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Cummins spinner fit issue

Bavafa

Well Known Member
I was wondering if anyone else has had any issues fitting a Commins spinner. With the front plate installed, my spinner does not go far back enough for the aft edge of it to be flushed with the aft edge of the back plate by around 0.062”. Now best I can tell the aft edge of the front plate is preventing from going farther back. This is with a Harzell CS prop in a RV14

I was wondering if anyone else has had this issue and if so how did they fix it.
 
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My Cummin spinner went on just like yours. I accepted that it was the best it would do.

The back plate still clears the front of the cowling by about 3/16".

I guess it's not perfect, but so are lots of other things.
 
This is mine installed a few years ago. Hope this helps. It too was little short but
works well
otQ.jpg
 
Thank you guys, looks like at least two people with the same issue.
It does not look to be a safety issue with edge distance, only cosmetic I guess.
 
I did a trial fit of the spinner tonight, both front and back plates installed. As was previously posted, it was perhaps 1/16? short of being flush with the backplate.

The first photo shows the Hartzell diagram on using spacers and washers. I started out with the spacer and one washer between the spinner backplate and the prop hub - this yielded the previously reported 1/16? short problem. I then used just the spacer and the spinner is now flush with the backplate.

Do this fit up before you follow the Cummin video on drilling holes and such for spinner screws.

Carl

15_CE17_A0-9_ED6-4_DA8-_BCBD-6_BCA12_CB2_E32.jpg

2_B15_EF1_B-_D126-4_F06-_A372-8_F55_C22_E6032.jpg
 
I did a trial fit of the spinner tonight, both front and back plates installed. As was previously posted, it was perhaps 1/16? short of being flush with the backplate.

The first photo shows the Hartzell diagram on using spacers and washers. I started out with the spacer and one washer between the spinner backplate and the prop hub - this yielded the previously reported 1/16? short problem. I then used just the spacer and the spinner is now flush with the backplate.

Do this fit up before you follow the Cummin video on drilling holes and such for spinner screws.

Carl

15_CE17_A0-9_ED6-4_DA8-_BCBD-6_BCA12_CB2_E32.jpg

2_B15_EF1_B-_D126-4_F06-_A372-8_F55_C22_E6032.jpg
Carl,
Thanks for reporting. I have also removed the extra washer and that improved it but there is still the 1/6+ discrepancy for mine.
 
That washer is there for clearance between the blade and bulkhead when blade is at full travel. DO NOT recommend removing the washer.
 
That washer is there for clearance between the blade and bulkhead when blade is at full travel. DO NOT recommend removing the washer.

I thought of this, but at first blush clearance looked ok. I?ll do a full blade travel clearance check later today and report back.

Carl
 
That washer is there for clearance between the blade and bulkhead when blade is at full travel. DO NOT recommend removing the washer.
Can you please be more specific about the bulkhead. I did a full blade movement and did not notice any interference.
 
I sent a note to Allan at Cummins Spinners on the issue. He tells me he is looking at the issue and will offer a fix to those that purchased the spinner.

Carl
 
Thanks Carl, Allan told me the same. I hope it is in time for my first flight.

I had to test again for clearance without the washer. Thru the full range, I get 0.090 clearance with the outer edge of the back plate. The additional washer would be nice but it looks like it will be OK. I did not have this washer on my IO-360 which uses the same back plate and did not have any issues.

P.S. I am building a 14 and there might be some difference between a 14 and a 10 in this regard. My plans does not talk about the three washers but it does show one on the back and one on the front of the plate.
 
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Can you please be more specific about the bulkhead. I did a full blade movement and did not notice any interference.

In 1994/95 I was fitting the spinner on our 6 and as I recall the plans did not call for a washer, just the spacer. The timing was perfect as Vans came out with an update to add the washer due to interference of the blade touching the rear bulkhead so I did. In checking the clearance afterward it was about the same as the washer thickness IIRC. Things may have changed since then but would certainly recommend taking the blades stop to stop and make sure of proper clearance.
 
I did another fit up of the spinner with both front and rear plates using just the spacer between the backplate and the hub. Results:
- There is 1/8? or so clearance between the backplate and the prop blade when moving the blade through full travel.
- The spinner is still 1/16? or so short of being flush with back edge of the back plate (see photo).

At this point I?m stopped on fitting the cowl. The fix is for the spinner to be 1/8? or so longer.

I?ll send a note with photos to Allan at Cummins Spinners.

Carl
2_B44_C3_AA-_BAFC-478_A-8947-_F45_D679_B8366.jpg
 
Hmmm. I'll have to check mine again. I got it just over a year ago and have been doing other cowl stuff...... Thanks for this thread.
 
