wallboy Posted March 7, 2012 Share Posted March 7, 2012 I currently fly a Rad Mxl which has a 110cm cage but I am looking to convert it to a 140cm cage so I can fit a 130cm prop. I am looking to remove the outer part of the frame and get a pipe fabricator to role me a 140cm diameter cage which can be welded in its place. I would also need someone to make a box frame for under the harness so it can sit on the floor properly. Am I right in thinking that if I remove the 3 bladed prop, all I would need to fit a 130cm prop is a spacer, 6 bolts and a prop plate? If this is correct, where can I get these parts from? (preferably from the UK) Quote Link to comment Share on other sites More sharing options...
nigel_d. Posted March 7, 2012 Share Posted March 7, 2012 Cant help much but check the reduction ratio is suitable for whatever prop you fit. I think the rad arrows which you might be thinking of copying have a reduction system made by Radne in Sweden and are bound to be different to the reduction you currently have which originated in Oxford. You could always flog it and buy my Pap 1400 top80 instead! (£1900) Nige ps welcome to the group. Quote Link to comment Share on other sites More sharing options...
pete_b Posted March 7, 2012 Share Posted March 7, 2012 Cant help much but check the reduction ratio is suitable for whatever prop you fit. I think the rad arrows which you might be thinking of copying have a reduction system made by Radne in Sweden and are bound to be different to the reduction you currently have which originated in Oxford.You could always flog it and buy my Pap 1400 top80 instead! (£1900) Nige ps welcome to the group. you will need a different ratio. Give Norris a shout or PM, he has just done what you what to do and fitted low hang point weight shift bars. Pete Quote Link to comment Share on other sites More sharing options...
wallboy Posted March 7, 2012 Author Share Posted March 7, 2012 Cant help much but check the reduction ratio is suitable for whatever prop you fit. I think the rad arrows which you might be thinking of copying have a reduction system made by Radne in Sweden and are bound to be different to the reduction you currently have which originated in Oxford.You could always flog it and buy my Pap 1400 top80 instead! (£1900) Nige ps welcome to the group. Thanks for that and if I had £1900 I would buy it but sadly I dont hence wanting to alter my current Rad Quote Link to comment Share on other sites More sharing options...
wallboy Posted March 7, 2012 Author Share Posted March 7, 2012 Cant help much but check the reduction ratio is suitable for whatever prop you fit. I think the rad arrows which you might be thinking of copying have a reduction system made by Radne in Sweden and are bound to be different to the reduction you currently have which originated in Oxford.You could always flog it and buy my Pap 1400 top80 instead! (£1900) Nige ps welcome to the group. you will need a different ratio. Give Norris a shout or PM, he has just done what you what to do and fitted low hang point weight shift bars. Pete Brilliant, thank you. I will go hunt him down. Quote Link to comment Share on other sites More sharing options...
wallboy Posted March 8, 2012 Author Share Posted March 8, 2012 Cant help much but check the reduction ratio is suitable for whatever prop you fit. I think the rad arrows which you might be thinking of copying have a reduction system made by Radne in Sweden and are bound to be different to the reduction you currently have which originated in Oxford.You could always flog it and buy my Pap 1400 top80 instead! (£1900) Nige ps welcome to the group. How do I check the reduction ratio for a new prop? Quote Link to comment Share on other sites More sharing options...
nigel_d. Posted March 8, 2012 Share Posted March 8, 2012 Measure the pulley diameters and divide the larger by the smaller, it might be 3.5/1 or whatever. If the prop you had in mind was the 2 bladed one used on the rad arrow then you would need to know the ratio for the reduction used on that machine and hope it is the same. Hope that helps. Nige Quote Link to comment Share on other sites More sharing options...
wallboy Posted March 9, 2012 Author Share Posted March 9, 2012 Measure the pulley diameters and divide the larger by the smaller, it might be 3.5/1 or whatever. If the prop you had in mind was the 2 bladed one used on the rad arrow then you would need to know the ratio for the reduction used on that machine and hope it is the same.Hope that helps. Nige OK, so the small pulley is 1.5" and the large is 7". I dont have any prop in mind, all im looking for is any prop which will produce more thrust than the 18" bendy plastic tri prop which I currently have So now what do I need to do to work out what prop I need? Why can I not just get any prop which has the same bolt holes? Sorry but im not into this technical stuff Quote Link to comment Share on other sites More sharing options...
nigel_d. Posted March 9, 2012 Share Posted March 9, 2012 4.6 recurring to 1, hmm... What you want then is the results of someone elses previous experimentation with different props. In order for the prop to get optimum power from the engine, ie reving to about 9500, the pitch and other dimensions need to be just right so unless you have access to several different props you need to know which one works. best of luck with your research. Nige Quote Link to comment Share on other sites More sharing options...
wallboy Posted March 9, 2012 Author Share Posted March 9, 2012 4.6 recurring to 1, hmm...What you want then is the results of someone elses previous experimentation with different props. In order for the prop to get optimum power from the engine, ie reving to about 9500, the pitch and other dimensions need to be just right so unless you have access to several different props you need to know which one works. best of luck with your research. Nige Oh great lol I use to have a PAP which had the Racket engine with a 130 prop which I sold. I have been in touch with the new owner and he tells me hes using a 130 Helix prop which is designed for a 1:4 ratio and he has a 45mm drive and 180mm prop. Mind however is 40mm drive and 180mm prop. Do you think I could get away with my current ratio and just stick a 1:4 ratio prop on? Quote Link to comment Share on other sites More sharing options...
nigel_d. Posted March 9, 2012 Share Posted March 9, 2012 Only try it if you can borrow such a prop and have a rev counter to check it. To give you some idea try adjusting the pitch slighly on your tri-blade and see how much it affects rpm, but more importantly how critical it is trying to get it back! Nige Quote Link to comment Share on other sites More sharing options...
nigel_d. Posted March 9, 2012 Share Posted March 9, 2012 ...forgot to mention, It took 7 years of owning an MXL before I realized you cant polish a turd.. Quote Link to comment Share on other sites More sharing options...
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