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Old Mar 12, 2005, 05:04 PM
Current project: Electrolyte
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United States, OH, Dayton
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micro Stinger

There has been alot of interest in smaller racers lately and I couldn't help but also jump on the band wagon. Little electric racers really test your reflexes and I love a challenge.

Using KrisS's fantastic little cylidrical fuselage, I am going to build a smaller 24" version of the well known speed 400 Stinger racer.

The wing is going to be a fully composite hollow molded when completed. Currently the wing plug is finished and the next stage is to mold. Time has been spent making the plug as accurate as possible without the use of a CNC machine. The plug is made from balsa, ply, and fiberglass. The ply is located in the trailing edges to give me a straight and sharp edge. I intend to use KrisS's recommendation for power:
Razor 400
CC pheonix 10
TP 900 3s

The wing pictured with the smaller Stinger wing is an old VIP that died due to radio interference.
In case you haven't seen a standard Stinger in person, here is a picture of Jimmy Rosenthal with his at the 2005 MWE.

I hope that this model can hit the magic 100mph barrier.
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Last edited by pdawg; Mar 12, 2005 at 06:00 PM.
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Old Mar 12, 2005, 06:34 PM
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United States, MI, Commerce Charter Township
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You could call it the "Weevionik"! I've been thinking about something simliar myself, just don't have the time..

Dave
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Old Mar 12, 2005, 06:50 PM
RIP Ric
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Marietta, GA
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Quote:
Originally Posted by pdawg
I hope that this model can hit the magic 100mph barrier.
A stock stinger will hit 100 in a shallow dive with a mere speed 400 motor..
..a
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Old Mar 13, 2005, 02:02 AM
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Thanks for posting some pictures
That little wing of yours looks fantastic, great job so far
Judging from the picture the wing is very thin, and the Razor/TP combo will have enough power to achieve 100mph with ease
I set up another of my racers today, Razor-2500 with Irate 1100 3s pack and Graupner CAM Speed 4x3.2 prop, that's the absolute maximum that will fit into the tiny fuse. Total weight with that setup is 203g, 29k rpm drawing 18A static

Keep up the good work and keep us posted!
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Last edited by KrisS; Mar 13, 2005 at 08:27 AM.
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Old Mar 13, 2005, 07:17 PM
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Hey PDawgie..... nice looking forward to hearing more.. what size prop do you plan on using with the razor 400.. on 3s 900mah cells???
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Old Mar 13, 2005, 07:39 PM
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As usual, outstanding work!!!! Looks like its 100mph standing still!
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Old Mar 13, 2005, 08:20 PM
Current project: Electrolyte
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For this particular setup KrisS has suggested an APC 4.1x4.1 prop. KrisS has been toying with racers of this size for some time and has tested a variety of power systems. But since the "Weevionik" (thanks Dave) is still in the construction phase, I have not had the chance to actually see this power setup perform first hand.

shhhhh!
Thanks for the compliments. Hopefully the finished product will turn out nice and straight also
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Old Mar 14, 2005, 01:58 AM
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Quote:
Originally Posted by pdawg
For this particular setup KrisS has suggested an APC 4.1x4.1 prop. KrisS has been toying with racers of this size for some time and has tested a variety of power systems
The APC 4.1x4.1 will work in this application, just make sure to set the overcurrent protection to 'insensitive' or 'disabled' when using a Phoenix-10 esc since the amp draw will be in the 15A range, plus make sure to have good cooling.
A very nice and efficient prop is the Graupner CAM Speed 4.0x3.2, the only disadvantage is that they break very easily, so I just ordered a batch of 30 from Hoellein.
Another possibility is the GWS 4x4, needs a little sanding though around the hub to make it fit the spinner, plus it makes nasty vibrating sounds if not perfectly balanced...
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Old Mar 14, 2005, 05:48 PM
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I have found the apc 4.1x4.1 thick in the airfoil.. more suited for nitro motors the prop does load down electric motors more then a gws 4040 the cam speed 4X3.2 makes for a good prop thinner airfoil but being only a 3.2pitch your not going to get as much top end speed as the gws 4040 ... to go over 100mph you really need that 4pitch. The 4040 starts to stall and make that whaleing sound past 24k .. when held static. The thinner the airfoil and lighter the prop makes a world of diffrence in run time and top end.
The apc 4.1X4.1 wasnt made for electrics the hub and root of the airfoil is beefed up for nitro.. and isnt a true elect prop.

You can cut down a gunther black carbon prop it's rated as a 5X5 or 130x125mm prop cut down to a 3.7X5 makes for amazing pitch speed and top end past 22k on sub 5oz planes.
Another trick is taking a gws 5043 and cuting it down to 4043 the extra pitch does make a diffrence over the 4040 .. the gws light thin airfoils are king for run time and speed but will fail if you push them past 27k your motor wont be strong enough to cuase a problem.
apc 5.5X4.5 is a true elect prop with a thiner airfoil at the hub and cut down to 3.7X4.5 will out perform all the other props above mentioned.

