Pietenpol Weight and Balance; Inputs for configuration calculation.

Builders,

If you are one of the Pietenpol builders who picked up a copy of our new Pietenpol Weight and Balance manual ,, and you would like to send in your data so we can assist you in getting your wing and landing gear into optimized locations, here is the information I will need:

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(A) The type of engine and the proposed propeller.

Ie: ” Ford with wood prop” or Continental 65, hand prop , Wood Prop” Or Corvair with a Warp Drive” Or “O-200 with electric start and a metal prop”

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(B) Length Of fuselage.

Long or Short (IMHO, no one should build a short fuselage plane if they are just starting. It has no advantages. )

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(C) The Pilots’s weight.

Your weight, dressed in a jacket, with headset, ready to fly. It also helps to know the pilots height, as the CG of a  5’6″ 200lb guy is a bit forward of a 6’4″ 200lb guy

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(D) The range of pilots weights

If you have friends who will test fly or likely be trusted to fly your plane, this important, and the most Piets can be set up to cover a 120–150 pound range of pilots.  So let me know if you are one of the lightest or one of the heaviest people who will fly the plane. Consider if you will have a kid or grandkid who might fly it when they are in the 120-130lb range.

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(E) Fuel Tank Location(s) and capacities.

Let me know where the fuel tank is, and what capacity it is. If the tank is in the fuselage, please reference its location in inches from the firewall. If you have a 12 gallon fuselage tank, and it is 16″ long, send me a note saying something like “12 gallons, with the center of the tank 9″ aft of the front face of the firewall.”

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(F) Unusual features: 

A full plywood fuselage; A glove box with a capacity of more than 8 pounds; Unusually heavy or different tailwheel and spring arrangements; Super light covering like Oratec; Pilots seat back location tilted more than 1.5″ from where the plans show. Please note these differences.

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Where do you  send (A) though (F)? 

I would greatly prefer if builders send the information right to the comments section here. If you send the information to the comments, in a few days I will come back with a specific recommendation.

If you are a bit concerned about sending your actual weight out on the internet because Cameron Diaz haunts your profile page on Match.com where you shaved 20 pounds off the actual number, and now you don’t want to get busted and have it ruin her image of you as a scrupulously honest character, no worries, I understand completely. Just send the info with your initials, and when she calls me with her suspicions, I’ll totally deny it’s you.  Thank me later, it just the kind of guy I am.

Seriously, don’t send in ‘optimistic’ numbers, the subject is a little too serious for vanity to show up in your numbers. Over the years we have had at least 6 successful pilots of Corvair Powered planes who had personal flying weights in the 300+ club, I can get your Piet weight and balance in range if I know the number. If you are 265#, sorry, it will not even make honorable mention in pantheon of pilots who could have been NFL defensive linemen.

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If you would like to watch a one hour forum I gave on Weight and Balance of Pietenpol’s, including an extensive question and answer session, click on the youtube link above, it will take you directly to my channel. If you have not yet done so, please take a moment to subscribe.

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WW.

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About William Wynne
I have been continuously building, testing and flying Corvair engines since 1989. Information, parts and components that we developed and tested are now flying on several hundred Corvair powered aircraft. I earned a Bachelor of Science in Professional Aeronautics and an A&P license from Embry-Riddle Aeronautical University, and have a proven 20 year track record of effectively teaching homebuilders how to create and fly their own Corvair powered planes. Much of this is chronicled at www.FlyCorvair.com and in more than 50 magazine articles.

23 Responses to Pietenpol Weight and Balance; Inputs for configuration calculation.

  1. Robert E Glab says:

    Morning, it was a blast to attend your forum at airventure. Thanks for your work. I am building now.

    A) Corvair, Warp Drive Prop
    B) Long Fuse
    C) I could weigh as much as 275, Ide assume I am about the largest person that will be flying my plane.
    D)As far as a weight range I suppose i would like it setup so the heaviest pilot would be 280 and have the range include as light a pilot that I could within reason.
    E) I am not at that stage yet, but I plan on as large of a fuel tank that I could do in a single center section tank,
    F) I plan on using Oratex, and I would like to tilt my pilot seat back 1.5″.

    I am still very new to the build process, Any advice from you would be apprecated and followed. Again, thanks for your work on these beautiful machines.

