TEST: GTeng T910F “Flying spider”

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INTRODUCTION

Here is a new RTF 5.8G compact microquadcopter, i.e. the GTeng T901F. It’s no an nuple copy/clone of the Hubsan H107D. GTeng introduces with the T910F an original design with a lot of rectangular shapes…This model is also able to record 720p videos while broadcasting the FPV signal.. Let’s have a look to this “Flying Spider”.

BOX CONTENT

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+ 1 x GTeng T901F (with a 1S 500mAh LiPo with microLOSI)
+ 1 x Transmitter (using a 1S 500mAh LiPo with microLOSI included)
+ 2 x USB charging cable with microLOSI connector
+ 4 x Spare props (2 CW, 2 CCW)
+ 1 x MicroSD card reader
+ 1 x 4GB microSD card
+ 1 x Screwdriver
+ 1 x Instruction manual (English)

OVERVIEW

The general design is original with L-shaped arms.After the first contact, you can notice than the T901F seems pretty light. The plastic material is flexible… a good choice to absorbe energy spread during crashes. Out of the box, the T901F comes with the propguard installed. They are ultra easy to install/remove: only 3 clip points.

-Front view

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With the antenna mod

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-Side view

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-Rear view

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Without the battery inserted

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and with ….

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no real free room available

-Upper view

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-Bottom view

Blue LEDS on front, white on rear…. strong enought for night flights but hard to keep orientation with so closed colors.

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The microSD slot to insert the 4GB card

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The simple 5.8G linear antenna

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As we will see directly soldered on the camera-FPV PCB

-Weight

Prop guard are IMHO too thin versus the length of each branch. By consequence the wil lbreak fast versus time. In another hand, they are super easy to install and remove ….

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Less than 65g with the battery

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Motors

Strong 8.5x20mm coreless mortors are installed

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LiPo

A 1S 500mAh LiPo with microLOSI. No discharge rate mentioned but the should be at least 20-25C coz the other 500mAh LiPo for the transmitter is much more lighter & compact.

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Camera-FPV module

The lens size is very narrow. Here a M5.5 lens mount format… We can be afraid about the light sensitivity of the camera module

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I hope that a M5.5 wider lens will be sold soon (t could be possible since I found a model and asked to BG to stock it …. so wait & see)

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Unfortunatly, the camera lens sensor is directly solderd on the PCB… We can’t install any 808#16 lens D sensor instead (the usual trick)

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Disassembling

Disassembling the machine is simple ….

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Look the 4 wires to be guided into each arms… You have to avoid during reassembling to domage them during the reclipsing process and/or during the rescrewing session.

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We can guess the clock quartz associated with the RFchip, here a simple XN297 …

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Antenna is well tuned to 31mm … If you are here…. do the antenna mod by drilling a small hole through the plastic upper canopy part.

Transmitter

An original gamepad style with a builtin 4.3FPV screen. No sunshade here….. The default brightness setting is ok but not yet enought to flight strong daylights.. Good news, here “whitesnow” signonym of FPV friendly monitor. When you will loose your FPV connexion, no blue/black screen.

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From left to right buttons: FPV screen power, camera trigger, photo trigger, brightness – and brightness +. I found that the brightness buttons were innefficient…. or I didn’t noticed the brightness variation. If you click on the left stick, you should cycle between 3 speed modes. Unfortunatly with my model at least, no beed emitted and I didn’t notice any different behaviour when I played with this click… Maybe my radio is not fully working (To be confirmed with othe owner’s feedbacks). If your click on the right stick, here you can engange a flip after giving the direction indication. Two rear buttons can be found on the right side. The most external engages the headless (LEDs flashing slowly) and the more inner one engages RTH . Finally to calibrate accelero, you have to push stick in lower outter direction. To calibrate/set the head course for the headless mode, you have to push both stick in lower-inner directions.

Other good news, the TX is powered by its own provided LiPo, another 500mAh LiPo but with probably a lower discharge rate.

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With this one you have 15-20min of duration… You can save more if you don’t power the FPV screen

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A XN297 is here …. Unfortunatly, I was not able to bind the T901F with any other existing T901F… so another YaP… 🙁

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No PA+LNA stage with the XN297. Don’t expect a gread radio range…. 40-50m out of the box, around 100m with the antenna mod.

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The 5.8G antenna is a half-plan one … directly taped on the metallic structure… not sure it’s the best situation. No DIP switch to select the freq. By default, the Vfreq is set to E4=5645Mhz in NTSC format.

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The coaxial cable directly soldered on the VRX. A first would consist to insstall a uFL/IPX connector here… then install a real coax with a standard SMA/RP-SMA.

FIRST USAGE

As you can see the T901F is strong and stable thanks to its 8.5mmx20mm motors and large props. Here no real problem to carry the 7-9g of the FPV system. I noticed with my radio, I was not able to change the speed mode… so I was blocked probably in the intermediate mode which offer a good yaw rate and already some good pitch & roll rates… The T901F offers good vertical thrust… you don’t feel it as an heavy machine. It’s nimble and agile. Out of the box the control range is about 40-50m without antenna mod. The flying duration is around 6min (7min if you push a bit). Be aware, after LVC alarms, you have just a couple of seconds of extra flight time…

I was really suprized by the 720p recordings… color rendition is pretty good, frame rate ok too (30fps)…. Of course, the FOV is limited to 70 degrees… no miracle with such pinhole lens. When you are recording, you can observe a frame rate drop in the FPV live signal to 20fps approximatively.

CONCLUSIONS

The T901F is pretty close to be one of the best 5.8G microquadcopters. What are missing ? a wider FOV for sure …. and maybe/probably a longer range control out of the box w/ the antenna mod, this second point is less critical)… but except that, all other ingredients are here. Superb 720p recording, strong FPV signal, good flight duration & stable machine… This machine can be considered as good H107D competitor…

UNBOXING

PROS

+ Stable machine
+ Nice color rendition & precize 720p recordings
+ Jellofree
+ Lightweight
+ Solid FPV signal within 100m (E4=5645Mhz in NTSC format)
+ No blackscreen
+ Lightweight TX+FPV screen radio
+ 6-7min of flight time
+ TX battery
+ Propguard easy to insert/remove
+ Good faisafe (1,5s before motor to stop)

CONS

– Frame rate drop when recording is turned on
– Narrow FOV associated with the M5.5
– Control range limited to 40-50m (w/o antenna mod)
– Reassembling a bit tricky to guide all wires into arms
– No speed mode selection ? (with my model at least)
– Brightness buttons not working ?
– Solidity of propguard and at arm/canopy jonction ?
– YaP (Yet another Protocol)

RCgroups review thread: http://www.rcgroups.com/forums/showthread.php?t=2646793

This quadcopter have been courtesy provided by Banggood in order to make a fair and not biased review. I would like to thank them for this attitude.
You can find it actually for 99USD at http://www.banggood.com/Guiteng-T901F-5_8G-FPV-With-2MP-720P-Camera-4CH-6Axis-Headless-Mode-RC-Quadcopter-RTF-p-1041987.html

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