Carl, Please keep us posted. Just took delivery of a Cummins spinner for the -10. Haven't begun fitting it.
 
Hartzell Spinner Kit

Hi all

It has only just come to my attention there is a problem with the fitting of the Hartzell C/S spinner kit. The front plates have been made to large.

I am currently working on a fix to get a new smaller front plate made.

If you have not fitted your spinner yet, DO NOT drill anything until I send you a new front plate.

Please email me if you require a new replacement front plate.
The replacement will be free

Please note it will be 3-4 weeks before I have the new plates ready to send
 
I check mine and it fits with no gap. My prop came with .25" nylon spacers on the backplate bolts and those are in place.....not sure how youd get the backplate to rest flat otherwise.

Just for giggles, I put a washer between the front plate and the prop hub, and the spinner spaced out exactly the washer width on the back plate - and no (minor) persuading would close that gap.

FWIW, My ship date from AU was basically a year ago today.....
 
I check mine and it fits with no gap. My prop came with .25" nylon spacers on the backplate bolts and those are in place.....not sure how youd get the backplate to rest flat otherwise.

Just for giggles, I put a washer between the front plate and the prop hub, and the spinner spaced out exactly the washer width on the back plate - and no (minor) persuading would close that gap.

FWIW, My ship date from AU was basically a year ago today.....

Mani,
Not sure which plane you are making but in a 14, there is no washer between the front plate and the hub but there is a washer added to the spacers that is provided by Harzell. check your plans and also make sure you have clearance at full rotation.
 
Mani,
Not sure which plane you are making but in a 14, there is no washer between the front plate and the hub but there is a washer added to the spacers that is provided by Harzell. check your plans and also make sure you have clearance at full rotation.

Haha on me! Unlike you guys that have exceptionally complete documentation, not so with my mfg. I stopped being able to use "my plans" about 3yrs ago - theyre only for the basic airframe and wings/metal skinned parts, nothing else.

But thanks for the clarification.

So, how thick is this washer and why do you guys need it? This doesnt seem a model specific thing, though it might be a prop hub issue.....I'm using a short Bhub (see sig block).
 
Haha on me! Unlike you guys that have exceptionally complete documentation, not so with my mfg. I stopped being able to use "my plans" about 3yrs ago - theyre only for the basic airframe and wings/metal skinned parts, nothing else.

But thanks for the clarification.

So, how thick is this washer and why do you guys need it? This doesnt seem a model specific thing, though it might be a prop hub issue.....I'm using a short Bhub (see sig block).
The washer is a standard size washer and gives the blades enough clearance to clear the back plate. So turn your blade from stop to stop and observe to see how much clearance you have from the backplate
 
The washer is a standard size washer and gives the blades enough clearance to clear the back plate. So turn your blade from stop to stop and observe to see how much clearance you have from the backplate

Thanks a bunch for pushing me on this. Pic atched

BL: My blades hit, and push the backplate forward (up in the pic) at full stroke. 2x .062" washers(.125 total) on the bushing give me .035" clearance between blades and backplate....

Sending email to Allan.
2wrhmqp.jpg
 
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Thanks a bunch for pushing me on this. Pic atched

BL: My blades hit, and push the backplate forward (up in the pic) at full stroke. 2x .062" washers(.125 total) on the bushing give me .035" clearance between blades and backplate....

Sending email to Allan.
2wrhmqp.jpg
No problem and it is good that you checked. This obviously impacts your spinner fit which will end up with the same issue as some of us are having.

Hopefully Allan's solution come in time before my first flight.
 
Another uh oh - for me anyway

I dunno if this is an issue for you guys since you have VAF guidance on the additional washers between the backplate and prop, but after having added those and now clearing the backplate, I find my spinner cutouts are not deep enough - the prop touches the spinner there at full course deflection. It doesnt actually push the spinner out of place, but theres zero clearance now. Might be something to check on yours....I sent a note to Allan.

Also FWIW, I'd long ago finished mounting my cowl and of course, did it with no backplate washers (dont know what you dont know), so now I have a spot where the cowl touches the back plate as well. I have some ways out of that pickle tho, so that should be easier to fix. Not Allan's fault; just due to my ignorance......
 
I dunno if this is an issue for you guys since you have VAF guidance on the additional washers between the backplate and prop, but after having added those and now clearing the backplate, I find my spinner cutouts are not deep enough - the prop touches the spinner there at full course deflection. It doesnt actually push the spinner out of place, but theres zero clearance now. Might be something to check on yours....I sent a note to Allan.

