spades

[Big Ed]

Marion Cole held the STC for spades on wood wing 7/8 series. Have not been able to find a current vendor, so I assume they are no longer in production. Maybe could find a used pair on salvage from someone switching to metal wings? Unsure of legal implications of such an installation.

My old wood winged 76 Decathlon CS had spades on it when I got it in 2003. I will say that when we got rid of it a few years later, there was enough play in the aileron hinge mounts to concern me.

ACA has made it clear they are not interested in facilitating use or longevity of wood wings in any way.

 

[Bartman]

@aftCG Since you are the resident spades guru, would you happen to know if the spades are supposed to be parallel to a line that spans the camber of the wing's underside or are they supposed to be parallel to the flat bottom of the wing at the trailing edge? The directions say they should be parallel to the bottom of the wing but they don't specify what exactly the bottom of the wing is. There is camber, it isn't perfectly flat so the directions are ambiguous.

Thanks!
Bart

 

[Big Ed]

I would guess parallel to chord line, either of the wing or the aileron itself.

 

[Bartman]

the confusing part is that the Olin Pash STC instructions say to make the spade parallel to the bottom of the wing but the bottom is undercambered so there's an imaginary chord line (LE to TE), there is the arched underside of the wing, and then there is the nearly flat last couple of feet into the trailing edge. Mine are set parallel to an imaginary flat line that bridges the underside of the wing camber. Not sure if that's right though.

 

[aftCG]

Huh. I never slapped a straight edge on the bottom of my Citabria wing but I would have bet a cheap dinner it was flat.

Can't help you Decathlon guys but if it were me I would do as Bart suggests and use a 6' straight edge to bridge any undercamber, clamp the ailerons flat to that and make the spade parallel to all that.

 

[LTLucas]

Hey Bartman or anyone else who may have an answer, would you happen to have a copy of the full Olin Pash STC to include installation instructions and other verbiage?

 

[BB57]

Huh. I never slapped a straight edge on the bottom of my Citabria wing but I would have bet a cheap dinner it was flat.

Can't help you Decathlon guys but if it were me I would do as Bart suggests and use a 6' straight edge to bridge any undercamber, clamp the ailerons flat to that and make the spade parallel to all that.

The Aeronca 65 series, the 7 series Champs and Citabrias and the 8GCBC Scout use the NACA 4412 airfoil. It has a slight under camber from the 20% to 100% position. Now that you know it’s there you’ll see it if you look for it.



The Aeronca C1-3, 11 series Chiefs and the Aeronca K series all use the Clark Y. It’s basically flat from the 20% to 100% position.



The Aeronca LA,LB, and LC use the semi symmetrical NACA 2218. It is however a pretty fat airfoil by more modern semi symmetrical standards.



The 8KCAB Decathlon uses the semi symmetrical NACA 1412.



For comparison purposes the J-3, J-5, PA-11, PA-12, 14, 15, 16, 17 18, 20, 22, 23 and 25 all use a modified USA-35B airfoil (it’s reported to be slightly thinner than the regular USA-35B). The difference between the Clark Y and the USA-35B is the slight under camber on the USA-35B. And here all y’all thought the cub had a flat wing too.

 

[Bartman]

Huh. I never slapped a straight edge on the bottom of my Citabria wing but I would have bet a cheap dinner it was flat.

Can't help you Decathlon guys but if it were me I would do as Bart suggests and use a 6' straight edge to bridge any undercamber, clamp the ailerons flat to that and make the spade parallel to all that.

i only noticed it when the wing went onto a flat workbench for the spars conversion and it didn't sit flat on the table. "well, I'll be damned" or something like that went through my head.

 

[Bartman]

The Aeronca 65 series, the 7 series Champs and Citabrias and the 8GCBC Scout use the NACA 4412 airfoil.....................

Thanks for putting all of that together!

 

[Chri5]

Not relevant to the above discussion, but I have some questions about spades.

I have just bought a 64' 7ECA and want to add spades. It was fully rebuilt in 09' with full metal wings that were extended by one rib. The ailerons seem to have mounting points on the outside edge and enough clearance to fit something in there, although I know the previous owner never flew with spades. I did a bit of training in 2015 model that had them before I flew mine, and I really liked the feel. I'm in Canada and the rebuilt wings mean it is now technically a "homebuilt" (approximate to US experimental category), so I don't need to worry about an STC. Are there any schematics floating around the web I can use to make my own? They don't look overly complex to make. Other than taking a bit of weight off the ailerons, is there any other performance changes or limitations I should be aware of?

