Project: Citabria 7 GCBCrebuilt in the experimental category

[Franky]

Hi everyone

I just joined this fantastic group, i'm buyin a 1976 Citabria 7 GCBC wich is all apart from my good friend Buzz Cola, the new kid on the bloc below.
I'm planning to rebuilt it in the experimental category, so i will have to modify it enough to fit it in that category, the bird have the wood spars, so this will be the first thing to go, i will rebuilt the wings with a set of spars from Nick Smith (BBI Aviation), the new wings will give me a wing span of 36' 6",
i will increase the flaps lenth and move the ailerons outboard to fit the new wings, thinking about vg's as well, maybe go with the Super Cub ribs to make it a Super Cub wings, it even crossed my mind to put the S Cub ribs on the inboard section of the wing and keep the Citabria ones ont the outboard section but for the moment, it's just an idea, i need to investigate that more seriously.

I also want to get rid of the steel landing gears and come up with a suspension type gears, with shocks hidden in the belly, i've got a few mores ideas but
for the moment, theses are the main modifications that i want to do, i want a good bush plane and be able to go where a Cub will go.

Comments are welcome.
Franky

[bob turner]

Might be cheaper to buy a Cub. You would also get to fly. Sounds like you are watching the 51% rule, but as I understand it, converting certificated aircraft to experimental is fraught with problems.

[Richgj3]

There are three “Experimental” categories. Experimental Exhibition, Experimental Flight Test and Experimental Amateur Built. I’m assuming you want the last one. There’s also Experimental LSA, but I don’t think that applies here. If you want EAB, then you will have to document for the FAA or DAR that is going to issue the AW Certificate showing you built at least 51% of the airplane. Doing this on a project which started life as a certified airplane could be a challenge. You should discuss this with a DAR before you invest too much time and money.

Rich

[G44]

What experimental category do you plan to take it into? What basis and how do you plan to do this? Sounds very expensive to me. With all the mods you are still going to have a Citabria, it wont be a Super Cub by any stretch of the imagination. Save yourself a lot of work, money and frustration and buy a Super Cub if that is what you want.

Kurt

[RaisedByWolves]

Are you sure it was a certified airplane? You said it was all apart. I would have to imagine that someone scratch built the fuselage while looking at a citabria, thus qualifying it for an experimental amateur built.


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[dgapilot]

There are three “Experimental” categories. Experimental Exhibition, Experimental Flight Test and Experimental Amateur Built. I’m assuming you want the last one. There’s also Experimental LSA, but I don’t think that applies here. If you want EAB, then you will have to document for the FAA or DAR that is going to issue the AW Certificate showing you built at least 51% of the airplane. Doing this on a project which started life as a certified airplane could be a challenge. You should discuss this with a DAR before you invest too much time and money.

Rich

Actually there are more than 3, there are 9. That said, many folks only think Experimental Amateur Built which requires the builder to complete the “major portion” of fabrication and assembly as determined by the FAA checklist https://www.faa.gov/aircraft/gen_av/...syCklistFW.pdf. Keep in mind that no work performed on parts that were salvaged from a previously certified aircraft can be used to meet the major portion for amateur built.

The real key here, why do you want an aircraft with an Experimental Certificate? Why don’t you want to restore it to a Standard Category Certificate? For each type of Experimental Certificate, 91.319 says an aircraft with an experimental certificate can only be operated “for the purpose for which it was Certificate.”


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[Crash, Jr.]

The real key here, why do you want an aircraft with an Experimental Certificate? Why don’t you want to restore it to a Standard Category Certificate?

Probably so he can mod and maintain his plane as seen fit without a pile of paperwork and a colonoscopy from the FAA every time. Certificated aircraft for recreational use are a dying breed with rising maintenance cost.

[dgapilot]

Probably so he can mod and maintain his plane as seen fit without a pile of paperwork and a colonoscopy from the FAA every time. Certificated aircraft for recreational use are a dying breed with rising maintenance cost.

There really isn’t a need for high costs. An owner can do almost all maintenance under the supervision of an A&P. Find a sympathetic A&P (better yet an IA) to work with you.

The only Experimental purposes that the owner can mod or maintain himself is Amateur built, and even there, he has operating limitations that specify if major changes as defined by 21.93, the FSDO has to be notified and receive a response before operations.

