R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 10-16-2008, 09:07 PM   #16
Tech Fanatic
 
trailranger's Avatar
 
Join Date: Feb 2007
Location: Springfield, MO
Posts: 946
Default

Quote:
Originally Posted by Big Daddy Cool View Post
Nothing can be cheaper than using existing equipment, mabuchis and small 2s lipos to start with I believe.
I know of something cheaper to experiement with.... Take a 4-cell NIMH pack and solder off one cell to make a 3-Cell NiMH pack. Most old-school 1:12racers have rx packs but if you don't have one RC4Less.com has them for $10
trailranger is offline   Reply With Quote
Old 10-16-2008, 09:14 PM   #17
Tech Fanatic
 
trailranger's Avatar
 
Join Date: Feb 2007
Location: Springfield, MO
Posts: 946
Default

Quote:
Originally Posted by InspGadgt View Post
I'm not too worried about going slower...I could go for that. But I don't want to get to a point where I have to run a reciever pack.
If a lower voltage change happens for 1:12 or pan oval, you can bet $100 that by the start of following carpet season that high end ESC's will have DC-DC convertors instead of 5V regulators. And will a RX pack be a bad thing till the ESC's catch up? Nitro guys have been running them for many years.
trailranger is offline   Reply With Quote
Old 10-16-2008, 09:29 PM   #18
Tech Elite
 
andrewdoherty's Avatar
 
Join Date: Jan 2005
Location: ★Wylie, TX★
Posts: 3,776
Trader Rating: 47 (100%+)
Default

I have first hand experience with a small 2 cell lipo and a small 380 BL motor mounted in a 12th scale on a medium bite carpet track similar in size to what is run at most big carpet races. I didn't try every motor out there, but I tried to find the least powerful ones I could. It was WAY WAY to fast. It provides a good speed for mod. I would be curious to know what motors would provide a slower than our current stock equivalent when paired with a 2 cell lipo. I even tried a 21.5 540 bl motor and it was also WAY WAY to fast for anyone but experienced seasoned veterans. I understand the prospect of a receiver pack is unpleasant to some. I think a bigger problem would be a 12th scale without a slow enough power package to allow newcomers to control the cars. Good racing is not about speed. The best racing I have ever enjoyed was running mabuchis.
__________________
"Whether you think you can, or think you can't, you're right." -Henry Ford
"[Driving] Genius is 1% inspiration, and 99% perspiration" -T.A. Edison
|◤Hobbywing◢|◤SpeedzoneUSA.com◢|◤Pro-One◢|
|◤ReflexRacing.net◢|◤Protoform◢|◤AVID R/C◢|
andrewdoherty is offline   Reply With Quote
Old 10-16-2008, 10:02 PM   #19
Tech Champion
 
JayBee's Avatar
 
Join Date: Mar 2004
Location: 12TH-MAN COUNTRY
Posts: 6,813
Trader Rating: 31 (100%+)
Default

Quote:
Originally Posted by andrewdoherty View Post
The best racing I have ever enjoyed was running mabuchis.
Preach it brotha We were talking about this last night at the track.
__________________
R C 3 G R A F I X _ F U S I O N . G R A P H I X _ S E A T T L E - R/C - R A C E R S _ E M E R A L D C I T Y R C . C O M

A E - 12R5.2 _ S M - REV8 PRO
JayBee is offline   Reply With Quote
Old 10-16-2008, 10:15 PM   #20
Tech Elite
 
andrewdoherty's Avatar
 
Join Date: Jan 2005
Location: ★Wylie, TX★
Posts: 3,776
Trader Rating: 47 (100%+)
Default

Hmmm . . .maybe a 2 cell Mabuchi would be slow enough in 12th scale . . .
__________________
"Whether you think you can, or think you can't, you're right." -Henry Ford
"[Driving] Genius is 1% inspiration, and 99% perspiration" -T.A. Edison
|◤Hobbywing◢|◤SpeedzoneUSA.com◢|◤Pro-One◢|
|◤ReflexRacing.net◢|◤Protoform◢|◤AVID R/C◢|
andrewdoherty is offline   Reply With Quote
Old 10-16-2008, 10:34 PM   #21
Tech Champion
 
Join Date: Nov 2001
Location: Hawaii, USA
Posts: 7,186
Default

Quote:
Originally Posted by trailranger View Post
If a lower voltage change happens for 1:12 or pan oval, you can bet $100 that by the start of following carpet season that high end ESC's will have DC-DC convertors instead of 5V regulators. And will a RX pack be a bad thing till the ESC's catch up? Nitro guys have been running them for many years.
For me yes it would be. I don't run nitro any longer and disliked worying about a RX pack then. With BL wiring in 1/12th is just getting more and more messy and a RX pack will only add to that. Especially to those who don't have enough channels open on their RX to fit 4 devices plugged into it. As a race director I find it difficult enough to find time to swap batteries and re-peak let alone repeak a RX pack on top of that.

