Aermotor lower furl ring question

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bobceng
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Joined: Tue Aug 25, 2020 6:28 pm
Location: Northport, Michigan

Aermotor lower furl ring question

Post by bobceng »

I am repairing a worn Aermotor A602 lower furl ring and have two Q's:
1) I replaced the (2) ring-to-strap pins (that were badly worn) with new bolts and lock nuts, and added metal/re-drilled the "wallowed" strap holes. Should the bolts be tightened to prevent ANY strap movement at the ring, or be just loose enough to permit some swing as the furl mechanism operates?
2) The straps were separated from the cast ring when I got the mill. The straps have a slight bevel on one edge, and the pins are slightly off-center in the cast ring channels; should the bevel-edge be on the narrow side?
It looks like IF the straps should swing a bit, that the bevel would allow it, but limit how much swing. If anyone "happens" to have a lower furl ring and could post a photo of the point where the straps are attached, it would be most helpful. Thanks!
billcobb
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Re: Aermotor lower furl ring question

Post by billcobb »

Aermotor.png
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windybob
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Re: Aermotor lower furl ring question

Post by windybob »

I think those types of connections should be a little on the loose side rather than on the tight side. Let me see about a picture this morning.
Call Dan Benjamin for parts. P M me for the phone number.
Mister Ed
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Re: Aermotor lower furl ring question

Post by Mister Ed »

Here you go Bob & Bob ... Edit - (wait a minute ... now I am second guessing myself if I have that bend going the correct way).
IMG_20200829_105427982.jpg
And if you make it down this way ...
IMG_20200829_105506215 (1).jpg
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Last edited by Mister Ed on Sat Aug 29, 2020 10:13 am, edited 1 time in total.
Thanks,
Ed
Mister Ed
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Re: Aermotor lower furl ring question

Post by Mister Ed »

Oh, those rivets are originally a shoulder rivets to allow the pivot points to move freely (like Windy mentions). One time I did turn some on the lathe, but its been a while. LoTec (I think) at one point had a neat writeup on how he fixes these, but for the life of me I cannot recall his procedure. That write up might have been lost to the crash of the old forum.
Thanks,
Ed
bobceng
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Re: Aermotor lower furl ring question

Post by bobceng »

Yup...that's the shot I needed to see! Thank you, thank you!
It does look like the bevel edge of the strap is on the narrow side of the channel. The more I thought about it, keeping the strap stationary would have required a narrower channel casting, and maybe two rivets. I'm going to mount the straps per your top picture, and back the lock nut off just enough to let the straps swing without jumping the channel "ribs".

I used two 1 1/2" long hex bolts that were the same diameter as the pin holes (1/4"); I placed washers under the hex head, then used two lock nuts that allow for adjusting how tight the strap is held to the hub casting. Lock nuts allow the bolt to spin with no danger of backing off.

I like the look of a carriage bolt head, but from 30 feet up.....

Again, thanks so much!
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windybob
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Re: Aermotor lower furl ring question

Post by windybob »

Yeah, see i went and forgot the picture. Today was hectic, but forgot anyway.

I use bolts with self locking nuts. I think I run the bolts from the inside out. Been a while since I fixed some.
Call Dan Benjamin for parts. P M me for the phone number.
bobceng
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Joined: Tue Aug 25, 2020 6:28 pm
Location: Northport, Michigan

Re: Aermotor lower furl ring question

Post by bobceng »

billcobb kindly posted a line drawing of the lower furl ring mechanism (see a couple of postings above). This evening, I looked at the Lindsay Baker 702 book I bought last week (the best thing I did next to joining this forum!) and Fig. 15 on page 9 shows the same line drawing, except it shows the short angle iron pieces secured to the mast base. It is evident from this drawing that as the ring rises, the furl lever will scribe an arc that MUST swing the two straps outward a bit to prevent damaging them or shearing the shoulder pins or base attachment. So, the straps cannot be bolted tight and must be able to swing.

Any thoughts?
Mister Ed
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Re: Aermotor lower furl ring question

Post by Mister Ed »

They need to be able to move, that's why the shoulder rivets were originally used.
Thanks,
Ed
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