KrisS I would like to buy a few cam speed 4X3.2 props have you heard of a source for them in the US ? with a pitch of 3.2 you will need to push them in the 25k range to get solid 100mph plus speeds.

All my info is based on using the CC 10amp esc..on 2S the fets are rated at 15amps
I wouldnt recomend setting to insensitive though, if there is a short in the system the esc will be fried, I do set mine low to allow over current passed 10amp.

I tried the himax 5400k motor with a gws 3030, amp draw was high and strained the 10amp esc somewhat. The real let down was 3 pitch didnt reach the 100mph mark in the air on 2s 1320's.
3.2pitch on 3S sounds like a winner. would love to try a few cam 4x3.2's on 2s at 14amps.. think I can get around 27k at those amps.

Will check with hobby lobby in tenn .. they have the new micro foam reno racer that uses that prop on a 180 size motor if I recall.
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Old Mar 14, 2005, 07:55 PM
Mark Triebes
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We're using a modified GWS 4.0x4.0 on our foamy Nemisis' . . . mine is spun by a Himax 2015/5400 at around 26,500 ... pulls right at 14 amps with a Kokam 340 2s2p.

Top speed radared so far is 85 mph ... this little foamy was never meant to go quite this fast and gets a bit flexy and twitchy at these speeds.
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Old Mar 14, 2005, 10:08 PM
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Marcus, Is that the Graupner Nemisis?
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Old Mar 14, 2005, 10:29 PM
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2s2p is good for 12amps bursts in the 14amp range but that still sagging the packs.. might be better to prop down.. the spinner is a killer as far as adding amps (load) to the motor. Unloaded in the air the static rpm should have shot up some amps down in the 11a range.. the 5400 motor needs 2s 1320's just to spin a HD3030 for 6mins..with no spinner load. Do you have a pic of the modified 4040.. 3540 should give you some breathing room amp wise . Im sure the kokams dont hold 26.5k static for more then 40seconds before they sag .. Seen some new 1100's that are rated at 20C think by kokam. You could improve performance by sealing up the air gap on the back side of the prop where it comes out of the spinner ..balsa block fitted and sanded to fill in the void.. what we all really need here are custom spinners and carbon props. Marcus would like to try the Nimisis on a light cd rom motor and 2S 900's. What is your all up weight with the current setup? I can get 23k with a uncut 4040 and 2s 850's
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Old Mar 15, 2005, 12:13 AM
Mark Triebes
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Hey Troy . . . yeah, it's the Graupner Nemesis . . . Steve C and I special-ordered a couple of them back in December and got them a few weeks before Hobby Lobby started selling them to the masses . . . they're a real kick to fly . . . with a hot brushless setup, they almost have an F5D feel to them . . . aerodynamically, they're far from perfect, but if you put enough power into them . . .

Amp User . . . the photo is my modified 4.0x4.0 . . . it's clipped down to 3.25 diameter and slimmed a bit chordwise . . . it actually works quite well in this configuration . . . the 340 2s2p is not the ideal choice, just what I had that would work at the time . . . Steve C is running the Eflite 370/4100kv motor with a TP730 2s pack and it's probably a better fit for the plane . . . he's about 40 grams lighter than I am (mine's a pig at 175 grams).

These micro racers are kinda addicting . . . Steve and I are thinking about where to go from here: a little Miss Ashley? maybe a Nemesis NXT? Pond Racer anyone?

Mark
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Old Mar 15, 2005, 01:11 AM
Current project: Electrolyte
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United States, OH, Dayton
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Its great to have input from several modelers who have first hand experiences with micro high performance planes. It seems to me that the available products (brushless motors, props, spinners, etc.) are very limited at this size. I hope more products come out in the near future that are more taylored to this class of models.

Hey Troy,
Hopefully this smaller Stinger is as stable as the one you launched at the MWE. I was impressed that the strong winds didn't seem to bother the Stinger much. That flight is what sold me on this wing design.
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Old Mar 15, 2005, 01:58 AM
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@Amp User

I see you have been playing around with small props as well
I don't know where the CAM 4.0x3.2 are available in the US, I ordered mine from www.hoellein.com in Germany, vendor with excellent service and good prices, worldwide shipping, they cost 1.90 Euros each.

Yesterday I hooked up a freshly charged TP900 3s pack to the RZ-400 with GWS 4x4 prop, that battery has punch, amps went up to 18A
So I sanded the prop down to 3.5x4.0 to reduce current draw, further tests will follow.

I also played with a CC Mamba 3600 motor, the performance compared to a Razor is rather disappointing, definetely worth to spend a few more bucks and get a Razor instead.
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Last edited by KrisS; Mar 15, 2005 at 02:04 AM.
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