limitations and weight and balance
TRANSCRIPT
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Limitations and Weight and Balance
J. Wolper
Idaho State University
FIRC Pocatello, ID
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Outline
1 A Mystery
2 Accidents
3 Weight and Balance Issues
4 Glider Nerd Calculations
5 Zero Fuel Weight
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Cessna 152 POH
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
The tables show stall speed (in calibrated airspeed) atvarious flap and bank combinations. There’s only oneweight shown (since a 152 is always at Maximum TakeoffWeight); other POHs show how stall speed varies withweight.It’s my opinion that if you can answer all of the “why?"questions this table raises then you really know youraerodynamics.We’ll come back to this!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
The tables show stall speed (in calibrated airspeed) atvarious flap and bank combinations. There’s only oneweight shown (since a 152 is always at Maximum TakeoffWeight); other POHs show how stall speed varies withweight.It’s my opinion that if you can answer all of the “why?"questions this table raises then you really know youraerodynamics.We’ll come back to this!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
The tables show stall speed (in calibrated airspeed) atvarious flap and bank combinations. There’s only oneweight shown (since a 152 is always at Maximum TakeoffWeight); other POHs show how stall speed varies withweight.It’s my opinion that if you can answer all of the “why?"questions this table raises then you really know youraerodynamics.We’ll come back to this!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Accidents
Information from ntsb.gov
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
January 4, 2010, Cessna 172, Bangor, ME
This was the first leg of a ferry flight to Europe. Unable to climbin IMC, the pilot told the controller that he was “a bit heavy".There were AIRMETs for moderate icing and moderateturbulence, which seems like a bit much for an overloaded 172,but the pilot admitted to FSS that he might have to turn around.The pilot reported “control difficulties" and “extreme turbulence"with “90 degree banks." In IMC!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Problem: higher weight meant dramatic performancereduction!Problem: Aft CG (probably within the envelope, if therewere an envelope for that weight) meant reduced stability .Factor for later: pilot’s 1st class medical was from 2 yearsprevious, so he could only exercise private pilot limitations.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Problem: higher weight meant dramatic performancereduction!Problem: Aft CG (probably within the envelope, if therewere an envelope for that weight) meant reduced stability .Factor for later: pilot’s 1st class medical was from 2 yearsprevious, so he could only exercise private pilot limitations.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Problem: higher weight meant dramatic performancereduction!Problem: Aft CG (probably within the envelope, if therewere an envelope for that weight) meant reduced stability .Factor for later: pilot’s 1st class medical was from 2 yearsprevious, so he could only exercise private pilot limitations.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 26, 2009, PA32R-300 Saratoga, Gaston’s, AR
Temperature 27, dewpoint 23, so it was hot and humid. Grassstrip. No wind. Density Altitude! 3200 foot runway butcomputed distance to clear a 50’ obstacle was 3190.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Pilot did a no-flap takeoff (I use 10◦ in the PA32).Witnesses reported control problems during the very shortflight.Airplane was 188 pounds over MTOWCG was at aft end of envelope, so stability was reduced.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Pilot did a no-flap takeoff (I use 10◦ in the PA32).Witnesses reported control problems during the very shortflight.Airplane was 188 pounds over MTOWCG was at aft end of envelope, so stability was reduced.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Pilot did a no-flap takeoff (I use 10◦ in the PA32).Witnesses reported control problems during the very shortflight.Airplane was 188 pounds over MTOWCG was at aft end of envelope, so stability was reduced.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Pilot did a no-flap takeoff (I use 10◦ in the PA32).Witnesses reported control problems during the very shortflight.Airplane was 188 pounds over MTOWCG was at aft end of envelope, so stability was reduced.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
January 30, 2009, Seneca, Huntington, WV
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Airplane was over gross, violated maximum zero fuelweight, and CG was 3” aft of the envelope on takeoff.But that’s not what killed them!Non–IFR pilot lost control trying to do a surveillanceapproach. There was no briefing, no IFR flight plan, and nocontact with anyone until he was low on fuel, altitude andideas.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Airplane was over gross, violated maximum zero fuelweight, and CG was 3” aft of the envelope on takeoff.But that’s not what killed them!Non–IFR pilot lost control trying to do a surveillanceapproach. There was no briefing, no IFR flight plan, and nocontact with anyone until he was low on fuel, altitude andideas.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Airplane was over gross, violated maximum zero fuelweight, and CG was 3” aft of the envelope on takeoff.But that’s not what killed them!Non–IFR pilot lost control trying to do a surveillanceapproach. There was no briefing, no IFR flight plan, and nocontact with anyone until he was low on fuel, altitude andideas.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
