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Old Dec 05, 2012, 12:24 PM
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Originally Posted by Jacques.Eloff View Post
I agree that the ARC's are great quality motors - I have one in a Wemo and it pulls around 2KW on good packs, also using Hobbywing 100A ESC. My only concern in your case is that you will be adding a fair bit of weight to your model. The ARCs weigh around 60g more (each) than, say, a HET 2W-20. Then there is the Hobbywing 100A ESC's which are fairly heavy in themselves and you will require 10 or 12 AWG wire which will all add significant weight. I honestly don't have any twin 70mm experience, but those that do will tell you that a lighter setup for a model of your size will be more suitable. Twin configuration does bring about some interesting efficiencies over a single and you really don't require 3+KW in a model of this size. 2KW will be more than enough IMO and you could achieve that with a much lighter powerplant.

Jacques
Thanks Jacques, you are offering very good advice. What motors and controllers would you suggest? Making 2KW with this motor is very impressive. Where you using 6s? I will be very interested in seeing what numbers I come up with when I start bench testing. I think I would be lucky to generate even 1500 watts peak with the 5s packs that I have.
I am looking to make a total of 2800 watts with a greater than 1:1 thrust ratio to comfortably lift this 8lb jet off the grass. Ideally I would like to shed weight from the build and that is always good advice but there isn't much I can do about the esc's. I will need the heat-sinks this time and the Castle and Turnigy equivalents weigh the exact same when compared to the HW 100's. I choose the Hobbywings because of the reliability and quality and I think I can flush mount them quite easily. I had always intended on using Arc motors and I thought that was what I was getting when I purchased my motors from edfhobbies.com. They were falsely advertised and at the time I didn't know the difference. (They were actually marketed as Velocity motors manufactured by Arc on the website) The Arc motors I have now selected are each 45g lighter than the previous counterfeit Velocity motors I had installed prior. I am excited by this because I am also moving the two speed controllers forward to the CG location and I now can reduce some weight by removing the 4 capacitor packs and two runs of 12 awg for the battery leads that I previously had for my original controller locations. Even when I had the CC Ice Lites cooling in the exhaust ducts and having two 6s 2700 mAh lipos up front I had to still add 1.5oz of ballast to the nose to get the CG right and my auw was 8.5 lbs. I have since revamped my battery tray and canopy cover to allow the use of smaller 4s or 5s packs positioned further in the nose bay and this will hopefully eliminate the need for ballast weight. I would also like to look at the numbers when using 10 blade rotors on 4s. I would prefer thrust and sound effect over top end for this one. No seriously, I hope I am finally on the right track and I am taking all advice to mind. If it proves to still be too heavy in the end I will have look at again.
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Old Dec 05, 2012, 12:50 PM
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how about a twin 70mm setup like this Whalleyboy
eflight bl32 motors with cs 70/10 rotors cc lite 100's on a single 6s 5000 65c batt. the A10 weighs 7.5lbs and has well over 1to1 thrust to weight with flight times to 7mins. I think the only question is can you fit this batt in your F22? maybe have to use two 3s 5000's in series.

Nicks A10 (7 min 48 sec)
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Old Dec 05, 2012, 01:20 PM
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how about a twin 70mm setup like this Whalleyboy
eflight bl32 motors with cs 70/10 rotors cc lite 100's on a single 6s 5000 65c batt. the A10 weighs 7.5lbs and has well over 1to1 thrust to weight with flight times to 7mins. I think the only question is can you fit this batt in your F22? maybe have to use two 3s 5000's in series.

http://www.youtube.com/watch?v=a3L7D...kmMh8IQkxmD7XA
The BL-32 weighs in at 162g compared to the Arc 28-58-1 weighing in at 153g. Not too mention the kv is quite a bit lower and would force me to use 6s. A single 5000mAh 6s is too big too fit through the canopy hatch and two 3s 5000mAh with adaptors made would also weigh more than the current 5s setup. I don't think this package would benefit me or reduce the weight. But I like the idea! Keep em' coming.
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Old Dec 05, 2012, 01:46 PM
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Originally Posted by jcdfrd View Post
how about a twin 70mm setup like this Whalleyboy
eflight bl32 motors with cs 70/10 rotors cc lite 100's on a single 6s 5000 65c batt. the A10 weighs 7.5lbs and has well over 1to1 thrust to weight with flight times to 7mins. I think the only question is can you fit this batt in your F22? maybe have to use two 3s 5000's in series.

