Hellfire conversion
 

So, wanting a truggy, but being on a budget, I picked up BrainG's hellfire roller. Some of you probably remember the thread he started on it here.

I'm trying to work out a motor mount for it, and would like to use a mount in the style of RCM's where the mount replaces the rear center diff bulk. I am hoping to be able to use an existing mount, and modify the chassis as necessary to accept it.

If anyone has this type of mount, such as the Lightning Stadium, XRay, ETC, If you would be kind enough to provide me with the measurements between the mounting points, and the diameter of the hole for the diff, as well as the overall height, I would be most appreciative!



If this does not work, I plan on a piece of angle aluminum bolted to the chassis. I also have an emaxx motor plate I might utilize such as BitHed did on h is Brimstone.


Any advice is appreciated!

J.

MIght be worth a part no check but the hellfire does look very much like a lightning and I think HPI/HB are one company.

You are correct on HB/HPI. I also think the center diff bulks on the two look alike. I'm not sure if the part numbers would match up though, but it will be worth a look i'm sure.

J.

*edit*

Definitely not the same part, but the dimensions are similar. I think if I were to order the LS mount from Mike I could probably make it work. Might need the stock diff mounts for the LS as well though. It would be nice to have the measurements, it's quite difficult to determine from the pics on Tower, lol.

J. (again)

Hope BrianG doesn't mind me borrowing a pic from him for the time being, until I get my own up....


Here she is:

http://scriptasylum.com/forumpics/hellfire1_small.jpg

I see the package arrived safe and sound? :smile:

For a different conversion in the past, I just sent Mike the CD with mount and he was able to come up with a mount. Might want to email him.

BTW: the notch in the front CF piece was made to allow room for a new shock tower brace...

I have the lsp mount.The hole for the diff is 15 mm and the side the bearing goes into is 16mm. The holes in the diff mount that connects to the chassis on the front and the rear are 25mm apart and the the distance between the front and rear mount is 35mm.The height of the motor mount is 50mm. The hole on the top is 23mm in the rear mount and 24 on the front. The top mount is 34mm apart.

Sweet, thanks Blunten! I will take the measurements when I get home and see how it compares. If the center diff and bearing will fit, I'm sure I can either mod the chassis for mounting holes, or create some sort of mounting plate.

J.

Here is the motor I have ordered for this conversion,

http://www.hobbycity.com/hobbycity/s...idProduct=5422

At ~1600KV, do you think I can run this on 4s ? I have considered moving to 5s. I have a BK Warrior 9920 and Quark 125b, one or the other will be used in this. Probably the Quark.

J.

Did you read the reviews at the bottom of that page?

Smoke.
 

UH OH, he let out the smoke:gasp:, not good. Does not sound good at all:neutral:, but he did not post any specs as to how he was running it either. He may have been trying to overwork the system in his setup:whip:. The design and idea look interesting though:yes:. If you get it please let us know what happens with it:lol:.

Chris Long is our buddy Arkt1c.

The motor is too small for a truggy, and too low kv for 4s. It appears to be an align 600l knock off (at least design wise). It should be good for a buggy on 5-6s lipo. I have an align 600l that I plan to run in my recently acquired hyper 8 on 6s lipo. Should be a beast.

If you want a good inexpensive motor for the truggy, try out one of the kb 45 motors, the 8l at 2300 kv would be a beast on 4s. I have a 10l, 1800kv, in my ultra gtp and it makes tons of power on 4s and does not get hot. My MM also stays very cool too, like it is not switched on! The only issue is that the kb motors have a 6mm shaft and a 30mm bolt pattern, but I made my own motor mount so it is not a big deal to me.

Hrm. I had heard some decent things about these "hybrid" motors. I thought I would give one a shot and see what happens. I have other vehicles I can use it in. I'm sure it'll pull my little E-Savage around ok. I have an 8XL that I can use for the time being.

I don't really want to mess with drilling out a pinion to 6mm, other than that the KB motors look very nice. I'm definitely on a budget, so inexpensive is good. Eventually I'd like to have a really nice HV motor in the hellfire, but I just can't swing it right now. I puffed a maxamps last week, so now I have to go lipo shopping as well. I thought I'd pick up a 4s or 5s TrueRC 8k when I get paid this friday.

J.

I must say I would stay well clear - Just running on 4s in the basement - cruising around at low speed it got v hot v quick.

I've found a 30 to 25mm thingy to fix the mounting pattery but the 6mm shaft is a pain that I don't want to have to deal with - shame...

