[Fly4Funn]

Anybody out there running the stock Vans spinner with no screws installed in the front bulkhead? I would love to not have them installed if I knew it was OK. The local A&P has looked at the fit and tells me I should be OK if I don't install any. Another builder of a plastic airplane agrees with him and says it would not cause any issues with no bolts in the front. Both agreed that I should line the bulkhead with tape, put a coat of proseal on it and mount the spinner and let it cure so that the bulkhead would fit perfectly to the spinner. It is a very snug fit as it is but I had planned to do the proseal thing anyway. Just looking for what some others have done. Don't want that departing the airplane while in flight!!

 

[Ron Lee]

If you have a FP prop I don't see how it will work. You have to torque the prop bolts and the front bulkhead is under the bolts..and crush plate I think. You must have a CS prop.

 

[Lycosaurus]

Custom spinner flange.

I have a fp prop, and made a screwless spinner (check the archives). Basically, I added fiberglass to create a flange on the spinner. Installed nutlates on this flange, which allows you to screw the rear bulkhead to the spinner via this flange (the cowl must be removed in order to do this). The forward bulkhead contacts the spinner, via some hardened proseal on the spinner.

My flange is quite thick, since some others had issues with parts of it breaking off. So far so good, after 27 hours.

 

[Captain Avgas]

Screwless spinner

Anybody out there running the stock Vans spinner with no screws installed in the front bulkhead?

I have a CS prop and I modified a stock Vans spinner to produce a "screwless" finish on both the front and rear spinner bulkheads. I used a process developed by Brian Holman who has a multi award winning RV6 with a screwless spinner. He has many hundreds of hours with this spinner design and it is performing flawlessly to date.

Many spinners on turbine props have no front bulkhead screws. They often have a rubber rim on the front bulkhead and the spinner sits on that without any other mechanical restraint. Knowing that I figured it was a feasible solution.

I fabricated a rear fibreglass rim inside the spinner that bolts to the rear bulkhead from the rear (platenuts installed on the fibreglass rim). You can see what I did in the following photo. The photo also shows that I also built up the inside of the spinner at the front bulkhead position to ensure a perfect fit right across the bearing surface (most important).

The trick to this is to fabricate the rear rim so that the distance between the rim and the front bulkhead "sealing" position is reduced by 1/16". Thus when the rear rim is bolted up it pushes the front bulkhead into the "sealing" position with a positive prestress. I hope this makes sense to you (a bit hard to describe).

In reality a lot of standard RV spinners do not fit well at the front bulkhead and even although they are screwed at that location they often break the screws due to oscillating stresses. Screws at the rear bulkhead also often fracture for the same reason.

Having said that I have no personal experience with this mod other than Brian Holman's experience as I am not yet flying.

I can tell you however that it looks just great with no visible screws whatsoever. On the down side it took me a lot of time to fabricate and I would not recommend it to anyone who was not prepared to think it right through and then devote serious time and effort to do it properly. I plan to make a thorough spinner inspection part of my annual.....but then everyone should do that.

 

[Rick6a]

Rod,

You don't say what prop you are running. Using Van's standard fiberglass spinner with a constant speed prop, I decided to compromise on the issue and install 3 of the six forward spinner screws. I have closely monitored the spinner while another person has run the engine up and have noticed the spinner seems to rotate perfectly true with no imbalance noted. My feeling is if however, a screw later fractures or departs the spinner, I will then add screws at the other three nutplate locations which have already been piloted through the spinner using a tiny but hardly noticeable #60 drill bit.

 

[jrvssgl]

I mounted spinner number one with screws and used silicone to 'bed' the spinner on the front bulkhead. Be careful. When I went to take it off to prime it, I had to chop my spinner off as it glued on so bloody hard nothing was taking it off. If you are to proseal it on without using some kind of a releasing agent of some sort you will never get that spinner off again. My second 160 dollar spinner should be here shortly!! I really should put on a picture of the destruction it took to take it off.

My second attempt will be screws only on the rear bulkhead. And am going to try and get the front spinner bulkhead real tight to the spinner to prevent any possible movement, with no screws there.

Also throw the stainless steel screws vans supplies with the spinner away, and use countersunk structural screws with tinnerman washers. Way stronger!

 

[dhall_polo]

WWF moves on spinner

If you are to proseal it on without using some kind of a releasing agent of some sort you will never get that spinner off again. My second 160 dollar spinner should be here shortly!! I really should put on a picture of the destruction it took to take it off.

I had that scare. I did the proseal thing. I waxed the spinner bulkhead thoroughly, then put proseal on and screwed the spinner into place. I waited a day or two for the proseal to cure, and went to pull the spinner off. All I can say is that I feel pretty good about what a great product proseal is given what I did to make it not work. Thankfully, I broke out some grand master wwf champion wrestling moves and forced the spinner into submission. Who's your daddy!?!

I still chickened out on the screwless thing. Got every screw van's specified, even with my nice snug prosealed fit.

 

[Fly4Funn]

You have all given me lots to think about. I am running a CS Hartzell prop (sorry about leaving that out) and have thought a lot about the screwless spinner which is why I seem to think that even with the screws in the back as designed, the front would be OK since the screwless spinner doesn't have them. My spinner fits very well at the front bulkhead and seems to run within .020 of perfectly true. The edge distance on the rear is close because the spinner just barely does make it to the back edge of the rear plate. I may still do the screwless installation. The lower cowl was so screwed up that I ended up cutting the junk snorkle off with a jigsaw and starting over. All of the products I have received from Vans were great but I personally would have never let something as poorly done and awful looking as the cowl I received leave my place of business! After all the work that took, I'm not sure I want to tackle the building of the screwless spinner!!

