Re: Cox prop question

roddie Mon Sep 01, 2014 1:37 pm

Cox International wrote:Yes, of course, downstroke lol.

That's what happens when I drop into the office on a holiday Monday

I was expecting you to reply-back; telling me to go "make you a sandwich" and then stand in the corner for awhile.. Smile

sdjjadk Thu Sep 04, 2014 9:45 pm

1/2A Nut wrote:Hey guys cox made some CL dog fighters meant to be combat with streamers here is the triplane with a reed .049 note the prop size 4.0D x 2P written on the other blade of this RH prop is the word COX
The prop dia is suits the plane as the wee lil plane is small like a Lil Stinker.
The cylinder has the twin slits I would imagine to help protect the plastic. Very interesting prop choice and without question the least amount of prop pitch in relation to diameter ever mass produced for a cox .049 reed engine. This engine has to pull a streamer and must screaaam with this prop - have not ran it as of yet I would guess 25k ish. unloaded. If anyone has flown the biplane or the triplane let me know I would like to hear how well it did.

I have owned a couple of the DR-1's and I have owned a couple of the Sopwith's and they all flew great! They were super stable and easy to fly but yet maneuverable enough to easily perform loops.
It's a little dusty, but here are a couple of pics of my never flown DR-1 from the 70's with the original 4.5x4 faux wood grain prop.

The faux wood grain props came on the Dog Fighter Series planes back in the 70's and they re-released them back in the 90's with the same style prop but in black.

Also, Bernie sells the direct replacement L.H. props for the Dogfighter Series.
http://coxengines.ca/cox-.049-propeller-4.5-x-4-left-hand.html

Shawn

**RknRusty** Thu Sep 04, 2014 10:05 pm

I've always loved a DR1 Tripe. My best build as a kid was a static model when we were studying WW1. My history teacher LOST it! GRrrrrr!

1/2A Nut Thu Sep 04, 2014 11:47 pm

Yes I have some of those sexy wood looking and black swept right hand props.
I wonder where this prop came from then 4 x 2 seems best for a .020??
Perhaps they used this at some point to improve ground clearance.

1/2A Nut Sun Sep 14, 2014 5:37 pm

Hey Bernie has the folks in California started a run yet?

Paranoid

Cox International Mon Sep 15, 2014 11:07 am

1/2A Nut wrote:Hey Bernie has the folks in California started a run yet?

No idea. Once they run them it only takes a few hours for 2,000 props.

They have to squeeze this miniscule production run in between two "real" production runs.

Cox International Thu Sep 25, 2014 1:39 pm

The props were shipped today and should arrive in aprx. 10 days Smile

batjac Thu Sep 25, 2014 1:42 pm

WooHoo! Now to select which plane gets one first.

The Excited Mark

Cox International Thu Sep 25, 2014 2:03 pm

Dilemma easily solved ... buy them in bulk lol!

1/2A Nut Thu Sep 25, 2014 2:46 pm

Wooot thank you for the update Bernie! Small Cox Logo

Cox International Tue Sep 30, 2014 3:26 pm

Here they are:

http://coxengines.ca/cox-.020-racing-propeller-4-x-2.5.html?&cat=44

and in 3-packs:

http://coxengines.ca/cox-.020-racing-propeller-4-x-2.5-3.html

batjac Wed Oct 01, 2014 12:05 am

Okay. My order's in...

The Early Adopter Mark

Cox International Wed Oct 01, 2014 9:00 am

batjac wrote:Okay. My order's in...

The Early Adopter Mark

Thanks and we received several orders overnight Smile

1/2A Nut Wed Oct 01, 2014 7:58 pm

Good idea with the multi 3 packs!!
I just made a double order along with some other needed goodies. Small Cox Logo

WTG Bernie,
Let us know if you decide to go with a run of the competition greys the material is great for reworking / shaping with a fine file and buffs up to a shine.

Example done with the 3 x 1.25

batjac Wed Oct 01, 2014 8:54 pm

1/2A Nut wrote:
WTG Bernie,
Let us know if you decide to go with a run of the competition greys the material is great for reworking / shaping with a fine file and buffs up to a shine.

Example done with the 3 x 1.25

Do you get a measurable difference in thrust doing this? And how do you determine the shape to file? Using an APC as a template?

The Curious Mark

1/2A Nut Wed Oct 01, 2014 9:33 pm

Hi Mark,

I have been prop shaping for years, I also like to scratch build all my planes so the custom bug is always biting.
The trick is take a photo of the prop then put it in paint or some photoshop type application and simply draw out the curves that look right for your needs. Next you get some paper packing tape on one blades and copy draw on the lines you liked. Cut out with sharp medium size curved cuticle type scissors / remove the tape and match it up on the uncut blade the rest is all in the shaping work file in the foil and buff to a shine with fine sandpaper use the same technique in your shaping style for both blades you will be surprised what you can do by hand. After you're done and you feel your best efforts have been made to match up the work on both blades (balance the prop) and fine tune some material off the heavy side.
The prop shown took me less than 30mins (being so small) from design to finished prop.

The modified modernized prop puts out more rpm it is still a 3in dia prop providing good thrust yet the swept (sharper) leading edge increases the rpm and the relief in the trailing edge of the tips expound the rpm even further for the TD .010 this made for a huge jump in rpm depending on the nitro content you can expect a 1,800 to 3,000 + rpm increase over the stock prop. Cool

The plastic flexible props are not easy to shape you have to really want a robust prop to endure the extra shaping work.
The 3.3 x 2 is a hard glass/plastic prop easy to shape.

Kim Thu Oct 02, 2014 6:17 am

Cox International wrote:
batjac wrote:Okay. My order's in...

The Early Adopter Mark

Thanks and we received several orders overnight

Getting mine together also...waiting on my bud to decide what he wants me to add to the order...

batjac Mon Oct 06, 2014 10:35 pm

My package from Bernie came today. Lookee what was inside!

Cox prop question - Page 3 DSCN2307_zpsa528aee2

The Taunting Mark

1/2A Nut Mon Oct 06, 2014 11:28 pm

Braaap Braaaaaaap sizzle, great pic!

You and other folks should tune in with some feedback once you try one out. I already know the magic they can make with .020 engines. We have all been stuck with 2P the 3 blade 2.5P doesn't put out the rpm so you should be surprised how well the needle sets and extra provided pep of the 2 blade. Popcorn

1/2A Nut Sun Oct 12, 2014 9:09 pm

Thanks to Bernie and his resources I have recieved my props.

Here is a tip the rubber .020 spinner has enough diameter to cover the larger prop hub of the 4x2.5 if you don't want rubber you can take a .049 aluminum spinner and file or with a grinding wheel reducing just the nose feathering it in to suit the long version .020 prop screw. Once done it take on the same shape as the Queen Bee spinner.
Shown here in a pic the length of the .049 spinner is reduced some to be closer to the .020 stock aluminum spinner. The dia is spot on for this prop. Also note the stock screw is too short for this prop when used with a rubber spinner adapter you will have to use a stock prop screw.

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Cox prop question