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Old Dec 15, 2009, 08:48 PM
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Mini-Review
Grayson MicroJet V3 (39g, ~2300kv)

Basil at www.graysonhobby.com kindly sent me this small outrunner, the result of much work, in association with Welgard, to produce a parkjet motor, lighter, but almost as powerful as, the excellent 54g Supersonic V2 (GH2212-06, ~2180Kv). http://www.rcgroups.com/forums/showt...=supersonic+v2, http://www.rcgroups.com/forums/showp...88&postcount=4

This new motor (http://www.graysonhobby.com/catalog/...tor-p-425.html) weighs in at 39g, has a 3.17mm shaft, and is obviously a 2208-platform motor, whereas the SuperSonic V2 is a 2212. Initial no-load and prop runs suggested (using Motocalc) a Kv of ~2300Kv, Io of 2.05A @ 10v, and an Rm of ~0.15 ohms.

I started out with a 4.1x4.1 EMP on 7v-11v from the Zurich Power Supply, then tried 4s using an EVO 2150 pack (15.30A/204W gave me 14.79oz @ 94.9mph). I tried a 4.7x4.7 Graupner CAM then moved to a series of ~5x5 props (APC E, EMP, Graupner CAM, Zagi and Maxx). These all drew ~17-18A and generated varying thrust in the mid-high 80's mph. The Zagi generated the most thrust with the greatest efficiency (18.13oz @ 87.7mph from 16.95A/181W), and the 5x5 APC E generated the least thrust, least efficiently (13.17oz @ 89.1mph from 16.80A/179W). In none of these runs did the motor get alarmingly hot. Even the 6x4 APC E which produced 23.56oz @ 68.1mph from 19.80A/212W and the 6x5 EMP (25.52oz @ 85.6mph from 18.45A/195W) did not generate a huge amount of heat. I imagine that with in-flight cooling one could push this little motor even harder. It ran smoothly throughout and, considering it is 15g (almost 30%) lighter than the Supersonic V2, it performed admirably, generating only a fraction less thrust and speed than did the Supersonic V2 with comparable props.

Enjoy the numbers!

Cheers, Phil
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Old Dec 16, 2009, 08:11 AM
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Clarifying the confusion.

I've tested a lot of "Suppo-like" motors [http://www.suppomodel.com/], not necessarily from exactly the same source, but variously labeled as Suppo, Welgard, Grayson, BP etc, and even in my mind there is some confusion about what is what. I have not tested any motors with green/black labels which were strictly Welgard http://www.bphobbies.com/view.asp?id=A2586784. As far as I can tell the motors BP sells under their label are straight Suppo... some of these are the original 'A' series and some the later 'U' (Ultimate) series http://www.bphobbies.com/view.asp?id=C3481958.

The new Grayson MicroJet V3 is not the same platform as the Supersonic V2. It is a 2208, the SuperSonic V2 is a 2212.


1. As far as I can tell, the base platform for this new GH MicroJet V3 is somewhat comparable to a Suppo 2208/x. The machining is different, the magnets are different.... as expected since it is a Grayson/Welgard product. Among the first 'genuine' Suppos I tested was a Suppo 2208/8 provided by Dave Skokan at Lightflight.... I also received some directly from Joe Siphers at Suppo-Ruihui. This motor (along with its 2208/12, 2208/14 and 2208/17 variants) weighed ~38g and had a shallow (5mm thick) backplate, a 10.5mm deep magnet ring and a 3mm shaft. Motocalc indicated ~2720Kv. I also tested for Todd (www.toddsmodels.com) a variety of 2208 and 2212 motors which looked exactly like Suppo 'A' series, but which he called Suppo-Welgard.

2. The first version of the Suppo 2212/6 which I tested was the “original Gold version” (also from Lightflight) which weighed 51g, had a 3mm shaft, a deep (6.25mm) back plate and a magnet ring depth of 14.30mm. Motocalc indicated ~2315Kv.

3. A later Blue version of the Suppo 2212/6 weighed 55g, had a shallow (5mm) backplate [but not exactly the same as the one on the 2208], a 3.2mm shaft and had the bell and front plate as an integrated unit...overall the bell was a fraction shorter than that of the Gold 2212/6. Motocalc indicated ~2150Kv. This one, I think, was what BP listed as 'U' series.

4. Lightflight sent me several 2217K motors (/6, /7, /8, /9) which had larger shafts (4mm, not 3.2mm) than the original 'A' series. These may also have been what others called the 'U' series.

5. Basil at Grayson then sent me an all-silver SuperSonic V2 http://www.graysonhobby.com/catalog/...tor-p-398.html (GraysonHobby, at one time, listed this as the MicroJet GH 2212/06). This weighed 54g, with a 3.2mm shaft, and had a different deep (6.50mm) backplate with countersunk mount screw holes. The magnet ring of the bell measured 14.60mm, but the front plate of the bell was exactly the same as that of the Gold 2212/6 (though all silver, not gold).

6. Most recently, I have the GH MicroJet V3. This weighs 39g, has a 3.2mm shaft, the thinner 5mm backplate (identical to that of the Blue 2212/6... thinner-walled than that of the Suppo 2208s), and a two-piece bell with a 10.5mm deep magnet ring. Motocalc indicates ~2300Kv. It is clearly a 2208 variant, not a 2212.

7. I have also tested, again from GraysonHobby, some SuperCruise motors which were 2212 variants, various MegaJets (18/21/23) which were 2215 motors (and did not have the Suppo appearance) and several versions of the SuperMegaJet which was a 2217.

