This bout of hot weather will adversely affect the performance of our tugs. Most of you will know the following but we all need reminding from time to time, so here goes.
Engine: This will run hotter than usual, CHTs will be high and more importantly the oil temperature will be close to and potentially in the caution zone. A sequence of continuous tows will see the oil temperature getting hotter with each tow. All you can do here is to stop and let the oil cool down. A stop, wait and start procedure may be required. If you do stop, let the engine cool down by leaving it running for a minute or so at 1000/1100 rpm, after completing a tow (into wind will help if it’s possible). It may also be necessary to curtail higher tows when critical temperatures are reached ie; wave off the glider before it gets too hot. Please forewarn the glider pilot that this might happen.
CA demonstrates these characteristics seemingly before the others but you can be sure that the other tugs will all be suffering the same way.
You should also ensure that there is a good amount of oil present at the beginning of operations. Ideally more than 7 but less than 7.5, this will slow the rate at which the oil temperature creeps up and obviously be beneficial to the engine.
Performance: It should be obvious that the aircraft will perform poorly, slow off the ground and a slow rate of climb in the hot ambient air. Be careful before doing downwind take-offs or even no wind take-offs, beware of the heavy glider too. These elements will only exacerbate an already compromised tow operation.
Pilots: Keep hydrated and guard against the effect of the sun on you. Don’t be afraid to stop if it’s getting the better of you. The aircraft would if it could talk.