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Author Topic: Prop for Fox .15  (Read 3879 times)

Offline mike londke

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Prop for Fox .15
« on: January 06, 2016, 06:07:28 PM »
I don't have much experience with Fox .15's. A gentlemen Samuel met at Huntersville last fall saw him flying and said he would like to send some engines for him. We recently got a box with several .15's in it. Also a .29 and a .40. They all have good compression and seem like runners. They will be going on Akromasters, Jr Rings and JR Flite Streaks. I picked up some real beaters recently that we will bring back to life.  I need some prop recommendations for the .15's.  Preferably something to keep the planes on the slow side. Thx Mike
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Offline Bill Adair

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Re: Prop for Fox .15
« Reply #1 on: January 06, 2016, 06:30:07 PM »
Hi Mike,

Which Fox .15?

I have the .15X slant plug (2), and the engine reviews recommend a 7x4 for CL, or 8x3.5 for FF.

The hi-back schneurle ported .15 takes bigger props, and is more powerful.

http://sceptreflight.net/Model%20Engine%20Tests/Index.html

Note that the 15X has a compression reducing head spacer for sport flying. With that in place both mine take most long glow plugs, but one unknown plug in my used plug caddie causes the piston to hit that plug (no idea where that plug came from).

With the spacer removed, you would probably have to use short reach plugs.

Mine are both easy to start, and run well on the stock needle.

Bill

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Offline mike londke

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Re: Prop for Fox .15
« Reply #2 on: January 06, 2016, 07:02:09 PM »
Quote from: Bill Adair on January 06, 2016, 06:30:07 PM
Hi Mike,

Which Fox .15?

I have the .15X slant plug (2), and the engine reviews recommend a 7x4 for CL, or 8x3.5 for FF.

The hi-back schneurle ported .15 takes bigger props, and is more powerful.

http://sceptreflight.net/Model%20Engine%20Tests/Index.html

Note that the 15X has a compression reducing head spacer for sport flying. With that in place both mine take most long glow plugs, but one unknown plug in my used plug caddie causes the piston to hit that plug (no idea where that plug came from).

With the spacer removed, you would probably have to use short reach plugs.

Mine are both easy to start, and run well on the stock needle.

Bill


Sorry, I should have said which one.  They are stock, plain bearing. slant plugs. 2 bolt backplate.
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Offline bob whitney

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Re: Prop for Fox .15
« Reply #3 on: January 06, 2016, 07:19:27 PM »


 the spacer should have nothing to do with the plug hitting ,if it is hitting it is because it is sticking down too far i am pretty sure it uses a short plug
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Offline Bill Adair

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Re: Prop for Fox .15
« Reply #4 on: January 06, 2016, 09:46:15 PM »
Bob,

I agree that you should use short plugs as recommended by Fox.

Both of mine have long plugs installed by previous owners, and right or wrong they run fine that way.

I also rechecked the other long plugs I have on hand (a mix of Fireball, Fox, McCoy, Merlin, and who knows what else) and none of them contact the piston. Then I removed the plug washers, and checked again - still no contact!

So stick with short plugs to be absolutely safe.

Only use long plugs in a pinch, and only after checking clearance without the plug washer first. Then install a new plug washer, and check again.

Bill
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Offline frank mccune

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Re: Prop for Fox .15
« Reply #5 on: January 07, 2016, 08:38:50 AM »
     Hi Mike:

     I flew the Fox .15x for many many flights using a 7x6 or a 8x4 on a Shark 15!  I think that he 8x4 was a bit slower.  I also have a Sterling P-38 that I have two Fox 15x engines with 7x6 props mounted and it is very fast with this combination.

                                                                                                                               Good luck.

                                                                                                                                Frank McCune
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Offline BillP

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Re: Prop for Fox .15
« Reply #6 on: January 07, 2016, 10:18:27 AM »
8x4 on a Ringmaster Jr with the early steel fin plain bearing Fox 15 on 52' lines. It was just enough to keep the lines tight in calm winds. I flew it on 5% nitro but 15-25% is better according to my conversations with the Fox factory yrs back. Ran Fox standard short plugs and never tried longs in it.   
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Offline mike londke

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Re: Prop for Fox .15
« Reply #7 on: January 07, 2016, 10:39:35 AM »
Thanks for the replies.
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Offline Ken Burdick

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Re: Prop for Fox .15
« Reply #8 on: January 07, 2016, 03:27:41 PM »
yah,
don't worry about it going too fast.
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Offline mike londke

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Re: Prop for Fox .15
« Reply #9 on: January 07, 2016, 05:33:52 PM »
Quote from: Ken Burdick on January 07, 2016, 03:27:41 PM
yah,
don't worry about it going too fast.

I wanted to make sure they weren't too fast for Samuel, he's 7. :)
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Offline Terry Caron

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Re: Prop for Fox .15
« Reply #10 on: January 09, 2016, 07:31:46 PM »
I have plenty of props to try, Mike.
If the weather doesn't turn into a deep-freeze we can check 'em out.

Terry
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Offline GregArdill

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Re: Prop for Fox .15
« Reply #11 on: January 09, 2016, 07:45:26 PM »
My slant plug 15, in Acromaster swings an 8X4. On 52' lines.

Good sedate flier. Not the best model I have so it rarely gets an airing, but it'd good for someone with limited experience.
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