duncan_burdorf Posted August 7, 2010 Share Posted August 7, 2010 Can anyone clarify if the following change is a worry? PAP F200 with: standard (3 blade) carbon prop = 1400 RPM @ Idle Wooden (2 blade) prop = 1800 RPM @ Idle Is this something I should be worried about? I'm worried that with the new wooden prop the motor will exceed 8000 RPM and that the motor will overheat! Any suggestions? (Besides don't use full throttle!) Quote Link to comment Share on other sites More sharing options...
pete_b Posted August 7, 2010 Share Posted August 7, 2010 Can anyone clarify if the following change is a worry?PAP F200 with: standard (3 blade) carbon prop = 1400 RPM @ Idle Wooden (2 blade) prop = 1800 RPM @ Idle Is this something I should be worried about? I'm worried that with the new wooden prop the motor will exceed 8000 RPM and that the motor will overheat! Any suggestions? (Besides don't use full throttle!) you may have to change the reduction gearing Quote Link to comment Share on other sites More sharing options...
padeakin Posted August 8, 2010 Share Posted August 8, 2010 Can anyone clarify if the following change is a worry?PAP F200 with: standard (3 blade) carbon prop = 1400 RPM @ Idle Wooden (2 blade) prop = 1800 RPM @ Idle Is this something I should be worried about? I think you will have to measure the RPM at full throttle, with the wooden prop fitted . Paul D Quote Link to comment Share on other sites More sharing options...
ibbio Posted August 8, 2010 Share Posted August 8, 2010 curious for what reason is the prop change?? Quote Link to comment Share on other sites More sharing options...
macey2kk Posted August 8, 2010 Share Posted August 8, 2010 cant speak for the pap... but with a parajet, its definitely a reduction drive change when you go from a 2 blade to a 3 blade..or vice versa. Quote Link to comment Share on other sites More sharing options...
Farmer_Dave Posted August 9, 2010 Share Posted August 9, 2010 Hi duncan I replaced a 3 blader with a 2 (well I use both) without changing the reduction gear. The revs, at idle, picked up a bit with the 2 blade and up a bit at cruise and full throttle, but not over revving. Depends how steep the pitch is on your 2 blader as to wether you will need to change the gearing. If your reaching max recommended revs for your motor, that's how you'll get most thrust ,probably. Quote Link to comment Share on other sites More sharing options...
duncan_burdorf Posted August 10, 2010 Author Share Posted August 10, 2010 ibbio: The reason is cost! 2 blade wooden cost £210 & 3 blade carbon around £450! Thanks to Paul D and Flat Top Dave. I will follow your advice! If it does rev over the recommended 8000 RPM is there anything else I can do as in an ideal world I would like to be able to switch props without having to change components! Duncan Quote Link to comment Share on other sites More sharing options...
Farmer_Dave Posted August 10, 2010 Share Posted August 10, 2010 Hi Duncan I hope I'm wrong, but I guess you've had breakages ? I think you would have to change the redrive if your engine over revs. Or change your wooden 2 blade for one with a steeper pitch. The carbon ones have manufacturers numbers which reveal all the info on that set, so it's more likely you get exactly the right ones first time. Not sure if that's available on the cheaper wooden ones. Do you know your redrive ratio that you're currently running. This question's come up alot on the PPG biglist. I bet if you feed in a search with your engine make and size, redrive ratio and prop diameter, the answer would come up. I might try that for you if I have a minute. I might have to run for cover after this next comment, but, would you like to own a unit that doesn't smash propellers ? Back in a bit if I can find the answers you need Dave Quote Link to comment Share on other sites More sharing options...
duncan_burdorf Posted August 10, 2010 Author Share Posted August 10, 2010 Hi Dave, I've not smashed my prop! YET! • Reduction 3:1 The wooden prop is supplied by PAP, which is my motor, so am sure the pitch is OK! You've got my attention with a unit that does not smash props! ...... Quote Link to comment Share on other sites More sharing options...
Farmer_Dave Posted August 11, 2010 Share Posted August 11, 2010 Thats good Duncan. If PAP sold you the prop it should be good for their machine. If not atleast you'd be able to send it back. Is it a 125 cm prop or a 130 ? Quote Link to comment Share on other sites More sharing options...
duncan_burdorf Posted August 11, 2010 Author Share Posted August 11, 2010 It’s a 125cm prop which is sold as a PAP ROS 125 prop The prop is smaller than the standard 30cm 3 blade carb. prop so naturally the RPM are different. I haven’t checked my RPM at full throttle yet but will this evening! I'll let you know! Duncan Quote Link to comment Share on other sites More sharing options...
Farmer_Dave Posted August 11, 2010 Share Posted August 11, 2010 Good luck Duncan 130 with the right pitch would probably work but I reckon your 125 2 blader's gonna let it scream right up to 9000 rpm + so be carefull. Those extra 5 cms make alot of difference to economy too ! If I could fit a 135 to mine I would Dave Quote Link to comment Share on other sites More sharing options...
duncan_burdorf Posted August 11, 2010 Author Share Posted August 11, 2010 I'm off to the field in 30 mins so if will find out tonight! Quote Link to comment Share on other sites More sharing options...
fanman Posted August 11, 2010 Share Posted August 11, 2010 Ros125 - gearbox F200 - belt drive Don't these motors turn in different directions? Quote Link to comment Share on other sites More sharing options...
Farmer_Dave Posted August 11, 2010 Share Posted August 11, 2010 Sounds like someone might be sucking instead of blowing then. Well spotted sir!!!!! PAP might be embarrassed when that one comes back across the counter Quote Link to comment Share on other sites More sharing options...
duncan_burdorf Posted August 12, 2010 Author Share Posted August 12, 2010 Hi Guys, I checked against the standard carb. prop and its all kosher! I'm actually not sure if the prop is a PAP as it has PAP printed on the blades but has AEROBAT.es printed on the top of the prop! Either way its all kosher! I did rev my motor to max yesterday and only got as high as 7600 so well clear of the recommended 8000! Duncan Quote Link to comment Share on other sites More sharing options...
Farmer_Dave Posted August 12, 2010 Share Posted August 12, 2010 Nice one Duncan. 7600 rpm should be good. I'd be very interested to know if the revs at level cruising are any higher, if you can remember what they were before. Glad you're blowing and not sucking mate Did you get my email re. Simmo etc ? Dave Quote Link to comment Share on other sites More sharing options...
duncan_burdorf Posted August 12, 2010 Author Share Posted August 12, 2010 I PM'd you! Quote Link to comment Share on other sites More sharing options...
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