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Old Apr 13, 2011, 02:09 AM
hass-alfed and bass-ackwards
carlsoti's Avatar
United States, AZ, Chandler
Joined Jun 2008
5,302 Posts
Oh, dang.... I've still got my "100mph Blue wonder" sitting in the box. I guess my idea of an oversized Adrenaline Rush is going to be nearly impossible for me to see at those speeds. I may have to build a glassed foam pylon type thing for this motor.
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Old Apr 13, 2011, 12:46 PM
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Truglodite's Avatar
Carmichael, CA
Joined Feb 2007
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Still sitting in the box? Well, mine was too for a while. Yeah, after flying it during dusk and losing orientation a few times, I wish I did a brighter color scheme on top of the wing. I have a slow AR (50mph) that has a glowing pink/red/yellow/white sunburst scheme on top, and it's very easy to see like 1/4 mile away in any lighting. I'm tempted to shoot on a pink wingtip, lol!

It takes, what, like 0.1sec for it to disappear in that video? It is small for that kind of speed, but behind the sticks it honestly didn't feel at all like it was going that fast; felt like my Scrappy at 70mph. I mean, it eats up the distance pretty fast, but it also handled good enough to keep it in close without drama. What I'm getting at is there's a HUGE difference between hanging on for dear life with a 100mph epp wing, and owning the course with "mouldie class cornering". Still, 100mph around a soccer field isn't everyone's bag. A more scaled up design (like the Slipso) could make the difference between soiling yourself while driving around a soccer field and not, lol!

Good luck to whatever it goes in... please do keep us posted!
Kev
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Old Apr 14, 2011, 02:11 AM
TeachSeventh
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Houston
Joined Dec 2008
114 Posts
2730 Reply from W5BSA

Hi Kev,

Enjoyed your YouTube of your unnamed pylon racer. Nice job. If you have plans or a link to them would be interested in building one.

Been thoroughly enjoying the rewind on the 2730/12T Delta, With a 6 x 5 EMP prop getting about 16,700 at WOT, 233 watts, 24 amps on the bench.

See the youtube at
2730 W5BSA (4 min 33 sec)


Thanks again for the help. The only problem is I am staying too busy winding more for friends but that's a good thing.

Joe
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Old Apr 14, 2011, 02:22 AM
hass-alfed and bass-ackwards
carlsoti's Avatar
United States, AZ, Chandler
Joined Jun 2008
5,302 Posts
FWIW, i seem to recall that if the magnets are moving away from the motor, like the one in your video did, the effective KV goes up. This might be limiting how much power you're getting out of that motor. You should try a watt-meter test with and without the proper c-clip on there. If there's no significant change, you can ignore what I just wrote.
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Old Apr 14, 2011, 07:57 AM
Go ahead... Build it to crash!
Fuegodeth's Avatar
Conroe, TX
Joined Apr 2007
2,639 Posts
Quote:
Originally Posted by W5BSA View Post
Hi Kev,

Enjoyed your YouTube of your unnamed pylon racer. Nice job. If you have plans or a link to them would be interested in building one.

Been thoroughly enjoying the rewind on the 2730/12T Delta, With a 6 x 5 EMP prop getting about 16,700 at WOT, 233 watts, 24 amps on the bench.

See the youtube at http://www.youtube.com/watch?v=8f19pe1Yyts

Thanks again for the help. The only problem is I am staying too busy winding more for friends but that's a good thing.

Joe
Hi Joe,
I'm just a bit puzzled by your setup. I also have a 12T Delta with 24G wire. I think your prop might be a bit big for your motor.
(Edit: I see from the video that more torque/less top speed is your goal for that plane - That might be best achieved with a slightly lower kv. Maybe 13 or 14 turns of 25 or 26g would be ideal. It seems like with your current setup that it wants to pull more power, but the battery won't do it. That's a bad scenario for esc's and batteries, even though the motor is probably fine with it. Anyway, I could be wrong. I'm sure one of the other guru's will chime in soon)

Mine with the same wind is close to 2700kv. On a fresh 3s pack I get ~32000 no load, and 24,000 loaded with a 4.7x4.7 prop. That Pulls about 21 Amps at 11.8v for 247W so, that loaded RPM is about 75% of the no load RPM. That's pretty much right in the sweet spot for prop loading.

