My BL Revo project - Page 2 - RC-Monster Forums

ttrmike · 11.18.2005, 07:03 PM

Quote:

Originally posted by nbcaznmaster
Yep! like mine! i had it fo

Cool Mr. "T" is back!:L:

BrianG · 12:47 AM

A few more questions:

Question 1
I was looking at the G-Maxx single speed tranny product (http://www.rc-monster.com/proddetail...R-AL-WS&cat=47) and it looks like it removes the rear shell half. Does the removal of four mounting screw points compromise the mounting strength of the tranny itself? I'm concerned that the weight of the BL motor and ESC (mounted to the other "Mickey-Mouse ear") when landing from a jump would be too much for just one half (4 screws) of the normal tranny mounts and break something.

Question 2
Dafni, in a previous post, you said:

Quote:

The slipper of choice would be the Strobe adapter with an Ofna spur: (Mod1 gear, nice and strong).

Are these the items you mean?

Ofna Spur: http://www.rc-monster.com/proddetail.php?prod=ofn30110
Mod1 gear: http://www.rc-monster.com/gears.php (9th item down)
Strobe adapter: http://www.rc-monster.com/proddetail...od=Slipper-Kit

Question 3
Last question. The BK Warrior 9920 has a built-in BEC. Does anyone know if it is a linear regulator or switching DC-DC type? The heatsink on that controller looks a bit small and linear BEC regulators create too much heat. Using 12 cells, the 6v regulator power dissipation at 3 amps draw would be about 25 watts! That little heatsink on the controller would barely be enough just for the BEC, let alone the ESC if it was a linear regulator. At any rate, I'll probably upgrade the heatsink on the ESC anyway so I won't need a fan. Hepefully it isn't thermal epoxied on.

squeeforever · 02:08 AM

well i think the heat sinks are fairly easy to remove but i wouldnt recommend it. with a fan it would be fine. also, if your worried about the bec on the controller mike has a ubec in the store for $35. as for the g-maxx single speed conversion, i wouldnt even worry about it. if you are really concerned about it though you can also get the flm cnc'd tranny case. the half is only $40 i think. and yes, those are the items daf ment.

-corey

BrianG · 11.20.2005, 03:32 AM

The only reason to replace the heatsink was to be able to do without a fan altogether. Adding a fan just adds to the wire count, weight, and one more thing to break.

I'm not really worried about the BEC, I was just curious. THe more I think about it, the more I'm sure it has to be a switching. After all, why would a company go through the trouble of making all the PWM circuits, just to use a linear BEC regulator? I was just hoping for a confirmation that's all.

I think I will get the CNC's case - that should appease my worries. :)

When Daf told me what I'd need, I had a bit of trouble deciphering it. I mean, the lingo is probably old hat to the experts, but I'm just starting out with this electric stuff. At least I tried to find the answers on my own, I just didn't want to buy stuff I won't/can't use.

Thanks for the answers...I can go to sleep now. :)

Dafni · 11.20.2005, 04:00 AM

Still awake? :)

Probably it wasn't just the electro lingo, but also my harsh dialect;)

The items you mentioned (slipper) are correct, but for a Feigao motor, you would need the 5mm bore pinions.

The loss of the 4 mounting holes if you go GMaxx single speed is also a concern to me. If you want, you can ask mike if he can get you just the coupler. Then you could keep both halfes, but you would need some kind of spacer for the output shaft.

I don't know exactly about the BEC. Most of us disable it anyway, and use Koolflights UBEC. I would advise you to get one as well.

For the other boys: If Brian is only looking for 25mph-ish, how about a 9XL on 12 cells?? Should give nice runtimes.

coolhandcountry · 11.20.2005, 09:17 AM

25 mph is doible with 9xl on 12 cells gp3300 is about 15 min worth of run time. I don't think the batts was the best though.

Gustav · 10:27 AM

Quote:

Originally posted by Dafni
The loss of the 4 mounting holes if you go GMaxx single speed is also a concern to me. If you want, you can ask mike if he can get you just the coupler. Then you could keep both halfes, but you would need some kind of spacer for the output shaft.

This is a great idea IMO.The FLM half case would likely stand up well to the leverage of the bigger motors but i'd like the extra security.

I was wondering whether to make a rear motor holder for XL motor or whether the optional e-maxx motor plate is strong enough.It's 4mm thick.Has anyone ever bent one of these?

Edit;also thought about maybe using the unused side of the motor plate to triangulate it with an alloy brace.

