BMFA F3F Nationals 20-21st April at the Bwlch

[mark_r]

Just sharing a bit of analysis of the results and some more thoughts related to the ice cream slope flights on day 2. The competition had 3 distinct phases across the 2 days - round 1-5 on the wrecker had quite consistent air (the table clearly shows this looking at time spreads); we had a break for rain then another 3 rounds also in reasonably consistent air (table shows again), then we flew 5 rounds on the ice cream slope with more variability the wind steadily going off the course. The effect of the variability on day 2 is also clearly shown in the table - some folks suffered really badly whilst others gained quite significantly.

I've included some simple pictures to hopefully support the discussion around the wind direction setting for that slope too.

The table shows the min/max/spread for the rounds flown in the 2 lots of consistent air and the 2nd day variable air.

The rolling position chart is shows the results stabilising after the initial 4 rounds (1 discard kicking in), but then becoming more volatile on day 2.

 

The earth plots give a reasonable indication of why 45 deg wind deviation on the left side is unworkable for the slope, with the 20 deg limit being about right. The slope has a bearing of approx 319 deg, with the blanking high area opposite sitting at approx 290 deg. So at 30 deg deviation from the slope, the high point is at roughly the same elevation as the pits area. I think a reasonable clear direction (subjective I know) out from the slope has a bearing of approx 298 degrees, ie. that suggests anything beyond 18 deg deviation should be the limit. We need to bear in mind that the 45 deg and 20s limits assume a slope which has no blanking features, and clearly 20s with the wind being blanked simply won't work at all (as evidenced by a couple of flights and one complete loss of sight of the model below the slope).  My conclusion is that the limit applied on the day was about right and the evidence supports it. We should pick this topic (local rules) up as part of the broader F3F discussion due shortly.

 

 

 

 

[MikeE]

Interesting Mark, but analysis can be viewed many ways.

F3f will always have an element of chance. 

Even with a very quick view it can be seen that the last round, flown at a 20degree max, gave possibly the most random times, lots of breaks and then stopped the comp.

Conditions were still very flyable at that time.

Would it simply be better to fly more rounds to even out the conditions.

For many of the field perhaps a comp with more flying is a better than going home early.

To attract fliers we need to give them a good day out.

 

[mark_r]

F3f would be a bit boring and lacking in challenge and interest without variability - it's an integral part of whatever do.

The slope just needs to be able to work with the variability, which the ice cream slope can't when the wind is blanked on the left (Bruce lost sight of his model below the hill straight after we stopped - was very lucky to see it come out flying). The standard rules are absolutely fine (mostly) but assume the slope can work with 45 deg deviation.