|Mar 23, 2007, 03:29 PM|
Scorpion 30mm Motors will be here Next Week!
Funny you should ask! I spoke with the owner of Scorpion last night, and the stators for the 30mm motors are in, and the motors are in production as we speak. Scorpion is doing a short production run over the weekend to get me some motors for the upcoming RCX show in Pomona, California next weekend on the 31st of March and 1st of April.
Scroll back up a few posts to Post #11, and you will see an announcement that I made yesterday with all the details.
We might offer a few combo deals in the future, I will look into that.
|Mar 24, 2007, 12:48 AM|
what do you have that fits my needs..
I need an out runner that can spin a 5.5x4.5 or 6x4 apc at around 22 to 25000 rpm on a 4s battery
Around 400 to 450 watts should do it this is on a 19 oz (without batteries) wing..
Looking for the sweet spot on a 36inch ritewing demon.. And the out runers keep the prop away from the TE so the noise does down to a level that the school naboughs do not frown on..
|Mar 24, 2007, 02:27 AM|
Let's start out with a little math to calculate what you need. You say you are going to run 4 cells and want 22,000 to 25,000 RPM on 4 to 4.5 inches of pitch with 400-450 watts. So it looks like what you are interested in around 90-95 MPH of pitch speed. If you figure 14.0 volts on a 4-cell pack, with your prop, you are looking at an operational Kv of 1600-1800, which would equate to a no-load Kv of 2000-2250.
Unfortunately, you are not going to find many 400 watt outrunners with this kind of Kv, so a few concessions are going to have to be made. You also said that you are interested in keeping the noise down, and the best way to do this is to run a bigger prop at a lower speed. To get your desired 95 MPH pitch speed, you can run 4" of pitch at 25,000 RPM, 5" of pitch at 20,000 RPM, 6" of pitch at 16,667 RPM, 7" of pitch at 14,285 RPM or 8" of pitch at 12,500 RPM. All of these combinations yield a pitch speed of 100,000/1056 or 94.7 MPH.
To get the power requirements that you desire, I would recommend the Scorpion 3014-16 motor It has a Kv of 1190, weighs 4.12 ounces, and is good for up to a max of 600 watts, so at 450 watts, it would run very efficiently. On 4 cell operation, you are going to need to pull 32 amps to get 450 watts of power, so make sure that your battery pack is up to the task.
With 32 amps of current on 14.0 volts, you can expect the 3014-16 motor to turn right at around 15,000 RPM, with an efficiency of 84-85%. At that RPM you will need to run about 6-1/2 to 7" of pitch Looking at the APC offerings, it looks like your options would be a 7x6 or a 7x7 Sport prop. You can expect around 35-36 ounces of thrust from either of these 2 props.
So there you have it. Running a 7x6 prop at 15,000 RPM will get you a pitch speed of about 85 MPH and pull about 400 watts. The 7x7 will get you around 95 MPH and pull about 450 watts. Plus, the bigger prop turning slower will make the neighbors a lot happier!
Once I get the motors in next week, and get a chance to play around with them a little bit, I will have some actual numbers to give you, but for now, these are pretty close.
Hopefully that helps!
|Mar 24, 2007, 02:41 AM|
I apreciate you taking the time to work the numbers..
The only problem with that size prop is torquing of the wing one of the resons we have been running the smaller props is to keep the wing from pulling over when transitioning to WOT
May not be the most efficient way to get the job done but it is flyable like that..
So if we toss the watts out the window as a limmiting factor im sure that will open things up a bit.. as to a selection..
Ya i have been looking for the just undewr just over 100 mph seems to be a good speed for a 36 inch wing as far as keeping track of it in the air..
The noise i was speaking of is the noise created when a prop is spun close to the TE line when a inrunner is used.. prop may be no more that about 1./2 and inch from the TE so with the out runner hanging it out the back hets the prop about 2 or more inches away from the TE and the noise goes way down.
I have flow this wing with up to 600 watts of power and around 32000 rpm but it become way to small too fast..
I had been running a komodo 283 at aroung 450 to 500 watts around 35 or 37 amps and they are melting around the 3rd or 4th time out.. So may be time to get a pupose built motor..
again just looking for that majic bullet for the wing..
thanks again.. and i will keep checking back after you get the 30's in..
|Mar 24, 2007, 02:53 AM|
I Almost Forgot!
When I gave you the numbers above, I was not even thinking about the Next series of Scorpion motors that are coming just around the corner. Scorpion is coming out with a whole series of High Kv motors in the 22mm size very shortly for helicopter and ducted fan applications. These motors are all in the 2500-3500 Kv range. The new 2221 motor is available in a -8, -10 and -12 model with Kv of 3600, 3000 and 2600 respectively. These motors are good for over 300 watts of power, and only weigh about 2.5 ounces. This may be just what you are looking for to run with the small props.
I will be getting some samples of these next month some time, and they should prove to be pretty interesting. I will let you know when they come in.
|Mar 24, 2007, 08:31 PM|
I think the 36" demon really needs about 400-500W of power to provide both good thrust and speed. I think with a 22mm motor Paul you will run into the same problems we have had with the 25mm komodo motors.
I'm thinking when the 30mm DIY motors come out from Scorpion then I think you can really put a motor together which will hit the spot.
