Tamiya Dynahead build - help chosing components

[macordani]

Hi I grew up with old school Tamiya and Kyosho back when I was a kid and my first car was the Hornet. Now I have been getting my two young kids involved. So I know many of you here may laugh at the Dynahead, but honestly it looks like my kids and I will have a blast with it. They don't need something to go 30mph and end up in a broken scrap heap. We live right next door to state forest so have plenty of terrain to mess with.

So anyways this build is more advanced than my prior knowledge, especially since I want to build it with 4WS. My first question is I see people build them with regular radios and a Y servo splitter, while others build with a 4 channel receiver capable of 4WS mixing. So I wanted to know if mixing is worth it, and if so I found a radio, Futaba 3PV with telemetry, that is capable of 4WS mixing. I have always liked Futaba, unless you guys think another radio is better.

Then from there was thinking of using two Futaba S3010 high torque BB servos for steering. Would these be fine for the build?

Then lastly, for now , the esc choices, there are so many! Should I even worry about a future upgrade to a brushless motor, or would a future upgraded brushed motor do? From what I've read a good brushed motor is good enough for this rig. Taking the above into account what would be a good esc choice?

Thanks in advance for the help!

 

[JatoTheRipper]

Welcome to the site!

Before I begin, I will state that I have absolutely no experience with the Dynahead or any of the Tamiya 6x6's, but I'm going to give you help based on my RC experience.

You have to decide how you want your 4WS to operate. If you just want the rear to steer opposite of the front at all times a splitter is fine. But if you want to steer the front and rear independently or if you want to do crab walks you'll need another channel for the rear steering servo. Futaba is a great brand though and there's none better. Cheaper than Futaba? Certainly. Better? Nope.

That Futaba servo doesn't really have high torque at all. I'd certainly want more. I'd suggest at looking for 200oz-in minimum.

Checkout the HobbyWing WP 1080 ESC. It's tough to find right now, but there some on eBay. That's a great crawling ESC that should do fine with the Dynahead.

 

[macordani]

Welcome to the site!

Before I begin, I will state that I have absolutely no experience with the Dynahead or any of the Tamiya 6x6's, but I'm going to give you help based on my RC experience.

You have to decide how you want your 4WS to operate. If you just want the rear to steer opposite of the front at all times a splitter is fine. But if you want to steer the front and rear independently or if you want to do crab walks you'll need another channel for the rear steering servo. Futaba is a great brand though and there's none better. Cheaper than Futaba? Certainly. Better? Nope.

That Futaba servo doesn't really have high torque at all. I'd certainly want more. I'd suggest at looking for 200oz-in minimum.

Checkout the HobbyWing WP 1080 ESC. It's tough to find right now, but there some on eBay. That's a great crawling ESC that should do fine with the Dynahead.

Thanks a lot for the info. I figured it wasn't a true crawler, but thought this site would be good to get info, especially with the 4ws.

Hmmmmm yea I'm not even sure it would be useful having independent 4WS or doing crab walking with this machine. It is kind of slow, so I see no downside to it being in 4WS at all times. Thoughts?

Funny I didn't know the torques varied that much within the "high torque" grouping. Are there good high torque servos that won't break the bank? I probably don't want a digital one as I read they drain the batteries faster, and this will already drink it up I'm thinking.

Thanks on the ESC I'll look into it. You guys have much more knowledge so appreciate it. I just don't want to build it, then realize I should have done something better and wasted the money.

 

[Gula]

Im sure OSRC the master of tamiya and owner of one of these will chime in soon. Wp1080 esc, 35t motor, 2x 200oz/in servos and you should be good.

 

[themountain]

Im sure OSRC the master of tamiya and owner of one of these will chime in soon. Wp1080 esc, 35t motor, 2x 200oz/in servos and you should be good.

Copy that...OSRC is the Tamiya go to guy

 

[macordani]

Im sure OSRC the master of tamiya and owner of one of these will chime in soon. Wp1080 esc, 35t motor, 2x 200oz/in servos and you should be good.

That hobbywing crawler wp1080 esc looks really nice. Says it comes with a xt60 battery connector, so best thing to do for me is get an adapter for it, as NiMh batteries I use have the standard Tamiya type plug? This sound like what I should do, cheap adapter for esc to use standard battery?

Thanks looking forward to others chiming in including OSRC. Also if anyone can recommend good servos that won’t break the bank I would appreciate it. Only brand I’ve ever used is futaba so I really don’t know much about other brands that are good. Thanks again.

 

[macordani]

Oh also realized the esc looks like it doesn’t come with motor connectors on on it. Would I solder on bullet connectors? If I put on bullet connectors it looks like the ones that come on most motors are different than the ones I would solder on, so guess would cut those off and solder on matching bullet connectors. Unless you guys use different connectors for motors?

 

[Gula]

It would be best.if you swap your battery connectors to deans, and eliminate the bullet plugs on the motor, and just direct solder the esc wires to tbe motor.

 

[macordani]

I actually see some 7.2NiMh batteries with xt60 connectors now so that shouldn’t be a problem. Can just use an adapter on my charger and should be all set.

If not soldering the wires directly to the motor, does anyone ever use better connectors for that, like Deans?

As far as servos go I see Hitec D645MW look pretty good, not quite 200 on the torque scale but pretty close, and rated really good.

I’ll wait on OSRC and others to opine on whether I should get the better Futaba radio that has 4WS mixing, or just use a Y splitter and have it in 4WS all the time. Thanks again all.

