Vendetta Converting Vendetta to 6s

[LibertyMKiii]

Interesting thought I hadn't considered. Do you think it might be possible to counteract or ameliorate those forces by switching to a cylindrical roller bearing such as one of the following?
View attachment 229668View attachment 229669

Certainly looks that way. For the cost it would be worth a try.
NHBB has some documentation on it but they don't specifically call out strength for those off angular loads....

 

[vwturbowolf]

Interesting thought I hadn't considered. Do you think it might be possible to counteract or ameliorate those forces by switching to a cylindrical roller bearing such as one of the following?
View attachment 229668View attachment 229669

If you have any links to them I’ll try them out. I’ve tried a bunch of combinations but at the end of the day I break the car down after each session no matter what.

 

[Diem Turner]

If you have any links to them I’ll try them out. I’ve tried a bunch of combinations but at the end of the day I break the car down after each session no matter what.

Just search for roller bearings or cylindrical roller bearings and you should hit pay dirt.

So, there is a tradeoff. The question will become if it's worth the tradeoff. Here's a description of the difference between ball and roller bearings:

Balls make point contact with the ring raceways (ig. 2) With increasing load acting on the bearing, the contact point becomes an elliptical area The small contact area provides low rolling friction, which enables ball bearings to accommodate high speeds but also limits their load-carrying capacity.

Rollers make line contact with the ring raceways (ig. 3) With increasing load acting on the bearing, the contact line becomes somewhat rectangular in shape Because of the larger contact area and the consequently higher friction, a roller bearing can accommodate heavier loads, but lower speeds, than a same-sized ball bearing.

From the description, my gut instinct tells me no. But it could still be interesting to try out...provided they're fabricated in the required size.

 

[LibertyMKiii]

Just search for roller bearings or cylindrical roller bearings and you should hit pay dirt.

So, there is a tradeoff. The question will become if it's worth the tradeoff. Here's a description of the difference between ball and roller bearings:

Balls make point contact with the ring raceways (ig. 2) With increasing load acting on the bearing, the contact point becomes an elliptical area The small contact area provides low rolling friction, which enables ball bearings to accommodate high speeds but also limits their load-carrying capacity.

Rollers make line contact with the ring raceways (ig. 3) With increasing load acting on the bearing, the contact line becomes somewhat rectangular in shape Because of the larger contact area and the consequently higher friction, a roller bearing can accommodate heavier loads, but lower speeds, than a same-sized ball bearing.

From the description, my gut instinct tells me no. But it could still be interesting to try out...provided they're fabricated in the required size.

Certainly would need oiling each run. Would be interesting indeed

 

[SrC]

I could be wrong....... but the critcial BB's at the Rear Input Gear, we are talking about, might be better served with a Synthetic High Temp Grease perhaps? Think Mobil 1 red grease?
Has anyone tried this at 150+ mph?

 

[Diem Turner]

I could be wrong....... but the critcial BB's at the Rear Input Gear, we are talking about, might be better served with a Synthetic High Temp Grease perhaps? Think Mobil 1 red grease?
Has anyone tried this at 150+ mph?

Is that similar to Red "N" Tacky or are those two totally different products?

 

[SrC]

I don't believe R and T is a synthetic grease. Double check first.
I know Mobil 1 grease is Syn. And handles very high temps. This prevents galling at the BB races.

 

[Diem Turner]

I don't believe R and T is a synthetic grease. Double check first.
I know Mobil 1 grease is Syn. And handles very high temps. This prevents galling at the BB races.

Cheers bro. I don't have RNT, it just looked really similar visually which I know doesn't mean much which was why I asked.

 

[LibertyMKiii]

I would wonder if any lubricant can really "stay in there" under such extreme loads. Possibly a specialized surface treatment like they do for race engines.

https://www.enginebuildermag.com/2014/09/evolution-surface-treatments/

 

[Diem Turner]

I would wonder if any lubricant can really "stay in there" under such extreme loads. Possibly a specialized surface treatment like they do for race engines.

https://www.enginebuildermag.com/2014/09/evolution-surface-treatments/

I've been considering treating them with Teflon® banana peels but the harvest doesn't begin until August.

I keed, I keed. Whether or not the lube stays in there would depend largely on how much it liquifies I would think which, I assume, is what @SrC was driving at.

On a more serious note, you had suggested that you're under the impression that torque is being exerted on the input shaft/bearing at a 45° angle. Where is this angular vector coming from? The input gear meshing against the diff which is being resisted by the traction of the tires and forcing the input gear upward/downward? Just trying to understand your thought process here.

 

[LibertyMKiii]

I've been considering treating them with Teflon® banana peels but the harvest doesn't begin until August.

I keed, I keed. Whether or not the lube stays in there would depend largely on how much it liquifies I would think which, I assume, is what @SrC was driving at.

On a more serious note, you had suggested that you're under the impression that torque is being exerted on the input shaft/bearing at a 45° angle. Where is this angular vector coming from? The input gear meshing against the diff which is being resisted by the traction of the tires and forcing the input gear upward/downward? Just trying to understand your thought process here.

Just my brain mostly imagining how it fails. This is why I'd love to see how they break to understand they why/how.