For any aircraft that was previously certified, and converted to Experimental, Part 43 still applies, so only certified mechanics can work on them, and major changes need approved data. Most people don’t realize this, read 43.1.


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[Franky]

There really isn’t a need for high costs. An owner can do almost all maintenance under the supervision of an A&P. Find a sympathetic A&P (better yet an IA) to work with you.

The only Experimental purposes that the owner can mod or maintain himself is Amateur built, and even there, he has operating limitations that specify if major changes as defined by 21.93, the FSDO has to be notified and receive a response before operations.

For any aircraft that was previously certified, and converted to Experimental, Part 43 still applies, so only certified mechanics can work on them, and major changes need approved data. Most people don’t realize this, read 43.1.


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Guys
You are totally right, you can not de-certify an aircraft and rebuilt it as an amateur built, however, you can used somes certified parts from an airplane to build an experimental or amateur built aircraft, in Canada, the rules say that you can used a welded assembly from a certified aircraft, it does not say that you can not used an airframe from a certified aircraft and then, you have the 51%rule to deal with.

It's been done before, but you have to play the game the right way, dont invite a DAR in your garage with a full airplane apart in it.

To answer somes questions, the Citabria is all apart because it have the wood spars and they need to be replace by a set of Milman aluminium spars, so the previous owner have decided to do a full rebuilt in the same time, but he bought a Super Cub kit and the Citabria project end up on the shelves.

I do not want a certified aircraft, i enjoy building and modifying things, i've been a machinist for a few years before coming to aviation, i will have more fun building an airplane than flying it, i already have 18,000 hrs of flying, mostly helicopters, so i've been to places where Super Cub can only dream of going. Yes a Super Cub would be my bush plane of choice but the Citabria is not a bad choice, specially at the price that i got it, no damages and complete, if i put a cub wing on it, it will be damn closed to what a Super cub can do, BBI Aviation is doing just that with their LS 3000 180, the airframe is based on a Citabria and have the Cub wings on it.

Franky

[DENNY]

Hi everyone

I just joined this fantastic group, i'm buyin a 1976 Citabria 7 GCBC wich is all apart from my good friend Buzz Cola, the new kid on the bloc below.
I'm planning to rebuilt it in the experimental category, so i will have to modify it enough to fit it in that category, the bird have the wood spars, so this will be the first thing to go, i will rebuilt the wings with a set of spars from Nick Smith (BBI Aviation), the new wings will give me a wing span of 36' 6",
i will increase the flaps lenth and move the ailerons outboard to fit the new wings, thinking about vg's as well, maybe go with the Super Cub ribs to make it a Super Cub wings, it even crossed my mind to put the S Cub ribs on the inboard section of the wing and keep the Citabria ones ont the outboard section but for the moment, it's just an idea, i need to investigate that more seriously.

I also want to get rid of the steel landing gears and come up with a suspension type gears, with shocks hidden in the belly, i've got a few mores ideas but
for the moment, theses are the main modifications that i want to do, i want a good bush plane and be able to go where a Cub will go.

Comments are welcome.
Franky

If you wat to to be able to go where a Cub will go. Spend your time and money on a Cub.
DENNY

[Franky]

A good pilot will land a Citabria where a poor pilot cant land with a Cub, now, you have to compare apples with apples, a 150 hp Super Cub with a Citabria 7 GCBC 150 hp at about the same weights, if the pilots are about the same level, the Citabria will be within 100/150 fts of the Cub, not 500 fts or more.

The Citabria is just too much of a good deal, there is no way i can built a Super Cub for what it will cost me to rebuild the Citabria, otherwise, i would definitely go for a cub, i've got a complete aircraft with engine (1000 hrs s/n) instruments, a prop, everything, i just need a set of spars, either from D&E in Florida or BBI Aviation in Ontario, Canada if i go experimental or a set of Milmans spars (4000.00 USD) if i decide to keep it certified, would also need to recover the whole plane and a paint job, wich i can do myself, but that's it, 500 to 700 hrs of building, versus 2000 for a new kit Cub.

[bob turner]

We were just trying to help. A Citabria simply cannot compete with a Cub for STOL operations. A good Mooney pilot can land shorter than a mediocre Cub pilot, but that is not a good comparison.