Also FWIW, I'd long ago finished mounting my cowl and of course, did it with no backplate washers (dont know what you dont know), so now I have a spot where the cowl touches the back plate as well. I have some ways out of that pickle tho, so that should be easier to fix. Not Allan's fault; just due to my ignorance......
Its all part of building and learning. The good news is that you found it and it can be fixed before flying and possibly getting into a deeper issue.
 
What prop?

What hub and blades are you guys using with this spinner? My spinner wont fit with my F7666 Arrow paddle blades........Allan says the spinner is only made for the blended F7479 blades.....
 
I have been trying to get hold of Allan by email to no avail. Can someone please help me with his telephone numbers. It is nowhere on his website, invoice, etc. Thank you.
 
Where is Allan?

Two emails sent to Allan asking when the replacement front plate will be sent. No response.

Anyone get an update from him?

Carl
 
Two emails sent to Allan asking when the replacement front plate will be sent. No response.

Anyone get an update from him?

Carl

Nope. Ive got crickets to my last email asking to verify I was still on the list for the new front plate vs sending my spinner back. That was 2 weeks ago.....
 
I also got a note from him today with the same info. He stated that he only reads his emails once week. :confused:
 
Anybody got any emails from Allan about whether hes indeed started shipping new front bulkheads yet?

Shot him a note, but well......
 
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I ordered a RV-14 spinner from Allan a month ago.......no reply.
Emailed him again 2 weeks ago to confirm my order........no reply.
 
Another month has gone by, and I've got nothing from Allan, email or packages. Any one get any new front bulkheads yet?
 
Likewise, no response to any email. Waiting is getting frustrating, it'd not even abysmal communication, its none.
 
Well here we are 2019 and nothing from Allan. I guess we now have to consider this company defunct.....
 
Possible fix?

So I too got tired of waiting and very disappointed with Allan?s failure to honor his promise.

I asked my machinest RV buddy to make a press so that the front spinner can get just enough bend aft to gain the 1/16? or so needed for the spinner to move aft and be flush with the aft spinner plate. He made a 2.5? center press, surrounded by a steel ring that will sandwich the plate on the hydraulic press so the plate edges stay in the same plane.

Some final tests and we?ll give this a try next week. I?ll let you know how it goes. If this works, easy enough to do anyone else?s front plate that needs it.

Carl
 
So I too got tired of waiting and very disappointed with Allan?s failure to honor his promise.

I asked my machinest RV buddy to make a press so that the front spinner can get just enough bend aft to gain the 1/16? or so needed for the spinner to move aft and be flush with the aft spinner plate. He made a 2.5? center press, surrounded by a steel ring that will sandwich the plate on the hydraulic press so the plate edges stay in the same plane.

Some final tests and we?ll give this a try next week. I?ll let you know how it goes. If this works, easy enough to do anyone else?s front plate that needs it.

Carl

I'm interested. If it works out ok, I'll drive down to see you....
 
Mani,

The mod to the front plate got deferred (stuff happens) but it is next on the list of things to do. Give me a couple of weeks and I?ll post results.

Carl
 
Spinner fixed!

Photos attached on how I fixed the spinner. Here is the problem - spinner does not slide aft far enough to be flush with the spinner backplate.
20190308-143108.jpg


My machinist buddy fabricated a die to dimple the Cummins provided forward spinner plate so that the outside edge moves slightly aft. The die has rounded edges and goes into a piece of hardwood so that we impart no sharp edges. Not shown is the steel ring clamped around the die to prevent the plate from deforming:
20190308-152242.jpg

20190308-153136.jpg


Here is the final result:
20190308-163813.jpg


We did cycle the prop from full fine pitch to full course pitch to verify clearance.

Now that this is done I can get back to finishing up.
Carl
 
Response!

Alan appears to be back. Just got this in response to my ping on the front plate:

Thanks for the update.
Please confirm your postal address and I will send in the next few days
cheers
Allan

___________

We shall see.
 
Just curious if anyone has received anything from Allan, he responded back that he is shipping again but have not got anything in the mail so far.
 
Contact With Cummins Spinner

I received an email from Allan on March 21 saying that he had a constant speed spinner ready to ship that I had previously ordered on March 7. I sent payment on March 24 and received the spinner on April 5th.

It was packed well and arrived in excellent condition. A quick test fit showed that the provided forward bulkhead was a perfect fit with none of the rear bulkhead alignment issues that others have experienced.

Allan says he is back on the job and that seems to be the case.
 
It seems then that he is shipping new spinners, but not the parts to replace the faulty ones? Apologies if I am wrong, but I did not hear from him yet. :mad:
 
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