Ranking Aerobatic Aircraft

Discussion in 'Aerobatics' started by Greebo, Feb 11, 2005.

  1. Greebo

    Greebo N9017H - C172M (1976)

    Joined:
    Feb 11, 2005
    Messages:
    11,011
    Location:
    Baltimore, MD
    Display Name:

    Display name:
    Retired Evil Overlord
    Welcome!

    Welcome to the new "Pilots of America" Forums. You've found us in our infancy right now - we're still working out the specifics of our setup and administration - but feel free to register an account, hop on in and say hello!

    In the near future, we will be setting up a series of Aviation related forums for US based Pilots and anyone else with an interest in or, more likely, passion for aviation.

    Right now our Administrative Council is still working out the details, and as decisions are made, the look, feel, and content of these forums are subject to potentially radical change. So please pardon our dust, put on a set of non-polarized sunglasses, put your tray up and lock it and return your seat to its upright position, and take off with Pilots of America!

    Chuck "Greebo" Haeberle, PP-ASEL
     
  2. Toby

    Toby Cleared for Takeoff

    Joined:
    Feb 22, 2005
    Messages:
    1,075
    Location:
    Long Island, NY
    Display Name:

    Display name:
    Toby Speed
    Re: Citabrias ...

    Ken, following up on your comment about modern standards, which aircraft is considered today's best acro machine? Also, what are the qualities that define the best aerobatic planes? I'm guessing horsepower and wing shape are two. Is more power always better, or just up to a point?
     
  3. citationxjl

    citationxjl Pre-takeoff checklist

    Joined:
    Feb 24, 2005
    Messages:
    212
    Location:
    Chandler, AZ
    Display Name:

    Display name:
    Jeff
    Re: Citabrias ...

    From the looks of it, and a few world aerobatic championships, Kirby Chambliss chose the Edge 540. It has an unbeliveable roll rate (420 degrees a second). It is my favorite to watch. Here is a pic from Luke Day 2005
     
    Last edited: Apr 15, 2005
  4. gibbons

    gibbons En-Route

    Joined:
    Feb 12, 2005
    Messages:
    3,386
    Location:
    Rogers, Arkansas
    Display Name:

    Display name:
    iRide
    Re: Citabrias ...

    Toby,

    Not Ken but I couldn’t resist the question.

    In my opinion, the best measure of aerobatic airplanes is what Alan Cassidy developed and calls an “Aerobatic Performance Index”. He discusses it in his book (page 64). It uses a “formula” place a value on an aircraft as an aerobatic performer. In summary, there are three components of this index:

    Power/Weight ratio
    Maximum level speed
    Maximum roll rate

    The calculation is:
    pwi = Power (hp) / Weight (kg) / 0.36
    msi = Max level speed (knots) / 165
    rri = 1.6 / e(220/(roll rate exp 1.1))
    API = pwi * msi * rri * 50

    The roll rate is complicated but is designed to give decreasing benefit to roll rates in excess of 420 degrees / sec.

    As Cassidy himself states, “[The index] has not been put to any official use in defining standards, but it has been useful in policy discussions and bar talk alike.”

    I believe I have a spreadsheet at home that does the calculations and if I find it this evening I’ll edit this post and include it as an attachment. You can input the numbers for your own airplane and see how it stacks up.

    As an overview, here are a few aircraft and their API’s:

    Pitts S2A – mid 30’s
    Extra 200 – mid 40’s
    Pitts S2B - low 50’s
    Giles G202 – mid 60’s
    Extra 300S – mid 70’s
    Sukhoi 31 – mid 80’s
    Edge 540 (highest) – low 90’s

    The “best of the best” in these rankings are the Edge 540, the Sukoi 31, the Pitts S-1-11B (described to me by one airshow pilot as a huge engine with a balsawood airframe), and the CAP-232. Sad to say Extra 300/L is no longer considered a serious unlimited contender. I’ll have to calculate its API tonight. I’m going to guess somewhere in the mid 60’s.

