john melia 1 Posted May 25, 2013 Share Posted May 25, 2013 hi guys , i've converted my dolphin edf jet into a pusher , i contacted hobbyking asking their advice on motor size and prop , and they give me this info Rpm/V: 2200kv Shaft: 3.17mm Voltage: 2S~3S (7.4v to 11.1v) Weight: 50g Watts: 342w Max Current: 34A ESC: 40A Suggested Prop: 7x4(2S) ~ 5x5 (3S) so this is exactly what i got , but yes theres a but , i took it out and on hand launching at full power there didn't seem to be enough of something , to keep it airborne , hence it dived for the ground twice , with the second occasion terminating my trials forthwith . the prop is 5x5 as the 7x4 wouldn't fit because of the clearance from pod to fusalage . has anyone got any ideas ? Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 25, 2013 Author Share Posted May 25, 2013 sorry put two of the same photos on Quote Link to comment Share on other sites More sharing options...
WolstonFlyer Posted May 25, 2013 Share Posted May 25, 2013 Is that prop on the right way? It looks backwards to me.Looking from the back of the plane forwards the motor should turn clockwise and the swept tips of the prop should trail the direction of rotation. Any numbers on the prop should face the front of the plane. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted May 25, 2013 Share Posted May 25, 2013 Have you measured the watts and the rpm, on the new set up. I guess you are well aware that bigger props mean better performance, for the same revs etc. Can you not stick a 3s battery in, whilst you are at it. I personally like volts! What were the watts it used to fly on? Quote Link to comment Share on other sites More sharing options...
WolstonFlyer Posted May 25, 2013 Share Posted May 25, 2013 Just had a look at my pusher (AXN clouds fly from HobbyKing) and it does look like your prop is on the wrong way. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted May 25, 2013 Share Posted May 25, 2013 John, we need to know the weight of the model to comment really. Its possible you just don't have enough power. Do you have a watt metter? If so how many watts are you getting? The second possibility is that thrust angle of the motor isn't right. Being a top (pod mounted) pusher it might be that thrust line is out with respect to wing's centre of lift. A third possibility is that you may have shifted the CoG relative to where it should be. Without more inforimation its difficult to say. BEB Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted May 25, 2013 Share Posted May 25, 2013 Hi , Know the motor well its best with a 6x4 and on a Good 3s battery will give 200 watts , so would be good for a model up tp 2 lbs in total weight . Quote Link to comment Share on other sites More sharing options...
crispin church Posted May 25, 2013 Share Posted May 25, 2013 like all of the above agree prop on wrong way and is it a pusher prop is it going right way wind towards the rear when prop going anticlock wise cog and biggest battery you can fit in and would go for biggest motor that would fit in the pod or even better cut nose off and put the motor wear it should be on the nose what ever you do cog afterwards not trust makers put numbers in a cog calc Quote Link to comment Share on other sites More sharing options...
GrahamC Posted May 25, 2013 Share Posted May 25, 2013 Another vote for looks like you have the prop on round the wrong way. Remember that the front of the prop needs to be towards the front of the plane. If you need to reverse the motor direction swap over two of the three motor leads. Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 25, 2013 Author Share Posted May 25, 2013 oh dear me , where would i be without you guys ? i'm so glad i put this thread in the beginners section because that just shows what i am ........... a beginner , but i must say i enjoy the failures as much as the successes , simply because i tend to learn more from my failures . And yes it was on the wrong way i've turned it round , but i can't do anymore testing just yet until the glue dries thanks everyone yet again Quote Link to comment Share on other sites More sharing options...
GrahamC Posted May 25, 2013 Share Posted May 25, 2013 It will make a LOT of difference. I think you will find that you have plenty of power now. Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 25, 2013 Author Share Posted May 25, 2013 Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 26, 2013 Author Share Posted May 26, 2013 well took the dolphin out today , and what a difference putting a prop on the right way round makes it flew fantastic , much better than the edf unit , i've just measured from the motor shaft to the top of the fuselage , and i can just get a 6x4 on , so i've ordered a couple to try out , i think it would climb and perform much faster with the 6x4 ?? Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 26, 2013 Author Share Posted May 26, 2013 forgot to mention , while i was out flying today , i noticed two other guys further down ther field from me flying model aircraft , so i packed my gear up and drove round to the other side of the field to meet them , two very nice sociable guys , so all in all a great day , and two new friends to boot , can't be bad Quote Link to comment Share on other sites More sharing options...
WolstonFlyer Posted May 26, 2013 Share Posted May 26, 2013 Cool, I am glad it is sorted out. I use a 6x4 on my AXN pusher and that is a 2200Kv motor and the performance is amazing. Just make sure you don't go over the current rating of your motor or ESC. Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 26, 2013 Author Share Posted May 26, 2013 thanks wolstonflyer i'll put the watt meter on it and make sure Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted May 26, 2013 Share Posted May 26, 2013 well done from me john.......i've done the same with a prop also......the easy way is to remember to have the writing at the front...... ken anderson ne..1 ....writing at the front dept.... Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 26, 2013 Author Share Posted May 26, 2013 thanks ken Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted May 26, 2013 Share Posted May 26, 2013 Hi John, the new guys must have been on 2.4G I assume. Cheers Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted May 27, 2013 Author Share Posted May 27, 2013 yes all on 2.4 Quote Link to comment Share on other sites More sharing options...
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