NIC - Maybe not so much HP in general, but HIGH power to weight ratios. The last 1/10th scale R/C off-road truck we raced had 1.5 HP # 32,000 RPM from 1/8th of a cubic inch displacement, truck weighed 5-1/4# on the starting line, so 3.5#/HP.
The 1/8th scale 4WD buggy SON raced this summer weighed right at 8# ready to race, with just a tic over 2-1/2 HP @ 35,000 RPM. from 1/5th of a cubic inch displacement. So 3.2#/hp, And the buggy will run 60+ MPH actual speed if you gear it right, runs 40-45 with race gearing.
Ohhh and the tires on those R/C cars did NOT have inner tubes... we glue the molded rubber tires to the injection molded plastic wheels with CA glue. We do use molded foam liners to give them some "body".
HARRY - I think the last time we had the inner tube debate you were involved in a tail light lens debate on what the proper numbers molded into the lens was/were, or maybe it was the proper shape, size, & form of a heat shield for Q/L CC's.
MIKE F. - I use about 78% nitrogen in my tires, maybe just a hair less, with a higher percentage of CO & CO2, depends on what I've had running in the shop before I turn on my air compressor.
I did have a gas supplier call me on a "Cold Sales call" 30+ yrs ago, wanted to sell me a 45,000# semi-truck load of commercial grade compressed Nitrogen gas. When he asked me what we made, and I said Automobile shredder rotors and other steel scrap recycling equipment, He said, "Doesn't sound like you use or need any Nitrogen.." and hung up.
I guess we could all fill all our tires with Redi-Whip, they use Nitrous-Oxide as the propellant, but as N2O, it's not quite as high in nitrogen as the common atmosphere, just higher in oxygen, 33% vs 21% in air. And if we got as leak in our tires, we'd act all goofy and laugh uncontrollably.