HV Savage

[MetalMan]

I thought I had a thread on this truck here, but it turns out it was on the temporary forums. Here's the old setup:

http://www.rc-monster.com/tempforum/...2&postcount=27
http://www.rc-monster.com/tempforum/...4&postcount=28
And a vid of the old setup:
http://video.google.com/videoplay?do...45575189089257

The chassis is an extended low CG chassis from FLM.

Since I just received my HV110 back from CC, this truck will live again. But since that 12XL's rotor broke apart, the truck needed a new motor. That's where the KB45 10XL (1200 kv) came in. The motor plate had to be modified due to the 30mm bolt pattern and 4mm mounting screws.
I remade on of the brake linkages, so now the brakes are stronger than before, which is nice considering the weight of the truck.

New pics will be up soon.

[suicideneil]

I remember this- that was a sweet setup.

[MTBikerTim]

Nice. 10s A123 is crazy. I was watching your yard jumping revo video as well. The handling on that revo is impressive. I'm starting to understand why you guys like them so much.

[MetalMan]

Heh. On Sunday BP and I went out bashing, and I took the Savage along with me. At the end we did some speed runs, and I gotta say, the Savage's suspension is way too soft for its intended purpose (especially without sway bars). On one pass, I kinda lost control of it, and it smacked a car tire... At least there were other spectators! The damage was pretty minimal considering the weight, and the 45+mph speed it was going. One of the CVD axles broke where the hex goes, a couple shock shafts bent, and some stuff came loose (like the batteries). Not too bad, I think!

[MTBikerTim]

Hardening the shocks up works well but if the truck isn't lowered it will want to flip really easy. A cheap an nasty way to lower them I have seen is a couple of cable ties. They harden the suspension and lower the truck at the same time.

[MetalMan]

Actually, the suspension does its job very well. It's just not stiff enough. I can't get the truck to flip/roll/whatever AT ALL, and I think it's low enough. The LST shock upgrade/mod is looking pretty interesting, though...

I'm thinking this truck will be better off as a basher. After all, that's what the Savage was made for. It could still be converted over to speed run usage easily for future events.

[BP-Revo]

So are you indeed converting it over for bashing?

You need to pick up some sort of vehicle with mechanical brakes that you can fit the KB45 in...I'm sure in a truggy and something along the lines of 12S A123 and you can come very close to 100mph...

[lincpimp]

Originally Posted by MetalMan

Actually, the suspension does its job very well. It's just not stiff enough. I can't get the truck to flip/roll/whatever AT ALL, and I think it's low enough. The LST shock upgrade/mod is looking pretty interesting, though...

I'm thinking this truck will be better off as a basher. After all, that's what the Savage was made for. It could still be converted over to speed run usage easily for future events.

How is the startup with the cc hv esc? I just bought a hv 85 for my aftershock conversion, so I guess that I will find out for myself!

[MetalMan]

Originally Posted by BP-Revo

So are you indeed converting it over for bashing?

You need to pick up some sort of vehicle with mechanical brakes that you can fit the KB45 in...I'm sure in a truggy and something along the lines of 12S A123 and you can come very close to 100mph...

Yeah, I think I will. It'll get more usage that way.

If only I were made of money...

Originally Posted by lincpimp

How is the startup with the cc hv esc? I just bought a hv 85 for my aftershock conversion, so I guess that I will find out for myself!

With the gearing the truck is running at, the startup is very good for an airplane ESC, and good in general IMO. I don't do fast starts, though, so as to reduce the amp draw and the overall stress on the ESC (I've already burned one). Once the gearing is changed for 40-45mph, I imagine the startup will only get better. At the same time I'll also switch over to 10s1p A123 instead of the current 10s2p. Should be good for a 2lb. weight reduction.

[MTBikerTim]

MetalMan your setup is sounding pretty good to me at the moment. 10s1p A123 pack isn't that expensive ($100 dewalt pack off ebay). What options on escs are there though on 10s. To be able to run something like this in a car would be sweet https://www.unitedhobbies.com/UNITED...idProduct=4691. The voltage and amp specs would work but I doubt anything else would.

Edit: I just found a thread on this esc on here and you have tried this esc metalman. How did it go. Would it work on 6s lipo in the savage or would you recommend the 10s1p a123 instead.

[MetalMan]

I haven't used anything between 5s2p A123 and 10s A123, so I can't really recommend a setup. I also haven't bashed with HV yet.

With the Sentilon ESC, it's set up in my high speed MT2. It works fine for that setup, but I don't have any experience with it in any other situation.

The CC Phoenix HV series of airplane ESCs work pretty well, provided you have mechanical brakes and a PiStix adapter.

[MetalMan]

After much time sitting from the debilitating crash several months ago (as noted in post #4), this truck lives yet again! For a Savage that crash meant death - with the front right tire stuffed under the tire of a parked car, the following damage was done:
-sheared the front right axle
-bent the front right shock shafts
-broke the lower front right a-arm
-broke a left rear steering turnbuckle rod end
-broke the left rear upright

When stock parts break, it's often time to upgrade! First up were the shocks: I bought some used LST shocks off a fellow forum member, cleaned them, rebuilt them, filled them with 35wt. oil, and stuck silver springs on them with about 1/2" of preload spacers on each shock. Then I made some custom lower mounting point spacer/brace pieces that provide ample clearance from the upper arm and should keep the shock mounting very sturdy. At the top of the shocks I just used the standard LST shock bushings.

HPI CVDs replaced the front and rear driveshafts, since I got them for maybe $15 TOTAL (gotta love employee + Red Tag discounts!). When I built the CVDs I also added Hellfire axles so I could use Hellfire 17mm hex hubs.

From my boss I bought a number of aluminum Golden Horizons parts for really cheap, including front and rear shock towers, chassis braces, and the rest I haven't/won't be putting on the truck.

I also threw on a generic New Era wing mount kit I had laying around from another project, along with a Hellfire wing.

With the Savage back together, I loaded it up with only a single 5s2p A123 saddle pack (normally I run two of them for 10s2p), reprogrammed the HV-110 for a 10.6v cutoff, put the receiver in, and fired it up. Amazing! I thought for sure there would be a lot of cogging, considering that the gearing is quite tall (20t pinion, 46t spur, and stock 43/13 diffs) and the top motor RPM is below 17,000 RPM with the 1200 kv KB-45 10XL. But the starts are quite smooth, and the HV-110 allows very low motor RPM.

This truck is set up pretty well right now, with the oil/spring combination in/on the shocks, but I still feel like it would benefit quite a bit from sway bars for street running. Otherwise, WOW! Top speed is an estimated 37mph and acceleration is ballistic. Wheelies only occur on inclined surfaces thanks to the center diff. Unfrotunately the temps weren't quite so pleasing - after maybe 6 mins of pretty heavy street bashing the motor was up to 170 deg, HV-110 at ~140 deg, and the A123s were at about 100 deg. I can tell the motor is pulling a lot of current, but I can't do anything about that for now since the motor will hit the center diff outdrive with anything much less than the 20t pinion on it.

Now, if you have managed to read this whole post, you will be rewarded later!

[BrianG]

How about some sort of "idler" gear between the pinion and spur? Might help solve motor fitment issues without having to gear so tall. Don't know if it's feasible...

[jhautz]

I need to see a picture of this setp... I am trying to figure out why the motor would hit the outdrive with less that 46/20...

I have seen 46/12 run on buggies and truggies without hitting the dif outdrive. Why is this different?

[lincpimp]

He is using a 45mm diameter motor. A 46t spur is 48mm in diameter, and the 20t pinion may well be the same size as the outdrive.