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  #1  
Old 11-16-2017, 03:15 PM
jeffw@sc47's Avatar
jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
Default Cummins 13" Hartzell spinner

Been prepping the 13" Cummins aluminum spinner for a few days now. <cumminspinners.com>

The spinner and kit are a work of art and very solid, his front plate is a little thicker than the one supplied by Van's for their spinner. The instructions on-line are very good with the exception of one adjustment I'll point out.

In his video he says to lay out six equal spaces on each half side of the spinner for the backplate screws and between each screw location the measurement should be around 3-33/64". But, when the distance between the first and last of the 7 holes (to the backplate screws adjacent to each prop cutout) is divided into 6 equal spaces (7 screw holes, he provided 14 nut plates for the backplate mounting holes), the holes are about 2-21/32" apart. Minor hiccup, but cause for a bit of head scratching. I went with 7 screws each side, 6 equal spaces.

I pilot drilled all of the front and backplate holes in the spinner following the instructions on the video - that worked fine. I did create the layout sheet he describes in his video on a CAD file which may be a little more precise, and plotted it full size.

I mounted the backplate to the prop hub and the front plate to the front of the prop hub, and then the whole prop assembly back on the engine and temporarily cleco clamped the spinner to the to the backplate. I removed a spark plug from each cylinder so I could turn the prop and not have the engine jiggling around so that I could track the spinner nose to get it aligned. Don't want to have a wobbling spinner. The spinner point was not tracking on-center by about 3/32".

Was very careful to make sure that anything that shouldn't be moving to cause this was as stable as possible. Had a friend slowly turn the prop so I could look at the spinner close-up in relation to a stationary pointer on a solid bench. Spent most of morning playing with it. I took the spinner frontplate off and found that the center hole and the four front plate attach holes (1/4") were off-center along one of the axes by about 1/16" to 0.10", translating to the approx 3/32" wobble at the nose of the spinner.

dims shown are distance from outer backplate circumference to outside edge of the 1/4" mounting holes, one is 2.88", the other 2.95" +/-


Sent Alan an email (in Austrailia so not very accessible via phone) requesting that he send me a replacement frontplate, pre-drilled or not drilled. So now waiting for reply or a replacement spinner frontplate.
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Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47

Last edited by jeffw@sc47 : 11-16-2017 at 03:18 PM.
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  #2  
Old 11-16-2017, 04:01 PM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 2,127
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Jeff,
Please keep us updated with this installation, I am really interested in this upgrade and would like to follow as I am get to this point.
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RV7A - IO360M1B - SOLD
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  #3  
Old 11-21-2017, 11:08 AM
jeffw@sc47's Avatar
jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
Default How to best fix the off-center spinner front plate?

I requested a replacement for Cummin's 13" spinner front plate a week ago and sent two additional emails to Alan (cspinners@gmail.com) asking if he will send the replacement. No replies to any of my requests that a replacement would be coming. I also offered to purchase a replacement because without it the spinner isn't worth much.

It appears that I may end up with an expensive spun aluminum lamp shade. Nice spinner but Z-grade for the front plate and follow-up support.

Maybe on vacation or ill, not know.

I need a Plan-B - I came up with one that I think might work.

I will drill out the four 1/4" mounting holes in the off-center front plate to 3/8". This would allow the spinner front plate to adjust the approximate 1/16" to 0.10" to meet center on the propeller hub. I would fabricate a front plate centering/reinforcing plate around 4" diameter with 4- 1/4" on-center mounting holes pre-drilled in it that would match to the four holes in the front plate, plus 16 - #40 pilot holes equally spaced in a circular pattern that would eventually be match drilled through the Cummin front plate for riveting the two together (using 470-4 rivets), keeping the rivets outside the circumference of the flat portion of the front hub.

I believe that I could mount the front plate and the fabricated plate on the hub with the 1/4" bolts snug - but loose enough to adjust the spinner to get its nose centered without any wobble. Then carefully match-drill the front plate mounting holes using the pilot holes drilled in the spinner.

I believe that this could fix the front plate. Once it is centered and there is no wobble in the spinner I don't think there is going to be any stresses on the spinner front plate, with the centering/reinforcing plate that would cause concern.

Does this sound like a good way to recover?
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Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47

Last edited by jeffw@sc47 : 11-21-2017 at 12:31 PM.
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  #4  
Old 11-21-2017, 11:54 AM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 2,127
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This seems like a good plan B and ought to work but it is a shame that there has not been any response or support. I was about to order one but will wait at least some what longer to see if there is a logical explanation for the lack of support.

Thanks for the follow up and please let us know how things works out.
Best wishes and luck.
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RV7A - IO360M1B - SOLD
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  #5  
Old 11-21-2017, 02:11 PM
Larco Larco is offline
 
Join Date: Mar 2005
Location: DVT Phoenix
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I have one of Alans spinners and so far very happy. Wouldn't be if your shoes. I suggest thinking about rotating the bulkhead 45 degrees and drilling new holes between the existing ones??
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  #6  
Old 11-21-2017, 02:54 PM
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maniago maniago is offline
 
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Location: Bowie MD
Posts: 371
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Quote:
Originally Posted by Larco View Post
I have one of Alans spinners and so far very happy. Wouldn't be if your shoes. I suggest thinking about rotating the bulkhead 45 degrees and drilling new holes between the existing ones??
I have one of Allans spinners too, and just ordered a bigger triangle to do what he shows on the video.

