Brad5312 Posted October 8, 2018 Share Posted October 8, 2018 Hi all, any one one know how to apply tension to the belt on a rad arrow? Photos attached. Quote Link to comment Share on other sites More sharing options...
alan_k Posted October 8, 2018 Share Posted October 8, 2018 Looks like washers under the cylinder block to raise/lower it off the mounting bracket. Quote Link to comment Share on other sites More sharing options...
cas_whitmore Posted October 8, 2018 Share Posted October 8, 2018 If I remember right . The bottom shaft is eccentric ,so you have turn the shaft to adjust belt tension . cas . Quote Link to comment Share on other sites More sharing options...
AndyB Posted October 8, 2018 Share Posted October 8, 2018 There is also a clever way of getting the correct tension by twanging the belt at its mid point and using a phone app to listen to what frequency the twang is. Then adjust to get the correct frequency (370 Hz on my machine). This works incredibly well. Quote Link to comment Share on other sites More sharing options...
e2vdavidb Posted October 9, 2018 Share Posted October 9, 2018 Twang the belt to check tension! ok I'm game whats the app and how do I get the correct frequency for my Moster.... Quote Link to comment Share on other sites More sharing options...
e2vdavidb Posted October 9, 2018 Share Posted October 9, 2018 Ok I was being super lazy, quick search and I found an old post with link. Here is the app info, its free so worth a punt. http://www.custom-air.co.uk/Custom_Air_Paramotors/paramotor_files_nitro_engine_belt_tension_setting.html Good luck. Dave Quote Link to comment Share on other sites More sharing options...
AndyB Posted October 9, 2018 Share Posted October 9, 2018 That's it. I found it really accurate...which it should be as the frequency of vibration is directly determined by the tension of the belt and the free length of belt ! Quote Link to comment Share on other sites More sharing options...
e2vdavidb Posted October 13, 2018 Share Posted October 13, 2018 Ok actual did it today with my Moster Plus. Factory says use a 4kg counterweight if no frequency counter is available so I did both to see how they compare. The frequency method has much higher resolution than a 4kg weight to be sure so app installed I now have a very fast way to pre-flight the belt. FYI, belt at about 50 hours looks like new, no cracks or wear apparent. Starting frequency was 300Hz, well below the recommended 430-450Hz for the 13 tooth Moster plus. Vitorazi do have a very goo Youtube how to video that made it a 20 min job so easy. I used a bolt marker fluid, like green thick paint, to be able to make a visual check if anything moves. Also found my small torque wrench is one direction! Had to eyeball the reverse thread on refit. 1 Quote Link to comment Share on other sites More sharing options...
skydiverken Posted June 1, 2020 Share Posted June 1, 2020 Hello David Last week wr checked the belt tension from my friend his moster 185. it was only 150Hz. We adjusted the tension by using an app to measure the frequency, to 450Hz. After a flight (45min) we checked again after the engine had cooled down. The frequency was only 350 Hz. Does anyone know this is normal, I think not but we put nail polish on the bols and nothing had moved. Quote Link to comment Share on other sites More sharing options...
AndyB Posted June 1, 2020 Share Posted June 1, 2020 After flying the belt will be warm.....and just ever so slightly longer. Hence tension will be less. The tension settings are usually to be done when cold. Quote Link to comment Share on other sites More sharing options...
skydiverken Posted June 1, 2020 Share Posted June 1, 2020 Hello Andy, thank you for your reply. We tensioned the belt when the engine was cold and we waited about one hour after the flight to remeasure the belt tension. Quote Link to comment Share on other sites More sharing options...
AndyB Posted June 1, 2020 Share Posted June 1, 2020 I assume it is the grooved type of belt? It was probably just settling back in to its new tension then. After it had been quite loose it is likely the rubber was rubbed on the inside. After running much tighter for a while the grooves will have been better pushed into the pulley grooves. I usually find I set mine (Nitro) at 370 and it drops to 350 straight away. Quote Link to comment Share on other sites More sharing options...
skydiverken Posted June 2, 2020 Share Posted June 2, 2020 Hello Andy, thxs again for your reply. Yesterday we did another flight. After two beers, the engine cooled down and we checked the tension. It was 350Hz again. Guess its ok. 1 Quote Link to comment Share on other sites More sharing options...
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