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Thread: What to add modifications to L-21B

  1. #1
    cubnut93's Avatar
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    What to add modifications to L-21B

    I helped a friend restore a L-21B several years ago. He is now selling the airplane and he has a possible buyer who wants him to have some modifications made to the airplane.

    The mods are as follows:

    Increase Max GW to 2000lbs

    Install a Borer 8242 climb prop

    Install belly pod

    Install bush wheel & tires



    The airplane has had the following mods already installed:

    Modified PA18-135 as follows:

    Engine O320-A2B STC SA00522SE Cub Crafters (Install 150hp Engine)

    Engine 0320-A2B STC SE00252SE Ly Con (Boost Engine to 160hp)

    Increased Max Gross Takeoff Weight to PA18-150 Weights(1750lbs) SA292AL-M.R. Borer

    3 inch Extended Main Landing Gear - SA02152AK Atlee Dodge

    3 inch Extended PA18 Type Main Landing Gear and Extended Shock Strut Assemblies
    SA02188AK Atlee Dodge

    Install Fuselage Top Deck X Brace STC SA02011AK Atlee Dodge


    There may be other mods that were installed when the airplane was restored in 2014, but the owner needs to check into that.


    My question is: What needs to be done in order to install the mods listed above?
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  2. #2

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    I'd tell the guy if he wants all that done, he can pay to have it done after he buys the plane. Theres a pretty good chance that he'd back out of the deal if your friend was doing all the mods before the sale was finalized.

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    I don't think the wheels, belly pod (depending on which one) or prop would be much of an issue. Just money to buy the items with an STC. The STC for the 2000 lb. gross weight is specific to a PA-18-150. With your current 1750 gross weight upgrade your issue now are the PA-18-135 wings. PA-18-150's have different wings. What model year is the PA-18-135? How many ribs are in the wings? You could get a field approval for the 2000 lb. GW if the airplane meets the type design of a PA-18-150.

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    mvivion's Avatar
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    Quote Originally Posted by bubb2 View Post
    I don't think the wheels, belly pod (depending on which one) or prop would be much of an issue. Just money to buy the items with an STC. The STC for the 2000 lb. gross weight is specific to a PA-18-150. With your current 1750 gross weight upgrade your issue now are the PA-18-135 wings. PA-18-150's have different wings. What model year is the PA-18-135? How many ribs are in the wings? You could get a field approval for the 2000 lb. GW if the airplane meets the type design of a PA-18-150.
    The 2000 pound GW STC applies to all the Piper SC wings, including 13 rib wings.

    I'd agree, tell the buyer to install all that stuff himself, or, if for example, he lives somewhere there's no good SC type workmen, tell him to buy the plane, and you'll refer him to a mechanic local to you to do the work prior to him picking it up....on his nickel, of course.

    No way would I pay to have all that stuff done FOR him, unless he writes the check for the done deal, up front.....no take backs.

    MTV
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  5. #5

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    Quote Originally Posted by mvivion View Post
    The 2000 pound GW STC applies to all the Piper SC wings, including 13 rib wings.

    I'd agree, tell the buyer to install all that stuff himself, or, if for example, he lives somewhere there's no good SC type workmen, tell him to buy the plane, and you'll refer him to a mechanic local to you to do the work prior to him picking it up....on his nickel, of course.

    No way would I pay to have all that stuff done FOR him, unless he writes the check for the done deal, up front.....no take backs.

    MTV
    I would appreciate you sharing your data on the 13 rib wings. It would be a great benefit as it's my understanding a field approval would be required to install the 2000 lb. kit in a PA-18-135. My IA tells me the STC is specific to PA-18-150's and according to the PA-18 parts book no PA-18-150 was ever made with 13 rib wings. Hard data would limit the questions from the FAA on a field approval request. Wips data is a bit confusing or maybe misleading as it addresses fuselage up-grades. and minimum horsepower. Not only is the STC specific to PA-18-150's so are the Flight Manual Supplements (except for some reason they have a Flight Manual Supplement for PA-18-135 and PA-18-150 @2000lbs when on Wip 2100's).
    Last edited by bubb2; 04-12-2021 at 05:50 PM.

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    mvivion's Avatar
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    Some folks on this thread didn’t have a problem: https://www.supercub.org/forum/showt...eight-increase

    i know of at least three Super Cubs with 13 rib wings with the kit, and legal. It is important to know that the subject airplane MUST have been converted to PA-18-150 configuration, including the gross weight increase to 1750 lbs BEFORE the 2000 pound GW kit can be installed.

    perhaps Ms Amy from Wipaire will check in here, though she may be in Sun N Fun

    MTV

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    Iíve done several 2000lbs kits on 13rib wings, the stc covers all PA-18 and even the pictures in the stc drawings are a 13rib wing. You still have the lower VNE of 138 though.
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  8. #8

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    Quote Originally Posted by PA-22/20-160 View Post
    I’ve done several 2000lbs kits on 13rib wings, the stc covers all PA-18 and even the pictures in the stc drawings are a 13rib wing. You still have the lower VNE of 138 though.
    Did you get a Field Approval to install the kit on a different model? I agree the contents of the STC indicate all you need is minimum 150 hp and 1750 gw but the STC is specific to PA-18-150. Please let me know how you determined it's allowed in al PA-18's. I'm not doubting you, but I'm looking at the STC now and it only list's PA-18-150 aircraft as the approved aircraft model.
    Last edited by bubb2; 04-12-2021 at 10:51 PM.

