difference in prop types
01-19-2013 | 06:47 PM
#1
Thread Starter
My Feedback: (12)
Joined: Dec 2001
Posts: 389
Likes: 0
Received 0 Likes
on
0 Posts
From: Yellow Springs,
OH
difference in prop types
not sure if this is the right forum to put this in but what is the difference between all the different types of wooden props. I have seen type a, c, d, and e. I was wanting to order a new prop for my os 70 4 stroke and wasnt sure the difference between all the props.
thanks
Jeff
thanks
Jeff
01-19-2013 | 07:12 PM
#2
Senior Member
RE: difference in prop types
Not all props are created equal to put it simply. In general wide bladed props work best with 4 stroke engines while narrow blades work well with screaming 2 strokes. However it seems there are no hard rules, I prefer to grab a handful of props in the general size range and fly each one then decide.
01-20-2013 | 07:43 AM
#5
Senior Member
RE: difference in prop types
Depending on the drag factor of the airframe the engine is to be used in, I prop about 700-1500 RPM less (static) than the maximum RPM of the engine.
If the engine is to be installed in a WW-I biplane start W/the smaller spec'ed props. If it's going into a P-51 Mustang, go W/the larger spec'ed props.
If the engine is to be installed in a WW-I biplane start W/the smaller spec'ed props. If it's going into a P-51 Mustang, go W/the larger spec'ed props.
01-20-2013 | 09:05 AM
#6
Senior Member
Joined: Mar 2003
Posts: 6,544
Likes: 0
Received 0 Likes
on
0 Posts
From: Garland, TX
RE: difference in prop types
I like a 13x6 Master Airscrew K Series on my 70 four stroke. As already stated, try a few to see what you like.
edit
the K series is plastic, didn't read the original post very well
edit
the K series is plastic, didn't read the original post very well
01-22-2013 | 08:42 AM
#7
Senior Member
RE: difference in prop types
Iuse 10,000 rpm as a limit for static rpms on any prop for mid sized 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
01-22-2013 | 11:11 AM
#8
Senior Member
RE: difference in prop types
ORIGINAL: jeffie8696
I use 10,000 rpm as a limit for static rpms on any prop for mid sized 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
I use 10,000 rpm as a limit for static rpms on any prop for mid sized 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
My CDI fired Saito FA91S was spinning a 15 x 4 @ 10,300, a bit more than I liked.
I went to a 15 x 5 & the revs dropped to 9,700, a bit more cushion against overreving in the air.
01-22-2013 | 04:11 PM
#9
RE: difference in prop types
ORIGINAL: SrTelemaster150
That's a good bench mark for medium sized 4-strokes.
My CDI fired Saito FA91S was spinning a 15 x 4 @ 10,300, a bit more than I liked.
I went to a 15 x 5 & the revs dropped to 9,700, a bit more cushion against overreving in the air.
ORIGINAL: jeffie8696
I use 10,000 rpm as a limit for static rpms on any prop for mid sized 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
I use 10,000 rpm as a limit for static rpms on any prop for mid sized 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
My CDI fired Saito FA91S was spinning a 15 x 4 @ 10,300, a bit more than I liked.
I went to a 15 x 5 & the revs dropped to 9,700, a bit more cushion against overreving in the air.
01-22-2013 | 04:36 PM
#10
Senior Member
RE: difference in prop types
ORIGINAL: 1QwkSport2.5r
Whats the typical rev range for the average OS or Saito 4-stroke?
ORIGINAL: SrTelemaster150
That's a good bench mark for medium sized 4-strokes.
My CDI fired Saito FA91S was spinning a 15 x 4 @ 10,300, a bit more than I liked.
I went to a 15 x 5 & the revs dropped to 9,700, a bit more cushion against overreving in the air.
ORIGINAL: jeffie8696
I use 10,000 rpm as a limit for static rpms on any prop for mid sized 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
I use 10,000 rpm as a limit for static rpms on any prop for mid sized 4S engines.
In other words I ground test any prop I am interested in trying and if it turns over 10,000 static it might over rev the engine and cause wear, stress on the engine.
I allow slightly higher rpm limits on smaller 4S engines.
My CDI fired Saito FA91S was spinning a 15 x 4 @ 10,300, a bit more than I liked.
I went to a 15 x 5 & the revs dropped to 9,700, a bit more cushion against overreving in the air.
Mine idles @ 1700 RPM W/CDI firing things off 11* BTDC @ idle.
Initial full advance timing setting is 35* BTDC.
