Originally Posted by Kaw1000

I'm not seeing any 4.5 x 5.5 props
there is a 4.5 x 4.1
http://www.radicalrc.com/category/APC-E-Props-208
http://www.allerc.com/props-apc-prop...cts_sort_order

Sorry, my mistake, I meant 4.75 X 5.5. This one:

http://www.apcprop.com/ProductDetail...tCode=LP04755E
http://www3.towerhobbies.com/cgi-bin...?&I=LXPJG8&P=7

I would try what you have now, as long as you have the 2 X 2S 1300mAh you can do it with what you have i.e. 16/15/4 and 40A ESC. This will be a very good setup. Later you can try other setups if you want.

Notice from the uploaded attachment that you are operating at almost peak efficiency with this setup and nicely within the specs of all your components . For a small boost you can go to these batteries:

http://www.horizonhobby.com/Products...=THP13002SPP65

- Birger

Thanks...this is the set up I will use for now! You have been most helpful!

Check these lipos out...see what you think....http://www.allerc.com/hyperion-g3-cx...ck-p-4647.html

1/2 the price of the Thunder powers

Originally Posted by Kaw1000

Thanks...this is the set up I will use for now! You have been most helpful!

Check these lipos out...see what you think....http://www.allerc.com/hyperion-g3-cx...ck-p-4647.html

1/2 the price of the Thunder powers

Those will work for sure, hyperion are great packs. If you are aiming for a temporary setup while you decide what your final setup will be I would also consider these:

http://www.hobbypartz.com/77p-sl1300-2s1p-40c-2222.html

At that price you can nearly think of them as disposable

- Birger

wow...now thats a great price....I do not plan on going any higher that 4 s on this little bird. So these look like a keeper!

Originally Posted by Kaw1000

wow...now thats a great price....I do not plan on going any higher that 4 s on this little bird. So these look like a keeper!

Not exactly what I meant, I was referring to going with a different motor and possibly a 3S setup once you "get bored" with your initial. I am currently on my second setup and just coming to grips with it but who knows, there may be a 3rd one in my future:

1st: 250W
2nd: 450W
3rd: ???

- Birger

I don't plan on changing it up as I have other hotliners. I also have another pylon in the pipeline that I will make super fast.

I'm a little confused on the calculations and what they mean...is pitch speed how fast it will go? And watts in, meaning going from esc to motor and watts out, meaning out the prop?

Jacko, thanks for that data... archived the 3T stuff.

Kaw, you say that about upgrading now, but it's a Voodoo. Unless you get like a Sergey stinger or something, this is going to be your "fast 400".

No, pitch speed does not equal "how fast it goes". It is related to how fast you go, but in reality a plane can settle in to level WOT flight above or below pitch speed. Slippery models like the Voodoo usually end up a tad faster than pitch speed, a draggy 3d model would go far less than pitch speed.

Motor geeks use this terminology:
Watts in = power to the motor
Watts out = power to the prop
Watts out = Efficiency * Watts in

This is critical info to learn and make use of! Efficiency is what you pay for... and of course more efficiency makes the plane faster.

We don't say "Watts in = Watts out = watts to the prop + motor heat", although that would be more techinically correct as it adheres to energy conservation. If we talked that way then concepts of motor heat, power output, and efficiency would be easier for many to understand.

Kev

Got it! Thanks

Does anyone know how this setup would perform in a s400 pylon racer (Voodoo or D2000, for example)?

Neu 1105 2.5Y (kv = 3800)
3s 2100 mAh
4.7x4.7 GM folder
cc45

Here's what a motor calculator says:
44 A
378 W (out)
Prop Pitch Speed: 148 mph
Thrust: 53 oz
RPM: 33,333
Motor Run Time: 2:52
Efficiency: 85.3%

AEM

Voodoo is sp400, D2000 is F5D (larger class). I found an archived discussion on that seems relevant (scroll down past half way to rcelectfly's post):

https://www.rcgroups.com/forums/arch.../t-673329.html

Bob used a 4.5x4.1 and rce' was content with a 4.1x4.1. So my guess is a 4.7^2 folder is too much for racing (>1min WOT), but as a hotliner (brief bursts of WOT) it'll probably work fine.

Cheers,
Kev

[edit: With a newer low internal resistance lipo, you would drawing even more power. So a 4.1 prop with 60A esc, or the 4.7 folder with a 60A esc or more would be prudent.]