And that's not even considering the change in balance layout a 3 cell NiMh pack would require for the saddle pack guys who hadn't yet converted over to LiPo.
InspGadgt is offline   Reply With Quote
Old 10-16-2008, 11:05 PM   #22
Tech Elite
 
Slapmaster6000's Avatar
 
Join Date: Sep 2004
Location: Edmonds, Wash.
Posts: 3,049
Trader Rating: 16 (100%+)
Default

Let me just start by saying: go for it! Just don't buy the 8kv Mamba, it blows over! I estimated that it should be capable of 57mph indoors... it tried to get there!

I have this set up on a old pos link car that I scratched 10+years ago. It weighs a scant 14.5ou ready to roll. I bought a $9 mini-micro servo that steers just fine. A 1550mah 2c pack from Max Amps for roughly $25. The Mamba esc and motor pack for $125. Yep, doesn't cost that much. All the testing I did was on one set of worn out tires. They don't wear. I beat this thing senseless. Into the wall, drivers stand, pipes, other cars.... I never broke it. I then tested the 5400 which was still faster then a 3.5 with 4 cell. Then I went to a 3600 which slowed down significantly, about a slow 27t. The 4200 should be perfect, but I haven't bought one yet.

Here's the flaws in the grand plan: if it doesn't hook up on asphalt, you cut about 1/2 the 1/12th scale people out of the loop. Manufacturers will not get on board to design a car that will go out to half the people. Game over.

Yes, it will work on carpet. Yes, you will save a lot of money. And yes, it can go faster then you can handle.

Racers are stubborn, they don't want to invest in new products that have not been tried & trued and we have a fear of the unknown.

That still doesn't mean that it's a great idea. If we knew that a year from now, that was the description the future 12th scale..... we'd do it.

I will say this, that little car was more intense then my 8th scale car! It made me grin the entire time.

Brian
Attached Thumbnails
The future of 1/12 scale-p1160005.jpg   The future of 1/12 scale-p1160004.jpg   The future of 1/12 scale-p1160001.jpg  
Slapmaster6000 is offline   Reply With Quote
Old 10-16-2008, 11:31 PM   #23
Tech Master
 
Big Daddy Cool's Avatar
 
Join Date: Aug 2001
Location: Makati, Philippines
Posts: 1,725
Trader Rating: 15 (100%+)
Send a message via ICQ to Big Daddy Cool
Default

Quote:
Originally Posted by JayBee View Post
Preach it brotha We were talking about this last night at the track.
Quote:
Originally Posted by andrewdoherty View Post
Hmmm . . .maybe a 2 cell Mabuchi would be slow enough in 12th scale . . .

2S Mabuchis in F1 average about 16 secs per lap vs 15secs per lap on 23Turn brushed / 13.5 BL stock TC in my club's track (smooth indoor asphalt) . I would estimate 2S Mabuchi powered 1/12 to match or even go slightly faster than the 13.5BL powered TCs.


Brian: Do the 380BLs mount straight onto the motor mount or did you need a different mount? Thanks.
Big Daddy Cool is offline   Reply With Quote
Old 10-16-2008, 11:43 PM   #24
Tech Fanatic
 
Join Date: Jun 2005
Posts: 900
Default

Balanced view, Slapmaster, thanks.

A piece of advice from a dedicated 12th racer (30 years) to those who want to change it - change your rhetoric. If you want people like me on board (dedicated 12th racer, fast-follower in most things new, early adopter in others, disposable income) then you have to stop telling me that there is something wrong with me for not immediately jumping on your bandwagon.

Words like stubborn, lost in the past, hating change, etc. just make me get on here and flame you. My Company works in a rapidly changing market, my role involves creating change, and the World around me is changing daily. My hobby, on the other hand, is relatively stable. I don't think I am unusual.

The big attraction of 12th is that it doesn't change. I don't have to be at all the big meetings making sure I know what the latest thing is, I don't have to worry about finding out what the latest thing does to my set-ups, etc. etc. My hobby is for fun, not for more hard work. If you want to make changes, for me, they are going to have to a lot easier than ripping everything out and replacing it all in one go.

And, it isn't that we don't promote and adopt change. Look here at what cars used to be like and tell me 12th hasn't changed. But look carefully and you find that each change came along slowly, and it didn't alienate half the drivers in one stroke. That's how 12th works, and has survived so long.

