Rlaarlo AK917 carbon roller build

[Dan B.]

I finally got out the first of two AK917’s to build. Overall I’m really pleased and impressed with most of the car, but those guys need to get it together with QC on their spare parts orders. I’m using an HW Max10 G2 setup, so I ordered a variety of Rlaarlo steel pinions for 5mm shafts. One was mislabeled and was one of the smaller shaft size pinions. And every pinion I ordered came with grub screws that were too small, which is a PITA. It almost depleted my supply of grub screws, I’ll have to order more.
Started removing the motor mount to replace with their sliding, top adjustable mount.

None of the grub screws seemed to be loctited on the center shafts or drive cup. Also, if you’re building one of these, when I pulled them apart they were practically dripping with machine oil from the carrier bearings. I removed and cleaned the whole center drivetrain, put the well oiled bearings back, and loctited everything. I noticed when I got out the motor plate that one of the top threaded screw holes for the adjuster screws was machined off-center and the cut thread reliefs are peeking through the aluminum! I did check it, and it’s still very close to center and threads in securely so I’m going to use it.

I clocked the motor on the sliding mount to dry fit it. I put the pinion on it and the bore in the center of the plate is too small to allow the pinion to rotate because the goddamned grub screw rubs on the bore. The grub screw can’t be exposed more than 0.5mm when tight. Seriously? Very freaking disappointing. These are Rlaarlo pinions and motor mount, and they don’t play well with one another? I had to take a ridiculous amount of material out of the bore to clearance it. I know a lot of you guys used the Hobao mounts, and in hindsight I would have.

I used the factory servo mount and put in a $35.00 Ali sourced JX servo. It seems like a quality piece, nicely machined cases anyway. If the specs of the servo are even fairly close to stated it should be great for this tiny light car and it seems to center well, too.
For Gods sake, don’t tell John. I think this is the first car I’ve built in years without a ProModeler servo in it.

I’ll be fitting a small receiver box somewhere.
Overall I really like the car, and the quality of pretty much the whole thing is very impressive for the price. Dude, $168.00 for a nice carbon roller?!?!
Rlaarlo needs to get their own parts incompatibility issues resolved though, it was a shame to have to overcome so much dumb sh*t in the first five minutes of the build.
I‘ll update this in a day or two.

 

[Jamr]

I finally got out the first of two AK917’s to build. Overall I’m really pleased and impressed with most of the car, but those guys need to get it together with QC on their spare parts orders. I’m using an HW Max10 G2 setup, so I ordered a variety of Rlaarlo steel pinions for 5mm shafts. One was mislabeled and was one of the smaller shaft size pinions. And every pinion I ordered came with grub screws that were too small, which is a PITA. It almost depleted my supply of grub screws, I’ll have to order more.
Started removing the motor mount to replace with their sliding, top adjustable mount.
View attachment 335922
None of the grub screws seemed to be loctited on the center shafts or drive cup. Also, if you’re building one of these, when I pulled them apart they were practically dripping with machine oil from the carrier bearings. I removed and cleaned the whole center drivetrain, put the well oiled bearings back, and loctited everything. I noticed when I got out the motor plate that one of the top threaded screw holes for the adjuster screws was machined off-center and the cut thread reliefs are peeking through the aluminum! I did check it, and it’s still very close to center and threads in securely so I’m going to use it.
View attachment 335927
I clocked the motor on the sliding mount to dry fit it. I put the pinion on it and the bore in the center of the plate is too small to allow the pinion to rotate because the goddamned grub screw rubs on the bore. The grub screw can’t be exposed more than 0.5mm when tight. Seriously? Very freaking disappointing. These are Rlaarlo pinions and motor mount, and they don’t play well with one another? I had to take a ridiculous amount of material out of the bore to clearance it. I know a lot of you guys used the Hobao mounts, and in hindsight I would have.
View attachment 335930
I used the factory servo mount and put in a $35.00 Ali sourced JX servo. It seems like a quality piece, nicely machined cases anyway. If the specs of the servo are even fairly close to stated it should be great for this tiny light car and it seems to center well, too.
For Gods sake, don’t tell John. I think this is the first car I’ve built in years without a ProModeler servo in it.
View attachment 335931
View attachment 335928
I’ll be fitting a small receiver box somewhere.
Overall I really like the car, and the quality of pretty much the whole thing is very impressive for the price. Dude, $168.00 for a nice carbon roller?!?!
Rlaarlo needs to get their own parts incompatibility issues resolved though, it was a shame to have to overcome so much dumb sh*t in the first five minutes of the build.
I‘ll update this in a day or two.

View attachment 335926

That is why I bought a RTR for only 132$ more. Let them deal with the issues.
Sorry you had the problems.

 

[Dan B.]

That is why I bought a RTR for only 132$ more. Let them deal with the issues.
Sorry you had the problems.
View attachment 335932

Yeah, I pretty much only buy rolllers whenever possible so I can set them up the way I want and choose my own electronics.

 

[Xjeepguy]

Great write up man, I’ll be following this build for sure. Looks awesome!

 

[Jerold]

Welcome to the rabbit hole.

