Exi 500 Helicopter - Carbon Edition - RC Groups
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May 18, 2010, 06:17 PM
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Exi 500 Helicopter - Carbon Edition

Records and data for my EXI 500.

Post #2: Components & Costs
Post #3: Setup, Programming, Performance & Data
Last edited by gtfreeflyer; Jul 27, 2011 at 11:17 PM.
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May 18, 2010, 06:30 PM
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Components & Costs

Listed as, Item: Product / MSRP Price / Price I Paid / Tax / Shipping / My Total / New or Used / Where Bought

Necessary components:
Airframe: Exi 500 Carbon Ed._________________ / $139.00 / $129.00 / $12 / $11 / $152.00 / New / xheli.com
Main blades: Align 425D CF Blades, P/N H50104_ / $49.99 / $35.00 / $0 / $0.00 / $35.00 / New / RCGroups
Motor: Scorpion HK-3026-1600_______________/ $74.99 / $71.95 / $0 / $5.25 / $77.20 / New / rcdude.com
ESC: Castle Creations Ice 75A_______________ / $119.95 / $85.00 / $0 / $0.00 / $85.00 / New / RCUniverse
Gyro: JR G7703D__________________________ / $189.99 / $80.00 / $0 / $0.00 / $80.00 / Used / Friend
Tail servo: Futaba S9257___________________ / $59.99 / $41.00 / $0 / $5.00 / $46.00 / New / eBay
Cyclic servos (3): Align DS510_______________ / $149.97 / $98.99 / $0 / $6.95 / $105.94 / New / eBay
Receiver: Futaba R617FS___________________ / $99.99 / $85.95 / $0 / $0.00 / $85.95 / New / eBay
Battery: Blue LiPo 6s1p, 2650 mAh LiPo, 40C_____/ $49.83 / $49.83 / $4 / $0.00 / $54 / New / hobbypartz.com
Battery strap: 300x20mm____________________/ $1.00 / $1.00 / $0 / $1.00 / $2.00 / New / helidirect.com

Paddles: Align CF__________________________/ $12.99 / $10.00 / $0 / $0.00 / $10.00 / Used / RCGroups
Tail rotor shaft assembly: Align H50037_______/ $7.99 / $7.99 / $0 / $1.00 / $8.99 / New / helidirect.com
Tail shaft bearings: Align 684ZZ_____________/ $6.99 / $6.99 / $0 / $0.00 / $6.99 / New / LHS
Tail blades: KBDD 70mm neon yellow_________/ $5.99 / $5.99 / $0 / $1.00 / $6.99 / New / helidirect.com
Main blade damper: Align 85 black H50022___/ $3.99 / $3.99 / $0 / $1.00 / $4.99 / New / helidirect.com
Hardware: Misc hardware 12.9 grade________/ $10.00 / $10.00 / $0 / $0.00 / $10.00 / New / Hardware store
Canopy nut/grommet: Align________________/ $1.99 / $1.99 / $0 / $0.00 / $1.99 / New / LHS

Cost offsets:
The ICE came with a coupon for a free Castle Link, which I already had, so I got another and sold it for $15. I got another one too and sold it for $20.

MSRP value: $989
I paid: $729 plus $48 tax and shipping charges minus $35 offset.
I already had the receiver and gyro, so it cost me $565 - so far - to add this heli to my fleet, upgrades included.

Crash & Repair Costs:
Incident #1: $30. Tail blew out during a low hover. Heli forced quickly down to the ground. Landed hard on skids, nice and square to the ground. Picture below.
___Landing Skid - Replaced with Xheli brand. $4.91 + shipping.
___Base plate - Replaced with Xheli plastic base plate. $3.90 sale price + shipping.
___Tail rotor shaft assembly - Shown above, under upgrades.
___Tail blades - Shown above, under upgrades.
___Tail control pushrod
Incident #2: $5. Temporary nose weight (a big allen wrench) fell out during an inverted hover and struck & bent the flybar. Luckily, it missed the paddles and main blades.
___Flybar - Replaced with Align flybar from the LHS.
Incident #3: $4.56. 7/27/2011. Got too low during an inverted hover. Main blades scuffed the dirt, but did not seem to affect heli's performance. It sure was a crowd pleaser Recovered heli and landed to assess the situation. Scraped tiny amount of paint off of the Align 425D main blades. Carbon fibers still in tact without damage. Upon spooling up the heli again, heard ticking. Shut down once again and found one tooth of the main gear was missing.
___Main gear - Replaced with another EXI500 main gear from xheli.com

