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#136 | ||||||||||||||||||
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I'm here for the women..?
![]() Join Date: Sep 2006
Location: Calgary, Alberta
Age: 35
Posts: 57
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If Pletty said 14s was acceptable then go for it! I do know guys have pushed that motor to 6kW, and it can probably do more as long as its not getting hot. I have ran the Evo to 4kW and its a much smaller motor. I would try and keep as much diameter as possible on the prop, and reduce the pitch to keep your peak amps reasonable. With the higher voltage you will have lots of rpm, so you should be able to get away with less pitch than what someone running a 12s setup would have (12" usually). Probably a 22x12 would be a good start point...you are have about 35-40% more rpm than an Evo so based on that I would guess you will be in the 110-115A range on that prop with 14s. Then maybe try a 24x10 and see if you could run that, you might find you still have lots of available speed, but better pull out of it. Chad |
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#137 |
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Flyin' Around
![]() Join Date: Nov 2008
Posts: 29
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Chad,
Wow, that was really helpful, thanks! That is a good idea I think to try and maximize the prop diameter to keep the thrust up, I will take your advice. Pulling power is more important than speed (pitch) to the kind of flying I am doing. The only disadvantage I have noticed is that very large diamters seem to make hovering more difficult due to an increase in torque. Maybe it is just me but I seem to run out of ailerons trying to hold the prop torque in a hover on my 74" with full bevel to bevel throws, have you noticed this? I should also mention that with my EVO that my MAH per minute dropped a good 15% when I went from a 21" x 13" to a 22" x 12" which gave me a full extra minute of flight time. I thought it was just a glitch at first but 10 more flights have all shown the same improvement. The thrust is also better with the 22" and the WOT static amp draw is higher of course. Can you comment on how you feel that the 88" Yak would fly on 6000 + watts using either of the props you suggested? And do you feel that I am on the right track with using the Terminator or should I be looking at other motors for this plane? A few people seem to have good feedback using the Neu motor on this plane with 12S though the flight times seem to be really short (about 6 minutes) using 5000 MAH. Do you think that 7- 8 minutes would be possible with this plane without getting too heavy? I am getting 7-9 minutes ( batteries from 3850-5350 MAH) and leaving 30% in my batteries with my 74" and just wonder if there is a reason that this can't be done with the 88"? I have been reading these boards for a while and have come to respect your, so thanks again for the help with this project. James |
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#138 |
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Bad-ass Super Contributer!
![]() Join Date: Jan 2006
Location: St Peters Missouri
Age: 53
Posts: 891
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You know guys, I have watched where this thread has gone and I'm really surprised. I have run the Hacker A60-18L, Spin99, with Flightpower 12s 4900 25c batteries for two years and over 450 flights without a single thermal event. I fly aggresive 3D all the time and have beat this package unmercifully. I don't pull 20 second long uplines but I do put her right on the deck. You might want to rethink your setup or flying styles to fit the advantages of the light weight.
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Mark Trent Team Futaba Team Flight Power Krill Aircraft Skyline Aviation Hacker Brushless Fromeco |
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#139 | ||||||||||||||||||
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You Know How I Roll!!
![]() Join Date: Jan 2007
Location: NorCal
Age: 37
Posts: 163
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I was really suprised also after reading this thread a few days ago. I too have been running this same setup in my 3DHobbyshop 89" Slick with a APC 25x12.5 E prop. I have had zero issues and it has plenty of power at 18.5lbs AUW. 4000 watts = 216 watts per pound and 5.3 hp........
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#140 |
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Gettin' Lower!
