Test Pilot: Climb Test Procedures

cards brimming with numbers, it's time to transform them ... FPA Flight path angle. Figure 1 block is simply ... A persoiiali/ed membership card and EAA decals;.
2MB taille 7 téléchargements 511 vues


Stick & Rudder

est Pi

IN OCTOBER'S "TF.ST PILOT" you learned how to fly a climb performance flight

Determine the height of


The technique of flying a series of climb flights at

Performance Data Reduction

d i f f e r e n t airspeeds a n d recording c l i m b data

Turning flight-test data into something usable

through several altitude blocks was straightforward, but we cautioned you


test u s i n g a modified c h e c k - c l i m b procedure.

about the sensitivity of the data to the way you fly the tests. We stressed

precise airspeed control, repeatability, test-planning judgment, and the importance of your qualitative remarks, all of which have a say in the accuracy of your data and the usefulness of your test results. Now that you have all your data cards brimming with numbers, it's time to transform them into somet h i n g useful. The data reduction process is a little time-consuming but not difficult. This month our goal is to determine which airspeed yields the best climb rate, what that climb rate is, and how VY and climb rate vary with density altitude.

This month our goal is to determine which airspeed yields the best climb rate, what that climb rate is, and how VY and climb rate vary with density altitude. for your flight-test and postflight data reduction numbers. Figure 1 repeats that grid with test data numbers that came from a single test flight, i.e., a single climb airspeed. You should

have a set of data like these for every Crunching Numbers

Last month we provided a data grid 102


airspeed tested. Let's see how to get the Calculated numbers.

each altitude block by subtracting the bottom of the

block altitude (PAD from the top of the block altitude (PA2). Calculate the rate of

climb (ROC) through each block by dividing the block height (Diff on the grid) by the t i m e it took to c l i m b through it (see formula be-

low). If the block is in feet and the time is in seconds, multiply the result by 60 to have the answer in feet per minute. ROC =

PAZ - P41 x60 Time

Altitude blocks were necessary for timing, but they're cumbersome to use for flight planning. It's easier to use the block's midpoint altitude. This is consistent with using the average ROC through the block, but we know that the airplane climbs marginally faster at the bottom and marginally slower at the top of the block. Your postflight data check for reasonableness should have assured no significant ROC: change within the altitude blocks, and this assurance lets us use the midpoint of the blocks. The midpoint of each a l t i t u d e

Test Airspeed

Start Weight 1260 lb


Test Data

PA1 PA2 Diff Mid OAT DA


















25 40 55 75



3250 5250






9500 h_J>- 9250

tude block, and the OAT column contains the outside air temperature (in degrees Celsius for our example) for the middle of the altitude blocks. Using a density altitude chart or flight computer, determine the density altitude (DA) for each altitude block midpoint and enter these on the grid. Put this data grid aside and repeat the n u m b e r c r u n c h i n g for every tested airspeed. When you're finished, you should have several grids, each pertaining to a specific test airspeed.

End Weight I240lb


1500 1200 750 550 400 : 1

Drawing Plots

It's time to draw, and you'll need some graph paper. Starting with one grid, i.e., one airspeed, plot ROC vs. DA as shown in Figure 2a and fair a line through the data points. This line shows your climb rate for any density altitude between the mid-

Calculated RAI

Bottom of pr«i«ut« altitude block


Altitude block height Midpoint ot altitude block


RA2 Top of prtnurc attitude Mock OAT

VT Time


Outtide air t«mp

Dwftty attitude

True airspeed Elapsed time through block

Rate of climb Flight path angle

Figure 1

block is simply the altitude halfway

them in the Mid column on the grid. The Mid column contains pressure altitudes for the middle of the alti-

between PA 1 and PA2. Calculate the midpoints for each block and enter

Share TheJ(

Recreational Aviation...

Give A


EAA Membership! Present your family, friends

A Gift EAA Membership includes: • A persoiiali/ed membership card

and EAA decals; • 12 months of Sport Aviation-EAA's official membership publication; • The lowest admission rates to

and colleagues with a special gift that lasts the whole year...EAA Membership. It's the perfect way to celebrate a love

>f Recreational Aviation!

point of the lowest a l t i t u d e block and the midpoint of the highest altitude block for one airspeed.

