How to install the 20T autorotation gear?

[ke6d]

Hi,

I am thinking about removing the old 19T autorotation gear and installing the 20T. For the brave souls who already have done this, how did you do it? Is there any gear mesh problem when the new gear (obviously a little bit larger) is installed?

Thanks,

Dan

[CompuFoil]

First, loosen the two motor pinion set screws, and remove the main gear. Now just push the shaft down from the top, out through the one way, bearings and gear. You should be able to remove the one way and install the new one the same way. I have been told that the 20T is the same diameter as the 19T, but the pitch is a bit smaller, yet still engages the main gear properly.
Eric

[istandalone]

no mesh issues whatsoever with the 20t.

[CompuFoil]

Just did it. It was a 15 minute event. Just be sure you put it in the right direction, or you will be pulling it out again.
Eric

[Happy|Harry]

Originally Posted by CompuFoil

First, loosen the two motor pinion set screws, and remove the main gear. Now just push the shaft down from the top, out through the one way, bearings and gear. You should be able to remove the one way and install the new one the same way. I have been told that the 20T is the same diameter as the 19T, but the pitch is a bit smaller, yet still engages the main gear properly.
Eric

the pitch is exactly the same at 0.8Mod but the 20T is only slightly larger than the 19T and causes no mesh problems when fitted

phil

[GatoVolador]

Two thumbs-up for the 20T oneway! I had the 19T oneway slide down on the metal sleeve and it ground-up my bottom alu bearing block (I have the CF frames). When this happens the 19T oneway will be engaging about half of the main gear and you'll either strip it or the oneway will start slipping. The 20T oneway gear is taller then the 19T oneway so even if it is riding against the bottom bearing block it is still fully-engaging the main gear -- much better design in my opinion. I think all hurri owners should get it just for that reason....

[mjdee14]

Is there a benifit to using the 20t ? What does it do to the gear ratio?

Anyone have any thoughts on this?

Update ** according to the HS calc...with my Z20 980kv and stock gears 14t pinion swithcing to the 20t oneway picks up about 100 rpm goes from 2033 to 2140 using 90% as the drag...

[Happy|Harry]

Originally Posted by mjdee14

Is there a benifit to using the 20t ? What does it do to the gear ratio?

Anyone have any thoughts on this?

Update ** according to the HS calc...with my Z20 980kv and stock gears 14t pinion swithcing to the 20t oneway picks up about 100 rpm goes from 2033 to 2140 using 90% as the drag...

the 20T oneway is more beefy and less prone to splitting like the 19T one is, i've attached my pdf of available gear ratios, the first page is with the 19T and the second page is with the 20T

phil

[GatoVolador]

Originally Posted by mjdee14

Is there a benifit to using the 20t ? What does it do to the gear ratio?

Anyone have any thoughts on this?

Update ** according to the HS calc...with my Z20 980kv and stock gears 14t pinion swithcing to the 20t oneway picks up about 100 rpm goes from 2033 to 2140 using 90% as the drag...

It's about a wash as far as gear ratios are concerned but the bigger benefit in my opinion is the gear is taller and will always be engaging the main gear regardless if it slips on the sleeve or not.

[mjdee14]

Originally Posted by Happy|Harry

the 20T oneway is more beefy and less prone to splitting like the 19T one is, i've attached my pdf of available gear ratios, the first page is with the 19T and the second page is with the 20T

phil

HH...

Thanks for the spreadsheet...it's a "Keeper" good to have all the info in one place....

Thanks again.

Looks like I'll be getting the 20 t for the beefiness..

I love the Hurri, but it's amazinghow WE find all the weak spots. Where was the R & D and beta tests?

Reminds me of my airline days.....Boeing used to test a/c doors like "thousands of times"....then 105lb flight attendant would totally destroy it !!

[ke6d]

See this thread. I uploaded a Hurricane headspeed calculator spreadsheed with almost all the gear combo calculation. You can just look up the headspeed for your gear combo. Revco gears and pinions are also included. This is assuming 100% efficiency. Multiply this value by 0.90 for 90% efficiency.

Dan

https://www.helifreak.com/showthread.php?t=59123

[Happy|Harry]

very nice spreadsheet dan :cool:, though you should have left the primary, secondary, pinion, oneway, motor Kv and voltage as user selectable values as there are lots of different options for the primary gear

i did include the revco gears in my first version of the document but after all the problems with people stripping them on high power setups i decided that mod 0.6 gears aren't suitable for my use so i removed them, i should have probably left them in for others benefit but i didn't think about that :o

phil

[ke6d]

Originally Posted by Happy|Harry

very nice spreadsheet dan :cool:, though you should have left the primary, secondary, pinion, oneway, motor Kv and voltage as user selectable values as there are lots of different options for the primary gear

i did include the revco gears in my first version of the document but after all the problems with people stripping them on high power setups i decided that mod 0.6 gears aren't suitable for my use so i removed them, i should have probably left them in for others benefit but i didn't think about that :o

phil

Hi Phil,

Thanks. I was lazy. I just copied more rows when I need more gear/motor Kv choices. It was 30 min job I thought it might be useful to someone.

Dan

[Happy|Harry]

dan it is indeed useful! though i've taken the liberty of modifying it to be as i mentioned above where you can input most of the values and get the resulting gear ratio and headspeed, with also calculations that take the drag coefficient into account. let me know what you think

phil

[edit]
i have attached the file in post no:17
[/edit]

[Borneoben]

Hi HH

Cant seem to download your Zip File

Is there a chance i can download it from somewhere else?

Ben

[mjdee14]

Originally Posted by Wazzer

Hi HH

Cant seem to download your Zip File

Is there a chance i can download it from somewhere else?

Ben

Me neither..

[Happy|Harry]

i can download it from here? i've tried to re-attach it to this post but the site wont let me saying that i have already attached it in post 14 of this thread

phil

[edit]
ok guys i've deleted it from the above post and re-attached it here, if you still cant download it pm me your email addy and i'll send it to you
[/edit]

[mjdee14]

Originally Posted by Happy|Harry

i can download it from here? i've tried to re-attach it to this post but the site wont let me saying that i have already attached it in post 14 of this thread

phil

[edit]
ok guys i've deleted it from the above post and re-attached it here, if you still cant download it pm me your email addy and i'll send it to you
[/edit]

Worked that time !

I really like it.....because of the pinions....and ratio...really nice to have it all on one sheet at the same time instead of having to re-input for each pinion..

Thanks guys...

Mike

[ke6d]

Originally Posted by Happy|Harry

dan it is indeed useful! though i've taken the liberty of modifying it to be as i mentioned above where you can input most of the values and get the resulting gear ratio and headspeed, with also calculations that take the drag coefficient into account. let me know what you think

phil

[edit]
i have attached the file in post no:17
[/edit]

No problem Phil. I am glad that you take your time and make it more useful. When I was selecting a motor/pinion, I just tabulated everything out so that I could decide which motor pinion to buy.

Thanks,

Dan

[tungym]

can someone confirm the reliabilty of the new 20T one-way pinion in 3D. thanks