Again back to softwqare calculations. And even measuring thrust with fish scales isn't overly reliable.

So the "constant" is the prop and the measurable variable is RPM.

SO wether a ZDZ will produce 36.79 lbs of STATIC thrust is irrelevant...

If it spins a 22x10 at 7300 (which I do not doubt for one instant) and the 58 Spins the SAME prop about the same... then it raltes the fact the the mystriously powerful 58 is indeed... a 60cc class engine and certainly does NOT provide the equivilent thrust of a ZDZ80 that spins a 4" bigger prop.

Look... we all want the most thrust for the lowest weight (unless you are building a warbird) What I am getting at is that it is evident that people will believe whatever they WANT to in order to complaete the "perfect picture". And while I could very well be wrong... I doubt very seriously that the 58 is anywhere CLOSE the usable power output of a ZDZ80. Meaning down and outright thrust.

If you want a semi-accurate method of comapring, then ThrustHP is a good tool cor comparison... it is completely accurate? Perhaps not, but it stand to reason it calculates everything with the same level of innaccuracy, meaning you can compare the numbers to get an idea of what the differences are between engines.

Horizon's "Benchmark" 24x10 Mens prop at 6900 calculate in ThrustHP as 46.04

RCShowcases stated ZDZ80 (not super) info is 26x10 Mens 6500 rpm and calcs at 56.28

IF these engines spin these props as stated, the it's easy to see that the "Regular 80" is approximately 25% stronger than the 58 regardless of what the real world thrust is.

I've been watching some of the reports of fish scale results and calcing them with Thrust calc... if there is some trend, it apperas real worl "fish scale" pull is about 2/3's of what it calc.

If THAT relates then the 58 will produce real world thrust of about 31 lbs... the 80 about 38...

If you have a 33% plane that weighs say 24 lbs, then you may be dissapointed with 1.3:1 power to weight ratio as compared to 1.6 to one. And if you can have either at very close to the same weight... which do you choose? Which would you consider the better choice for the plane?


But on a 50cc plane that comes in at 16.5 lbs with a DA50 and I KNOW that it spins a 23x8 @ 7150 rpm calcing 41.70lbs... you get about 28 lbs of thrust and a 1.7:1 thrusts to weight ratio.

Where as the same plane with the 58 will be at LEAST 1.5 lbs heavier or 18 lbs with a 1.72:1 thrust to weight ratio.

So again, I ask you... which is the better choice... nearly identical power generated, but the wingloading will be significantly different.

O.K., I've whipped up a good deal of mumbo jumbo here myself.

But again the theory is sound in that what a motor spins a particular prop at is the comparison factor. And until I see verifyable reports of the 58's RPM with what props I can't really make a final judgement... but at this point I take a doubtful view that the 58 is the powerhouse it is reported to be. I think it is a fine 60cc engine putting out approximately what a 60cc should, but being 1.5 lbs heavier than a DA50, and considerably less powerful than a ZDZ80 that it fills a niche where planes do not exist... at this point anyway.

As is the case with this particular aircraft, I can't see why it is rated for 50-80cc engines... they are so in a diffferent league that it's like saying an airframe is a 100cc-150cc airframe.

Ah well... all conjecture and mumbo jumbo... let us know when you get your engine running what it spins and how fast...