T-Rex 250

Ordered 18th April 2009 and built throughout April and May.

This is a new 200 series micro-helicopter from Align, announced in late 2008. Engineered to the quality expected for a T-Rex. There were a few initial problems with the tail but it was quickly handled and fix with a new metal replacement.

The build requires extra attention to details and precision when setting up the links, angles, aligning, and leveling due to the small scale of the helicopter.

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My Kit

• T-Rex 250 Super Combo
  • Updated tail grip, 1 bearing (instead of 2)
  • CF frame 1.2 mm (instead of 1.0 mm
  • Hex screws 0.9 mm (still old, newer models have 1.3 mm)
• Spektrum DX7 heli transmitter, incl. 9.6V 1500 mAh NiMH battery
• Spektrum AR6100e 6 channel micro-receiver
• Outrage 860 mAh and Thunder Power 910 mAh batteries

Download the manuals:

• T-Rex 250 Combo manual - Nov. 2008
• T-Rex 250 Super Combo manual - Feb. 2009
• T-Rex 250 SE manual - Sept. 2009
• Align RCE-BL15X manual - Extracted from T-Rex 250 SE manual

250 SE

In late August 2009 Align released the improved T-Rex 250 SE. The main differences are a all shiny silver metal head, rotor holder, improved CCPM plate for better 3D, new bearings in washout and mixer arms minimizes slop, upgraded tail with even more grip weights reduces servo load, exchangeable main gear, new more efficient 250SP motor, new anti-rotation guide, and 1.3 mm headed screws standard. It's a revised T-Rex 250, all the new parts are available as upgrades (29 right now).

• Official Align T-Rex 250SE product page
• Align forum T-Rex 250SE news posting - translated from Chinese
• T-Rex 250SE Super Combo details
• Align T-Rex 250 “SE” Details Released!

Setup

• T-Rex 250 Setup - Detailed configuration of CCPM, pitch, tail, gyro, and radio
• My T-Rex 250 Parts - List of parts, upgrades, and tools used for the build
• Bantam data cable - Shows how to create a data cable for Bantam compatible chargers

Upgrades

This is a list of possible upgrades, it includes third-part manufacturer parts as well as Align's own upgrades and revised spare parts.

See the parts I've gotten:

• My T-Rex 250 parts list

From what I've found the following notation at the end of the Align partnumbers designates the type of change done to the part:

• -1 or 1 - Minor revision of the part to fix a design flaw or obvious fault, e.g. fixed tail hub bearings, longer tail control arm
• A - Upgraded part, offers additional functionality compared to the old part, e.g. 1.3 mm hexagon screws (most parts)
• F - Color difference, silver mostly, e.g. new silver parts for 250SE
• Q - Metal part, silver mostly, e.g. seesaw holder, head stopper
• New number - All new part all together, e.g. new exchangeable main gear, metal version of parts

