Engine Conversions Discuss all aspects of engine conversions in this forum

Prop hub type for 25 cc two stroke.

Reply

Old 11-14-2018, 02:31 AM
  #1  
Jim.Thompson
Thread Starter
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 225
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Prop hub type for 25 cc two stroke.

I am converting a Chinese 2 stroke 25 cc engine. I plan to machine the prop hub. However, I don't know what type is suitable for this size engine.
By that I mean, is it customary to make and fit a 4 bolt type with a centre spigot? Or just a single threaded shaft to retain the prop.
Can someone advise please?
I am planning on trying a 17 x 6 wood prop for starters.

Jim.
Jim.Thompson is offline  
Reply With Quote
Old 11-14-2018, 07:45 PM
  #2  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Sacramento, CA
Posts: 6,529
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Jim, I would lean towards the single bolt hub. It will secure the prop just fine and you may find that the use of a 4 bolt hub would greatly reduce your prop selection. I don't think there are too many props that small that would have a large enough hub for 4 bolts. The only challenge may be getting it to run true but based on other projects I have seen you take on here and on RCG I confident you are up to the task.
speedracerntrixie is online now  
Reply With Quote
Old 11-14-2018, 09:20 PM
  #3  
Jim.Thompson
Thread Starter
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 225
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Originally Posted by speedracerntrixie View Post
Jim, I would lean towards the single bolt hub. It will secure the prop just fine and you may find that the use of a 4 bolt hub would greatly reduce your prop selection. I don't think there are too many props that small that would have a large enough hub for 4 bolts. The only challenge may be getting it to run true ........................
Thanks Speedracerntrixie,

That more or less confirms my thinking. I am confident about the centreing for true running. We how have a good dial gauge and stand for the old lathe in our local "Mens Shed".
I will purchase the prop first to get the boss outside diameter and the centre hole size before doing anything about it.
Thanks for the reply.

Jim.
Jim.Thompson is offline  
Reply With Quote
Old 11-15-2018, 12:56 AM
  #4  
Jim.Thompson
Thread Starter
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 225
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default


After a quick discussion with a engine rebuilder buddy of mine, I/we came up with this possible configuration for the manufacture of a prop hub for this little motor.
I will attach a quick draft. Mainly for discussion purposes.
And if alternative design concepts are in popular usage, I hope someone will post details etc.

Jim.
Jim.Thompson is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service