 

[Champ]

I was planning on not using screws on my front spinner bulkhead - RV-8, IO375, dual P-Mags, Hartzell Blended Airfoil F7497-2, pan head screws on rear bulkhead without washers, proseal sandwich on front bulkhead (black shadow in picture) courtesy of Dan Horton posts.

How have you without front bulkhead screws made out???

 

[RV7A Flyer]

Screwless spinner here, no problems after 280+ hours. I did the thing where I put a little ProSeal on the forward bulkhead, wrapped cellophane around it and then installed the spinner and let it set up, to make a "formed in place" gasket, but honestly, I don't think I'd do it again, as there's almost no ProSeal on the thing after trimming edges and such. AND, after the first 25 hours of flight or so, it was an almighty booger to get the spinner off (since then, I coated inside and the bulkhead flange with mold release wax, liberally, and haven't had any issues).

YMMV...do a search for "screwless spinner" for tips.

 

[MikeyDale]

I built the screwless spinner. I painted the inside of the spinner with PVA (several coats) around the area the forward bulkhead contacted the spinner. I put a heavy bead of proseal on the bulkhead and mounted the spinner. After a few days I attempted to pull it off and it was very tight and I got a little worried when it wouldnt come loose. I found that light tapping on the spinner in the area of the proseal caused it to separate little by little. I finally came loose.

 

[Champ]

Although I am satisfied with how my spinner tracks and have a good "prosealed" fit to the front bulkhead, I just wondered who might of had any long term problems without screws to the front bulkhead. Like broken rear bulkhead screws, spinner cracks at the rear bulkhead.

I did use packing tape, wax & PVA on the inside of the spinner & didn't have any trouble getting the spinner off initially.

 

[Neal@F14]

Instead of ProSeal, I ran a bead of Permatex Ultra Gray silicone gasket maker (cures harder than regular silicone, made especially to stick to aluminum engine parts in high vibration environments) around the lip of my spinner front bulkhead, then placed a strip of Saran Wrap around the wet silicone to keep it from sticking to the inside of the spinner, and installed the spinner and let it cure overnight.
Next day, removed the spinner, trimmed off all the excess cured silicone from around the bulkhead with a razor blade, and wiped an extremely thin fresh layer of silicone around the perimeter to fill up the tiny space the Saran Wrap layer would've taken up, and then let that dry overnight too. Now the front bulkhead has a nice, snug, rubber-cushioned fit against the inside of the composite spinner dome. I've even balanced the front bulkhead using a mower blade balancer and used a small bead of the same silicone as my balance weight inside the outer lip of the aluminum bulkhead.

 

[deek]

Instead of ProSeal, I ran a bead of Permatex Ultra Gray silicone gasket maker (cures harder than regular silicone, made especially to stick to aluminum engine parts in high vibration environments) around the lip of my spinner front bulkhead, then placed a strip of Saran Wrap around the wet silicone to keep it from sticking to the inside of the spinner, and installed the spinner and let it cure overnight.
Next day, removed the spinner, trimmed off all the excess cured silicone from around the bulkhead with a razor blade, and wiped an extremely thin fresh layer of silicone around the perimeter to fill up the tiny space the Saran Wrap layer would've taken up, and then let that dry overnight too. Now the front bulkhead has a nice, snug, rubber-cushioned fit against the inside of the composite spinner dome. I've even balanced the front bulkhead using a mower blade balancer and used a small bead of the same silicone as my balance weight inside the outer lip of the aluminum bulkhead.

^^^ This is exactly what the many in the EZ crowd has on their "aft" spinner bulkheads. Mine has over 3,000 hours of troublefree service.

 

[Champ]

^^^ This is exactly what the many in the EZ crowd has on their "aft" spinner bulkheads. Mine has over 3,000 hours of troublefree service.

Is cured Permatex Ultra Gray silicone gasket maker similar to cured proseal? I'm looking for the same trouble free service on my prosealed front bulkhead.

 

[deek]

Is cured Permatex Ultra Gray silicone gasket maker similar to cured proseal? I'm looking for the same trouble free service on my prosealed front bulkhead.

Someone else will have to answer this; 5 homebuilts but all epoxy/glass and have never used Proseal (yet)

 

[Neal@F14]

Is cured Permatex Ultra Gray silicone gasket maker similar to cured proseal? I'm looking for the same trouble free service on my prosealed front bulkhead.

Very similar in both color and hardness. I think it cures a bit more rigid than Proseal... recently cured ProSeal is still a bit soft. The hardness of Ultra Gray reminds me of Proseal that's been cured for about 10 years

 

[vasrv7a]

If anyone's interested, I have for sale a serviceable fiberglass spinner dome with rear bulkhead that had been used with a Sensenich fixed pitch propeller (72FM8S9-1-85). The spinner is painted white and was fitted and installed, without front bulkhead screws... Both the spinner and bulkhead had been in service on an RV-7A with an O-360 since 2006. I also have the 2 1/4 inch spacer (SPM8S9) which is in good condition...

If interested, please contact me... [email protected]

Victor