    Chip
     
  5. Toby

    Toby Cleared for Takeoff

    Joined:
    Feb 22, 2005
    Messages:
    1,075
    Location:
    Long Island, NY
    Display Name:

    Display name:
    Toby Speed
    Re: Citabrias ...

    Chip,

    Excellent! I look forward to the spreadsheet.

    No wonder I liked the Sukhoi. I have to find out which model it was. Somehow I'm thinking 29, but I don't know where I got that number. Let us know how the Extra stacks up.

    At what API is an airplane able to do all the maneuvers, I wonder? I mean all the basic maneuvers including the vertical ones.

    Also, I wonder which aircraft has the highest + and - G loading?

    Sorry, this thread is creeping away from the initial subject. Should I move it?
     
  6. Skyport

    Skyport Pre-Flight

    Joined:
    Feb 25, 2005
    Messages:
    52
    Location:
    Bethlehem PA
    Display Name:

    Display name:
    Tom
    Seemingly lost in this discussion of the BEST is the fact that an entire generation of pilots learned aerobatics in aircraft that had flat bottomed airfoils, no inverted anything, relatively low power to weight ratios, and high drag, in fact aircraft that had performance remarkably similar to a current, garden variety, 7GCAA Citabria, not even a Decathalon. Given that they learned aerobatics in such pedestrian aircraft it is nothing short of amazing that the WWII fighter pilots had so much success in combat??????????

    We seem to be obsessed with having the best when in fact as a trainer an aircraft with less performance, lower power, higher drag, lower roll rate will force the student to develop better planning, better stick and rudder skills. Bill Kershner spent years teaching aero in Cessna 150/152 Aerobats because they were easy for the student to fly, because they were cheap.......

    Duane Cole put on a flawless exhibition everytime he strapped on his clipped wing, 150 HP/inverted fuel/oil, Taylorcraft. In fact I've seen the audience turn away from a high-energy snarling Pitts performance in boredom BUT stand transfixed in awe watching Duane FLY, no tumbling all flying, a graceful performance in the T-craft, and end it with the same performance deadstick. No one ever looked away when Bob Hoover FLEW his very graceful demonstration in anything, especially the Aero Commander.

    BEST...............for what? High-energy, high G aero, audience appreciation, training, all VERY different missions, all have very different requirements. Instead of obsessing on the best aircraft we should concentrate on developing the highest level of skills suitable to our mount of choice.

    There was a time when airshows were flown in clipped wing Cubs, Great Lakes, Stearmans (both stock and 450 HP), Citabrias.........before Decathlons, a good argument can be made that those shows were more interesting to watch, and that it required a different skill set, much closer attention to available energy, to do aero in a long winged, high drag, low thrust, flat bottomed, aircraft.

    Tom-
     
    Diana likes this.
  7. Dave Krall CFII

    Dave Krall CFII Final Approach

    Joined:
    Mar 4, 2005
    Messages:
    5,022
    Location:
    Seattle WA
    Display Name:

    Display name:
    Dave Krall CFII SEL SES, Cmcl HELI
    A Cessna AEROBAT is the best.

     
  8. Greebo

    Greebo N9017H - C172M (1976)

    Joined:
    Feb 11, 2005
    Messages:
    11,011
    Location:
    Baltimore, MD
    Display Name:

    Display name:
    Retired Evil Overlord
    That's odd.

    How did the posts in this thread get attached to one of my old old posts?
     
  9. gibbons

    gibbons En-Route

    Joined:
    Feb 12, 2005
    Messages:
    3,386
    Location:
    Rogers, Arkansas
    Display Name:

    Display name:
    iRide
    Tom, you are correct and your is point well taken. I fell into the "best means highest performance" trap, and that isn't the case. And I couldn't agree more with your statement about "developing the highest level of skills suitable to our mount of choice."

    The flip side of this is how often I hear that I should learn aerobatics in a lower performance aircraft before moving to something like an Extra. I don't agree with that at all. Learning to fly aerobatics in a Citabria does not prepare me for flying aerobatics in an Extra, just like learning to fly aerobatics in an Extra does not prepare me for flying aerobatics in a Citabria. "You're only current in what you're current in." It's all about "skills suitable to our mount of choice."