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    Quote Originally Posted by PA-22/20-160 View Post
    Iíve done several 2000lbs kits on 13rib wings, the stc covers all PA-18 and even the pictures in the stc drawings are a 13rib wing. You still have the lower VNE of 138 though.
    I am interested to learn more about the Vne limitations. I have what was originally a 1951 L-21A. It now has Dakota Cub wings (new in 2007), 160hp, the 1750 GW increase, and lots of other mods. What speed is the higher Vne and what is all required to have it?

    Thanks

    Jeff

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    The PA-18-150 16rib wing has 153vne, don’t know if you can up your speed or not but it’s really a moot point.
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  11. #11

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    Quote Originally Posted by bubb2 View Post
    Did you get a Field Approval to install the kit on a different model? I agree the contents of the STC indicate all you need is minimum 150 hp and 1750 gw but the STC is specific to PA-18-150. Please let me know how you determined it's allowed in al PA-18's. I'm not doubting you, but I'm looking at the STC now and it only list's PA-18-150 aircraft as allowed aircraft.
    You’d be best to call wipaire and get it straight from the hoses mouth.

  12. #12

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    Quote Originally Posted by PA-22/20-160 View Post
    The PA-18-150 16rib wing has 153vne, don’t know if you can up your speed or not but it’s really a moot point.
    Wonder if you could get a cub going that fast in a decent with a long prop, bushwheels and uncovered gear? You must be able to?

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    Quote Originally Posted by jrussl View Post
    I am interested to learn more about the Vne limitations. I have what was originally a 1951 L-21A. It now has Dakota Cub wings (new in 2007), 160hp, the 1750 GW increase, and lots of other mods. What speed is the higher Vne and what is all required to have it?

    Thanks

    Jeff
    The FAA Approved Flight Manual for the aircraft model will list all airspeed limitations except for those superseded by an approved Flight Manual Supplement. This can get complicated by cubs that have been modified to the extent that they now are now basically a different model with multiple Flight Manual Supplements. Can you get to Vne in a cub?

  14. #14

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    Quote Originally Posted by PA-22/20-160 View Post
    You’d be best to call wipaire and get it straight from the hoses mouth.
    I did. He could not answer the question. More coming I hope.

  15. #15
    daedgerton's Avatar
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    Find a new buyer... This is the type of buyer that will never go away...

  16. #16
    Utah-Jay's Avatar
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    Damn nice looking plane, I doubt it would be hard to sell

  17. #17

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    I know 2 buyers looking for nice Cubs....they won’t play games like that, understand the current market and have cash. If he falls through let me know.

  18. #18
    Steve Pierce's Avatar
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    Quote Originally Posted by KevinJ View Post
    Wonder if you could get a cub going that fast in a decent with a long prop, bushwheels and uncovered gear? You must be able to?
    Maybe straight down with your hair on fire.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers
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  19. #19
    Cub junkie's Avatar
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    What a beautiful Cub. I think the best thing for it is to go to a new caretaker that appreciates it as it is.

  20. #20
    hotrod180's Avatar
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    153 Vne, no problem hitting that....if it's in kph
    Cessna Skywagon-- accept no substitute!

  21. #21
    cubdriver2's Avatar
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    Quote Originally Posted by KevinJ View Post
    Wonder if you could get a cub going that fast in a decent with a long prop, bushwheels and uncovered gear? You must be able to?
    I know a 790lb Pa11 will go 140 mph when you fall out of a roll

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"

  22. #22

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    a Cub is like an A6....Vne is LBA. Limited by airframe.

  23. #23

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    If you have a 160 hp cub the 8242 is just a bit flat for that unless you are working it hard. a 43 or 44 would be better for most use.
    DENNY

  24. #24

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    Yes Sir I would be interested in talking with your prospects. I dont think this guy has the money to pay for all these modifications. The airplane is located in North Carolina but I would deliver to Alaska. Asking $140 but have 200K in it. Planned to keep it so spared no expense. Fred Vacarro and I worked on this one for three years. My phone is 828-231-7758.

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    This prospect wants a climb prop on it. What do you think would be the best prop?