    Robert Glab
    (928) 379-2248
    heliglab@gmail.com

  2. Casey Welch says:

    A. Corvair, Wood Sensenich
    B. Long Fuse
    C. Currently weigh about 210 lbs ready to fly. 6’4” tall.
    D. Lightest pilot ~ 130 lbs. Heaviest ~ 280 lbs.
    E. Open for ideas here. Wing is not yet built. Prefer largest possible wing tank, no header or fuselage tank if possible for simplicity. Again, open for recommendations.
    F. Oratex covering. Pilot seat tilted back 1.5”. Harley wheels. Open for your best tailwheel recommendation.

    I’m also early in the game. My plan is to take this opportunity to begin to gather best data and info to get it right from the start. Really appreciate your guidance William.

  3. Ned Lebens says:

    A) Corvair with Warp Drive.
    B) Long.
    C) 6’0″ 200lbs.
    D) 140lbs – 260lbs range.
    E) Center section tank. 16 gallons.
    F) Pilot’s seat back tilted back extra 2.5″ at top longerons. Fuselage is 2″ taller from firewall to tailpost.

    Thank you!
    Ned Lebens

    • Peter Jones says:

      Great presentation @ Brodhead.
      Thx for the help!

      A) Corvair w/ wood or Sensich adjustable, WW
      motor mount
      B) Long fuse
      C) P. Wt. 190#
      D) Range 145-220#
      E) Frt. tank 12.1 gal. CG 9″ behind FW
      Ctr. section tank 13.5 gal.
      F) Ctr. struts +2″
      Matco tailwheel on steel leaf spring
      Straight axle w hyd. disc brakes
      Oil cooler mounted at very front
      Odessy battery against rr of FW
      Panel full of gauges
      Significantly enlarged rr glovebox to fit a
      sleeping bag.

  4. Arthur Davison says:

    I didn’t make it out to Oshkosh this year but I would like to get a copy of the weight and balance manual as soon as it’s available online.

    A) Corvair w/ wood prop
    B) Long
    C) 6’2″ 260 lbs.
    D) I don’t anticipate anyone else flying it, but a 170-270 range for the pilot would be good.
    E) 17 gallon center section tank.
    F) Steel tube fuselage, Ribblet 612 Wing, I have a shelf above the passenger’s rudder controls that could probably hold 40 lbs. I’m also leaning towards oratex covering.

    To make a long version of the steel tube plans I compared the dimensions of the long and short fuselage bays and added that difference to the corresponding bays on the steel plans. I also made it 2″ deeper. The lower longeron is a 7/8″ x 0.035″ tube from the firewall to 12″ behind the pilot’s cockpit and then 3/4″ x 0.035″ back to the tail. Top longeron is 3/4″ x 0.035″ the entire length.

    Thank you for all the great work that you’ve done!

  5. Chris Pirrmann says:

    A. Continental A75, Wood Prop
    B. Long Fuselage
    C. Currently weigh 260 . 6’0” tall.
    D. Lightest pilot ~ 160 lbs.
    E. Fuselage nose tank. 18 gal.The center is 8″ behind firewall.
    F. Stits Polyfiber fabric.

    Note: It has a Matco tailwheel. I bought this airplane and did not build it. I placed 75 lbs of ballast in the front cockpit to ensure good CG with only 2 gals of fuel. I based this on the submitted W&B in which I have since found many discrepancies. I don’t care so much about being able to carry passengers as about carrying me safely. If that requires sacrificing passengers or light pilots, I’m fine with that.
    I currently have the wings off and this is a good opportunity to correct CG issues. Also, feel free to share my results if it would prove beneficial.

    Thank you.

    Chris Pirrmann.
    BTW, I’m not worried about Cameron Diaz. Morgan Fairchild however …..

    • Chris Pirrmann says:

      I forgot to mention that the empty weight is reported as 695 lbs. Don’t know if you need that or not.

  6. Working on it this weekend post hurricane

  7. Mark Roberts says:

    Here’s the info on my build:

    (A) The type of engine and the proposed propeller.Corvair 110 HP with Wooden prop. Not sure the weight of a wooden prop but I bet you will know the rough estimates.

    (B) Length Of fuselage:I lengthened the fuse nose from the junction of the front wing strut by 2″ for some relief from the tail heavy condition already. It measures 18.5″ from where the front strut connects to the fuse to the front of the fuse.

    (C) The Pilot’s weight:
    On average I am now 225-220 dressed and ready to fly. For what it’s worth, first thing in the morning I’m 205-ish, so I am guessing with a flight jacket on a cold morning and gear I’d be in the 220-ish range.

    (D) The range of pilots weights:I will most likely be the largest guy to fly. BUT, if there is an opportunity to broaden the range it will be good. 230-240 total pilot weight?