    Thanks for the reset.

    Chip

    (By the way, my current favorite airshow performance is Bobby Younkin in the Super Decathlon. Absolutely unbelievable what he can do with that airplane.)
     
  10. gibbons

    gibbons En-Route

    Joined:
    Feb 12, 2005
    Messages:
    3,386
    Location:
    Rogers, Arkansas
    Display Name:

    Display name:
    iRide

    Uh, I have no idea. I think Brian was messing with the thread tools and he must have screwed something up. :rolleyes:

    Chip
     
  11. poadeleted3

    poadeleted3 Pattern Altitude

    Joined:
    Mar 2, 2005
    Messages:
    2,055
    For the right $$$$ amount, I can be bought to back your story up
     
  12. gibbons

    gibbons En-Route

    Joined:
    Feb 12, 2005
    Messages:
    3,386
    Location:
    Rogers, Arkansas
    Display Name:

    Display name:
    iRide
    PayPal OK?
     
  13. Greebo

    Greebo N9017H - C172M (1976)

    Joined:
    Feb 11, 2005
    Messages:
    11,011
    Location:
    Baltimore, MD
    Display Name:

    Display name:
    Retired Evil Overlord
    I think Joe needs at least 2 or 3 flight hours worth for me to buy this story.

    And I need a few too.

    You already know my paypal address though. :)
     
  14. gibbons

    gibbons En-Route

    Joined:
    Feb 12, 2005
    Messages:
    3,386
    Location:
    Rogers, Arkansas
    Display Name:

    Display name:
    iRide
    As promised, here's the spreadsheet. You can plug the numbers into the spreadsheet yourself (green cells) to see where your mount falls on the scale.

    It's an attempt to quantify a subjective argument about performance, but I think it has value. It may be difficult to see the difference between a Pitts S2B and a Pitts S2C, but the magnitude of difference in performance between a Super Decathlon and a Sukhoi 26 is apparent.

    Yours for discussion.

    Chip
     
    Last edited: Apr 15, 2005
  15. Skyport

    Skyport Pre-Flight

    Joined:
    Feb 25, 2005
    Messages:
    52
    Location:
    Bethlehem PA
    Display Name:

    Display name:
    Tom
    Harold Johnson was famous for low altitude loops, rolls, and spins..................in a Ford Tri-motor. I strongly suspect he would be capable of quickly checking himself out in an Extra and doing a similar performance. I doubt that there are many (any) Extra pilots who could quickly do the opposite.

    How many have ever seen an aero performace in a stock Stearman, if you've ever flown one you will surely appreciate the skill required. For many years after WWII that, and the 450 HP version, was the aero mount of choice, in fact the oft maligned 7GCAA/GCBC has a better HP to weight ratio and is in fact a much better aero mount than a stock Stearman, and quite comparable to a 450 Stearman.

    Once again, learn to fly what you have, learn to make one plane sing and dance and you will be able to quickly makes others walk and talk.

    Tom-
     
  16. Diana

    Diana Final Approach

    Joined:
    Feb 21, 2005
    Messages:
    6,167
    Location:
    Southwest MO
    Display Name:

    Display name:
    Diana
    Once again, we will have to agree to disagree. Where is Marty Mayes, btw? I miss him.

    You should be flying with him in the Decathlon when he does maneuvers. It's like no other flying I've ever done. It was smooth as silk, and flawless flying; like a dream.
     
    Last edited: Apr 15, 2005
  17. Diana

    Diana Final Approach

    Joined:
    Feb 21, 2005
    Messages:
    6,167
    Location:
    Southwest MO
    Display Name:

    Display name:
    Diana

    Tom, it's nice to have you posting here. You add years of experience and a wealth of knowledge. :)
     
    Last edited: Apr 15, 2005
  18. gibbons

    gibbons En-Route

    Joined:
    Feb 12, 2005
    Messages:
    3,386
    Location:
    Rogers, Arkansas
    Display Name:

    Display name:
    iRide
    I have no doubt that he could, but could he make the Extra or an Edge 540 fly to it's fullest extent in short order? Low altitude loops, rolls, and spins aren't even close. How long do you think it would take Wagstaff to figure out how to roll anything, including a Tri-motor at any altitude?

