Unless I am mistaken, which I usually am, the problem is similar to that of things like the Quickie...
You get a high speed take-off and although you get a reasonably rate of climb in fps, you also get a very shallow angle, so things like trees at the end of the strip become much more of a problem than they would with a slower moving aircraft which has a steeper climb angle. I do wonder sometimes if we are not like natives being bought off with beads and mirrors. Internal combustion engines, like democracy, are pretty awful things, but until something better turns up..... Most IC powered SLGs can get up to 2000' for about 2 litres of fuel. Most modern ones have a climd of 800 fpm or thereabouts at <50kts with a steep climb angle. And although there are millions of moving parts in the engine. they're all the type of part that a chap with a lathe in the back room can turn up in an hour or so. You can't say that about the jets, whatever their advantages. D On 31/05/2010, Mike Borgelt <[email protected]> wrote: > At 11:46 PM 30/05/2010, you wrote: >>pretty long take-off run; high density altitude? >>PeterS > > No different from a prop which also loses thrust at high density altitude. > An initial slow but constant acceleration doesn't actually increase > the length of the takeoff roll compared to a higher initial > accleration which decreases as you go faster. You are covering lots > of ground while going faster so that's where you want the higher > relative acceleration. For a 400Kg glider with TOP (75Kg initial > thrust) vs a 400 Kg glider with 68 Kg jets the thrust crossover is at > about 10 knots. With 56Kg thrust it is at around 21 knots. > > Mike > Borgelt Instruments - manufacturers of quality soaring instruments since > 1978 > phone Int'l + 61 746 355784 > fax Int'l + 61 746 358796 > cellphone Int'l + 61 428 355784 > > email: [email protected] > website: www.borgeltinstruments.com > > _______________________________________________ > Aus-soaring mailing list > [email protected] > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring > _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