But I'm with Larco above. Rotate and drill new holes. Plenty of edge spacing, and if you dork up the 45deg, you still can do it at 22.5 with plenty of hole spacing. It doesnt take any torque load, just holds the nose in place.

That said, appreciate you posting here, cause I'm going to mount my front bulkhead again and rotate the prop with a dial indicator on the flange and see if it runs true before I start the drilling process.....
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Bushby Mustang II (building); IO-360B1E, C2YR-BF/F7666-2, Superior cold sump, James cowl
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Last edited by maniago : 11-21-2017 at 02:56 PM.
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  #7  
Old 11-21-2017, 03:54 PM
eddieseve eddieseve is offline
 
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 582
Default

Hey Jeff

As far as I know Allan does not make the back or front plates, they are ordered from VAN's as part of either the fixed pitch or constant speed prop kits.

Cheers

Quote:
Originally Posted by jeffw@sc47 View Post
Been prepping the 13" Cummins aluminum spinner for a few days now. <cumminspinners.com>

The spinner and kit are a work of art and very solid, his front plate is a little thicker than the one supplied by Van's for their spinner. The instructions on-line are very good with the exception of one adjustment I'll point out.

In his video he says to lay out six equal spaces on each half side of the spinner for the backplate screws and between each screw location the measurement should be around 3-33/64". But, when the distance between the first and last of the 7 holes (to the backplate screws adjacent to each prop cutout) is divided into 6 equal spaces (7 screw holes, he provided 14 nut plates for the backplate mounting holes), the holes are about 2-21/32" apart. Minor hiccup, but cause for a bit of head scratching. I went with 7 screws each side, 6 equal spaces.

I pilot drilled all of the front and backplate holes in the spinner following the instructions on the video - that worked fine. I did create the layout sheet he describes in his video on a CAD file which may be a little more precise, and plotted it full size.

I mounted the backplate to the prop hub and the front plate to the front of the prop hub, and then the whole prop assembly back on the engine and temporarily cleco clamped the spinner to the to the backplate. I removed a spark plug from each cylinder so I could turn the prop and not have the engine jiggling around so that I could track the spinner nose to get it aligned. Don't want to have a wobbling spinner. The spinner point was not tracking on-center by about 3/32".

Was very careful to make sure that anything that shouldn't be moving to cause this was as stable as possible. Had a friend slowly turn the prop so I could look at the spinner close-up in relation to a stationary pointer on a solid bench. Spent most of morning playing with it. I took the spinner frontplate off and found that the center hole and the four front plate attach holes (1/4") were off-center along one of the axes by about 1/16" to 0.10", translating to the approx 3/32" wobble at the nose of the spinner.

dims shown are distance from outer backplate circumference to outside edge of the 1/4" mounting holes, one is 2.88", the other 2.95" +/-


Sent Alan an email (in Austrailia so not very accessible via phone) requesting that he send me a replacement frontplate, pre-drilled or not drilled. So now waiting for reply or a replacement spinner frontplate.
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  #8  
Old 11-21-2017, 06:18 PM
jeffw@sc47's Avatar
jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
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Quote:
Originally Posted by eddieseve View Post
Hey Jeff

As far as I know Allan does not make the back or front plates, they are ordered from VAN's as part of either the fixed pitch or constant speed prop kits.

Cheers
Not true for Cummin's Hartzell C/S 13" spinner. Alan sends the front plate for this spinner. The Vans' back plate does work for the C/s spinner. It is very slightly smaller in diameter than the Vans' spinner front plate for their spinner. Don't know if Alan makes the front plate, I am assuming that he does. If he would send me a replacement with only the center hole drilled and not the four mounting holes, I can get those drilled perfectly on-center.
__________________
Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47
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  #9  
Old 11-21-2017, 08:36 PM
Steve b Steve b is offline
 
Join Date: Jul 2015
Location: Camdenton, mo.
Posts: 3
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I recently purchased a spinner from Alan. The order was delayed because he found the forward bulkhead to be cracked and had to wait for a replacement from his supplier.Rear bulkhead is Van's.
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  #10  
Old 11-22-2017, 07:18 AM
jeffw@sc47's Avatar
jeffw@sc47 jeffw@sc47 is offline
 
Join Date: Aug 2014
Location: Simpsonville, SC (SC47)
Posts: 163
Default Front plate pressed - not spun!

That makes sense now. I looked again at the front plate and it does not look like it was spun, it was likely pressed. If the front plate is coming from a supplier, then they are not going through any kind of quality inspection there or at Cummin.

It didn't compute that the center and four mounting holes could be off-center if the plate was spun because the center hole would have likely been drilled first and then the plate spun; but if pressed then the holes being off-center could easily happen.

All five of the holes in my front plate were off center, including the 3/4" dia. center hole that has the prop hub valve and washer to pass through. I wasn't so concerned with the center hole being off-center. I reamed and deburred the four 1/4" mounting holes as they were not very 'clean'.

Steve_b > Sounds like Alan looked at your front plate before he sent it and saw an obvious crack, off-center holes not so easy to see.

I still have not gotten any reply from Alan. Grade-Z.

I'll send off another inquiry before I start with adapting my off-center plate and see if Cummin Spinners will make good their product.
__________________
Jeff Warren
Simpsonville, SC (SC47)
1946 Bellanca Cruisair 14-13-2 (71 YRS OLD 8/15/17)
RV14A (N14ZT), Ser#140195
Start 10/11/14
IO-390 Lyc Tbolt / CS Hartzell
Dues paid 12/1/17 (USArmy 2/67-2/70)
www.mykitlog.com/jeffw@sc47
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