You will have a nice aircraft if you keep it stock with Milman conversion. Once you change the landing gear over to Cub-style you are in $$ territory. Get dga to tell you how much approval for that will cost.

Unless you are bound and determined to be an off-airport guy, your GCBC will be a nice aircraft. If you take it into the bush, you will need twice the runway a cub needs - 500 feet instead of 250 - if you like to take those kinds of risks.

[Franky]

We were just trying to help. A Citabria simply cannot compete with a Cub for STOL operations. A good Mooney pilot can land shorter than a mediocre Cub pilot, but that is not a good comparison.

You will have a nice aircraft if you keep it stock with Milman conversion. Once you change the landing gear over to Cub-style you are in $$ territory. Get dga to tell you how much approval for that will cost.

Unless you are bound and determined to be an off-airport guy, your GCBC will be a nice aircraft. If you take it into the bush, you will need twice the runway a cub needs - 500 feet instead of 250 - if you like to take those kinds of risks.

Ok Bob

If i'm able to built this thing in the experimental category, it will not be a Citabria anymore, it will be a copy of an LS 3000 180, go on the BBI Aviation website and check the specs for it and compare it to the specs of their Super Cub kit. The cost to fabricate a look alike Super Cub landing gear come down to the cost of the materiel to do it, as i said in my first post, i have a machinist background, i have a pretty well equipped garage and i have built
a Super Cyclone (copy of a 1954 Cessna 180 ) before and help built another one.



If i rebuilt it as a stock Citabria with the Milman spars, it will be for sale after, i'm not interested in a certified Citabria.

[skywagon8a]

Franky, You haven't said where you reside. Are you in Canada as your posts seem to indicate? All of the responses so far are applicable to aircraft in the USA. If you are in Canada, you do have a category which may apply here. Most of us are not familiar with those requirements and benefits.

It is possible to improve the performance of a 7GCBC to be very close to that of a PA-18.

[stewartb]

Get familiar with the 51% checklist and the points formula. Talk to guys who've done similar projects locally for advice on DARs. Have fun!

I love the E-AB category. I still have a certificated plane, too. E-AB offers a wide horizon and no fences. Certificated is like taking a shopping cart through a narrow aisle with glass jars on both sides. Freedom is more satisfying.

[stewartb]

Are you sure it was a certified airplane? You said it was all apart. I would have to imagine that someone scratch built the fuselage while looking at a citabria, thus qualifying it for an experimental amateur built.


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There's no difference in tallying E-AB points whether using a Citabria airframe or one from Javron. You can't claim fabrication points for either. And you don't need to.

[Franky]

Franky, You haven't said where you reside. Are you in Canada as your posts seem to indicate? All of the responses so far are applicable to aircraft in the USA. If you are in Canada, you do have a category which may apply here. Most of us are not familiar with those requirements and benefits.

It is possible to improve the performance of a 7GCBC to be very close to that of a PA-18.

I'm living in the Montreal area but i'm working in the UAE where i work as an offshore helicopter pilot, 1 more year and it will be retirement with all the time to built another homebuilt, like i said, building is my great satisfaction, i'm like Mike Patey minus the big wallet.

I know it is possible to improve 7gcbc to be very closed to a PA-18, the purists dont believe it but it's fine with me, it's still fun to debate about it, it's like
my father is stronger than yours when we were kids.

Yes there are a few things wich are different in Canada about homebuilt construction, the ideas are pretty much aligned with the ones from the FAA but the wording about it in a few cases, are differents, this is where we can put a foot in the door and give me the chances to do what i want to do with the Citabria, wich is to modified it the way i want, in the experimental category, yes it will be a lot of work but not as expensive as somes of the guys above think

That airplane have been apart on the shelves for 5-6 years, it would be a shame to leave it there.

[Franky]

There's no difference in tallying E-AB points whether using a Citabria airframe or one from Javron. You can't claim fabrication points for either. And you don't need to.

Man! you are so right about that, it is stupidity to think otherwise.

