Official FMS 1500mm P-47D Razorback Thread

[davegee]

Hi Steve: I've got the printer warming up now! I'll let you know how it goes. I think Rex is still planning to make me a machined aluminum hub for my plane, so I could send this one to him if he wants it and isn't going to machine his own CE dome. Is always good to have a spare on hand just in case....

Thanks so much!

Davegee

Hi Steve: print went very well. I'll pick up a tap for it tomorrow at Ace. I like your profile of this bullet shaped prop dome, better than what we came up with over 2 years ago. After I sand and prep it, I'll probably use some Alclad alumiinum paints to paint it. Should be able to test it in the next week or so with my Ol' Cock P-47D that had the CE prop on it. Will keep U advised!

Thanks again!

Cheers

Davegee

[davegee]

P-47 Curtis Prop Hub_v2.stl

Dave,

Give this a go.

I will print one later today or overnight.

I enlarged the base opening where the thrust washer and nut are to 0.906"

The thread is M10 150 and I would run a tap through it by hand after printing.

The only place it should require 'support material' in the hollowed opening for the thrust washer and nut.

Extra detail could be added at the base to simulate the flat metal flange, the locking nuts with wire and holes for alignment, but I digress .

Let me know how it goes...

Best, LB

Hi Steve: I've got the printer warming up now! I'll let you know how it goes. I think Rex is still planning to make me a machined aluminum hub for my plane, so I could send this one to him if he wants it and isn't going to machine his own CE dome. Is always good to have a spare on hand just in case....

Thanks so much!

Davegee

[Elbee]

Hi Elbee: if you still need the specs on the thrust washer and nut:

the thrust washer is 0.8655 inches in diameter

the prop nut maximum diameter measured from point to point across the nut as it spins, is .7335 inches, so it looks like it would barely clear a .75 inch diameter hole, in theory, anyway.

cheers

dg

P-47 Curtis Prop Hub_v2.stl

Dave,

Give this a go.

I will print one later today or overnight.

I enlarged the base opening where the thrust washer and nut are to 0.906"

The thread is M10 150 and I would run a tap through it by hand after printing.

The only place it should require 'support material' in the hollowed opening for the thrust washer and nut.

Extra detail could be added at the base to simulate the flat metal flange, the locking nuts with wire and holes for alignment, but I digress .

Let me know how it goes...

Best, LB

[davegee]

davegee

In your first picture of the thrust washer, nut, and shaft, what is the diameter of that thrust washer?

Will 3/4" hole be large enough?

Best, LB

Hi Elbee: if you still need the specs on the thrust washer and nut:

the thrust washer is 0.8655 inches in diameter

the prop nut maximum diameter measured from point to point across the nut as it spins, is .7335 inches, so it looks like it would barely clear a .75 inch diameter hole, in theory, anyway.

cheers

dg

[Grossman56]

Right on Durango!
Was hoping my new NX8 would be waiting for me when I got home, but it was delayed
Now they're saying Monday, what can you do??
As my old DX8 Gen1 finally gave up the ghost (registered her on Dec31, 2014)
No radio, lots of yardwork.

Grossman56
(Dangerous Dan)

[jetfool]

Thanks Dan. Modelers helping modelers, best hobby to be in.

[Grossman56]

Here's a great video showing a lot of close ups of the RB P47

https://www.youtube.com/watch?v=VxWKOHPPNlM

And here's a still of the spinner used with the Curtis electric props

Hopefully this helps!

Grossman56
(Dangerous Dan)

[jetfool]

Gentleman, My old eyes are deceiving me. Just measured the bore and washer. The washer is 7/8" (.875) diameter and I used a 29/32 (.906) drill bit to bore the hole. Forgive me!
Best Regards, Rex

[jetfool]

Davegee and Elbee,
On my alum. spinner I found 3/4" bore and 3/8" depth works great and clears the prop nut and washer ok. The prop washer was in mm and smaller than my 3/4" bore, spinner fits tight against prop hub with hand tight, takes a little muscle to untighten. 1/2" depth would be ok also.
Dave I'm still working the vs2 alum. spinner. It will weigh more than a 3d one, but I still think the weight will not be a problem flying with it. I will keep all informed. The alum looks good on the model polished up.
Best Regards, Rex

[Elbee]

davegee

In your first picture of the thrust washer, nut, and shaft, what is the diameter of that thrust washer?

Will 3/4" hole be large enough?

Best, LB

[davegee]

DG,

So, if I increase the "gap" at the base to 0.5" from 0.375" and decrease the threaded portion to 0.5" from 1.0" it's a go?

And you think the profile is good to go as well?

Best, LB

Hi LB and Rex: I am enclosing a few pics I took of my setup for a CE (Curtiss Electric) prop set up and printed propeller dome done a couple of years ago. I have been using this with this airplane with no problems at all since then. There are certainly ways to improve it, but it worked for this project for the time being.

You can see that I have mounted the FMS V3 Corsair prop and hub and replaced the FMS OEM prop shaft with the larger one that the 1700mm Corsair uses for the V3 setup. Works great.

My printed spinner or CE prop dome I just measured the inside with a caliper. From the aft edge of the prop dome to where the threaded hole for the prop shaft to screw into is 1/2" (.5") deep. We continued that hole much longer than it needed to be, drilling and tapping it to 1 (one) inch deep. With this arrangement, the prop dome inside clears over the nut that fastens down the CE prop and hub to the prop shaft and airplane.

There's probably a lot of ways you could go with this, but that's what we did two years ago. Other things came up after that and we didn't go any further until Rex and I came up with the idea to have some HS students use this as a project to learn more about 3D printing and other topics for their school.

I think your profile shape for the prop dome looks very good. Mine has a definite point where it changes from a cylinder to a curved dome at the end. I didn't like how that looked and we were going to try and improve that, but never did.