Item	Stock	Upgrade / Replacement [1] [2]
Swash/collective Servos	Align DS410 12.7g	Hitec HS-65MG [3] JR DS287MG JR DS285 (helihobby sugg) Hitec HS-5065
Tail Servo	Align DS420 12.7g	JR DS290G / DS380G in uk JR DS3500G (big) [4] Hitec HSG-5083MG (+HG-5000) Futaba S3154 (burnout) Futaba S9650 (big) [5] Futaba S9257 (also big) [6] Align DS520 [7] Logitech 3100G (+2100T) Spartan Servo Database
Gyro	Align GP750	Spartan DS760 [8] [9] Hitec HG-5000 (Rebranded 2100T) Futaba GY520 Futaba GY401 Logitech 2100T [10] CY Mini-G [11]
Receiver	None	Spektrum AR6100/AR6100E
Battery	None	Outrage NRG XP30 3S1P 11.1V 860mAH 30C - 85g New July 2009 Outrage XP25 3S1P 860mah 25C - 70g Thunder Power 910mAh 3SP1 11.1V Pro-lite Lipo V2 16C TP910-3S - 73g Thunder Power RC Pro Power 30C 3S 850mAh 11.1V - 74g Align 3S1P 11.1V 850mAh/20C KX880002A - 68g Hyperion G3 CX LiPo 850mAh 25C 3s HP-LG325-850-3S - 68g New July 2009 Kong Power 3S 11.1V 850mAh - 70g Hyperion G3 VX 3S 1100mAh 35C - Big 97g Zippy Flightmax 800mAh 3S1P 20C - Cheap 78g [12]
Motor	Align RCM-BL250 3400KV 9-pole	Scorpion HK-2208-3600 Scorpion HK-2206-3900 [13] [14] Align RCM-BL250SP 3400KV
ESC	Align RCE-BL15X 15A JST	YGE 1+ProgCard [15] Castle Creations 25A ESC
Pinion	15T	Venom 16T (3D) Align 16T
Receiver Power	ESC BEC	Medusa Potencia 5V/2A BEC MR-BEC-35020 [16]
Other upgrades		Body and main rotor KDE Aliminium Bottom Bracket AT250-BBU [17] [18] Extreme Production Metal Battery Mount AT25005 [19] Align New Exchangeable Style Main Gear H25096 [20] Align Metal Main Shaft Bearing Blocks H25077 1 [21] Extreme Production Main Shaft Bearing Blocks [22] Extreme Production Graphite Swash Guide AT25006 [23] MicroHeli Carbon Fiber Anti-Rotation Guide MH-TX2001S [24] MicroHeli Main Gear One-way Bearing Hub MH-TX2102 [25] Gaui G-203250 Bearings on Upper and Lower Mixer Arms [26] [27] Boca Rotor Head Bearings 250HEAD [28] [29] TrueBlood Feathering Shaft Dampeners DAMPENERS10 [30] Align 205D Carbon Fiber Main Blades H25072 [31] Outrage Paddle 200 Size RG20167 [32] [33] Tail drive and tail rotor Align Metal Tail Drive Gear Assembly H25079 [34] - Already on newer kits Align Metal Tail Boom Mount H25094 [35] Infinity Hobby Tarbo Carbon Fiber Tail Boom [36] [37] Align Carbon Fiber Tail Boom H25091 [38] Align Metal Rudder Servo Mount H25076-1 [39] Flying Sport Carbon Fiber Rudder Push-rod FS1209 [40] Western Robotics 5.1V Step Down Regulator [41] - for Futaba servos Infinity Hobby Super Tail Kevlar Belt [42] Align Metal Tail Rotor Shaft Assembly H25075 [43] Align New Tail Rotor Hub (2x instead of 4x bearings) H25074-1 [44] / H25074A [45] (250SE) - Already on newer kits Align New Metal Tail Rotor Control Arm H25092 [46] Align Tail Rotor Control Arm H25062-1 [47] - More Resolution Align New Tail Rotor Holder Grips w/ Weights H25095 [48] / More Weights H25095A [49] KBDD Tail Blades 40mm 4mm [50] Align Tail Blades 37mm H25084 [51] Align Carbon Fiber Tail Blades 40 mm Curved Batman Style H25093 [52] Other Align 1.3 mm Hardware Bag - Screws and Washers H25033A [53] Align 1.3 mm Stainless Steel Linkage Balls H25055A [54] Align Special Washers 0.9 mm H25054 [55] / 1.3 mm H25054A [56] Align Lightning Yellow Painted Canopy H25050 [57] 250 SE upgrades [58] Metal Main Rotor Holder Set H25003A [59] - Strengthened Metal Rotor Housing H25004A [60] - Strengthened Metal Flybar Control Set H25006A [61] - Strengthened Metal Washout Control Arm H25011A [62] - Strengthened, better bearings Metal SF Mixing Arm Set H25013A [63] - Strengthened, longer throw, better bearings CCPM Metal Swashplate H25016A [64] - More throw Anti Rotation Bracket Set H25044A [65] New Metal Tail Holder Set H25095A [66] - More counter-weights Metal Tail Belt Unit H25026A [67] - New control arm mount Landing Skid Set H25034A [68] - More durable and height Canopy Mounting Bolt H25039A [69] - Strengthened And I use the T-Rex 250 Super Combo manual or T-Rex 250 SE manual for the rest of the parts

• Align T-Rex 250 topseller parts list - lower left menu

Third-part upgrades

List of third-party spare part and upgrade part manufacturers:

• Xtreme Production - Shop: Miracle Mart - Making metal replacements of tail control link, main shaft blocks, tail boom mount, tail servo mount, battery mount, and swash guide
• Infinity Hobby [70] - Making custom carbon fiber boom and skids, and lots more
• Microheli - Shop: Flying Hobby HK - Metal anti-rotation guide, and various aftermarket parts
• Flying Sport - Shop: Helidirect page - Carbon fiber tail rod

Spare part sites

Good websites to get T-Rex 250 spare parts and upgrades:

• flying-hobby.com - HK, clean site, 3rd-party upgrades, good prices, latest parts
• helipross.com - Clean site, discounts
• rc-uwants.com - HK, clean site, 3rd-party upgrade, discounts
• readyheli.com - Clean site, 3rd-party upgrades
• heliguy.com - UK, user-friendly site
• fast-lad.co.uk - UK, good design, lots of 3rd party upgrades
• helidirect.com - Huge inventory, 3rd-party upgrades upgrades, canopies
• elefun.no - Norwegian, local, fast shipping
• espritmodel.com - Clean site, great inventory
• helikraft.com - Discounts
• rcpowersupply.com - HK, discounts
• horizonhobby.com - No intl. shipping
• miracle-mart.com - HK
• hobby-wing.com - HK
• boomtownhobbies.com - 3rd-party upgrades

