In the meantime here's an add to this thread. The Air Research Flight/Operating Manual Supplement for the C-170 and others:

PDF link

The USA FAA approved version may differ when finalized.

Gary

I have heard from a close friend who is on the WIng-X mailing list that they actually, finally got FAA approval for the 170A/B STC.

It adds 50 lbs to max gross. increasing it to 2250. So, maybe a nice STOL addition but not the useful load increase like the 180 version.

The Canadian STC allows for a gross weight of 2400 if equipped with an 0-360 @ 180 hp or greater, Yaaaaaaaaa.

Mapleflt wrote:The Canadian STC allows for a gross weight of 2400 if equipped with an 0-360 @ 180 hp or greater, Yaaaaaaaaa.

Yes, the C-170 with a big engine really can use a 2400 pound gross weight. Hopefully, they'll apply that to US approvals as well.

MTV

2250 is the max take of weight with Wing-X for the 170.
50 lb. increase was all they could do even if you have 180 HP or higher.

akgreg wrote:2250 is the max take of weight with Wing-X for the 170.
50 lb. increase was all they could do even if you have 180 HP or higher.

Not sure why its different; the two civil authorities usually follow suit with each other but not this time, its 2400 with 180 hp or greater in Canada.

akgreg wrote:2250 is the max take of weight with Wing-X for the 170.
50 lb. increase was all they could do even if you have 180 HP or higher.

Wow! That’s really unfortunate. Considering how long those folks have been working to get this done in the US, though…….

Sounds like another case of “Not invented here” by FAA.

MTV

Something isn't ringing true for me, the attached document in the OP is dated 2001, we need to see the FAA document. In my experience the two civil agencies usually "accept" each others STC approvals with the occasional minor caveats. The acceptation to this are FAA 337's or Canadian LSTC's. Transport Canada (TC) only recognizes fully approved FAA STC's and similarly I don't believe the FAA recognizes TC LSTC's.

There is no 200 lb. GTOW increase in Canada for the 170.

This is directly from Paul at Wing-X:

“The Canadian and FAA STC read exactly the same and there is no difference in GTOW increases in Canada vs. USA
for any model with any engine”

Hope this clears up any confusion

Very unfortunate; makes it a somewhat useless STC, adding weight for a minimal gain.

Mapleflt wrote:Something isn't ringing true for me, the attached document in the OP is dated 2001, we need to see the FAA document. In my experience the two civil agencies usually "accept" each others STC approvals with the occasional minor caveats. The acceptation to this are FAA 337's or Canadian LSTC's. Transport Canada (TC) only recognizes fully approved FAA STC's and similarly I don't believe the FAA recognizes TC LSTC's.

Close, but depending on the inspector during imports, some 337s are allowed in. Fortunately there is still some people at TC that can take a common sense approach.

Mapleflt wrote:Very unfortunate; makes it a somewhat useless STC, adding weight for a minimal gain.

Isn't it like 4 feet extra wingspan? Doesn't that provide a lower speed takeoff/landing?

Zzz wrote:

Mapleflt wrote:Very unfortunate; makes it a somewhat useless STC, adding weight for a minimal gain.

Isn't it like 4 feet extra wingspan? Doesn't that provide a lower speed takeoff/landing?

3 feet of additional wingspan. This will create extra lift. Yes, better takeoff and landing performance.

And, more lift in cruise will mean a slightly lower wing incidence and potentially faster speed.

Furthermore, the extra gross weight will cover the additional weight of the kit. And using the rough guide of $1000 per pound of weight removed, the difference between the weight of the kit and the additional gross weight will pay for a lot of the kit.....at least that's what you tell the wife.

Until we see the approval document all is conjecture. I'm curious how the reference to "180 or greater" in the posted document might play into the final approval. If and its a big IF but should the final document "require "180 or better" as part of the approved STC that will make this the most expense wing extension in the World.

There's no question that the wing extensions improve takeoff performance, especially on floats. That benefit probably would be minimal with a stock engine in a 170, though.

MTV

mtv wrote:There's no question that the wing extensions improve takeoff performance, especially on floats. That benefit probably would be minimal with a stock engine in a 170, though.

MTV

Exactly so for this to be a "financial" success for the developer the final "approved" STC be it FAA or TC could very well spell out the requirement for "180 or greater".

Mapleflt wrote:Exactly so for this to be a "financial" success for the developer the final "approved" STC be it FAA or TC could very well spell out the requirement for "180 or greater".

Maple Syrup,

I have the final approved paperwork. I have the kit. There is no “180 or greater” language used. I’m pretty sure the quote I posted from Paul at Wing-X was very clear about what you get. 50 lbs.

akgreg wrote:

Mapleflt wrote:Exactly so for this to be a "financial" success for the developer the final "approved" STC be it FAA or TC could very well spell out the requirement for "180 or greater".

Maple Syrup,

I have the final approved paperwork. I have the kit. There is no “180 or greater” language used. I’m pretty sure the quote I posted from Paul at Wing-X was very clear about what you get. 50 lbs.

Any reason why you are choosing to be derogatory with my BCP handle !!

It seemed nicer than calling you thick headed.

With that this thread has taken an unfortunate turn, so at the risk of offending anyone else I’m done.