I've now seena a 1515 with flip diff - look v tight but hope I can use the cc 1512 copy motor...

Guess I'll stick with a feigao for this guy until I can swing something better.

True, he didn't post his specs or what he was trying to do, but I thought I'd at least warn about the possibilty of failure. Also, he said it blew within 4 minutes of running. I would think he'd have to be REALLY overworking it to blow that quickly. The specs list power as 1200w+ and the kv, but not the max rpm. 1200w should be enough to power a buggy, but the specs could be inflated. And being an outrunner hybrid, I wonder if the max rpm is lower like most other outrunners? This would really limit the usable voltage as well.

TBH, I don't see the reason for a out/inrunner hybrid. Doesn't an outrunner have more torque because of the lower kv and amp rating, rather than the high rpms that an inrunner is capable of? An inrunner can be cooled easier because the coils are physically attached to the can, which makes adding a heatsink pretty easy. To me, it seems like a hybrid actually combines the disadvantages of each motor type instead of combining the advantages.

All in all, it would probably make a good motor for a stadium truck or other 2wd vehicle that is 1/10 scale or smaller.

Not on hobbycity but I did on my thread...

http://www.rc-monster.com/forum/showthread.php?t=10618

I always knew that it was a bit small and 16.5v (5s A123) would be a bit low kv but was starting there before taxing my mm on 6S a123.

I can take some pics of what is left but the internal wiring is REALLY thin. I think in the end it cooked itself and the insulation on the woring broke down and it shorted.

Sods law I was just bringing it back for a temp check when it gave out. But after a 2 mins back and forth in basement it was too hot for finger 120+.

Thanks for the info. It's good to have some warning. I will probably give that motor a shot in my esavvy on 4s. It'll be slow, but should be something good to let other people drive rather than my 40mph e-revo. I also have a trail rig that runs 2s LiPo. With the right gearing maybe it'll make a nice trail runner / light crawler.

I can use the 8xl from my revo in the hellfire temporarily. It should be good on 4s with the BK or MM. I'd really like to go with an outrunner on 5s using the 125b, but unless I can find something in the $50-60 range for a motor, It'll probably have to wait a few weeks. Gotta buy LiPo's.


J.

then watch ebay for the 1700kv version of the align 600XL. i've heard good things about it. i was going to use it in my lsp but i scored a hacker on ebay cheap.

Yep.
 

Hey BrianG you are absolutely right. I was kind of wandering the same thing. Making a hybrid that combines the two types seems a little weird. Why would you want to in the first place? But hey for something that cheap just testing it can be interesting. With so many GOOD choices out there that are already proven to give us the power and torque that we need why bother with a cheap experimental motor. Still if you do any testing we would love to hear the results for future information when others may ask. That is what we are all about anyway, is gathering information and sharing it to help others who may not know.:lol:

Well, the first hybrid motor that I found was the align 600l, not sure if any like that were made before that motor. For heli usage the hybrid appears to be a good idea. It has more torque than an inrunner, and allows for less gear reduction, which is an issue on helis. Plus it has a higher kv than a std outrunner, needs less cells. The larger torque allows the head speed to fluctuate less for better response.

I am not so sure about this motor's usage in the car enviorment. I tested the l and xl in my emaxx and prefer an inrunner for it. I do still have the l model, and have a hyper8 buggy to try it in, on 6s lipo. So we will see how it does.

welp, I ordered 4s2p 8000mAh from TrueRC this morning. I can run it on the Revo until I get the E-Hellfire finished up. Hope to order the LSP mount from Mike this evening and figure a way to mount it in. I havn't gotten the measurements off the stock center bulks yet, but I will tonight and compare them with the measurements provided on the previous page.


J.

Looks like the LSP mount will work fine. The only thing that doesn't match up are the upper holes for the top connecting brace or whatever you'd call that. I will either need to purchase the stock center diff bulk set for LSP, or make a custom top brace that will mount to the stock hellfire one in the front, and the LSP motor mount in the back. Easy cheesy. Going to place an order for the RC-Monster LSP mount 2day :).


Brian,

What did you have in mind to secure/brace the rear end to the chassis ? I like how you've modded the rear CF piece, but I can't quite picture a sturdy way to connect that short CF piece to the chassis to provide enough strength to the stock style rear brace. Were you just going to drill the chassis for additional standoff's ?

I was thinking of a way to use some aluminum rod threaded on both ends, and bend one end at an angle to go through a hole in the shock tower, and then use a ballstud connector on the chassis for a beefy ball end connector on that side of the rod. One of those on either side of the rear driveshaft should be pretty stout. Maybe I could use some traxxas aluminum pushrod's for Revo or something. I'll have to mock up a picture if that description doesn't make sense.


