accelerated flight. More precisely, Rhythm is good for getting used to some of the characteristic effects that arise in accelerated flight, for example, to a slight increase in the sharpness of the wing movements along the roll and pitch. I could not measure the speed increase – in every flight I did not have enough time for reliable averaging, the altitude was wasted too quickly. On subjective sensations, the speed gain is quite normal for EN A, something about 10 km/h. Interestingly, while flying at bar, the glider is perfectly controlled by the rear rows, not at all worse than the gliders by a pair of classes above.

Handling

Here everything becomes interesting. On the one hand, for small moves the brakes (within 5-10 cm) Rhythm does not react almost in any way, which, in principle, is normal and even good for an entry level wing. On the other hand, if you pretend to be a newbie and start pushing the brakes really hard – then Rhythm appears quite sane and even something pleasantly manageable. In combination with the above-mentioned features of the polar curve all this means that for thermalling on the Rhythm you need the good old style of piloting that arose long before the modern “do not prevent the wing from flying”. Rhythm needs help to soar, and it should be a very vigorous help. Weight to the maximum on one side of the harness, both brakes to the carabiners, the inner hand another 10-15 centimeters down – and the Rhythm reveals a quite decent, compact thermal turn. On such strongly clamped brakes, the Rhythm responds to the extra brake input quite well, allowing a fairly quick change in the radius of the spiral and the intensity of rotation. Even more interesting is the fact that at very large brake strokes (about 70-80%) the Rhythm does not become too sharp and does not tend to go into parachuting, but simply loses the glide. Perfect for precision landing!

The behavior of Rhythm at low speeds is generally worthy of taking out in a separate chapter. It seems that this glider was created primarily for flying at low speeds. For a long time I have not met a paraglider with such a sane, simple and understandable behavior in the left part of the polar. It is quite possible to stall the Rhythm – the full course of the brake is very large, but does not go beyond the physiological capabilities of a typical pilot. This applies both to the brake travel, and the brake loading near the stall. Somewhere after 50% of the brake stroke, the drop in glide becomes very noticeable, and further the glide smoothly decreases without the appearance of vibrations, local stalls on the part of the span and other effects characteristic for wings with higher a/r. Even on the 70-80% of the brakes Rhythm is simply flying – very slowly, calmly, with very low glide, while maintaining a sane handling. Even at large strokes the control does not become too sharp, the glider forgives even quite noticeable piloting errors, but it is surprisingly easy to control the glide angle. It’s also easy to correct the errors in the course and roll – the effectiveness of the highly clamped brakes is enough for that. As a result, you can safely go to the target with a height excess of a couple of meters – at the end of the approach this excess height can easily be removed by strongly clamped brakes, and you just go down in a smooth, quiet manner. The high dampening of the Rhythm very much helps when landing on accuracy in the bumpy air which tends to bring down the Rhythm from the trajectory given by the pilot.

Comfort and feedback

It’s not a glider, it’s rather a kind of a tank! It is clear that a glider with such a modest a.r. simply can not be sharp and uncomfortable – but Rhythm also has long rods in the leading edge, which provide this product of the Korean manufacturer with remarkable resistance to collapses. It is interesting that Rhythm very willingly rustles and crunches with cloth, warning about changes in loads to different parts of the wing – but all these rustling and crunching in practice means almost nothing to the pilot, because getting a real, “combat” collapse on the Rhythm is almost impossible. At dangerously small angles of attack, the rods willingly take a load on themselves, and Rhythm with honor comes out of tense situations. Rustling and crunching are not so useful, from my point of view, to search and center the thermals. Rhythm’s feedback is expressed primarily by changes in airspeed and a slightly less changes in loads on the hands. The harness gives very little useful information. As well as it is typical to a wing with low a.r., the Rhythm is absolutely not inclined “to wave with ears”, behaves very “monolithic” even in strong enough turbulence. Roll and pitch damping is at a high level even for the EN A level, although there are some special features. Falling out of the thermal, the Rhythm is inclined to suddenly “shoot” forward with an external half-wing, and it is desirable to slightly hold it with an external brake. But you can not do this – it still will not collapse.

Dynamics and energy retention

Normal average level for the school-training-accuracy wing. Having well tried and clearly knowing what and how to do, the pilot can quite achieve from the Rhythm wingovers and energetic spirals – but if you do not ask the wing about it very clearly and persistently, it will try hard to protect the pilot from sudden changes in the trajectory and unpleasant movements on roll and pitch.