Are we thoroughly confused yet?
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Old Dec 16, 2009, 08:03 PM
GRAYSON HOBBY
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We have / had about 2-3 "REAL" manufactures send us prototypes in the past we sent you, but ever since we released our orginal parkjet, MANY MANY MANY clones have been released.

You know the old saying...The pioneer takes the arrow in the back
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Old Dec 16, 2009, 08:06 PM
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Quote:
Originally Posted by Lt.Smash View Post
We have / had about 2-3 "REAL" manufactures send us prototypes in the past we sent you, but ever since we released our orginal parkjet, MANY MANY MANY clones have been released.

You know the old saying...The pioneer takes the arrow in the back
Wear a Kevlar vest at all times! I understand your frustration, Basil, but you have a really good product here... hang in there! 200W+ through a 39g motor, without excessive heating, even under "worst case scenario, static testing, in pusher mode, no less" is remarkable.
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Old Dec 18, 2009, 12:14 PM
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A picture of the MicroJet V3 in comparison with the SuperSonic (GH2212-06) V2.

One additional snippet of information: The stator laminations on the MicroJet V3 are 0.28mm (21 lams in 7.5mm).
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Old Dec 30, 2009, 03:57 PM
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Just for fun: here is an Eagle Tree plot for the test series with a 6x5 EMP (five brief bursts at 7v-11v).
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Old Jan 07, 2010, 06:45 AM
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Dr. Kiwi,

How would you say the this V3 stacks up to the 2212/6 V2 efficiency wise (thrust/W) on a 6-4E?

MGeo
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Old Jan 07, 2010, 10:06 AM
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The slightly larger SuperSonic V2, as expected, is marginally better... the difference is presumably the fact that this big a prop is more of a load for a 39g higher (2300) Kv motor than for a 54g lower (2180) Kv motor:

6x4 APC E

Micro Jet V3: 10.7v, 19.80A, 212W, 17970rpm, 68.1mph, 669g, 23.56oz, 3.16g/W

Super Sonic V2: 10.7v, 20.60A, 220W, 18660rpm, 70.7mph, 721g, 25.39oz, 3.28g/W [more thrust at higher pitch speed, and a bit more efficient too]
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Old Jan 08, 2010, 04:04 AM
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OK thanks. That's closer than I thought it might be.

I'll look at a Zagi Carbon as well. Can you tell me how you mounted it to the 3.17mm shaft for you test?
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Old Jan 08, 2010, 08:49 AM
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Quote:
Originally Posted by MGeo View Post
OK thanks. That's closer than I thought it might be.

I'll look at a Zagi Carbon as well. Can you tell me how you mounted it to the 3.17mm shaft for you test?
You may need to settle for a 5x5 Maxx since I think that Zagi Carbons are no longer available... but the Maxx is close. I bore out the hub to 5mm and use a 3.2mm collet adapter.
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Old Jan 09, 2010, 04:48 PM
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i have a suppo 2208-8 from rchotdeals.com, how does it stack up against this new V3 from grayson?
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Old Jan 09, 2010, 06:52 PM
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The Suppo A2208-8 which I tested came out as ~2720Kv, so a lot hotter than the MicroJet V3 (~2300Kv). On 3s it should probably be limited to 4.7x4.25 or 4.5x4.1... with a 4.75x4.75 or a Zagi it draws 21A and gets pretty darned hot. On 2s it can just manage a 7x4 APC E.
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Old Jan 10, 2010, 02:57 PM
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well i guess i'll run the 2208-8 with a apc 6x4(on 2s) in the new mig from rcpowers that i just built till i can get one of these new V3's! thanks for the info
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Old Jun 08, 2010, 07:39 AM
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MicroJet v3 and ESC

Hi there guys, i'm thinking about buying this microjet v3 in Grayson Hobby,
they have this combo that consist in:

- microjet v3
- 20 AMP ESC
- 1600 mAh 3 Cell battery

I have some questions about this, can one 20Amp ESC hold continuous discharge rate of 20C (32 Amps) without burning?

In some Dave Powers video he get the microjet v3 running on one 2200 mAh 3 cell battery, this battery have an continuous discharge rate of 20C (44 Amps) and i think he was using one 20 Amp ESC. This 20 Amp ESC hold 44 Amps coming from the battery?


thanks for the attention.
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Old Jun 08, 2010, 10:00 AM
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Quote:
Originally Posted by OxyG3n View Post
Hi there guys, i'm thinking about buying this microjet v3 in Grayson Hobby,
they have this combo that consist in:

- microjet v3
- 20 AMP ESC
- 1600 mAh 3 Cell battery

I have some questions about this, can one 20Amp ESC hold continuous discharge rate of 20C (32 Amps) without burning?

In some Dave Powers video he get the microjet v3 running on one 2200 mAh 3 cell battery, this battery have an continuous discharge rate of 20C (44 Amps) and i think he was using one 20 Amp ESC. This 20 Amp ESC hold 44 Amps coming from the battery?


thanks for the attention.
You have a misconception.... the motor/prop determines the amp draw from the pack... whether the pack can supply 100A or 44A or whatever doesn't matter.... if the motor is propped for only 20A... that's what the battery will be asked to deliver.

Why would you draw 20C (1600x20 = 32A)... the motor is rated for about 20A!

On the question of the ESC, though, if you are drawing 20A continuously, then you really need bigger than a 20A ESC... 25A or 30A would be a safer bet... especially for cheap ESCs which are somewhat over-rated.
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