I think to your question, you could try it reducing the "gap" from .5 inches to .375 inches deep, but without test fitting one with that reduced dimension, I couldn't guarantee that the inside of the CE dome wouldn't catch on something when you tried to screw (hand torque) it on over the propeller shaft and the nut. For ours, .5 inches worked fine, and we made a carved out dome area inside just to be sure. It was never a problem doing it like this. Same for the depth of the threaded hole to screw on the CE prop dome onto the prop shaft. I'm pretty sure if you only drilled and tapped to .5 inches instead of the 1 (one) inch that we did, it would work fine. Even though weight really wasn't a problem for this printed CE dome, I think we wanted to test for any problems if we eventually made an aluminum spinner, which was one of the goals at that time, to reduce weight as much as possible.

Would be good to get Rex' opinion and take on these things before going any further.

Best,

DG

[Elbee]

Hi Elbee: I think I can chime in a bit and Rex can add anything he wants to, since I have been using these for several years. The M10 nut screws tight with a wrench onto the threaded prop motor shaft. That's what keeps the propeller and its hub attached to the airplane.The simulated Curtiss Electric prop dome is recessed about 1/2" or so to clear the nut affixed on the prop shaft. The Curtiss prop dome is also threaded to hand-tighten onto the threaded prop shaft but really doesn't have any structural strength (at least as a printed part to keeping the propeller in place on the shaft in flight.)

Working with my contact on the East coast a few years ago, we never really came up with a satisfactory profile design as good as you have come up with to mimic the Curtis Electric prop dome. I still fly my printed dome on one of my P-47s, but a light weight machined aluminum dome has always been preferred. Weight is an issue, especially with foamies, as you can imagine.

Best,

Dave

DG,

So, if I increase the "gap" at the base to 0.5" from 0.375" and decrease the threaded portion to 0.5" from 1.0" it's a go?

And you think the profile is good to go as well?

Best, LB

[davegee]

Grossman56,
Glad your back. We finished out our basement a few years ago and having the outlets where I need them makes a job go smoother.

Elbee, your spinner looks great, thanks for stepping up and designing a 3d spinner. It has to be a lot lighter than my aluminum. I have included a drawing with Dave and My measurements, the spinner screws on the motor shaft and fits hand tight against the propellor hub. A recessed opening 3/8" deep allows the prop washer and nut to fit inside the spinner. Our measurements fit and look well on the FMS P-47. If my drawing is hard to read, please advise.





Best Regards, Rex

Hi Elbee: I think I can chime in a bit and Rex can add anything he wants to, since I have been using these for several years. The M10 nut screws tight with a wrench onto the threaded prop motor shaft. That's what keeps the propeller and its hub attached to the airplane.The simulated Curtiss Electric prop dome is recessed about 1/2" or so to clear the nut affixed on the prop shaft. The Curtiss prop dome is also threaded to hand-tighten onto the threaded prop shaft but really doesn't have any structural strength (at least as a printed part to keeping the propeller in place on the shaft in flight.)

Working with my contact on the East coast a few years ago, we never really came up with a satisfactory profile design as good as you have come up with to mimic the Curtis Electric prop dome. I still fly my printed dome on one of my P-47s, but a light weight machined aluminum dome has always been preferred. Weight is an issue, especially with foamies, as you can imagine.

Best,

Dave

[Elbee]

So the prop hub is functional, i.e., it is what keeps the propeller on the motor?

Or do you use a M10 to secure the prop and the Prop Hub simply threads onto the shaft?

[jetfool]

Grossman56,
Glad your back. We finished out our basement a few years ago and having the outlets where I need them makes a job go smoother.

Elbee, your spinner looks great, thanks for stepping up and designing a 3d spinner. It has to be a lot lighter than my aluminum. I have included a drawing with Dave and My measurements, the spinner screws on the motor shaft and fits hand tight against the propellor hub. A recessed opening 3/8" deep allows the prop washer and nut to fit inside the spinner. Our measurements fit and look well on the FMS P-47. If my drawing is hard to read, please advise.





Best Regards, Rex

[Grossman56]

I'd forgotten about the angled battery mount on the P 47. I'm thinking you might try what I've done to my P51, even though is sits flat. I ran a strip of industrial strength Velcro on the tray and those suckers don't move! It's almost painful to separate battery from tray, but you get used to it.
That way you could reposition the battery to correct the CG.

Grossman56
(Dangerous Dan)

[Grossman56]

Holy, has it been this long since I've been on here?
Yep apparently so. First of all, condolences Dave and Gail for your loss, pretty cool about the RV8's. We've been wrapped up in some upgrades to the basement and of course yardwork. Finally getting the basement framed in and I actually have electrical outlets!!!! No more running extension cords!
Got out to the field and lost my Blue Angels Bearcat but found out that the ol' DX8 has given up the ghost. It may explain a few other incidents though. A new RX8 is on the way.

Grossman56
(Dangerous Dan)

[Elbee]

jetfool

Here's a pic of the printed PLA Curtis Prop Hub.

The dimensions 22mm X 42mm can easily be altered in diameter and length.

I think the 'bullet' shape is good, but you be the judge.

That can be altered as well.

Additionally, any attachment setup, i.e., threaded or whatever could be used.

I'd need to know how you're attaching the current hub to the prop shaft.

Best, LB

[Elbee]

jetfool

Rex,

Just a quick look at the design.

I defaulted to the picture, you be the judge.

I shrank the diameter a smidge, but I believe I should go back to the original now that I see the comparisons.

Let me know what you think.

Best, LB

[jetfool]

Yes,
Elbee I can do that. Give me a few days to finish my 2nd versions.
Thanks, Rex