![]() Join Date: Jun 2007
Location: Fairfield, CA, USA
Posts: 73
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Mark,
The lightest the plane gets is about 18lbs even ... with going to more carbon. I thought the issue was mine alone, but I have two identical setups....that I followed here...and these planes thermal out...no doubt. I have seen it in both of mine, plus Matt Stingers Plane. Maybe there are variations in these speed controls. Below are photos from Bakersfield IMAC Free Style. Matt Stringer is a fantastic pilot...but these are photos of his plane thermaling out...and getting him last place...one minute into the event. Bottom right is an ugly dead-stick. He did a bit of damage. The issues are not isolated or rare. I have moved my ESC down to the bottom box for cooling. However, I have had this plane previously thermal on me probably 8 times...and I don't trust it anymore at all. I have cleared it for use by my 10 year old to fly it for IMAC sequences...but low 3D is banned with the config. The ESC needs to be higher amp draw...down in cowl box. Its not an airframe issue, but clearly the components are being used by us too hard...too close to the edge. Just our experience out here in the west. If I was buying new for this plane, there no way in hell I would use that ESC. The motor is marginal on power...as has been discussed at great length in a build forum for the Electric AJ Slick 89" at RC Groups. In fact, of all the motor options...it just about the least powerful. I want people to understand this up front if they are throwing down their hard earned cash. - Richard Carlton Last edited by Captain Carlton; 11-10-2009 at 02:41 AM. |
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#141 |
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Flyin' Around
![]() Join Date: Nov 2008
Posts: 29
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Mark,
You mentioned the use of carbon to get the plane down to 18 lbs. I am assuming that you are changing out the main gear but is there anything else? I would like to suggest one easy way to save perhaps 2 ounces on at least some EF planes. The hinges really long, in fact about 2/3 of the barbed end sticks inside the wing and is usually also coated with a lot of epoxy or polyurathene glue adding even more weight. I have been cutting my hinges so that they just protrude through the back of the wood. I also sand the hinges to roughen the surface then acetone for a better bond. I own two of the Hacker 99's that I use in my 74" Yaks and they have been flawless. It really does however sound like they are just not enough for your particular setup. It is interesing that Mike has not had any problems with his setup after 450 flights but maybe the temps in your area are just a little warmer and his setup is on the edge but has not gone over it yet. Certainly I want to have a good reliable setup and I like having good power for the pull out. Weight wise I don't think that the 14S will come in that heavy. If I were to run TP Prolites, the batteries would weigh 1,684 grams (2-5S at 602 grams, 1 -4-S at 480 grams) versus 1,432 grams for the 12S setup in Prolites. If I ran Zippy 5000 MAH packs in 12S the weight would be 836 grams x 2 = 1,672 grams or a whopping 7 grams lighter than a 14S setup in the Pro Lites. The prop will be a little lighter since it will be smaller too. (grin) I really don't think that the 14S setup has to be heavy at all and with throttle management should give 15% longer flight times. Realistically I don't think that I can even feel a 5% increase in the weight of a plane and that would be almost a pound in this case. How much does a smoke system weigh or pipes? If anyone has an opinion on the best flying weight for the 88" Yak please let me know while i am in the design phase of this project! Thanks, James |
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#142 |
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Flyin' Around
![]() Join Date: Nov 2008
Posts: 29
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Richard, Wow, that is a big electric setup. Can you hover this plane? How are your flight times? And I notice that you either run 5000 MAH or 10,000 MAH? Would that be a doubling of your battery weight? Thanks, James
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#143 |
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Flyin' Around
![]() Join Date: Nov 2008
Posts: 29
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Jagerbomb, So if you are getting 4,000 watts then you are drawing close to 90 amps WOT? Hmm, that should be 10% below the max on the ESC. Really glad to hear that this setup is working for you. James
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#144 |
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Flyin' Around
![]() Join Date: Nov 2008
Posts: 29
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Mark, That is a great shot of your 88" hovering, nice! How are your flight times with the 4900 12S? I am trying to keep an open mind here on which way I should go. Using Prolites, my proposed 14S setup would come in 252 grams heavier than a 12S 5000 MAH 12S setup so not that much of a difference. I was looking at the Zippy batteries because of price and they are a lot heavier, in fact the ProLite 14S setup would be virtually the same weight as a Zippy 12S setup. If you are happy with 4000 watts, then 6000+ ought to be a lot of fun I am thinking. (grin) Thanks for the input. James
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#145 | ||||||||||||||||||
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Bad-ass Super Contributer!
