Yesterday, I talked to the pilot who had the cylinder failure. He was at about 500' at the end of the crosswind leg, when he heard "a big bang" and the rpm dropped to 2100. He was towing a heavy two-seater (a DG-1000), but he had enough power to manage to get to a safe location, before waving-off the glider.
A and C,
The cylinder box is labelled "Superior Air Parts" and "Millenium Cylinders"
the fact that the same cylinder failed is not too surprising. This is likely to be the one which sees the most stress-causing conditions in operation.
Mechta, that makes sense.
PW Cooper,
A non-flying day today (Thursday) due to rain and low cloud, gave me a chance to look at the times for all our Scout tows this year (April to now). Our field elevation is 3700'. The density altitudes in April would have been not much more than 4000'. but on a typical soaring day from May onwards, with temperatures around 25° C, the density altitudes would be around 6000' and from the end of June onwards, we've had some very hot days (30° -35° C) with density altitudes of about 7000'.
We've done 454 tows this year ( 24 x 1000', 364 x 2000', 31 x 3000' and 35 x 4000'). I calculated the average tow time (normalized to 2000') for each tow-pilot shift in the log book. The normalization factors I used were 0.75, 1.0, 1.75 and 2.2 - our Scout definitely struggles during the upper part of a two-seater 4000' tow - the density altitude at release often exceeds 10,000'!
The minimum time was 7 minutes, the median time was 11 minutes, the average time was 12 minutes, and the maximum time was 20 minutes (on the hottest day so far).
Out of interest, I calculated average tow-times by pilot. Thirteen pilots have towed with the Scout this year. The minimum time is 10 minutes, the average time is 12 minutes and the maximum time is 14 minutes. Note that all these times are engine-start to engine-stop times, not wheels up to wheels down.
I think these are quite respectable results, considering the altitude we operate at and it is gratifying to see that the times achieved by our pilots are all consistently close to each other.
We haven't done enough tows with our 182 to get reliable statistics, because we are all still coming to terms with optimizing the tow performance. As one of our members, who is checking out pilots who haven't flown a CS prop before, said: "In the Scout, you fly the tailwheel, in the 182, you fly the engine!"
One more thing to consider is that our fuel is considerably cheaper than at Lasham! We pay about 74p per litre for 100 LL.
For comparison, 91 octane Mogas is about 54p per litre in Calgary.