Asymmetric collapse

Perfect! It’s not easy to provoke a collapse due to relatively high load on A riser. The collapse goes around 20-25% chordwise, and sturdy rods in the leading edge prevent the collapse from going further. In fact the typical collapse cannot fully develop, the half-wing remains partially inflated and reopens instantly after releasing the A riser. The trajectory deviation and surge are almost inexistent. The similar collapse and opening behavior is typical for well-known Cayenne5 from Skywalk.

Pre-stall during thermalling

Perfect. In general the entry level wings rarely have a pre-stall regime, but Rhythm has it, maybe because it is half entry-level, half accuracy wing. The regime develops in a smooth and predictable manner, the pilot has a couple of seconds to recognize the situation and to correct it. The surge angle during recovery is around mere 20 degrees, and it’s easy to conserve the thermal spiral during recovery and after.

Conclusion

The Rhythm is a very specific glider for a narrow range of application: entry-level school flights and accuracy. But when used as implied the Rhythm really excels. High dampening and calm reactions to turbulence and pilot input are good for beginners, and the brilliant ability to nicely controllable low-speed flight with very low glide is just what you need to win an accuracy competition. When you try to soar or to make some XC, the Rhythm shines much less. Even in EN A category, there are wings with better overall performance. But i’m happy to conclude that this Rhythm is so user-friendly that it can be used from the very first flight. The Rhythm strangely has lots in common with mini-wings: low a.r., specific polar curve, amazingly compact and nice turn at high brakes travel… but with much less speed compared to mini-wings which makes the Rhythm much, much safer. Okay, it’s hard to fly far with Rhythm, however You may land almost everywhere with minimal risk.

Pros

  • High passive safety
  • Calm and friendly behavior
  • High resistance to collapses
  • Unexpectedly good ability to turn at low speed
  • Very low glide at low speed, perfectly controllable low speed flight

Cons

  • Modest overall performance

I would like to express my gratitude to Rinat Sabitov (Russian DaVinci dealer) and to DaVinci Gliders for offering the Rhythm for testing.

Text: A.Tarasov / testfly.ru, R.Sabitov

Foto: I. Tarasova, A.Tarasov

The “danger” of certifications

Welcome in the tribe!

No guys, there is no danger in certifications, but there is a real danger in relying solely on them and nothing else.

This post is not about making some people angry, although I had my fair share of angry feedback, this is about making people aware that there is more out there beyond certifications and every kind of official tests done in paragliding for that matter. We need to understand that our beloved sport is still in it’s young stage, although, I recon it passed it’s childhood. Let’s analyze a bit the certifications and how they are performed. Firstly, it has to be said that those guys are really trying to cover as much as they can in terms of possible situations that might/will happen when using a paragliding kit (for flying that is). That being said, they only have a limited amount of kit at their disposal. And also, the tests do not take everything into consideration, as they simply cannot. It will be too expensive and time consuming.

First, let’s consider some of the aspects that the test, according with my knowledge anyway, do not take in consideration:

Front containers

The front containers are a critical part of your safety kit when the harness is not provided with it’s own reserve housing system. They ensure, or suppose to, that the reserve is deployed correctly. Is there any certification body that make sure this really happen? I do not know that, and I need your input to round up my knowledge if it is. Also, the front container is directly linked with the carabineers. Now, we all know, that one of the harness critical setting that have a direct impact on the wing behavior is the length between the risers. The possibility of adjustment is mandatory and the front container, along with a easy reserve deployment (but not too easy!!) needs to permit the waist harness adjustment to go all the way wide or narrow.

Cockpits

The cockpit nowadays is a must-to-have piece of kit for any “serious” flyer aiming for XC or already there. I really cannot count the number of times I’ve tried to adjust it’s position in flight to be able to see the screens. That sais all about the safety provided (or destroyed) by my cockpit. And it is made by a renowned company! Also, the cockpit is also attached by the carabineers or by their harness links (in my case). One needs to check the possibility of waist adjustment on the ground as well as in flight as we need to make sure the wing span have the correct setting according with the air we fly in.

