The Super Jet Hopper 10.8V Project + Video

[SuperBandit]

Here is some pictures of a small project of mine.
I took the lower chassis, A arms, front wheels and the red body of a classic old Jet Hopper.
The car had problem with its electronics and could not run.
The rear axle (with very fast gear set), rear wheels, upper chassis, and electronics from a yellow Head's up jet Hopper. This other car came with a broken A arm and the yellow body was kept together just by glue.

I modified the position of the spare wheel in order to protect the power pack when the car tumbles upside down.

This is the result:

 

I build my own power pack with 2900 mAh cells that can last longer than the packs that are available.
And today I added an extra cell bringing the overall voltage to 10.8v 



As you can see, the extra cell is on the right hand side, while the Tamiya plug is on the left.





Below a picture of the powerpack removed from the car




And a close up of the rear from where the power plug exits the chassis



Another picture of the overall assembly



Rear View



With the extra cell the car is very fast although it is very hard to control.
My next experiment would be to add an extra cell to bring the overall voltage to 12V.
Do you think that is going to fry the electronics???

Thanks for looking,
giovanni

[tyco toys]

Nice, I did something similar using a 2  AA battery holder  ( http://media.digikey.com/photos/Memory%20Protection%20Photos/BC22AAL.jpg ) on the Tyco's that take  8 AA batteries.    1 extra cell is fine, but two extra cells will require you to buy a new motor  very soon!  The brushes in these motors are thin and don't last long at higher speeds.

[SuperBandit]

Hi ST,
thanks for the advice.
I do not know whether the holder is an option giving the limited amount of space.
I might try that on the Super Bandit where the space is not a problem under the body.

Actually, I would like to add a new motor. I know that a 380-size should be fine.
The problem is that I would not like to have one of those motors that require a lot of maintenance (i.e., changing brushes too often). Do you have any suggestions??

thanks,
giovanni 

[tyco toys]

I believe this high performance motor is the same size as the factory motor, but the end bell is longer so you'll have to come up with a custom cap to keep it in place:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAHK6&P=7


I also believe this is the factor 370 motor used in fast traxx, and other 9.6V tyco cars. It's a little faster than the older motors used in the tyco's that took  8 AA batteries:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXGLK3&P=7


You're actually not limited by motor speed, but by the current draw limit of the speed controller.  You're also limited by the weak factory gears in the gearbox, as we've all  stripped  tyco gears  without much effort.   There is even a faster motor  which I won't link here because it'll not only burn up the speed controller, but will burn itself up in no time at 9.6V, that is if the gears in your gearbox don't strip first.

A proper gear puller tool  ( http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHHN2&P=ML ) is a must  to remove the factory brass gear!

[SuperBandit]

Thanks ST for all this info.
I tried to find a micro gear puller here in the uk but with no luck.

However, I found this other motor Graupner Speed 300 6V that has 29k RPM.
A guy mounted on his Jet Hopper and goes pretty fast.
You can see more here http://masterbsax.de/english/jht.htm. More info available here http://www.tamiyaclub.com/showroom_model.asp?cid=64650&sid=20877.
The guy is still using the original gears. Only changed the electronic and servo.

I might go in the end on the same route.

Thanks again.
giovanni 

[jeffescortlx]

Awsome project and thanks for the links! Reminds me of when I was a kid. I was allways wrecking my R/C's. I fried a lot of electronics doing this kind of stuff.
I noticed your gear shifter does'nt have the normal red lever, is this what was used on the older 8 AA car's? I have a New Bright truck with with the same kind of shifter and tranny....Have any extra front bumpers you want to sell?

[chevyguyjay]

nice.   

[tyco toys]

SuperBandit,  RC  airplane guys  still uses these motors as they're still used in popular GWS planes.    Check RC airplane shops for a gear puller.     Yes the motor you linked is the one I didn't want to tell you about    It's  also sold  under the name GWS 350.   The motor is a current hog,  sucking 10-12 amps. You need a 100-150watt speed controller.  The brushes don't very long at 9.6V.  It's a bit faster than the 280BB motor I linked  above, but doesn't last nearly as long and is less efficient.  Don't even think about using these motors with the stock electronics, they'll  fry the stock speed controller in no time. 

jeffescortlx, he's actually using a gear box from a newer Tyco car.

[SuperBandit]

I'll look better for those gear puller. I think I found one on Ebay.

As for removing the rear wheels, which type of gear puller should I use? Any suggestions?

Thanks again for the info. But that is also where my limited knowledge in electronics stops.
I thought that esc limits are given my the motor turns. But you talk about amps. So, for instance a Mtroniks eco20 http://www.anticsonline.co.uk/1631_1_1949064.html I should be fine since the limit is 20 amps. Is that right??

As for the rear axle, from tyco cars up to now I have seen three types. I'll post some pics of them.
The one shown in here is the fastest in my opinion. As it is I reckon it can go faster than 27km/h. But no precise measurements yet.


giovanni

[SuperBandit]

And sorry,
no extra bumper...

[tyco toys]

20A should be plenty.    Basicly  any speed controller made for 1/8th scale RC cars, like the Mini-T   will work.     I had some posts about removing the rear wheels  on the old forum.   You'll have to custom rig something.  I would use  an automotive gear puller:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40970


I would   take a sheet of metal  and cut a circle out of it.  Then I would cut  out a rectangle from the center to the outside of the  circle so it can slide around the axel.    This picture kind of shows what I'm talking about:

http://www.instructables.com/files/deriv/FG1/RKG4/F51ZB9TW/FG1RKG4F51ZB9TW.MEDIUM.jpg

This way you can pull the wheel  using the gear puller above, but not have to worry about the gear puller  damaging the wheel.    I hope this makes sense.     Let me know if it doesn't.

[SuperBandit]

It makes perfectly sense! Thanks again for this load of info
So have you ever changed the gears from your tycos??
If yes, which one would you put in to make them more reliable?

 

[jeffescortlx]

What I have done in the past to pull a pressed on pinion gear is, slip 2 peices of metal under each back side of the gear, then use a center punch to push the motor shaft out. I make sure all the weight and pressure is on the metal plate on the back side of the gear, and that the motor it's self does'nt get any of the force to remove it. It's free and does'nt damage any thing.

[SuperBandit]

Just a small update on the body.
I mounted the bigger rear-wing of the yellow heads up as I think gives more stability.
Here are some pictures.

Let me know what you think of this set-up compared to the previous one.
thanks for looking.

[chevyguyjay]

i like it. matches the rear wheels to. need to post a video of it in action.