I would imagine there is some scientific document/college paper out there, but I don't have the mental energy to search for it
The pinion gear is wanting to travel up the ring gear, and is held square via the input shaft/gear bearing. I imagine the end travel/load is right in the middle at 45deg.

 

[K-BASH]

Setup with the right system an the 1/10 can be ridiculously fast on 4s..my 4s 1/10 is 1 of the fastest cars I've ever had......it'll smoke any stock rc out there.....6s,8s don't matter...
Mmx8s
Tp4050-3800kv
28/36 with grps.
Have run 106mph on 3s in 1200ft with it

 

[SrC]

Just search for roller bearings or cylindrical roller bearings and you should hit pay dirt.

So, there is a tradeoff. The question will become if it's worth the tradeoff. Here's a description of the difference between ball and roller bearings:

Balls make point contact with the ring raceways (ig. 2) With increasing load acting on the bearing, the contact point becomes an elliptical area The small contact area provides low rolling friction, which enables ball bearings to accommodate high speeds but also limits their load-carrying capacity.

Rollers make line contact with the ring raceways (ig. 3) With increasing load acting on the bearing, the contact line becomes somewhat rectangular in shape Because of the larger contact area and the consequently higher friction, a roller bearing can accommodate heavier loads, but lower speeds, than a same-sized ball bearing.

From the description, my gut instinct tells me no. But it could still be interesting to try out...provided they're fabricated in the required size.

Yeah I think one limitation to Roller/Needle Bearings are the lower RPM capabilities. But I am not a pro in this area..
They work in Scale cars however.
Trial and error dictates. And some precision Bearings can really add up in price.I would also check out Boca Bearings. They offer Bearings for just about anything that uses them. Not just RC's. But commercial and Industrial Bearings and all. Call them. They will answer most any questions. Very Knowledgeable. An old Company based in Boca Raton, FL. I went there in person once when vacationing down there.
Be advised, Boca charges good money for their stuff.

 

[Diem Turner]

Just my brain mostly imagining how it fails. This is why I'd love to see how they break to understand they why/how.

I would imagine there is some scientific document/college paper out there, but I don't have the mental energy to search for it
The pinion gear is wanting to travel up the ring gear, and is held square via the input shaft/gear bearing. I imagine the end travel/load is right in the middle at 45deg.

View attachment 229783

Ok, then I was understanding you correctly. What your saying makes sense to my layman's understanding of physics

Setup with the right system an the 1/10 can be ridiculously fast on 4s..my 4s 1/10 is 1 of the fastest cars I've ever had......it'll smoke any stock rc out there.....6s,8s don't matter...
Mmx8s
Tp4050-3800kv
28/36 with grps.
Have run 106mph on 3s in 1200ft with it

Indeed. The fastest 3S car is a 1/10 scale Tamiya TRF416X @158mph. There's a lot of great things about 1/10 scale, not the least of which is probably the greatest variety of every conceivable component and accessory you can imagine. Just look at the panoply of available bodies and wheels, it's truly insane. I wish there were those kinds of options available for 1/8 or 1/7 scale.

Yeah I think one limitation to Roller/Needle Bearings are the lower RPM capabilities. But I am not a pro in this area..
They work in Scale cars however.
Trial and error dictates. And some precision Bearings can really add up in price.I would also check out Boca Bearings. They offer Bearings for just about anything that uses them. Not just RC's. But commercial and Industrial Bearings and all. Call them. They will answer most any questions. Very Knowledgeable. An old Company based in Boca Raton, FL. I went there in person once when vacationing down there.

Yeah, I was thinking the same and yes, the many different kinds of bearings and their uses is a science unto itself and precision bearings can achieve truly astronomical prices. It's possible that there isn't an economical solution to this problem and that swapping out bearings every two runs is the cheapest way to address this issue. I'm not saying it's not something worth exploring, but I suspect that smarter minds than my own have probably already spent a fair amount of time pondering solutions. Perhaps I'll delve more deeply into the topic once I start dipping into the 150mph+ stratosphere where this particular problem begins rearing its ugly head.

 

[SrC]

1/10 scale is most mainstream scale to this day. A mature scale. Was always within reach of most wallets. A scale that became dominant back in the '80's
1/8 scale only became popular in the past 10-15 years IMHO. Because Price became within reason. Outsourcing to slave labor unfortunately in many cases.

 

[LibertyMKiii]

Indeed. The fastest 3S car is a 1/10 scale Tamiya TRF416X @158mph. There's a lot of great things about 1/10 scale, not the least of which is probably the greatest variety of every conceivable component and accessory you can imagine. Just look at the panoply of available bodies and wheels, it's truly insane. I wish there were those kinds of options available for 1/8 or 1/7 scale.

My goal with the 200+ project was to take the best things of the 1/7 scale rigs from their quality 17mm hex wheels/tires, strong axles, larger hubs and bearings that can handle high power, long wheelbase for stability, high power 8s electronics, and merge that with the small aerodynamic footprint of the 1/10 scale cars and efficient belt drive setup where you don't turn the power 90 degrees like the front and rear differentials do. Yes it is copying Nic Case, but when the design is right the design is right.

It all seems to look good on paper. Hopefully, it works on the pavement too
Initial estimates say I could get near 150+ on 3s with this rig.