dcc's Lightning adventure
- Thread starter dcc
- Start date
apollosmith
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Yep. Now that I only have one leg left, I think I've figured out a pretty good ascent and descent plan. With a bit more calculation, I'm sure I could figure out an optimal altitude (not accounting for winds) for each flight too, but I've just been winging it.
I take off in a shallow climb to about 240 knots indicated, then throw on the WEP and climb fast enough to maintain that speed for 4 minutes. I then continue a shallow climb to altitude. Once level at altitude, I use one minute of WEP for a nice boost to get me quickly to cruise speed. I think using WEP through the thick part of the atmosphere and to get to speed once level seems to give the best bang for the buck. With more time, I'd play around with some different ascent plans to see which works best, but this seems to work pretty well (when I don't overrun the WEP time).
For descent, once I have a rough guesstimation as to where the airport is (Google Earth helps a lot), I have a spot just a bit above the bottom of the wind screen (maybe an inch of monitor space above the dash in 2D cockpit) where I target and begin my descent when the supposed airport location hits that spot. I'm usually too fast to at ~4000+fpm descents to just a few miles from the airport. Even without the dive flaps "Marge" puts the brakes on pretty quickly.
Anyway, I'd be real interested to know what you're doing differently. I'm a numbers geek and love squeezing every ounce of time and efficiency out of these birds. I'm about to try the long, last leg, but will probably try a dry run first to make sure I can do it in one hop with the tanks.
I absolutely love your P-38s and have many, many hours flying them - particularly the -M model in the last many RTWs. Thanks!
What I did was start my descent a little after I acquired my beacon signals. I read somewhere that happens at about 75nm out, maybe I should confirm that. So, dividing 75nm by my ground speed gives me a close time out from landing. Dividing my cruising altitude above the surface by that time gives me a good descent rate to pattern altitude. And of course I studied my maps before the flight to know what landmarks to look for to find the runway. Pretty simple when you think about it.
Hope that helps.
dcc
P-38 nut
For the RTW I typically climb out at 2000 ft/min till about 12k then 1600 ft/min for the rest. Then at about 23k I put on WEP for 4 minutes to get up to max speed as I level off at 25k. (I never use WEP the full 5 minutes, because I've had it go out on my in less than 5, but never less than 4) For descent I usually start off at 1000 ft/min, pick up some speed and start to lose some altititude. Then as the air gets thicker I increase the descent rate to maintain about the same GS, eventually to about 3000 ft/min. About 10 nm out I'll go into approach mode, reduce thrust, maneuver flaps at 300mph indicated, 1/4 flaps by 250mph idicated, gear down at 180mph indicated, full flaps at 150mph indicated , come over the fence at 100-110 then flare at 80-90. I can do the approach sequence almost in my sleep, as I've got literally thousands of hours on my P-38s Bad Wx usually wakes me up a bit, though.
But with this race, I've been using my normal climb and approach methods, but because I'm flying purely visual and not getting up to normal cruising alt, I've just been winging it as to when to start descent -- when I start to recognize forms and objects, or when my dead-reconing calculation tells me I'm coming up on the target. Fortunately the wx has not been too bad, so I haven't been blown off course very much. Last night my timing was much better, so I think I'm getting a better feel for when to start going down just based on visual cues and my stopwatch.
Bad Wx usually wakes me up a bit, though.But with this race, I've been using my normal climb and approach methods, but because I'm flying purely visual and not getting up to normal cruising alt, I've just been winging it as to when to start descent -- when I start to recognize forms and objects, or when my dead-reconing calculation tells me I'm coming up on the target. Fortunately the wx has not been too bad, so I haven't been blown off course very much. Last night my timing was much better, so I think I'm getting a better feel for when to start going down just based on visual cues and my stopwatch.