Harnesses

As said before, the certification bodies have a limited amount of kit available to complete a wing with when tests are done. And in any case, the tests are done with a single harness for the lowest weight and with a single one for the highest weight. And that is it. Now, harnesses are very different, and their drag is directly influencing the wing behavior and performance. The elephant in the room, of course, is the pod harness. Although it can be certified (and in most of the cases is), by using it, the wing certification is voided. Whaaat? Yes, the pod harness modify the angle of attack, the speed, it’s lateral drag is higher and it’s inertia in case of twists is also much higher. Now, who can tell me that a high EN B for example, flown at the highest part of it’s weight range (still within certification, right?) with a pod harness, is not actually moved into the EN C standards? In fact, the common sense, if not the maths calculations too, are pointing towards this fact. They will behave like any other EN C wing, especially there, where most of the wings are getting their rank: asymmetrical accelerated tuck. But let’s see if we can identify more flaws of the tests. The position of the test pilots is quite upright when they are performing the tests. That’s sensible, and I really want them to continue to do that for their own safety. But how about flying the same wing with a very slim harness, well laid back as we saw all the pilots flying after they pass 30h of flying or so. Such a harness set up will not bring too much different results than a pod harness, especially if the tail is well designed. So, it is not just about pod harness after all. Not testing all available harnesses in the market (I am well aware it is a utopic thought) will not say much about how that wing will behave in all situations, including the maneuvers done during tests.

Another valid point is the use of solo harnesses for tandem. A lot of us are doing this, I know I am. The certification in this case is voided without any doubt. The easiest thing to say is: buy a new kit, but we all use our cars for example to go off road to reach a beach or other destination. We will never say: hold on guys, I am going to buy a brand new Defender and will be right back. Hold my beer.

Reserve parachutes

Sorry, what? The reserves are tested and every time they are deployed will behave the same as in tests if they are packed within an year or whatever period the manufacturer recommend. Yes, and yet, no. There are harnesses out there with their own reserve container. I still have one of those. Don’t you all think that the container is as important as the reserve itself? I do. And even with all in place and tested, I had a bitter experience when I was in the need to deploy the reserve. It simply did not want to come out. I had to use both hands to take it out whilst I was in a upside down position. And that was with a certified reverse harness that had it’s own reserve pocket under the seat. There are not that many in the market with this configuration so you can tell which one it was. 🙂 That tells me enough about the certifications. Is anyone testing the ability of the harness to easily open it’s reserve container for deployment? Especially after 8 months or so of sitting on it, waiting for the perfect thermal? No, is the short answer.

Chase cams

More and more popular, are the chase cams. The gear to mount your GoPro is even sold by renowned companies. The pictures/films are exceptional, out of this world, or better said, it potentially introduce our world to the general public. But let’s think about it. This is something that you tie of your wing (or lines) and not only that creates drag, you will probably say that the drag is small, but if you will fight with a strong headwind and step on your speed bar with all your life and hope, you will surely reconsider it, but also it brings a real danger when it comes with stalls. The wing will stop it’s forward movement, the cam will come forward towards you, and then, the wing will start falling. Chase cam system creates drag for stability, it is basically a small parachute, and in this case, it will go upwards into the wing. Chances are it will tangle with the lines, and the exit from stall is totally compromised. Now you need to throw the reserve, fitted in the harness container, not the one used in homologation and flatted by the countless times you sat on it. Sorry, just joking. Or did I? 🙂

Wings

Yes, the wings. There are many tests done for wings certifications, and all of them are absolutely relevant. Is just that… it’s not everything. And I am not talking here about the behavior of the wing at 5000m altitude (or 10k, Ewa Wiśnierska can tell us more about this). I am simply taking in considerations things that we all do, like wing overs, flying in really damp air or in rain/ clouds, etc. Although we are not allowed to fly in clouds, these things happen. I’ve landed once with my wing and lines soaked, water drops literally falling down from my kit after flying in a cloud. For sure, for the same certification, two wings from 2 different manufacturers will have different behaviors when wet. But the most important thing that is not tested are the very wings we are flying in real life. Even if you buy the wing brand new, it will be new for a while. A short while. Almost all it’s life it will be an old wing at different stages of wear. I am currently flying a Delta 2 from 2013. Who can tell me what EN/DHV my wing have now? The canopy deforms with time, the lines are shrinking at different lengths, the porosity is lower, the UV eats the fabric’s strength, and so on. I will really want to see a test for each year of the wing’s life until the release of a new model at least. Following the example above with the cars, the MOT is a test, a re-certification if you want, that is done for the whole lifetime of the car. And the tests are always the same, not in line with the latest norms, but the ones that the manufacturer declared at the date the car was launched. This will be a safe thing to do with the paragliders as well, don’t you thing?