 

[OSRC]

Master of Tamiya? Hardly, you guys are funny. I'm just a dork in his basement playing with tiny cars. I don't have a Dynahead, though I do have a Konghead, its little brother.

I run my Konghead with 2WS and it's .. ok. Turning radius is way large though, and when I locked the diffs - forget it. It just plowed. For the Dyna, I'd think you'd want 4WS - at least I know I would.

Not sure what I can add that hasn't been mentioned. A pair of 200oz ish servos should be fine. I'm using a single old Airtronics POS 130oz or so and it swings the wheels just fine. The portals add some frission to the steering, but 200 should swing them no problem since it's an open diff. Some of the "25kg" servos on Ebay should do the job, they are pretty decent bang for the buck and they use 25t splines so they'll work well with the kit (using the Futaba steering horns)

As far as the radio, typical RC rule 101 applies. Buy the best you can afford. Even if its overkill for this model, it may come in handy for the next. Futaba 3PV would be perfect. OR a Spektrum of some variety... 3-4 channel radios aren't terribly expensive anymore and 3rd channel mixing is pretty common now.

 

[macordani]

Master of Tamiya? Hardly, you guys are funny. I'm just a dork in his basement playing with tiny cars. I don't have a Dynahead, though I do have a Konghead, its little brother.

I run my Konghead with 2WS and it's .. ok. Turning radius is way large though, and when I locked the diffs - forget it. It just plowed. For the Dyna, I'd think you'd want 4WS - at least I know I would.

Not sure what I can add that hasn't been mentioned. A pair of 200oz ish servos should be fine. I'm using a single old Airtronics POS 130oz or so and it swings the wheels just fine. The portals add some frission to the steering, but 200 should swing them no problem since it's an open diff. Some of the "25kg" servos on Ebay should do the job, they are pretty decent bang for the buck and they use 25t splines so they'll work well with the kit (using the Futaba steering horns)

As far as the radio, typical RC rule 101 applies. Buy the best you can afford. Even if its overkill for this model, it may come in handy for the next. Futaba 3PV would be perfect. OR a Spektrum of some variety... 3-4 channel radios aren't terribly expensive anymore and 3rd channel mixing is pretty common now.

Thanks OSRC I appreciate the help! With that I think I'll be mostly good on the build. I'll look to do some hop ups early on too like the Tamiya servo mounts, including the bracket that lets you mount the servo lower/better, the steering arm, and likely the front skid plate.

A few stupid questions on the motor. Folks said a 35T would be good. Question is does more turns make it slower? Slower than the stock motor? As it isn't fast to begin with so not sure I want it slower, I don't need it faster, but don't want to make it a slug. Also if I were to add motor connectors are Deans a good choice over bullets? I like the ability to be able to disconnect the motor if I want to vs direct solder.

 

[OSRC]

The stock motor is roughly a 27t. The higher the turns, the lower the overall RPM/volt.

There's quite a gearing drop due to the portals, and I assume the stock kit uses an 18t pinion like the Konghead. I'd personally wait and drive it first before making any motor decisions. The stock motor might be fine for your needs, and it's free. Get a baseline first before dropping any more cash.

I'd recommend gold 3mm bullet connectors for the motor leads. Low loss, easily swapped. Deans are directional, and in some cases you may need to run the motor in reverse rotation depending on how the truck its installed in is geared. Bullets can easy be swapped around whereas deans cannot. Plus you can always solder up a few leads and more easily swap motors in and out of various vehicles.

 

[macordani]

The stock motor is roughly a 27t. The lower the turns, the lower the overall RPM/volt.

There's quite a gearing drop due to the portals, and I assume the stock kit uses an 18t pinion like the Konghead. I'd personally wait and drive it first before making any motor decisions. The stock motor might be fine for your needs, and it's free. Get a baseline first before dropping any more cash.

I'd recommend gold 3mm bullet connectors for the motor leads. Low loss, easily swapped. Deans are directional, and in some cases you may need to run the motor in reverse rotation depending on how the truck its installed in is geared. Bullets can easy be swapped around whereas deans cannot. Plus you can always solder up a few leads and more easily swap motors in and out of various vehicles.

Great info OSCR, both very helpful. Thanks again.

 

[RobertSX4]

Apologies if I am replying too late to be of any help

I just finished my Dynahead G6-01TR chassis with 4WS, I still have to do the body.
I chose a Hobbywing 1080 ESC, direct soldered to the motor

Motor is the Holmes hobbies trailmaster sport 550 27T, on 11.1v I get 5-7 mph I think (my estimation isn't that great) which is what I want for trail/crawling

I chose the DS3225MG 25kg servos, they're cheap, strong, and metal geared, but when I tested them out one was markedly slower (I just threw that one on the rear steer and will see if it burns out quickly) so I think QC may be where they get you.

If you need to change connectors the XT60 is the best IMO, very good connection, just ensure you purchase name brand ones.

I use a hobby porter radio system, it offers 4 different steering modes (normal, crab, rear steer only, and the normal 4ws mode).

You could also get a splitter module thing that will allow you to chose multiple steering modes with a 2 channel radio system but I can't remember what exactly they are called off the top of my head.

 

[OSRC]

So macordani, how'd you make out? Got anything built yet?

I'm intrigued by the portals, I skipped the Dyna since it's so close to the Konghead, and I don't own stock in a bearing company, but I did order a Beetle trail to mess with just because it had the portals. (And Tamiya was blowing them out for $169 shipped) I'm sure the portals will make their way onto another vehicle at some point.