As high as it gets

Twenty thousand one hundred and eighty feet. That is as high as it gets.

Yesterday the weather decided to cooperate and we where able to head up the Andes mountains again. For this trip we set up a portable oxygen system on the cargo area right behind the pilots seat.
The setup allowed for access to the oxygen regulator valve from the cabin (a bit ackwardly) so we could adjust the delivery when needed up in the air.

For the first part of the trip we kept the engine at 5200 rmp and  70kts. With these settings the climb went uneventful at about 500 fpm all the way to 9'000 feet.

Although the day was clear, we barely found any workable thermals on our way up, even considering that the rise of altitude on the area of the Andes where we fly is quite steep, so even we climbed at 500fpm, we always had terrain less than 2000 feet below us. By the time we reached 12'000 feet, we where barely 30 miles east from our airport which sits right next to the Pacific ocean.

September in Peru is the end of the winter on the coast, the seasons are not to defined here in the coastal areas, but today the temperature clearly was warmer that our previous flight where we reached 16'000 feet. Today the climb rate from 12'000 to 16'000 was barely 400fpm and it started lowering as we got above 16'000.

Once above 16'000 feet, I kept in close mind a couple of things that the guys at Pipistrel mentioned to me on the owners internet forum:

1. Watch your speed.  Most experienced pilots understand that because air at high altitude is thinner, the ram air hitting the pitot tube will feel "softer" so the indicated airspeed will show lower than the real speed. The neat thing with the instrument is that because of  the same thin air reason the wing of the plane also needs more speed to generate lift. In regular airplanes it seems to work out fine with instrument reporting the right speed to fly but, on a long laminar carbon fiber wing like the Sinus, another factor takes place: Flutter.

2. Slowly reduce the power setting as you reach altitudes above 18'000 as the barometric compensator on the Bing carburetor, no longer can reduce the fuel/air mixture going to the cylinder.

On the first point, we were *very* careful. Before the flight I had already read the manual *and*  the actual incident reports of cases where the wings of the sinus "came apart" in flight due to flutter on the wing induced by unawarely exceeding TAS on the plane.  At 16'000ft an indicated airspeed of 105kts is actually a true speed of 135kts (already exceding VNE!) and At 19'000 feet you only need to reach 100kts to exceed VNE.  Knowing the smoothness of the airfoils will prevent any "speed" noise that might alert about high speed, and know how fast the Sinus like to accelerate when asked to, We made a point to keep a close eye on the speed both on the mechanical instrument as on the Dynon flight computer.

On the second point, the guys at the board where right on. Close to 18'000 the engine felt a bit rougher a bit after the low CHT alert came up (Because of mixture too rich!) .. we lowered the power setting to 4300 and the engine started sounding good again.

With the power back, our climb rate took a big drop barely climbing more than 100fpm until we reached 19000 feet on the altimeter  (GPS reported 20'180)

So, 40 miles to the east of the sea, 19'000 feet high, the terrain directly below above 16'000 feet and further east the majestic Pariacaca Nevado with snow-caps going over 19'000 feet what did we do?

We turned off the engine, feather the prop and set up for a long glide back home.

What a great engine that Rotax 912 is..

Yesterday after almost 3 months without decent weather, the sun finally came out.

For a while we been interested on testing the performance of the engine at altitude, specially finding out how would it respond to a restart with the engine cold when above 14,000ft.

So, we packed our shades, glide computer, water, oxygen bottle and started a climb from sea level to 16,000 ft.

Our climb was uneventful. The engine at 4800 rpm,  speed 70kts. Climb rate was steady at about 500+ fpm, but after 15 minutes the oil temperature reached the end of the green line at 110C so we increased airspeed to 80kts while reducing power to 4300 rpm. With this new settings the engine oil slowly started cooling down. (the climb rate went town to 200 fpm)  Curious thing, everything else; water temp, oil pressure, EGT and CHT temps where all normal at all times.

I have to say that the oil temperature surprised me a bit. I've never seen the temperature go up like that on any other 912 equipped ultralights.  Usually it is almost impossible to get those engines to heat up!
I am guessing that on the sinus, the oil radiator has been shrunk to its minimum effective area for weight and space reasons. Still it was not much of a problem on a few minutes we resumed climb where outside temperatures help reduce further the heating issue. At 10'000 feet and above, the issue was pretty much gone. 