To send a $40 Gilt LAA Membership with gift card, fill out this form and mail it with

payment to EAA, PO Box 3086, Oshkosh, WI 54903-3086. Gift From: Address: City/State/ZIP:

Gift To:____ Address:

AirVenture Oshkosh (July 24-30, 2001); • A 5% discount on aircraft insurance


through EAA's Aircraft Insurance Plan; • Reduced rales on EAA SpoitAir Workshops and all other educational prograins; • Regularly scheduled member merchandise specials; and so much more!

If you prefer, call 1-800-JOIN EAA (mention priority code GIFT) or visit our web site at www.eaa.org/holiday to order a gift


EAA Membership.

Happy Holidays from EAA! Sport Aviation


One of the fastest kit planes ever... Build and fly a RANS kit before the others are out of the garage.

Density Altitude Figure 2a

VI > V2 > V3 > V4

QUALITY AIR TIME ffflrlS 4600 Highway 183 Alternate • Hays, KS 67601 U.SA (785)

625-6346 • Fax: (785)


o •S o>


www.rans.com • [email protected]

Superflite System II Fabric Covering and Finishing Systems

Fabulous Pure Polyurethane "Wet Look" Finish

Less Work • Best Results

FAA/PMA Approved • In service over 15 years OEM • Factory installed on some of the Worlds Finest Aircraft Specified and supplied by Major Kitplane Manufacturers

Superflite System II, the finest finish system money can buy. It doesn't cost any more than old-fashioned methods and it takes HALF the number of coats.

(847) FAX:


350-4100 (847) 350-4119

1 1 1 1 Nicholas Blvd. Elk Grove Village, IL 60007

For more infwmatioo. visit SPORT AVIATION on the Web at www eaa org



Density Altitude Figure 2b

Repeat this plotting exercise for every airspeed you tested. When you're done, you should have a plot that resembles Figure 2b. (To minimize clutter, the example has only four tested airspeeds.) The more airspeeds you test, the better your climb performance accuracy will be. We labeled our example tested airspeeds from fastest to slowest as VI through V4, respectively. Figure 2b indicates airspeed V3 yields the fastest climb rates of the airspeeds tested, hut we don't know if there's some other speed that is slightly faster than V3 (between V2 and V3) or slightly slower than V3 (between V4 and V3) that produces an even better ROC. To find this intermediate speed, you'll create a new plot of ROC vs. Airspeed from your existing ROC vs. DA plot. In Figure 2b draw a vertical line up from the DA axis through the lines of different airspeeds. Draw horizontal lines from the ROC axis to the intersections of the vertical line you just drew and each airspeed line the vertical line passes through (Figure 3a). Now you can read the ROC for each corresponding airspeed at this density altitude. Create a new plot (Figure 3b) of ROC vs. Airspeed, by plotting the corresponding values from Figure 3a, and fairing a curve through these points. You can now see the maximum ROC occurs at the top of the curve at a speed









507-426-8273 Density Altitude

P.O. Box 22O-A24 Fairfax. MN 55332

Figure 3a ROC 3







ITC-401-ENR1 Portable Intercoms Featuring Enhance Noise Reduction The FlightTeeh Intercoms ITC-401-FNRI featuring the V4 V3



Exclusive Enhanced Noise Reduction circuitry, the first major intercom improvement in 30 years. •


Figure 3b

between V2 and V3. Because the vertical line in Figure 3a represents a single DA, the curve in Figure 3b applies only to that single DA. Repeat this cross-plot procedure for several density altitudes, i.e., several vertical lines on the ROC vs. DA plot (our example uses three). It doesn't matter which DAs you choose, hut it's a good idea to space them evenly. Your plot of ROC vs. Airspeed should now look like Figure 4a. The peaks of each curve represent the maximum ROC and V Y for each density altitude. To find the maximum climb rate for any of the plotted DAs, draw a horizontal line from the peak of the DA curve to the ROC axis. To find VY, draw a vertical line from the peak of the DA curve to the horizontal axis. Although Figure 4a provides a lot of very useful information, it's still a bit cumbersome. If you draw a line connecting the peaks of the DA curves, you can now find VY and its associated ROC between the plotted DAs. The problem is that you must interpolate between the plotted DAs. Another cross-plot will solve this. To create a plot of VY for all density altitudes, draw vertical lines from the peaks of the DA curves down to the Airspeed axis as shown

• •

Enhanced Nose Reduction No Squelch Controls

Continuous Quiet Communications without Hackground Noise

• •

Single Control Operation Up u, 80 hours of operation ou 9V Lithium Battery

FlightTech Intercoms


Two and l-'our F.NR1 panel mount models available.

ftW-971-9692 KAX 630-971-9742

The Evolution of *





Positioned . ' ." to Serve a • •• * -Global Community " ' J J ot decades,


Mattituck Aviation





Excellence _


'" •

. *

'.'• ''.

