LOSI LST XXL Conversion ideas
 

I want a new project and I'm thinking of a LST conversion. I have no experience with LSTs so I thought I would ask first and maybe get some feedback from LST owners. I did a lot of research on many forums and saw a lot of pictures. I also studied the Losi exploded views of the truck but all this is not like having the truck in front of me.

Here's some ideas I have. Tell me if it's possible.

- Can the two chassis side rails be straight? I was thinking of fabricating new rails that are straight making the middle of the chassis as narrow as possible. Why? because I'm also thinking of making a bigger, wider bottom (skid) plate that would stick out on either side to house lipos with either battery boxes or battery straps. This would bring the CG way down.

- With a chassis that is thinner in the middle, could the BL E-Revo tranny be used? Why? Because it's got a very effective and inexpensive slipper and I can easily stuff one of my 8th scale CDs in there which is made with LST parts. The output shafts of the tranny could have Mike's hardened steel drive cups on them to mate with the LST's CVD's.

I'm concerned about the steering components, it's hard to tel from pics or exploded views if my ideas can be done. There might be other issues that I don't know about.
I want to try to make a brushless LST that has a low CG and doesn't require to many custom parts. Two straight chassis rails and a bottom plate are easy to make. The rest I hope could be stock parts from other vehicles that are easy to get or replace if need be.

So thanks for any input on this, I need to know if my ideas are feasible. I don't want to buy a new truck and find out that what I want can't be done.

If you can custom make your own parts this can all be done. The steering would take some work to set up correctly but again, it can be done.

That's encouraging. Thanks.

I'm all for you joing the LST crowd. If you didn't see it - I'm doing the same conversion, and making my own chassis. Bondonutz just did one also (both of our threads are in the General Section). Linc has a thread somewhere here on his, and PinkPanda has one also..... I started out looking to use the Revo tranny also, but have now gone the route of a center diff. I have a brand new tranny if you want it (I think I paid about 40 for it).

We REALLY need a LOSI or LST/Muggy section on here. Seems that a majority of us are moving away from Traxxas based rigs now, and maybe its time this site reflects that a little more......

Same notion here as well. Picked up a LST roller. converting to XXL. Maybe transmission deletion however I want to keep the MT abilities that go along with a transmission. I'll be starting a thread as well once I get stuff in the mail.

So you are basically looking to make a G-Maxx style chassis for the LST? Sounds great! Looking to make a racer or speed truck? Or just a low COG basher?

What you're describing sounds somewhat Muggy-like, with your bottom plate similar to the Muggy's. If so, you could use the Muggy steering parts that would mount right on your bottom plate. (I just converted a Muggy to brushless and love it)

I would go with muggy steering. You idea sounds pretty good, you will have to remake the plates that go between the bulks and the shock towers, as they interface with the top chassis plate. Sounds like it will be strong, but not sure if it will be any better than a muggy (with the better chassis plate).

I look forward to your project. My muggy does turn better than the lst due to the CD, but I really like the std lst for stunts and jumps. Different strokes for different folks, right!

Do you think you can describe the "why" for that statement? Is it based on your feeling that the LST is a little more durable for those stunts and jumps? Or does its geometry give it something that makes it better for that? Just prodding for data......:intello:

agreed!

I have narrowed that down to the lack of a center diff. The muggy is pretty much identical to the lst in the suspension dept. The lst chassis is stronger. And i like the layout of my lst better than the muggy, a bit more weight up front which suits my driving style better. Plus the higher cg makes driving more interesting.

I will say that I have never liked truggies, and the muggy is the only one out of about 6-8 truggies that I have owned that i will keep. Truggies may be good for racing but i only bash and they are a bit boring to me. I like an 1/8 buggy, but that feels completely different to a truggy.

The center diff makes wheelies a little harder to control, and I do not like in flight control as much with the cd. Plus braking is better IMO without the cd. Steering is not as good, but my bash area is not too tight, and I can always drift on power or brakes to turn a bit tighter.

I still like the muggy, and currently it is assembled so it gets played with more often.

I will have to second that idea. Experiencing front wheels unloading while in a wheelie is horrible and usually ends bad, for example.

The LST is a MT, its big, 4WD and tough! I much rather full time 4WD for bashing, crawling, traction, and fun!

I wonder how the muggy would be with the center diff locked, i wish i had saved the locker from my Cen gst.

A low CG basher would be what I am hoping for. I raced for a lot of years, off road, onroad, 1/10, 1/8, nitro and electric. Right now I really like the fun I have with MTs but since the MT race class is dead around here, I only bash. But the racer in me loves to bash with a good handling MT. When it handles like a racer, it is just more enjoyable to me.

I planned on making new plates out of CF so no problem there. There might be a couple more parts that I would like to replicate in CF. It might not make the truck stronger but it might make it a little lighter.

Thanks for all the replies, I will look at the Muggy steering as a good option to what I hope to do. I just need more funding for this project. Might take a while.

Funding... Just sell a kidney. Or your balls, they go for at least 150k for a working pair.

Sperm bank.....

