UL power plant

[ice329]

Can people who have the UL and ran both the SV power plant and the UL, tell me what and how much of a differnce you think there is... is the UL's as torky as the SV's etc How about efficiantcy etc. Thanks

[sailr]

There is a TON of difference in the SV27 and UL-1 motors. The UL-1 motor puts out a LOT more power. There is a big argument going on in the LSH tech class about it. I personally object to people putting the UL-1 motor in their boat and saying it's the same as a SV27! Not fair.

[Darin Jordan]

There is a TON of difference in the SV27 and UL-1 motors. The UL-1 motor puts out a LOT more power. There is a big argument going on in the LSH tech class about it. I personally object to people putting the UL-1 motor in their boat and saying it's the same as a SV27! Not fair.

This is actually NOT true... it doesn't put out "more power"... it puts out similiar power in a different way.

The Higher KV comes at a price. I've load tested the UL1, BJ26, SV27, and HiMax 3630-1500 motor (basically the same as the BJ26) on a test bench, recording amps, thrust (with a given airplane prop), watts, etc...

Using the SV27 and UL1 motors, with the same load, the UL1 motor pulls 39-amps and drops down 4800 RPM over it's unloaded RPM, compared to only 26-amps and a drop of only 1569 RPM for the SV27 motor, again, using the exact same load and battery setup. This should tell you that the SV27 motor can take a LOT more prop before it reaches it's amp limit, while the UL1 motor is already approaching it's...

I think what you'll find is that there are some applications where the SV27 motor would actually have an advantage, and others where the UL1 motor would be preferred.

If you have a light hull that likes a smaller prop spinning fast, then the UL1 would work well. If you have a larger, or heavier hull, that can handle the torque and a larger prop, you might have an advantage with the SV27 or ProBoat BJ26 setup...

[sailr]

Obviously the lower KV motor in the SV27 will handle a bit bigger prop. Appreciate your tests. Very interesting. My observations were in practical application in the boats.

[ice329]

Lets take the TS2 similer to like we all built with the SV motor on a outboard would the TS2 benifit from the UL motor. Maybe this was a better question.

[sailr]

Outboard applications require smaller props so in that case, the UL motor might be better. The only reason I have ever figured out the leeetle props on outboards is the extra drag of the small radius in the bend of the flexshaft. Not sure.

[sailr]

Darin,
Isn't the UL-1 motor a 4 pole as opposed to 2 pole in the SV27? Seems like I read that but could be wrong.

This is actually NOT true... it doesn't put out "more power"... it puts out similiar power in a different way.

The Higher KV comes at a price. I've load tested the UL1, BJ26, SV27, and HiMax 3630-1500 motor (basically the same as the BJ26) on a test bench, recording amps, thrust (with a given airplane prop), watts, etc...

Using the SV27 and UL1 motors, with the same load, the UL1 motor pulls 39-amps and drops down 4800 RPM over it's unloaded RPM, compared to only 26-amps and a drop of only 1569 RPM for the SV27 motor, again, using the exact same load and battery setup. This should tell you that the SV27 motor can take a LOT more prop before it reaches it's amp limit, while the UL1 motor is already approaching it's...

I think what you'll find is that there are some applications where the SV27 motor would actually have an advantage, and others where the UL1 motor would be preferred.

If you have a light hull that likes a smaller prop spinning fast, then the UL1 would work well. If you have a larger, or heavier hull, that can handle the torque and a larger prop, you might have an advantage with the SV27 or ProBoat BJ26 setup...

[Darin Jordan]

Darin,
Isn't the UL-1 motor a 4 pole as opposed to 2 pole in the SV27? Seems like I read that but could be wrong.

No... they are both 6-pole motors...

As for the outboards... we run props up to X447s, X646's, and Prather 230s on our OPC tunnels... The FE motors require WAY more prop than the Nitro guys can run...

I agree that the UL-1 motor may be a better choice for Sport Hydros, Riggers... The jury is still out on the OPC tunnels and Monos...

For example, I run a 42mm prop on my SV27 powered OPC, but it's pitched WAY up, and started life as an X645...

Another summer of play and we'll have it all figured out... just in time for a new offering to emerge!

[detox]

Thanks Darin, The SV27 motor/esc does seem to hold up better to larger props such as a 2047 in my Rigger Insanity. I have already destroyed one UL1 esc (swollen cap) swinging a detunged x645 in my UL-1.

I may try the SV 27 motor/esc combo in my UL-1 next.




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[Rumdog]

Have you ever done any testing with the Ammo motors? I purchased a ammo 38-56 2600kv. gonna give it a whirl in my UL-1 this spring.

[ice329]

I guess someone has to put 2 exactly the same boats side by side on the water with the same prop and see which one is faster.

[Fluid]

I guess someone has to put 2 exactly the same boats side by side on the water with the same prop and see which one is faster.

That test would not prove which is 'faster', it would be a waste of time. One motor may need a smaller diameter prop but can handle more pitch at a higher rpm - the other motor may be able to swing a lot of blade area but with less pitch and at a slower rpm. You would need to test different props on each motor in the same boat to find the one with the fastest top speed.

An example - the top two P Sport Hydros in our club are equally fast, one runs a Neu 1515/1Y and the other a Hacker 9XL - very different motors. They use different props, but their performance is almost identical.

Remember that the fastest top speed is not all that we are worried about. If the SV motor needed a 47mm prop to be the fastest, that may cause handling issues that the boat can't overcome. Then it could all be different in another hull type. It is not as simple as a direct side-by-side comparison.


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[sailr]

I try to find the best 'compromise' prop and then 'tweek' the strut depth and angle, CG, etc. to get the best running attitude of the boat. Highest speed is not always the answer! You may be fast as hell but the boat is uncontrollable so what's the point? You may have a docile boat but the speed sucks....so, once again, what's the point?

There is a lot more than JUST props that go into making a competitive racing boat but it's certainly the best place to start.

[Darin Jordan]

There is a lot more than JUST props that go into making a competitive racing boat but it's certainly the best place to start.

I'd say exactly the opposite... It ALL comes down to the prop!

We could all throw a 2047 on a UL1... but I'm guessing maybe 2 or 3 of those that try would get the boat anywhere NEAR 63mph...

[sailr]

You totally misunderstood my post! I'm surprised by your response. PROPS ARE CRITICAL but not the ENTIRE solution! If you're going for SAW's, that's one thing. If you want to win races, that's another entirely.