11AC Spinner and Nose Bowl Ring

[joea]

I have been away from the shop for a few days, the R&D group has moved me into other positions. I had three schedule changes in two weeks, little tiring.

Charles

Keep plugging away at things and eventually hope it slows down a bit.

[lewislech]

Each day I look at your work and dream about getting a spinner and backplate for my 11AC yellowbird. Please let me know what the status is on getting one made.
THanks,
Lewis

[seaheli]

I have not forgot about the Chief spinners, the R&D shop has kept me busy!

I am working on two solutions for issues with the spinner bulkhead. Bill Pancake and I have discussed an option that requires measurements for each propeller installation. "I need hub thickness for each propeller that is commonly used on Chiefs."

Could someone help me compile a list of propellers and hub thickness?


Charles

[Chief Pilot]

Hi Charles, great to hear from you again -- terrific work you're doing with the spinners and bulkheads. With regard to prop hub thickness, the Sensenich Type Certificate Data sheets give nominal hub dimensions for those props. TCD 1P2 for metal 74CK and 76AK series. TCD P-170 for wood props. The Sensenich web site has this document Metal Propeller Hub Thicknesses under "documents" / "specifications". That one lists thickness to .001". I have attached a table (I think) with some of the common propellers used. (You'll want to have some others verify this info.) Hope this helps.

Raleigh

[joea]

Charles,

Great to see you back on the board and glad you are staying busy.

Your name came up a lot at Middletown last weekend and every comment was great, so you have a lot of fans.

Hope that you have time to do some Aeronca work in the future!

Joe A

PS saw a Sedan with one of your Chief style spinners on it and it looked great!

[seaheli]

In researching and working on a solution for the spinner bulkheads I feel that a steel bulkhead would be the optimal way to proceed!

I researched several options and a "heat treated thicker (.080") bulkhead" or "steel bulkhead" was the best avenue. The added cost for heat treat was $225.00 per unit.

Any thoughts or comments from the Aeronca community???

Charles

[joea]

Great to see you back and personally I could care less what its made out of. The steel might be a few ounces heavier but thats what one of my soda's weights...

Might try to do a couple of "beta copies" and pass them around for some testing and see how the guys out in the field like them.

Joe A

[Carl Prather]

Yes, Charles, I have questions:

Where do I send my money? Do you use Paypal?

I'm glad to see you back on the spinner. Your work looked exemplary.

Tx,

Carl Prather
Gilroy, CA

[Richard Murray]

Simply fascinating reading. As a newbie to this forum, I worked backwards through all eight pages of this thread and applaud Charles for continuing a lost art.

[Chief Pilot]

How about a front bulkhead for additional support? If it were made and fitted with same precision as your rear bulkhead it may absorb or prevent some of the vibration that's cracking the rear bulkhead. It might not even need attachment screws through the spinner - maybe just a snug fit inside the dome, but held in place with the prop through-bolts.

[Chief Pilot]

In researching and working on a solution for the spinner bulkheads I feel that a steel bulkhead would be the optimal way to proceed! I researched several options and a "heat treated thicker (.080") bulkhead" or "steel bulkhead" was the best avenue. The added cost for heat treat was $225.00 per unit. Any thoughts or comments from the Aeronca community???

Here's a photo of a spinner and steel backing plate. I was told it's from an Aeronca Chief, but it doesn't match any Aeronca drawings I have. Does anyone know what airplane it may be from? The dome is a perfect fit with a Bob Carr Aeronca Chief backing plate.

[seaheli]

Check dwg # 3-637. That bulkhead resembles this drawing. What is the dia. and flange height of your bulkhead?

[joea]

Simply fascinating reading. As a newbie to this forum, I worked backwards through all eight pages of this thread and applaud Charles for continuing a lost art.

It really is a work of art. I briefly considered doing this long before Charles took it over and simply did not have the time, workspace nor expertise that I felt it would take. After seeing what Charles is doing am glad I did not try it as he is a thousand times better person for the job!

[Chief Pilot]

Check dwg # 3-637. That bulkhead resembles this drawing. What is the dia. and flange height of your bulkhead?

Good catch. The bulkhead does look somewhat like 3-637 except it's designed so the spinner fits on the opposite side. The flange is bent somewhat more than 90 degrees and the "open" side goes inside the dome toward the nose. The flange has relief cutouts for the prop. You can see one of them at the 2:00 o'clock position. Not a very good design, in my opinion -- difficult to manufacture and subject to cracking at the relief cutouts. Both sides are cracked, although they don't show in the photo. The major diameter is about 10.8" and the flange is .75". It's made from steel, about 24 gauge. Also notice the holes in the spinner dome for a front bulkhead. In a side-by-side comparison I can't see any difference in the size and shape between this one and one for a Chief. So the mystery remains.

thanks

[seaheli]

The spinner tooling was returned to Mr. Carr.

I want the Chief spinners to move forward. My schedule did not allow much time in the workshop.

Charles