X646/3 for 29" Sprint Cat on 6s?

[champion221elite]

Last year I ended up buying or horse trading for a B/S X646/3 for my 29" Sprint Cat that is a dedicated 6s boat. On paper, the pitch and diameter looked pretty good so I went ahead and grabbed it. The prop showed up and seeing it in person was a whole different story. While the prop was perfect (no complaints with the seller), it was quite a bit larger in pitch and overall blade surface than I was expecting. I normally run an M545 or X448 and the X646/3 is huge in comparison!

Needless to say, things got cool last Fall and the dock got pulled where I normally run my boat. I never had a chance to run things to give it a try. Looking at this big honking prop is giving me concern about being too much pitch/ blade surface.

My setup is a 1600 kv Leopard 4082 with 5.5 mm bullets used for the motor to esc, and battery to esc connections. ESC is a Sea King 180 v2. Batteries are 2x Nanotech 45c, 5000 mah, 3s packs wired in series for 6s. Normal runtime for the M545 is 2:15 with remaining cell voltage (no load) 3.75 volts on average.

Temps are usually in the 90 degree range for the ESC, and 120's for the motor after a 2:15 run. Average summer temps for the lake is in the low 80's so I don't get much cooling effect in July/ August. Temps are better in May/ June before the water gets too warm.

Will the X646/3 be too much prop, or will I be OK?

As always, thanks for the input.

[Tamelesstgr]

A 3-blade is generally going to put more load on your setup. Based on the OSE calculator 5000 mah and 135 second run time you are pulling about 130-135 amps with that M545. The 5.5 bullets are typically rated for 150 amp duty. While the ESC should handle the headroom of a larger prop, I am thinking a 646/3 is going to be getting really close in amp ratings, and possibly de-solder a connection. You can try it for 30 seconds or so and check temps, but I have generally heard if going to a 3-blade prop you should step down in overall diameter from the 2-blade you are running. Example, X442 2-blade, step down to X440 3-blade.

[champion221elite]

I figured it might be right on the edge of the systems safe limits.

Might just sell it in the classifieds since it's never been used at this point.

[dasboata]

Last year I ended up buying or horse trading for a B/S X646/3 for my 29" Sprint Cat that is a dedicated 6s boat. On paper, the pitch and diameter looked pretty good so I went ahead and grabbed it. The prop showed up and seeing it in person was a whole different story. While the prop was perfect (no complaints with the seller), it was quite a bit larger in pitch and overall blade surface than I was expecting. I normally run an M545 or X448 and the X646/3 is huge in comparison!

Needless to say, things got cool last Fall and the dock got pulled where I normally run my boat. I never had a chance to run things to give it a try. Looking at this big honking prop is giving me concern about being too much pitch/ blade surface.

My setup is a 1600 kv Leopard 4082 with 5.5 mm bullets used for the motor to esc, and battery to esc connections. ESC is a Sea King 180 v2. Batteries are 2x Nanotech 45c, 5000 mah, 3s packs wired in series for 6s. Normal runtime for the M545 is 2:15 with remaining cell voltage (no load) 3.75 volts on average.

Temps are usually in the 90 degree range for the ESC, and 120's for the motor after a 2:15 run. Average summer temps for the lake is in the low 80's so I don't get much cooling effect in July/ August. Temps are better in May/ June before the water gets too warm.

Will the X646/3 be too much prop, or will I be OK?

As always, thanks for the input.

send me the prop cover the shipping and I will reduce the diameter this will make it safer to turn

[ReddyWatts]

List for comparing the prop pitch. It can help in deciding which prop to try next.

PROP Pitch/inches

X437/3-- 2.072
X438---- 2.100
X440---- 2.198
X440/3-- 2.198
Y536---- 2.200
Y537/3-- 2.279
X442---- 2.310
X637---- 2.368
X445---- 2.478
X640---- 2.512
X447---- 2.590
X447/3-- 2.590
X642---- 2.640
M545---- 2.655
X448---- 2.660
X450---- 2.758
X450/3-- 2.758
X645---- 2.832
Y547---- 2.849
X548---- 2.850
X452---- 2.870
X452/3-- 2.870
X646---- 2.896
X646/3-- 2.896
X455---- 3.038
X455/3-- 3.038
X648---- 3.040
X457---- 3.136
X457/3-- 3.136
M650---- 3.190
X460---- 3.304
Y557---- 3.449
X560---- 3.540

X427---- 1.498 0.125
X430---- 1.652
X431---- 1.708
X432---- 1.764
Y531---- 1.877
X435---- 1.932
X632---- 2.016
Y534---- 2.059
Y535---- 2.125

[fweasel]

Great list. Thanks for posting that.

[champion221elite]

That list is very helpful. PM inbound Chris.