XWind Dragon

[Hub-Bar]

I had a nasty experience and would like to share, out of humility – maybe it can be of use to someone some day. On the 4th January Andre Gruindelingh, my partner in the Bantam, and I decided to have breakfast at FASH flying from Pearly Beach airstrip – he in the Bantam and I in the RAF. We checked the weather forecast and mild SW wind 10 kts max was forecast throughout the day. We were happy with that and departed Pearly around 07h30. Had a great flight coastwise around Hermanus, over Arabella, Grabouw, Sir Lowrey’s Pass and descended to 1500ft over Somerset West. As we rounded the Helderberg, we ran into a stiff NNW headwind and landed at FASH about 09h00. Had a cup of coffee and a great breakfast and departed back to Pearly about 10h30. The wind at FASH remained fairly fresh NNW and slacked from time to time. No indication of picking up. We knew we were in for some turbulence after Sir Lowrey’s but expected mostly lift on approach over the pass. Nice tailwind from FASH to Helderberg and then things smoothed out. The expected lift did not materialise and conditions seemed the same as was on inbound. I crossed the ridge at 2500ft and within 500m over, was knocked for a six by a SW wind that came howling over the Steenbras dam (my right-hand side). No option but to turn the RAF’s nose into wind and descend – looking for a spot to put her down. At about 100ft AGL I managed to start moving with awkward crablike motion in the direction of Grabouw. Halfway to Grabouw it got better – turbulence still very bad but manageable and the SW Xwind remained an issue. At this stage Andre, who was a couple of miles behind me, passed me and he was ok at 3000ft. I started climbing for crossing the ridge at Arabella. Close to the ridge it became clear that the SW Xwind was just too fierce for me and the gyro (SW is along the ridge and it felt like I was entering a jet stream and losing control) and after two attempts I considered landing back at Grabouw and call it a day. At this stage Andre was already over and holding on the eastern side of Arabella, waiting for me. I then decided to give Houwhoek pass a go at low level and if that doesn’t work, to turn back and land at Grabouw. I knew that at low level the turbulence was going to be worse but hoped the wind speed would be less. I was right about the turbulence, but wrong about the wind speed – it was as bad or worse than higher up at the ridge. The opportunity to turn back was lost immediately. The only way was forward or plonk it down. I kept heading by just about full left rudder and forcing the stick into wind, totally cross controlled. It felt as if I was inclined 30 degrees and the piece of wool on my windshield was stiff at the horizontal, the wind pumping through the cabin. This was the only way I could manage to keep some form of control. I realised that I was at the limits and was afraid of running out of rudder authority or cyclic control so I hugged the ground, prepared to plonk it if I could not hold her any longer. Can’t say if hugging the ground was by choice or by default? Anyway, it felt better, the plonking in mind. I was grunting with the effort of forcing the stick into wind and the gyro was all over the show at the mercy of the wind and turbulence. This kept up till halfway between Botriver and Hawston before things got more controllable. I wish I could apologise to anyone on the ground who witnessed this spectacle – it couldn’t have looked good. And to top it off, I made an extremely crap landing back at Pearly. I couldn’t write the logbook back at the hangar, only managed a scrawl and my right arm and shoulder was stiff for the next two days. All I can say is that it was by the Grace of God only that I stayed out of the headlines. I made a number of mistakes and learned the ageing way – not advisable. I always thought that the maximum crosswind spec for an aircraft pertained only to landing capability….. Now I know that it can literally blow you out of the sky. Another very interesting observation is with regard to the Bantam. I have always maintained that with the Bantam I can fly in any condition that the gyro can fly in – and this is true as far as my experience goes. Now I also know that in the air the Bantam outperforms my gyro in extreme Xwind conditions – somehow I suspect this to be relevant to all types of gyro. The idea is not to start a debate, but to tell all the folks that tell other people that the gyro is the aircraft to be in when the weather goes south, to think again – this may not be true in all situations and may create a false sense of security with some folks and fools like me. Today is the 7th and still raining my way, but already I am itching to get under the rotor blades again – crazy stuff…..

[Vertical Tango]

Hub-Bar, sorry to hear about this adventure ! Mountain flying is a skill on its own that you guys in the cape are good at it.
In your story, I am not understanding your need to x-control in cruise flight regardless where the wind comes from. I am probably missing a point. Why not crab with neutral controls ? When x-control is applied, the performance degrades aerodynamically. Please explain what I missed, we want to learn from your experience.

[Learjet]

Of all the prevailing winds in the Cape - I find the south wester to be the worst one for mountain flying. The reason for this is probably threefold:

1. The south easter shows its presence with white table cloths over the table mountain and hottentots holland ranges. You see it - you knows it's blowing a gale over those mountains tops.
2. The north wester brings bad weather. We Capies know that. And the old fisherman will tell you that when that initial little "cap" of cloud" starts to shroud the top Lions Head, the front is approaching and rain is only a matter of hours away.
3. But the south wester is a bugger. No early tell-tail mountain cloud signs to give you some visual cues as to what's happening up in the ridges. And it blows along the mountain ranges causing long turbulent rotors that wash across the transit passes and plateaus. It's like water trying to slosh crossways over a corrugated iron roof. Not a mountain flying friendly wind direction.

