Thursday, May 1st, 2008

My high tow to the North

Just before I launched last Saturday in my Nimbus 2, Pete Siddal who was towing advised me that a band of rain was only 15mins away approaching from the west and that there was no lift out to the west. We had a good look at the sky, which was 8/8 cloud and there was some dying Cu out to the north on the other side of the highway. The wind was 15 to 20kts from the west on the ground and about 25kts up top.
So the options were to take a normal tow out to the west into wind and find nothing and land or take a risk with a long tow out to the north with the hope of finding some lift.

So we opted for the 2nd option and headed on a NNW track from 26 to ensure I had safe height to get back in case of a rope break. It was a very smooth tow as we headed up wind of the dying Cu which was directly North of the airfield. Approaching 3,000ft we changed track to the NNE heading directly for the Cu. We arrived at the Southern edge of the Cu at 4,000ft with the base of the Cu at around 4,500ft and it was time to get off and go explore.

I headed North under the Cu and found less than 1/2kt of lift and with the drift it was pointless staying here as I did not want to drift downwind of the airfield. I left heading WSW back into wind for a few kms and found a 2kt thermal which gave me an opportunity to access the weather approaching. The squall line approaching was angled NNW with the bottom edge just approaching the airfield, with it extending out around 25kms. I was about 15kms to the NNW of the airfield and between me the squall line I could see dust being blown off the paddocks below on a line abeam me and continuing out to the north.

Robbo in the rainThis looked promising to attempt to run the front of the squall line NNW to fly around the top of the rain and in behind it without getting wet. The dilemma I had was assessing the what if as I did not want to find myself below final glide height back to get back to the airfield or getting stuck downwind. Not a day to be outlanding in a paddock with strong wind and rain. I also had to take into account my final glide height being at worst case through rain and with a 90 degree cross wind component.

Lots to think about and access in a short period of time, thank god for WinPilot and a few turns of the McCready and bugs knobs and I had a glide setup for rain conditions. My nimbus with its big wings does not like getting wet with the 48 to 1 glide ratio dropping back to what feels like about 30 to 1.

I was at 3,500ft and headed toward the dust and it wasn’t long before I was in 6 to 7kts directly north of the airfield heading on a NNW track and climbing. Approaching 5,500ft I increased my speed from 55kts to 70kts and to 80kts at 6,000ft and 90kts at 6,500ft as I reached the end of the lift. I continued NNW for a little further but the cloud to the west and NW of me was lower than me. I was 23kms North of the airfield and to get around the cloud I would have to go another 5 to 10km further North with no way of knowing what was behind it to the west.

Robbo in the rain 2Looking back to the airfield which I could not see for the cloud and the rain. See photo’s of what I could see to the south of the airfield. The final glide was predicting 1800ft to arrive back at the airfield flying at 80kts in rain so this was the best option. I headed directly south flying at 90kts to keep out of the cloud through light rain then turned SW and into the rain which was rather heavy. I wanted to get through the rain as quickly as possible so kept the speed at 90kts as I watched the Altimeter wind down at a great rate of knots.

I was heading for a light patch of clear air 5kms NW of the airfield and as I approached, the airfield came into view popping out of the rain at 2,500ft. It felt much better to have a normal glide ratio again as the wings dried in the clear smooth air. Looking out to the west there was another very large band of rain approaching and with no lift around and no way of being able to dodge the next one so I decided to head in and land before it started raining again on the airfield.
It was at this point that I received a radio call from the pie cart to ask if I was still flying – I assume they hadn’t thought I had outlanded.

Flying back to the airfield at Vne for the obligatory low level finish I hit the rain again on the Northern boundary to the airfield for a finish and circuit in the rain.

Overall a 44min flight from a 4,000ft tow instead of what would have been a 15min flight off a 2000ft tow.

Peter Robinson

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