[brown bear]

I see your in Canada so this is not for you but here in the US builders should know that the
51% rule - Like so many things , is not always applied the same everywhere in the US .
Also so note it says salvaged parts from a type certificated aircraft , not from a EAB aircraft . An EAB does not have a "type certificate"
in this case the FAA is not talking about a new parts gotten from a kit manufacturer or, Airframs , Cubcrafters , or who ever even if they are PMAed.
Any way just know before you start what "your " FAA" will except.
Circular/AC_20-27G Go to page 11

https://www.faa.gov/documentLibrary/.../AC_20-27G.pdf
d. Use of Salvaged Assemblies from Type-Certificated Aircraft
2) You will not receive credit for work done on, or the use of, salvaged major assemblies or subassemblies when determining whether your amateur-built aircraft has met the major portion requirement. This would include any “rebuilding” or “alteration” activities to return these components to an airworthy condition

[skywagon8a]

I know it is possible to improve 7gcbc to be very closed to a PA-18, the purists don't believe it but it's fine with me, it's still fun to debate about it.

I installed slightly over sized tires 9:00-6, an 8046 prop and slightly extended wings with Ferguson droop tips on a 7GCB. It would perform as well as a stock PA-18 as measured by tracks in the snow.

[BC12D-4-85]

My 7GCBC 1978-87. Scout extended gear (heavy; now light aluminum is available), 80" C/S Hartzell prop, Victor Aviation massaged O-320, light electronics, small battery moved to adjust CG, extended rear baggage (fit 25 2x4's inside cockpit), Scout tail spring, Crosswinds STOL kit, extended wings w/Demer's tips, sealed ailerons, lower flap gap seals removed, 40* flaps, sealed elevators, weight about 1250# (heavy but still had stock interior and seating). T/O 50' longer than PA-18 I trapped with on skis, but flew 40 mph faster.

Gary

[RaisedByWolves]

Calling Jim crane. I wonder if he has seen this thread yet.


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[RoddyM]

My dad got us into flying. When I was barely a teenager, he bought a 1979 7GCBC and it was loaded with everything Bellanca had to offer including CAP 2000 floats and straight skis. A very nice plane. But I remember trying to convince him to buy a super cub, which he had flown previously. The “look” of the super cub was the thing for me at the time; like the cables running outside the wing along the strut and the landing gear. Course I didn’t know anything besides “looks” and it was his decision. I remember him clearly saying, “the Citabria is faster, the seats are more comfortable, it’s got a good heater, the interior fit and finish was nicer, and, it’s got toe brakes”. Those were his reasons, and, we have a 1,100 ft strip which is ample. My brother and I rode around in the back seat together some which worked because we were small and the rear seat was nice and wide. He paid about $35,000 Cnd for the Citabria. Imagine. About $23,500 US.
Today, he flies my brothers Super Legend which is loaded up with the creature comforts like the ‘79 Citabria had, but with outstanding take-off/climb performance.
All the best on your build Franky!

[MainlandCub]

A guy here in New Zealand has done something along the lines of what you are talking about, except he started of with a Champ, not a Citabria. He told me he basically built Scout wings for it. Power is an O-320 with a Borer prop. It has flown, but I haven't had a report.

Andrew.

[Crash, Jr.]

If rebuilding as experimental going with the Citabria landing gear would be pretty cool. The original suspension design is trash but you could easily modify it for PA-18 style suspension. Ernie Broten out of Willow designed a pretty cool air shock system that uses a calibrated orifice to control escaping air to slow shock travel. Pretty neat stuff.

https://www.airframesalaska.com/ABI-...eg-p/51035.htm

Haven't sold any yet but from handling the design and flight testing it looks pretty neat. Acme would be another option. Just really do anything except spring steel gear unless cruise speed is the main concern.

I'll agree that you can make a scout into a decent plane with enough money sunk into it. From where I stand though I'd rather spend that same amount of money on a cub. Plus I just think citabria/scouts are just hard on the eyes.

[bob turner]

I never cared for the appearance of early Champs, but Citabrias and Decathlons have wiggled their way into my pantheon of good looking airplanes. Form follows function, and these airplanes have definite function.
I own a Decathlon, and love it. A Cub it is not. A trainer? Lousy. But dollar for dollar, one of the best buys in aviation.

[BC12D-4-85]

One help for Champs is the Crosswinds kit. The Champ wing chord is 3" less than a Cub so the cuff adds back almost that. Locally there have been several 7GCBCs modified with extended wing tips from a Scout. They are lighter and look better than the droop tip mod I had in #21. It used a Cub end rib and heavy Demers tip, but at the time that was the only game in town.