I'm well aware of the fact that I could have just bought an Align T-Rex for this cost. However, one of my favorite things about this hobby is to research the components and pick out which ones I like. I like putting the whole heli together piece by piece. It gives me that feeling of "I put this all together myself". Align doesn't offer this option, so my money went elsewhere. I like trusting my own opinion about components needed, even if it means I must learn from my mistakes. That's the way I learn. Everyone shops differently. Would I have bought an Align if they sold just the kit, no electronics included? Maybe, maybe not. I never looked into it because the option was never there to begin with.
Last edited by gtfreeflyer; Jul 27, 2011 at 11:16 PM.
May 22, 2010, 12:12 PM
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Setup, Programming, Performance & Data

Canopy Nuts:
Drill 3/16" holes in the canopy for the canopy nuts. Deburr the sharp edges of the holes with a dremel or file. I tried a 5/32" hole and it was tough to insert the canopy nut onto the stud on the heli, and both canopy nuts tore apart after a few installations. A 3/16" hole seems to be the right size for the canopy nuts.

Servo Arm Lengths:
Cyclic: 19.5mm
Tail: 10.5mm. The next hole in is 7mm from center and would not give me enough range on the tail slider.

Pitch Curve [Radio] (Degrees):
Th.Hold: [38, 45, 49.5, 67.5, 100] (-4, -2, 0, +5, MAX PITCH (approx 14 or 15 deg))
Normal: [38, 45, 49.5, 67.5, 86.5] (-4, -2, 0, +5, +10)
IU1: [13.5, 35, 49.5, 67.5, 86.5] (-10, -5, 0, +5, +10)
IU2: [8, 35, 49.5, 67.5, 96] (-12, -5, 0, +5, +12)

Throttle Curve:
Th.Hold: Throttle point set to 10% which sends a 1.05ms signal. This enables me to bail out of an autorotation without having to go thru the slow spool up.
Normal: 0, 57.5, 57.5, 57.5, 57.5 (Governor set to hold 2500 RPM except for lowest stick position).
IU1: 57.5, 57.5, 57.5, 57.5, 57.5 (Governor set to hold 2500 RPM throughout stick range).
IU2: 68, 68, 68, 68, 68 (Governor set to hold 2800 RPM throughout stick range). It doesn't look like this is possible with a 13T pinion. Ground test showed 100% power to motor was req'd to maintain 2800 RPM with collective at zero deg.

Swash Mix:
Aileron: -45%
Elevator: +45%
Pitch: +42%

True Gain: 12%. My mechanical gain is too high, but to reduce it I would need to move the tail servo ball closer to center. The next hole in does not give me enough slider range.
I never fly in rate mode. I'm always in headlock mode even during spool up. I never bothered to set up the revo mix.

ESC Settings: (note: My heli is not optimally set up and these settings will change!)
################################################## #####
# Castle Link Data File
# Created: Wednesday, July 18, 2010
# Do Not Edit This File By Hand
################################################## #####
Hex55: 85
Brake Strength: 0
Brake Delay: .6 sec (Delayed) (*)
Brake Ramp: Immediate (*)
Cutoff Type: Soft Cutoff
Motor Start Power: 39 (This is the low setting. You don't need too much initial power for a slow spool up anyway).
Direction: Forward (*)
Sample Frequency: 2 Sample / Sec
Motor Timing: 5
Data Log Enabled: 245
Current Limiting: Disabled
BEC Voltage: 5
Power-On Beep: Enabled (*)
PWM Rate: 8 Khz (a bunch of online reviews said to use this setting with the Scorpion motor).
Vehicle Type: Helicopter
Throttle Type: Governor Mode
Throttle Response: 5
Governor Gain: 20 (did not notice much difference coming down to 15 from 20, but 12 was too low. I liked 20 the best of the 3 values I tried).
Initial Spool-Up Rate: 4 (3 was a little too slow for me, probably around 10-12 seconds).
Head Speed Change Rate: 7 (lower values seemed to be too gentle on the main gear and spool up too slow for an autorotation bailout).
Auto Rotate Enabled: True
Governor Mode Type: High
Auto-Lipo Volts/Cell: 3.0 Volts/Cell (*)
Cutoff Voltage: 90

