Limitless Yet another GT build

[LibertyMKiii]

Yup, will be taping the front and sides.

It works for the airforce so why not

 

[Dan B.]

Oh shut up This from a guy who makes some of the most beautiful builds is a bit more than I can bear. And you adopting an idea of mine is flattery. The pleasure is all on this side of the table. Trust me.

I'm like the Russian space program of the 60's. The US spent ten million dollars (or however much it was) on developing a ball point pen that works in zero G. The Russians said "Screw you gaiz, vee take pencils!". Low tech solutions to high tech problems.

Thanks bro, I appreciate it.

Yeah, the body mount initially posed a problem I hadn't considered until I was elbow deep into the construction and I wasn't going to reverse course because of something like a body mount. I was dreaming up some wacky scaffoldings in my head to work around where the servo is, yet keep the body posts in their original positions so that I could continue to use the holes that were already in the body.

So I stared at the chassis for a while and after a couple of minutes, I had a stroke. Dunno if it was genius, I don't stroke my own ego that way. That's what I have interns for.

Anyhow, in contravention to how the FC100 was designed to be cut out, I had left the horizontal strip of Lexan at the front of the nose. I run an oversized splitter and I felt like leaving it on would make for a better transition from splitter to the body. What I did was plug the existing holes up front (that doesn't sound dirty at all...yikes...), saw the tips off of two body posts, drill holes in that aforementioned front lip and....tadaaa. My new body mount consists of just two little nubs screwed into the splitter.
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I did take some pics with a full load out after I was done with the reconstructive surgery. The splitter in this pic was the alpha version and proof of concept. The above pictures are the beta release and the v1 CF version should get fabricated in the coming weeks. I'll just enjoy the plexiglass until I hit something. This could be run either as an 8S parallel or a 4S quadrallel.
View attachment 290471

Got batteries?

 

[Tirefryer426]

Was able to run it today on 4s. The big thing I learned is that my road is too rough. I need to find something a little smoother. Or find a smoother stretch of said road. I see the RPM spiking in a few places on power, and then when I'm decelerating its spiking down to zero. That along with the scraping you hear in the video... Says to me that I'm bouncing. I was also running into a headwind. I attempted a second run but had a blow over at 121. Fortunately no damage. Looked super scary, though.
A few notes about this run - This was with the perfect pass springs and I had removed all the fuel tubing. I'm not saying the blow over was the springs. I'm 100% sure that was all on me. I was running the shocks on a lower ride height setting. Inside on the shock tower and outside on the A arm. I was about 2 threads away from maximum compression on the collar. So I've changed to outside on the shock tower, and inside on the A arm to get more ride height, then I'll set the front down a hair with the droop screws so I have more compression on the shocks. See how that goes. If I still scrape then I'll go back to fuel tubing on the front.
Everything else worked really well I think. You can see power draw between the two halves was almost dead even.
I'm going to try a few more runs on 4s. Get the suspension worked out, see if it'll pull 125 consistently and then i'll start moving up.

Video here:

(The distance is long on the GPS because I made a few slow passes to dial in steering trim)

 

[Dan B.]

Looks like you’re well on your way to getting it dialed. Finding the right road can be brutal, man.

 

[Tirefryer426]

Have had some successes and some failures.
First pretty big failure was my first outing with the 908 body. Was trying a new steering config on the 10px using conditions, speed and dual rates. I ran into a really odd behavior with the 10px and steering trims with this configuration. Its a long story, but the end result was that while condition 2 was active, I had almost no right steering. So I start the run, its looking good but the car is working toward the shoulder. I throttle out, car ends up going off the shoulder, the splitter digs into some dirt, car flips and destroys the 908 body.

Some thoughts about this. The 908 body came with a plexi splitter. When the car got into the dirt the splitter immediately shattered, which allowed the body to be pushed to its break point. I'm at least 90% confident that had the front splitter been carbon fiber the body would not have shattered like this. There was no other damage to the car. I'm estimating the car was going maybe 60 when it went off the road. I have one more 908 body and I'm having carbon splitters and spoiler pieces cut now.

I decide I'm just going to get the wrinkles worked out with the C100 body. I figured out what was going on with the configuration - i'll explain that later - I'm curious if anyone else has seen the same thing.

