Sunday, November 20, 2011

1/10 Losi comp crawler avec LED

équipement de la machine:
- Ballistic Crawler Brushless Motor 18.5T (avec senseur de position rotor)
- pinion 14 dents
- contrôleur: Castle Creations mamba max pro (prise pour senseur, programmable)
- batterie 11.1V 1350mAh 3S 30C LiPo
- Connecteurs Traxxas (soldered on battery)
- Castle Creations 7 Amperes Adjustable BEC (recommandé pour les servos a torque important)
servo: power HD 1501(engrenages en acier) - torque= (5.5v?)

- LED Light Set fait maison: led white 25000 mcd sous 20mA +4 * 100 ohm resistances= 0.6 € / u
dans un support en plastique récupération de consommables de laboratoire.
- peinture Pourpre métallisée. les traces de flamme de l'avant sont en peinture antirouille pour metaux. malheureusement le solvant de pulverisation du pourpre a légèrement modifié l'allure des lignes grises...

 DIG servo: multiplex MPX tiny-S : and  0,06sec/60°  pour 19g

-commande de servo DIG analogique avec un interrupteur bipolaire 3 position stables : contact milieu-gauche/ pas de contact / contact milieu-droite correspondant à : dig Avant / pas de dig / dig Arrière.
les potentiomètres ajustables (gros de 1.7kohm, et 2x 2.2kohm petit pour réglage fin) permettent de couvrir une plage largement suffisante pour d'autres applications a multiples positions de servo (initialement pour declencher un appareil photo).
plan de câblage des switch a relier dans l'émetteur radio à un des canaux :

video du premier test:


Nouvelle configuration des poids dans les roues grâce à de la soudure (40Sn-60Pb) enroulée autour des jantes des roues et fixée avec de l'adhésif : 
Avant: +200g / roue
Arrière: +100g / roue
j ai déjà pu remarquer des améliorations du comportement, notamment un passage facilité là où les roues arrière restaient bloquées lors de l'escalade de rochers. La traction sur les roues avant est probablement plus importante avec 200g dans chague roue.

****commentaire sur amazon****

The title does not mention if the cvd's are updated but if it breaks the SN can be sent to LOSI to get an exchange if it s the old ones. i haven t had any issues so far.
The dig servo can be easily controled with an old remote with 3 channels min., just assemble 3 adjustable potentiometers in serie (2x 1.7kohm + 2.2kohm), shunt the 2 at the extremities with a 2x 2 contacts lockable in 3 positions (contact left - no contact - contact right) switch. use the central potentiometer to adjust the neutral which is connected to the centre wire of your channel plug. You then get either front or rear dig in action - it works great for me - fully "programmable".

Add weight in the wheels: i taped soldering wire (40Sn-60Pb) inside the wheels as it is the cheapest i could find. Losi s manual recommands 175g in the front weels and 75g in the rear wheels. i had to cut some of the foam inserts with a cutter.
strangefully the foams are not the same on left and right wheels (????) upon removal from the tyre, one came back to original shape quite fast and the other did not.

i use castle MMP esc with Novak brushless 18.5T sensored motor successfully contrary to what can be read on the forums - it is compatible without interference :) i use the 15° (????) material timing but needs improvement. an external BEC is recommanded as the MMP only delivers 3 A current to the servo (fragile).

- Battery, Play time: (18.5T brushless, 14T pinion) steep place - flat place with rocks.

2000 mAh Lipo 2S (maxamp) : 54 min - 1h10
1350 mAh Lipo 3S (losi):  50 min (40 min) - 1h05
(good to have 2 batteries when far away from home on a hike)

radio Transmitter: 8 x nimh 2450mAh duracell  => way more than 10h.

-base protection: i wrapped some pvc plastic from a soda bottle around the chassis tubings to easily slide on rocks and avoid damaging the nice looking tubes.

-it is recommanded to drill a hole in the worm gear box to allow inserting grease with a syringe and small needle every 2-3 runs so it stays well lubrified (heats up a lot).

