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View Full Version : NICAD VS LIPO in a Standard SIG Rascal


confuqua
11-21-2005, 12:56 AM
I am putting together a Sig Rascal which will be powered by a 6v SP400. The kit came with the motor, and a 20 amp esc. They recommend a 7 cell Sanyo KR-600AE battery pack (which will deliver 8.4 volts and weigh somewhere between 4.5 and 5 ounces).

Is there any reason not to substitute a 2 cell Kokam 2000 mAh pack (which will deliver 7.4 volts and weigh about 4 ounces)?

It would seem to be an easy way to increase flight time.

Frank

Twmaster
11-21-2005, 01:02 AM
There is no reason not to use the lipo -except- that the included ESC is not lipo aware for the voltage cutoffs. If you were to get a Castle Pixie 20 or one of the new Great Planes lipo compatible ESC's then you would be set.

I have flown the Rascal with 8 cell NiMHs and it flys great although lighter is usually a good idea.

confuqua
11-21-2005, 04:38 AM
Thanks for the reply! I had forgotten about the LIPO voltage cutoff requirement. An appropriate ESC is now in the future of this model.

Frank

Will Hicks
11-21-2005, 10:41 AM
FMA makes a LVC unit that can be added to any ESC. The unit installs between the ESC and the receiver. A power wire is install on the battery positive lead.

You may see one at this link:

http://willstech.com/products/product_info.php?cPath=45&products_id=654&osCsid=ae3db59758e3925659349f4769ad0b93

tim hooper
11-21-2005, 06:15 PM
Frank,

ESC issues aside, you may want to check where the battery is in relation to the CG. If the model needs the weight of the 600AE's to balance correctly, then there's no point in fitting Li-pos, as you'll need to add ballast.

There are far better cells than the 600AE around these days - check the GP1100s or KAN 1050s.

tim

RodJim
11-21-2005, 07:01 PM
Frank, I have flown the Rascal C for a number of years on an 8 cell 950 mah Kan battery and have been happy withthe performance. I have a 2:1 geared Speed 400 and use a 9x4.5 or 9x6 APC E prop. I switched this past year to a Kokam 3S 1500 Li-Po battery and find that I have better performance. This is probably due to the reduction in weight of 2.7 oz (or 76 gms.) I also have longer motor runs due to the increase from 950 to 1500 mah. I have used a Li-Saver and find that they work well with standard ESC's

Mike Freas
11-21-2005, 08:38 PM
There is no reason not to use the lipo -except- that the included ESC is not lipo aware for the voltage cutoffs. If you were to get a Castle Pixie 20 or one of the new Great Planes lipo compatible ESC's then you would be set.

I have flown the Rascal with 8 cell NiMHs and it flys great although lighter is usually a good idea.

Not to hijack the thread but where in Laurel do you live? I grew up in good old Laurel!

walterk
11-23-2005, 12:26 AM
Frank

I have a Sig rascal. I have been flying for about 3 years now. This last year I switched to a 3s LiPo 1100mah battery. I am using the same esc and 7.2 volt motor. I switched the gear ratio to 2:1. The prop is a 9x6 APC. It finally has reasonable performance. I can take off and land. I am using 2.75 " light wheels. I have over 50 flights on the moto since I switched to the LIPO at it seems to like it better than the 8 cell NiCad pack I originally used.

Walt

confuqua
11-23-2005, 12:45 AM
Walt, that's great information. What flight times do you get with that setup?

Frank

TeslaWinger
12-12-2005, 11:13 PM
I have the Lil Rascal, the 29.7" span version and love that lil bird! I will most likely get the larger version in the future since it is one of my favorite powerplanes.

I recently switched it to a CD Rom motor I got in a trade with a 1200 maH 3 cell lipo (the previous 700ma 3 cell lipo was no slouch either, but got swiped for a wireless cam project)- altho the stock Speed 180 w redrive hauled it just fine.

Part cub, part 'fighterplane', it is a testimony to a clean eliptical wing and a seriously snarky fuse. I have yet to fly it 'dry' since at 4 amps- and all the power you could ever want, it outlasts me!

Your use of a 7.2V S400 with a 3 cell (I like the 1500 ma size for S400) will give you great performance- just get air thru that motor since it pushes the motor hard- but you can have a boxload of extra S4oos for the price of a brushless and still get faboo performance! Wotta Wascal! :D

walterk
12-12-2005, 11:43 PM
Frank

Sorry for not getting back to you sooner. I don't always check the posts. I get over ten minutes on my flights but I don't push it because I don't have a LiPo ready ESC. I usually don't fly full throttle the whole time but I have plenty of power to take off and land as much as I want.


Walt