highflyer101

I could use some advice, and I figure you all will probably be the right people to ask. I'm trying to come up with a good configuration for a Mini Quake to compete in an obstacle course race. Here are some details...

Approx 200ft long dirt track obstacles course. Includes slalom, see-saw balance (1.5 ft wide x 8 ft long), bowling ball push (on a level track), and 12 foot water pool that must be crossed. (See picture for details)

I think that most people will be using 1/10 scale, but I think it would be awesome to get a mini out there and compete.

One of the main factors in the race is that the vehicle must be able to get through the water... so I need to waterproof it, make it float, and somehow propel it...

I read that brushed motors can get wet and that the proper break in procedure is to submerge them. I don't know what the story is about brushless.

I know I need some torque to push a bowling ball.

Right now I am considering the following....

A brushed configuration:
Graupner Rocket 400 Motor
Quantum Runner Waterproof ESC
United RC X23 6-Cell GP1100 pack

A brushless Configuration:
Golden Horizons Air Power 3600 Motor
Mamba 25 ESC (Supposedly waterproof)
United RC X23 6-Cell GP1100 pack -OR- lipo?

I really don't know how much speed/torque difference there will be between the setups. Maybe some of you with experience can provide some insight.

The main reason I am considering the Mini Quake is because of it's handling, durability, and 4wd. I hope that it can compete with the 1/10 scale trucks with the proper setup. I think people will probably laugh and underestimate it and I'd like to suprise them.

Thanks in advance!

-Inverted-

The mini Quake won't have enough Torque to push a bowling ball. I would reccomend an E-maxx in this situation.

hands without shadows

Its a level track though, if the track is hard he should be able to push it.

highflyer101

I was wondering about the bowling ball part... Supposedly it'll be on a metal track that is level, so it shouldn't take much to get it going. I imagine the MQ could make it but it may be a little slower than the larger vehicles.

The maximum dimensions allowed are 14" wide x 24" long x 18" high. I think the e-maxx exceeds that width.

Can you give suggestions on how to get the most out of the MQ? Is brushless worth the extra cost?

BRUSHLESS BASHER

You should use paddle tires to get across the pond, and a brushless motor that has a higher kv rating, like a mamba 6800, and high gears, which should make it go alot better, and make it float by the bumpers, it should also have a metal brace around the front bumper to push the bowling ball.

But I would go with a MLST, lock the diffs, put paddle tires, and bassically all of the other stuff from the MQ, but have 2 mambas, 2escs and 2 recievers with the same crystals, 2 motors will make twice the tourque, so you can gear it lower and go faster. you should also run 2 good 3cell lipos, it would be uncontrollabely fast and it wouls be able to push the bowling ball at like 60 miles an hour, and if you ges some good 2.2" paddles the wheel speed at full throttle would be plenty enough to get across the pool.

-Inverted-

1. Mamba + Mini Quake = Bad Idea

2. You don't need 2 receivers to run dual brushless systems, you just use a Y servo cable.


3. The mini-lst will not hit 60mph by any means, more like 40mph.

highflyer101

I thought about the MLST, but I don't want to spend the extra $$$. A brushless MQ would be pushing the budget anyway. As far as the paddle tires go. I thought that could be a good idea too. My other idea for that was to mount little metal pieces to the rim to work as paddles. One part of the track is "slick track". It's basically a piece of plastic with soap water on it in a U-turn. I think the paddle tires may lose traction there.

One of the main things I'd like to know if it is worth the extra $$$ to go brushless in a MQ for this contest.

hemiblas

If someone out there runs an emaxx then you are in trouble. Check out my mini quake thread with the mamba max and air power 4700 setup. It runs really nice. I dont think I could get enough grip to push anything though, but it flies. If you are serious though, you should lock the front and rear differentials. Right now the 4wd has 2wd with one tire turning in the front and one in the back. If you super glue the inside carriers together and get all 4 tires turning at the same time it will be a huge advantage. Just like the people that run lockers on their jeeps same concept.

highflyer101

That's good info on the 4wd. Are all rc 4wd trucks like that? Having all 4 wheels turning will help a lot when treading water! If I am super-gluing parts together in the gear housing I probably ought to buy some spares. Do you know the exact part I need to glue?

