Ofna DM-One Brushless Conversion (DM-1)
 

New project time. This one will probably take a little while to get through. I am planning to take my time and get it right. I have basically till spring. Somehow I'm afraid I will dig into it and get completely sucked in and be done with it WAY earlier than I intend to.

I'm going to do my best to photo docment this one from begining to end. Here are the first pictures. Opening a box with a new RC is one of the most fun moments.:mdr:

I have been doing a ton of research on this DM-1 and it shares MANY components with the Jammin Buggy and Truggy. This means 2 things to me, A) most replacement parts shoud be easy to get even though this is not a super popular model. B) The motor mount is going to be very easy as the RCM Jammin Buggy mount should be a direct bolt in since the DM-1 uses the same center diff mounts.

Dimensions of the chassis are the same width as a standard 1/8 buggy but with a narrow 3 inch extended chassis and no kick up

I am planning to keep the 2 speed and the mechanical brake for this one so it will hopefully lighten the load on the ESC to the point where I can run the Quark without needing any crazy mods and still not overheating it. The motor is going to be a Lehner 1950/7 and I'm planning 5s.

First step will be to decide how I'm gonna lay this out. This chassis is so long I think I have some options. I just need to figure out what will work best and where I want the brake servo to go.

Here are the pics: More to follow when I make some progress.
The box got here Friday::yipi:
http://i66.photobucket.com/albums/h2...n/c4707632.jpg

I could hardly wait to tear into it:
http://i66.photobucket.com/albums/h2...n/875f9e95.jpg

The body on this thing is going to take a gallon of paint to cover.... Its huge! (I got the Carrera body)
http://i66.photobucket.com/albums/h2...n/0826bf9f.jpg

Ahhh... There it is. :smile:
http://i66.photobucket.com/albums/h2...n/15290260.jpg

All of the other stuff that still needs to be assembled. But honestly most of it is notro bits that just wont get used.:neutral:
http://i66.photobucket.com/albums/h2...n/3eeb9934.jpg

Some of the other parts that I have collected for this project.
http://i66.photobucket.com/albums/h2...n/1a143009.jpg

Very nice. You have to make some videos of this beauty running.

That thing is going to be sick... Good thinking to stick with mechanical brakes. If you ever wanted this thing HV to make it go fast, those mech. brakes would come in handy.

It might be a while for vids.

Heres a pic of what I am thinking the layout will look like. The brake servo still needs to be thought through. It might get moved in between the battery and the front center drive shaft.

http://i66.photobucket.com/albums/h2...n/947304ab.jpg

Im def watching this build close!

Those are such awesome cars!

Very sweet, are you the first one to try and convert one?

Bye:mdr:

Don't know. I haven't seen one yet though. Its not really much different than converting a truggy except the chassis is a little narrower and its a 2 speed instead of a center diff.

Word. That thing WILL be sick, a 1950 JHautz? Really?! :surprised:

where did you get a 2 speed pinion?

Nice! The DM-1 is a really sweet car, and looks much better than the Kyosho Inferno GT's due to it having a much more realistic wheelbase. This is gonna absolutely fly. Good luck with the conversion, I'll be watching this thread closely. :)

more horizontal shocks?! so the revo and F201 aren't the only cars with these? interesting...

now, you said that this car shares many components with jammin. are you going to convert this sedan into a buggy, or what's going on here?

other than that... looks really fun!! GL!

Cool Jeff!

This should be a nice conversion! i didn't knew these cars excisted.. I was struggling with that stupid belt on my serpent and weird motorplacement on the serpent. This should be a dream to convert! cool project Jeff.!

btw; Ditch that 2speed..

Trust me, the wheels will be screaming for grip all the way.. the serpent with the softest shore tires was having serious wheelspin when going from 70% wot to 100% wot..

that was with an XL2400 on 4S...

nl12 - I made the 2 speed pinion. I cut off the bell on a 2 speed clutch bell and used the screew on 20T and 16T gears. This one http://www.hobbypeople.net/gallery/149797.asp Then I made an aluminum insert with the set screw and 5mm shaft hole that press fit into the place where the bearings go in in the clutch bell and JB welded it into place. I was actually using it in my XLB 2 speed setup so I had it already. I will make another one when I get a chance. I'm using this one for fitting everything up and to get it up and running until I can get around to making another one.

