8KCAB airframe plans

LoLPilot

LoLPilot

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LoLPilot
For an academic exercise, would anyone have (or know how to acquire) plans for a 8KCAB airframe?
 
I'd talk directly to American Champion, You'd be surprise they may help. or at least tell you where to go. :)
 
LoLPilot said:
Because I thought we might have some mechanics here who knew for sure if and where they could be procured.
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Just to clarify: are you looking for the "blueprints" for an 8K? If so, rarely does a mechanic use them and they're not something you'll see every day. Now if you can use drawings from a different aircraft you have this as an option:
http://www.supercubproject.com/drawings/
 
Bell206 said:
Just to clarify: are you looking for the "blueprints" for an 8K? If so, rarely does a mechanic use them and they're not something you'll see every day. Now if you can use drawings from a different aircraft you have this as an option:
http://www.supercubproject.com/drawings/
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Yeah I’m looking for the blueprints needed to assemble the frame for a fuselage. I’ve emailed ACA to ask if I could buy them. I will not be surprised if I hear “NO” or don’t get a response, but it costs nothing to ask.

With the knowledge that an E/AB Super D clone doesn’t exist - yet that is the aircraft that perfectly fits what I think my mission is - I am evaluating the Grinch alternative. “If I can’t find a reindeer, I’ll make one instead.”
 
Bell206 said:
Maybe look around for an 8K going through a restore and make your own plans? I've seen a number of E/ABs born that way.
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That's really not a bad idea. Like try to find one going through a recover and ask if I can take measurements and make a drawing?
 
If American Champion applied for a patent for the model, The patent office will have prints.
 
Tom-D said:
If American Champion applied for a patent for the model, The patent office will have prints.
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Would it be them or Bellanca that would actually be the patent holder? ACA bought the TC and is producing them but the Decathlon was a Bellanca creation I believe.

That's the other thing that I do want to ask. Say they said "Sure, pay us $500 and we will give you a set of plans." If the design is patented can I legally build it, considering that they are still building the aircraft? I know that there are a fair number of Cub clones running around but it seems that each of them has differences from the original J3/PA11/PA18 that it was based on, which I assume is partially for patent and copyright stuff. But if it's for personal use I suppose it wouldn't make any difference....
 
LoLPilot said:
Would it be them or Bellanca that would actually be the patent holder? ACA bought the TC and is producing them but the Decathlon was a Bellanca creation I believe.

That's the other thing that I do want to ask. Say they said "Sure, pay us $500 and we will give you a set of plans." If the design is patented can I legally build it, considering that they are still building the aircraft? I know that there are a fair number of Cub clones running around but it seems that each of them has differences from the original J3/PA11/PA18 that it was based on, which I assume is partially for patent and copyright stuff. But if it's for personal use I suppose it wouldn't make any difference....
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You can only ask.... and cry about the answer,
 
LoLPilot said:
Would it be them or Bellanca that would actually be the patent holder?
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I doubt there would be a patent on the entire aircraft as the Wright Bros and Glenn Curtis fought over this in the early 1900s. There might be parts of it filed for the 8K but I wouldn't hold your breath. But if you want to look: https://www.uspto.gov/patents-application-process/search-patents
LoLPilot said:
But if it's for personal use I suppose it wouldn't make any difference....
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Correct. So long as your's is not an exact copy and you do not try directly connect it to the actual 8K there is zero concern--even if you wanted to sell it. And there is really no copyright issue as you can't copyright names or ideas. Unless Piper had trademarked the use of the term "Cub" anyone can use it on their aircraft. Majority of the aircraft out there, certified or not, are off-copies of some previous aircraft or piecemeal from a group of aircraft designs.
 
LoLPilot said:
If the design is patented can I legally build it, considering that they are still building the aircraft? I
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Patents don't last very long... certainly not as long as 8KCAB's have been built for. So certainly there are no current patents on the design.
 
Surprise surprise, they said no. If I want them I'll have to get creative.
 
The National Air and Space Museum has many drawings for many different aircraft. You can send a request to them to pull the drawings. I once asked what information they had on the BV-141 and they came back with a list of thousands of pages of drawings and other documentation. For a few cents per page they would have sent me all those documents.

https://airandspace.si.edu/research/resources/reference-services

https://airandspace.si.edu/collections/archival-collection/technical-reference-files
 
mondtster said:
How would someone repair a rusted or bent fuselage without data?
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FYI: The 8K has a service manual which directs you to AC43.13-1. Same as the Super Cub but it references the previous Civil Aeronautics Manual 18. But unlike the 8K the Cub drawings are in the public domain and available for pay or free.
 
