70" CRC Outerlimits Build
#27
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#28
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So what is a proper steering servo to use? I bought a Hitec HS-805MG 1/4 scale, but dog gone this thing is huge! Is there something you all might have recommended instead?
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That is a tad bit bigger than most 1/4 scale servos so you may have a little trouble finding a servo tray to fit it. I know the Speedmaster 1/4 scale servo tray will be a little too small for it. I have used the Hitec HS-5755MG and HS-5765MH in most builds and they barely fit the Speedmaster 1/4 scale trays with little or no room to spare. Lately I have been using the Futaba S9157 for steering which is a standard size servo but with 425oz. torque @ 6v. You can also use the Futaba S5302 1/4 scale servo.
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She's here!sitting next to my 70" fountain. For CG should I subtract the 5" transom over hang? Recommend 30% for CG? I ask cause I know a few on here have built this beast.
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Personally i would NOT recommend a 30% COG with that hull. The hull will run very wet and you would not be pleased,especially if you don't run in salt water. From my experience running and building many GTX hulls and knowing what COG changes Mike had to do to his 70" Outerlimits with single mod Gizmo 29cc motor in order for it not to run so wet i would recommend between 25% - 26" COG and nothing more.
#38
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Depending on the tabs and the boat - most mono's I've done with single tabs the edge starts at least 2" from center of transom
Not sure with that hull but those are pretty close I'd move them out
RD
One of my favorite boats
Not sure with that hull but those are pretty close I'd move them out
RD
One of my favorite boats
Last edited by mistycreekboats; 06-05-2014 at 10:18 AM.
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2 1/2" from keel to inner edge of tab will be fine. That's the measurement I'm used on 2 of 4 GTX hulls I'm built and the Outerlimits is the same bottom. My personal GTX was 3" to inner egde but I noticed no difference in handling in calm or rough water conditions.
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Got some work done on the hull this weekend. Only thing left is to add the T-bar and oilier, Hard mount the radio box, & connect the linkages for throttle and rudder - then get some testing in.
Here are a few pics.
Here are a few pics.
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Looking good but a few suggestions....
Turn exhaust cooling flange around so hoses enter and exit from front. Waterline from rudder you want enter from bottom on flange and exit from top. I would also move water outlets in front of pipe header. That way you stand less chance of hoses touching pipe and burning a hole in water line.
You have plenty air in but little ventilation out of hull. General rule of thumb is 1:3...so you want 3 times as much ventilation exiting the hull. You can get away with a 1:2 ratio though. If you don't want holes to be seen cut them in bottom side of overhang.
Also turn your full tank around so when bow lifts and tank is low it will still be forced towards fuel pickup. The way it is now,if tanks runs low while getting bow lift the fuel will be going away from fuel pickup and it will loose fuel suction.
Turn exhaust cooling flange around so hoses enter and exit from front. Waterline from rudder you want enter from bottom on flange and exit from top. I would also move water outlets in front of pipe header. That way you stand less chance of hoses touching pipe and burning a hole in water line.
You have plenty air in but little ventilation out of hull. General rule of thumb is 1:3...so you want 3 times as much ventilation exiting the hull. You can get away with a 1:2 ratio though. If you don't want holes to be seen cut them in bottom side of overhang.
Also turn your full tank around so when bow lifts and tank is low it will still be forced towards fuel pickup. The way it is now,if tanks runs low while getting bow lift the fuel will be going away from fuel pickup and it will loose fuel suction.
#43
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Fantastic suggestions - I actually have 4 more air duct coming from MHZ Germany, just waiting for them to get here. My plan was to mount them on the under side of the transom over hang. Took your suggestion and re-routed the water cooling lines as you stated
I'm not sure I understand your suggestion regarding the fuel tank...The way I have it positioned, the fuel pick up/clunk is at the back of the tank near the engine. Shouldn't that be correct?
Any suggestion on how to mount the radio box vs. just sending some screws threw it into the engine rails?
Thanks again for all the help!
-BG
I'm not sure I understand your suggestion regarding the fuel tank...The way I have it positioned, the fuel pick up/clunk is at the back of the tank near the engine. Shouldn't that be correct?
Any suggestion on how to mount the radio box vs. just sending some screws threw it into the engine rails?
Thanks again for all the help!
-BG
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Ok if you have the clunk at the back your in the right direction. With the radio box you can get two small hooks from hardware store an screw into engine rails that way you just hook your rubber bands from one hook to the other hook on opposite side and your good. You can put a rubber mount at front of radio box to stop from moving forward. Or a small square pice of wood with a 6/32" or 8/32" nut and bolt holding it to engine rail.
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Tabs moved out, pipe outlet added, servo line added, and drive line done. Now I'm just waiting on my last couple of air vents to get here from Germany and she is ready for testing! Then a nice paint scheme.