It's got the good and the bad. I would highly recommend moving to mod 1 gears. The 48p gear from Rlaarlo are sort of weak and the Mod 1 gears are smoother too.

 

[Dan B.]

Welcome to the rabbit hole.

It's got the good and the bad. I would highly recommend moving to mod 1 gears. The 48p gear from Rlaarlo are sort of weak and the Mod 1 gears are smoother too.

I think I’m going to go Mod 0.8 as there are seemingly a lot more gear combinations in 5mm and will still be a good upgrade from 48p.

 

[Jerold]

I think I’m going to go Mod 0.8 as there are seemingly a lot more gear combinations in 5mm and will still be a good upgrade from 48p.

Island Hobby has a lot more Mod 1 gears options than Amain.
https://islandhobbynut.com/

I did some calculations for the Mod 1 gear sizes in my build.
https://www.rctalk.com/forum/threads/jerolds-rlaarlo-build.138240/page-3#post-1385590

We can figure it out for 0.8 if you decide to go that route. The center to center distance is critical (~28.5-35.5mm). Also the max OD of the gears are limited to <36mm pinion and <40mm spur.

 

[Dan B.]

Island Hobby has a lot more Mod 1 gears options than Amain.
https://islandhobbynut.com/

I did some calculations for the Mod 1 gear sizes in my build.
https://www.rctalk.com/forum/threads/jerolds-rlaarlo-build.138240/page-3#post-1385590

We can figure it out for 0.8 if you decide to go that route. The center to center distance is critical (~28.5-35.5mm). Also the max OD of the gears are limited to <36mm pinion and <40mm spur.
View attachment 335968

Hmmmm, not on mine. I dry fit a 52t spur with a 45t pinion and could get good mesh with room to spare, and a lot of headroom to gear up.

 

[Jerold]

I think that might be too big, assuming you have the same mount I do?
View attachment 335976

When you change the pitch all the parameters of the gears change. So a 52T 48P gear is not the same diameter as a 52T Mod .8 gear.

The pinion is limited to the max diameter of the motor (36mm) and you will need a smidge of room for clearance. I don't recall how I measured the Spur but it was less than 40mm. The Center to Center distance was calculated using the pinion spur combination (48p) from the Rlaarlo website, then using those dimensions.

You can swap 52T->42T and 45T->36T and get near the same ratios.

Lets double check all the math before you order gears though.

 

[Dan B.]

I think that might be too big, assuming you have the same mount I do?
View attachment 335976

When you change the pitch all the parameters of the gears change. So a 52T 48P gear is not the same diameter as a 52T Mod .8 gear.

The pinion is limited to the max diameter of the motor (36mm) and you will need a smidge of room for clearance. I don't recall how I measured the Spur but it was less than 40mm. The Center to Center distance was calculated using the pinion spur combination (48p) from the Rlaarlo website, then using those dimensions.

View attachment 335977

You can swap 52T->42T and 45T->36T and get near the same ratios.
View attachment 335978

Lets double check all the math before you order gears though.

You are correct sir, that’s why I said I’ll have more gearing options with mod 8.

 

[Dan B.]

I think that might be too big, assuming you have the same mount I do?
View attachment 335976

When you change the pitch all the parameters of the gears change. So a 52T 48P gear is not the same diameter as a 52T Mod .8 gear.

The pinion is limited to the max diameter of the motor (36mm) and you will need a smidge of room for clearance. I don't recall how I measured the Spur but it was less than 40mm. The Center to Center distance was calculated using the pinion spur combination (48p) from the Rlaarlo website, then using those dimensions.

View attachment 335977

You can swap 52T->42T and 45T->36T and get near the same ratios.
View attachment 335978

Let’s double check all the math before you order gears though.

I think I have all the gears I’ll need for this chassis. I’ll be running a 52-63 spur and a 30-50 pinion with room to spare, staying with the steel 48p for now. I’ll play with the gearing and then move to mod .8 if I start having issues. I have another one after this to build, so this one is my learning curve.

 

[Gordo]

Good luck Dan, reading this stuff is very interesting, that's what I like about AF there's a lot of smart people who like to play with big boy toys.

 

[dure16]

These little things are fun to build. Sucks about the QC issues.

I designed a low-pro servo mount for the battery side that seems to work well. Let me know if you need the 3D file.

 

[Dan B.]

Got the electronics installed, minus the receiver box. Tight squeeze! (HobbyWing Max 10 G2 140amp sensored system with the 4000kv G3 sensored motor.) This thing should rip on 3s! I shortened the motor wires considerably but obviously couldn’t shorten the sensor wire so I did some creative cable routing and put a cable clamp on the chassis to keep it out of the drivetrain.
I‘m not using the Rlaarlo receiver that has the light controller built into it (with functional turn signals, tail lights, brake lights, head lights, and “backfire” exhaust lights) so I removed the exhaust tip lights and I’ll be soldering everything else together to light the tail lights and headlights. I’ll put that in an Aux slot on the receiver with a cheap light controller switch so I can switch them from the radio.
I have a very small receiver box that should arrive today, and that’s going to live on top of the center carbon brace.