--Mod #1: Removed aft-upper and aft-lower screws from the tailbox. These are not necessary and were causing my tail shaft to bind in the bearings when all screws were tightened down. If you look at the Align tailbox it also has only one screw (picture below).
--Mod #2: Added spacers (washers) under one of the tailbox's sides. When tightened down, the spacing between the tailbox sides at this location was slightly different than the spacing between the sides at the aft-most point, which caused the two sides to not be parallel and this also contributed to my tail shaft binding in the bearings. With this mod combined with mod #1, my tail shaft now spins super smooth and friction-free (picture below).
--Mod #3: Grounded tailboom to prevent static discharge, which is a problem with 500 size helis. I scuffed the forward end of the boom to remove the protective coating until I could see bare aluminum. I did the same thing inside the boom mounting block. The protective coating is not conductive, so you'll need to have the bare aluminum of the boom touch the bare aluminum of the boom's mounting block. Use a multimeter and check resistance between the boom and some screws towards the front of the heli. You should have some resistance which means current is able to flow from the boom to the frame.
--Mod #4: Wrapped one layer of scotch tape to the aft-end of the boom, and had the tailbox clamp over this tape. The tailbox needs some extra grip on the boom. If you think it's tight without the tape, then you are underestimating what high-frequency vibrations can do. You really need extra grip! How do I know? Answer is here.
--Mod #5: Locked skid pipes to skids. I drilled a 1/16" hole thru the skid and one wall of the skid pipe and stuck a M2x6 screw in there to lock it up. Only necessary on one of the skids (front or rear). You'll want to leave the front or rear skid free to slide on the skid pipe to allow movement during landing to help absorb shock (picture below).
--Mod #6: Replaced the metal pushrod for the tail with a CF rod that has threaded couplers JB Welded onto the ends (picture below).
--Mod #7: Added "Chinese weights" to tail (picture below).

All up weight: 4.17 lbs
Current draw: Hovering= 12A. Slow patterns around the field= 12A with occasional ~35A spikes. (see Data Log #1 below)
Temperatures: On a 70 deg day, I measured 105*F on both the motor and batteries (Two Flightmax 30C 2200mAh 3s packs in series); ESC stayed cool as well after 5 minutes hovering and slow flight.
Tail: The tail is unbelievable. I can't believe how hard it stops and how crisp it feels. Money well spent. It holds extremely well on hard punches to the collective. Fast backwards flight is solid as the tail holds very well. I can pull it into a vertical climb, let it tailslide back towards the ground at high speed, and then pull out of the freefall and go straight into a backwards loop without the tail blowing out on me. Very solid.

Data Log #1 (see picture below): 13T pinion. Governor gain=20. Spool up rate = 3. Head speed change rate = 7. Motor start power = 39. Motor Timing = 5.
Last edited by gtfreeflyer; Oct 23, 2015 at 07:03 PM.
Jun 03, 2010, 01:20 AM
Registered User
vinay2070's Avatar
Thats one hell of a setup, Will surely kick align. Am planning to go with HK500GT (same as EXI plastic). Just wanted to know where did you get the 9257 at such a good price?
Jun 16, 2010, 04:25 PM
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First flight accomplished today. I only hovered, but it was great. I could feel the power that was just waiting to be unleashed. Blade tracking was spot on, and vibration was not obvious, other than a boom support screw backing out of the frame... twice! A little CA and I'll be good to go again.
Jun 25, 2010, 12:50 PM
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First "crash" report and pictures.
Jan 30, 2012, 05:05 PM
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Align part compatibility

Here's a quick reference for parts I have had to replace and have verified fit in the Exi500:

H50040 Tail Boom T-Rex 500
H50022T Damper Rubber / Black 80
H50023 Feathering Shaft T-Rex 500
H50037 Tail Rotor Shaft Assembly (purchased, waiting to check compatibility)
H50086 Main Shaft T-Rex 500
H50195 Swashplate Leveler Tool (purchased, waiting to check compatibility)
KBDD4035 72.5mm Tail Blade Set w/5mm Root (purchased, waiting to check compatibility)

Tail rotor shaft bearings: 684ZZ 4x9x4mm
Tail drive gear shaft bearings: 684ZZ 4x9x4mm
Last edited by gtfreeflyer; Oct 30, 2015 at 11:28 AM.

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