From what you have posted, you are getting 16,700 RPM with that prop on what should be a similar KV motor, so that would be 52% of the no load RPM. That's a good indicator that you have too much prop. Your amp draw is only 24 Amps for 233 watts. That tells me that the motor wants to pull more amps, but that the battery voltage is sagging under the load. Based on your stated watts/amps, the battery voltage is down to 9.7V. If you went with a smaller prop, you would probably have higher RMP, more total watts, greater efficiency and a cooler running motor. Not to mention that battery is probably getting some abuse as well. I would wager that if you took a larger battery and connected it to that setup that your amps would be much higher and eventually something will give out.

I might be wrong on all of this. I am just basing it on the information from your post, and my experience with the same wind on my 2730 that I use on my Scrappy. I hope this helps.


I have attached the eagle tree graph from my motor. The first half of it is no load, and the second half is loaded with 4.7x 4.7 graupner CAM speed prop.
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Last edited by Fuegodeth; Apr 14, 2011 at 08:10 AM. Reason: clarified my response
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Old Apr 14, 2011, 01:56 PM
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Truglodite's Avatar
Carmichael, CA
Joined Feb 2007
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Joe, no plans yet. The only computer generated drawing I made was for the wing planform. It was a hacked napkin sketch design otherwise, but I did make note of all the key numbers in my sketches. It flies great, so other than cleaning up the fuse lines a little, it's pretty much ready to share. I'll let you know when I get a set of plans/manual done.

No e-clip:
carlsoti is right... Going without an e-clip works well on pushers since the prop holds the rotor on in flight, and it helps prevent bent shafts when the rotor can pop off during a crash. With a tractor setup, prop thrust can pull the rotor out of plane. I thought I saw that rotor move out quite a bit... that'll hurt efficiency (more flux is wasted in the air... takes current to make flux). Efficiency isn't always an end goal, but it is more precious in these kind of "overpowered " applications.

The 6" prop:
The fact that your lipo lasts 6min alone tells me you're prop selection is probably OK. Peak current is working the lipos hard, but adding more lipo might mean losing combat in the corners (from the pic, losing the battle could also mean losing the lipo anyways ). It's 25awg and you're pushing it very hard, so efficiency is probably taking a dive. All things equal, if you drop a more efficient motor in, not only will RPM climb, so will amps. Seems counter intuitive that the more efficient motor would ask for more current, but spinning a prop faster is harder to do than heating up windings. As carlsoti also mentioned, a lower Kv might give you a better balance of RPM and amps. It's even possible a lower Kv might get the same RPM with less amps (depends on just how far your current setup has fallen on the efficiency ladder). I haven't tested in that area much, so I can't comment further.

Stator lams:
Out of the examples I've seen, hxt's all had 0.5mm lams, and tgy's were all 0.2mm lams. Thinner lams basically mean less "eddy currents"; this loss increases with RPM. So the higher the RPM, the more efficiency you get out of thinner lams. This makes the Turnigy a far better choice for our backyard high performance adventures. Another difference relevant only to rewinders... hxt's usually come with "fathead" style stators. You can't fit as much copper in a hxt fathead as you can a TGY. Not that I want to pay for those useless 2mm connectors they come with, but turnigy makes the better motor.

Cheers,
Kev
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Old Apr 14, 2011, 05:27 PM
Go ahead... Build it to crash!
Fuegodeth's Avatar
Conroe, TX
Joined Apr 2007
2,639 Posts
Moved to here:
http://www.rcgroups.com/forums/showt...1#post17985110
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Last edited by Fuegodeth; Apr 16, 2011 at 12:23 PM. Reason: Started a new thread for this
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Old Apr 17, 2011, 03:49 PM
Winging it >
leadfeather's Avatar
Joined May 2006
9,649 Posts
I'm planning on building a light Stryker. What is the best wind to push her along quickly?
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Old Apr 17, 2011, 10:48 PM
Dave North
timocharis's Avatar
USA, CA, San Jose
Joined Apr 2004
5,254 Posts
I know this isn't really what you're interested in, but I built a very light Stryker and put an 8040 on it. That plane was a blast to fly! Any of the typical 3S 8040 winds would work -- and weirdly, it was surprisingly quick (though not in the league you folks like to play in).