LoLPilot said:
If I want them I'll have to get creative.
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Maybe get copies of the service and parts manuals and start your design from those. If I recall there is a decathlon or similar .org site that has the manuals free. Then find a disassembled 8K and add specific dimensions to your drawings?
 
Thanks guys. They said that they have a shop to repair damaged airframes which is why they don’t allow drawings outside.

I’ll check some of those other resources. For what it is worth, is it possible to modify a SC fuselage to have similar capabilities as a Decathlon?

I’ve decided my “perfect” aircraft: CAN operate from grass but doesn’t have to be a STOL plane. Can do gentleman’s acro. I’d like to learn and practice basics but don’t have an interest in doing a bunch of negative G stuff. CAN do a weekend trip with two people who pack judiciously. Not looking for a touring plane but I’d like to be able to take it to the lake for a weekend so I’d like 172-ish Cruise speeds anyway.

If a SC can be made to do all of those that seems like the path of least resistance.
 
Why not buy a Decathlon/Citabria/Scout instead of going through this mess?
 
Bell206 said:
Define modify?
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See below - create a Super Cub based aircraft that has similar basic acro abilities to a Super D.

Mtns2Skies said:
Why not buy a Decathlon/Citabria/Scout instead of going through this mess?
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Because I hate having to pay not-inconsiderable sums of money for pieces of paper (and go through the trouble of finding said pieces of paper) if I want to make changes to it.
 
LoLPilot said:
Because I hate having to pay not-inconsiderable sums of money for pieces of paper (and go through the trouble of finding said pieces of paper) if I want to make changes to it.
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But you're clearly going through way more trouble just to get what you want.
 
Mtns2Skies said:
But you're clearly going through way more trouble just to get what you want.
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I'm willing to go through that trouble on the front end to avoid headaches down the road. For instance, look at Garmin G5 systems. The cost for the Experimental G5 is hundreds less than the STC'd version. The SkyBeacon is the same way, and the SkyBeacon was an available ADS-B Out solution for the Experimental world before it was available in the Certified world. I've thought of buying a Citabria because (let's be honest) a 7ECA would almost perfectly fit what I am looking for, but I'm not interested in jumping through the hoops of Certified aircraft maintenance to keep such a simple craft in airworthy condition. I'd rather be able to just make changes I want to make to it in terms of things like lights, instrumentation, and avionics.
 
LoLPilot said:
I'm willing to go through that trouble on the front end to avoid headaches down the road. For instance, look at Garmin G5 systems. The cost for the Experimental G5 is hundreds less than the STC'd version. The SkyBeacon is the same way, and the SkyBeacon was an available ADS-B Out solution for the Experimental world before it was available in the Certified world. I've thought of buying a Citabria because (let's be honest) a 7ECA would almost perfectly fit what I am looking for, but I'm not interested in jumping through the hoops of Certified aircraft maintenance to keep such a simple craft in airworthy condition. I'd rather be able to just make changes I want to make to it in terms of things like lights, instrumentation, and avionics.
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There are waay waaaaay less hoops than you think there are.
 
Mtns2Skies said:
There are waay waaaaay less hoops than you think there are.
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My experience thus far has been watching some of my friends' experiences. One had a broken exhaust bolt turn into an overhaul of an otherwise good engine because of a service bulletin regarding an oil leak. Another abandoned hope of taking the vacuum system out of his plane because of the cost of complying with the STC's available to fit electronic attitude and heading indicators in his plane. I'm aware of "hangar fairies" as people on here have put it, but when dealing with a federal entity I'm unwilling to try and skirt what they want me to do. I'll drive a not-strictly-road-legal car because if they decide to bust me it gets impounded. But I don't want to give a federal agency the opportunity to make an example out of me if they decide that they want to crack down on scofflaws.
 
LoLPilot said:
My experience thus far has been watching some of my friends' experiences. One had a broken exhaust bolt turn into an overhaul of an otherwise good engine because of a service bulletin regarding an oil leak. Another abandoned hope of taking the vacuum system out of his plane because of the cost of complying with the STC's available to fit electronic attitude and heading indicators in his plane. I'm aware of "hangar fairies" as people on here have put it, but when dealing with a federal entity I'm unwilling to try and skirt what they want me to do. I'll drive a not-strictly-road-legal car because if they decide to bust me it gets impounded. But I don't want to give a federal agency the opportunity to make an example out of me if they decide that they want to crack down on scofflaws.
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Okay well if you're so adamantly certain of this, then just find an experimental that already exists that you like. That'd be way more effective than trying to do this charade. Get one of the RV models, should tick all your boxes.
 
