New hi-speed project - Page 2 - RC-Monster Forums

BrianG · 12.26.2007, 05:59 PM

Not sure about what I want to do about the clutch yet. I'll know more when it sits in front of me. Due to the wallet-draining holidays, I'm planning to make some purchases around tax-time (maybe a tad sooner), unless I can off-load the Hellfire roller. The under $100 price tag of the Yusa model is attractive, but I always seem to break the things that can only be found by ordering specific parts.

12.26.2007, 06:11 PM

This is going to be good! I'd say 1521 is a good choice, and I wouldn't spin it slower than 50k RPM! Aim for 60k at nominal voltage as I think at full tap your pack will probably drop below 3.7V/cell anyway.

A car like this is probably going to need about 4 kW of power.

ssspconcepts · 12.26.2007, 06:34 PM

Brian,

This should really be a cool project! I can't wait to see what you come up with as an end product. I have been eyeballing the Ultra GTP for a long time and have been considering a similar build....except I wouldn't be going for the extreme high speeds that you are. What motor mount would you use-the CR buggy?

BrianG · 12.26.2007, 07:45 PM

Not sure about the mount. Probably have Mike do something special to be strong and as light-weight as possible. For batteries, some type of cell with a REALLY good C rating, like FP or something like that. Don't need high capacity per se, mostly very high short-duration power that is as light as possible. If I can find some decent prices on 1/8" thick CF sheets, I might re-fab some of the existing Al pieces for weight. I want strong, yet durable. But it has to be pretty too.

I'm open to any suggestions if anyone can think of any...

jhautz · 09:21 PM

Brian,

If you are worried about the motor mount it might be easier than you think. The DM1 I did uses the same center diff uprights as the Jammin Buggy so the RCM Jammin Buggy motor mount was a direct drop in fit. My suspicion is that the GTP is probably the same upright because it uses the same 2 speed as the DM1 so it only stands to logic they would use the same upright.

Its possible I'm wrong, I haven't checked any part numbers or anything for the gtp, but I think you have a great shot at it being a simple solution. Do some part number research on the ofna website.

And if you are looking for a simple 2 speed solution check out Mikes 2 speed pinion adapter. He now has a whole range of pinion gears available for it. I got a setup from him and it is solid and really simple setup. It should work for your application perfectly. I was also thinking about playing around and seeing if Mike could make me some "special" pinion gears for the 2 speed adapter of his. I was thinking I wanted to get a 32/37 pinion setup to use with the Ofna 44/49 2 speed spur gears on the 2 speed tranny. I was going to target 100+ as a goof around setup on the DM1 just to see if I could do it.

I'm sure he could make (or get made) any tooth count we need. It might cost a few $ to get it, but If we both want a set we could split the setup costs associated with any special gears.

ssspconcepts · 12.26.2007, 09:23 PM

Quote:

Originally Posted by jhautz

Brian,

If you are worried about the motor mount it might be easier than you tink. The DM1 I did uses the same center diff uprights as the Jammin Buggy so the RCM Jammin Buggy motor mount was a direct drop in fit. My suspision is that the GTP is probably the same upright because it uses the same 2 speed as the DM1 so it only stands to logic they would use the same upright.

Its possible Im wrong, I havent checked any part numbers or anything for the gtp, but I think you have a great shot at it being a simple solution. Do some part number research on the ofna website.

And if you are looking for a simple 2 speed solution check out Mikes 2 speed pinion adapter. He now has a whole range of pnion gears available for it. I got a setup from him and it is solid and really simple setup. It should work for your application perfectly. I was also thinking about playing around and seeing if Mike could make me som "special" pinion gears for the 2 speed adapter of his. I was thinking I wanted to get a 32/37 pinion setup to use with the Ofna 44/49 2 speed spur gears on the 2 speed tranny. I was going to target 100+ as a goof around setup on the DM1 just to see if I could do it.

I'm sure he could make (or get made) any tooth count we need. It might cost a few $ to get it, but If we both want a set we could split the setup costs assiciated with any special gears.