Eventually we reached 16'000 ft so, we slowed airspeed to 50kts and toured a little to let the engine cool down before turning it off. A few minutes latter, engine idle, magnetos off, un-necessary electrics off,  feathered propeller, trim to 55kts and enjoy the quiet woosh of the air along with spectacular views of the Andes below.

In general the air was stable with great visibility, very few thermals of weak lift. To the East we could clearly see snow caps on top of the 20,000+ ft Nevados topped by a thick layer of clouds another thousand feet above.

At this altitude our glide computer showed we needed 10:1 to reach our home base airport 40km to the West (at sea level) so we circled around looking for lift (with not much luck) on the regular places..

When we reached 14'000 feet we turned back on the Dynon engine computer which showed oil temperature had gone down to 20C. It was not as cold as we wished, but decided to test the restart anyway.
Un-feather prop, magnetos on, no choke, throttle idle and... it started flawlessly! it did not take a 1 second push on the starter to get it purring again.  I just love that trusty Rotax 912 engine. 

With that test over, still over 13'800 feet, we decided to just shut down again and glide our way back home. The tricycle sinus L/D  is listed at 27:1 , Our glide computer consistently showed above 24:1 at speeds higher than best glide so we toured around the area again, looking for good lift areas and enjoying the dramatic terrain below us.

A new piece of equipment for the flight was XCSoar gliding computer software running on a Google Nexus 5 android phone.  It is really superb, at all times we could see terrain, L/D required, distances, speeds, times everything!

The terrain feature is fantastic, showing a thick surrounding line on the map indicating "reachable" areas for our current speed and L/D. It also has a nice speed to fly feature, a vario with audio (The Nexus 5 has a barograph sensor) and all sorts of navigation aids for competition flying.  The actual device s my regular phone, it has great battery life (we had a spare charger) and the array of sensors is impressive.  To top it all, up there at over 3000 meters there was great signal reception, so I kept Tati  posted of our progress via whatsup chat messenger!

To resume XCSoar in few words:  All in all a wonderful piece of  software.

Next test, getting further East while climbing to 18'000 ft and return gliding,

 I will keep you posted!

Alx.



 

About the weather

Another week with out flying up the mountains.. The weather in Lima this time of the year is utterly depressing. Here we call that persistent grey cloud base that cover us for months  "panza de burro" or donkey's belly. not quite dark, not sunny, just a dim uniform white light from above.


To best use the time (and to beat the boredom of being stuck to the ground) we payed a visit to SENHAMI , the national weather agency in Peru.

The agency has a customer service (Servicio al consumidor) department where they welcomed us with  real interest on our project and loads of useful information about the weather conditions along our route
.

The image above comes from their website, and it shows the sad state (For soaring that is) of the coast of Peru this time of the year.

They where so helpful we ended spending more than an hour just talking about possible sites for soaring conditions in Peru and our experiences as free flight pilots with winds and thermals .

Something that surprised them, was hearing about the convergence of the Morro Solar  and how, in some lucky days we (paraglider pilots)  can get up to 1800 feet msl, by using the lift generated from the converging currents that meet back behind the landmark mountain in the area.

Finally, when I asked about RAOB or soundings, we learned of the limited resources they have to work with. For a territory the size of Peru, the only soundings done in the country are at Jorge Chavez Airport (SPIM).

In any case it was a great visit and a good resource for weather information in Peru.

It is interesting to note how many of the great scientific discoveries begin as myths

Central to the valley where we are flying is Cerro Condorcoto or Mount of the Condor. It is about 20 miles in the valley and at 8'000ft  it towers over it's neighbors. Much before we decided to do this expedition, we always heard a myth about eggs made of gold hidden at the top of the mountain. Last week while flying we saw round pirqas (inca stone walls) at the top. One wonders why would anyone climb an 8'000ft mostly rock mountain to build an animal pen?  Was it made by Incas to keep their Llamas or maybe later by the Spanish for goats?

I google'd around and found Empire of the Inca by Burt Cartwright, where he tells the story of  Pariacaca, the god of the sierra high places at the begining of the Inca civilization. He then mentions five golden eggs that appeared at the summit on mount Condorcoto, out of which hatched Pariacaca and his brothers, Pariacaca first act was to call down ruinous floods which carried away great destruction. (Now days we call those their quechua name "huaicos" or gigantic mudslides which occur every time the "El Niño" weather decides to show up.. like this year)

But before the mudslides..  Paricaca dressed as a beggar, visited the locals whom neglected him, except for a young girl who took pitty on him and gave him "Chicha" (A local alcholic brew made out of corn)  In gratitude, Pariacaca let her know about the great flood, so she and her children could escape.

