EAA Biplane and Aerobatics

[Cliff Killeen]

Wanting information on EAA biplane. It doesn't seem to be considered aerobatic, why. Has anyone tried replacing the wings with something else, perhaps acro duster wings

[cwilliamrose]

Why do you assume the wings are the weak point -- if there is a weak point?

[rwanttaja]

What would you require for proof that a modified EAA biplane is indeed strong enough for aerobatics? I suspect there isn't any documentation of the loading of the stock wings.

Ron Wanttaja

[Airmutt]

Why not just build an Acro Sport??

[martymayes]

It’s about as aerobatic as any other 100-125 hp biplane

[WLIU]

If you have a set of Starduster wings why would you put anything but a Starduster fuselage between them?

Best of luck

Wes

[Cliff Killeen]

Why do you assume the wings are the weak point -- if there is a weak point?
Not necessarily thT they are weak, but going on the duster performance figures, they are a really good performer, both in speed and aeros.

[Cliff Killeen]

What would you require for proof that a modified EAA biplane is indeed strong enough for aerobatics? I suspect there isn't any documentation of the loading of the stock wings.

Ron Wanttaja
Confirmation that someone had proven them beyond rolls and loops. On the paperwork I have, they are rated to + and - 9, but my plane wears a placard that prohibits aerobatic maneouvers.

[Cliff Killeen]

Why not just build an Acro Sport??
I have built an RV6A, and love it, but my aerobatic attempts are reaching the safe limits of the RV. I don't have enough time left to build another plane, but perhaps a set of wings would be possible

[Cliff Killeen]

It’s about as aerobatic as any other 100-125 hp biplane
Thanks, I suspect that you are right, but I'm looking for something more. An Acroduster appeals to me, but very hard to find

[Cliff Killeen]

If you have a set of Starduster wings why would you put anything but a Starduster fuselage between them?

Best of luck

Wes
I have the biplane, I don't consider the fuselage to be the defining point for aeros, still looking for information and opinions re changing wings. I still have time to do that if it is a possibility

[cwilliamrose]

So you're fine with having the fuselage fail. Or the tail failing. You just don't want the wings to fail?? Personally I don't want any failures and that means all the parts have to work together and have matched capabilities. I predict that if you cobble together a Frankenstein biplane you will not be happy with either the effort required or the results.

[Airmutt]

Well said.

[martymayes]

I've seen EAA Biplanes flown in Basic and Sportsman events, even beating out the big $$$ monoplanes flying in the same events.

[martymayes]

Thanks, I suspect that you are right, but I'm looking for something more. An Acroduster appeals to me, but very hard to find

I agree, a single seat Acroduster with an aluminum fuselage is kindaof a neat bird but there are not many that come up for sale.

[Airmutt]

Wouldn’t that be more of a function of pilot skill vs type aircraft??? I thought basic and sportsman class was setup to level the playing field

[rwanttaja]

I have the biplane, I don't consider the fuselage to be the defining point for aeros, still looking for information and opinions re changing wings. I still have time to do that if it is a possibility

Unless you know the failure mode of the EAA biplane, you don't know if just replacing the wings will provide an advantage. Maybe it's not the wings that fail first...maybe it's the cabane struts, the interplane struts, the flying-wire attachment points, lower wing attachment points on the fuselage, etc. Or even the engine mount, horizontal stabilizer bracing, etc.

You said earlier that the EAA Biplane is "rated for +/-9 G"... is there any sort of supporting documentation? Test data? Years ago, a friend took over marketing of a fairly common homebuilt aircraft. He found the previous marketing chief had claimed the design was aerobatic and had published all sorts of graphs...but there was NO data to back it up. My friend suspects the previous guy made it all up to sell more airplanes.

A better question might by *why* your airplane is placarded against aerobatics if it supposedly was "rated" for 9Gs. At one point in the past, the FAA did seem to be just including "no aerobatics" as a blanket prohibition, unless the builder asked for it not to be included.

Finally, doesn't hurt to ask, but the EAA Biplane fleet is so small (71 aircraft) that you're unlikely to find one with a specific hybrid modification. AND to ask for proof of a specific degree of stress testing.....