I think you are right...if I were to build an Ultra GTP, I'd try the Jammin CR mount and ditch the 2-speed for a center diff....I guess for the high speed stuff this is not optimal, but it is simpler and would be fun to build/drive.

nl12 · 12.26.2007, 09:34 PM

I would not spin a 1521 anywhere near 50k in a car or truck, I believe it would pull too many amps. I would spin a 1512 that fast on a good controler, consider the fan option on the neu to keep the temps well in control if you are going to spin it 50-60K

lincpimp · 12.26.2007, 09:37 PM

If you guys decide to have any special size gears made for the 2 speed adapter let me know. I have quite a few 2 speed vehicles ready to convert.

Also, any ideas how I would get in touch with mike? I would like to buy a 2 speed adapter from him, but need it to have a 6mm bore to fit my kb45 motor. I would drill it out myself, but do not want it to wobble. I am sure that mike's equipment is better than mine!

jhautz · 12.26.2007, 09:41 PM

Quote:

Originally Posted by lincpimp

If you guys decide to have any special size gears made for the 2 speed adapter let me know. I have quite a few 2 speed vehicles ready to convert.

Also, any ideas how I would get in touch with mike? I would like to buy a 2 speed adapter from him, but need it to have a 6mm bore to fit my kb45 motor. I would drill it out myself, but do not want it to wobble. I am sure that mike's equipment is better than mine!

The gears I'm talking about wouldnt be for everyday use. WAY to tall of a gearing setup. He has the adapter and gears ready to go for most "normal" 2 speed conversion applications. I think you might have a problem with the 6mm hole though... There isnt a whole lot of room inside there to make the hole bigger. It migh be possible though. You can reach mike at rcmonstermike@gmail.com

lincpimp · 12.26.2007, 10:09 PM

Quote:

Originally Posted by jhautz

The gears I'm talking about wouldnt be for everyday use. WAY to tall of a gearing setup. He has the adapter and gears ready to go for most "normal" 2 speed conversion applications. I think you might have a problem with the 6mm hole though... There isnt a whole lot of room inside there to make the hole bigger. It migh be possible though. You can reach mike at rcmonstermike@gmail.com

I have tried that email address twice now, I will give him a few more days!

There should be enough material to enlarger the hole to 6mm. The stock losi clutch bell uses a 5x10mm bearing, and still allows for the thread on gears.

And I would not use them for everyday use. I am building a on road car, for straightline speed, if it all goes well. I will test it with a more sane setup first and then increase the speed to test the aerodymanic requirements. I have already done this with a 10th scale car, so I have some ideas what will work!

pcnutz · 12.26.2007, 10:15 PM

I hate to bust your bubble, less you want to take a push broom out and sweep 250 yards of road, a high speed sedan is not going to be too much fun, I tried it with tc3 and 1930/5

lincpimp · 12.26.2007, 10:26 PM

Quote:

Originally Posted by pcnutz

I hate to bust your bubble, less you want to take a push broom out and sweep 250 yards of road, a high speed sedan is not going to be too much fun, I tried it with tc3 and 1930/5

Actully I found a decent blacktop area and unprepared it allowed my tt01 based car to do 74 mph. It would have gone faster, but I need a longer space. It is maybe 300 feet long. We actually added about 20 feet to the radar position and gained about 8 mph, so I would love to have about 250 yards. I have a feeling that the car as is would top 80mph, stock out of the box with bl power and foam tires! Plus 10 guys with brooms would make short work of sweeping!

pcnutz · 10:31 PM

well don't take me litteral on 250 yard, but you would need 10 guys and 10 push brooms to make short of an area needed and phat chance scaring up enough people to do that, I have a hard time just finding a turn marshal or camera man

glassdoctor · 12.26.2007, 10:40 PM

BG... that Yusa car is cheap enough you could buy a second car for parts... or even a third lol

lincpimp · 12.26.2007, 11:09 PM

Quote:

Originally Posted by pcnutz

well don't take me litteral on 250 yard, but you would need 10 guys and 10 push brooms to make short of an area needed and phat chance scaring up enough people to do that, I have a hard time just finding a turn marshal or camera man

If a rc car could close in on 100mph, I would easily be able to have 10 guys there to sweep and watch. There is generally at least 6 of when we go out and play.