Conclusion

I could go on with more issues, most of them minor ones at first glance, but let’s stop here as I believe I’ve showed enough to understand that hiding under the certifications, tests, licenses, and all sort of paperwork in our sport is a big mistake. One cannot control everything, and that will be the case for long time from now on. We all know the perfect example with the Carrera which in fact is a EN C wing but passed the EN B certification (thank God that the manufacturer is a really serious one and clearly stated the pilot type this wing is aimed to). And this is just the tip of the iceberg, I’ve flown an Apco Presta back in the days with really big surprises in the air; this one was another wolf in a sheep skin. So, what is left for us to do in order to keep us safe? Is to learn from people that used a certain equipment, what they said, how it feels, etc. We need to do our own tests, to see if we can understand the kit we use, aiming to be one with it. They say that the best pilot is not the one using the safest (by certifications) and/or more performing equipment, but the one that is one with his or her equipment. The pilot that is able to perfectly set the gear for it’s own needs, and in the same time able to adjust himself to the gear’s “needs” and limitations, will be the safest and most performing pilot. Test the gear before buying, read all that was written about it, and by all means, use the test reports as a guidance, but do not rely just on them.

Safety above all. Fly safe!

Going light

Hi y’all! Let’s discuss a bit about reducing the weight of our equipment. Many of us jump immediately and search for a light version of the desired wing i.e. buying an Alpina instead of Delta. Here are the weight differences for the ML size: Alpina 2 ML – 4.5kg vs Delta 3 ML – 5.44 kg. The problem is, that the kilo shaved off in the wing weight comes with a pretty hefty trade off: the wing’s life time. Are we willing/able to change so often the wings? Are we ok with the price difference? Well, the answer should always be: what do I get for it? You get a lighter wing to carry, it’s true, but how often do you carry your backpack more than 30 mins? You get a slightly better flying behaviour due to the lower weight of the wing, this is just something found by the users of both variants. But you also get a thinner fabric which is more prone to rippig off when taking off in high grass with God knows what other nasty thorns or pointy rocks are hiding in there. You get a fabric that will deteriorate much faster from UV, and finally you get a wing that can potentially break easily in high energy manoeuvres or recoveries – I know, you will say they are tested, and they indeed are, but when they are brand new, that is. No producer is publishing the results of same EN tests done when brand new, for old wings, although this will be a good idea.

Now, all that being said, there are people out there that are hiking and flying. They are aware of the trade off, but they still need the lighter and safest wing possible. But those chaps are not limiting themselves just at the weight of the wing itself, they are rigorously checking everything: reserve, harness, clothes, electronics, food, water, and all the other bits and bobs we carry around in our kit. Before considering investing fortunes in a new wing, let’s take a look at all the sh*t we keep carrying. We can consider a lighter rucksack, an ultralight reserve to replace the already old solid block of concrete, replacing the harness seat with a carbon one, but those are the obvious ones. Personally, I found myself one day looking at the 2L bottle of water I brought on the slope (although my camel back is 1L only), the extra clothing that basically double the one I wore already (so it couldn’t be used anyway), the GPS spare batteries (although I really do not see myself changing the batteries while flying), the second pair of lighter gloves, the batteries packs of my heated gloves (not using the heating in summer), the extra radio for the eventually friend that eventually (pun intended) forgot his, another 1/2L bottle of water half empty (or better said half full) hiding in my cockpit, two protein bars (never use them – when I am going for distance I usually land and choose a nice pub to wait for the missus), and so on. I am carrying them so I won’t forget them at home and then need them on the hill. That is fine, but why don’t we make an extra bag with all the extra stuff we “might” need and take them in the car with us, but not in the backpack? We can call it the plan B bag, or whatever and if you will weight it, you will discover that it matches easily the weight difference between the light and normal versions of same wing. That, on top of the advices on lighter carry bag, harness seat, lighter reserve, will reduce your weight-on-shoulders with at least 2-3kg if not better. Now go ahead and spread all your kit in the middle of your living room for the pure happiness of your partner who just wants to watch the telly! 🙂

Later edit: When was the last time you cleaned you wing? Once, I found trapped inside apart from the usual dried weeds and insects, a good sized rock. 😉