Mojave "Superlite" Mojave [Build Thread]

[obessedwithrc]

@Dan B. - that's a great observation. I do have the PM635 on a few of my rigs. To be honest, I'm not all that sure about how much torque these servos actually need to push. I do like the speed of the PM servos, regardless of torque. I did break a 635 on my Typhon. No idea why it broke—I have yet to investigate or send it to John. Servo endpoints were set and I actually ran it on a small servo battery PM sells.

 

[calebgilmore]

@calebgilmore — I bought a slider/ roller off eBay (the body came with it). I could have bought an RTR and kept the electronics, but I already have plenty of spares on hand, so I decided to get the roller. I also have tires, receivers, etc.

Let me know what aluminum parts you want!

- Gregg

Was it an exb slider or rtr version. I wouldn't mind some of the exb towers and braces extra

 

[obessedwithrc]

Ah, it was the rtr version. Can you still get the EXB slider version? Side note: I have a Mojave EXB and plan to replace the towers and braces... I'll let you know when I start that project. Maybe I'll do both Mojave projects at the same time!

 

[calebgilmore]

Ah, it was the rtr version. Can you still get the EXB slider version? Side note: I have a Mojave EXB and plan to replace the towers and braces... I'll let you know when I start that project. Maybe I'll do both Mojave projects at the same time!

Not new but people might have one for sale used or one on ebay or something so i wasn't sure. I bought a few used ones off people a while back but have one still rtr with aluminum center braces and hinge pin blocks but i'd like to upgrade the towers eventually.

 

[Bustedaw11]

especially since I ordered aluminum screws from China and they will take 30-45 days to get.

Next time you need aluminum fasteners give these guys a try. Great pricing and super fast shipping if in US. Where I get all mine!

https://www.fastener-express.com/aluminum-fasteners-nuts-washers.aspx

 

[obessedwithrc]

Update: the rest of the parts I need are ordered. It was a long day sorting through every detail in the Mojave schematic. Lots of opportunities for weight savings! Tonight I weighed the roller and the body! This what we're starting with (below):

Roller (no electronics & no tires): 7.06 lbs​

Body (completely stock): 1.79 lbs (1lbs 12oz)​

Thanks for the tip, @Bustedaw11.

 

[obessedwithrc]

Mojave "Superlite" Build — Update #1​

Mission brief: lighten the body
Mission summary:

• Most of the hardware I ordered came in
  • Titanium screws (m3/m4 various sizes) (still waiting on M2.5)
  • Aluminum screws (m3/m4 various sizes)
  • Aluminum washers (m3/m4)
  • Aluminum locknuts (m3 both standard and flanged)
  • Aluminum nuts (m4)
• In my last update, I weighed the body, coming in at:
  • 813.1 grams (OR)
  • 1 lb and 12.6813 oz
• Removed all the screws from the body and weighed them
  • Weight: 22.59 grams
• Selected and weighed the replacement screws (a mix of Ti and Al)
  • Weight: 6.71 grams
  • 70.3% weight reduction
• Removed plastic interior from the body
  • Weight: 161.34 grams
• Weighed body again with changes made
  • Weight 560.8 grams OR
  • 1 lb and 3.7816 oz
  • 31% weight reduction

Mission conclusion:

• Was able to get some weight off! We'll see how the aluminum screws hold up. I was surprised how cheap aluminum screws were on AliExpress and how quickly they came in the mail. I have no idea what kind of quality they are, however, I did order T6 7075 Al screws from McMaster (which of course, are also made in China, along with everything else). If the ones I ordered on AliExpress fail, I'll replace them with the higher-quality screws I got from McMaster. I did not use the higher-quality screws to begin with because they only came in cap head and would weigh more than button or flat head. Yes, the weight difference would be nominal, but I am going for the gold here. Trying to build the lightest Mojave on record and I will make no compromises. Haha. That's all for this update. - Gregg aka "triple G" aka "3G network"

Plastic interior removed

 

[fish]

Mojave "Superlite" Build — Update #1​

Mission brief: lighten the body
Mission summary:

• Most of the hardware I ordered came in
  • Titanium screws (m3/m4 various sizes) (still waiting on M2.5)
  • Aluminum screws (m3/m4 various sizes)
  • Aluminum washers (m3/m4)
  • Aluminum locknuts (m3 both standard and flanged)
  • Aluminum nuts (m4)
• In my last update, I weighed the body, coming in at:
  • 813.1 grams (OR)
  • 1 lb and 12.6813 oz
• Removed all the screws from the body and weighed them
  • Weight: 22.59 grams
• Selected and weighed the replacement screws (a mix of Ti and Al)
  • Weight: 6.71 grams
  • 70.3% weight reduction
• Removed plastic interior from the body
  • Weight: 161.34 grams
• Weighed body again with changes made
  • Weight 560.8 grams OR
  • 1 lb and 3.7816 oz
  • 31% weight reduction

Mission conclusion:

• Was able to get some weight off! We'll see how the aluminum screws hold up. I was surprised how cheap aluminum screws were on AliExpress and how quickly they came in the mail. I have no idea what kind of quality they are, however, I did order T6 7075 Al screws from McMaster (which of course, are also made in China, along with everything else). If the ones I ordered on AliExpress fail, I'll replace them with the higher-quality screws I got from McMaster. I did not use the higher-quality screws to begin with because they only came in cap head and would weigh more than button or flat head. Yes, the weight difference would be nominal, but I am going for the gold here. Trying to build the lightest Mojave on record and I will make no compromises. Haha. That's all for this update. - Gregg aka "triple G" aka "3G network"

View attachment 308453


View attachment 308455

Plastic interior removed

View attachment 308457

View attachment 308459

View attachment 308458

Damn, that body originally weighs almost as much as my 8000mAh 6S Lipo battery! Thats crazy.

The aluminum screws are quite a bit heavier than steel I see but im not so sure id trust aluminum after seeing the abuse they take.
Maybe use them selectively.

Ive been buying these stainless steel screw sets from China. Haven't stripped one yet! Can't say that about the Arrma screws.
https://www.ebay.com/itm/184798080420

 

[obessedwithrc]

@fish - I will mostly use Ti screws on the main build. Since the body roll cage is plastic, I believe the roll cage would be more likely to break than an aluminum screw. I could be wrong, but we'll see! haha. Those screws from China may be cheap, but they likely are not as strong as the stock Arrma screws. Tekno makes really good screws (the best I've ever seen—the threads are so neatly cut and "grabby").

McMaster has a really great chart that shows the tensile strength of different classes of screws.

 

[Mr9Mojave]

Mojave "Superlite" Build — Update #1​

Mission brief: lighten the body
Mission summary:

• Most of the hardware I ordered came in
  • Titanium screws (m3/m4 various sizes) (still waiting on M2.5)
  • Aluminum screws (m3/m4 various sizes)
  • Aluminum washers (m3/m4)
  • Aluminum locknuts (m3 both standard and flanged)
  • Aluminum nuts (m4)
• In my last update, I weighed the body, coming in at:
  • 813.1 grams (OR)
  • 1 lb and 12.6813 oz
• Removed all the screws from the body and weighed them
  • Weight: 22.59 grams
• Selected and weighed the replacement screws (a mix of Ti and Al)
  • Weight: 6.71 grams
  • 70.3% weight reduction
• Removed plastic interior from the body
  • Weight: 161.34 grams
• Weighed body again with changes made
  • Weight 560.8 grams OR
  • 1 lb and 3.7816 oz
  • 31% weight reduction

Mission conclusion:

• Was able to get some weight off! We'll see how the aluminum screws hold up. I was surprised how cheap aluminum screws were on AliExpress and how quickly they came in the mail. I have no idea what kind of quality they are, however, I did order T6 7075 Al screws from McMaster (which of course, are also made in China, along with everything else). If the ones I ordered on AliExpress fail, I'll replace them with the higher-quality screws I got from McMaster. I did not use the higher-quality screws to begin with because they only came in cap head and would weigh more than button or flat head. Yes, the weight difference would be nominal, but I am going for the gold here. Trying to build the lightest Mojave on record and I will make no compromises. Haha. That's all for this update. - Gregg aka "triple G" aka "3G network"

View attachment 308453


View attachment 308455

Plastic interior removed

View attachment 308457

View attachment 308459

View attachment 308458

Would be interesting to see this graph with it fully loaded.

 

[Garcbomber]

whoops accidentally keep bumping your feather off the SC track around corners , good luck

 

[obessedwithrc]

whoops accidentally keep bumping your feather off the SC track around corners , good luck

Haha. That might just happen! Just wait until you see what else is coming. I'll be saving weight down to the grub screws! It probably won't be more than 20% Arrma by the time I'm done with it.

- Gregg

 

[Dan B.]