February 8, 2009, 206, Puerto Rico
Part 135 flight with 6 people and full fuel. Calculated takeoffweight 343 pounds over gross. Calculated CG aft of limit.Aircraft broke up while maneuvering under a thunderstorm.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
July 14, 2009, CH 701, Wasilla, AK
An FAA inspector was giving a recurring DPE flight proficiencycheck. They crashed on takeoff. This accident killed a Fed anda DPE!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Aircraft was calculated to be 36lb over MTOW, usingmedical records and assuming 1 hour fuel with 20 minutereserve. Sorry, but 36 pounds won’t kill you, especially inAlaska.But they planned to go fishing after the checkride soprobably had more fuel.Problem: Carbon Monoxide? (NTSB is a little vague onthis)
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Aircraft was calculated to be 36lb over MTOW, usingmedical records and assuming 1 hour fuel with 20 minutereserve. Sorry, but 36 pounds won’t kill you, especially inAlaska.But they planned to go fishing after the checkride soprobably had more fuel.Problem: Carbon Monoxide? (NTSB is a little vague onthis)
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Aircraft was calculated to be 36lb over MTOW, usingmedical records and assuming 1 hour fuel with 20 minutereserve. Sorry, but 36 pounds won’t kill you, especially inAlaska.But they planned to go fishing after the checkride soprobably had more fuel.Problem: Carbon Monoxide? (NTSB is a little vague onthis)
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
June 1, 2007, Husky, Loa, UT. Animal Control Flight, CGway aft of envelope, lost control during low-levelmaneuvering.March 27, 2005, Christen Eagle, Iowa City, IA. Doingaerobatics over-gross, CG aft of envelope, and not wearingparachutes.THIS STUFF KILLS PEOPLE!. . . along with . . .low-level maneuvering;VFR-into-IFR;thunderstorms,carbon monoxide; anddensity altitude.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Weight
Weight problems make all of the accident factors worse byincreasing stall speed;reducing Va;reducing climb rate; andincreasing runway requirements
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Weight
Weight problems make all of the accident factors worse byincreasing stall speed;reducing Va;reducing climb rate; andincreasing runway requirements
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Weight
Weight problems make all of the accident factors worse byincreasing stall speed;reducing Va;reducing climb rate; andincreasing runway requirements
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Weight
Weight problems make all of the accident factors worse byincreasing stall speed;reducing Va;reducing climb rate; andincreasing runway requirements
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Good things about high weight
reduced Vmc ;increased glide speed without any change of glide ratio;reduced turbulence effects.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Good things about high weight
reduced Vmc ;increased glide speed without any change of glide ratio;reduced turbulence effects.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Good things about high weight
reduced Vmc ;increased glide speed without any change of glide ratio;reduced turbulence effects.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Balance
Balance problems make accident factors worse by
reduced stability at aft CG;higher stall speed at forward CG; anddifficult stall recovery at forward CG.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Balance
Balance problems make accident factors worse by
reduced stability at aft CG;higher stall speed at forward CG; anddifficult stall recovery at forward CG.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Balance
Balance problems make accident factors worse by
reduced stability at aft CG;higher stall speed at forward CG; anddifficult stall recovery at forward CG.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Good things about aft CG:
higher cruise speed due to lower tail-down force required;easier aerobatics;reduced Vmc
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Good things about aft CG:
higher cruise speed due to lower tail-down force required;easier aerobatics;reduced Vmc
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Good things about aft CG:
higher cruise speed due to lower tail-down force required;easier aerobatics;reduced Vmc
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Stall Speed Table
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Three things about the tables are not mysterious:
As the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs weight increases, stall speed increases.What about the Center of Gravity? Why is the stallspeed higher at a more forward CG?