Ron Wanttaja

[Joda]

A better question might by *why* your airplane is placarded against aerobatics if it supposedly was "rated" for 9Gs. At one point in the past, the FAA did seem to be just including "no aerobatics" as a blanket prohibition, unless the builder asked for it not to be included.

I've actually come across Pitts Specials that had operating limitations that prohibited Aerobatics!! Definitely not because the airplane isn't rated for same!! Usually, this happened because neither the applicant nor the FAA inspector really read the operating limitations, or understood the aircraft in question.

A placard prohibiting aerobatics may have been simply added by a previous owner on a whim! There is certainly no structural reason that I'm aware of in an EAA biplane that would preclude aerobatic maneuvers.

[martymayes]

The EAA biplane evolved from the Gere Sport and I think four aeronautical engineers were involved in updating the design and drawing plans. Bud Gere was 19 yrs old when he designed the Gere Sport so I'd wager the engineers were "thorough" in the redesign process. Have there ever been any structural related failures?

[WLIU]

My understanding is that to have operating limitations that "approve" aerobatics you must fly and log aerobatic figures flown during Phase I flight testing. Which is to say that you fly loops, slow rolls, snap rolls, and spins. That pretty much covers everything and you are good to go. Builders who are not interested or do not have the competency likely wind up with the limitation. But you can have your operating limitations updated to remove the restriction if you are willing to demonstrate the capability.

Best of luck,

Wes

[Cliff Killeen]

So you're fine with having the fuselage fail. Or the tail failing. You just don't want the wings to fail?? Personally I don't want any failures and that means all the parts have to work together and have matched capabilities. I predict that if you cobble together a Frankenstein biplane you will not be happy with either the effort required or the results.
Points taken and understood.I appreciate your input

[Cliff Killeen]

Unless you know the failure mode of the EAA biplane, you don't know if just replacing the wings will provide an advantage. Maybe it's not the wings that fail first...maybe it's the cabane struts, the interplane struts, the flying-wire attachment points, lower wing attachment points on the fuselage, etc. Or even the engine mount, horizontal stabilizer bracing, etc.

You said earlier that the EAA Biplane is "rated for +/-9 G"... is there any sort of supporting documentation? Test data? Years ago, a friend took over marketing of a fairly common homebuilt aircraft. He found the previous marketing chief had claimed the design was aerobatic and had published all sorts of graphs...but there was NO data to back it up. My friend suspects the previous guy made it all up to sell more airplanes.

A better question might by *why* your airplane is placarded against aerobatics if it supposedly was "rated" for 9Gs. At one point in the past, the FAA did seem to be just including "no aerobatics" as a blanket prohibition, unless the builder asked for it not to be included.

Finally, doesn't hurt to ask, but the EAA Biplane fleet is so small (71 aircraft) that you're unlikely to find one with a specific hybrid modification. AND to ask for proof of a specific degree of stress testing.....

Ron Wanttaja
Certainly nothing positive so far, I'll wait a while longer for a Duster.

[Joda]

My understanding is that to have operating limitations that "approve" aerobatics you must fly and log aerobatic figures flown during Phase I flight testing.

Actually, you have it backwards. You must first have operating limitations that allow aerobatics, then you test and log specific maneuvers during flight testing. If your operating limitations prohibit aerobatics, you can't even legally test the maneuvers in the first place.

So, the proper procedure is to request that the operating limitations allow aerobatics if the aircraft is capable. Then, once the limitations are issues, a competent pilot may test and log various maneuvers during the phase one flight test period (or an additional flight test period at a later date). Even if the operating limitations allow aerobatics, only those maneuvers that are performed and logged during a flight test period are allowed to be performed during phase 2 operations.

I always encourage my applicants to request the aerobatic operating limitations if the aircraft is capable, even i they themselves never plan to do aerobatics. A subsequent owner can place the aircraft back into phase 1 and test maneuvers at a later time. If the operating limitations prohibit aerobatics, a subsequent owner would have to go back to the FAA and have new limitations issued in order to perform aerobatics in the aircraft. Easier to have it done right away rather than have to redo the limitations later.