    But we're talking hypothetically here. My point is simply that you learn to fly any aircraft well by flying THAT aircraft, and not by flying any other.

    Chip
     
  19. gibbons

    gibbons En-Route

    Joined:
    Feb 12, 2005
    Messages:
    3,386
    Location:
    Rogers, Arkansas
    Display Name:

    Display name:
    iRide
    Yep, it's not the first or last time.
     
  20. Toby

    Toby Cleared for Takeoff

    Joined:
    Feb 22, 2005
    Messages:
    1,075
    Location:
    Long Island, NY
    Display Name:

    Display name:
    Toby Speed
    Thanks for the spreadsheet, Chip. I'm out of town right now, but will work with it when I get home.

    I don't see why you say it's subjective. If you're calculating weight: power and other quantifiables, the results should be pretty clearcut.
     
  21. vontresc

    vontresc En-Route

    Joined:
    Aug 8, 2006
    Messages:
    3,488
    Location:
    Madison
    Display Name:

    Display name:
    vonSegelGoober
    Hmmm would this be the ultimate Necropost??????? It being ThreadID 1 and all :D
     
  22. ScottM

    ScottM Taxi to Parking

    Joined:
    Jul 19, 2005
    Messages:
    42,564
    Location:
    Variable, but somewhere on earth
    Display Name:

    Display name:
    iBazinga!
    Re: Welcome!

    It is 4 years later and you are still working on the "specifics"

    ;)
    ;)

    :D:D
     
  23. wsuffa

    wsuffa Touchdown! Greaser!

    Joined:
    Feb 22, 2005
    Messages:
    22,554
    Location:
    DC Suburbs
    Display Name:

    Display name:
    Bill S.
    Re: Welcome!

    In the beginning.... there was a blue board
     
  24. Diana

    Diana Final Approach

    Joined:
    Feb 21, 2005
    Messages:
    6,167
    Location:
    Southwest MO
    Display Name:

    Display name:
    Diana
    Re: Welcome!

    :D

    Remember when the yellow board ended before it became the red board? Several of us were there the second it shut down. The last post was from Len, I think, who posted..."And thanks for all the fish."

    Found the thread about it:

    http://www.pilotsofamerica.com/forum/showthread.php?t=863b
     
    Last edited: Nov 5, 2011
  25. Red Air Rambo

    Red Air Rambo Pre-takeoff checklist

    Joined:
    Nov 7, 2011
    Messages:
    152
    Location:
    Tulsa, Ok
    Display Name:

    Display name:
    Rambo
    Re: Citabrias ...

    I would think the Christen Eagle would be in there between the S2A & B/C...Always a fun plane to fly....a little tricky in a strong x-wind though IMHO.
     

    Attached Files:

    Last edited: Dec 19, 2011
  26. Anthony

    Anthony Touchdown! Greaser!

    Joined:
    Feb 23, 2005
    Messages:
    18,613
    Display Name:

    Display name:
    Anthony
    WTF? Does Chuck still exist in the ether of the pilot world?
     
  27. Red Air Rambo

    Red Air Rambo Pre-takeoff checklist

    Joined:
    Nov 7, 2011
    Messages:
    152
    Location:
    Tulsa, Ok
    Display Name:

    Display name:
    Rambo
    I don't know Chuck...I just joined and did not want the Eagle to be slighted. :dunno:

    Brent
     
  28. N801BH

    N801BH Touchdown! Greaser! Gone West

    Joined:
    Jul 7, 2008
    Messages:
    17,188
    Location:
    Jackson Hole Wy
    Display Name:

    Display name:
    FBH

    Yup... Frank Christenson would not want that either.:no::no::no::idea: