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Tuesday, August 14, 2007


The maiden flight of Ventus ZS-VCX took place on Friday 10th August on the northwest slope

at Volksrust (Tamatieberg). The wind was northwesterly swinging westerly on occassion and blowing at +- 35kmph. The prototype Ventus no 1 flew well but was difficult to land (hard to slow down) and had underpowered servos for the job. Ventus number 2 (ZS-VCX) is a totally improved model in all respects and can be flown with real authority has a huge speed range and snappy turns on the dual full rates, landings are very gentle.

So less than a year after the maiden of no1 at Rosendal and only 12 flights on these big gliders I think that these flights convince me that this has to be some of the most exhilerating and rewarding results of my modelling career so far, I still plan to push the envelope a little futher.

Above is the data captured on Saterdays flight and after reviewing the flight video it all makes sense .
session 8 flight 2

starts at 0 with switch on in the car park the spikes at 3 mins are probably me blowing into the pitot tube with all my might, to see if it was working ,impressive I managed a 230km/h wind with a nasty chest cold, must have been all the performance enhancing drugs I was taking.
Flight starts at 8 mins with the altitude dropping down(purple) and airspeed (grey)starting to rise.
At minute 12 the vario indicated lift and I was well away from the slope and circled up in the thermal, to a height above the slope of 170 mtrs the rapid straight line decent saw the airspeed touch 150km/ph the grey spike as the altitude drops at about minute 13.

At 15 mins the glider dives down below the ridge to -20 mtrs speed at this time is 110km/hr

At minute 23 another strong thermal was indicated and I climbed to the max flight hight of 189mtrs, the decent was a spiral down hence the airspeed stayed below about 120 km/hr.
At minute 25 a series of higher speed low altitude passes were carried out for some close in video footage the speed remains in the 60 to 110 km/hr range and the aircraft is flown down into the valley on a few passes once descending to -32 mtrs.
At minute 33 the glider is climbed up to start the approach for landing at minute 35 after that the readings are of the airpeed while it was on the ground waiting to be retrieved.
The big servos pulled the battery down to 5.11 as a min and had a max voltage of 6.95 the average for the flight was 6.65volts this is indicated by the green line,(the battery pack is 5 cell NIMH 8000 mah) .
Its an awsome experience to fly this plane, but I have no plans to ever winch launch it.


glenglider said...

Congratulations on an excellent maiden flight, and thanks for sharing and explaining the vario graph. Your building skills and tenacity in getting things done truly amaze me Well done on yet another GBOGH project successfully completed.
Glen in Pinetown

Anonymous said...

Dear Glenglider,
Thanks for the kind words.....the cheque is in the mail.