I'm too old, they won't take my sperm. My boys are fine where they are, they are enjoying the rest after many years of abuse. :lol:

Been trying to make a few drawings of what I want to do but it's kind of hard without having the actual truck in front of me. And I'm doing this in the middle of packing boxes because we're moving in three days. Anyway, here's what I have for now. Many adjustments and modifications will need to be done once I get the truck and I can physically check if things will fit. From what I have now, the size of lipos would be limited. I would try to fit the Losi Muggy steering bell crank in there, secured to the bottom plate. I would like to use the E-Revo tranny but it needs to be positionned to the front a bit so I don't know yet what to do about the center shafts.
I thought of making the top plate out of 3 mm CF, the bottom plate out of 3 mm thick T6 6061 aluminum and the rails from Delrin blocks if I can get a supplier from the web. I would need to buy a new tool to make the rails, a band saw. Been wanting a band saw for a long time and never got around to buying one. Here's some pics.

Lower plate
http://i177.photobucket.com/albums/w...sis_plate1.jpg

Upper plate
http://i177.photobucket.com/albums/w...sis_plate1.jpg

Rails
http://i177.photobucket.com/albums/w...sis_rails1.jpg

Bonus pic
http://i177.photobucket.com/albums/w...l_concept1.jpg

Here's a second concept with straight chassis rails that should be much easier to make and separate front, middle and rear skid plates that overlap each other in the middle. I made it into a little movie.

http://i177.photobucket.com/albums/w...l_concept2.jpg

Looking good so far. I should have those XXL dimensions for you in a couple days.

So now your only solid piece front-to-back will be the upper plate. Everything else is in three sections. I'm not sure, but will the CF plate be able to bear the brunt of the forces, or will it be a weak point?

Here's my thought: You could make the lower plate a single piece Al plate from front to back, but more narrow than your present center section (just as wide as the widest parts of the top plate. Then you could add CF "wings" in the middle as battery trays. If that makes sense.

JThiessen, thanks, it will help a lot.

brian015, yes what you explained made a lot of sense. This last concept was to try to have simpler chassis rails, they are basically bar stock cut to size and drilled in the right places for screws and bolts. They would be so easy to make and so much cheaper in price for the raw material. A solid one piece lower plate was in my first concept but I thought that having a separate front, middle and rear is also interesting. The front and rear plates usually wear out faster than the middle, when they need to be replaced then you don't have to replace the whole bottom plate. Even though they are separate, they do overlap each other which brings more stiffness and strength to the chassis as a complete unit. Also, I plan to use long M4 screws that go through the bottom plate, the chassis rails and the top plate with a lock nut on top to sandwich everything together and lock every part as strongly as possible. I'm still just playing around with ideas so keep on giving your feedback, it will definitely help me to come up with a final concept.
And please tell me if you see anything that couldn't possibly be done because I still don't have the truck, I'm just figuring out stuff just by looking at pics from other builds and exploded views.

Since you and I are doing the same thing right now, some details that I see as tough to overcome:
1) Replacing the rails. The rails taper up and in the back on the bottom (I believe the front is just a taper inboard). This taper interfaces with the bulkhead support/mounting plate. Nailing this part down will be tough via reverse engineering. Not impossible though. This is the only reason I have chosen to keep the stock rails.

2) I also think the three part chassis might prove to have too many joints over time. I really think that having a continuous member from front to back is very critical to the flex and structural rigidity of the chassis.

If you are going to make a one piece bottom chassis, you could keep it flat to avoid the the taper issue. Or, get a muggy chassis and mod that to your needs.

MC - check my thread. I put up some new pdf's of the plates for ya. http://www.rc-monster.com/forum/show...781#post355781

Thanks JT that's great.

Alright, a front and rear skid plate, overlapping a center bottom plate, with two ''one piece'' chassis rails and a top plate with XXL specs. I can't wait to get the truck to see if this is doable.

http://i177.photobucket.com/albums/w...s_concept1.jpg

Those one-piece rails are going to be your most difficult fab work. I wonder if they're worth it. The weak point in your three-piece lower plate is obviously at the joints (and what you said above about sandwiching all four layers at that point with M4 screws sounded semi-convincing to me :wink:). And it's at that weak point that your one-piece rails have their kinks. I'm not sure that turning your previous three-piece rails back into one-piece rails is going to add any rigidity to the chassis. I imagine the kinks in the rails would allow the rails to bend up and down at that point (where straight rails would not). So, I don't know if it's worth all the effort to make them.

Those are my thoughts trying to imagine how it would work when stressed - I don't think the one-piece rails would be a great advantage over the three-piece rails in reducing the stress on the CF top plate.

My vote: try your previous plan (3-piece bottom plate and rails) and if it fails go for a one-piece bottom plate.