J.

Edit...

Oh yeah, I was also wondering what you had pictured as an extra brace that would go through the notch you made on the front CF tray.

Have the battery on the way, and I ordered the lightning stadium mount today. I picked up the rest of what I need from tower. I should hopefully have this thing running by the weekend if everything shows up!

J.

update....
 

So, this truck just sat around in the basement until about a week ago. I got bored with busting up the tranny gears in my e-revo, and used the electronics from it to get the hellfire together. Here's what I came up with.

She's still a little rough around the edges, but running good. Although, I can only run it hard for about 15 minutes before I feel it's necessary to have a cool down period. I'm pretty well tired of feigao's. I need a better motor :). Right now I'm just biding time until the MMM starts shipping in a reliable form.


Any opinions, or general hellfire suggestions ?


J.

Wow, I guess I never saw your question. Anyway, I hadn't really thought about the back support at the time. I was going to wait for the motor and battery to see how much room I had, and then go from there. For the front, I figured a threaded rod (like maybe the pushrod from a Revo) would work, or maybe just a piece of flat CF or Al...

Nice Rig
 

Well your work seems to have paid off. That looks like a nice setup, so how does it run? Have there been other Hellfire conversions? The Hellfire was one of the first R?C vehicles that I looked at buying, but I did not want to go in the nitro direction so I went with the Maxx line. I would imagine that with the rep of the Hellfire that it handles fairly well. Good luck with that, and go for a good motor like that Neu 15151Y.

Handles great, although I need a stronger servo, or at the least a metal servo horn. The 9xl is pushing it around at good speeds. I need to get some proper wheels, as the ones I have I had been using on e-savage to widen the track. They are offset all the way out. It makes the hellfire look a bit goofy being so wide. I'm thinking on just getting the stock black dish rims and switching the tires over.

All in all, I really like it quite a lot. I have thought of a flat piece of aluminum cut on an angle to go from the rear shock tower to the chassis. Then I could use a delrin block bolted to the bottom and rear, using that to bolt to the chassis and shock tower. It's fairly firm as it is, but additional chassis bracing seems needed.

I'll definitely be looking into a MMM and Neu combo as soon as I can afford the shopping...


J.

Wow. I thought I'd perk up more interest with this one, being as there aren't many converted hellfires around here. Here's some more info....

The 9xl took a dump, so I ordered a 13t RCM pinion to run with my finned 8xl. I also switched out the BK 9920 for my quark 125b. Running with a 4s 8000mAh TrueRC. This should pack quite a punch, as long as the 8xl holds up. 13/52 @ 14.8v on the 8xl should give some nice speed.

If you noticed the wooden blocks under the revo battery tray I'm using.. that's temporary. I will replace the wood with some delrin or plastic blocks. The revo tray works pretty good for this application, so it will stay there I think.

I also want to replace the rims with the stock style black dishes. Although, the wide track is proving to be pretty fun. I can't make it traction roll for anything, even at 40mph +. It flies awesome. Very stable in the air, and easy to control. It's a lot more precise than driving the revo or savage, for sure.

I guess that's about it for now. I'm pretty much in love with it. :D.

J.

Well, this is irritating. I switched out my bk 9920 for a quark 125 due to cogging from the bk. I also had to put my 8xl in since the 9xl took a dump. I'm currently geared 13/52 and I can run for about 5 minutes before the quark thermals. the motor is getting hot as well, but not much more than expected with a feigao. The ESC however, is roasting. I'm not sure the actual temp, but hot enough to shut it down.

I can't find anything binding in the drivetrain, and I can't really gear much lower than 13/52. I think moving to a smaller spur would be a bad idea.

I also have a problem with the spur skipping when I brake. It's fine in accelleration, but when braking, it will make a nice sound like the teeth on the spur are slipping against the pinion. I find the only plastic spur that works is kyosho ? I think there's nothing bigger than 46t in that, right ?

I really like the truck, but it seems I have a few bugs to work out.


J.

Frustration
 

We can feel your frustrations, but overall your experience will leave you with an increased knowledge that can help in future projects. At least you are learning what not to do. Fuegoes do seem to have there troubles due to high temps. Personally I don't think that they are worth the hassle. Spend the money and get a motor that you know will pay off, like the 1515/1Y Neu. We rarely see issues with them and the power delivery is awsome. It sounds like you are on the right track though. Are you having fun? That is the most important thing of all.

lol, yeah, about 5 minutes worth of fun!