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Three things about the tables are not mysterious:
As the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs weight increases, stall speed increases.What about the Center of Gravity? Why is the stallspeed higher at a more forward CG?
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Three things about the tables are not mysterious:
As the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs weight increases, stall speed increases.What about the Center of Gravity? Why is the stallspeed higher at a more forward CG?
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Three things about the tables are not mysterious:
As the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs the bank angle increases the load factor increases sothe stall speed increases. This goes back to the old “whatmakes an airplane turn?" questionAs weight increases, stall speed increases.What about the Center of Gravity? Why is the stallspeed higher at a more forward CG?
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Lift
Lift equation
L =12
CLSρV 2
H U H ?????CL is the coefficient of lift which depends on angle ofattack and only on angle of attack;S is the wing area;ρ is the air density;V is the true airspeed.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Lift
Lift equation
L =12
CLSρV 2
H U H ?????CL is the coefficient of lift which depends on angle ofattack and only on angle of attack;S is the wing area;ρ is the air density;V is the true airspeed.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Lift
Lift equation
L =12
CLSρV 2
H U H ?????CL is the coefficient of lift which depends on angle ofattack and only on angle of attack;S is the wing area;ρ is the air density;V is the true airspeed.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Lift
Lift equation
L =12
CLSρV 2
H U H ?????CL is the coefficient of lift which depends on angle ofattack and only on angle of attack;S is the wing area;ρ is the air density;V is the true airspeed.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Lift
Lift equation
L =12
CLSρV 2
H U H ?????CL is the coefficient of lift which depends on angle ofattack and only on angle of attack;S is the wing area;ρ is the air density;V is the true airspeed.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Lift
Lift equation
L =12
CLSρV 2
H U H ?????CL is the coefficient of lift which depends on angle ofattack and only on angle of attack;S is the wing area;ρ is the air density;V is the true airspeed.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Coefficient of Lift
A stall happens when you are at the angle-of-attack formaximum CL.Where is the Center of Gravity in this?
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Wing Loading
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
All forces on the airframe (except weight) can induce torquearound the center of gravity (CG).
if the center of thrust is above the CG, there is nose-downpitching momentif center of drag is below the CG, there is nose-downpitching momentcenter of thrust being right of CG causes left-turningtendencycenter of lift behind CG induces nose-down pitchingmoment. That’s why we have tails: tail-down force inducesnose-up pitching moment. That’s stability!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
All forces on the airframe (except weight) can induce torquearound the center of gravity (CG).
if the center of thrust is above the CG, there is nose-downpitching momentif center of drag is below the CG, there is nose-downpitching momentcenter of thrust being right of CG causes left-turningtendencycenter of lift behind CG induces nose-down pitchingmoment. That’s why we have tails: tail-down force inducesnose-up pitching moment. That’s stability!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
All forces on the airframe (except weight) can induce torquearound the center of gravity (CG).
if the center of thrust is above the CG, there is nose-downpitching momentif center of drag is below the CG, there is nose-downpitching momentcenter of thrust being right of CG causes left-turningtendencycenter of lift behind CG induces nose-down pitchingmoment. That’s why we have tails: tail-down force inducesnose-up pitching moment. That’s stability!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
All forces on the airframe (except weight) can induce torquearound the center of gravity (CG).
if the center of thrust is above the CG, there is nose-downpitching momentif center of drag is below the CG, there is nose-downpitching momentcenter of thrust being right of CG causes left-turningtendencycenter of lift behind CG induces nose-down pitchingmoment. That’s why we have tails: tail-down force inducesnose-up pitching moment. That’s stability!