Wag aero sells plans for their cubby with a clipped wing plans supplement. It want be as capable as an 8k but probably as capable as you would need for Sunday aerobatics. They can hold a 150 hp engine so with the lighter weight should be a decent performer.
 
LoLPilot said:
create a Super Cub based aircraft that has similar basic acro abilities to a Super D.
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Try looking at some of the Super Cub kits by Dakota, Bearhawk, or Back Country. Or on the smaller side one of the Wag Aero kits. The only issue you may run into is on the aerobatic side. As part of your research try to determine early who will be issuing your AWC: DAR or ASI. While there are no E/AB aircraft building requirements for aerobatic, most Ops Limitations usually prohibit aerobatics unless the aircraft has history in that type of ops. So by dealing with DAR up front you'll have a better chance at picking the right aircraft that will give all your requirements and the Ops Limits that allow it.
 
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Other that a couple of tubing size changes, the decathlon fuselage is identical to the Champ's. The National Aeronca Association will sell you a complete set of Champ drawings for just a few bucks and most of the upgrades are noted in the drawing revisions.
 
Bell206 said:
. .most Ops Limitations usually prohibit aerobatics unless the aircraft has history in that type of ops. So by dealing with DAR up front you'll have a better chance at picking the right aircraft that will give all your requirements and the Ops Limits that allow it.
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Not correct. You the builder are responsible for determining the aircraft's aerobatic capabilities in Phase 1 flight test. Make appropriate logbook entries and the aircraft is OK to perform those maneuvers going forward.
 
kyleb said:
Not correct.
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Interesting. I know 2 individuals that a DAR would not permit aerobatics unless they could show calculated g-loading on the wing. Could that have been a personal thing for the DARs or is there some sort of guide they follow for Phase 1?
 
Bell206 said:
Interesting. I know 2 individuals that a DAR would not permit aerobatics unless they could show calculated g-loading on the wing. Could that have been a personal thing for the DARs or is there some sort of guide they follow for Phase 1?
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Sounds like an individual DAR preference. I've built and registered one aerobatic EAB, have been a Tech counselor for 20 years, and have been active in the experimental world for 25 years and it hasn't come up once.

If DAR's were routinely asking for that, I'm pretty sure I'd know about it.

Now, in the U.K., they want a stack of documentation, but not here.
 
kyleb said:
Sounds like an individual DAR preference.
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So in the case of a kit build, if the original prototype was not built with aerobatics in mind, there should be no issue to add aerobatics to the Op Limit provided it demonstrates that ability in Phase 1?

And if you don't mind while we're here, how does 91.303 Aerobatic Flight and 91.307 Parachutes fit into Phase 1 testing and general ops for E/AB?
 
Bell206 said:
So in the case of a kit build, if the original prototype was not built with aerobatics in mind, there should be no issue to add aerobatics to the Op Limit provided it demonstrates that ability in Phase 1?

And if you don't mind while we're here, how does 91.303 Aerobatic Flight and 91.307 Parachutes fit into Phase 1 testing and general ops for E/AB?
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Below are the generic operating limits as published by the FAA. One note is that most operating limits are amended to say WTTE "Cannot operate IFR or at night unless properly equipped". There are no aerobatic limitations other than "The aircraft is controllable throughout its normal range of speeds and throughout all the maneuvers to be executed" You document those maneuvers during Phase 1 testing.

https://www.ecfr.gov/cgi-bin/text-i...f2d39c55&mc=true&node=se14.2.91_1319&rgn=div8

I do not think there are any differences in the rules around aerobatics in an experimental vs a certified aircraft. If you have a passenger, both need to be wearing chutes. Solo, no chute is needed. The airspace rules don't change.
 
What about a Rans S-21? In thebearly stages it was designed with I think greater than 6G. I asked if it would be aerobatic and they didn’t know at that time. I never followed up. Maybe that would be an option?
 
At one time, an initial set of op limitations were issued when the plane was initially signed off for phase 1, and another updated version at the completion of phase 1. If no acro was demonstrated during phase 1, the phase 2 limitations would say no acro. Nowadays, you get one set of limitations, with verbage like "only those maneuvers demonstrated in phase 1 may be performed during phase 2."
 
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