![]() Join Date: Jan 2006
Location: St Peters Missouri
Age: 53
Posts: 891
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Are you sure it is a thermal event? What temp is the esc showing? Could it be your batteries? I ask alot of questions because I've seen a similar circumstance that turned out to be the batteries were going open. I've flown in over 104 degrees with this setup and like I said before, no issues. Also what is your air routing over the ESC? I'm waiting on a AJ Slick and will transfer my power setup to that plane, I talked to Andrew at length about it and he really likes his setup with the Slick which is the A60-18L. |
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#146 |
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Gettin' Lower!
![]() Join Date: Jun 2007
Location: Fairfield, CA, USA
Posts: 73
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Mark,
The ESC was running over 200 degrees, and cutting off. We plugged in the Spin box device...and it gave us this info. The Batteries are TP 6S-5000s..Pro Power 30s. The ESC were mounted on the side of the motor box...as shown in this thread...and there wasn't a lot of flow. Ambient temperatures at the time was 75 degrees to 105 degrees. There must be some variations in MFG of this ESC for there to be this big of a different in performance. We are using 6S-5000 in series for 12S-5000 for freestyle...and 12S-8700 (four TP 6S-4300 Prolite V2) for IMAC. 12S-5000 just won't be long enough for two sequences....unless you fly a really compressed box. Earlier this year... we ended up dead sticking down to the runway after we flew out of the box on the 2nd sequence. Very demoralizing for my son Alex. In terms of overall power, if we're at 70% power for a hover (no joke) ...its not much of an energy reserve...if you get in trouble...you can kiss your butt good bye. I have talked to Andrew and Ben Fisher at length. Ben prefers the Plettenburg setup by far. I assume that Andrew uses the AJ Slicks for fun and entertainment. He didn't fly his own design (Gas or electric at TAS)...so make what you will of that. Andrew is a great guy ... but I have a personal rule about people eating their own dog food. I have two of the AJ Slick 89's...and for me...they came out a bit heavier than the 88 Yak. My 88 Yak with 12S-5000 was 18.0 lbs with no wheel pants, and CF LG. The Slick with the same config came out at 19 lbs. All I can say for sure is that we have two groups of people with very different experience with the Hacker gear. I would have greatly preferred to have had your experience...but it didn't turn out that way. - RC |
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#147 | ||||||||||||||||||
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Flyin' Around
![]() Join Date: Nov 2008
Posts: 29
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The first motor I had in my 74" Yak was a Hacker A60 24S. Turning a 20" x 10" APC put the amps right at max for the motor and I was also at about 70% power to hover with that setup which I also felt was too weak. The motor also ran hotter than my Eflite Power 160 or the Pletty, despite the latter making a lot more power. I know of one person that burnt one of these up in this same plane so I tried to be careful to not repeat that. I mounted the Masterspin 99 Opto on the bottom of the motor box thinking that the airflow might be the best there due to the bottom of the cowl being open there. I just got a spin box so will check actual temps but from just touching the ESC after a long flight I can tell you that mine comes down just warm, never hot. My Eflite setup was pulling 90 AMPS WOT on the 20" x 10" APC. Switching to a Xoar prop dropped that to 81 AMPS. The Pletty is turning a 22" x 12", makes more power but draws less than the Eflite, about 79 AMPS. I am very curious about how your Yak flew with the 8700 mah setup, did it feel excessively heavy to you? Was it really noticeable? Thanks, James |
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#148 | ||||||||||||||||||
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Bad-ass Super Contributer!
![]() Join Date: Jan 2006
Location: St Peters Missouri
Age: 53
Posts: 891
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#149 |
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Gettin' Lower!
![]() Join Date: Jun 2007
Location: Fairfield, CA, USA
Posts: 73
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Ok, well I have solved the ESC cooling issue. Its still a a bit gutless...but now the ESC cooling is fixed. Photos attached...
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#150 |
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You Know How I Roll!!
![]() Join Date: Jan 2007
Location: NorCal
Age: 37
Posts: 163
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Captain,
Have you tried the APC 25x12.5E prop on this setup? If not I believe this is your power problem with this setup. Many have tried this setup with Zoars and other wooden props. But non of them perform like the APC E props. 24x12E is another APC prop others have tried and liked on the 18L. I hover my 18.5lb Slick at 1/2 throttle and it has plenty of pull out with the 25x12.5E. Its not foamy rocket power but it is plenty. Give it a try I bet you will be surprised...... Chris |
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