Dub Jett Engines Support Bob Brassel of Dub Jett Engines provides direct support here for Jett Engines.



Old 06-23-2009, 11:57 PM
Senior Member
Thread Starter
Join Date: Aug 2006
Location: peoria, AZ
Posts: 470
My Gallery
My Models
My Feedback
Default viper-60lx

hello bob, checked out the viper-60lx w/ gps a couple of times. 2 weeks ago i hit the 133 mark. on sat i hit the 154 mark. i am using a apc 9-8 prop w/ omega 15%- 4% caster. am tacking around 18000 and backing of 6-700 rpm. the engine still feels tight. i know it takes a while for the 60lx to break in. my question is what rpm am i shooting for as the engine breaks in? this prop seems to be the right choice for this setup. still blowing to many plugs. thanks, russ
russm is offline  
Reply With Quote
Old 06-25-2009, 10:42 AM
My Feedback: (19)
bob27s's Avatar
Join Date: Apr 2002
Location: Cleveland, OH
Posts: 5,576
My Gallery
My Models
My Feedback
Default RE: viper-60lx

RPM sounds perfect. 18K is the right number. The engine will not loosen up much as it runs more...... not intended to do that, so do not let the cold/warm compression fool you. Tight is good, and it sounds like the fit is there. Fit is perfect while running.

Plugs........ Ive played a bit with the H9 performance plugs. They work very well. If you are only going "fast" and not all that worried about transition, try a McCoy 9

Another quick test to play with ...... install a second washer under the plug. See if tha helps.

Question - do you have the needle valve airframe mounted? (likely if you have a backplate mounted engine).

Props to try 8.5x7.25, 8.5x7.5 8.75x8W 8.8x8.5
Peak rpm will vary with these. Dont worry a great deal. Just ensure that you launch off peak as you have been. The engine and muffler will find the rpm they want once in flight.
bob27s is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service