avalore Posted August 20, 2020 Share Posted August 20, 2020 Whatever you think of the guy, try Brad Quinn at Paramotor Training UK (https://paramotor-ltd.business.site/) for propellors. I didn't train with him but recently needed a new prop and went to him, mainly because of speed and price. He's had his own props made. They're very well priced. They're a touch heavier than the equivalent Helix but only marginally so. I've not noticed any difference in thrust (apart from maybe the curve is slightly different - more in the mid range and a bit less at top rpm, but that's maybe because I went from a 130 to a 125). Very impressed with the product, price and speed. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 20, 2020 Share Posted August 20, 2020 8 hours ago, MatthewClay said: Can you substitute anything on here or do you have to get the exact same thing? I'm no expert so take this for what it is: No, you need to get a "matching" propeller.... Not "exact". If the pitch and diameter are the same, you are likely to be within +- 200rpm of the originals top end. I say this because I lost 200rpm with my KD propeller but I am still getting aprox 2.2 liter per hour burn. In principle, the loss in rpm would be a loss in static thrust but a gain in cruse efficiency but its nothing I can detect on my machine. The manufacturer ought to be able to provide you with a "matching" propeller given the Re-Drive ratio and motor output, that way any error would be on them but if anyone else has a formula / rule of thumb / expertise on the issue, please throw some light on it Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 22, 2020 Author Share Posted August 22, 2020 Can anyone explain that last post I posted? Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 22, 2020 Author Share Posted August 22, 2020 (edited) DT propeller wants to know the reduction? I have no idea what this means and am having a terrible time finding what I need I’m about to just copy my broken one and make one myself. Edited August 22, 2020 by MatthewClay Quote Link to comment Share on other sites More sharing options...
alan_k Posted August 23, 2020 Share Posted August 23, 2020 Hi Mathew, you quoted simonini mini plus 2, 130 cm pign 55. The engine is a Simonini mini plus 2 which has a reduction ratio of 2.42 or 2.62 (info taken from propeller supplier) The reduction is a ratio between the small and large pulley that the belt is on. Measure the diameter of both pulleys and the ratio should be either 2.42 or 2.62 (you will probably be slightly out with the calc as I think the exact ratio is taken from the bottom of the pulley grooves, but you should be able to identify which is yours). 130cm is the diameter of the prop, I think the 55 is the diameter that the prop mounting holes are on in mm. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 23, 2020 Share Posted August 23, 2020 7 hours ago, MatthewClay said: Can anyone explain that last post I posted? "130" is very likely to be a reference to diameter as in 130cm. The other info seems abstract or propriety lingo....? Helix are the only manufacturer in have used that print easily decipherable language on their propellers. 7 hours ago, MatthewClay said: DT propeller wants to know the reduction? Measure the diameters of the pullies and divide the larger by the smaller (200mm divided by 50mm = 4 to 1 ratio or 4-1) If it had gears you would divide the tooth count) Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 23, 2020 Share Posted August 23, 2020 7 minutes ago, alan_k said: I think the 55 is the diameter That might be a winner and is easy to check Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 23, 2020 Share Posted August 23, 2020 7 hours ago, MatthewClay said: I’m about to just copy my broken one and make one myself. I know the feeling... Its a lot of work though, it would almost be quicker to build a simple copy machine than carve by hand! Quote Link to comment Share on other sites More sharing options...
Pete S Posted August 23, 2020 Share Posted August 23, 2020 (edited) I think that as posted 130 is the prop diameter but pign is the pinion size (diameter of the small pulley). I found this link which may help you, or someone else here to nail down exactly what you need. https://www.southwestairsports.com/ppgtechinfo/simonini/simonini_mini2_plus/service_manuals/MINI2PLUSENGLISH.pdf Extract: REDUCTION RATIO AVAIABLE 1:226 Crown gear 129 mm / Pinion 57mm 1:230 Crown gear 129 mm / Pinion 56 mm 1:234 Crown gear 129 mm / Pinion 55 mm 1:242 Crown gear 129 mm / Pinion 53 mm 1:3 Crown gear 138 mm / Pinion 44 mm From the information it looks like the reduction is 1:234. Always ready to be corrected of course. Edited August 24, 2020 by Pete S list of ratios formatting was confusing 1 Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 23, 2020 Author Share Posted August 23, 2020 This is what is on dt propeller. They seem inexpensive $140.00 US dollars shipped but I don’t know which one. Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 23, 2020 Author Share Posted August 23, 2020 7 hours ago, alan_k said: Hi Mathew, you quoted simonini mini plus 2, 130 cm pign 55. The engine is a Simonini mini plus 2 which has a reduction ratio of 2.42 or 2.62 (info taken from propeller supplier) The reduction is a ratio between the small and large pulley that the belt is on. Measure the diameter of both pulleys and the ratio should be either 2.42 or 2.62 (you will probably be slightly out with the calc as I think the exact ratio is taken from the bottom of the pulley grooves, but you should be able to identify which is yours). 130cm is the diameter of the prop, I think the 55 is the diameter that the prop mounting holes are on in mm. Is the 2.42 or 2.62 in cm, inches? Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 23, 2020 Share Posted August 23, 2020 1 minute ago, MatthewClay said: Is the 2.42 or 2.62 in cm, inches? No that's the reduction. Eight one down "Mini2" 1 to "2.42" reduction. So if what Pete S says is correct, you are good to go but double check Make sure you have the "Mini2" or confirm the hole pattern (mounting bolt pattern) Quote Link to comment Share on other sites More sharing options...