- installation of Losi Non-Slipper Top Shaft Gear

"If you use a LCC then you'll need this gear. One of the biggest problems with the LCC if you run good 2.2 tires that really dig into the rock is the stock slipper letting go. This gear replaces the slipper clutches so there's no more slip if your in to really hard crawling this will be the first thing you should replace"

-most of the high torque servos have 25 teeth head. the package only contains Al servo arms for 23 and 24 teeth servos!
-funny tyre foam (see above)
-grease tends to be ejected from rear worm gear box by the driving axle hole.

options not tried yet:

-HD worm gears
-some people even cut into the chassis and remove parts of it to lower the GC.

-----------------------------a faire---------------------
-HD worm gears
chauffe moins et est avec un rapport final de vitesse plus long que les pinions originaux. a ce qu 'il parait, il se peut que le pinion pour la partie avant soit mal usiné, il faut le limer un peu.


... Just finished eliminating some unecessary weight from the frame. As you can see from pics I dremeled out the cross braces on the frame, the front mounting ears for the front elect. tray, and the top middle frame brace on the motor side which I felt was not needed for support. I also eliminated the long frame stiffeners and moved the short ones from the shock mounting holes, which I thought slowed the process of changing locations quickly, to the top shock pivot location. This made it easier to change shock location, and lowered the cog of the stiffeners!! You never have to move them for any adjustment and now you dont have to hold a nut to loosen for shock arm position!! I also in eliminating the electr. trays and repositioning the battery on the upper links as well as the receiver and bec on the upper links in back on a thin piece of lexan from a body, in total with everything done, got rid of a total of 2.2oz from the LCC all of which were at or above the vehicles COG. It made a big difference on inclines and side crawls.

fixing hpi wheely king: steel tranny gear, HD bevel gears and shafts. & Wheely king snow plower

hpi s plastic transmission gear set (18€ or 13$) are not suitable for use with powerfull brushless motor systems. read below to rectify this issue with a relatively small budget.

this would be unnecessary if only RC4WD had not discontinued their steel hardened gears!
thanks to "Snoopmax" for the online informations provided about the gear sizes available.

1) 15Tooth Mod1 5mm shaft gear. (available for other rc cars) (30 € in france, 10 $ in usa)
2) 22Tooth Mod1 5mm shaft gear. (available for other rc cars)
- find a 5mm shaft to attach the 22 tooth gear on. be carefull to cut it to the most appropriate lenght. i cut it too short and place some common small 5mm hollow metal discs on both sides to adjust the position of the gear with the other gears of the tranny.

This setup uses the 28 tooth original plastic gear which seem not to suffer too much so far.

3) the 28 tooth plastic gear in the bottom could last longer but i am preparing a home made metal version of it in soft steel from a random stick:
-make the shape of the metal very roughly round with a saw and tough file and dig a 6 mm hole in the centre with an exact 90° angle shaft drill system.
-screw it tightly onto a screw bolt (as shaft) and attach it onto the vertical immobile drilling system. I rotated the drill-fixed-metal-gear applying pressure on the edges with a hard file. The file being immobilised in such a way it applies pressure on the metal being circlized. This lasts hours before the circle comes to perfection. This way you make sure it is perfectly circular instead of elliptic if you were holding the file by hand.
-once the filed up "gear" has the appropriate size, dismantle the round piece of soft metal and glue a paper printed real scale picture of the original gear (you can find on hpi website as a pdf manual) on the metal round shape just done taking care of the alignment. carefully cut the paper to the exact shape of the gear.
- use a hand metal hard saw to drill the teeth of the gear in to approximate shape taking care not to dig too deep.
- use a small handy driller with a small grindstone attached to it. Grind the tooth to perfection very slowly so you don t do mistakes.

BE PATIENT. This process takes hours of work.

