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Old 05-27-2011, 11:48 AM   #31
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Originally Posted by johnny t View Post
Race cars are straight cut.

WRONG

http://www.wintersperformance.com/Wi...%20Catalog.pdf

Dirt Latemodel and Sprint car rear ends have spiral cut gears too...
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Old 05-27-2011, 03:10 PM   #32
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We keep talking whether its a technology even beneficial to an RC car. I would say no, helical gears only slow our cars down. MP9s and 8ights proved that to me.
I don't see what you mean by this since both those cars from the start have been straight cut gears.
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Old 05-27-2011, 03:12 PM   #33
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We keep talking whether its a technology even beneficial to an RC car. I would say no, helical gears only slow our cars down. MP9s and 8ights proved that to me.


man the only way you can tell if your buggy or truggy is slower using helical cut gears if your a pro not a club racer i cant tell that much of a diffrence from using straight cut gears on my losi eights .

but i respect your opinion though.
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Old 05-27-2011, 05:13 PM   #34
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I don't see what you mean by this since both those cars from the start have been straight cut gears.
I meant from the cars I have driven with straight gears (kyosho & losi) and the cars I have driven with helical (mugen & odonnell) I noticed a significant difference in off throttle coasting. Even if on the bench I could get things to spin pretty similar. (no matching a kyosho though).
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Old 05-27-2011, 05:29 PM   #35
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We keep talking whether its a technology even beneficial to an RC car. I would say no, helical gears only slow our cars down. MP9s and 8ights proved that to me.
Unless you get a set of helical gears and put them into a Losi 8ight or a Kyosho MP9 you cannot definitivley say that these buggies are faster with straight cut gears. Ryan Maifield of Associated and Atsushi Hara of Hot Bodies are respectively national champ and former world champ and they have helical gears in their buggies and they're very fast. Hara came in second to King of Kyosho and your probably gonna tell us that's because he had straight cut gears instead of helical cut gears. Ones most likely as fast as the other who the f#@k cares they both have their benefits and they both most likely have there downfalls but where is your proof that helical gears slow a car down? Nascar, f1, sprint, dirt track and indy cars all use helical cut gears in there diffs so do rally cars as well.

How is one faster than the other?

Can you say that for sure?

Is there an automotive engineer on here that could elaborate further on this?

I just want to know where your getting your information from?

I'm not a fast driver but I run similar times with the same engine from my Losi 8ight t to my D8T but I can definitely say that I haven't needed to shim or make sure the gears in my D8T are running smoothly like I had to with my
8ight t.

Just my rant for now ..................................
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Old 05-27-2011, 06:49 PM   #36
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cody king beat them all with cheaper to produce straight cut gears. so I guess thats my point.

I run a mbx6 with spiral ring and pinion. so I the advantages of straight cut are lost on me as well. mbx5 gears were straight, and is always something I meant to try in my mbx6. but like you said any meaningful affect in lap times would be minimal. but there would be a difference. at least my center driveshafts would not loosen from the repeated thrust loads on the pinion from a helical.
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Old 05-27-2011, 07:04 PM   #37
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cody king beat them all with cheaper to produce straight cut gears. so I guess thats my point.

I run a mbx6 with spiral ring and pinion. so I the advantages of straight cut are lost on me as well. mbx5 gears were straight, and is always something I meant to try in my mbx6. but like you said any meaningful affect in lap times would be minimal. but there would be a difference. at least my center driveshafts would not loosen from the repeated thrust loads on the pinion from a helical.
Well, Tebo beat them all with helical so I geuss that makes them faster. I think they both work well if setup is correct, I think that seems to be everyones point.
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Old 05-27-2011, 07:29 PM   #38
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well i have had both,straight cut and heli cut gears. the straight cut gears if not meshed properly strip easily, they still srtip over time when meshed properly also. But with the heli cut gears if they are meshed properly they are indestructable lol. Even if you have the mesh a little bit loose with heli cut gears they still seem to hold up fine. I run really thick all purpose grease in my rc8t diffs to keep the heat down preventing no wear at all. thanks
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Old 05-27-2011, 07:35 PM   #39
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well i have had both,straight cut and heli cut gears. the straight cut gears if not meshed properly strip easily, they still srtip over time when meshed properly also. But with the heli cut gears if they are meshed properly they are indestructable lol. Even if you have the mesh a little bit loose with heli cut gears they still seem to hold up fine. I run really thick all purpose grease in my rc8t diffs to keep the heat down preventing no wear at all. thanks
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i hear it all the time with the straight cut gears striping from various reasons not really the helical cut gears on my rc8t. grated i havnt ran it that much but i dont notice any wear and just using the number amount of shims it says in the manuel and thats it ! no adding extra shims or anything like that .
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Old 05-28-2011, 03:54 PM   #40
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But with the heli cut gears if they are meshed properly they are indestructable lol.
Laughable at best...by their very design, helical gears are predisposed to escape their domain. Trapping and pressure are very much required...not something in abundance with plastic R/C parts. In our full scale differentials, cast and billet housings do a fine job of holding it all together...

What exactly are you basing your statement on?
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Old 05-28-2011, 04:11 PM   #41
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Well actualy the biggest benefit you have from using helical gears compared to straight cut gears is that it drasticly reduces the soundlevel in your transmission. Which is the main reason why its used in fullsized cars.
Racecars on the other hand very often use straight cut gears which makes for a louder transmissionnoise but a smoother running drivetrain.

So, yea you would be faster with straight cut gears as there is less drag in the driveline. But on the other hand its so miniscule that you wouldnt really notice it in an RC car.
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Old 05-28-2011, 07:40 PM   #42
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Noise = sound energy. If less noise meaning less sound energy and less energy is wasted so it should be more efficient?
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Old 05-28-2011, 08:06 PM   #43
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in helical gears only a portion of the tooth is actually meshing at any given time due to the curved profile

Straight cut the whole tooth is in contact the whole time. This is why straight cut is louder. Straight cut can handle more power and torque.

In short, helical gears operate quieter than straight cut. Straight cut will 'whine' the faster they go but offer both A. More directional application of force allowing for less power loss. and B. Higher acceptable loads until failure. Basically making the transmission stronger and more efficient. However though, like noted before, car manufacturers don't use straight cut due to the imense noise the transmission will produce.

alot of cars do have straight cut in reverse only though.

i just looked all this up on the internet and have no clue if it makes a difference on our little cars, but this is the consensus that i have found.

it also explains why you will never see a spur/bell helical cut. seems like straight cut has the edge though.
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Old 05-28-2011, 08:13 PM   #44
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most gear box's have both. Matter of fact we only have 4 helical cut gears on the whole car (2 conical and 2 pinion), the rest is straight. like this here



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Old 05-28-2011, 08:14 PM   #45
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well like i said before when i ran straight cut gears and now helical cut gears i dont notice much of a diffrence the only diffrence.

the helical cut gears are quieter and smoother for sure and spins free maybe not as free as the straight gears.



but inless your a pro its hard to tell on the track.

on a full size car its diffrent likely.
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