 

[Dan B.]

Did some work on the Rlaarlo chassis. Mounted the receiver box and installed the RL R7FG receiver. Chopped the XT-60 plug that came on the HW ESC and soldered on an XT-90 as well as a battery telemetry lead for the receiver. That’s the smaller shielded wire you can see going into the receiver box. The thicker shielded cable you see contains the ESC and servo leads. The JXT connector protruding from the receiver box is attached to a light controller in the box on channel 3 so I can turn the lights on or off through the radio.
I still need to splice, solder, shield, and route the lighting wires and make a mount for the antenna leads. I’ve groused in the past about the limited real estate in the SWB/Typhon chassis, but going to 1/10 TC is a whole new challenge in regard to keeping things tidy. My OCD is in high gear at the moment. It seems that self medicating is the best possible solution at the moment.

 

[Dan B.]

I got all the light wires shortened up and soldered, and tucked away as unobtrusively as possible. I ended up switching them through channel 6 so I could use the most out of the way switch on the radio without reassigning stuff, and that leaves the ability to keep channel 3 for the gyro using the VR knob on the radio to adjust sensitivity.
While waiting for my “helper” to go to bed (couldn’t fire up my soldering station with a kitten crawling all over my workbench) I peeled most of the graphics from the body and “re-liveried” it to vaguely resemble a Porsche 917. I like it much better.
I powered it up for the first time, calibrated the ESC and gyro, and dialed in some radio settings. All that’s left to do is mount the antennas, check the suspension settings, and give her a rip!

Here is my helper, Nacho. It’s been a long time since we’ve had a kitten in the house. I’d forgotten… That cat is into EVERYTHING at hyper velocity. Little bastard moves a lot faster than I do. What a handful.

 

[Dan B.]

I got everything buttoned up. I removed that silly fan on the body, but left the fan cover on and drilled two 3mm holes directly beneath it on either side of the carbon fibre center brace (more on this in a moment) to friction fit the antenna tubes into. The antennae exit through the holes on the fan cover so I didn’t need to punch more holes in the body.

And BTW, those Saga battery straps are the bees knees. I’ll never buy another kind again.
In regard to drilling the two 3mm holes in the carbon fibre center brace… This is the lowest quality carbon I’ve ever seen in RC, or anywhere else for that matter. I’m sure that strictly speaking, in a technical sense it is indeed carbon fibre, but I gotta tell you, it ain’t no Scorched or BQ quality. Just drilling 3mm holes properly with a sharp bit cause delamination of the layup and a bit of separation. In my next Rlaarlo build (stay tuned, it’s going to be groovy) I’ll probably fab my own center brace and toss the carbon containing cardboard laminate brace that it came with in the trash.
That said, this was a really fun build on an extremely inexpensive roller and the results and overall impressions exceeded my expectations. This is really a nice bit of kit for the money.
I obviously didn’t take this AK917 to the level that @Jerold or @vwturbowolf did, but I think my approach of building a cool little street ripper out of it is going to be a lot of fun.
I’m calling this one done!

 

[LibertyMKiii]

Great build Dan!
Keep us posted how it runs, how fast it goes, and how the temps are. I like that motor choice for a street ripper.

Also what is the block you have all your MIP tools in? (Im thinking its just a block of foam but looks nicer than foam) I need something like that....

 

[Dan B.]

Great build Dan!
Keep us posted how it runs, how fast it goes, and how the temps are. I like that motor choice for a street ripper.

Also what is the block you have all your MIP tools in? (Im thinking its just a block of foam but looks nicer than foam) I need something like that....

Thank you very much sir. It sure ain’t close to the one you built, though!
And yup, that’s a cheap foam yoga block. Just shove your drivers in there in any orientation you choose. Works super well. Also for dremel bits, drill bits, allen keys, etc.

These are the ones I got, but I see the price increased a bit from when I bought them. I think I paid like $19.00 or something for a pair. You can probably find foam yoga blocks cheaper than these are now I’ll bet.
https://www.amazon.com/Gaiam-Essent..._grid_rp_0_1_ec_ppx_yo_dt_b_search_bia_t&th=1
They also work great for RC stands, and that’s what my rigs set on when they’re on the shelf so the tires don’t flat spot.

 

[LibertyMKiii]

Thank you very much sir. It sure ain’t close to the one you built, though!
And yup, that’s a cheap foam yoga block. Just shove your drivers in there in any orientation you choose. Works super well. Also for dremel bits, drill bits, allen keys, etc.
View attachment 341502
These are the ones I got, but I see the price increased a bit from when I bought them. I think I paid like $19.00 or something for a pair. You can probably find foam yoga blocks cheaper than these are now I’ll bet.
https://www.amazon.com/Gaiam-Essent..._grid_rp_0_1_ec_ppx_yo_dt_b_search_bia_t&th=1
They also work great for RC stands, and that’s what my rigs set on when they’re on the shelf so the tires don’t flat spot.

Awesome, thanks!
It is hard to beat something like that for fitting the tools so snug together and take up less bench top space. The only alternative would probably be to 3d print something but this wins by being simple and works so good.