4) i purshased the 48p 96 tooth spur gear and a 15 tooth 48p pinion gear from HPI and it was a bad idea. with the high power 7700kv brushless motor i have, the carbon fiber spur gear got destroyed in 15 min. i adapt a KIMBROUGH 32P SPUR 64T and a 15 T 32p pinion instead for durabilty. you only need to drill 2x 3mm holes in the plastic to fit it onto the hpi original spur holder.

the next gear problem: the bevel gear in the rear differential broke after 2 months of fun, wheelies, etc.
i believe this is another clicking sydrome of the wheely king.
- will be fixed by heavy duty bevel gears (18$)

quick sum: 140$ WK + 30$ steel trany gears + 18$ *2 bevel gears + 20$ tranny gears (plastic, bad choice) + 20$ new servo saver kit = 246$ total cost so far in 2 months.

what s next? any other low endurant gears hidden on the hpi wheely king?
EDIT: 10-9-2010
i had to replace the aluminium differencial gears with heavy duty steel gears from Integy. i had also to buy their shafts, because the original hpi shafts they are not compatible with the steel gears. well i am very disappointed as it broke on the 2 use, all the 4 new shafts giving power to the wheels. i spent more than 50 $ on brand new shafts. what a waste. thank you Integy, you seel very bad material or is it only made for slow users?
here is the reference not to buy: Universal Drive Shaft (2) for HPI Wheely King (use with #T8126)
i will try to adapt my original shafts to the integy heavy duty bevel gears ( really HD ?)HD Bevel Gear Set for Wheely King (use with #T8118)

picture: broken integy shaft parts T8118. broke in crawler gearbox mode. the 3 others shafts broke soon after with the 7700 kv motor installed after 3 minutes use. i did not even do a burnout ...disappointing...

EDIT : 19 -9-2010
broken again. nevermind, let's fix it!
i tried to recover the integy shafts but it was not a great success as the longer metal stick transmitting power to the wheel axis became "wobely" as shown below.

back to the original shafts modification to be working with the bevel gears from integy. i drilled a 2 mm holes carefuly enough making sure the holes do not look like a funnel, otherwise the metal stick would never hold. NB: hit the centre of the small metal stick with a hammer to slightly alter it so it stays in position in the shaft. do not hit too hard as hardened steel breaks (i tested for you, thank god i wear glasses!) final assembly of the original shafts modified.

EDIT: 23-4-2011
I have experienced some trouble with the adaptated shafts from HPI and INTEGY. I thought that it would be stupid to buy the same material again that would break after a short period of use. so I had this idea of using a standart Inox/stainless steel screw and to modify it so that it would be able to enter the space of the original shafts (cost 0.2 €). just have a look at the picture below. it is very simple you just have to cut/adjust the head of the screw into a "T"and to alter the diameter of the shaft from 6-7 mm to 5 mm in order to allow the ball bearing to be inserted into the shaft. when that is done, one just has to drill a 2 mm hole at the tip of the shaft so that the little 2 millimetre bar would fit into the INTEGY "HD" bevel gears and transmit the torque to the wheels of the car. be careful when you drill the hole for the little bar because if it is not perfectly in the centre of the shaft you will experience tremendous problems to insert the device into the Bevel gear.
IT works !


i adaptated a piece of aluminium and a 17 servo to my rear transmission axle to control the direction there too. see picture. My wheely king has 4 direction wheels and 4 wheel drive :) see the video for some fun twists! NB: avoid to turn only with the rear direction while at high speed, it does not forgive!

Edit: 1/5/2011

temporary fix of the small bevel gear:

shortening the small gear in order to shift it s position in the bevel gear box.

BIG DISCOVERY: one of the ball bearing of the small bevel gear was broken and it was the reason for the gears to brake because it induced a misalignment of the teeth when a force was applied. i wish i had seen it before i have to buy another set of HD bevel gears.

the guilty

jumps and passing on Chiara


Wheely king
7700kv - CC MMP
15T pinion
stock HPI bevel gears (HD bevel gears from integy don t like fast brushless)
integy transmission mobile trees
homemade shafts (from steel screws)
5000mAh lipo 20C
hardened steel trany gears (forget about plastic gears)
4 wheel direction
2 servo
Super short turning radius!
so far the only thing i know will break for sure are the bevel gears, i have another spare pair, lucky it s not too expensive!

*********NEW 11/2011***********
Wheely king as a snow plower!

a toy for those that like to stay warm inside...

i know the lesft side is protruding more by 1cm ish, initially a mistake from my measures, it might be a good thing to optimise the equilibrium of the machine. the snow is being pushed to the right side of the plower shovel and therefore the amount of now accumulates more on the right side (shorter shovel).

Test of the prototype in real conditions soon...