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Stickyfingers
11-12-2006, 06:51 PM
I rec'd my AON 4900 and Mamba 25A combo recently and was set on using my existing Intellect 9.6v packs but just thought I'd have a look at how much aggro it would be to fit the 11.1v 2250mah lipos I use in my T-Rex helicopter.

I have seen lipo conversions on the H8 before but they all had the motor moved over to the other side and flipped the centre diff to make room which seemed like a load of grief to me. After a little playing around I managed to fit my lipo with the motor in the original place. I also keep the aerial in the stock location and the original body fits without any modification.

In fact, when I sat down and looked at it I wondered if Kyosho made it this easy to do a lipo conversion deliberately!

The servo fits perfectly into the top mounting on the plate which as you will all know has the mounting holes already drilled. I had to move the front chassis brace as you can see but that was a matter of drilling one hole.

The only real modification was getting the Dremmel out and trimming the chassis a little and cutting down the original posts that mounted the servo plate. Other than that it looks made for it! Even the battery is held snug by the chassis lip and the servo plate posts. Theres just enough flex in the plastic where the aerial plugs in to lift the lipo up and out over the chassis lip.

Sorry to write so much but I'm well chuffed! Can't help feeling I've missed something though cos I never thought it would be this easy!

http://www.lamboreplica.co.uk/H8/H81.JPG

http://www.lamboreplica.co.uk/H8/H82.JPG

http://www.lamboreplica.co.uk/H8/H83.JPG

Migs
11-12-2006, 09:09 PM
Wow... that's pretty impressive being able to fit such a big lipo in the stock chassis without really doing much modding at all. What kind of runtime are you getting with that 2250 lipo...? I would have to guess at least 20-30 minutes. I'd be a little concerned about the weight balance but if you're just bashing it's not a big deal.

Great job...!!! :D

MrUnlimited
11-13-2006, 06:46 AM
Nice! But with the servo mounted this way you can only mount a truckbody on it.

BitHed
11-13-2006, 07:16 AM
..ahh the upside-down servo (clapping hands) well done indeed...Kinda kool seeing as i cant even see many other mods in there...Great job...

Stickyfingers
11-13-2006, 08:07 AM
Nice! But with the servo mounted this way you can only mount a truckbody on it.

?????

The stock body fits just fine. The servo sits in the central 'hump' with plenty of clearance.

Migs- not even run this setup yet. I was just seeing if it all fitted. Now I know it does I'll crack on with fitting the ESC, HS81MG, AON and new RX.

20mins will be fine if thats what I'll get :) These batts give me 15 minutes of hovering with my T-Rex and that sucks a whole lot more amps with it's 400 class motor.

erik_dedobbeleer
11-19-2006, 01:51 PM
Hi sticky... ingenious tuning,
I'd consider glueing some lead on the opposite side, with the receiver and ESC on top of the lead for a low gravity point and good balance

Erik

Stickyfingers
11-20-2006, 12:28 AM
Hi Erik

Yeah I would say you are right but I'll see how it drives. I don't race and I'm not an expert driver by any means so I'm not sure I'll even notice the balance. Obviously all things fall to earth at the same speed regardless of weight so it should still fly straight but I hear you on the handling. I guess we'll see. I'm reluctant to add weight I have to admit. Holding the car in the hand there doesn't seem to be that much imbalance. I guess the motor, ESC and RX aren't that much lighter than the lipo. Either way the whole setup has a very log CofG.

These are pics of the latest setup. The ESC has been calibrated, setup and affixed. The Rx is affixed and also the motor is finally fitted after I had a few spacing/mounting problems. I've not heard from anyone else having issues with mounting but on the 3Racing mount I had to space back the motor otherwise the RC18T pinion wouldn't line up properly. You also have to use a countersunk lower motor mounting screw otherwise it hits the gearbox.

Just got to mount the steering servo now. I bought an HS81MG but it was bigger than necessary and would have been more difficult to mount. I settled on an HS65HB which is virtually stock size and is plenty strong enough for my purposes. I have also fitted the 30T spur along with a 16T pinion and she certainly manages to balloon the tyres. As soon as the servo is mounted I'll give her a spin but I have a feeling I might need a fair bit of space!

Cheers

http://www.lamboreplica.co.uk/H8/H84.jpg

http://www.lamboreplica.co.uk/H8/H85.jpg

erik_dedobbeleer
11-20-2006, 09:12 AM
Still looking good!

testing the balance is real easy: put a little mark on the bottomside of your chassis: in the middle between 2 mountinggscrews of the gearbox, do this for front and back side. Then use a lead pensil to draw the line to the very front and end.
Put your car on a horizontal table.
(use that funny ruler with the airbubble: sorry, don't know the english word for it)
Then use chopsticks or so to lift the car and see which way* it tumbles. Retry a few times to see if it is repeatable.
(*That's the way it will turn over before landing top down if you make big air ;-) )
Note that you don't need to add much weight: just move it more outward or back inwards depending on which side your tumbling.

If you only lift the front or back, you can also fine tune the length/ preload of your shocks.

Oh, and you may want to use duct tape on the inside of the tires to stop them from Ballooning, or use foam inserts.
The added weight in the tires will cost you some acceleration but acts as a gyroscope during jumps: keeping it more stable and controlable.

Jrgunn5150
11-20-2006, 10:23 AM
Funny ruler with the airbubble is called a level in english, and great thourough explaination!

Stickyfingers
11-30-2006, 02:24 PM
All done!

I'll write a report on how well it goes once I've wiped this stoopid grin off my face!

http://www.lamboreplica.co.uk/H8/H86.jpg

Four8s
04-16-2007, 03:41 PM
Still Grinning? Howd everything pan out? Anybody else try this?

JasonH
04-18-2007, 12:06 PM
I did pretty much the same thing, but ended up using a carbon fiber chassis and top brace and flipping the motor. It was easier than trying to mount the servo upside down for me.

Mine screams! I had problems with the first receiever I was using as the range was poor (I assume it was interference from the brushless setup) but I switched to a Spektrum and it's been great. I don't know where the weak point in the drivetrain would be because I've upgraded everything and haven't had a failure yet. I'm using a Wraith 7k, Mamba 25, Micro RS4 12t pinion, a 3Racing delrin non-slipper gear, Atomic ball diffs front, rear and center, 3Racing heavy duty wheel CVDs and titanium center shafts.

The chassis I got from holeshoteng on eBay and it works great. In fact, I just ordered another one for my brushless Mini Inferno ST project. Also, I got both the lipos I'm using from royal_sharp on eBay. They're 2200mah 11.1v 15c and were under $40 each shipped. I'm using a Venom lipo balance charger and haven't had a problem.

If you or anybody have any other questions let me know.