Mid motored Cougar 2(ish)

[yorak]

I made some progress! Before I lose steam (again) I'd thought it would be cool to share it with you guys. I really love building custom parts, but boy it takes a lot of time to get them right. It seems no matter how many times I measure, the cuts keep going wrong..

To take a step forward, sometimes you need to take few back. So, off you go parts...



I made three motor mounts, one out of plywood to get the measurements in, one out of random plastic sheet to try to properly mount the motor and, finally, one out of aluminium sheet. Combined with some creative hammering of the chassis with a steel pipe I got few mm of extra room necessary to fit the hardcase Lipo AND the the motor at the same time. There is not awfully much room to adjust motor position, but at least I can choose between few different pinion sizes.



For now I decided to ignore the fact that the motor spins the wrong way to be a proper mid-motor conversion (please see my discussion with mr ED, above). However, I made sure there is room for another shaft that would accept the slipper and transfer the power to the shaft running the belt pulley. The slipper assembly would be mounted a little higher and one could then switch the spur gear without removing the entire gearbox assembly.

I ran out of hobby time, so I was not able to put it back together just yet. I also need to sort out the steering turnbuckles and few minor details here and there. I can see the project nearing completion, or, at least my Cougar 2 buggy with Traxxas Bandit and nitro 4-tec donor parts would be in some kind of running condition. I think projects like this will never be truly completed.

To be continued...

[eugine]

Hello.
Any news of this great project ?

[Lonestar]

I'd love to see pics... you've likely hotlinked them from another forum, which doesn't allow hotlinking - it just says "image" instead of showing a pic

Edit: I can see they're on dropbox from the URL... I just can't see the pix themselves!

[yorak]

Any news of this great project ?

I'd love to see pics... you've likely hotlinked them from another forum, which doesn't allow hotlinking - it just says "image" instead of showing a pic
Edit: I can see they're on dropbox from the URL... I just can't see the pix themselves!

Thank you eugine and Lonestar for the continuing interest to this project. I've been able to put the car back together and decided it would be a good time to take and post some new pictures. Related to the pics Lonestar, the Dropbox hosted images show up properly with all of my devices, but I've now attached them to this (and previous) posts. I'd be interested to hear if others have problems of images not showing? Also, for those interested, there are more photos of the current state of the project available in my Dropbox album.

The status of the project is that this unholy Traxxas / Schumacher Cougar 2 frankenstein of a buggy is in driving condition . Note: not racing, but in driving. This is currently not a problem, because lately I've been building the buggy with my 5yr old daughter and I've been motivating her by saying we are building it for her. So, the parts do not currently have to endure huge speeds nor the drivetrain ridiculous brushless power. The prototype custom parts made from random plastic pieces from my materials bin should do for now.



I installed some random electronics I had laying around. An ACOMS AS-12 servo, 27T stock brushed motor from the '90ies, and a cheap Chinese 10A ESC to drive it. I checked with a multimeter that the amp draw from the motor seems to be low enough with conservative gearing, but I did glue an heatsink to FETs to help to keep the ESC alive.



Unfortunately, the winter and snow here in Finland prevents proper shakedown testing. There is an indoor track which I've been planning to to visit it this winter, but it's some 100 km away. However, if we are able to go there, I'd like to take some video footage on how the buggy behaves with the moderate electronics currently installed.

I have some future plans and upgrades for to take the "C2KF" to the next level:

• Drill the steering levers to fit small bearings. I'm currently using short pieces cut from a brake line there because I did not have spare U749W steering pivot bushings. However, there is quite a lot of slop causing, e.g., bizarre effect of varying bump steer. Again, not a problem at the current speeds, but if I ever wish to properly race this thing getting rid of the slop is a must.

• Purchase more contersunk hex hardware. Currently there is some buttonhead screw ends sticking out of the bottom of the chassis, and it is not good.

• Cut the rear shock tower and steering rod out of FR4 (they are currently made of soft and brittle plastic).

• Fit longer inner telescope drive shaft halves. I'm currently using the 4-tec ones and they are way too short to handle any serious amount of torque.

• Replace the differential pulley and driving pulley as they are rather worn out. While at it, also replace the drive shaft with a one that allows adjusting slipper with a nut instead of inserting spacers.

• Make a new motor plate that takes two shafts and gears. This was discussed earlier with DennisM and Mr ED and the idea would be to allow rotation of the motor to push the rear wheels down instead of the front wheels as it is done in a modern mid-motored buggy with a 4-gear transmission. At the same time I'd be able to swap the last undersized 8x5 bearing in the powertrain to 10x5. As and additional advantage this would allow changing spur without removing the entire gearbox assembly

Til next time.

[yorak]

For the improbable scenario that someone would like to build something similar (get help ) I composed ad parts list. It does not include easy to find hardware like screws, nuts etc., but all the major parts should be listed.

