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Old Oct 24, 2012, 09:27 PM
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I have the Spin 200 and I do have a programmer. I wasn't actually planning on running up to 15S though. Maybe maybe 14... but I was actually hoping to get away with just 12. It's going in a 1/10 scale Yellow F18. I'm already a little worried about the weight though. Its recommended flying weight is around 12-13 lbs but I think with this fan, the scale landing gear and the Spin 200, it's going to weight 15 or 16 lbs. What do you think?
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Old Oct 25, 2012, 08:50 AM
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Oh

You show 29 pounds on 16 cells @ 205 Amps so going up almost 100 amps or 50% does not seem like a good way to get 2 more pounds of thrust. Also a 3 pound jump from 15 to 16 cells. I am guessing here but ill bet it hasn't been run there.

You list the 16 cells with a 6800 mAh battery and if I am using 12,000 then I am thinking ill get more than 205 on 16 cells.

I thought it would be much more. The more I find out about this the farther I seem to be able to get to your advertised 20KW

How about the efflux with a 3.5" exhaust? Not sure the CFM and id need that to compute
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Old Oct 25, 2012, 11:46 AM
Xtreme Power Systems
Lake Havasu, AZ
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Quote:
Originally Posted by mulicheng View Post
I have the Spin 200 and I do have a programmer. I wasn't actually planning on running up to 15S though. Maybe maybe 14... but I was actually hoping to get away with just 12. It's going in a 1/10 scale Yellow F18. I'm already a little worried about the weight though. Its recommended flying weight is around 12-13 lbs but I think with this fan, the scale landing gear and the Spin 200, it's going to weight 15 or 16 lbs. What do you think?
LOL! If you came in at 20 pounds you will be thrilled. Our Yellow F-15 weighs 28.5 pounds, and flys 131MPH (flat and level) on a 12S setup. That is the *exact* same speed as our G130 turbined powered version of the same plane. Vertical is better with the turbine because of the higher static thrust, so the airframe drag is the limiting factor. Check out the video of that F-15 flying. I am flying a Cermark F-16 at 18 pounds with a 102mm (cut down from 127mm) Dynamax setup. Almost all of the videos you will find our fan system are in aircraft that are in the 22-25 pound range. If you build the bifurcated pipe correctly, you should lose about .5 pounds of thrust compared to a single pipe setup. On 12S, you should be seeing at least 14 pounds of static thrust with the losses of the inlet ducting and exit nozzles.
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Old Oct 25, 2012, 11:50 AM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
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Quote:
Originally Posted by Air Head View Post
You show 29 pounds on 16 cells @ 205 Amps so going up almost 100 amps or 50% does not seem like a good way to get 2 more pounds of thrust. Also a 3 pound jump from 15 to 16 cells. I am guessing here but ill bet it hasn't been run there.

You list the 16 cells with a 6800 mAh battery and if I am using 12,000 then I am thinking ill get more than 205 on 16 cells.

I thought it would be much more. The more I find out about this the farther I seem to be able to get to your advertised 20KW

How about the efflux with a 3.5" exhaust? Not sure the CFM and id need that to compute
Remember, battery capacity is directly related to the amperage capability. In order to have more thrust (higher RPMs) you need less voltage drop. So, you could definitely have a case where there is more thrust on 16S/20000mah than 18S/5000mAh just because of the voltage sag under load. Also keep in mind that flight times are dependent on amp draw. A system pulling 200A on 5000mAh batteries is going to last a little over 1 minute before the pack is depleted, and your top speed will only be good for about the first 15 seconds.


The motor itself will handle 23Kw before the windings melt (with absolutely no cooling). This is how we obtained our 20Kw figure. I only know a couple of people that have ran it beyond the 10kw figure because it is frightening.

We have never measured efflux with a 3.5" nozzle as that is not a size that we use. With a 3.375" exit nozzle, the efflux on 15S is 280MPH. on 16S its well over 300MPH. We didn't design the Dynamax, but this information is readily available from various sources. No matter what turns the fan, the thrust and efflux per RPM is going to be the same for the same fan.
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Old Oct 25, 2012, 11:52 AM
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Well I want a lot more than 131mph. I have a GP Revolver that can do 120. It's nice for a fixed wing glow engine. For a Jet this size I want a little more though

I have to keep up with Paul you know
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Old Oct 25, 2012, 06:31 PM
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Allright then

I am thinking that the speed limit is going to be 38,000 rpm because of the speed controller.

Is this correct?

How did you run the motor at 23KW and what was the RPM. I am thinking it may have just been loaded with more than what the fan does - so when you say the motor will handle it was it hooked to the fan during the test?

10,000 watts is only halfway to where I want to be with this and if your saying its scary on 16 cells and you only know a few that have run that.

Could you tell me the safe limits for operation of this setup. I really dont want to blow this up.