Mallanaga - No I'm not converting it to a buggy, just converting it to electric from nitro. I'm planning to use it for parking lot oval racing.


ZPB - What? A 1950 isnt big enough for you?

Dagger - I agree. I looked at the Kyosho GT and the Ofna GTP but they both looked like rather cheaply built buggies with shorter shocks and shock towers. I like the lay down shock configuration like some of the 1/10 touring cars. It looks like it was more specifically designed for on road than just a modified buggy setup.

I may wind up ditching it after I get it built and tested. Just a matter of droping in a standard center diff and changing the pinion. I'll see once I get it running and decide then. For now I am going to plan on using the 2 speed.

Another benfit of going with a center diff may be better cornering, but once again I can decide this once its up and running.

EDIT: And btw... I'll be runnign rubber tires on this, not foams. It takes standard 1/8 buggy wheels and buggy on road tires.

I don't know what has more grip.. Fresh soft foams or rubber. i would say rubber has got more grip (or should be able to have more grip) no idea if this is a fact.

Ive tried both on a buggy set up for pavement oval and it depends on the surface.... But in general rubber has much more bite.

Yeah, it should be, since there is more material in touch with the road.

I'm going to keep both eyeballs on this thread. This is the conversion I want to do for next summer.
For some reason I feel that belt drives are so eighties. This driveshaft driven roadie will be awesome.

You could get some rubber slicks (which I think have more traction than foams until they balloon) and keep the two-speed. Even then you could make it a drift car at will.

AWESOME!

FOr tires, you can check out the GRP 1/8th scale grove tires. SUPER low profile and sweet multispoke rims. Plus they're premounted.

I use a solid center spur gear in my Ofna buggy and it made a difference in how it puts the power down. I don't remember the part number, but here is the picture of it:

Little update:

I had a couple hours to work on this the last 2 nights. Here are a couple pics of the progress.

Last Nights progress:

Finished asembling the rest of the stock chassis minus the nitro parts. I gotta say I like it. It seems to be a quality setup. Fit and finish is really good. Installed the steering servo (airtronics 94359). Motor mount and motor is installed. The RCM Jammin buggy motor mount is a perfect drop in fit. Also on these pictures you can see the 2 speed pinion that I made in a little more detail. I need to add a couple shims behind the small gear to get the gear to gear spacing right. You can see in the pics that the pinions are closer together than the spurs right now. I'm just waiting on some shims I ordered to get here.
http://i66.photobucket.com/albums/h2...n/f53217fa.jpg

http://i66.photobucket.com/albums/h2...n/33a2a092.jpg

http://i66.photobucket.com/albums/h2...n/3f504754.jpg


Tonights progress:

Got the top plate for the steering servo cut and installed. Replaced the plastic center diff top plate with a carbon fiber one I had in a bunch of old parts from a Hyper 7. It just luckely fit perfectly so I figured what the hell. Made the battery box from my last 2 pieces of carbon fiber angle from graphiteelegance. They were salvaged from another battery tray that I dodnt need any more so they are kind used and scuffed up before I even started, but its all I had and this stuff is expensive since graphiteelegance closed for "vacation" so I'm using what I got for now. They are a 2x2 and a 1x2 angle stock. The 2x2 is mounts next to the spur gears and I left it 2 inches tall for 2 reasons. 1) it will protect the lipos from the spur, and 2) I am planning to mount the brake servo to the back side of it between the battery tray and the front dog bone. I overlapped thee 2 pieces on the bottom and then drilled 3 holes thru them and thru the aluminum chassis. I counter sunk the CF so the screw heads were flush and lipo could sit flat. Then I tapped the holes in the chassis so I could just screw it down directly to the chassis without anything protruding out the bottom. The chassis is 7075 so it should hold the threads. The whole assembly feels really solid and I'm pretty happy with it considering I started with just a buch of used scraps. Then to hold the battery in I put a layer of Velcro on the bottom of the tray to hold the lipo and to provide a little cusion for it too. I also mounted a strap over the top by using a couple convieniently located holes in the chassis that were meant for someting to do with the nitro kit.