Pete S Posted August 23, 2020 Share Posted August 23, 2020 Just to expand what Mark said, the 2.42 is the ratio between the diameter of the large pulley to the diameter of the small pulley so it does not have units. It means that the engine will rotate 2.42 times to get the prop to rotate once, hence reduction. Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 23, 2020 Author Share Posted August 23, 2020 Thanks for all the help, I will do some measure if and math today to double check some things. This is all very confusing, but I’m starting to get a grasp I believe. thanks again Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 23, 2020 Share Posted August 23, 2020 Splendid Don't flap if you are getting a bit lost Matthew... keep chipping away until it makes sense to you.I and I suspect Pete S or anyone else will be cautious of saying "Buy this one" because errors are easy to make and we don't want to carry that weight 1 Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 23, 2020 Author Share Posted August 23, 2020 The big gear is 5 1/8 inches or 130.175 mm by 2 1/8 inches or 53.975. If I divide those 2 like said above it comes to 2.41176. So I’m guessing I have a ratio of the 2.42? Is this making sense? Quote Link to comment Share on other sites More sharing options...
kiwi k Posted August 23, 2020 Share Posted August 23, 2020 all i will add is if you had the aluminium gussets welded into the lower frame rails chances are you have strengthened that area , but you will of forced the damage or bending to another area the frames are designed how they are for a reason and mainly to bend or break so as not to hurt the pilot , i know you think your improving your destruction rate but you could be making it to rigid and not helping yourself. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 23, 2020 Share Posted August 23, 2020 9 minutes ago, MatthewClay said: So I’m guessing I have a ratio of the 2.42? Is this making sense? Sounds good to me. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 23, 2020 Share Posted August 23, 2020 6 minutes ago, kiwi k said: i know you think your improving your destruction rate but you could be making it to rigid and not helping yourself. These are things well worth considering.... I think, from what I can see, there is now less chance of one of those base tubes departing and puncturing a kidney Quote Link to comment Share on other sites More sharing options...
Pete S Posted August 24, 2020 Share Posted August 24, 2020 MathewClay, check your pm. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 25, 2020 Share Posted August 25, 2020 On 19/08/2020 at 02:39, MatthewClay said: 2-when your taking off what’s the thought process? I was thinking about this when I launched yesterday: It was 6mph+ on the surface gusting to maybe 12mph.... cold air and cumulus... I wasn't super confident they where good conditions for a nice chilled flight. (it was pretty turbulent all the way to cloud base // not much fun) I chose to set up and warm the motor... knocked the motor off to ground handle (to ascertain I could handle the gusts) When you ground handle with the motor off, you have less to think about which makes a massive difference in your ability to process what is occurring. Don't let it overshoot // don't let it drop back // Keep it straight // Your mind is doing circuits around a few items in quick succession... in this mode, you are missing throttle control the run and all the launch concerns/stress. Furthermore, without the motor running, there is less jeopardy so you are more relaxed. Very often, you will reach a point in this process where you will think "Shit, if the motor was running I would simply hit the throttle, run and launch"..... Easy.... I think it is too easy to focus on the launch... we obsess over getting airborne. Strictly cut your process into two... (everything before hitting the throttle and everything after) You want to GROUND HANDLE until that moment comes where IF the motor was running, you would easily launch only this time, the motor IS running "I'm going flying"..... No your not, your are going ground handling with the motor running and you MIGHT hit the throttle Quote Link to comment Share on other sites More sharing options...
AndyB Posted August 25, 2020 Share Posted August 25, 2020 When you ground handle without the motor, you get the wing up, then taxi it....pushing forwards to keep it up. When you fly, you do exactly the same. You get the wing up, taxi it a bit until happy, then launch. Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 26, 2020 Author Share Posted August 26, 2020 That’s a really good way of thinking about all this. Quote Link to comment Share on other sites More sharing options...
MatthewClay Posted August 27, 2020 Author Share Posted August 27, 2020 This is the last prop I bought. Still trying to figure out which one to order. Quote Link to comment Share on other sites More sharing options...
Blackburn Mark Posted August 27, 2020 Share Posted August 27, 2020 H = Helix 30= 30kw(max power) F= fixed pitch (as apposed to adjustable) 1.3 = diameter L= Left hand rotation (counter clockwise) M = profile shape (wing shape) 05= pitch (5 degrees) 2= blade count Set 8 is in reference to the mold it came out of I think Quote Link to comment Share on other sites More sharing options...
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