RC-Monster Mike · 11.20.2005, 11:38 AM

I haven't had any troubles with the 4 screw mounting holes on my truck - I use the g-maxx motor mount, though. I only used 4 screws when I had the full tranny case as well, though. The coupler is available seperately if you want the extra security, as dafni pointed out(I did this as well, when I first got the single speed-I installed it at the track and didn't have my dremel to modify the top shaft so I only installed the coupler with some extra bearings as a spacer into the full tranny case).

Gustav - The 4mm motor plate is most likely plenty strong, but the longer motor could always stand some rear support IMO. Two 3mm screws , each with 3-5 threads are holding the entire motor in some harsh conditions. I have never had a failure in this area, but it always made me think that more support at the rear of the motor would be best.

MetalMan · 11.20.2005, 11:53 AM

Quote:

Originally posted by BrianG
Question 3
Last question. The BK Warrior 9920 has a built-in BEC. Does anyone know if it is a linear regulator or switching DC-DC type? The heatsink on that controller looks a bit small and linear BEC regulators create too much heat. Using 12 cells, the 6v regulator power dissipation at 3 amps draw would be about 25 watts! That little heatsink on the controller would barely be enough just for the BEC, let alone the ESC if it was a linear regulator. At any rate, I'll probably upgrade the heatsink on the ESC anyway so I won't need a fan. Hepefully it isn't thermal epoxied on.

I am almost positive it is a linear regulator. If it were switching, then you would be able to use it for higher cell counts (BK says 12 cells max with BEC). Also, the regulator is on the underside of the controller, and it doesn't contact a heatsink.

BrianG · 04:36 PM

All,

Thanks for the responses.

Looks like I'll be getting the full CNC'd metal tranny case and devising some sort of lightweight spacer where needed.

As for the rear motor mount; I too think a rear motor brace would be nice because the XLs are kinda long. I'm sure I can come up with some sort of bracket. Does anyone know the length measurements of L and XL motors? Judging from diufferent pics, it looks like the XL is about 1/2" to 3/4" longer than the tranny case. I won't be getting the motor for a little while yet, but I can at least start on the bracket.

Judging by what others are running and such, I think I've decided on the 9XL or 8XL motor. Leaning more towards the 9XL just for longer runtimes despite the slower speed.

MetalMan,
I'm not so sure is isn't switching. The fact that there is no heatsink on the regulator circuit almost requires it be switching - there is no way such a small device could dissipate around 54w without a heatsink: worst case device dissipation @20 cells, @ 3amps = (24v - 6v) * 3amps. The heatsink for the entire device would almost be too small just for that! Anyway, I might just use a discrete BEC like Dafni suggested. It would just be nice to have the circuit as simple as possible - I'm only using one servo after all (Hitec HS-5945MB for steering).

I did a little more work this morning:

I added a receiver box which is just a RadioShack project box (item# 270-1801) cut lengthwise because it was too wide. I then glued a new backing. The top is held down with screws, I just didn't feel like putting them in. There should be enough roo for a BEC and maybe an on/off switch.

Also, I made a motor controller mount Dafni-style (once again). It is a bit thin, but seems sturdy enough. I might re-do it using 1/16" aluminum. I even found a spare grommet laying around for that finishing touch. :)

Pics:

Dafni · 11.20.2005, 05:31 PM

Looks good! I think the plastic tranny case looks good on your truck.

I look forward to see your motor brace, got something in the works myself. For my new Lehner 1950.

L motors are 60mm and XLs are 74mm long.

BrianG · 11.20.2005, 06:11 PM

I suppose there is no black CNC tranny case? I guess I'll see how solid the plastic one is before I go out and get the CNC one.

I should've asked this last time, but do you happen to know how much each weighs (approximately)? I want to get the truck as balanced weight-wise as possible. I've even added extra mounting holes in the battery tray so I can move them back a bit in case it is too font heavy.

Thanks in advance. Now I can start fabricating a motor bracket!

nbcaznmaster · 11.20.2005, 07:07 PM

is that a receiver box on teh right? Howd u get that?

BrianG · 11.20.2005, 07:13 PM

Quote:

Originally posted by nbcaznmaster
is that a receiver box on teh right? Howd u get that?

Like I said in the post, I picked up a RadioShack project box (3"x2"x1"), cut it lengthwise on a hand Mitre-box because it was too wide, and shoe-goo'd a piece of plastic to the opening. The cover still comes off. I then mounted it using the servo guard screws. Also, I took my dremel with a sanding wheel and sanded a half moon hole at the bottom rear (where the battery is in the pic above) for the wires to enter.

squeeforever · 08:11 PM

why is the tranny case empty?

-corey