Correct MT Pinion

[3D Dave]

Hey guys,

I'm about to order my JGF450TH motor. What brand pinion should I buy? It appears that my stock 13T will put headspeed a little too high for me right now. I'm at 2450 with the stock motor and would like to stay around that (or around 2500-2600) for now. I think I'll get a 11 and 12T but it looks like Thunder Tiger does not offer those sizes.

I thought I'd read that T-Rex (Align) pinions do not work well and end up eating the teeth off the stock MT main gear so I'd like to avoid those.

Can you tell me which brand is compatible? If what you recommend is NOT available at Helidirect, direct me to your favorite USA dealer.

Thanks!

Dave D.

[mkoutnik]

Check out the Rhino Gear pinions at HeliDirect...

https://www.helidirect.com/advanced_search_result.php?keywords=pinion&osCsid=9b7512a45b092f40889b8245c6433305

[dviry]

I personally went for the 12T from RevCo, but I haven't installed it yet :roll:

https://www.readyheli.com/ProductDetails.asp?ProductCode=HO-1012

[john_3330]

Jus stick with the 13T.. Headspeed wouldn't be too high.. Used it before and was awesome!

[helicraze]

Use the 13T.

TT sells a 10/13/15T pinion for the mini T

[john_3330]

TT also has 12T and 14T..

[3D Dave]

Thanks guys.

Can you give me part numbers and vendor names that stock TT 12T pinion?

Otherwise I'm probably going with Rhino or RevCo.

Just for the heck of it though I might just try the 13. The thing is, I'm not as afraid of the higher headspeed as I am the reduced flight time. I was advised, however to not go over 2700RPM with my stock plastic head, grips, and wood blades.

I'm getting 9-10 minutes now on 2200 Revolectrix packs.


Dave

[helicraze]

I'd only be worried about the wood rotors! Get some carbons, they are cheap, it will fly better and also that will give you an extra 1-2 min flight time anyway from reduced drag, it has been proven!

[3D Dave]

Thanks helicraze. I've been flying the Align Pro Woods with great results. I think I will try carbons soon but my main objective is to get a new motor (with the same power characteristics as the TT stock) that runs really cool.

There are several guys on another list telling me I should get the JGF500TH motor instead of the 450TH. My headspeed is NEVER going to go to 3000+RPM and for now I don't see it going above 2600RPM so I still think the 450TH would be the better motor as it's designed to run most efficiently at that 2400-2700 range.

Would you guys agree?

Dave

[helicraze]

How many KV are the motors? Around 3700KV is perfect IMO

[Bayward]

There are several guys on another list telling me I should get the JGF500TH motor instead of the 450TH. My headspeed is NEVER going to go to 3000+RPM and for now I don't see it going above 2600RPM so I still think the 450TH would be the better motor as it's designed to run most efficiently at that 2400-2700 range.

Would you guys agree?

Dave

1) Motor RPM = Motor KV X volts ( 3.7 for lipo ) X number of cells X constant ( 0.8 ).

2) Head speed = Motor RPM / Gear ratio.

3) Gear ratio = 150t ( Mini Titan main gear number of teeth ) / Motor pinion number of teeth.

First the 500th which is 3380kv. 3380 X 3.7 = 12506. 12506 X 3 cells = 37518. 37518 X 0.8 = 30014.4.
Using a 13 tooth pinion. 150 / 13 = 11.538. So, 30014.4 / 11.538 = 2601.352 RPM head speed.

13 tooth pinion = 2601.4 RPM head speed.
12 tooth pinion = 2401.2 RPM head speed.
11 tooth pinion = 2201.1 RPM head speed.

450th motor is 3000kv. Using the same formula we get:

13 tooth pinion = 2308.9 RPM head speed.
12 tooth pinion = 2131.2 RPM head speed.
11 tooth pinion = 1953.7 RPM head speed.

Stock OEM motor supplied with the Mini Titan is 3500kv. Again using the same formula:

13 tooth pinion = 2693.7 RPM head speed.
12 tooth pinion = 2486.4 RPM head speed.
11 tooth pinion = 2279.3 RPM head speed.

If you look at these numbers you will see the 500th more closely approximates the OEM motor than the 450th. That is why so many people keep telling you the 500th is a better choice. The 450th will fly the Mini titan well, but the 500th is closer to factory original.

Bob

[3D Dave]

Bob,

THANK YOU!!!!!!!

Those number comparisons are VERY helpful!!!

I have not bought the JGF motor yet as I bought and installed the AXI motor fan. It's helped quite a bit (and we've had lower than normal temps in Chicago).

Now that I've seen the comparison, I think I'll look at the JGF500TH again. One thing I forgot to mention though is the JGF developer told me the 450TH is designed to run most efficiently (and cooler) at 2400-2600RPM where as a 500TH is designed to run at 2700-3200.

I don't plan on going above 2600 with wood blades on this MT.

Dave

PS, It just occured to me that maybe the stock motor is getting too hot because I'm not running it FAST ENOUGH??? I will have to look into this further. I do know that a LOT of guys say the OEM motor gets too hot though. My headspeed was about 2000 when I was first learning to hover. Now that I'm at 2450 and doing more than hovering (plus the AXI fan) maybe it's not so bad.

[dviry]

I've read somewhere that these brushless motors run most efficiently between 95%-100% throttle. Interesting enough, now that I am running at 95% (with 12T) and doing more than just hovering I've noticed that everything seems to run cooler and longer too!

I guess hovering puts much more strain and doing some FF also helps cooling things down (outside temp here is 95-110F - gotta love Texas)... :smokin:

[BigEdge]

I've read somewhere that these brushless motors run most efficiently between 95%-100% throttle. Interesting enough, now that I am running at 95% (with 12T) and doing more than just hovering I've noticed that everything seems to run cooler and longer too!

I guess hovering puts much more strain and doing some FF also helps cooling things down (outside temp here is 95-110F - gotta love Texas)... :smokin:

+1 on that..
I run my stock MT SE at 100% throttle (with 13T)
She likes it...!