Here are a couple pics of how it sits right now. You can really see the scufffs in the CF in the battery tray close up. :grrrrrr:

http://i66.photobucket.com/albums/h2...n/e66233ec.jpg
http://i66.photobucket.com/albums/h2...n/0ead7684.jpg
http://i66.photobucket.com/albums/h2...n/0ae26f0b.jpg
http://i66.photobucket.com/albums/h2...n/2bc9c04b.jpg
http://i66.photobucket.com/albums/h2...n/7965442c.jpg


I am going to be traveling the rest of the week for wor so I wont get a chance to do any more for a few days at least. Hopefully this weekend I can find a few more hours.

Things that still need to be done:

-Mount the esc: It should fit nicely behind the lipo. I just need to figure out how best to position it and hold it down.

-Mount the brake servo: As I mentioned I am planning to mount it to the side of the battery tray between the lipo and the front dog bone. There is enough room to fit it no problem, I just need to devise a bracket. I'll probably make something up with the last few scraps of CF angle I have sitting here. I then need to bend the brake lever so I can pull it from the front.

-Install the CC BEC. Not sure where this will get tucked yet, but its small.

-Make a Rx mount. I might make a mount that screws to the front shock stay or Io might keep it simple and just mount it on top of the steering servo. Havent decided yet.

-Figure out how to neatly run all of the wires. That is the toughest part of every conversion IMO. :tongue:

-Glue the tire and wheels. ( I freakin hate that job)

-Paint the body. I was thinking blue and really spending some time to get a really nice job done with a bunch of detail colors, but now I'm thinking I might just go with a solid red paint job and stick to a more tradidtional Carrera color scheme. Any sugestions?


I'll update again when I get some more progress.

:surprised: That thing is gonna rip! :yipi:


:lol: 1/8 makes the Lehners look sooo small!

Looking good, should be a rocket ship!

Awesome work!! Will definitely rip!! :intello:

I agree! That car makes the LMT look small lol

Looks AMASSING!!!!!!!

I think the reason why the Lehner looks so small is because it's actually 1/7th scale :whistle:.
http://www3.towerhobbies.com/cgi-bin...?&I=LXNWX9&P=7

Ahh, that would do it.

I am curious, do Lehners not mind the higher rpm's like the Neu's? Or do they up a bit when hitting the redline?

From my experience they are boyh top notch motors with little to no heat problems. I run a 1940\7 2239kv motor on 5s in my Savage all day with no issues.

the car looks great.. would like to see it run..
phil

I try to keep them at or less than 40K. That seems to be the point where they'll start to become excessively hot during runs. Like my XL 2800 on 4s (42K unloaded) got really hot after about 10 minutes of sprinting. The larger cans may be able to run faster, longer because they can dissipate more heat. Plus, the Lehner motors a rated with a load. Unfortunately, they don't specify what that load is.

Video
 

Well its done. I ran it on Sunday for a test run and got a short video.

When I get a chance in the next couple days I'll post up some proper pictures of the finished car and final conversion details, but for now here is a short video of its maiden run I complied and uploaded last night. I finished up the run by sliding sideways into the curb and cracking the side body post.:whistle: This was a function of severe brake fade. They were hardly working by that point. The stock brakes are not going to cut it. I ordered a set of phenolic disks for the Jammin buggy. Should be drop in replacments and will hopefully reduce the fade. I'm going to double them up. The stock setup has only one disk.

The body on the car in the video is borrowed from another guy that has a DM-1. My body wasnt painted yet and without a body it had no traction what so ever and was almost impossible to keep going straight. Its amazing how much the body matters for on road. Other than the brakes it ran great no issues with the rest of the systems. I didnt really have much room to open it up where I was testing it. I was hardly getting past 1/2 throttle. I seemed to handle pretty well, but I'm really looking forward to Friday night and our regular parking lot oval race and getting it out to give it a good test run, check heats after exended hard run times. Just hoping for good weather on Friday. I'll try and get some better vid then too.

http://i66.photobucket.com/albums/h2...h_7263a265.jpg

I really thought you had it with the nitro engine at the beginning of the movie LOL. Very nice.

I'm browsing through your pictures and I noticed you have an adapter plate on your Lehner. Did you make that?

Mike makes them. Great for keeping the holes on the motor intact. I recomend one for every Lehner.

Nice vid man.

Do you think he might have one that fits the 22 series that converts the 30mm to 25mm?

Don't know if he has one... But I'm sure it would be easy for him to make.