Aeronca Chum Aircraft

[EDGEFLY]

Richard,

I just printed the document in the link with Google Chrome. I guess it just didn't like the Apple ios. Many Thanks.
Now, if we could only get copies of those 5 subassembly drwgs.........

CAVU

Dale

[Richard Murray]

Dale,

Glad to hear you finally got access to the file.

Thanks for bringing up the subject. It was interesting to learn that Aeronca had developed this under license from ERCO.

I found this on Wikipedia,
"Aeronca obtained a licence to produce the Ercoupe 415 as the Aeronca 12AC Chum in 1946 and built two prototypes: NX39637, with the Ercoupe twin-tail, and NX83772 with a larger, single tail, metal wings and trailing-link struts in the main undercarriage. The Chum was powered by a Continental C-85J with a 108 mph (174 km/h) cruise speed.[12] No production ensued.[13][14][15]"

The complexity of the mechanics to coordinate the rudder with the ailerons that Fred Weick advanced in 1934 is amazing.

Richard

[joea]

I believe that one was purchased or donated to Goodyear and the other to the University of Ohio. Both of the planes have disappeared without a trace. Trust me, the NAA has spent a lot of time trying to find them...

[skyking3286]

I know that Aeronca had a drawing of the twin tail Chum, but I can't remember (at least this morning) seeing a photo of it in that configuration. I do have a photo
of the small tailed prototype. Ah, one of those questions that we should have asked twenty years ago when the old Aeronca employees were still active. Did the twin tailed ever fly or was it put into single tail before the flight test. I suppose if anyone has the Aeronca employee newsletter form that era, it would have the best
chance of having a photo of a first flight.

And thanks for the article. Learned a little more about how they were going to market the Chum and some more details. Sad to realize that it was so close to
being "real"...if they had produced it in 1945, who knows....

[EDGEFLY]

joea,

Did the NAA ever come up with a paper trail ? By that I mean drwgs, BOM's, etc ? I saw on the Internet that the twin tail version was destroyed during flight testing and its' remains were salvaged for material value. that isn't vetted, could have been someone's guess.

Dale

[joea]

Dale,

We found people who remembered the airplanes and believe that Craig MacVeigh found the data-tag and some paperwork on Ebay or Barnstormers. It was purchased and donated to the NAA the last I heard.

We do have some blueprints for the 12AC, but not much... Brian Matz or Craig would know more than I do...

Joe

[Richard Murray]

For CHUM lovers everywhere I believe the first model 12A-1 was a twin tail NX39367 and it went to Goodyear



This canceled registration and this note from Wikipedia are what I base that belief on.



Richard

[skyking3286]

On the fAA email board, we have been discussing the Chum and this new photo that appeared on eBay... first photo I've seen of the Chum as it ended it's career.

http://www.ebay.com/itm/1948-Press-Phot ... 0888865742

Scroll to the bottom of the ended listing and you'll see the photo and the date on the back of the photo.

[Richard Murray]

Mark thanks for starting that discussion. I have been following those posts and captured some screenshots of the listing and photo from eBay.









The confusing part is the picture which is clearly from Goodyear shows the conventional tail. This would invalidate the Wikipedia data.

[skyking3286]

That's why I asked about photos of the twin tail prototype.

My sense of it is that when they received the license from Ercoupe, they first thought about doing it as per the license. They had some early 1945 artwork showing a twin tail Chum. By the time they started to actually cut metal, the design had a single rather small tail. It would appear that the single tail had less area than the twin tails it replaced. So the first modification was to increase rudder/vert stab volume. By the time Aeronca finished the plane development, almost all the Ercoupe ideas were absent. No diagonal truss in the wings, just straight ribs. Landing gear was redesigned. No twin tail. It may have started with the Ercoupe, but by the time they
finished it up for production, there wasn't much in common, just a low wing, low horsepowered airplane.

We have photos of an original twin tail Piper Apache, before Stinson/Piper made the switch to a single tail. But I don't believe anyone has a photo of a twin tailed Chum in the flesh or in the air. Just an artist's impression of the first ideas of the design. The art work was done at the same time they were working on the 11 series and that artwork is pretty general and misses a few details of the production design, as it did with the 7AC. So we have a design that was worked on as they were also working on the 7/11 series and as busy as they were pushing the 7/11 out the door, the 12AC didn't get much attention toward production until it was too late. The board went with the 15AC and stopped the 12AC series.

The best bet for getting a twin tail Aeronca Chum photo would be to see if the old Aeronca employee newsletter has a photo, circa 1945 or so. Those old employee newsletters were a wonderful resource for history. Many of the photos we are using now were first used in the newsletter.

[skyking3286]

[skyking3286]

Above, from Popular Science May, 1945. This is the first try of production that showed up in Flying magazine a few months later.

[skyking3286]

January 1947 issue of Popular Science

[Jerry Eichenberger]

As someone said, we have had a lot of discussion of the Chum on the fAA email list in the past few days.
I note from the pictures here that the Chum didn't have a trailing link landing gear like the Ercoupe does. I can't imagine how it would have much cross wind component since it had to be landed in a crab, and that's possibly why Goodyear was investigating its castering cross wind gear system. Perhaps we've stumbled upon why the airplane never was produced - maybe it just didn't work.
Also, I can't understand why both Ercoupe and Aeronca would think that each company could make and sell what is, in essence, the same airplane. Maybe in those heady, post WW II boom days, Ercoupe just figured that they could not keep up with demand, and decided to let another major manufacturer produce a like airplane too and collect a royalty on the license. Who knows.

[Paul Agaliotis]

I think the licence would be for the style of control system used, not to build the Ercoupe. Weick's design and systems were being tried by a lot of people to make the "sipn proof aircraft".
Landing is like any other tri-gear airplane. Even if landed crooked it tends to straighten out. Flown both with and without rudder control, also not much difference. You can keep a wing low on landing if you want to. The rudders only move outboard and a very small amount.
Paul