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Old Mar 15, 2010, 12:56 PM
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fred_n's Avatar
Virginia Beach, VA
Joined Aug 2009
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Quote:
Originally Posted by Lee View Post
To have the smallest fin with the greatest effect it needs to be slightly toed in at the back end of the wing.

I have been looking at trying the mini angle fins on the larger planes like the Titan and Grim Reaper. I will probably cut several designs and put velcro on the fin and the velcro on the angle and try them on the angles to see if they work.
That sounds like a cool experiment. Please show us a picture of your experimental placement(s) and let us know of the results.

Someone recommended to me to stick the velcro strip on blue painter's tape. That way you can move the velcro strip around by moving the tape without having to peel the velcro strip off your wing/plane. Saves on velcro too.
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Last edited by fred_n; Mar 15, 2010 at 03:10 PM. Reason: Additional thought
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Old Mar 16, 2010, 10:20 PM
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USA, TN, Nashville
Joined Oct 2009
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I'm trying to decide on a motor and batteries and stuff for this plane... It'd be nice to run it off 2s 300-450mah (something I could use on my 3depp.com yak 55 as well)... I'm gonna go with the hxt500 5g servos from hobbyking. I'm terrible at picking out motors. Any suggestions? I'm game to try something new.
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Old Mar 16, 2010, 11:12 PM
I HOOVER because I SUCK!
Portland,Oregon U.S.A.
Joined Sep 2007
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Originally Posted by rdbell View Post
I'm trying to decide on a motor and batteries and stuff for this plane... It'd be nice to run it off 2s 300-450mah (something I could use on my 3depp.com yak 55 as well)... I'm gonna go with the hxt500 5g servos from hobbyking. I'm terrible at picking out motors. Any suggestions? I'm game to try something new.
any of the 12mm bl inrunners will work- but limited prop selection -anything over 3" will not work- so are limited to 3x2 or 3x3 prop

I personally would go for the 10g 2000kv type motor- good on 2-3s and have lots of prop choices- even 6-7" on some- can get good speed for pretty little weight

or do a blue wonder/cd-rom type- usually about 20-24g and about 3000kv

have one that is fast on 2s and ballistic on 3s- have used it in wings `16" to 28"

first one I used that motor on was the 16" goliath on 2s was fast- on 3s would top over 100mph easy

was insane for a 16" wing

loved it!

I use little 2s 400 alot for smaller wings

but size of batteries main purpose is to balance the motor!

mk
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Old Mar 16, 2010, 11:18 PM
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USA, TN, Nashville
Joined Oct 2009
903 Posts
Could you give me a link to the one you're talking about? I'd like to use a 4-6" prop on 2s. What were you using on yours?

100mph is insane by the way for that tiny thing.
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Old Mar 16, 2010, 11:37 PM
Sorry, but they're all toys.
Eric Odle's Avatar
United States, WA, Bellingham
Joined Jun 2009
292 Posts
That 10g 2000kv motor is here:
http://www.hobbyking.com/hobbycity/s...idProduct=5358

But it looks like HK is out for the moment... Here's a blinged-up version of the same motor:
http://www.hobbyking.com/hobbycity/s...idProduct=8613

Any of the 6 amp ESC's will run it on 2s. I'm sizing my elevons for a 6" prop, which should draw around 4 amps with the 2000kv motor.

Just check out HK's list of outrunners, sort the list by price and click on the last few pages.

You might consider the 3800kv version of the 10g outrunner if you want more speed at the expense of a higher-pitched, whinier motor. Then you'd want a system that can put out 7 amps or so to feed that kind of power.

I've found the inrunners to be heavy for the power output, though my 12mm 4000kv Medusa does pretty well at 15g or so. It would probably give vertical authority to a Scythe that comes in under 125g using a 4x2.5 prop.
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Old Mar 17, 2010, 12:38 AM
I HOOVER because I SUCK!
Portland,Oregon U.S.A.
Joined Sep 2007
5,141 Posts
mounting the inrunners is easier imo

just make a hard bed/cradle for it and ziptie

if you are using the larger props, there are a lot of lower kv motors at HK

most of the larger wings use <2000kv motors

main consideration is prop torque of larger props on smaller wings

but over 24" really any of these motors would make a nice wing-

mk
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Old Mar 17, 2010, 12:54 AM
Sorry, but they're all toys.
Eric Odle's Avatar
United States, WA, Bellingham
Joined Jun 2009
292 Posts
Travelling Scythe Motor Mount and Layout

Here's a closeup of my 1g motor mount and a general layout of my Scythe. Everything is mounted into the left wing and will overhang into pockets cut into the right wing. The plywood tray in front is a 4g structure to solidly support the battery, which will likely be somewhere between 300 and as high as 600 mAh, depending on whatever balances the rig. The 4mm tube spar is cut into two pieces and joined with a solid stub spar. Two pairs of rare-earth magnets, one pair just in front of the spar and the other just in front of the battery, hold the assembly together. They're quite strong so hopefully getting the thing apart won't be too difficult, as all equipment is completely buried between the wing halves. To change batteries, you have to pull it apart, hence the magnet approach to make changing batteries as simple as possible. I figure I should come in around 120g AW, and with a 6" prop on the 10g 2000kv motor with 2s, I should be able to produce around 140g static thrust.

If death ever decided to take a vacation, he might bring this scythe along in his checked baggage!

My camera seems to be working at the moment so I'll post some more pics as I progress.
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Old Mar 17, 2010, 02:44 PM
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Ontario, Canada
Joined Aug 2008
27 Posts
Motor, ESC, Battery and Servo Options...