Luckily, the e-maxx is too large for the competition. It's over 16" wide, and the max width is 14".

carmatic1

glue the spider gears which spin inside the the differential gear itself

brushless motors are impervious to water, i think, the important thing is to seal up your esc, receiver and servo and especially the battery...put the battery and receiver in baloons

have you considered a [link=http://www.woot.com/Blog/BlogEntry.aspx?BlogEntryId=796]nikko landshark[/link] ? out of the box its already amphibious and its within the size limits, its a tracked vehicle so it should have no grip problems.... the steering is done electronically so if you buy a pair of hobby grade motors and esc's , a mixer, and the rest of the normal stuff, all you need to do is cut off some internal parts that used to hold the stock electronics, and you have a pretty unique vehicle... ive done it myself, you have to make sure you buy high turn, cool running motors otherwise you might melt the gearbox
but enough OT ... see if you can buy those tubes that the boat guys use to make sure that their boats dont sink?

banx

this comeptition sounds like it could be alot of fun, for locking your gear diff just put a dab of hot glue on the 4 small gears inside your diff. there are 540 motor mounts available for the quake, you could always try one of those...............is brushless worth the cost? well if you plan on using the truck after the comp, yes. A good brushed motor and esc will cost about the same anyways. and if your going brushless you could slap 11 volts into the motor. which means that if you are lucky enough to find traction, you should be able to push the bowling ball. i recommend getting the quake SE and not the regular one. comes with ball diffs and cvd's. also, there are some durability issues you will have to address with the knuckles aswell. good luck man

heres a link to the diff

http://www2.towerhobbies.com/cgi-bin...?&I=LXJAD1&P=7

hemiblas

Yep all good advice. Get the SE quake for sure. the standard one busts the plastic diffs with a brushless setup. I havent changed over the front end yet on my MQ and it busts parts like crazy. I put the CVDs in the rear and havent had one problem yet. If you want to do it on a budget the VR3 motor runs pretty fast in my MQ SE. If you gear it for torque you may not have a problem. I havent tried racing my brushless setup vs the VR3 motor setup but both are pretty fast. Locking the spider gears and the VR3 motor might be the ticket. Oh ya I run a duratrax sprint speed control on my Vr3 setup. You can get them on ebay for like 15 bucks cause they suck for 1/10th scale but in these minis it doesnt even get warm and it fits in the stock location of the mini speed control.

highflyer101

Thanks guys... this is good stuff.

The nikko landshark would be sweet... although one of the rules is that we can't buy a pre-made amphibious vehicle.

I'll go with the MQ SE for sure.

Thanks for the link to the gear diff... i'll probably buy a second and glue that one together for locked diffs.

I'm still torn between the VR3 and the GH3600. The cost for motor and ESC is like $80 different. If I knew that I would get a lot more torque and speed I wouldn't care, but if they are close it might not be worth that much... plus... I could always buy a spare brushed motor so if I mess one up in the water I could replace it... but I can't afford a spare brusless. :P

highflyer101

hemiblas, Does your vr3 run hot? And what gearing are you using? I was considering 13/45 for more low end power. Also, what batt are you using? Thanks!

hemiblas

I'm using 16/45 for my gearing. I havent had a chance to get it running much yet as its winter, but so far when its 50 deg outside I dont have any problems. Out here in vegas the true test is when its 110 outside but I havent had a chance to try that yet. I did get the 5 dollar duratrax heat sink for the motor and seems to work well. as the the battery I'm using the 2000mah lipo from commonsenserc. I got 2 for 39 bucks of the 7.4v version. They are only 8c but work just fine with no problems. its half the weight of the 1200mah duratrax battery and runs a lot longer. I would prob gear my truck 13/45 but I wont do it until it starts to overheat. The light lipo vs the heavy duratrax battery and heat sink on the motor might keep it from getting hot. Putting it in the mud though for sure gear 13/45. Even with 16t gearing it spins all 4 tires on my tile floor with no problem.
If you do the air power get the 4700. stormerhobbies has them for 40 bucks plus 6 shipping. You should stick to 7.2 or 7.4v. I had to completely modify my insides to get the 11.1v lipo to fit. If you check my gallery I posted pictures.

hemiblas

I was thinking of going with a speed 400 graupner motor. the 6v version or the rocket one. It might outdo the vr3, but I havent gotton it yet to test. I am going to test in next month or so once I get around to putting in an order for one. graupner also makes a 380 long can motor which would have tons of torque.
http://www.hobby-lobby.com/speed400.htm

The long can motor puts out some serious watts and might be just what you need. Not sure if it will fit with stock servo though.

Keep in mind that my brushless version smokes my vr3 motor but thats at 11.1v vs 7.4. If I put 7.4 on the air power 4700 it would probably be pretty close. I have the air power geared at 13/45 and I know I can go much higher but havent found the need for more speed with the 11.1v lipo.

hands without shadows

I woudnt go brushless or lipo on this........Just mod in a 35 turn lathe motor or a regular high turn motor and maybe a 7 cell. If the water isnt too deep I wouldnt try to make it float either, just completely waterproof it and get a nice long antenna and drive right over the bottom. If you are going to waterproof add flotation to both bumpers and secure them, and go with some high thread tires. If you use paddle tires theres no way your pushing that bowling ball, with high tread tires you will and you should be capable in water, but not nearly as good as paddles. If you want a balance maybe some paddles in the front wouldnt be bad? A lathe motor or regular high turn motor doesnt need to be waterproofed and is slow but has tons of torque, using lipo in water seems stupid in me so stick with a regular pack. I think that if you mess up on this track it will be because you are going to fast, so I think you should apply the K.I.S.S. principle.