Wind finally died down and I was able to take it out today. Very clean 129mph pass. Bring the car back, check everything over and decide to go for a second pass. 122mph I have a tire let go and the car gets pulled off the road. The front digs into some dirt and I see it go airborne.
Worst damage I've had, but I was expecting much worse. The entire front broke off the Scorched chassis. Batteries ejected from the car, no damage. Body and spoiler had no damage at all. Had a few dollars in broken Arma plastic and I think a crushed bearing or two. The chassis sucks, but the worst part is that Scorched doesn't have any in stock. May end up having to go with the non-full length chassis.

I thought GRPs were good to about 150mph, but it looks like I pushed my luck and should start using foams.

The radio configuration issue I had:
I was using conditions in the radio with condition 2 being steering dual rate set to 30 and steering speed set to 80 input and 80 return.
I have my steering set up with sub trim, and I had my main steering trim at zero. So on the bench everything worked fine.
When I got out to do my run, I ended up kicking the steering trim 1-2 clicks to the left as I was heading to the start. Made my U turn, got lined up and activated condition 2.
What I'd later discover is that for some odd reason, when you are using dual rates and have trimmed your steering to -2, it won't go past zero when you turn the wheel. So I effectively had 30% steering to the left, and 2% steering to the right. The behavior carried, if I kept pushing my steering trim into the negative, it would let me go to zero and no further. I don't know if this is by design... but it doesn't make any sense and ended up trashing a body.

Until the tire issue, both runs were nice and clean. Car felt good, I only got a touch of nose drag under hard braking. Logs look much better and don't indicate I'm bouncing like I was on the first run. I think I'm ready to kick up to 8s and start pushing for 150 after I get a new chassis. Hopefully be back in in a few weeks.

 

[LibertyMKiii]

Ouch sorry to see that.
Hope you stick with it and push through the $$$ pain.

I think many people are waiting to see what someone else can do with the 908 body before pushing to high speeds. Sort of like how it was with the WR body.

 

[Tirefryer426]

Ouch sorry to see that.
Hope you stick with it and push through the $$$ pain.

I think many people are waiting to see what someone else can do with the 908 body before pushing to high speeds. Sort of like how it was with the WR body.

Definitely pushing through. Went ahead and ordered the non full length chassis. Usually takes a bit for Scorched stuff to arrive, so that'll give me a few weeks to clean everything up.

The 908 body is gorgeous. The creator has been awesome to work with. There was some drama with the spoiler they included in the first few packages that went out. I've seen the revised stuff and it looks really good. I should hopefully have photos to share soon.
I know James got one. I *think* Raz got one. I'm not sure who else he sent them to for evaluation. I'm probably going to order four more of them and just see what happens. I'd like to keep one aside as a shelf body.
I think they are looking for a US distributor to help bring the cost down.

I'm really anxious to see what those guys have to say about it.

 

[Dan B.]

Good luck and Godspeed, man.

 

[Diem Turner]

Have had some successes and some failures.
First pretty big failure was my first outing with the 908 body. Was trying a new steering config on the 10px using conditions, speed and dual rates. I ran into a really odd behavior with the 10px and steering trims with this configuration. Its a long story, but the end result was that while condition 2 was active, I had almost no right steering. So I start the run, its looking good but the car is working toward the shoulder. I throttle out, car ends up going off the shoulder, the splitter digs into some dirt, car flips and destroys the 908 body.

Some thoughts about this. The 908 body came with a plexi splitter. When the car got into the dirt the splitter immediately shattered, which allowed the body to be pushed to its break point. I'm at least 90% confident that had the front splitter been carbon fiber the body would not have shattered like this. There was no other damage to the car. I'm estimating the car was going maybe 60 when it went off the road. I have one more 908 body and I'm having carbon splitters and spoiler pieces cut now.

I decide I'm just going to get the wrinkles worked out with the C100 body. I figured out what was going on with the configuration - i'll explain that later - I'm curious if anyone else has seen the same thing.

Wind finally died down and I was able to take it out today. Very clean 129mph pass. Bring the car back, check everything over and decide to go for a second pass. 122mph I have a tire let go and the car gets pulled off the road. The front digs into some dirt and I see it go airborne.
Worst damage I've had, but I was expecting much worse. The entire front broke off the Scorched chassis. Batteries ejected from the car, no damage. Body and spoiler had no damage at all. Had a few dollars in broken Arma plastic and I think a crushed bearing or two. The chassis sucks, but the worst part is that Scorched doesn't have any in stock. May end up having to go with the non-full length chassis.