The story is quite longer than that.  My point is to show the significance of the area to the Inca civilization and to share a nice tale about it.

We will make sure to be respectful to Pariacaca when we fly over his domains.. and we will do our best to drink some "Chicha" on his name.

Ps.
I just realized our glider happens to be called here  "El Condor" :)

Up, Up and away!

After a long while of cloudiness, the weather finally cooperated and gave us clear skies with 15 to 20 mph winds.

Tati and I decided to take advantage of the day and see what it would give us. It was good that Tati was available to come along as he had experience flying ridge lift on the west side of the mountains over Collique,  The old civil aviation airport in Lima. (This was back in the 80's and 90's  before most sport aviation collapsed in Peru).

As the image tracks show, we took of Lib Mandi's airport and headed towards the ocean so we could fly right in front of a 1000 ft wall facing directly into the ocean. We expected to catch some serious updrafts, but the wind was to south so they where not as powerful as we would have expected.

From there we headed straight into the valley, as usual at lower altitudes we found some lift but to small to work with our ship. 50kts is to fast and does not allow for tight 8 turns over the lift area. As we gained altitude we switch to the other side of the valley, as it looked that at altitude the wind was more westerly.

Judging by the intermittent orange areas ( indicating excess lift over our standard powered climb shown in yellow)  the wind somewhat aligned to valley creating lift on the right side.

Further up we switched to the left and found nothing but sink. (I did not logged winds aloft in this flight.. for next one I'll make sure to do it!)

At about 8'000ft next to cerro Condorcoto (Condor Mount) we zig zaged looking for lift with not much luck,  until we found some on the way to the the origins of the valley up at 11'750ft . From there, we stopped the engine and glided our way back while exploring both sides of the valley.

The Sinus manual on the tricycle configuration suggests 27:1 glide ratio.. in our experience, flying at 60kts, we consistently got 25+:1 , so much that we had to circle down as we left the valley because as usual the coast region was covered with cloud layer at about 2500ft .

More of the same..

This week we continued flying in the area looking for good lift.

First, with Juan as co-pilot,  we we enjoyed several good thermals while climbing power assisted to 8'000 ft. The first 5'000 feet the thermals where good, as the engine was almost idle, from there after not to much.

When we got to Cerro Condorcote we stopped the engine, feather prop and worked our way back while looking for potential thermal spots. We found some but not wide enough for the speed of the Sinus (50kts) but I am sure para-gliders would do quite well. ~ +2m/s.

The day after, we climbed again with Mauricio, with similar results but we changed the return path to be on the other side of the valley to see how it looked. It was about the same.

Both days the weather was quite sunny, no clouds (as always in summer) with very little wind. All in all, no surprises.

For the things we have to learn before we can do them, we learn by doing them

Coastal Lima is really not the best place for gliding. Even in the best of summer days, the most we get thermaling our paragliders over the mountains of Pachacamac is 3'000 ft. For thermals, we are cursed with a year long thermal inversion.

As I understand it, the high terrain in the Andes, where is mostly sunny, warm up the upper layers of the atmosphere while down below the cold ocean currents cool the lower areas resulting in a year round boring stable air. That is why in the central coast of Peru it hardly ever rains. (Several years ago during an El Niño year, it barely rained about 5cm , resulting in first page news and flooded roofs all over !)

For Paragliders, Miraflores with its 5km ridge facing the ocean winds is a great place to fly.

Almost every day, when the wind kicks over 14km/h you can take of from a park close by and cruise for hours on a smooth ride of laminar air along the ridge, literally a few meters from the buildings facing the ocean.

For sailplanes, our only choice in the coast, is to wait for one of those rare high winds days, and go for a wind facing mountain ridge on any of the valleys close by.









Back to the point of this post..  This month we been flying a lot!  Almost every week we continued exploring the area while climbing power assisted up the Chilca valley to 8'000ft then, cut the engine an return gliding.

Many days we found decent thermals but only to 3'000 feet, over that we only found short updrafts following the windward side of the mountains.

We recorded all our flights on several instruments that collected time coded data of altitude, wind, temperature, lift and sink to be used along GPS tracks for coded Google earth plots.

The image on the right, shows our GPS tracks color coded by lift strength, indicating our power assisted climb in yellow , then the various levels of sink (an a bit climb!) as we returned to base.




I will continue posting plots as we go along our journey.