For Schumacher Cougar

• 1 x aluminum tub chassis (preferably already ruined, as one will have to cut the tail off)
• 3 x T1129 rear wishbone pivot blocks
• 2 x T1131 rear wishbone pivot pins
• T340 & T341 steering levers
• 1 x U775 front bulkhead
• 1 x U322 lower front suspension plate
• 1 x modern Schumacher turnbuckle pair 45 mm (part number?)
• 1 x U797S Schumacher turnbuckle pair 35 mm

From Traxxas

• TRA5827 Slash 4WD battery hold down strap (cut to length and doubles as top deck) and the post/retainer (dremeled used as mid-bulkhead)
• TRA3640 suspension screw pin set (only front)
• TRA2531X Bandit front supension arms
• TRA3736 steering blocks
• TRA2432 Bandit caster blocks
• TRA3654 wide wheel 12mm hexes (pair), used at front
• TRA1654 narrow wheel 12mm hexes (pair), used at back
• TRA1651 Bandit half-shaft driveshafts
• TRA2753X rear stub axles
• TRA3637 front stub axles
• TRA5460X anodized GTR shocks (4) with Jato front springs (e.g. 2 x TRA5427)
• TRA4280 electric 4-tec alloy housing ball differential with TRA4255 steel output yokes, but I guess any diff would do (e.g. Nitro 4-tec diff)
• TRA4824 Nitro 4-tec gearbox side plates (dremeled to fit)
• TRA4896 Nitro 4-tec pulleys and TRA4865 drive belt
• Slash 2WD slipper clutch with 86T spur gear fitted on Nitro 4-tec input shaft (not optimal, see below)
• TRA3993 E-maxx input shaft with older style Traxxas slipper assembly with friction pegs (this upgrade is listed, but not yet done)

Misc

• 1 x X-Factory X6 XF3012 rear A-arms (pair)
• 2 x HPI 85037 rear hubs (4)
• 13 x HPI 4.3 mm ball studs
• 12 x RPM 73381 Heavy Duty 4-40 Rod Ends (White)
• 1 x RPM 70062 Servo Mounting Posts
• 2 x 35mm turnbuckles from the TQ Racing 04024 Turnbuckle Set (Schumacher ones would be fine, but I did not have those)
• Random ball cups, ball stud with tiny M2 thread, turnbuckle and servo horn for steering linkage
• 12 x 5x11x4 rubber sealed bearings

Custom

• Replacement for Cougar steering rod (from U749, part number?)
• Front cross member to mount the battery holder post on
• Rear shock tower
• Gearbox top cover
• Aluminum motor side plate
• 2-screw hold pivot block for the front mount of the rear arms

[eugine]

You did a great job with that car !
Oh yes please do some videos of this blitza when you will come to the track.
And it is a very good idea to share the part list you used.

Thanks Yorak to allow me to dream

[Mr. ED]

http://www.rcmart.com/venom-vm00361bl1-belt-drive-gear-411148-black-p-69796.html

Don't underestimate a 5 year old girl. I'm sure she can hit more than you imagine.

[Lonestar]

I just love this kind of work - very nicely thought out

[yorak]

You did a great job with that car !

I just love this kind of work - very nicely thought out

You are too kind. And, to be honest, surprisingly little thought went into the bulid. The design was more driven by pure randomness of the leftover parts I had available . I just had to be a little creative on how to put it all together.

Funnily enough one of the hardest parts was to find a suitable set of rear A-arms. Internet does not oftentimes tell the measurements of the arms, so finding a pair with right width and length took a lot of trial and error. I think I have 4 or 5 rejected pairs of rejected rear A-arms in my box. I just hope those do not spin off into similar projects.

http://www.rcmart.com/venom-vm00361bl1-belt-drive-gear-411148-black-p-69796.html

Interesting, really interesting. Thank you Mr. ED for the link. I'm tempted, but as I already have the parts I think I'll try go with the gears first. I'm planning to use separate aluminium bearing carries, which makes it easy to try drilling the holes for the two axles many times to achieve an optimal gear meshing. Currently life is again quite hectic, but I'll post here if I manage to get the "4-gear" beltbox to work.

Don't underestimate a 5 year old girl. I'm sure she can hit more than you imagine.

Oh, fortunately she is quite careful driver. And with the speeds the 27T brushed stock motor goes when fed by 10A ESC there is little chance for major damage. What I've learned from racing my runner Cougar 2, is that it is the LIPOs and brushless power, and the speed and crazy jumps of modern tracks that break the parts. This makes driving vintage buggies expensive. Also, breakage is oftentimes showstopping as one has to try and hope to find the replacement part from eBay.

Also, Traxxas cars have a reputation to be nearly indestructible, and the parts are cheap and easy to find. As can be seen from the parts list, quite a lot of the parts are from Slash / Bandit chassis. The battery strap doubling as top deck should keep the chassis pan unbent. However, what I'm most worried with the "C2KF" is the suspension plate U322. I dont know if it is the age of the plastics or my poor driving skills but I seem to have broken quite a few of those

Regarding next steps: Some years ago I made a mold Cougar SV style body that would fit a vintage Cougar, just for laughs as SV was new back then and I sometimes took part to local races with my vintage Cougar which caused some confusion. The idea was to confuse people even more. I have one clear pull left from my experiments. It's not perfect, as the PETG plastic is too thick and the mold should've been smoother, but at least the one I used with my runner for some time looked OK.

[Mr. ED]

Those are some serious air intakes!

[eugine]

You are too kind. And, to be honest, surprisingly little thought went into the bulid. The design was more driven by pure randomness of the leftover parts I had available . I just had to be a little creative on how to put it all together.

That's a real challenge, to fit all that together ! Congrats!

Regarding next steps: Some years ago I made a mold Cougar SV style body that would fit a vintage Cougar, just for laughs as SV was new back then and I sometimes took part to local races with my vintage Cougar which caused some confusion. The idea was to confuse people even more. I have one clear pull left from my experiments. It's not perfect, as the PETG plastic is too thick and the mold should've been smoother, but at least the one I used with my runner for some time looked OK.