    (E) Fuel Tank Location(s) and capacities:
    Expert advice needed here. I have yet to make any arrangements for the tank, so your advice will be followed. I plan to use the Corvair 110 HP conversion with strict adherence to all building advice you give, so where and what you recommend will be followed. I prefer the tank to be in the front of the fuse as opposed to in the wing UNLESS you advise otherwise. I prefer it in front as opposed to over my head.

    (F) Unusual features:
    I tilted the pilot seat an extra 2″ back from the plans at the top of the seat – from 31″ as shown on the plans to 33″. I have long arms so I didn’t want to be right on the instrument panel and feeling cramped, BUT I know this was probably negating my 2″ of added fuse length forward of the cabanes.

    I also deepened the fuse 2″ from the plans so I would sit lower in the fuse. I am 6′ 4″ and was afraid to stick out too far in the finished plane. I don’t believe that will affect the W & B, but I am uneducated in what actually matters so I include it here in case.I widened the fuse 2″ from 24″ to 26″ for my larger frame.

    As mentioned earlier, I lengthened the nose 2″ forward of the front cabane struts to help with tail heaviness.

    My current “Hat Box” is open all the way to the first bulkhead behind the pilot seat but I do not plan to have anything heavy beyond an extra headset for the front passenger.

    I have built in the passenger door per the plans from Keri-Ann Price.

    I HAD planned to extend the wings by 2-4′ total (for a wingspan of 33′) to help give me better wing loading for my size (and connect the wing struts out one bay to compensate for the added wing span per side). But this was only dreaming at this point as I didn’t want to do something structurally like this without knowing if I was creating a safety problem with the spars. This also would have meant I would be adjusting the tail area to match the larger area. This is beginning to get into more changes than I feel able to justify with my limited aeronautical engineering skills, but could bear on the discussion here. Additional weight behind the wing perhaps 3-4 pounds with the added area?

    I plan to build the steerable tail wheel per plans from Keri-Ann Price. Additional weight of this addition unknown over original skid. 

  8. Wayne Schroeder says:

    A=Corvair
    Warp drive
    B= 172.75
    C= 5’11” 290
    290 me-150ish
    E= fuselage tank
    13gallons
    Center of tank 8″ aft of fw
    F= matco steerable Tailwheel
    Seat back to fw 76″
    Stewart’s fabric and paint

  9. Chuck Byrer says:

    Thank you for all the work you have done on Pietenpol weight and balance. Being the proud third owner of a GN-1 with a bogus weight and balance record I find myself in need of your generous offer to help me correct my imbalance problem. Following is the data I have collected: (A) Continental A75 engine, wood prop (13.2 lb w/hub),hand prop start. (B) Long fuselage, 170 1/2″ front face of firewall to rear of tail post. (C) My flying weight is 188 lb. in the summer, 192 lb dressed for winter, 5′ 7″ tall.(D) About average weight of those who might fly it. (E) 16 Gal. tank in the fuselage @ -5″ Arm or 11 3/4″ behind front face of fire wall.13 Gal. wing center tank. Tail wheel/spring arrangement weighs 8.3 lb. Tail wheel was used for weigh point and is at 165″ arm (181 3/4″ behind front of fire wall. I do not have a set of Grega plans to determine seat back tilt but the CG of the pilot (Me) calculates to 52″ behind the Datum (Wing LE) or 68 3/4″ behind fire wall face.
    Thanks Again
    Chuck Byrer
    Thorndale, TX

  10. Bryce Gorrell says:

    A. CorvAIR with Warp Drive, Sheradin cowl, spinner.
    B. Long (1994 corrected)
    C. 5’9”, 225 currently, but want to have room for “growth,” might be 250 by my first flying season.
    D. My daughter will likely start flying at age 17, maybe at 140 or so. The max might as well be similar to Kevin P’s.
    E. Fuel tank will be center section only, similar to Earl B’s.
    F. Aft seat back leaned back 2” from plans, aft seat bottom lowered 1” from plans, will install molded plastic bucket type boat seats over the plywood seats, steel gear, wheel pants.

    • Bryce Gorrell says:

      F. I want to strengthen the forward turtle deck support structure to allow sitting on it for ingress/egress. Something like 3 equally spaced arches of 1/4″ ply under a 4″ wide band of 1/4″ ply bent around on the outside, similar to what I saw on Kevin P’s.

      Also, minimal glove box in aft cockpit, but baggage compartment in front of forward “instrument board,” up to firewall. I plan to use the “shelf” for the Model A engine mount as the bottom of this box with the sides formed by the large gussets, up to the top of the semicircular “roof.” I’d guess it will hold 2 moderately sized backpacks (perhaps 30 pounds max), with the CG between 7 and 15″ behind firewall.