@Dan B. - that's a great observation. I do have the PM635 on a few of my rigs. To be honest, I'm not all that sure about how much torque these servos actually need to push. I do like the speed of the PM servos, regardless of torque. I did break a 635 on my Typhon. No idea why it broke—I have yet to investigate or send it to John. Servo endpoints were set and I actually ran it on a small servo battery PM sells.

That’s uncommon. I really like the PM 630’s as well, but the 635 jumps up in gear train quality according to John, and of course almost all the specs are better. Every time I order a 630, he’s like “you sure you don’t want a 635?”

@fish - I will mostly use Ti screws on the main build. Since the body roll cage is plastic, I believe the roll cage would be more likely to break than an aluminum screw. I could be wrong, but we'll see! haha. Those screws from China may be cheap, but they likely are not as strong as the stock Arrma screws. Tekno makes really good screws (the best I've ever seen—the threads are so neatly cut and "grabby").

McMaster has a really great chart that shows the tensile strength of different classes of screws.

View attachment 308499

View attachment 308500

View attachment 308501

McMaster is a great resource, but I’ve never seen this chart before. Super useful info, thanks!

 

[obessedwithrc]

Mojave "Superlite" Build — Update #2​

Mission brief: Steering (part 1 of 2)

Lighten steering rack

• Aluminum 7075 locknuts (1UP Racing)
• Titanium screws (misc. brands)
• Carbon fiber Ackerman bar (Scorched)
• Basherqueen Adjustable Lockable Servo Saver Kit (eBay)
• Tekno aluminum steering posts* (TKR9102A)
• Tekno steering link rod ends (TKR5056)
• Tekno servo link aluminum balls (TKR5058A)
• T-Works titanium 3x10 set screw (for steering link)
• Ceramic bearings

Build notes:
*The Tekno aluminum steering posts were exactly the same length as the stock posts; however, the flange at the bottom of the posts is higher than stock, so I had to add spacers to the front bulkheads and made some other modifications to make them work (pics to follow).

Flanged bearing kit from Scorched

Stock steel steering posts

Tekno aluminum steering posts

 

[obessedwithrc]

Mojave "Superlite" Build — Update #3​

Mission brief: mounting electronics

Battery box/ tray​

• I was going to try to use a carbon fiber tray from Xtreme Racing, but even though I was going to use aluminum standoffs and titanium screws, the weight of the tray with hardware was nearly identical in weight to the stock battery tray
• I decided to use the stock battery tray with titanium screws

Xtreme Racing battery tray

Xtreme Racing battery tray with hardware, plastic holders, and straps

Stock tray with Ti screws & CF pins

The plastic piece that locks down the top/ front of the battery (notice the two steel pins)

With steel pins removed and replaced with 2.5 mil carbon fiber rod (kinda hard to see in this pic because the pins are black)

ESC plate/ mount​

• I looked at using carbon fiber for the plate to reduce weight, but after the hardware was included, the plates were nearly the same weight

Stock plate with Ti screws

Xtreme Racing ESC plate

Servo Mount​

• I compared the stock servo mount to a CF/ aluminum servo mount from Schorced

Stock plastic servo mount with stock hardware

CF/ aluminum servo mount with Ti and aluminum hardware

Overall, not much weight savings in the electronics mounting category...

 

[obessedwithrc]

Mojave "Superlite" Build — Update #5​

Mission brief: driveline components

Driveline cups​

• Not much luck on weight savings here...
• Stock diff cups were not true and the driveshaft wobbled
• I looked at using Tekno cups, but they were a tad too long compared to stock
• I looked at M2C, which was heavier than stock
• Scorched is slightly heavier, but I used them because I know they will run true
• Using Schorched titanium driveshafts (not pictured) - not sure if they are lighter, but they are freakin' awesome (I forgot to weigh them)

Stock diff cup

Tekno diff cup

M2C diff cup

Scorched Parts diff cup

Diffs​

• Not much luck on weight savings here, either, unfortunately
• Hot racing spur is lighter
• I was also able to remove the weight of the m4 grub screw by replacing it with plastic (gluing it in) (part is from McMaster)
• Other: Used Ti screws
• Other: Was planning to use a Ti pin, but I bought 2.5mm titanium stock instead of 2.25mm stock (took 30 days to get here from China and I don't want to wait another month for a 2.25 mil stock bar)

Stock 50T spur gear

Hot Racing 50T Spur gear

M4 plastic grub screw

Titanium pins (2.5mm) - meant to get 2.25 for diff pins, but I will use Ti for the wheel nuts