Yes Foxmoth, that's what I'm saying. To get 3 miles / 1000ft you would need a decent rate of 300ft/min and it is MUCH more than that - it's more like 800ft/min. One flying school reckons 1.4 miles / 1000 ft which I wouldn't disagree with, which means 7000ft will get you about 10 miles. I suppose the best way to get the exact figures is to give it a go. Next time you're up, put the engine to idle, trim for the best glide angle and see how long it takes to go down 1000 ft.
Whenever I go across the Channel (and I've done both the short hop to Cap Gris-Nez and the long one from Alderney) or over to Ireland I always carry a liferaft.
Avard, I can't remember the formula for the range of VHF radio with height (it in the Thom IMC book), but it's something like 1.2 * sqrt(height in feet/20), which works out at about 10 miles at 1000 ft.
Jayemm, if you do decide to go the Cherbourg route be aware of the restricted zones (and check this yourself using an official source, don't rely on me!). This is from the Flyer site.
France eases up on Cap de la Hague
Last October we reported that the French authorities had instigated a prohibited area and a restricted area around the Cap de la Hague nuclear processing plant on the Cherbourg peninsula.
Recently, the authorities have eased the regulations surrounding the restricted area. Previously entry into the area had required 48 hour notice and was available only to aircraft based in Guernsey, Alderney or Cherbourg. Now the restricted area is available to all aircraft, subject to flightplan filing with NOTAMed addresses and "DIC LH22" in item 18, one hour's prior notice and compulsory radio contact ten minutes before entry into with Cabillaud Radar (which is now on 127.57, previously 122.15).
Infringing either the restricted area (30km radius from Cap de la Hague, up to 5000ft) or prohibited area (10km radius based on Cap de la Hague, up to FL70) is regarded as a serious offence by the authorities, who threaten heavy penalties, imprisonment and forfeiture of the aircraft.
Please check the NOTAMs before flying, and make sure that you're legal.