I build a remote cabin with that plane in 1983-5. Flew an equivalent C-46 load of 14,000# of materials 50-90 miles depending on trip. Some inside the cockpit and the rest on floats. The extended wings and cuff helped. End of story and proof of product.

Gary

[RVBottomly]

If rebuilding as experimental going with the Citabria landing gear would be pretty cool. The original suspension design is trash but you could easily modify it for PA-18 style suspension. Ernie Broten out of Willow designed a pretty cool air shock system that uses a calibrated orifice to control escaping air to slow shock travel. Pretty neat stuff.

https://www.airframesalaska.com/ABI-...eg-p/51035.htm

Haven't sold any yet but from handling the design and flight testing it looks pretty neat. Acme would be another option. Just really do anything except spring steel gear unless cruise speed is the main concern.

I'll agree that you can make a scout into a decent plane with enough money sunk into it. From where I stand though I'd rather spend that same amount of money on a cub. Plus I just think citabria/scouts are just hard on the eyes.

Well, I've never seen that before. I was trying to come up with something similar. I would have thought the air shock cylinder would have to be bigger. With a small diameter like that, I figured pressures would have to be in the thousand pound plus range.

[BC12D-4-85]

Finally there's an alternative landing gear for pre-spring Champs. Especially on skis that gear would be great and replacing the oleo which needs maintenance would help keep them flying. Who knew? Spring gear works too but it takes length to achieve AOA and extra skills to keep it planted.

Gary

[Crash, Jr.]

Well, I've never seen that before. I was trying to come up with something similar. I would have thought the air shock cylinder would have to be bigger. With a small diameter like that, I figured pressures would have to be in the thousand pound plus range.

It's not actually an air spring doing the supporting. It works pretty much like a Piper bungee/hydrasorb unit except instead of using an oil shock it uses a piston in a housing with air escaping through a calibrated orifice to control the rate of shock extension. No oil or valving, just air being pushed out (and back in on shock retraction) through a small hole. Very simple but works surprisingly well.

[BC12D-4-85]

If not STC'd how available have any Field Approvals been?

Gary

[Crash, Jr.]

If not STC'd how available have any Field Approvals been?

Gary

They are STC'd so no field approval needed

[Doug Budd]

There is better choices than the coil over shocks but I like the set up


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[RVBottomly]

It's not actually an air spring doing the supporting. It works pretty much like a Piper bungee/hydrasorb unit except instead of using an oil shock it uses a piston in a housing with air escaping through a calibrated orifice to control the rate of shock extension. No oil or valving, just air being pushed out (and back in on shock retraction) through a small hole. Very simple but works surprisingly well.

Now I have another winter project!

I've got the tubes and bungees. Time for an experiment on air damping. I gave up on the oil damping idea and only briefly considered air damping—which is odd because every time I let go of my storm door I admire the hissing of the door return.

[Franky]

There you go.

Can you imagine for one minute if you had a Scout wing on it (36 ft)?

Franky

[Franky]

Hi Crash

As i said before, the deal is so good on the Citabria that there is no way that i could built a cub for the price that it will cost me to built myself a highly modified bird, remember, as homebuilder, it only cost the price of the materiels, nothing for certified manpower and there such a nice choice of avionic stuffs today for the homebuilt
market, it must make certified aircrafts owners jealous.

[BC12D-4-85]

I can get a N-Number for a 7GCBC that has the Scout wing extensions. Then order records from the FAA that should include the Form 337 related to that mod. Might help.

Gary

[Franky]

The aircraft i'm buying have the wood spars, i need to rebuilt the wings, i'll do it in the experimental or amateur category if you prefer, it is easier to do in Canada than the US, so it is going to be a 36 + ft wingspan from either d&e or from Nick Smith in Ontario, Ca.

Franky

[BC12D-4-85]

If extending the wings consider duplicating the Scout's vertical stabilizer. It varies from the 7GCBC by having the leading edge extended full height. The rudder has reduced chord at the top to compensate. Add VG's to the wings and tail for better control.

Gary

[Franky]

Thank's Gary

Yep, that's all part of the plan + a suspension type landing gears, floats and maybe an O-360.

Franky