Things to note

• ESC comes with JST plug for the battery, maybe change to a higher rated 50A Deans connector for less heat, larger connector surface
• Add a piece of zip tie between the tailboom pushrod to secure
• Threadlock to all metal-to-metal screws, only a slight drop on the tip of the screw
• Use purple threadlock on most high-service areas and blue threadlock on other essential areas (head, engine, tail) or all, green threadlock on outer rim of bearings, red permanent threadlock on really essential areas (not really needed on T-Rex)
• Use CA super glue for all metal-to-plastic screws
• Add silicone shock oil to the belt to ease and smoothen the movement, eliminates build-up of static electricity
• Silicon spray for the belt, TriFlow oil for shafts/bushings, White lithium grease for servos, General grease for bearings [71]
• Only use petroleum oil on metal-to-metal parts, most plastic types will weaken when exposed
• When threading the ball links, plier on the link and turn the plastic link
• If servo head is not aligning horizontal as expected, turn it 180 degrees
• Mount battery with connector cables sticking out towards the rotor shaft
• Leave enought space between pinion and main gear that a piece of paper could pass through
• Don't use trim on the trail rotor pitch, confuses the gyro
• Make sure no servo linkage is binding to avoid servo tear/heat-up [72]
• Avoid binding by moving link rod a hole further in, less travel range
• The balance wire on some batteries can break, put the balance wire along-side the battery with a piece of tape [73]
• Fly a few times to break in the heli, especially the links, less twitchy
• Keep the ESC away from the gyro and possibly also the transmitter to minimize interference, 3-5 cm [74]
• Also keep the servo and gyro signal wires away from the ESC and engine power wires [75]
• Use the outter-most hole on the longest servo arm for the swash-servos, links rods perpendicular to the horn [76]
• Although ESC is pre-programmed, do the setup to make sure the throttle range matches transmitter and any problems during manufacturing [77]
• A good battery pack has the ability to hold voltage under load, some battery pack will drop voltage, resulting in bogging of head speed [78]
• Be careful when removing the battery from the velco to avoid cracking the battery mount [79]
• Most usual crash repair parts to get: main shafts, feathering spindles, blades, skids, flybar, tail belt, and ball links [80] [81] (left side, down)
• Broken engine can cause ESC to die, check all 3 engine wires using ohm-meter, great variety between each wire indicates defect engine [82]
• Always put on the ball links with the same orientation, the side with the text pointing outwards
• When adjusting link length, only do full turns, no half turns, the link head has different sides and construction
• Use 3S (series) batteries, 2S batteries doesn't have enough punch for proper headspeed
• Try 0-100-100-100 throttle in normal mode when regular hovering is problematic
• Solder Deans female connector on battery, male on speed controller
• During gyro initialization, keep the heli still and no transmitter stick input
• After extended use replace main shaft head screw, high-speed/stressed bearings, and worn-down parts
• When changing the pinion, the gyro gain will likely be lower, i.e. 16T 63%, 15T 40% [83]
• If heli moves to the left or blades are not tracking properly, try measuring the links between swash and seesaw arms, must be 100% identical
• Proper blade tracking is important, it's one of the aspects of to get absolute razor-sharp precision control in-air, the difference is huge with properly tracking carbon blades

Checklist and maintenance

1. Check mixer nuts and bolts in head and tail
2. Inspect screws and alignment of main blades, flybar, and tail blades
3. Move feathering shaft to check dampeners
4. Check all ball links for slop or play
5. Check tail belt tension
6. Fully charged batteries, both heli and radio
7. Radio range check and trim settings
8. Make sure gyro, receiver, and esc is mounted securely
9. Inspect power and servo wiring
10. Perform full cyclic throw on all servos, watch swashplate movement
11. Switch to Normal mode, Throttle-hold on, low throttle stick, then connect power
12. Start a timer to notify when the battery is depleted

Final Setup

Photo gallery of the final T-Rex 250 build with everything mounted.

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References

Builds and reviews

• Elefun T-Rex 250 review
• T-Rex 250 Super Combo Feb 2009 manual - pdf
• T-Rex 250 Combo Feb 2008 manual - pdf
• T-Rex 250 build thread - Steph280 setup
• T-Rex 250 Super Combo Review
• Changed to - Trex 250 build pics
• arky's T-Rex 250
• RC Heli magazine review march 2009
• jasmine T-Rex 250 build videos
• Jermo's DX7 Setup Video
• T-Rex 250 Build Tips
• Bob Finless White T-Rex 250 build videos - excellent

Traning

• Finless Bob's flight training videos
• Radd's school of rotary flight
• Fly3dx.com Set Manoeuvres 2009 - training videos

Other

• 7C vs DX7
• Official Align 250 product page
• Mini-HowTo - Align GP-750 Heading Lock Gyro
• The T-Rex 250 new products thread
• Align T-Rex 250 Tail Oscillations: Solved
• How to use a pitch gauge
• Helicopter Transmitter Setup - Spektrum DX7 - video
• Innstilling av Throttle og Pitch-kurven
• CCPM Helicopter Setup
• Head Lock vs Rate Gyro Mode - video
• Bob White video review and guides - HeliFreak Summary post - excellent resource
• Spektrum DX7 - Step-by-Step Bearing Mod - Bearings
• HeliFreak T-Rex 250 pics and Videos
• Which stock blades on Trex 250
• RC Helicopter Pre Flight Checklist
• FS+'s T-Rex 250 Tips - FS+'s T-Rex 250 upgrades
• "New Metal Tail Holder" or "Precision Tail Set PRO"
• Trex 250 maintenance and repair cycle