Dave
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Old Apr 18, 2011, 01:09 AM
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Carmichael, CA
Joined Feb 2007
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Nice tut' Feugo! Sorta' OT, but I retired that 6x2T-24a-Y already. I figured that plane deserved my spare MD2505, so I rewound it 7x2T-22a-Y and flew it today. Don't know exactly how fast, but it was darn fast... needs pink on the wing now, LOL!

Quote:
Originally Posted by timocharis View Post
- and weirdly, it was surprisingly quick (though not in the league you folks like to play in).

Dave
When I briefly scanned your post, I said to myself, "Dave... a Stryker? Really?" ...then I started to read the post and as soon as I got to the "very light" part and said, "Oh yeah, that one's gotta be ridiculously light... now that's the Dave I know." Incidentally I saw my first Stryker fly in real life today. Thing had like 1000W onboard, was loud as a nitro, pretty fast, and the coolest part... the landing was 100% fluff.

Kev
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Old Apr 18, 2011, 09:31 AM
Go ahead... Build it to crash!
Fuegodeth's Avatar
Conroe, TX
Joined Apr 2007
2,639 Posts
Here's a little video of my scrappy from this weekend. I finally got a decent video cam. It's a flip, mounted to my cap. Enjoy.

Scrappy TGY 2730 12T 24AWG DLRK Delta (2 min 55 sec)
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Old Apr 18, 2011, 10:31 AM
Dave North
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USA, CA, San Jose
Joined Apr 2004
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The cool thing about the Stryker is not its speed potential, but its handling. It's very stable, so at low speed you can do all kinds of weird maneuvers, including something not too unlike a waterfall. Of course, I gave it humungous throws.

Dave
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Old Apr 18, 2011, 01:42 PM
Winging it >
leadfeather's Avatar
Joined May 2006
9,649 Posts
Quote:
Originally Posted by timocharis View Post
The cool thing about the Stryker is not its speed potential, but its handling. It's very stable, so at low speed you can do all kinds of weird maneuvers, including something not too unlike a waterfall. Of course, I gave it humungous throws.

Dave
+1 Really fun plane especially if it is kept light. As the weight climbs, it becomes less forgiving when going slow; easily tip stalls. Lighter is righter.

Kev, from your previous post #758 I'm wondering if a 13t 24g abc delta would be a good choice for the Stryker and also how hard is this wind to do?
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Last edited by leadfeather; Apr 18, 2011 at 01:59 PM.
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Old Apr 18, 2011, 03:17 PM
Registered User
Canada
Joined Nov 2000
7,068 Posts
Ermm you may want to reposition your camera .
Nice tree line and lotsa beat up grass was almost all that's visible :-)
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Old Apr 18, 2011, 03:36 PM
TeachSeventh
W5BSA's Avatar
Houston
Joined Dec 2008
114 Posts
2EZ Delta Performance on the 2730 DLRK 12T Delta

Hi Kev, Stuart and Carlsoti and others,

Thanks for all the input and suggestions,

I ordered a 10 pack of 3mm C clips from Micro Dan.

Thanks for all the tubes and pictorials too. I am going to try your method of wind starting with 1 phase and the term connector, Stu, that's pretty slick.

Got the magnifying glass out and can definitely see the thinner lams on the Turnigy versus the Hex. Those little bugars can be like razor blades on some rewinds as it's easier for them to delam on the outsides an start cutting into the insulation causing shorts. Had to use some fish paper on one rewind.

I am going to try the 13 T delta too. Still running and enjoying the 12 T with the EMP 6 x 5 prop as it works good for my application with the 2EZ Delta foamy in combat. That's where I really enjoy the full range of throttle input the DLRK offers. I spend most of the time at about 30 to 40 % throttle range which puts the load according to the watt meter at about 10 amps but when I need to reach for the sky or pull a high G turn the power and torque with the EMP 6X5 is there waiting for me to make the kill.

Stu, I noticed you're in Conroe, I bet I have met you at the Best Electric
Fly in at New Waverly in the past.

Hope you guys have a great week,

Joe

2730 red black dlrk (4 min 45 sec)
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