Originally Posted by Truglodite

I found an archived discussion on that seems relevant

Thanks. It looks like you're right; 4.7x4.7 is probably too much for the 2.5Y. I happen to have a 2.5 Y already, but I also have one of the folders. So, I think I'll just spring for a 16/15/3 since that is tried and trued.

ok, I have ordered my powerplant
this is my first voodoo so gonna start slow(ish):
1300 3 cell
B2849/9 motor
4.75 x 4.75 prop
40a esc
hopefully that will be a good recipe for fun!?

Got a link to the motor?

Voodoo is always fun, more watts = more fun

Ill try get some footage of my tamed down limping voodoo tommorrow, I think I wouldve liked this 2S setup a lot more if I hadnt have been flying the voodoo on 650W before it.

I couldnt get a link but this is the spec:
Shaft Size:3.175 X1 2.0(mm)
Motor Dimensions:28.0 X 47（mm）
Max Amp: 42
Watts: 529
Weight: 132g
Kv: 3600
Idle current: 1.8A
Resistance: 0.0141

what do you reckon on 3 cell, 4.75x4.75, 40a esc?

Too big a motor I think man, it'll mean less battery space and a lot of weight in the nose to balance out.

You want a speed 400 sized motor - ~ 28mm x 37mm ~80grams

That motor is heavier than a S480 motor (ie 16/25 28-48 etc), It weighs the same as a 16/30

You'd be looking at more like 60A if it did fit BTW, if you want a cheap motor, look at ARC 28-37s, theyre not brilliant, but will be better than generic chinese inrunners.

Originally Posted by AEMontoya

Does anyone know how this setup would perform in a s400 pylon racer (Voodoo or D2000, for example)?

Neu 1105 2.5Y (kv = 3800)
3s 2100 mAh
4.7x4.7 GM folder
cc45

Here's what a motor calculator says:
44 A
378 W (out)
Prop Pitch Speed: 148 mph
Thrust: 53 oz
RPM: 33,333
Motor Run Time: 2:52
Efficiency: 85.3%

AEM

I fly with that NEU motor and it rocks. I fly with a APC 4.1x4.1. It easily flys over 150 mph. I also went to a 3s 1800. 2100 works fine too.

Originally Posted by hybris

I fly with that NEU motor and it rocks. I fly with a APC 4.1x4.1. It easily flys over 150 mph. I also went to a 3s 1800. 2100 works fine too.

Cool. It seems like this setup provides a whole lot of speed for how little it weighs. A few questions, though:
1) The motor calculator shows 37 oz thrust. Is this sufficient for a D2000 that will weigh about 18 to 19 oz? I mean, would take-offs and acceleration be a bit of a pain?
2) Will this setup require cooling holes for the motor?
3) Can partial throttle be for periods of, say, 30 sec - 1 minute if a cc45 is used?
4) What minimum C rating would be needed for the battery with this setup?

Just as a reminder, the setup is: 1105 2.5Y (3800 kv) + 3s 2100 mAh + 4.1x4.1.

A Motor Calc says this (for 3s 2100 mAh):
Current: 27 A
Power: 255 W (Out)
RPM: 36,700
Efficiency: 89.6%
Thrust: 37 oz
Prop Pitch Speed: 143
Motor Run time: 4:38

Thanks

Those numbers are screwy AEMontoya. Id imagine you'd be looking at at least 450W to acheive 36700 rpm.

It takes a very efficient 350W to get 35k rpm with a 4.1x4.1 in real life.

Originally Posted by jackosmeister

Those numbers are screwy AEMontoya. Id imagine you'd be looking at at least 450W to acheive 36700 rpm.

It takes a very efficient 350W to get 35k rpm with a 4.1x4.1 in real life.

Interesting. If that's true, the calculator is really missing the mark. Well, I suppose the calculator should at least be more or less accurate when comparing one setup relative to another. On that note, here's a little compilation I put together for my top choices. Any comments/preferences/advice are welcome.

One thing I like about the two Mega motor setups shown in the chart is that they can ge upgraded (namely, the 16/15/2 and 16/15/3 can also be used with 3s and 4s, respectively). I also like the fact that the mega motors can be used with a 4.7x4.7 folder. The 16/15/2 seems to be the more appealing of the two Megas in the sense that it can be upgraded to 3s, which does not require an external BEC, unlike the the 16/15/3 on 4s. However, the 16/15/2 on 2s may be borderline with the cc45 that I have, especially since I hope to be able to use a decent amount of partial throttle if desired. So many choices!