I had the same powertrain on my Revo conversion, and was able to run through most of the pack before needing to stop for a cooldown. I'm not quite sure why it's running so much hotter in the hellfire. Perhaps the CD is unloading too much ?

I'm sort of holding off on a new motor purchase until the Monster Max combo shows to be stable enough for me to spend money on. I'm thinking the castle neu should be pretty good for my application on 4s. I would love to spend the money on a 1515 right now, but I just can't.

This is not my first RC, or my first conversion. I have 2 revo's that I've converted, a heavily modded e-savage, and a heavily modded emaxx. that's just a few of them. I have quite a collection of tamiya's as well.

I'm just still a bit baffled by the hellfire heating things up so quickly. I was scared of burning up the 9920, so I switched it out for the 125b that was running on the emaxx. I expected the 125b to run a bit cooler than the 9920 on the same setup, but it seems that is not the case. Does anyone feel the 13/52 gearing is incorrect for this setup ? I know I need to tape the tires and such, maybe that will help. Also I'm sure heavier diff fluid in the center couldn't hurt.

Are you using an UBEC - It only has a linear bec so 4s will generate a fair amount of BEC heat.

Is the case "hot" all over - Do you need to do the internal mod? It could be worth looking at the RCM heatsink or just using an aftermarket one.

I managed to thermal mine on a buggy on a v hot day - I've geared down a bit and added a couple of 40mm fans...

30k in the middle is a good start

I am using a CC BEC. I won't risk running a quark 125 at any voltage withough one. They're hot enough as it is. I'll look into some 30w for the center. It does seem the front is unloading a bit too much for my taste. I'm sure that could result in some extra heat. It does indeed seem to be "hot all over". Not like the thermal transfer pad inside has failed or something. The case is hot enough, but it's much hotter on the PCB where the motor wires are soldered in.

J.

I find the thermal performance of the quark to be acceptable only after the "internal mod" and adding extra heatsinking (and if you insist; fans). Once that is done, it runs well. You just run the risk of messing it up. You could try adding a couple/few extra capacitors to the power input line as well.

However, the hellfire probably is kinda heavy and could benefit from the added efficiency and power of 5s. Then you can gear down to reduce the load on the system.

As far as the diff unloading goes, I used 50k in the center in my Revo (using an 8th scale style diff, not the Trx one), and it still unloaded too much.

yeah. the hellfire doesn't unload the way that my revo did with center diff, but it does unload quite a bit. I can still get a bit of a wheelie out of it though, so it seems about right to me. There's more weight up front on the hellfire than the revo, i'm sure.

I know about the quark and thermal problems, but it ran cooler than this on my very heavy emaxx. I don't know for sure. I'm going to start tearing it down tonight and see what I can come up with. I'll also probably do the thermal mod on the quark to try and get her running a bit cooler, and check all the diffs.

I wouldn't go through all the work of tearing it down. Just remove the pinion (or adjust the mesh so the pin/spur don't touch) and spin the CD to see how free it is. There is some gear drag, but the tires should keep moving a little after you spin it manually. I think it's a factor of the greater weight of the truggy vs a maxx. What speed do you have it geared for?

It's geared for about 35mph. There is a bit of drag on the CD, i noticed before putting everything together. Also there is a sort of ticking sound from the rear while free-rolling without the motor attached. Doesn't seem that the rear diff slips under power or anything though. No strange noise under acceleration at all. Also, I think my maxs is heavier than the hellfire. I'm just guessing, but with all the aluminum on the maxx it's quite a beast.

J.

Setup
 

Whats your EMaxx setup? Which version do you have? Just from your photos I would think that the Hellfire is a liter setup as well. Are you sure that you dont have a small short of some kind going on there? I am sure that you will get to the bottom of that one. Good luck with that.:lol:

the emaxx is all unlimited engineering stuff. Chassis, arms, etc. It's too heavy to do much with, but it sure looks nice, lol.

I havn't weighed them, but I'm pretty sure the hellfire is lighter. I took the electronics and motor off the hellfire last night. I think there's a bit more resistance than there should be when rolling it. Going to check the gear mesh in the front/rear diffs over the weekend.

I'm sure I'll get it worked out. I'm just bound and determined not to spend any more money on ESC's until I can get my hands on a working Monster Max. Having been through 3 quark 125's and 1 mgm16018 i'm just not going to spend that kind of money on an ESC again.


J.

Yo Brian,

You know what weight oil is in the diffs ? front/rear/center ? Just curious.....


J.