A gyro has a significantly higher wing-loading than an LSA so in theory the gyro should handle turbulence a lot better than the Bantam? Perhaps the extra few thousand feet altitude to where the bantam was flying would have presented a less turbulent option and out of the rotors washing across the escarpment?

Glad you came thru ok. We can all learn from this "sneaky south wester" experience.

[Hub-Bar]

Vertical Tango, with regard to your comment about us Capies being good at mountain flying – I would rather think it is a matter of with time we get better at avoidance. I do not have a ready answer to your question but I can tell you how it felt. It felt like the xwind was ‘getting under my wing’ and trying to flip me over to the other side. Therefore on the first encounter I put my nose into the wind but that was a short term solution as I could not continue for long in that direction (from frying pan into the fire). I think that as soon as you get a significant xwind flow over your teetering rotor wing, things start to go doubly wobbly. Add to that significant turbulence and the plot against you thickens dramatically. I usually crab in xwind conditions, but there is an early limit to the crab angle/wind speed where I feel comfortably in control. I have often crabbed the Bantam very comfortably at around 60 degrees in strong wind – even to the point of taking my hand off the stick and with enough rudder to stay on the ball, enjoy this peculiar sensation of flying sideways. I think the fat dihedral on the Bantam wing causes it to sort itself out – the rotor wing on the gyro does not sort itself out, it wants to be controlled by you. Dave, I think that explains the Bantam behaviour? In forcing the stick into wind, I could feel the spot where the effect (trying to roll me over) of the xwind was negated and I was consciously fighting to control to this spot. I think that because the nose was pointing in the direction I was going, my subconscious could manage as best as it could the control of pitch, yaw and whatever was going on in that direction as this is the normal response mode. I have no idea of how strong the xwind was that morning, but is was definitely way outside my and the gyro’s envelope and I hope I will never ever find myself there again. It would be interesting if someone could shed some scientific light on what happens dynamically if significant xwind is introduced to the rotor disc? So, in conclusion VT, I did not reason the xcontrol at the time, it just happened and it saved my bacon.

[FO Gyro]

Hi Francois, thanks for sharing your experience. I'm trying to make sense of what you are trying to say. Unless you are landing, there is no crosswind limit when you are in the air, as you are moving within a parcel of air that is moving.

A gyro is no more likely to "roll over" in a strong crosswind (in the cruise) than with no wind. What you are feeling is the downwind drift, and the feeling that you are somehow sliding or skidding towards the downwind side. Flying cross controlled would make things worse and would impair your performance dramatically. Your controls should be in the neutral position. No wonder your arms were so sore.

What I would suggest is flying in a very strong South Easter, and practice crabbing at 90 degrees to the wind, so make peace flying in these conditions with the controls neutral.

I have never flown a RAF before, and can only comment on a Magni or a MT-03, but I can tell you anyday, that I would much rather be in a gyro than in a LSA type aircraft in turbulence or strong winds. I think the cross control factors as highlighted above would have led to a sense of panic, which should not happen in a gyro.

Does this make sense what I'm saying, or am I missing something?

[mikemat]

Hi Francois. Phew!!! Glad all is well though. Although I've been out of gyro flying for some time now, from my limited experience I'm inclined to think that we can become quite anal about avoiding crabbing in flight, probably because it looks awkward and messy, and can give you a cricked neck if you do it for too long! Needless to say, the need for cross controls in crosswind situations becomes vital at landing, and having experienced landing when you have no more 'play' and are therefore cross-controlled to the max can be pretty scary. I hope you are otherwise well!

[Hub-Bar]

Thanks for your input Glen - appreciated. What you say makes sense and I will have to sort this demon out by doing some work in strong wind. I will need to convince myself/make very sure that my ‘roll over feeling’ is indeed merely a downwind sliding or skidding as you suggest. That will take a lot of weight off my chest. Obviously the xcontrol is not the answer although it served my purpose in the low level confines of the pass. Luckily I did not hit the endstops. Mike – good to see that you are still with us, I will try to be less anal about the crabbing!!

[saraf]

Hi Francois

You are always welcome to come for some crosswind training again.

I will get yolande to email you the dates that i will be in Saldanna to provide training for those whom are interested.

Regards
Eben Jnr

[Yolande]

Francois,

Eben will be in Saldanha, based at the Airport from 28 Feb - 06 March 2014, 9 - 23 August, 3 -18 October, 1 - 8 November. Should you be interested, you can send me an email yolande@rafsa.co.za so that we can schedule training for any of these dates.

Regards
Yolandé

[Hub-Bar]

Yesterday there was a fresh Westerly wind blowing here and I used the opportunity to try to work at my issue. According to my GPS the wind was 13kts and it was gusty and turbulent – normal for W and SW winds in our area. Not the weather I normally take off in to have fun. Glen, I put your theory to test and it makes sense. The slightest downwind bank (being at right angles to the wind), causes instant downwind acceleration and it has a vertically down component as well – hence the ‘roll over feeling’. Anyway, I played around with gradual crabbing from into wind to downwind both to left and right and I am happy with that. On a next session I will explore the ‘roll over feeling’ and see where it takes me. Thanks again for the advice. Most of us normally only fly in good weather conditions but now and again we get caught in more difficult situations which points out our shortcomings and we learn from that. Ebie, thanks for the offer – recurrent training is always a good idea. I would love to fly with you in some awkward weather but to get all the ingredients together for such a session is going to be difficult. Let’s see what happens closer to the time. Regards to all.