It is true

FWIW, an ARC 37-2 (3750kv) runs efficiently spinning a 4.1x4.1 at 34k rpm from 350W, 35k from 350W would be an uber efficient motor, 36700 from ~290W would be awesome, but is well over 100% efficiency, so quite unlikely

Ive never tested that Neu, but Id imagine, educated guesstimate, You'd be looking at 37A for 35k rpm. Or somewhere around 135-40mph depending on plane.

The mega's do have useful kV's for stepping up later, but as everyone says theyre not cheap. Id run the /2 on your CC45 on 2S without worry, 3S needs a 60A esc.

Its personal preference, Ive popped too many esc's, but if it goes faster than 100mph Id run a seperate bec, the CCBEC are a handy size and if your esc goes up in smoke you still have control.

Here's what Bob (at SUSA) had to say about the 2.5Y that he used in his Quick (allegedly, if flew at over 150 mph):

At MWE the set up was;
1105/2.5Y
CCPHX 45
TP 2100 gen II
4.5x4.1

Now, I prefer
1105/2.5Y
CCPHX45 or 60
NeuEnergy 2100 or TP 2070
4.1x4.1

-----------------------------------------------------------------------------------------------------------------------------------------
Yeah, I think I will try to find a CC10A for cheap. They're pretty light and small, and it's better to be safe than sorry. On another note, would an AR 6100 (microlite parkflyer RX) be safe in a D2000?

Its possible the kV of the neu isnt accurate, in that case you may get enough rpm for 150mph straight and level, but amps are gonna go up too.

Theres pics at the start of this thread of a voodoo with an AR6200 in it from memory. 6100 is playing with fire. D2000 is quite a big bigger than a voodoo, should have plenty of room.

I don't know about the calculations but my voodoo has to do at least 150 mph flat and level. I can't get radar on the voodoo. I had the same setup in a VIP and radared it in the 140s level. 160s in a dive. The voodoo is faster. I did get radar in a turn and it was in the 160s but I don't know what kind of error that is inducing. I am using 30c 1800s and run full throttle for 4 minutes straight. No heating issues. 3300rpm static and it definitely winds up in the air. Never needed a folder. Grass landing have only eat about on prop per 10 flights or so. And that is usually a botched landing. The 4.1x4.1s do get stress marks after a few flights. I am pulling most of these numbers from memory. Been flying this Voodoo for few years now. I have personally seen Bob's quick fly 7 or so years ago in San Diego on a old school thunder power 2100. It was 150+. His son flew the whole flight at full throttle doing rolling circles. It was insane even to todays standards. I really like Neu Motors. I just recently had a Microjet powered by a Neu 1107 on 4s radared both directions at 154 mph average flat and level. That was some fast foam.

...well I imagine they would be more like rolling octagons or something.

Kev

what servos should I be putting in my voodoo?
I have a whole load of turnigy micro servos but they are too wide for the job :-(

Originally Posted by lukeydukey10

what servos should I be putting in my voodoo?
I have a whole load of turnigy micro servos but they are too wide for the job :-(

I used the recommended (?) servos:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNCW1

They fit well and perform admirably. I have them in the stock location with trimmed leads and running a 1600 3S. It's tight but it does close. If you want to see my setup let me know and I will post some pictures.

- Birger

A plane like this needs and deserves better than a Turnigy servo; the gear slop in a cheap servo can actually result in a midair breakup (flutter) if you have enough speed, and that's not to mention how poor centering affects your course...

Dymond D47's are were just about the default standard on s400 racers for years, and still are a safe bet to save a few bucks versus buying digitals (they work better on racers than many digitals actually):

http://www.rc-dymond.com/index3.php?productID=176

I've been saving up to try MKS450's on my next small speedster:

http://www.soaringusa.com/products/p...ategory_id=269

I hear those Mark Star servos are something else... even better than D47's.

Kev

Double post.

Originally Posted by bdelapen

I used the recommended (?) servos:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNCW1

They fit well and perform admirably. I have them in the stock location with trimmed leads and running a 1600 3S. It's tight but it does close. If you want to see my setup let me know and I will post some pictures.

- Birger

+1

Great little servos for the voodoo.

hi berger
please can you send me pics?
I hope I go down the correct route with these servos
I dont like the idea of fitting a new mounting plate or piece of wood like others have done and would like to mount them where they are supposed to go... I just hope it all fits in!!
Any pics would be good guys