Cox Black Widow .049 Question?

coxxoc Wed May 09, 2012 8:11 am

Hi lads,

Would you guys fit it with a 1702 high compression head for better performance?
plus it looks great with it. I want the inside to have some serious RPM`s!!!
I plan to run it on 1/2 A fuel and a Cox 5x3 or 4.5x4 Thimble Drome prop. (Competition Series)
Cox Factory Parts Cat. #1702 .049/.051 Glow Head High Compression $12.59

Mr G Flying

John Goddard Wed May 09, 2012 1:21 pm

Depends how much you have burning a hole in your pocket
G.
If you look at my thread Raw Power which started life as a bit
Of a leg pull, it'll give you links to my utube.
Several bucks And blown up engines later I've got a reliable
(talk about tempting fate) 22,000 rpm out of a bee type motor.
It's all available from Bernie at Cox ca int and using freshly made
Fuel I know there's more to come.
Best
J
To answer your question
Yes you'll get at least 500 increase prob more
Don't forget though, add one head gasket for every
10% nitro
Pps
If you search black widow using the search function on the home page
Rusty has just about the most definitive 'how to'
With the B/W

**RknRusty** Wed May 09, 2012 6:36 pm

The racers are mostly the only ones that use a smaller than 5" props on a BW, and those engines are expected to be spent after a short life. The fastest turning props I've ever seen are APCs. My hotrod BW turns a 6x2 APC over 20,000 RPM on the bench. I just have a standard Bee crank in it.
APC 5.5x2 - 21,500
APC 5.5x2.5 - 18,300
APC 6x2 - 20,300
Master Airscrew 6x3 - 16,300

microflitedude Wed May 09, 2012 7:10 pm

I had a considerable decrease in RPM when I used a 1702 head on my Killer Bee. The standard head seemed to do fine. Maybe my 1702 is bad. Huh...

coxxoc Wed May 09, 2012 9:10 pm

Thanks Rusty, John and microflitedude

Mr G Very Happy

**RknRusty** Wed May 09, 2012 10:43 pm

microflitedude wrote:I had a considerable decrease in RPM when I used a 1702 head on my Killer Bee. The standard head seemed to do fine. Maybe my 1702 is bad.

If it glows and doesn't leak compression, it should work. I put Bernie's 5 fin high compression heads on my almost-Killer Bee and my Black Widow and it woke both of them up considerably. I'm using about 3 shims. I run Glowplugboy fuel with extra castor in everything now. It continues to run smoother and needle better than Sig 25 and 35. Even the Tee Dee on the pressure bladder likes the GPBoy fuel.

And, you're quite welcome Coxx

**Admin** Wed May 09, 2012 11:05 pm

microflitedude wrote:I had a considerable decrease in RPM when I used a 1702 head on my Killer Bee. The standard head seemed to do fine. Maybe my 1702 is bad.

The Killer Bee originally came with a 1702 head! Try a different 1702.

Well, all of my Black Widows have high comp 1702 heads on them. They originally came with a 325 standard head. My black widows all seem to run great with a high compression head, they also run fine with a 325 head.

coxxoc Wed May 09, 2012 11:21 pm

Thanks Rusty and Admin!

Mr G cheers

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