I thought GRPs were good to about 150mph, but it looks like I pushed my luck and should start using foams.

The radio configuration issue I had:
I was using conditions in the radio with condition 2 being steering dual rate set to 30 and steering speed set to 80 input and 80 return.
I have my steering set up with sub trim, and I had my main steering trim at zero. So on the bench everything worked fine.
When I got out to do my run, I ended up kicking the steering trim 1-2 clicks to the left as I was heading to the start. Made my U turn, got lined up and activated condition 2.
What I'd later discover is that for some odd reason, when you are using dual rates and have trimmed your steering to -2, it won't go past zero when you turn the wheel. So I effectively had 30% steering to the left, and 2% steering to the right. The behavior carried, if I kept pushing my steering trim into the negative, it would let me go to zero and no further. I don't know if this is by design... but it doesn't make any sense and ended up trashing a body.

Until the tire issue, both runs were nice and clean. Car felt good, I only got a touch of nose drag under hard braking. Logs look much better and don't indicate I'm bouncing like I was on the first run. I think I'm ready to kick up to 8s and start pushing for 150 after I get a new chassis. Hopefully be back in in a few weeks.

View attachment 297122
View attachment 297127

Damn, that blows bro. Sorry to see it. I would not have expected the chassis to snap like that. If that were mine, I'd just get some good epoxy and 2ft² of CF cloth and glue that thing up. If you don't know what to do with it...maybe I can give you a hand
I'm no tire expert, but it just looks like the glue bead let go from here. I'm curious about that steering issue. My steering to the right was acting a little restricted, and I'm going through it atm to look for binding somewhere. Cheers for the heads up, I'm going to double check to make sure that it isn't a radio issue. I'll let you know if I find anything resembling what you're describing.

 

[Tirefryer426]

Damn, that blows bro. Sorry to see it. I would not have expected the chassis to snap like that. If that were mine, I'd just get some good epoxy and 2ft² of CF cloth and glue that thing up. If you don't know what to do with it...maybe I can give you a hand
I'm no tire expert, but it just looks like the glue bead let go from here. I'm curious about that steering issue. My steering to the right was acting a little restricted, and I'm going through it atm to look for binding somewhere. Cheers for the heads up, I'm going to double check to make sure that it isn't a radio issue. I'll let you know if I find anything resembling what you're describing.

See, that's where I end up getting myself into trouble with my SO. I've got all the stuff to do that. But then before you know it, I'm making my own carbon sheets. I'm already fighting the urge to get a CNC router. Its wild how it broke. Out of all the crashes I've seen posted here or YT, I haven't seen this. It looks like someone snapped a graham cracker in half. The funny-ish part is that the portion that broke off has nothing connected to it. It broke right at the holes where the aluminum plate mounts that carries the front suspension block. So the car could still drive. I figured once i get the new chassis I'll see if there is any way of converting this one into the short version, but I think it may have broken a little too far back. Maybe I should make an art installation out of all the broken parts.

Now that I have the car apart, I have more questions than answers.
I don't know if I'm 100% convinced the tire caused it. I didn't think the tire looked bad enough, but I pulled a screen grab where it looks quite a bit more mangled than it does sitting on the table. You are right, it does look like the glue just let go on the bead. I know that was solid before the runs. When I started checking over the car I noticed the front was binding and assumed a crushed a bearing. Can definitely feel something binding up pretty significantly on the left side, but once I get everything apart I can't find any evidence of damage. All the bearings spin freely, nothing is bent. No damage to the CV's, drive cups, ring and pinion are perfect. All I can come up with is that maybe a piece of sand or something got in there and then fell out once it was apart.

 

[MLyons]

Please could you post the total weight of the car with and without the wheels? I'm doing some research into developing a new wheel/tyre and it would be an interesting data point to add.

 

[Tirefryer426]

Please could you post the total weight of the car with and without the wheels? I'm doing some research into developing a new wheel/tyre and it would be an interesting data point to add.

The car as it was run weighs about 7.75 kilos without the wheels and tires. The wheels/tires on it weigh 98 grams each.
The car with all of its batteries weighs 9.3 kilos. Its a solid 20lb car on 16s.

Definitely want to follow what you come up with!