Is it time to start my final glide?
There are 3 outcomes: save a few minutes, conservative, or land-out (this could be replaced by a low very slow save). Being conservative typically costs a few minutes. Strong high days more because you might stop turning 40 miles from home. Miss timing your glide and landing short of the field will cost you a lot of points, so it is probably best to error towards conservative. The most challenging final glides were at the SGP where being the first one home counted for a lot and being 10 seconds behind the leader could result in no points.
Last week I talked about setting out on a final glide that was below what the computers said I could make. I have my computer altitude set to 0ft above the finish line, so I put my safety margin into the MC setting. I typically have a MC=6, this is a comfortable fast glide, I continue to fly a slower setting but when I leave my last thermal I have a MC=6 made altitude wise. I continually fly a MC=2 (what I typically fly my MC setting to), then if the numbers are going well I increase to a MC=2.5, then MC=3, etc. So I flip back and forth, making sure I can make a MC=6 the entire time. I have 2 flight computers so I do not switch back and forth. Eventually finishing with enough energy to do what needs to be done after the finish.
One of the common mistakes is hanging onto a weak climb to get that MC=6. Many times it is best to leave that thermal and continue for an average or above-average climb to get to final glide. This is especially true if you are heading into the wind and your climb rate is effectively slower because you are drifting farther away from home. If it is a weak day the sink also might not be as bad and you could potentially head out on a MC=4, or even less. Just remember where your safety margins are.
Some reasons to have a more conservative final glide.
If the day is cycling and it might be a while before you are going to get another good climb. You might be willing to take your climb now because you will not be able to beat it ahead.
When you are connected with the clouds the thermals will feel very different then they do down low. It will become less organized and harder to align the thermals. Wind will help align the thermals. If your final glide is across the wind it is going to make it harder to get good air and beat your published glide. Remember how much altitude it cost you up high to cut across cloud streets, it will be the same down low.
If you had been flying with a hard-deck, you must remember that you put it in there because the thermals were difficult to work below that altitude. Which means once you get there on your final glide you are committed to that final glide. So you might consider that before heading off on a lower MC setting and expecting to use that height band to beat your glide.
Some reasons a more aggressive final glide might be possible.
Is the final glide into the wind or downwind? If there is a cloud street that you can align on final glide and not have to cross, that is much better. Even if the sky is not streeting, but looks good and looks like there are a lot of options for bouncing under the clouds it may be a good run. How has your flight been? Have you achieved a really good L/D for the flight?
How does the sky look? Does it look the same and you have been able to achieve 70:1 out of your LS-3? You could probably not have to take a thermal to get on final glide. You will probably run into the MC=6 just in cruise. I have one computer showing the MC=6 as I get closer to that portion of the task and see how quickly I am catching up to that. If I think I can catch it at my normal cruise speed then I keep flying straight.
This topic started at the request of Roy at SSA convention, he wanted me to talk about rain and final glides? Rain sucks, it is unpredictable, well normally sink is pretty certain, but how long, how much is never known. What might look like a small shower could end up being miles. I have found good thermals in rain and even long stretches of good air, but on a final glide that is not something I would be planning on. My two rules of thumb on rain are avoid and be high, preferably where it is below freezing and turns into snow and doesn't stick to the wing.
Banner Photo: Bob Rosa
Garret Willat holds a flight instructor rating with over 8000 hours in sailplanes. His parents have owned Sky Sailing Inc. since 1979. He started instructing the day after his 18th birthday. Since then, Garret has represented the US Junior team in 2003 and 2005. He graduated from Embry-Riddle with a bachelor's degree in Professional Aeronautics. Garret represented the US Open Class team in 2008 and 2010 and the Club Class team in 2014. Garret has won 3 US National Championships.