Atom 80 thrust

[VaidotasR]

I'm looking for some real life thrust numbers of Atom80 engine. Are those numbers in manufacturer site close to reality? 

Thinking it would be nice to swap my current motor raket120 with atom80, but not sure about the benefits.

[Bob27]

The atom 80 has a little bit more thrust than the racket, but not much and I think it is a little quieter. Other than that, they are nearly identical in every other category including weight and fuel consumption. The one advantage of the Radne is that it is very reliable and needs less maintenance than the atom 80 due to the lower power to displacement ratio, But the atom is also nice as you don´t need to deal with the decompression valve and i think it is a little more consistent in performance. 

If cost is not an issue an atom would be a good upgrade, but if your radne is working good, I would probably stick with it.

[RickH]

I measured my new ( 35hrs ) Atom80 with 130cm prop as having 44kg of thrust, well less than the 55kg claimed. my engine is only pulling 9500rpm, not 9800rpm so that may affect max thrust?

[VaidotasR]

My Raket also have 44kg of thrust at 8300rps and 1,3m eprops propeller. 3,3lph.

I want a bit more, around 55-60kg of measured thrust, light and economic engine. 

If not an Atom80, then what?

EOS? Not reliable...

Moster? Way heavier and thirsty.

Thor 130 evo? 60kg thrust. Anybody know fuel consumption numbers?

Sky110s?

 

RickH: I don't think 300rpm would give more than a few kg of thrust.

Edited February 14, 2021 by VaidotasR

[Bob27]

I recently ported and polished a radne 120 along with ceramic coating the cylinder head and piston. I also removed some access casting material saving about 200 grams of weight.

During a thrust test it came in at 85lbs (38kg) thrust, but I am 5000 feet above sea level. Based on other engines we have tested at both 5000' and sea level, this would equate to over 110lbs (50kg) measured thrust at sea level. I still haven't tuned the carb after porting the engine so I expect it is capable of even more than that.

I am going to switch to a Minari 200cc or electric so my ported radne is for sale.

[VaidotasR]

On 14/02/2021 at 21:05, Bob27 said:

I recently ported and polished a radne 120 along with ceramic coating the cylinder head and piston. I also removed some access casting material saving about 200 grams of weight.

During a thrust test it came in at 85lbs (38kg) thrust, but I am 5000 feet above sea level. Based on other engines we have tested at both 5000' and sea level, this would equate to over 110lbs (50kg) measured thrust at sea level. I still haven't tuned the carb after porting the engine so I expect it is capable of even more than that.

I am going to switch to a Minari 200cc or electric so my ported radne is for sale.

Can you tell me where the raket cylinder needs to be modified? What is the thrust gain?

[Bob27]

during the one thrust test we did with it, we saw roughly a 13% increase in thrust over the stock engine. 

(As a heads up, I am not the best at describing obscure parts of 2 stroke ports)

I did many modifications to the engine. Here are some of the modifications I can remember right off the bat: widened intake port window, exhaust port raised to give 5 more degrees blowdown, reshaped transfer port ¨intake¨ window for better flow, lightened piston, all ports polished with ¨texture¨ then added to the intake and transfer ports, Piston windows opened and smoothed, all sharp edges of port windows smoothed to lengthen piston ring life, thermal ceramic coating added to cylinder head, piston crown, and exhaust port, exhaust port rounded for better piston ring life, and any other place where something could be reshaped within reason for better flow or extended piston ring life it was done.

There are still some modifications I would like to do. For example my dremel tool couldn´t fit in to alter the transfer port windows which I would really like to open up and reshape. I would also like to either make a new expansion chamber or modify a 125cc 2 stroke motorcycle expansion chamber to use for this engine. The stock one is so tamely tuned that it is nearly useless, so a new one should give at least 20 percent more thrust with the only real limit being how much cruising efficiency I am willing to sacrifice.

 

I would only recommend modifying your engine if you are experience with porting 2 strokes. On every step I did, I could have destroyed the engine if I made a mistake. One must also have a vast understanding of their working principles in order to optimize one without throwing any part off balance which would quickly destroy any performance that you may have hoped to gain.