New hi-speed project - Page 17 - RC-Monster Forums

BrianG · 04.10.2008, 11:08 AM

Actually, yes I did think about poly/lexan as an option. Whatever I use I plan on bending the edges for a little "kick-up", which should help stiffness. However, this tray will not be supporting any weight (I have other ideas for that), but I want stiffness to prevent flexing with the undercar air currents. It's just hard to beat aluminum for cost to weight to stiffness ratios.

What's_nitro? · 04.10.2008, 11:13 AM

That's true about the aluminum being "financimechanically" efficient! I had some 3mm 7075 T6 when I made that tray but I have other plans for it.

BrianG · 04.21.2008, 09:44 PM

Another small update since I can't afford ~6 bills for lipos right now...

Made new dirtguards. Primary goal was to cover as much of the bottom as possible to help prevent air turbulence, and to allow room to mount the gargantuan lipo pack whenever I decide to get it.

Image showing the old vs new for a comparison.

And one with them mounted on the chassis. They're not painted yet because I may be doing more work to them.

lutach · 04.21.2008, 10:13 PM

Looks very good.

BrianG · 10:17 PM

Thanks!

They're surprisingly strong for the thickness (1.6mm). I was thinking about using some additional supports for the lipo pack since they will overhang the chassis by quite a bit, but I don't know now. I'm thinking the new dirtguards coupled with the rigidity of the battery tray may be sufficient...

I'm glad I didn't use fiberglass because it would have been at least twice as heavy. The prototype guarg I made with fglass was quite a bit heavier than the Al ones and it wasn't even as big...

suicideneil · 04.21.2008, 10:20 PM

Feck me....

Normally Brian, the control surfaces of wings go on the trailing edge....

lincpimp · 04.22.2008, 01:36 AM

Looks spiffy Brian! Nice work.

I have not had much wheel time on the mbx/gtp conversion I did due to shock issues. Could you tell me how long the from and rear shcks are when extended? I was going to use revo shocks on mine, as I had a spare set of 4, and maybe fab a set of shock towers...

BrianG · 04.22.2008, 02:00 AM

@neil; yeah, I guess I put them on backwards eh? lol. Seriously, I was shooting to keep the air under the car (not in the car) and as streamlined as possible.

@linc: Thanks! Without measuring, the fronts look like they could be replaced with Revo shocks with not much issue, but the rears are about 50% longer and would definitely need a new shocktower. Instead of fabbing a new tower, how about just getting another front tower and putting that in back? Of course, you'd have to figure out a new body post mounting scheme...

lincpimp · 04.22.2008, 02:04 AM

Quote:

Originally Posted by BrianG

@neil; yeah, I guess I put them on backwards eh? lol. Seriously, I was shooting to keep the air under the car (not in the car) and as streamlined as possible.

@linc: Thanks! Without measuring, the fronts look like they could be replaced with Revo shocks with not much issue, but the rears are about 50% longer and would definitely need a new shocktower. Instead of fabbing a new tower, how about just getting another front tower and putting that in back? Of course, you'd have to figure out a new body post mounting scheme...

I thought about that, but I may just make a new shock mount that bolts to the exisring shock tower. I do not see any reason that the revo shocks will not work, they have plenty of travel for an onroad car. I am wondering what springs to use. What are the softest springs for the revo? (color of the band?)

BrianG · 04.22.2008, 02:06 AM

Here are your options. Looks like yellow (2.6 rate).

BrianG · 04.22.2008, 02:40 AM

I just quickly checked a Revo shock. A fully compressed Revo shock is the same length as a front GTP shock at about half travel. When the GTP shock is fully compressed, the Revo one would bottom out and then some. You'd need to fab a new front tower to use the Revo shocks.

The back is about 40-50% longer than a Revo shock, so that won't work either without mods.

lincpimp · 04.22.2008, 04:02 PM

Quote:

Originally Posted by BrianG

I just quickly checked a Revo shock. A fully compressed Revo shock is the same length as a front GTP shock at about half travel. When the GTP shock is fully compressed, the Revo one would bottom out and then some. You'd need to fab a new front tower to use the Revo shocks.

The back is about 40-50% longer than a Revo shock, so that won't work either without mods.

I guess that I will fab up some top mounts that will place the shock in the correct location. I want a bit of downtravel, I will setup the car to ride with the driveshafts parallel with the ground. At least this way I can retain the stock shock tower and just add a mount... hope it is that easy!

aqwut · 04.22.2008, 03:16 AM

Holy Cow..!! I can imagine how many Lipos you're going to have in there..... AWESOME!!

BrianG · 04.22.2008, 03:19 AM

The plan is for 10s ~5Ah. Something with a high discharge to drive the 1515 2.5d (kv=1650).

JERRY2KONE · **These -** 04.22.2008, 09:25 AM

I would guess you need something like the Thunderpower 10S/5K/V2 packs with 25C continuous, and 50C burst output, for $549 a piece. WOW that is some power, but at a huge price. The chassis is looking good BG. It does look kind of freaky being so wide, but with the right aerodynamics and some down force wings installed that thing should move pretty quickly and hopefully stay on the ground. It will probably do very well if you can get some ground skirting to keep the air out from under the vehicle. Good work BG and good luck.