I own a Hyperflea (22" delta EPP plane) and given it's similar in size to the Scythe, I thought that the motor, ESC, battery and servos in use there might be a good place to start on the Scythe. My only concern is they all appear to be larger/heavier than what is being talked about here in the forum. Here's the components the Hyperflea uses:
  • Emax CF2805 (29g)
  • 12-18A ESC (?)
  • 2s 700-900mAh Battery (~48g)
  • BlueBird BMS-306BB (6g)

Are these too heavy for a 30" Scythe (don't plan to cut it down) in everyone's opinion? I have an Assassin and went with the recommended hardware and it works great. With the Scythe I'm hesitant to just guess and so am looking forward to hearing what others are using. Thanks.

Nathan
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Last edited by nlodoen; Mar 17, 2010 at 03:38 PM. Reason: change wingspan dimension from 24 to 30"
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Old Mar 17, 2010, 05:39 PM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
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I just flew Scott's Scythe with the following radio. I flew it with both 2 cells and 3 cells. It was real sweet. With 3S it will go straight up with this set up but it will glide amazingly well with the CG at 4.5" back from the nose.

Scythe Beta Testing with the following: This is not an ultra light build but a combat build. He let me put some stripes on it for a couple of pictures.

Battery - http://www.hobbycity.com/hobbycity/s...idProduct=6470 or http://www.hobbycity.com/hobbycity/s...idProduct=7449
Motor - http://www.hobbycity.com/hobbycity/s...80kv_%2827g%29
Motor mount - http://www.hobbycity.com/hobbycity/s..._%2843/42mm%29
Servos - http://www.hobbycity.com/hobbycity/s...0.8kg_/_.12sec
ESC - http://www.hobbycity.com/hobbycity/s...rogrammable%29
Push rods and plastic clevis' stock Parkzone ultralight.
Standard horns pushed through elevon from bottom.


Lee



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Last edited by Lee; Mar 17, 2010 at 06:11 PM.
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Old Mar 17, 2010, 05:56 PM
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nalby's Avatar
USA, NY, New Hampton
Joined Jan 2005
689 Posts
hey Lee what's the wingspan on scott's wing? and what is your cg. I'm using 4" back from the nose but it feels real twitchy I think I have to move it forward a bit.
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Old Mar 17, 2010, 05:59 PM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
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Quote:
Originally Posted by nalby View Post
hey Lee what's the wingspan on scott's wing? and what is your cg. I'm using 4" back from the nose but it feels real twitchy I think I have to move it forward a bit.
His is the full 30". It flies great. It was fun to see it flying with the Titans and Reapers today. He kept using bigger and bigger batteries for weight to get the CG far enough forward to where it was stable. Once the CG was right it flew like a dream. It hardly needs any throw on the elevons and loops and rolls great.



.
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Last edited by Lee; Mar 17, 2010 at 09:19 PM.
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Old Mar 17, 2010, 07:23 PM
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USA, TN, Nashville
Joined Oct 2009
903 Posts
Alright thanks! I'm gonna go with the 3800kv version as the higher pitched sounds don't really bother me and I wanna go fast I'm gonna use a 5x3 GWS prop... HXT500's and some small 2s... Hobby King is out of stock of a LOT of stuff.. Like esc's, almost every battery, motors... What's going on?
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Old Mar 18, 2010, 09:30 AM
Sorry, but they're all toys.
Eric Odle's Avatar
United States, WA, Bellingham
Joined Jun 2009
292 Posts
Quote:
Originally Posted by rdbell View Post
Alright thanks! I'm gonna go with the 3800kv version as the higher pitched sounds don't really bother me and I wanna go fast I'm gonna use a 5x3 GWS prop... HXT500's and some small 2s... Hobby King is out of stock of a LOT of stuff.. Like esc's, almost every battery, motors... What's going on?
Still recovering from the Chinese New Year I bet. Must be a real party!

There is a domestic source of some HK items here:

http://www.rcfoam.com/cart.php?targe...ategory_id=152

Most of their motors are lower kv though.
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Old Mar 18, 2010, 09:47 AM
Sorry, but they're all toys.
Eric Odle's Avatar
United States, WA, Bellingham
Joined Jun 2009
292 Posts
Quote:
Originally Posted by Lee View Post
Interesting servo, metal gears and less than 5g? I gotta wonder about the weight on that one, HK's specs are notoriously flawed sometimes. It'd be nice to have something a little tougher than the usual plastic gears.

Any idea what kind AUW were flying?
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Old Mar 18, 2010, 11:49 PM
THAT'S WHAT SHE SAID!!!
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Joined Aug 2009
84 Posts
I am not able to make any purchases yet, I'm saving for the Reaper stuff first, but these are the items I am considering for the Scythe so far. Input from anyone is welcome.

I didn't cut the cores down at all (aside from making them square and then toeing them in the suggested 3/8"), the wing span is 30.25"

http://www.hobbycity.com/hobbycity/s...idproduct=9608
- These are the batteries I am going to start buying a lot of. They are 3S 40C 1050mAh and can be charged at 5C! (reviews say they charge in about 12-15min at that rate) This way ALL my models will use the same batteries and all have extreme performance! I'll be using two in parallel on the Reaper.

http://www.hobbycity.com/hobbycity/s...idproduct=5428
- I'm thinking about using this motor with the suggested prop size of 5x3. HK says it will produce about 357g (~12.6 oz) of thrust with that prop.

http://www.hobbycity.com/hobbycity/s...idproduct=8609
- Same servos as Lee has suggested. I had these picked out prior to his post. Great minds think alike, eh?

http://www.hobbycity.com/hobbycity/s...idproduct=6548
- Same speed controller too. Again, I had these picked out prior to his post. Maybe we are just crazy....

I am approximating the total weight to be less than 250g (<9oz). Does this sound reasonable or about right?
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