Big chunks of change don't suit everyone, and telling them they have some character flaw if they don't adopt some (badly thought through, in this case, as Slapmaster points out) radical change isn't your best marketing ploy. Sell to me by all means, but name-calling will make me hang up on you - and hundreds of others will do the same.
SlowerOne is offline   Reply With Quote
Old 10-17-2008, 01:10 AM   #25
Tech Champion
 
Scottrik's Avatar
 
Join Date: Sep 2004
Location: Billings, MT
Posts: 6,212
Trader Rating: 245 (100%+)
Default

I've done a LOT of thinking and research on this and plan to put together a similar test hack. I will test 2s LiPo but will install a, comparatively, VERY slow motor. I found a company that makes a full line of 380 size brushless motors down to 34T. Unfortunately no one in the states carries them. I believe I finally located a source overseas that can get me a couple of these to play around with.

It's been a couple months since I was seriously looking at this...it got put on the back burner because there are a couple things about the idea(s) that I wanted to run past Bob Stormer who usually has some neat ideas about what's what. As luck has it he plans to be down to race with us this weekend so I dug out my info and look forward to sorting this out so I can get the motors ordered up.

The motor I'm looking at as a 4-cell/17.5 equivalent is a 380 size motor with a 48mm long can. This will JUST fit into a current motor pod with the requisite adapter to pick up the smaller mounting screw circle. Oh yeah, it also has a .125 shaft diameter which makes it work with our pinions rather than the ones for the micro cars.

According to Novak's published specs their SS17.5 Pro is a 2.2kv motor (THIS is why the 5.4-8.0kv motors commonly available for minis are too powerful). 2.2kv gives 10,560 rpm at 4.8 volts (the nominal 1/12 voltage). Divide that 10,560 rpm by 7.4v (nominal 2s LiPo voltage) and you get 1,427 rpm/volt (1.427kv if you prefer) as the desireable RPM that would give the same top speed potential. Sure enough, the 27T bl motor I'm looking at is listed as 1462 rpm/volt (1.462kv) and the 28T is 1410. Neatly bracketed.

Further, the Novak SS17.5 Pro is described as a 130 watt motor. Both the 27T and 28T motors on my short list are rated at 15 amps. 15 amps times 7.4 volts gives 111 watts which is not quite 15% less. This, it turns out, should be just ducky because my projected weight savings is approximately 25%. I think these would accelerate pretty much the same and have a similar top speed to the SS17.5 Pro.

Weights? The Novak motor is spec'd at 6.61oz (approx 187 grams). The motor I'm looking at weighs 136 grams. A bare Ener-G 4600 cell from SMC weighs 68.8 grams, four cells would be about 275 grams PLUS five battery bars and some solder. Figure 280g minimum? A MaxAmps 2000mah LiPo weighs in at 120g (add more once a hard case is added). That's a savings of about 211 grams, or approximately a 25% weight savings over my DB12R at race weight. I could add a bit of weight as necessary and STILL have a 15-20% lighter car.

Just some stuff in my head until I pull the trigger on the motors. I'll probably end up having to buy a few. We're not going to be going to 13.5 in SuperStock until our 2009-2010 season so if I want to compare with what we're running SuperStock this coming season I need a 10.5 equivalent which puts us in the 14-15T range for this mystery motor and yields approx. 207 watts compared with the SS10.5 Pro at 235watts.

The truly challenging part in this is that none of the current larger capacity LiPos will fit the space allowed--they're all just a hint too long for either my BMI or CRC chassied cars. Then again my Slider runs about forever on a 1550mah LiPo with an 8.0KV motor so I'm pretty sure the car I'm proposing would run just fine for 8 minutes (or more) on 2000 mah.

My biggest concern is the low speed/accelerating from rest performance from such a high wind motor in a sensorless application. I will probably use one of my Tekin Mini-Rage esc's for these experiments. I would DEFINITELY prefer something like the Mongoose but, again, the lowest spec motor is still WAY too much for what we're talking about here.

Anybody see obvious flaws in my reasoning? I'd sure like to find any that might be lurking here before I commit a couple-three hundred bucks to the idea.

Scottrik
__________________
Congressmen should wear uniforms like NASCAR drivers so we can identify their corporate sponsors.

THE REVOLUTION WILL NOT BE TELEVISED -Gil Scott-Heron (1949-2011)
Scottrik is offline   Reply With Quote
Old 10-17-2008, 01:14 AM   #26
Tech Elite
 
Trips's Avatar
 
Join Date: Aug 2001
Location: 360 Speedway
Posts: 2,251
Trader Rating: 16 (100%+)
Default

I am probably not the guy to ask on this topic, because I don't really want to see change in 1/12 scale, but if I were to pick, I'd choose the 2 cell/small motor concept over the single-cell and receiver pack option. I've tried receiver packs at various times over the years (and I've been actively racing 1/12 since 1979) and I';ve never had much of anything good to say about them.