  11. Ron Turner says:

    A-continental a65-8F w/metal prop hand prop B-168 inches C-5′ 8″ 174lbs. D-150/200 lbs. E-Center section 13 gallon tank F-Main wheels center is .5 inches aft of datum / total weight w/6 gallons of fuel is 744 lbs.

  12. Chuck Beyer says:

    Hi William,
    Thank you again for all your great work on the weight and balance manual! I plan to incorporate all of the recommendations in your book. They just make good sense!
    As we talked about, I purchased my GN1 project from a friend of the original builder, Don Brooks.
    Below is the information you requested as the plane sits right now, plus I’ll text you some photos.
    Thanks again, Chuck

    A) Continental C75-12F (with starter, generator and flanged crank for prop)
    74″ wooden prop.
    Odyssey PC680 lead battery mounted on the firewall inside the engine compartment , weight
    with bracket: 16.5 lbs.

    B) Long fuselage: 171″ (Firewall to tail post)
    Width: measured from the center of the longerons at the rear cockpit seat back location
    = 25.25″

    C) Pilots weight: 195 lbs fully dressed. 5′ 9″ tall.

    D) Range of Pilots weight: 140 – 220 lbs.

    E) 12 gallon aluminum fuel tank, with the center of the tank 8″ aft of the front face of the firewall.
    Also, a 6 gallon aluminum auxiliary fuel tank located above in the center section of my 3 piece
    wing.

    F) A Maule steerable tail wheel. Cub style landing gear with 8.00-4 Goodyear tires. I plan to
    install hydraulic brakes.

    Additional dimensions using the acronyms in your manual:

    MML: 32.25″

    MGL: 8″ aft.

    PSL: 81.75″

    WL: 16″

  13. Cy Mao says:

    Hello,

    I hope this is the right place to ask this. I apologize if your “comments” are not where you want this. If you prefer an email address to be used just tell me.

    I want to build a Pietenpol in Thailand where a two seat ultralight can weigh 550 pounds empty. “Real airplanes” are very restricted in flight, sort of like flying IFR in the USA. Not so much fun. Ultralights can fly without being in constant radio contact with “our ATC”.

    I saw in the 1932 Flying and Glider manual that a Piet weighs 625 pounds with water with a Model A of 244 pounds and radiator of 21. Take away 265 and add back an A65 of about 170 and it weighs 530 pounds which is legal by 20 pounds. This is my plan. Then I research this plane on the forum and see that this plane usually weighs over 700 pounds and I think it is due to a lot of changes by builders since 1932 likes batteries and brakes and such.

    So I ask if you can help me build the lightest Pietenpol and if you think it can weigh 550 pounds or less. Then of course we will talk about CG – I watched your video about this too.

    I prefer build wood fuselage. Is the metal version lighter? I can build steel if necessary.
    What is lightest gear? I think old wooden gear looks lighter.
    My place to build is not 30′ so I must build 3 piece wing. But if this adds too much weight I can look for a bigger place to build if this is important.

    I plan only Airspeed indicator and oil pressure gauge.
    No brakes, no battery, no radio. No upholstery, Only seatbelts.
    You say always best to build long fuselage. Is this true even if empty weight is critical?
    I like to have steerable tailwheel but can change to skid when finished if I need to lose a pound or two (but skid vs tailwheel may affect where I should have put the axle a bit to handle on the ground, and will move CG a bit also.)

    I read about Oratex fabric that needs no heavy paint. I can use this. Some people say paint of airplane can weigh 30 pounds.

    Do you think 550 pounds is possible?

    If you think this is not possible by the plans then I wonder more:

    Looking at other airplane plans I always see ribs built from 1/4 x 1/4. Piet uses 1/4 x 1/2. Is this important or only overbuilt? 1/4 x 1/4 can save almost half the weight of ribs (gussets still weigh the same of course) Rib spacing is close as any other plane and wing loading is very light. Do ribs need to be 1/2″ for some other reason? I don’t see much compression struts in Piet wing and wonder if they also serve this function and best to leave at 1/4″ x 1/2″

    Also I notice fuselage longerons are 1″ x 1″ but many plans I look at make 3/4″ x 3/4″ much more common. Is this an example of rough landing areas in 1932 and not important anymore or is this not a good idea to make these smaller? Of course I don’t want a plane that will break apart.

    Thank you

  14. Friend, I gave your letter its own story, look at the top of my Blog under “Pietenpol for Thailand”

  15. Chris Pirrmann says:

    Is this project still alive or has it been shelved for now?

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