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
At the stall,
ForwardCG ⇒ more tail down force⇒ more lift required⇒ more speed!
We need more speed because we cannot increase the angle ofattack.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Maximum Gross Weight
Lift equation L = 12CLSρV 2
When you have more weight you need more lift so youneed more speed or more angle-of-attack.Rate of climb depends on excess thrust ; more weightmeans less excess thrust.
RC =33,000thpexcess
W
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Maximum Gross Weight
Lift equation L = 12CLSρV 2
When you have more weight you need more lift so youneed more speed or more angle-of-attack.Rate of climb depends on excess thrust ; more weightmeans less excess thrust.
RC =33,000thpexcess
W
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Maximum Gross Weight
Lift equation L = 12CLSρV 2
When you have more weight you need more lift so youneed more speed or more angle-of-attack.Rate of climb depends on excess thrust ; more weightmeans less excess thrust.
RC =33,000thpexcess
W
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Glider Nerd Calculations
Take a 3000 lb airplane with 10:1 glide ratio, so L/D = 10.Straight-and-level flight means T = D, so L = 3000lbmeans D = 300lb.At 100 knots this is 10,000 ft/sec so Brake Horsepower is300×10000
33000 ≈ 91BHP. If total horsepower available is 140,then the climb rate is
(140− 91)× 330003000
= 550 fpm
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Glider Nerd Calculations
Take a 3000 lb airplane with 10:1 glide ratio, so L/D = 10.Straight-and-level flight means T = D, so L = 3000lbmeans D = 300lb.At 100 knots this is 10,000 ft/sec so Brake Horsepower is300×10000
33000 ≈ 91BHP. If total horsepower available is 140,then the climb rate is
(140− 91)× 330003000
= 550 fpm
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Glider Nerd Calculations
Take a 3000 lb airplane with 10:1 glide ratio, so L/D = 10.Straight-and-level flight means T = D, so L = 3000lbmeans D = 300lb.At 100 knots this is 10,000 ft/sec so Brake Horsepower is300×10000
33000 ≈ 91BHP. If total horsepower available is 140,then the climb rate is
(140− 91)× 330003000
= 550 fpm
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Glider Nerd Calculations
Take a 3000 lb airplane with 10:1 glide ratio, so L/D = 10.Straight-and-level flight means T = D, so L = 3000lbmeans D = 300lb.At 100 knots this is 10,000 ft/sec so Brake Horsepower is300×10000
33000 ≈ 91BHP. If total horsepower available is 140,then the climb rate is
(140− 91)× 330003000
= 550 fpm
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Now make it a 4000 lb airplane. Drag is up to 400 pounds,which translates into 121BHP. Now rate of climb at 140BHP isonly
(140− 121)× 330004000
= 156 fpm
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Accomodates bending moments so usually only applies tomultis.Seneca: MZFW = 4000 pounds or 4032 pounds with heavyduty landing gear and alternators.Why the increase? Extra weight in the nacelles means lessbending moment at the wing roots.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Accomodates bending moments so usually only applies tomultis.Seneca: MZFW = 4000 pounds or 4032 pounds with heavyduty landing gear and alternators.Why the increase? Extra weight in the nacelles means lessbending moment at the wing roots.
J. Wolper Limitations
A MysteryAccidents
Weight and Balance IssuesGlider Nerd Calculations
Zero Fuel Weight
Accomodates bending moments so usually only applies tomultis.Seneca: MZFW = 4000 pounds or 4032 pounds with heavyduty landing gear and alternators.Why the increase? Extra weight in the nacelles means lessbending moment at the wing roots.
J. Wolper Limitations