 

[Johan Whiteman]

I made a post under New Guy regarding spades.

 

[Johan Whiteman]

This is what I have on my 1970 woodspar 7GCBC

 

[Hiperbiper]

Just wondering; has anyone contacted Olin Pash's family to see about selling/transferring the STC?
If they didn't want to deal with it at all maybe they could be persuaded to cancel/recind the STC.
Once the STC is dead a set of reverse engineered spades might be possible...
Better still would be obtaining the STC for use by the current and future owners.

I might give Larry Cole shout and see what the status of the Cole brothers STC is currently...

Chris

 

[LTLucas]

I believe aftCG had tried to do exactly what you stated in the past. He’s done a lot of leg work in the direction of reverse engineering the spades. So much so, I have had a set created for my 7KCAB. In the process of getting a field approval from our local DAR. Olin doesn’t really seem interested. But I’m all about being a squeaky wheel to get things moving in the right direction for the group.

 

[aftCG]

The problem is that we live in a different world than we used to. Things like Olin's spades and even Rainbow Ron's upgraded spruce spars would be much harder to certify now. Reverse engineering the spades was the easy part. But to get an STC approval you'd have to do exhaustive analysis and flight testing to prove they're safe - you know, the real engineering.
My information was only second hand and I never spoke with Olin directly, but he was not even interested in supporting people trying to move a set of previously installed planes to a new airplane because of the hassle. Even if you could talk him out of the rights to the STC he would probably still be named in the lawsuit over the first smoking hole in the ground. I can't say I blame him for washing his hands of it all.

 

[Big Ed]

Olin Pash has been dead for 9 years.

 

[aftCG]

Olin Pash has been dead for 9 years.

I did mean to say "his family". I've been dabbling in this issue for over 15 years and wasn't sure exactly when he left the pattern.

 

[Bartman]

i would guess it isn't the FAA's job to police intellectual property rights so if someone wanted to make an application for an STC that was visually similar to another existing but dormant STC, they'd probably go along with the process. The question I'd be curious to ask is whether or not they'd let you use an existing STC's good track record as a basis for at least part of the approval.

 

[Big Ed]

I did mean to say "his family". I've been dabbling in this issue for over 15 years and wasn't sure exactly when he left the pattern.

It does raise an interesting question: does an STC remain the property of a person's estate? Does it pass down in perpetuity, or is there some kind of expiration as with patent law? What about "orphan" STC's owned by now-defunct business entities?

 

[aftCG]

i would guess it isn't the FAA's job to police intellectual property rights so if someone wanted to make an application for an STC that was visually similar to another existing but dormant STC, they'd probably go along with the process. The question I'd be curious to ask is whether or not they'd let you use an existing STC's good track record as a basis for at least part of the approval.

Well an example of different STCs which were essentially identical would be engine upgrades. I know that my old plane N602Z was used to create two different "single use" engine STCs. It was a 7ECA which left the factory with an O-200. Same cowl, engine mount and (problematic) exhaust system as the Lycoming O-235, but slap on an O-320. Not real hard and no new parts.
[red herring discussion removed]
A long winded way of saying that I agree the FAA isn't in the business of protecting intellectual property.

It does raise an interesting question: does an STC remain the property of a person's estate? Does it pass down in perpetuity, or is there some kind of expiration as with patent law? What about "orphan" STC's owned by now-defunct business entities?

From what I've seen they certainly can transfer to the estate. There are plenty of those for the Citabria. When I wanted to install the Desser Aero Classic 8.50s I found two STCs for 8.50 tires. One was owned by the family of the man who developed it and it says right on it that it can be used without compensation (so I did). The specs for the tire matched the Desser perfectly. The other was really only good for a set of Goodyear 8.50s and was currently owned by (IIRC) AWB who didn't reply to my inquiry.

Some people get old and sell the rights. Some people get old and don't. If you could talk Olin's family out of the rights for free you wouldn't exactly be ordering a Lamborghini next week. I think it is about a half dozen people a year inquire about getting spades for a wood wing airplane.