Sunday, August 30, 2020

Notes on the JBL Cheetah 11101 (truck) and 21101 (buggy)

 These are hobby / basher grade 4WD cars.  They are a step up from toy-grade cars like the WLToys lineup, built and priced accordingly.  They are not the toughest cars ever but are (reportedly) pretty decent.

(It should be noted that crashing any car from great heights onto concrete is likely to break it.  This is true even of high-end expensive models. )

Basic specs:

  • 1/10 scale, 4WD
  • 515mm long
  • 3S, 4000 mAh battery, T-connector (a.k.a Deans), 15min
  • 3670-2500 kv motor.
  • 80A (80 km/h) or 120A Hobbywing ESC (100 km/h)
  • All-metal gears.
  • Part-metal chassis.
  • Oil-filled dual-rate (progressive) shocks.
  • 17mm wheel hex
  • 135 / 145mm diameter / 75mm wide tires w/foam
  • LED lights 

 Note: This car is NOT a rebadged Vikar Bison or DHK Zombie.

User manual:  RCGroups 1, RCGroups 2

Transmitter:  120A versions: KTH-91900G [Manual:  RCGroups]

 

Model differences:

Car (21101):  This model is technically the "21101", though most refer to it as a "Cheetah".  Has rear wing and different wheelie bar.  Most find the wing/bar break off easily on bad landings.  Dirt/pavement combo tires.  Car is sometimes available in a package with two batteries.

Truck / truggy (11101):  No wing, "inverted" wheelie bar that tends to not break (as easily).  Sand tires that reportedly don't do quite as well on pavement.  Old models had substandard wheel nuts that could come off, but newer ones (since mid-2017) don't.  Review, review 2.

Changing from car-> truck (or vice versa) involves changing not only the shell, but the mounts for the shell, as well as the rear wheelie bar. 


Model similarities:

-  All models are available in with 80A or 120A ESC.  The 80A is often called "original" or "version 1".  The 120A is sometimes called the "upgrade" version, "version 2" or "Extreme".

-  Most parts are common between the "old" 21101 car, the "new" 21101 car, and the 11101 truck.


Related models:

-  J3SPEED : Street / on-road tires, new controller, metal slipper mount.  Also 120A with 3670-3200kv (36*70mm) motor, so faster.  Drive axles may be thinner. (Review, Discussion thread)

 

Year-on-year differences:

  • 80A models had Flysky controller (4xAA) with throttle limiting.  120A models have different controller without throttle limiting.  It may be possible to bind a Flysky GT3C (with limiting) to the later models.
  • Original 11101 trucks had different wheel nuts that tended to spin off.  These were changed to the same 10mm hex nuts as used on the 21101 car.
  • Drive shafts (CVDs) were thin / weak, were upgraded around Q1 2018.


Known issues:

  • 80A ESC and steering servo are NOT waterproof. (experiences in snow are mixed)
  • 120A might be waterproof, but might also be just "splash-proof".
  • Check all screws BEFORE running for first time.
  • 21101 wing / wheelie bar breaks easily.
  • Tires may become unglued due to high available torque.
  • Drive shafts (dogbones) tend to bend.  Easy to upgrade. 
  • Some screws are threaded into metal parts and will back out over time.  Use Loctite.
  • Wheels are difficult to remove, especially the first time.  Heating with a hair dryer seems to help.
  • All screws METRIC, most screws are hex head (i.e. allen keys)
  • Differential output cups weak.


 Known non-issues:

  • "Crackling" sound from rear at low speeds - this is normal behavior for the brushless motor.
  • Transmitter range sometimes isn't the best.  Video to help fix
  • It is definitely possible to destroy the car in stock form.

 

Parts and upgrade info

Many upgrade parts are available (JLB, Aliexpress, Aliexpress 2, Banggood, MonkeyHobby).

General:

  • It is possible to upgrade to 4S batteries, but beware of exploding tires.  
  • You also risk damaging your transmissions, especially the front gearbox.
  • Most people say the surest way to break parts is to run 4S.

Motor:

  • Stock: JLB 3670-2500kv (Banggood)
  • Upgrade: Racerstar 4068 brushless motor 2650 kv
  • Motor heatsinks: Heat sinks for 530 or 540 motor size appear to work
  • Motor fan: Banggood (picture), Video

ESC:

  • 80A (upgrade to original 80A, downgrade from original 120A): Gearbest , Banggood
  • 120A:
  • Note: people have tried spraying CorrosionX into the receiver and ESC to add a bit of waterproofing.  The effectiveness is unclear.

Servo:

  • 10kg (or more) servo recommended
  • Upgrade: 
  • Some users report the Futaba S3003 works fine, even though it is "weak"
  • Some people report the TowerPro MG995 works fine (video)
  • Note: some report all-metal steering improves the turning angle over the stock plastic parts.

Steering:

  • Metal upgrade (Banggood, Aliexpress)
  •  Note: some report all-metal steering improves the turning angle over the stock plastic parts.

Wheels/Tires:

  • Pro-Line Badlands 3.8 wheels/tires do fit. (Pro-Line)
  • Can use 1/8 tires with 17mm hex (i.e. GoolRC)
  • BSR Berserker 1/8 wheels fit.   (Hobbyking)
  • ZD Racing 1/8 wheels with 17mm hex should fit (unconfirmed).  (Banggood
  • Wheel nuts are M10.

Wheel bearings:

  • Wheel hub bearings 10x15x4mm. 

Battery:

  • 3S 4000 mAh
  • Length: with spacer foam 138mm, without 148mm.
  • Tray is 49mm wide (some say 51mm)
  • Height limited by body shell.
  • 260g

Pinion:

  • Pinion must be 32 pitch!
  • Stock: 15T: Aliexpress
  • 13T: Aliexpress (13T, 14T, 15T)
  • 17T fits.
  • 18T is reportedly too large, it interferes with one of the motor mount screws.  Can be made to fit with appropriate grinding.

Spur gear:

  • Stock: 52T
  • No known upgrades

Shocks:

  • Stock oil is likely 400 wt
  • People report good success with 800 wt
  • Note: weights in the range of 15-70 are "non-standard" USA weights.  Weights in the 200-800 range are the same oils rated using "standard" weight ratings.

CVD:

  • Reported as:
    • Original: 8mm
    • Second: 6mm
    • "Upgrade": 10mm 
  • "New", "upgraded" version (reportedly): Banggood
    • Note: these were upgraded back in 2018, photos may not be correct.  
  • There is reportedly a "hardened" version (as of 2019), but this is unconfirmed.

Slipper clutch:

  • Metal upgrade: Banggood
  • Note: it is not typically necessary to adjust the slipper. 

No comments:

Post a Comment