Weight & Voltage reduction vs Prop?

[SJFE]

Last time out in the jolly I ran 16 nihm's @ 19 volts on the K42 @ 8 pounds total weight. The temps where more than I like to see. Now I received my lipos from Dooz. I have a set of 25c 4s-1p 14.8v 3300mah lipos @ neer half the weight. Ok so heres my qustion. Can I run the same prop @ the lower weight and volage get better results or will I have to prop up to a k45? I'm kinda lost here guys.
Thanks,
Tom

[Jeepers]

I would try the 42mm prop first that way you can see were your temps are, your pullin 1800kv right? you should be close to 40s on that set up.

[NorthernBoater]

In my Jolly Cat I plan on putting some weight in the back when running with LiPos. A LiPo pack is not as long so the weight is not going to be spread out as much like it would be with a pack of NiMh cells. Hopefully this will keep the back down better.

[SJFE]

Yep 1800kvm. So your saying stick with the k42 for the first lipo run. Ok. I will need to drop to a 40mm prop for the nimh runs. I have the grimm 3blade and a k40 I will try. I have a couple v900s but have been warned off them. I refernce to the CG I am moving the ni packs back an inch to fly the hull a little beter. I'll move the lipos way up but I dont plan to add weight. I'm willing to swim...lol

[Fluid]

...Hopefully this will keep the back down better.

Tell me how/why you feel that the stern is not down far enough. In a cat this is almost unheard of.
* CG % from sponson transoms (not the extreme back of boat)?
* Prop used?
* Strut depth relative to the sponson bottoms?
* Strut angle relative to sponson bottoms?


.

[Jeepers]

Yep 1800kvm. So your saying stick with the k42 for the first lipo run. Ok. I will need to drop to a 40mm prop for the nimh runs. I have the grimm 3blade and a k40 I will try. I have a couple v900s but have been warned off them. I refernce to the CG I am moving the ni packs back an inch to fly the hull a little beter. I'll move the lipos way up but I dont plan to add weight. I'm willing to swim...lol

If you have a 40mm prop go with that first then work your way up.

I am turning 1860kv in my mono and a x640 detounged, and its a handful on 4s. you might find that the smaller props some times work better.

[SJFE]

Thanks Bud...I didn't get out yesterday. I'm hoping the weather holds off this afternoon for a run or 3. :)

[NorthernBoater]

Tell me how/why you feel that the stern is not down far enough. In a cat this is almost unheard of.
* CG % from sponson transoms (not the extreme back of boat)?
* Prop used?
* Strut depth relative to the sponson bottoms?
* Strut angle relative to sponson bottoms?


.

What I mean was I was getting to much lift. I am not going to change were the CG is. If all of your weight is closer to the CG it is easier for the prop to generate lift. With the Jolly Cat you can not change the strut angle or depth with the one with hardware.