fuel tank

[ernest2]

hi! what is the right size for a .21 os rg-m engine? is it ok if the one i will buy will be for a rc car or an airplane? maybe helicopters. these are the only ones available in the hobby shops here. and hoe long is the run time?

thanks!

ernest

 

[Saugling]

Is the fuel tank for a Rigger / Cat / Mono???

I use airplane fuel tanks often, have no problems with them

I would buy something around 200ml, this will give you a runtime of about 7-8 minutes I think. Of course the size of the fuel tank also depends on your hull <_<

 

[ernest2]

my boat would be a catamaran. my problem is that most of the fuel tanks here are for cars which are small, maybe 80 cc only. i do like the flip top type because it will be easy to refill, even without a pump.

thanks!

 

[ernest2]

another question, what would be the diameter of the brass tube for a 3/16" flexshaft? and what is the best way to hold the prop shaft without using a strut? any homemade ideas>? there's no way i can buy a strut, so any brilliant ideas will be very welcome.

 

[wswatzell]

The John Finch Wild Thing is a strut-less design. What you do is take a 9/32" brass tube, & a 1/4" brass tube that just slips inside the 9/32" tube. This will give you the strength you need. Then make a bushing by taking a short (about 1/4" long) piece of the 1/4" tube & solder it to the outside-end of a 3" long piece of 7/32" brass tube. Drill a series of holes along the length of the 7/32 tube to hold the grease. Then slip the bushing inside the 9/32-1/4 doubled tube. The 1/4" long piece of brass that you soldered to the end of your bushing acts a bushing stop, as well as a thrust bushing. I can take some pics & post them later if it helps

 

[ernest2]

hi! just finished cutting the frames, gotta get some sleep and assembly it tomorrow after work.

thanks! i've seen that in rcbm website, and studied a bit. the thing though is that i'm building a catamaran, so it doenst have support unlike in the mono. i'm still thinking of a way though.

thanks!!

ernest

 

[wswatzell]

You could always build a pod that hangs down under the hull between the sponsons that would support the stuffing tube. Just keep it high enough to be above the waterline when on plane. Another solution would be to fabricate your own strut by brazing a 1/4" brass tube to a brass plate that you mount to the transom using angle brackets. Then make a bushing the same way I described earlier.

 

[ernest2]

ok thanks! maybe i'll try making a strut by using a brass door hinge, i'll see if the hole in the hinge fin fits with the brass tube as you described.

thanks!

 

[wswatzell]

make sure it isn't too heavy. the brass on the door hinges are rather thick.

 

[ernest2]

yup thick, maybe if i go wih it, i have to thin it a bit.

another thing, what is the CG of a catamaran? is it the same with deepvee? i understand that DV's have their CG at 1/3 from transom.

thanks!