I Need Some Advise

[prismazan]

I owned a LRP V10 Spec 3 11T Quad and wanted to replace it in the outrigger. This is the general spec of the boat:

Length 20"
Width 16"
Prop 40mm - copper
Speed Ctrl MSC Tamiya
Batt NiCad 8 cell 2400mAh
RTR weight including battery and motor 500 - 1250grams

I started building the rigger from scratch after devoting some time in building RC plane. My present setup is a 500 stock motor and i found that the rigger does 6 - 8 mph only. I understand that replacing the motor is not the ultimate solution to improve speed besides the design but at least other setups such as sponsons, struts, prop, C.G etc were already fixed, changed or modified. The result was quite convincing but still below my expectation.

From observation, the rigger planes up to the front sponsons area only and never on the rear, leaving half look rooster tail at its max speed. I need some advise as whether by replacing the V10 will help and if so what are the consequences if i were to remain the general spec? or maybe doing some alterations to it?

[martin richards]

That 40 mm prop with an 11 turn motor sounds a sure way of emptying your batteries and doing a bit of on-board cooking for little effective speed. The motor needs to rev and the prop won't let it. Drastically reducing the prop size could lead to cavitation and your best option could be to fit a gearbox with 1.5 -2.0/1 reduction. The Hughey gearbox is one of the most popular.

[prismazan]

That 40 mm prop with an 11 turn motor sounds a sure way of emptying your batteries and doing a bit of on-board cooking for little effective speed. The motor needs to rev and the prop won't let it. Drastically reducing the prop size could lead to cavitation and your best option could be to fit a gearbox with 1.5 -2.0/1 reduction. The Hughey gearbox is one of the most popular.

Thanks Martin
I'm trying hard to figure out your explanation. As marine hardware are difficult to find in my country, i then have to outsource the left over gears from my grounded planes. Hopefully it will favor and pay off the effort.

Oh.. by the way I have just uploaded a poor slow motion rigger of mine for more comments. Pls check this out..

http://media.putfile.com/TestRiggerVid
:) rizal

[martin richards]

Rizal; I understand your problem's. It's hard finding things in Spain as well:(
Graupner seems to be the most widely available brand and have a good selection of carbon fibre props. There's no reason why a plane gearbox shouldn't work, but keep the ratios about 1.5 - 2.0:1 as the ratios for planes are usually higher.
Another point. 8 cells is probably pushing the motor too much; 7 or even 6 would be better.
I've seen your video. To be honest, a standard 500 (27t) motor and a 31 mm prop would at least triple the speed once the rigger is set up.