I decided to get back into control line after wandering into RC for a few years. I bought a Cox Hyper Viper just to get my chops back up. It actually doesn't fly too bad, but it needs a little more engine.

It appears to be a standard .049, and my question is this. I have a brand new Black Widow .049, which is supposed to be more powerful. In looking at the list of parts, it looks like the only difference in the two is the cylinder. Can I just swap cylinders to get more power.

Also, it came with a 5x3. Is that at good prop choice?

Thanks,
Jim

Jim:

Yes, you can swap the cylinders, but it's possible the intake bore is a different size also.

The 5x3 should do well.

Bil.

One other thing you may want to do to make it fly better is change the lines if you are using the Dacron lines / plastic handle.
Get a set of .008 lines and an adjustable handle, ( the Cox one doesn't fit my hand right). Another option is Spyder wire fishing line, it is stronger and has less drag than the supplied Dacron lines.
Using 25% nitro is also helpful for increased power and better runs from 1/2A engines.

A better choice might be just mounting the BW engine to the back plate of the motor in the Hyper Viper.

Sorry folks, there will be essentially no power difference by bolting on the BW front end. The key to Hyper Viper performance is to drill out the venturi to .156 (5/32"), use 30% Nitro, and either the .008 lines mentioned or lightweigh Spiderwire fishing line.

Then, you might go to the High Compression (1702) head or a Norvel Freedom plug and play with head gaskets until you get a steady run.

An old (taper ground and honed) Tee Dee piston and cylinder set will then make more difference, and also try the APC 5.7x3 prop.