http://www.youtube.com/watch?v=a3L7D...kmMh8IQkxmD7XA
I would love to see my Raptor lift straight up into the sky with such vertical authority! I luv Nick's A10!!
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Old Dec 05, 2012, 02:09 PM
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Originally Posted by WhalleyB0Y View Post
I would love to see my Raptor lift straight up into the sky with such vertical authority! I luv Nick's A10!!
I love it too........ it is soo much fun to fly
the A10 has so much more drag than the F22 its not even funny I think you could go with 5s on the bl32 setup and still be ballistic and also the 6s 5000 is giving us 7min flight times so you could go down to 4400 or even 4000 possibly it is seriously over powered with out being over weight, we were going to throw my 5s 4400 TP batt in it but couldn't get cg without adding weight so it was not to be for now but we still may try it. lots of options though thats for sure, one thing I would be worried about is the kv on those arc motors is too high for the 10blade rotors, not saying they cant work but the bl32's are a proven setup drawing only 75amps on 6s 42k rpm I think the arcs are going to be way higher in amp draw and you could easily be seeing over 200amps with the twin arcs....not too many batts if any will be able to handle that
good luck though you are on the right track trying to keep things light
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Old Dec 05, 2012, 03:06 PM
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Hi John
So the combined power consumption of the twin BL32/CS70 combo is around 150A? I was surprised to see a 5000mah pack can last 7min...
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Old Dec 05, 2012, 03:17 PM
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Hi John
So the combined power consumption of the twin BL32/CS70 combo is around 150A? I was surprised to see a 5000mah pack can last 7min...
yes thats correct, its lasts because it is very over powered and most of the flight was 50% or less throttle. at 50% throttle it is fast!! at 100% throttle it is scary fast and you actually see the jet accelerating......it takes your breath.... I only use full throttle for adrenaline shots and vertical climb outs and it accelerates their too lol!!! its just crazy kick butt!
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Old Dec 05, 2012, 03:51 PM
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Hey guys, I'm just looking over the math here and i am wonderin if I looking at this right;

My 2950kv motor on a CS10 draws 90amps on 5s.

So maybe the Arc 3180kv on 4s would safe?

3180kv x 14.4 = 45792 rpm
2950kv x 18.9 = 58410 rpm
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Old Dec 05, 2012, 04:11 PM
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thats right for unloaded rpm but when you put the rotor on the rpms will drop 12-25% depending on the rotor used. for the 10 blade you will be looking at 36-37k rpm and 6-7lbs thrust for the twin setup........it will fly
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Old Dec 05, 2012, 10:45 PM
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hey Nerv I see you are in SJ you should come down and fly with us some time, we have a great field and group of guys

John
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Old Dec 06, 2012, 12:53 AM
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Quote:
Originally Posted by WhalleyB0Y View Post
Hey guys, I'm just looking over the math here and i am wonderin if I looking at this right;

My 2950kv motor on a CS10 draws 90amps on 5s.

So maybe the Arc 3180kv on 4s would safe?

3180kv x 14.4 = 45792 rpm
2950kv x 18.9 = 58410 rpm
The ARC should be fine on 4S in the CS-70, but bear in mind that the CS-70's all have skew adaptors, meaning you will need to get these separately from Extreme RC in Australia or Tamjets. The stock housing is also trash, so you will need to get an Eflite (or other suitable housing). I really don't think you should be setting yourself up for more hassles after your experiences. A Wemo or HET will be more efficient, but may not sound as good.

Jacques
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Old Dec 06, 2012, 01:36 PM
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Originally Posted by jcdfrd View Post
hey Nerv I see you are in SJ you should come down and fly with us some time, we have a great field and group of guys

John
Hi John, I heard about the nice field and EDF group from Manny and I really wanted to join the fun, but I'm struggling to get my landing skill dialed because I usually found myself spend 3 min in the air and 3 weeks fixing each retract mounts....haha. It would be really suck if I drive all the way to your field, have one flight, and embarrass myself with a crash landing. lol, but I'm not giving up, I need get consistent good landing in tomcats before I come down to your field. The runway in tomcats seems to be longer.
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Old Dec 06, 2012, 02:12 PM
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My landings with my foamie jets have mostly been pretty decent but I picked up a handful of these
( http://www.hobbyking.com/hobbyking/s...dProduct=28456 ) for the extra insurance on the Raptor landings. I will be adding one on my Funjet Ultra for the added stability on hand launches and low altitude high speed passes. Up until recently these 3-axis gyros weren't capable of handling dual channel aileron/elevator but these new version 2's will support it and it won't mess with my flaperons and mixing programs either. I used to just have a head-locking gyro on my F18 steering/ rudder channel but these new ones will take care of those sketchy take-offs down the runway too!
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Old Dec 06, 2012, 02:49 PM
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Originally Posted by nerv View Post
Hi John, I heard about the nice field and EDF group from Manny and I really wanted to join the fun, but I'm struggling to get my landing skill dialed because I usually found myself spend 3 min in the air and 3 weeks fixing each retract mounts....haha. It would be really suck if I drive all the way to your field, have one flight, and embarrass myself with a crash landing. lol, but I'm not giving up, I need get consistent good landing in tomcats before I come down to your field. The runway in tomcats seems to be longer.
the tomcats runway is mostly wider and only 50' longer but ya it does feel bigger. the invitation is there for you, we fly on sundays. one thing you wont have to worry about is any trees, ponds or obstructions...lol!! come join the fun plenty of us do embarrassing stuff....it seems to be part of the hobby
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Old Dec 17, 2012, 01:17 AM
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I started fabricating a new canopy with this one piece from a Banana Hobby F22 and some sheets of fiberglass.

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Robbed a hatch clasp from a scrapped F18

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