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    Quote Originally Posted by L21BGUY View Post
    This prospect wants a climb prop on it. What do you think would be the best prop?
    The one thatís on it.

    also, itís a sellers market right now - no sense in getting in bed with a demanding buyer.
    Likes 1934A liked this post

  27. #27

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    Quote Originally Posted by PA-22/20-160 View Post
    I’ve done several 2000lbs kits on 13rib wings, the stc covers all PA-18 and even the pictures in the stc drawings are a 13rib wing. You still have the lower VNE of 138 though.
    Based on the STC, the applicability is only PA-18-150, PA-18A-150, PA-18S-150, and PA-18AS-150. The only way to legally install it on another model is with additional approval (either Field Approval or DER approval). Somehow you have to come up with a deviation to the STC to get another model.
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  28. #28

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    Quote Originally Posted by L21BGUY View Post
    This prospect wants a climb prop on it. What do you think would be the best prop?
    I agree with Akwing... If the prospect wants a change that's the prospect's issue - not yours. Now you didn't SAY you were thinking of changing it so they'd buy, but that's what it sounded like ... But don't do it. As often as not the fish will flop and you're left out a big stack of cash and a bigger bill to put it back right. Voice of experience here. You have one of the most marketable quantities on the current market. Wait for the easy - and safe sale. It will come.

    I also remember people trying to put their preferences on the seller. How often have we all heard, "I want to put XYZ on it so you have to reduce the price by XYZ." Again don't do it. Sell your airplane, not the buyer's.

    Of course just my opinion and worth every penny you paid for it.
    Last edited by RedOwlAirfield; 04-28-2021 at 02:38 PM. Reason: errata
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  29. #29

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    Quote Originally Posted by RedOwlAirfield View Post
    I agree with Akwing... If the prospect wants a change that's the prospect's issue - not yours. Now you didn't SAY you were thinking of changing it so they'd buy, but that's what it sounded like ... But don't do it. As often as not the fish will flop and you're left out a big stack of cash and a bigger bill to put it back right. Voice of experience here. You have one of the most marketable quantities on the current market. Wait for the easy - and safe sale. It will come.

    I also remember people trying to put their preferences on the seller. How often have we all heard, "I want to put XYZ on it so you have to reduce the price by XYZ." Again don't do it. Sell your airplane, not the buyer's.

    Of course just my opinion and worth every penny you paid for it.
    Yes but good opinions are worth repeating and you guys nailed it. Politely (or impolitely if you wish, you owe him zip) tell your clueless prospect to go pound
    sand. He can do all the mods he wishes as his time and cash permit.
    I commend you on a fabulous restoration sir!!!


    Sent from my iPhone using SuperCub.Org mobile app

  30. #30
    daedgerton's Avatar
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    I paid $73K for my mid time 1955 "A" model 2 1/2 years ago... It now has 29" ABW's, Borer 82/44, FA Dodge Hot Rod Exhaust, FA Dodge Air Box, Trig ADSB, Dakota gauges and fuel selector, Brake Boosters and a few other mods... I really wish you were the guy selling it and would have considered "adding" all these upgrades at the $73K sales price!!!

    Put your Cub on Barnstormers and you'll get it sold sight unseen by a cash buyer in 7 days...
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  31. #31
    mvivion's Avatar
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    When I had a PA 11 for sale, a guy called who wanted more photos than I’d posted. I sent them. Then he wanted pictures of specific parts of the plane, which I took and sent. This went on interminably.

    Finally, after I’d literally spent hours on the phone and taking and sending pictures, he said he was prepared to make an off. His offer: I’d fly it to him, several states away, and IF he liked it, he’d give me a super low ball offer. If he didn’t like it, he’d offer to pay my gas to get home.

    I said goodby, and took the plane off the market. Guy was a total ass, with lots of free time, and I doubt he was ever serious about buying the plane.

    A week later a young man called and asked if he could come look at the plane...in the morning. Sure. He arrived at 9AM (from quite a ways off), with his Dad in their Bonanza, his mechanic for the pre buy and his flight instructor to fly it home with him.

    After the pre buy and a short demo flight, he handed me a certified check and left...with the Cub.

    The first guy sounds like your guy. When he calls back, tell him to go away. There’s someone out there who is seriously interested in your plane. Wait for that guy.

    Trust me.

    MTV
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  32. #32
    hotrod180's Avatar
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    I got one to top that.
    A buddy of mine had a plane for sale, listed in Trade a Plane.
    (this was a number of years ago, pre-Barnstormers & mayeb pre-internet)
    He got a call from someone out of state who was interested in buying it.....a collect call!
    "Will you accept the charges?"...."No."
    Cessna Skywagon-- accept no substitute!
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  33. #33
    mvivion's Avatar
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    Quote Originally Posted by hotrod180 View Post
    I got one to top that.
    A buddy of mine had a plane for sale, listed in Trade a Plane.
    (this was a number of years ago, pre-Barnstormers & mayeb pre-internet)
    He got a call from someone out of state who was interested in buying it.....a collect call!
    "Will you accept the charges?"...."No."
    Yeah, but at least that one didn't waste hours of the seller's time....

    MTV

  34. #34

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    I got one to top that.

    I had a plane for sale in the neighbouring state.
    I got a text saying “I will take your plane home and fly it until it sells”
    I replied “Sure, but give me a week or so to get a fuel card, I wouldn’t want you to be out of pocket!”

    I never heard from him again?
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  35. #35

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    Empty weight?


    Sent from my iPhone using Tapatalk

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