I've seen Roland's car run, and I've driven it myself, and the concept works.

Just my own opinion here...
__________________
MARSHAL!!
Trips is offline   Reply With Quote
Old 10-17-2008, 01:31 AM   #27
Tech Master
 
linger's Avatar
 
Join Date: Aug 2001
Location: Retired
Posts: 1,132
Trader Rating: 1 (100%+)
Default

Roland,
Thanks for bringing up a great topic. You have obviously given this much thought.

I once tried 1 cell lipo and it was too slow (for me) regardless of motor. Driving full wood all the time was boring.

I once tried 2 cell with 540 sized motors and it was too fast....silly fast. Unraceable.

Here's another thing to try. A123 makes a 18650 sized battery rated at 1100mAh that is only about 3 volts. It's super safe, has great current capability, and great cycle life. You can build a 2S2P pack for a total of 2200mAh at 6V or maybe try to fit in a 2s3p pack for 3300mAh at 6V.
It would be the same voltage as 4 cell NIMH. No changes to the motor or rear pod. The graphite chassis may eventually need mods, but that's minor since cutting graphite is not exactly a mass production operation.
__________________
I used to be a spitter, now I'm a swallower. I graduated.
linger is offline   Reply With Quote
Old 10-17-2008, 02:21 AM   #28
Tech Champion
 
Join Date: Nov 2001
Location: Hawaii, USA
Posts: 7,186
Default

I really like the 2 cell and 380 size motor idea...when you think past the conversion to what it eventually would be come, a purpose built 2 cell 380 motor would have a pod at least 30% smaller if not more and definately lower, more chassis room to move electronics and batteries around to find their ultimate balance point. All on a chassis with a much lower profile which opens up more body design possibilities, hopefully ones that look much more scale to the car they are copying. Don't get me wrong I think the bodies we have now look good...just don't have the scale looks I'd love to see and run. When I first got into 1/10th pan that is one of the things I loved most about the cars were some of the beautiful bodies out there...the Bud Light Jag, the Andy's 962 and more that I just can't think of off-hand. Tamiya still manages to make some incredibly scale 1/10th pan car bodies for their chassis...I'd love to see that kind of detail come to 1/12th as well.
InspGadgt is offline   Reply With Quote
Old 10-17-2008, 02:44 AM   #29
Tech Master
 
Big Daddy Cool's Avatar
 
Join Date: Aug 2001
Location: Makati, Philippines
Posts: 1,725
Trader Rating: 15 (100%+)
Send a message via ICQ to Big Daddy Cool
Default

Quote:
Originally Posted by InspGadgt View Post
..... Don't get me wrong I think the bodies we have now look good...just don't have the scale looks I'd love to see and run. When I first got into 1/10th pan that is one of the things I loved most about the cars were some of the beautiful bodies out there...the Bud Light Jag, the Andy's 962 and more that I just can't think of off-hand. Tamiya still manages to make some incredibly scale 1/10th pan car bodies for their chassis...I'd love to see that kind of detail come to 1/12th as well.
I agree. I wish 1/12 had bodies that look like the ones below:
Attached Thumbnails
The future of 1/12 scale-picture-5b.jpg   The future of 1/12 scale-picture-7b.jpg  
Big Daddy Cool is offline   Reply With Quote
Old 10-17-2008, 05:05 AM   #30
Tech Adept
 
Join Date: Jan 2007
Location: Switzerland
Posts: 131
Default

2S-Lipo with Brushless 380 sounds good. For Racers who don't like speed, there are also brushed mabuchi 380 motors available
Hm, I saw a Lipo 380-Brushless 12th scaler on youtube, but don't remember its name. Does anyone know this vid?

If the cars need more weight. replace the graphite parts through glassfiber parts and the aluminium screws through steel screws. That will also keep the costs down.
Der Dicke is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
1/12 forum ovalnator Electric On-Road 46189 12-15-2017 08:13 AM
1/10th pan car Taz_S Oval, Larger Scales and More 16138 09-25-2014 10:03 AM
The Nitro Pit Dbackmasta Arizona-New Mexico Racing 18732 09-13-2012 09:27 AM
new 19t motor from peak sukh Electric On-Road 77 07-13-2007 03:12 PM
The future of RC? - New Radio Technology stuff Electric On-Road 275 11-09-2005 01:49 PM
The Future Of The Nct....... Mike Dana Northwest Racers 122 09-02-2004 04:23 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 09:24 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net