IMS been the. undisputed '••'.'.•' £."1. North American leader in • "'• *:.^f*.. aviation engine repair and servicing. *• ^ ^ -V As the business of aviation expanded v >• sV ". around the globe, Mattituck faced the challenge ' \ of meeting the needs of a more diverse and distant > customer base. By Joining forces with Teledyne Technologies, Mattituck's operations were strengthened, creating a more flexible corporate structure for future growth. Teledyne Mattituck Services is poised to meet the demands of emerging engine technology without compromising the personal service and attention to detail that defined the Mattituck reputation. ' • • ENCINES, PARTS and ACCESSORIES Caff BOO 624-668O Teledyne Mattituck Services, Inc. ' .



a lclcd>nc I cihnologics ( oinp;iji>




PO Box 1432/410 Airway Drive, Mattituck, NY 11952 Phone 631 298-8330 Fax:631298-8412 ' " ' ' ".pair Static ' .v.mattituck --" visji SPORT AVIATION on the Wet



5 •5

Lower DA


Higher DA



Rgure 4a

Figure 4b


a DA2

NOW WITH LONG TERM MEMORY & FUEL FLOW LF, Lean Find™automatically finds first cylinder to peak. • Automatically records up to p 70 hrs of flight. In flash memory.

• Shock Cooling, measured for I each cylinder, information is I available in degrees per minute. • Detects Alternator Failure displaying low Voltage alert. Fuel Flow /w GPS input, fuel to next waypoint, Gal/Hr. and more. • Alarms on all functions F including Fuel flow. With I remote alert lights. • TSO Quality, FAA STO for both . Fuel Flow and EGT/CHT.

• Made in the USA.

JPINSTRUMENTS Inc. J-800-345-4574

P.O. Box 7 0 3 3 Huntington Beach CA 9 2 6 1 5 O f f i c e : J 7 1 4 ) 5 5 7 - 3805 Fax:(714) 557-9840


o •8





Density Altitude

Density Altitude

Figure 5a

Figure 5b

in Figure 4b. Where the vertical lines cross the Airspeed axis is the VY for that DA. Use these V Y /DA data pairs to create a new plot of VY vs. DA (Figure 5a). Fair a line through the data points. The final step is just labeling another vertical axis on Figure 5a. The dashed line connecting the peaks of the curves in Figure 4a shows the relationship between V Y and ROC. Draw a series of vertical lines from the Airspeed axis up to this dashed line. Then draw horizontal lines from the ROC axis to the intersections of the dashed line and vertical lines you just drew. Notice that for every V Y there is only one ROC associated with it, regardless of density altitude. Draw another vertical axis on the right side of Figure 5a so it looks like Figure 5b and annotate the ROCs associated with the VYs directly across. Now you have a handy, singlesource plot t h a t shows your airplane's V Y and ROC for a range of density altitudes. No more looking up tables or percentage calculations for nonstandard temperatures or wondering about the applicability of the airplane manufacturer's claimed climb performance.

These data are useful for variations in climb schedules. Figure 4a, for example, shows the ROC penalty you'll pay if you choose to perform a cruise-climb at a speed faster than VY for better engine cooling or outside view over the nose. You can create a plot similar to Figure 5b by using your cruise-climb airspeeds instead of the peaks of the DA curves on Figure 4a. Sounds like a winter project, doesn't it? Yes, we went t h r o u g h a lot of number crunching, plotting, and cross-plotting this month, but we transformed all your raw climb performance data into a single plot for your operator's manual. Next time we'll f i l l in the V, and I;1'A columns on the data grid. We'll do a little more math and a lot less plotting as we complete our data reduction by explaining how to take that same raw data and determine your airplane's maximum climb angle and the airspeed at which it occurs (Vx). Until then, please keep sending your comments and questions to Test Pilot, EAA Publications, P.O. Box 3086, Oshkosh, WI 54903-3086 or edit[email protected]>eaa.org with TEST PILOT as the subject of your e-mail.