Prop Shaft on Fox 35

I recently ran into a problem with trying to mount a Great Planes 1 3/4 plastic spinner on a Fox 35. When you put the spinner backplate on and then mount either an APC or Master Airscrew prop on the shaft, there is not enough threads left to put the prop nut on and tighten it. This is the first time I have run into this problem since I normally do not use Fox engines. Is this common and if so what is the solution short of putting another engine on the plane which I really don't want to do.

Thanks

Mike

Appears that you need a Union Nut. The nut will thread over the current prop shaft thus extending the shaft. You will however have to ream the prop to the outer diameter of the union nut. Fox sells them as part of there extension shaft kits. You may need to shorten the nut to suit your particular spinner. There is a good chance you can find union nuts at a hardware store but I've never searched so I don't know for sure

Mike (F),

It may be possible to find a 1/4-28 union nut, but I doubt you'd find one with a short hex end, and the rest turned down to 5/16" or 3/8" diameter.

Right, though, Fox Mfg sells shaft extension sets, which include a shaft extension spool, the union nut and the correct size front washer. The steel version comes with a 5/16" shank, 1/2" or 3/4" long spool and the appropriate "shank" (by which I mean the length turned cylindrical, behind the hex end.) The steel item also has a smaller hex wrench size than the aluminum item which has a 3/8" 'shank' diameter.

These are small enough that the weight difference between steel and aluminum is negligible, and the smaller diameter you need to ream the prop to, for the steel piece, leaves the prop a bit stronger.

Both adapters are tapped for a smaller spinner center bolt at the front end. Using a plastic type spinner, with two bolts through to its backplate, makes that front thread irrelevant.

Mike, you may need to shorten the shaped union/extension nut so it doesn't bottom out, but with the 1/2" extension, probably not. For a Fox 35, make sure the prop and spinner are well balanced. Shaft extensions can really increase wear on the shaft main bearing...

If you're going to use a plastic spinner, do yourself a favor and order the Great Planes nylon ones with the aluminum backplate, which is much thinner than the plastic backplates. Pretty much solves the problem.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBMX7&P=7

If that doesn't quite do it, Dave Brown has a 1/4-28 nut that is stepped, and the matching washer is bored through for that step, so the nut goes into the washer. Here's the idea, and it would work, but it's not the ideal part. You could cut off some of the snout and make it correct.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXB952&P=7

Another way to reduce or eliminate the problem is to change to a Thunder Tiger prop, which work quite well if the correct size is available. TT makes a 10-5.5 that should do fine on a Fox .35 Stunt.
Steve

Steve Helmick
Renton, Washington
USA

I would never use a apc prop on a Fox. .35 or common composite prop. Woodies work well with Fox's. Never had a problem with a spinner and a Fox, unless someone made shaft shorter. Like some one said get a differt spinner. I gave away all my larger apc props and fond that the smaller ones were decent. I kept my 7" and smaller ones.
Dan

What is the problem with running APCs or other composite props on a Fox??

Bigiron

Hey Marvin,
APCs work great on Foxes as you surely know. Bollys and Eathers probably shouldn't be used because they cost more than the engines are worth...
OK, OK Just kidding!!!!
Personally I think the heavier props like APC work very well on Foxes. The extra weight of the prop and additional "flywheel" effect tends to smooth things out a little and minimizes the "Burp" if necessary.

Randy C

I well know that Randy. I was just wondering why Dankar said to never run an APC or other composite prop on a Fox 35. Thought I might learn something.

Bigiron

Marvin,
Hmmmmm.....Well who knows??? Sure wish I'd had some back in the 70's when I was running Foxes seriously....

Randy C

This should look right familiar to you.

http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=307562&mesg_id=307562&listing_type=search

Seems like any of the 1/4-28 nuts work. The one our hobby shop had in stock said "Super Tigre", worked fine on the Brodak.

Larry Fulwider

[photo not recovered: clstunt.gif]Attachment #1, (clstunt file)

>I recently ran into a problem with trying to mount a Great
>Planes 1 3/4 plastic spinner on a Fox 35. When you put the
>spinner backplate on and then mount either an APC or Master
>Airscrew prop on the shaft, there is not enough threads left
>to put the prop nut on and tighten it. This is the first time
>I have run into this problem since I normally do not use Fox
>engines. Is this common and if so what is the solution short
>of putting another engine on the plane which I really don't
>want to do.
>
>Thanks
>
>Mike

try this one, they're sold at Brodak's

[photo not recovered: 29660.jpg]

http://www.brodak.com/shop_search.php?productsearch=extension+shaft

Attachment #1, (jpg file)

If you want just the extension net and not the complete shaft extension, I have several of both 1/2 and 3/4 inch lengths and also threaded both 1/4 X 28 all the way through or 1/4 X 28 most of the way through, but changing to 10 X 32 at the end for the spinners with that thread hold on screw.
Fof lists the entire assembly at $8.00 I will sell just the nut for $5.00 plus shipping

Thank you everybody for your replies and help. I solved the problem by doing what Walter suggested. This was the first time I had ever run into this and since I dont use Fox engines as a rule, didnt know where to turn to solve it.

That is what I love about this forum.

Thanks Guys

Mike

Tbanks for the info. I experienced the same problem with a Fox 36X. Ran if sans spinner then.