I think the best vehicle for this challenge would be a rock crawler running a 25-40 turn motor and an 8 cell pack.

highflyer101

hemiblas:
Thanks for the tips! I didn't realize you had 2 MQ's. I checked out your gallery... very nice! I was interested to hear your comparison on the VR3 with the GH4700 on 7.4V. If they are the same, I better stick with the cheaper option. Maybe I'll even buy a second to be safe. I hear that the MQ is much faster with lipos than with dry cells. (http://www.ultimaterc.com/forums/arc...p?t-40761.html) Do you use a low voltage cuttoff, or just time it?

hands without shadows:
I think you are right that too fast on this track is bad. I also understand your skeptisim about the lipos and water since they don't mix. :P If I go lipo I will put the battery in a few balloons for sure to make sure to keep them dry. I think you are totally right that something like a TLT-1 would be the best choice, but I am really trying to come with something unexpected. Each year at work we have one of these competitions, and I won the last 2 years in a row. I am kinda expected to raise the bar or show off or something.

If I had to make a choice now, I would go with the VR3, 13/45 gearing, and the 2S2000 8C batt from commonsenserc. As for the speed control, I still like the AI Quantum Runner because it's waterproof.... although it's out of stock at tower right now.

If you guys want to check out the competitions from the last 2 years... check out these vids of what I made:

2005 - r/c blimp that can retrieve ping pong balls:
[link=http://www.mike88.net/chris/myvids/blimp.wmv]http://www.mike88.net/chris/myvids/blimp.wmv[/link]

2006 - r/c boat that can pick up fishing bobbers:
[link=http://www.mike88.net/chris/myvids/boat.wmv]http://www.mike88.net/chris/myvids/boat.wmv[/link]

carmatic1

you can use http://www.foambymail.com/Polyethylene.html as bumper-floats, just gotta cut it up to size ... also maybe they can replace the foams in the tyres... good luck with your floating mini quake , looks like you made a good choice seeing that duratrax makes mini-t wheel adaptors for it, so it opens up a whole lot of choices for your tires

highflyer101

carmatic1:

That foam is perfect! Thanks! I will probably put a thin sheet on the entire bottom, and then buy the cylinders for the front and sides. My only other thought was to buy a boogie-board and cut it up.

For the wheels... I think I will buy the wheels from the MQ RTR and put them on the MQ SE. Then I will buy a thin sheet of aluminum and cut out peices, put an L bend in them and glue them to the spokes of the rim. That way I have "paddle tires" that still have good traction.

carmatic1

actually, there are these:

http://www2.towerhobbies.com/cgi-bin...?&I=LXJRV9&P=M
http://www.killerhobbies.com/items/t...165-detail.htm
http://www.killerhobbies.com/items/t...150-detail.htm

::edit:: oh heheh yeah, i get it now, paddles off the sides of the tires, not on the tires themselves... heheh silly me but there you go, paddle tires for the mini quake anyway!

hands without shadows

I didnt realize that you were familiar with rc.........sorry for treating you like a noob there.

Lipo will be fine if you know what our doing and you dont act stupid. The paddle hybrid tire sounds like a good idea, but im not sure if metal is the way to go if its a dirt track. The paddle part might grip under hard acceleration and bend? Maybe plastic or something flexible would work.

I think you should use pop bottles for floatation, you really have to use pop bottles in this build somewhere.

highflyer101

carmatic1:

lol... thanks.

hands without shadows:

heh... no prob. I appreciate all the comments.

You may be right on the plastic side paddles. Either way, I won't have them extend out past the edge of the rim. I am shooting to have the MQ floating at about axle level.

Pop bottles, eh? I guess you watched blimp video? That would be funny if I could work them in to this... although I'd have to get a small one or i'd be as big as the MQ. :P

carmatic1

you will have to keep it buoyant enough off the water so that the waterline is at the axle level, yet stop it from tipping over... the waterline therefore has to be around the bottom of the chassis, that foam in the tyres will help keep it afloat , and put some on the sides of the chassis where theres that gap between the chassis and the body... might want to go round the whole tub chassis with it too, nothing worse than water onboard...
also, dont use the foam underneath the chassis , it looks intinuitive but you might scratch it off before you get to the water zone... the pop bottles are rigid , so you can make a raft and improve your stability on water, since your center of gravity will be above the water surface

highflyer101

That all sounds like good advice. Thanks! I don't know if you saw the boat video (a couple posts up above), but I covered the foam in duct tape and that worked pretty well to secure it and protect it. If I were to put foam on the bottom it would be really thin ~1/4", and then I'd tape over it. Although that would decrease the whopping 1.25" ground clearance of the MQ to 1". It may be better to just leave it off as you suggested. I'll have to experiment a little bit to see.