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Old Jan 29, 2013, 12:45 AM
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thanks Don, my prop is 8.5" diameter and in the video it has 12.55" pitch, so i will increase it and try it again and see if the same turns gets longer time.

yours looks very cool, i like the long spaced blades, what differences does that do for the prop?
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Old Jan 31, 2013, 08:57 AM
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i got a few more good flights at the indoor fling last night:
EZB in gym (8 min 47 sec)


i think my motor is a little too strong, and a thinner one will let me use more turns and less climb.
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Old Jan 31, 2013, 02:35 PM
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So these flights were done with a band about 1/16th thick and maybe 7 inches long. I have a variety of sizes coming today from .025 to .040. my question is, am i going to need to re-pitch my prop when i go to a thinner, longer motor with more turns?
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Old Jan 31, 2013, 04:40 PM
Editor - Flying Models
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Depends on the setup, but backing off the pitch a little is quite likely, especially with the change from 1/16 all the way back to .040. Given that you have some .025 coming, I would consider trying a double loop of that, and a bit longer, say 8-9 inches.
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Old Jan 31, 2013, 06:24 PM
Wonderfully Wicked
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Quote:
Originally Posted by derk View Post
So these flights were done with a band about 1/16th thick and maybe 7 inches long. I have a variety of sizes coming today from .025 to .040. my question is, am i going to need to re-pitch my prop when i go to a thinner, longer motor with more turns?
A 7" loop of .062 should take about 1100 turns so if you climb so much on only 600 turns you are overpowered. You need a longer thinner loop with more turns as the rpm is on the high side ~200 revs per minute. I would try a 10" loop of .040" which should weigh about 500mg which I believe is what your model weighed so 1: 1 rubber to weight is a starting point for this type of model. A 10" loop of .040 will take up to about 2000 turns but I would start at ~1200 turns and then ~1500 turns and see how it goes. You may need to get a yellow KP 10:1 winder from A2Z to make winding faster. Also .040 may still be too much, .035" may be better but you will need to flight test to fine tune the motor to your prop. You should be able to get 6-8 minute flights pretty easily as it is right now by playing with different rubber loops combinations and more time with a bigger higher pitched prop.
Don
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Old Jan 31, 2013, 06:41 PM
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ok thanks for the tips, seems i was a little off on what sizes i did order. i got .050, .040, and .030
so still a decent range for this type of plane, maybe a bit larger for the next one
as for the winder, i was thinking of opening it up and moving the pinion to the next gear out as it would increase the speed but will still count as the counter is on the output not the idler shaft. i will see if it still runs good that way and use it only for smaller rubber sizes. i just really like having a powered winder and counter in one. maybe i need to build a super charged brushless winder
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Old Feb 02, 2013, 01:56 AM
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so....the older motor i was using flew better than 10" loops of .030 and .040. on 900 turns the .030 just had enough power to float around for a few laps then sink to the floor. the new 10" loop of .040 flew fairly well but on 900 turns it flew 2:41 and still had lots of turns left over. then lastly i wound up the old motor i have been using in all the videos, 900 turns flew for 4:25 and was nearly all unwound at the floor.
so is the shorter motor just keeping the torque up all the way to the end? should i try the new .040 at a similar length as my old motor?
what type of break in do you guys do to your fresh rubber?
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Old Feb 02, 2013, 10:50 AM
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You are not putting enough winds in the 10 loop of .040. You are using less than half of the motors potential so that is why it is landing with turns. Your prop spins ~200 times per minute so if you put 900 turn in any rubber loop then you can not fly more than 900/200 = 4.5 minutes. So you need more turns which means a longer loop of the rubber you have now or a longer thinner loop so you can put in more turns and increase your time. Based on your models weight, I would stick with the .040 10" loop but put more turns into it. Try 1500 to1800 winds in that 10" loop and report back the results. How high did it climb on the 10" loop of .040 with 900 turns? My guess is not very high which is what I wold expect it to do since it was not wound up fully.
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Old Feb 02, 2013, 11:07 AM
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it went up to the ceiling on the 10" loop, and this ceiling is a higher than the hoop i hit in the video
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Old Feb 02, 2013, 12:05 PM
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Ok. It is climbing easily due to the low pitch. If you want more flight time you will need to add more turns. You can put in 1800 turns into that 10" loop of .040 then backoff say 100 or 200 turns to help reduce the climb, that way you fly more on the cruise portion of the rubber. If you don't want to put in more than 900 turns then you will have to lower your rpm to boost flight time, and you can do that by by increasing pitch or increasing diameter or a combination of both. Larger higher pitch props require shorter thicker motors than smaller low pitch props which fly best on long loops with many turns.
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Old Feb 02, 2013, 12:44 PM
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thanks for all the help Don, i am sure i can get it flying better, and if its still not good enough, i will apply all i have learned so far into the next model
the next one will be a full size EZB similar to yours and Kang's. i have most all the tools for building them now, just not the flying part i should really look at building a torque meter.
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Old Feb 02, 2013, 01:00 PM
Wonderfully Wicked
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A torque meter is very good to have and worth the effort of making one if you want to learn more on maximizing your flight times. Going from 13" to 18" span will not add too much weight on the wing and you are in the ballpark with your weights for a decent flying EZB. Years ago a good EZB was about 600-800mg and they still can put in good flight times. I did 28 minutes with a 600 mg EZB in a 115 foot high site and 30 minutes was done with a 800mg EZB at the Akron airdock.
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Old Feb 04, 2013, 02:41 PM
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Last night i started a pair of blades, about 3.5" long and 1.25 wide however, i couldn't get the pair below 125mg. Average thickness is .0085" thick and much thinner they would start losing fibers. Thinking of a total diameter of around 12 inches. The untapered spar was 63mg so it would be right at 200 after glue.
I will look through my sheets for any lighter wood for blades.
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Old Feb 26, 2013, 11:03 PM
Wonderfully Wicked
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Some videos of EZB test flying today. Both are EZB, one is unlimited (no weight limit) the other is 1.2 gram minimum weight (F1L).

260mg EZB (1 min 26 sec)



F1L 1.2 gram EZB (2 min 22 sec)
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Old Feb 27, 2013, 05:30 PM
more balsa please!
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Princeton, In
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Beautiful videos. Thanks for sharing.
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