So - when are you expecting to get your truck? (or is this just an elaborate thought-experiment? :lol: )

Look at your chassis from the side. Now imagine a load being applied from the top. The chassis will bend downward in the middle, forming a "U" shape. With a solid piece running from front to back, the stresses in the chassis are linearly distributed through the member. When you have changes in shape, those stresses are passed through the most direct path. In your case, it will be through the fasteners and the holes for the fasteners. Now remember, you are looking at it from the side....you only have a single fastener line when looking at it from this direction. All those stresses are going to be passed through that fastener, and the thickness of each SINGLE piece of material. I'd predict an immediate failure - first at the bottom most piece - it will try to pull the fastener forward though the hole. The fastener being harder, will tear through the aluminum. Give your self at least two fasteners at each joint when looking at it from the side, maybe three.

For now, it's just trying to come up with a nice electric conversion that looks factory made. I really want the LST, when will I be able to get it is unknown :neutral: We just bought a new and bigger house and we are still unpacking from the move three days ago :yes: Lots of work to do around this house but I still want to squeeze this truck in.
As for the three piece bottom plate, it is no different than the stock truck, the XXL uses a rear and front skid plate and a middle one that are not touching each other as far as I know. They all look separately secured to the chassis rails. What I show in the last movie are three bottom plates that overlap each other to form a flat bottom. This is because the center plate would be lower than the stock one. At the same level with the front and rear plates. The center plate also houses the batteries so the lower it is, the better for a low CG.
With the help of a band saw, the one piece chassis rails should be fairly easy to make with a bit of planning. The hard part might be to find the raw material to make them at a reasonable price. I still don't know how high the stock chassis rails are, if they are 1.5 inches high or less, I should be able to find material to fabricate at a good price. If they are higher than that then I might have some difficulties.
Thanks for your feedback, I appreciate it.

On the stock chassis, the plastic rail and the top plate do all the load carrying. The center plate keeps the lower rails from spreading apart when a load is applied. The front and rear skids aren't part of the equation.

The stock rail is something around .983 thick in the center - I havent measured the ends. Probably somewhere around 1.25" or so.

I went back and looked at your vid again. For some reason, I thought that your center rails were three piece.....sorry!

What CAD are you using? I might be able to send you my CAD files.

I'm not using CAD, I draw to scale with CorelDraw and then export the drawings in jpeg to make the little movies. CorelDraw lets me export whatever I drew in a lot of formats including DXF and DWG AutoCAD files. If you want to send me your CAD files I can just download some free CAD reader off the internet to see them. Once I see the measurements, I can duplicate the part in CorelDram but only in 2D. Thanks.

Ray
raymondduchesne@sympatico.ca

Nice to see some LST conversions. I just posted a large reply but the sight timed me out. had to log back in and it lost it!!!!!!!!!!!!!!!!!!!! I have a lST that I converted a year ago. I would like to upload some photos for you all to see. I don't know how?? I would be happy to answer any questions about my build. I have converted 4 vehicles to brushless so far. Happy with all of them. Crashed my 6 cell revo 3.3 conversion yesterday in to a table at a cook out. Broke the left front steering knuckle and stripped the delrin spur gear and broke the front bumper mount. That the fun part rebuilding it even better.

This is mine, only a motor mount and a lot of imagination...

http://i361.photobucket.com/albums/o...y/DSCN4351.jpg

That LST looks really nice. I like it a lot. Is that battery tray custom made? It looks great.

We know you like the pink strap too! :lol:

I would probably get a black sharpie and color that battery strap and pink rear shock socks. :mdr:

Yes, two pieces of aluminum, two tubes with a M3 rod inside (everything wrapped with Heat shrink tubing).

The weight balance is perfect instead of the new losi kit.

I won an auction for a brand new and complete LST XXL chassis. When I get it, I will study it and have a better idea of what needs to be done if I go ahead with this build. We need a LST forum in here so that if I do the build I can post it in there and bring some more attention to myself :lol:

We all are small attention wh*res:lol:

It´s really nice to see a new project from you MC since your Erbe project is as near as "done" goes:party: It´s a shame tho that a proper LST forum doesn´t exist:neutral: Can´t wait to see your build:whip:

I received the XXL chassis a couple days ago and had a chance to look at it closely. I really like this chassis, the way it's done, the way it looks and how stiff and strong it is. I'm not sure I want to change it as much as I wanted to before. So here's another idea to convert with a low CG. This idea would be very easy to do, just a new middle skid plate in 3mm CF, a new upper main chassis plate in 3 mm CF and a couple straight blocks for the new middle skid plate. Then there would be the battery covers I would make with 2 mm Kydex.
The lipos would be on their sides instead of flat. I chose to limit the size of lipos on their height to 35 mm so that the truck doesn't become too wide. There's still room to go a little wider though.
I put the E-Revo tranny in the center of the truck so it would use the same length middle shafts front and rear. I also put the motor up front with the ESC and receiver box.
The whole thing would be 200 mm wide and it would fit inside the XXL body.

The middle skid
http://i177.photobucket.com/albums/w...tom_plate1.jpg

The upper main chassis plate
http://i177.photobucket.com/albums/w...per_plate1.jpg

a view from the top
http://i177.photobucket.com/albums/w...l_concept3.jpg

a view from the side
http://i177.photobucket.com/albums/w...cept3_side.jpg

a front view of the battery space
http://i177.photobucket.com/albums/w...cept3_batt.jpg