"Custom made 20Kw outrunner motor (10S to 18S, or 20Kw)"

I am sorry to be hung up on this but it looks like it states 18S or 20Kw.
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Old Oct 25, 2012, 09:05 PM
Xtreme Power Systems
Lake Havasu, AZ
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Quote:
Originally Posted by mulicheng View Post
Well I want a lot more than 131mph. I have a GP Revolver that can do 120. It's nice for a fixed wing glow engine. For a Jet this size I want a little more though

I have to keep up with Paul you know
Well, you saw how fast Paul's Maverick was. Keep in mind that F-18's, F-15's, etc. are extremely draggy airframes. When a turbine with 32 pounds of thrust won't push a 30 pound plane any faster than 131MPH, and a 28.5 pound version with only 14.5 pounds of thrust is the same speed, you KNOW there is an airframe issue. If you want a faster F-18 or F-15, you need to go with something that is not scale. ie. no washout and clipped wings.
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Old Oct 25, 2012, 09:13 PM
Xtreme Power Systems
Lake Havasu, AZ
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Quote:
Originally Posted by Air Head View Post
I am thinking that the speed limit is going to be 38,000 rpm because of the speed controller.

Is this correct?
Absolutely! The controller is key to the success of this. We have blown up a LOT of Castle HV120, HV140, and HV160 controllers on 12S with these fans because of commutation errors due to the high RPMs and high pole count. So far, the most reliable controllers have been the ones we were selling and the JETI SPIN 200.


Quote:
Originally Posted by Air Head View Post
How did you run the motor at 23KW and what was the RPM. I am thinking it may have just been loaded with more than what the fan does - so when you say the motor will handle it was it hooked to the fan during the test?
The factory that builds our motor ran it until it melted. We both had to know where that point was. It was under some amount of load, but I am not sure what they were driving (probably a wheel or something). At 23Kw the motor windings melted. But during this test, there was no air blowing over the motor.


Quote:
Originally Posted by Air Head View Post
10,000 watts is only halfway to where I want to be with this and if your saying its scary on 16 cells and you only know a few that have run that.

Could you tell me the safe limits for operation of this setup. I really dont want to blow this up.
The system has been proven for years on 15S, and run on 16S quite a bit as well. Only on the bench have we run more (never flown). This new version without the c-clip notch is much safer as the shaft is the full 8mm (not 6.5mm like it was where the notch is cut). This and the new blades that Tom Cook made (improved blade material) make this the safest version we have sold to date.


Quote:
Originally Posted by Air Head View Post
"Custom made 20Kw outrunner motor (10S to 18S, or 20Kw)"

I am sorry to be hung up on this but it looks like it states 18S or 20Kw.
That is correct. Up to 18S or 20Kw, whichever comes first. It is possible to exceed 20Kw on 17S, depending on the voltage drop.
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Old Oct 26, 2012, 07:33 AM
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Quote:
Originally Posted by JimDrew View Post
Well, you saw how fast Paul's Maverick was. Keep in mind that F-18's, F-15's, etc. are extremely draggy airframes. When a turbine with 32 pounds of thrust won't push a 30 pound plane any faster than 131MPH, and a 28.5 pound version with only 14.5 pounds of thrust is the same speed, you KNOW there is an airframe issue. If you want a faster F-18 or F-15, you need to go with something that is not scale. ie. no washout and clipped wings.
True True... I was actually interested in this plane more for the scale appearance than for speed. It does say right in the manual (old manuals of course) that it's standard flying speed is 160-170.
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Old Oct 29, 2012, 12:33 PM
Xtreme Power Systems
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Yeah, that's why they say about the F-15 with a turbine too... but we have radar'd enough of them to know that they don't go that fast.
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Old Oct 29, 2012, 12:43 PM
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Guys are flying the F18 over 150 with EDFs though. On 12s too. Note that the F15 is twice the weight of the 1/10 F18 I believe... depending on what you power it with.

Time will tell on this one. I've collected a good portion of the building stuff I need and hope to start seriously working on it soon.
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Old Oct 29, 2012, 06:37 PM
Xtreme Power Systems
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One thing you will learn very quickly with EDFs and and jets is that weight only matters when you are trying to land. Drag doesn't care what a plane weighs.
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Old Oct 29, 2012, 06:41 PM
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Yep... this isn't my first EDF. Just my biggest. So like I said... guys are flying this exact jet 150+ with 12s. In the YA F18 forum it was commented just recently when I was discussing which power system to put in it.
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Old Oct 31, 2012, 11:35 AM
Xtreme Power Systems
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The single version is smaller than the F-15. I have seen these fly on 10S 90mm and 100mm fans.
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Old Oct 31, 2012, 08:34 PM
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Is there a problem wth the one I have?

This new version without the c-clip notch is much safer as the shaft is the full 8mm (not 6.5mm like it was where the notch is cut). This and the new blades that Tom Cook made (improved blade material) make this the safest version we have sold to date.
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