I am racing on low traction dirt and I an trying to make my mid motor handle better than all of the rear motor cars at the track. I tried rear motor and hated the feel. I realized that the problem was the high moment of inertia, and started this project.

I have learned that in theory mid motor is superior to rear motor if weight is kept the same, because of moment of inertia and the rotation of the motor planting the rear tires.

My mods have worked and I love the feel. I am now just making minor changes and experimenting with things to see the effect.

Ok I think now I understand better. I was not considering the inertia moment on the right axle... So if we keep the mass centered at maximum (on the axle front-rear but also on the axle right-left), the car will rotate faster in tight corners... Very interesting... I will study the behaviour and the installation of others Losi racers next time...

Thank you for your explanation.

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Its not just in the corners its everywhere. In the air, rough areas of the track. The big one I am noticing is how much better the mid motor plants the rear tires, this makes sense when you think about the motor rotating the tires into the ground as opposed to lifting the rear tires as does rear motor.

I have been working on some stuff, nothing major yet but I have some ideas on centralizing the mass even more. I am going to try getting the rear shocks in front of the rear drive shafts and a few other ideas I want to test. But, more on this soon.

Everything came screaming to halt on this project. I moved, you know how that goes. Setting up my hobby room soon and getting started on my projects again. And I have a new one, focusing on aero, its a super light 4wd scte. Thread coming soon.

Its been a while..... Life's hard! New job and other projects are keeping me busy. Recently I started screwing around with my 22 again. I spend a lot of time thinking of ways to centralise the mass even more. My goal is to get rid of the rear brass weight and I would like to experiment with a laydown tranny and see if I can get that to work in low traction situations. With that in mind I did this next round of modifications to see how far back I could get the CG in anticipation of a laydown tranny.

First, this is the apex of the development I did on the last round of modifications.



Everything is pretty much the same as before but with a couple of little changes. I got the Novak Impact in the car, much smoother. I also got the shocks on the front of the arms, again to centralise the mass.





I had to move the shock tower forward a little bit to get the shocks close to vertical. You can also see the diffuser that I stared to experiment with. It turns out it was kind of the jumping off point for the next stage of development / testing.



After some careful measuring I re-located the camber link to the front of the shock tower because moving the tower forward covered the holes.



Its a close fit but it works!





For a while I have been looking at the arms on off road cars thinking there was a huge opportunity there for aerodynamic gain. I did some testing with my SCTE and a students HPI Blitz and found huge gains. I am now transferring what I learned over to this project. These are "arm mud guards" and wings. I haven't finished or tested this yet.



Well this was about the time the car went under the knife to test a number of new ideas!



I am going to try a couple of air plane wing servos wired in at 7.4v. Both have around 65-75 oz/in of torque. That should be enough for skinny 2wd buggy tires.



Originally I thought of putting the ESC on the side of a laydown tranny but for this test I thought I would try it on the end of the motor. Shouldn't affect cooling, might cause other problems...... But that's why your test things.

You can see the receiver on the side of the tranny.



Decided to use the Spektrum wing servo because of its aluminium case. I also removed the side pods and installed Delrin chassis braces. I designed these to be able to adjust the amount of chassis flex by adding or removing screws.



After my parts came in I started to finalise the design. The focus is on centralising the mass and aero. So the chassis is narrowed and I am starting to channel air to key areas. Again this is the first iteration and I am sure it will change drastically before it is all done.

Everything got mocked up in cardboard.



I got my new J concepts body and cut the side pods off for air slow to the rear arms.



I am also going to try out the LRP super shorty to make the chassis narrower for aero.



I got a carbon front shock tower and cut the brace joining the two sides together off. I did this to make the front wing more effective. You want to make the airflow under the wing as fast as possible to create lower pressure and more downforce.



Now that I had everything mocked up and was sure it would work I got to work narrowing the chassis. But..... My band saw still needs to be restored (I found a cast iron bench top 1960's band saw for almost nothing, it just needs to be restored) so I made a DIY band saw. I took my Jig saw and stuck it in my vice upside down. It actually worked pretty good for being super getto!





After a little filing.





I then started transferring the cardboard templates to lexan.



And started bending it up.





Once again I have to say this is all experimental! I think the side pods / floor
are a little to large and will probably be cut down to prevent kiting. The cover attached to the gear cover are the former side pods.

The canards attached to the side of the front window is also something I am going to experiment with. Fortunately these are bolt on, so they are easy to remove.



Everything pretty much fabricated.







Here you can see the battery slot. All the pieces still need to be sanded before paint.

I didn't spend a tone of time on the body because I am not sure how it will work. Once the design is finalised and the aero is fully developed to my satisfaction I will make it pretty. But at this point I have a bunch of stuff I want to try.



The body with the side pods removed.



A closeup of the window canards. I have made these adjustable!



Next I got started on the wiring, shortening and laying out all the wires.





All done and tucked! The positioning of the electronics turned out awesome.



I also made a new battery hold down.

The only thing I don't like is the color of the LRP battery!


I've got the steering done, but no pics yet. Might weight until everything is painted. But soon I hope.

I personally love experimenting more than anything else. Don't worry about naysayers or even rules. Test your ideas and find out if they work or not. That's how you learn.

Have you seen hobbyking's super shorty?

http://www.hobbyking.com/hobbyking/s...arehouse_.html

Very much this.

You realize putting the shocks on the front of the tower moves weight off the rear axle, and it looks like every other effort you make is to put weight ON the rear axle.

Where'd you get your engineering degree from?

Read the 2nd paragraph of the 1st post!

I admire people thinking outside the box

Yah I have seen it. But I wont run Hobbyking, I've seen a few blow up.

I'm not an Engineer, I'm a high school shop teacher..... But thanks!

To answer the other my point is to centralize the mass and play with weight distribution front and rear. So far I have learned that I like about 67% rear bias on dirt and up to around 69% if the traction is really low. This makes the front tires just dance but not wheelie. And the more I centralize the mass the easier the car is to drive and the faster it gets. The results are shocking!

So now I am experimenting with aero and centralizing things even more.

I'm on holidays and haven't posted pics lately but wanted to give you a little seek peek of were I'm at!

I've ordered some new parts. More to come soon. I might be building a purpose built carpet car with some mad aero!