Lucien - When are your 30mm DIY motors due out??? l
|Mar 24, 2007, 09:53 PM|
The approximate glow equivenents for the Scorpion 30mm line is as follows:
Scorpion 3008, 400 watt max = .12 to .15 Glow Motor
Scorpion 3014, 600 watt max = .20 to .25 Glow Motor
Scorpion 3020, 800 watt max = .35 to .40 Glow Motor
Scorpion 3026, 1000 watts max = .45 to .50 Glow Motor
Scorpion 3032, 1200 watts max = .60 to .61 Glow Motor
I am running an early prototype of the 3020-14 motor in my 150% F-4 Phantom ParkJet that weighs 4 pounds 5.5 ounces ready to fly. I am running a 6-cell A123 pack at 35 amps into an APC 9x7 Sport prop which gives me 602 watts of input power. The plane flys with good authority, and has a top speed in the 70-80 MPH range. For a video of how this plane performs, please check out my F-4 Phantom Maiden Flight Video.
fly_boy99 and jfinch,
Scorpion is producing the 30mm motors right now, with the first batch shipping out on Monday. They are making extra parts with this production run, so as soon as the motors are finished in a couple weeks, they will be bagging up the extra parts to sell as kits. I am hoping to have kits available in time for the Toledo show in the middle of April. If they get done earlier, I will definately let you all know!
|Mar 25, 2007, 12:28 AM|
Lucien I really love the two motors that ID makes do you think in the near future that the 25 amp esc will run four servos if so you will be a one stop shop.
|Mar 25, 2007, 03:05 AM|
First, just to clarify one point, Innov8tive Designs does not make the motors and ESC's, Scorpion does. We are the US distributor for the product line. We have a very close relationship with Scorpion, but they are the ones that are making the products.
We have been working the past week with Scorpion on the 25 Amp ESC to get the BEC to be able to handle 4 servos, and I am happy to say that the problem has been solved! After looking very closely at BEC circuit on the ESC, Scorpion has changed the voltage regulators that were being used to a different model that can handle more current, and dissipate the heat better.
Most servos draw only 5-10 ma of current when they are sitting at rest. However, when they start moving, the motor in the servo starts pulling a lot more current. This current can be anywhere from 100ma up to as much as 500ma or more depending on the size of the motor in the servo. For the foamie type planes that are using the 25 Amp ESC, the servos being used are in the 5-15 gram range for the most part, and servos of this size draw around 150-200 ma of current while moving. This means that if you are in a hover with a 3D plane with all 4 servos running back and forth at the same time, the worse case current draw would be about 750-800ma. In any other flight condition, you would only be drawing 200-300 ma of current.
I just checked a GWS Naro servo and ran it back and forth continuously and it pulled around 150-200ma of current, and when I grabbed the servo arm and stalled it, the Naro servo drew around 0.65 amps at full stall. This confirmed my statement that 4 servos running continuously would draw 750-800 ma of current.
With the earlier 25 Amp ESC, when running on a 3-cell battery pack, only 3 servos could be used without overheating the voltage regulators on the ESC. I tested the earlier 25 amp ESC's by running them on a brushless motor, and plugged a Johnson 250 motor to the output of the BEC circuit to simulate the motors in the servos continuously running. On 3 cells, a J-250 motor will draw around 550 ma of current. This simulates 2 medium or 3 mini servos running continuously. On the earlier 25 Amp ESC's, the ESC would run with one of the J-250 motors atached and run the motor at the same time. If I added a second J-250 motor to the BEC, this brought the BEC current up to 1.1 amps and the voltage regulators would overheat and go into thermal shutdown within 10 seconds.
I just finished testing one of the upgraded 25 Amp ESC's with the new voltage regulators and they are performing very well. I ran the ESC at 10.5 volts to simulate the 3-cell Li-Po battery under load and ran a Scorpion 2215-22 motor with an 11x7 prop to really load down the controller. At this condition, the motor draws around 160 watts of power. I ran the motor like this for about 2 minutes at WOT and the controller barely got warm.
Next, I plugged in one J-250 motor to draw 550ma of current through the BEC circuit, while leaving the motor at full throttle. I let it go for another 2 minutes and the ESC did not miss a beat. So far so good.
Finally I plugged in the second J-250 motor and the BEC current was now at 1.1 Amps, with the motor still running at full throttle. I let it go for 2 more minutes and it kept right on running. This is the equivilent of 5 mini servos running continuously while the motor was running at WOT, and it never missed a beat!
After that I reduced the motor to half power at 80 watts, which was around 2/3 throttle and let it run there for a while to put the absolute worse-case condition on the system, and the ESC still ran fine.
To really push the ESC, I raised the voltage on the power supply to 11.0 volts and repeated the process, and the ESC kept on running without a problem.
I repeated these tests on 2 more 25 amp ESC's and they both ran fine on 11 volts with 1.1 amps of BEC current while powering the brushless motor at 160 watts. Based on this, I would say that the 25 amp ESC is now good to go on a 3-cell power system with 4 mini servos.
|Mar 25, 2007, 10:43 AM|
I ran the ESC at 10.5 volts to simulate the 3-cell Li-Po battery under load and ran a Scorpion 2215-22 motor with an 11x7 prop to really load down the controller. At this condition, the motor draws around 160 watts of power. I ran the motor like this for about 2 minutes at WOT and the controller barely got warm.
I can understand the ESC being okay, but what about the motor?
How are you cooling the motor, Lucien? - if I tried a full 2 minutes (or 4 minutes or 6 minutes!) static at WOT with 160W going through that 2215-22 the motor would be way to hot to hold. In my testing with a total of 90 seconds running (in 5 bursts at between 60W and 170W [an average of ~100W]) the motor got to 75C and couldn't hold a steady current draw nor rpm at its peak.
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