Brodhead Pietenpol Association

Original Posted By: "Jack Phillips"
Hopefully doing my last 1 1/4 hr tomorrow and need to get these numbers for thephase 1 signoff. Since I have a vertical speed guage, can I assume that the "best rate of climbwould be the fastest that I can go and still maintaining the highest FPM climb?And the best angle of climb would be to pull it back till the rate of climbstarts to drop off , and that would be best angle of climb?thanks,walt evansNX140DL________________________________________________________________________________

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Sorry Walt, that's too easy.There were some pretty good discussions in Sport Aviation a few months agoabout how to do these tests. Youn might want to dig through those, or go toyour local Barnes and Nobles and buy a book called "Flight Testing HomebuiltAircraft by Vaughn Askue - full of good stuff.Basically for rate of climb, you will want to do a series of tests atdifferent airspeeds and time it for a minute, holding the airspeed asconstant as possible (helps to do it early in the morning when the air isstill) and see what change you see on the altimeter in that minute. Try oneairspeed, then go back to your starting altitude (the climb rate will varywith altitude so you need to do the tests at approximately the same startingaltitude) - you can do best glide speed tests on the way down, and thenchange the airspeed by a couple of knots and do it again. Plot the resultand you will have a curve of climb rate (in feet per minute) versusairspeed. Where the curve peaks is your best rate of climb speed.Best angle of climb is done by flying along a road with two distinctlandmarks, like a powerline crossing, that you can tell when you havepassed. Fly along the road at the test airspeed and note the altimtersetting at your first landmark. Fly at that airspeed until you cross thesecond landmark and note your altitude. Do it again with differentairspeeds and plot the results on a curve of altitude climbed versusairspeed. The airspeed that gave you the most altitude climbed between yourtwo fixed landmarks is your best angle of climb speed. You would do well todo it on a windless day, or do each speed twice, once in each direction andaverage the results.Jack -----Original Message-----

Original Posted By: "w b evans"
Vy, best rate of climb, is the speed at which the airplane will gain themost altitude per unit of time.Vx, best angle of climb (I can only remember because an "x" is all angles),is the speed at which the airplane will gain the most altitude in a givenhorizontal distance.Vy would be the speed at which you can maintain the maximum rate of climb onyour VVI. If you can maintain 600 fpm, and that is the highest ROC you canhold, that speed is your Vy. (the highest rate per unit of time - a minute)Vx is usually lower than Vy. Suppose you can climb at 55 mph, but at thatspeed can only maintain 500 fpm, while at 60 mph you can maintain 600 fpm.This is where you have to do some math. At 55 mph and 500 fpm, you gain 968feet per 100 feet you move forward. At 60 mph and 600 fpm, you only gain880 feet per 100 feet forward. (I hope my math is right, but it still makesmy point if it is not). Therefore, 55 mph would be your best angle while 60mph would be your best rate.So, the short answer to the question is that you can read your best rate offof the VVI, but have to calculate your best angle by recording your bestmaintainable ROC at different airspeeds and comparing them.Make sense?Gene----- Original Message -----

Original Posted By: Gary Gower