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Lightknight
01-14-2016, 05:34 AM
I have just finished a Hydro & Marine T5 build and running a SK 180 and a Leo 4092 1730 on 6S.

I have been playing around with props and I am having some problems. I have an M545 which is ok and a M645 (which works well with other hulls) too but that seems marginal as does a Prather 225. I tried a V942 and just could not get it working. It eventually sheered all 3 blades off... A Prather 220 seems about the best so far but it doesn't excite me . I am thinking that a 3 blade .6 or .7 pitch would be good but after the experience with the V series I have been counting the hours spent sharpening and balancing. Any thoughts?

Fluid
01-14-2016, 04:15 PM
Your props are all too small for that large hull, poor efficiency. An x450 or x452 two-blade should be more in the ballpark, properly set up you should be close to 70 mph. Properly set up is the key here, watch temps carefully until you know that the prop is okay. The motor Kv is a bit high for a sport 6S hydro especially if you have limited sized water to run on.



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Lightknight
01-14-2016, 06:39 PM
Fluid, thanks for your reply. That is interesting in that the pitch of the 450 being 0.4 puts it between the M645 and the M545 and almost identical with the Prather 225. Do you think prop diameter is more important to getting the performance?
Yep the KV in a bit high. We don't have any real size limitations and we race on an approx 400 meter oval. (salt water, so a bit more buoyancy) - the main issue is wind and choppy water.

Fluid
01-15-2016, 02:15 AM
Pitch is not so important, diameter is. A 45mm prop is just too small for that hull regardless of the pitch. It will have too much slip and thus very poor efficiency. Most of us who race Q Sport boats use at least 50mm props and have good speed and run time. A 50mm prop has at least 30% more blade area compared to a 45mm, which is enough to transfer the motor energy to the water. A 45mm is okay on a smaller 4S hydro but has too little blade for decent efficiency with a heavy boat and 6S power.


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Lightknight
01-15-2016, 03:46 PM
Fluid, many thanks: I've got it.

Shooter
01-17-2016, 10:52 PM
A lot of us are running 1527-1Y (1250KV) and we use X452's and X455's.

Fluid
01-17-2016, 11:12 PM
A lot of us are running 1527-1Y (1250KV) and we use X452's and X455's.
FAR different Kv values. What works on a 1250 Kv motor will be too much for one with a Kv of 1730.


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Lightknight
01-20-2016, 01:09 AM
So I tried a 450 belonging to a friend: accelerated across the lake and lost the prop after the shaft broke just by the flex and stub. Embarrassed :-/
Just prior it had been running reasonably quick on a Prather 230.

Lightknight
03-23-2016, 10:58 PM
Still searching for the perfect prop!.I have come to the conclusion that I need to reduce the KV or get a bigger ESC.
As it is, running a 5014/3 CNC prop I am getting around 120 KPH and overheating everywhere. If I come down to 4814/3 - motor temps are fine but ESC temp is borderline at best and full race distance without thermalling the ESC is problematic unless I come down to a 4614/3. I am about to try a ABC 1816 3 blade cleaver which I think should be the sweet spot for the motor. Long term I reckon a TP 4070 5D and a swordfish 240 Amp will be the way to go.

T.S.Davis
03-24-2016, 06:07 AM
You made a quantum leap from a 645 to a 50 mm 3 blade. A 50mm 2 blade will likely get hot with that many kV.

Lightknight
03-24-2016, 07:00 PM
Certainly in blade area if not total pitch: that 6 pitch takes some turning at low-medium speed. I also tried a 48 3 blade: pretty similar to the 50 just less which is hardly surprising. A lot of people have said to me - and I agree with them -that the T180 V3 is not as load tolerant as V2 - due in part to the sacrifice of cooling pipes in favour of capacitors. Leopard quotes the 4092 3D as drawing a max of 140 amps. Not so - a referral to ohms law shows it draws a max of 210 amps , so what I am saying is I think the a 48 would work with something like a swordfish 240.

detox
03-26-2016, 03:21 PM
A lot of us are running 1527-1Y (1250KV) and we use X452's and X455's.

I used X455 on my Q Whiplash. The tongue really helps jump on plane quickly and exiting the turns. Trimming the tongue back a little and adding a small amount of cup to the tips should do wonders.

I have seen hulls slow badly in the turns...lack of tongue is the major cause.:tongue_smilie:

nichismo
03-27-2016, 09:02 AM
lol the only props Ive ran on my 45" 1/8 T5 were x450 2 and 3 blades, the thing was about 15lbs RTR and it still ran about 45-50mph with an 800kv motor on 8s.

I cant imagine a 1700kv on 6s with the same size prop with that hull!

Lightknight
03-28-2016, 03:36 AM
Yeah 1730kv is a lot for a Q. It's "only" 36" and 11 lbs RTR but a 455 is not what this setup is about.... As it is the speed I am getting with a Prather 230 or a 4814 3 blade is plenty.

K.R.Joye
04-22-2016, 09:33 AM
I run a 1717(1580kv) on 6S in my Whip like Q-Sport. Detounged X447 gets going into competitive speed territory with no cooling on the motor.

ray schrauwen
04-22-2016, 11:42 AM
I run a 1717(1580kv) on 6S in my Whip like Q-Sport. Detounged X447 gets going into competitive speed territory with no cooling on the motor.

Not even Ed Hughey style air cooling? Wow.

ray schrauwen
04-22-2016, 11:43 AM
I used X455 on my Q Whiplash. The tongue really helps jump on plane quickly and exiting the turns. Trimming the tongue back a little and adding a small amount of cup to the tips should do wonders.

I have seen hulls slow badly in the turns...lack of tongue is the major cause.:tongue_smilie:

Interesting. Thx.

Lightknight
04-24-2016, 05:56 PM
No cooling!
I have recently upgraded from a T180 to a Swordfish Pro 240 HV. Most of the time the Leopard is pulling around 160 Amps but there are quite a few peaks around 220-240A. I cant imagine running without water cooling....142660 Image shows the combo of an ABC 1816 CLL and Leopard 4092 1730 KV.