I'm not sure the posts DO recommend the use of hot plugs for high nitro-the principle of hot vs cool for low and high nitro fuels has been long established for decades. Small engines are at a thermodynamic disadvantage compared to large ones in that their surface;volume ratio is high and so they lose heat faster than large ones-this is the basic reason why the smaller engines-049s and smaller require higher nitro levels just for normal running-and the smaller you go the higher the nitro (within limits)-eg a Babe Bee will run on 10% or 15%, a Pee Wee will be less than happy on this and a TD .010 will be reluctant to run at all-up the nitro to 25% or 30% and they'll all sing-but 25% is a bit of overkill for a sport 049.
Conversely this same adverse surface:volume ratio is why you rarely hear of 1/2A engines having cooling problems in use-unlike larger R/C engines or cowled C/L ones...

GloBees were good-but required a ton of power to drive them-at least 2V-which would fry a normal cox head if you forgot what was installed. The use of normal plugs in a Cox head adapter ALWAYS results in a significant loss of power-there's no escaping it-and for several reasons. The use of clamped inserts and Nelson plugs is less problematic-and some of these exceed the performance of the standard head.

The achilles heel of Cox engines is the ball and socket little end-and this is probably the only real reason why castor is preferred-its film strength is unequalled in this role-which is an extreme loading from a lubrication point of view-in direct contact with the piston crown-so the hottest part of the engine, largely shielded from the incoming cool fuel mixture due to the retaining cup, and subjected to rapid load reversals every cycle-if the Cox used a normal gudgeon pin it would be quite happy on all synthetic. Most commercial 1/2A fuels ARE synthetic with a bit of castor......

ChrisM
'ffkiwi'