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Got bitten by the racing bug at last years first Legg Lake SAWs. But I wanted to build a non SAW, regular T class Offshore race boat that is both strong and great handling. I settled on the Avenger Pro cat hull. The plan is to be finished in a week or so, ran, tested and setup for the NAMBA Nats at Legg Lake this June.
This is the first post & pictures of my on-going build. You may have ran across across my rants on other threads about using seamless Stainless Steel stuffing tubes w/o teflon liners. Note: I walk the walk. But, this drive line build was a tough one. First, the .375 OD X .267 ID tubing had to be reduced at the strut end for a slide-in fit. Cuz I'm not a machinist or have access to a lathe, I chucked the tube in my trusty hand drill & GENTLY ground the tubing on the side of my bench grinder. Used lots of WD40 to keep it semi-smoothe until it almost fit into the strut. Did the final metal removal with a bench mounted flap wheel, and buffed on a rouge wheel as the final step.
Bending the proper curve in the SS proved tougher than I expected, so I used a soft rubber mallet and a doormat to GENTLY bend the tubing starting about 4" from the strut end. Earlier, I had mounted the modified gas engine motor mount, cut the shaft slot in the hull, and firmly positioned the strut flat with the hull bottom to make alignment easier. Bend - check alignment - Bend - check alignment Bend - check alignment
. Any one who has installed & aligned a stuffing tube/strut/motor realize this is a combination of science and art. Took awhile but it came out pretty cool
Before I could fiberglass the stuffing tube to the inner deck, I needed a way to keep the shaft perfectly aligned with the motor shaft while the epoxy dried. My solution was to use a 1/4" thick piece of scrap ash plywood to support & hold the tube in place. First I sanded a V shape with a bottom taper with a 90 degree angle with the tube. Cuz there was a lot of adjustment room, I drilled a 3/8" tapered hole in the the plywood at roughly the same angle as the prop shaft. To make shaft/motor alignment easier, I drilled two small holes in the top side of the shaft mount before cutting the mount in half, and installed the lower half in the hull with Super Glue - followed with epoxy. While the lower half dried, I enlarged the holes the upper half to clear the SS hex screws. Once lower half setup, the top half was screwed to the lower half, screws removed, a few drops of CA added to firm up the threads, then both were screwed together.
Before the final fiberglass/epoxy was layed to hold the stuffing tube in place, I applied a thin layer of Lithium grease to the shaft to make replacing it (if needed) easier. Finally, I used several layers of flexable fiber glass cloth and epoxy to hold the tube in place. From the pics, you can see finishing glassing the tube slot in the hull bottom is next. Gonna use epoxy thickened with glass beads for that. No cloth.
The strut itself is a bit unusual - with a double edged razor sharp <> shape, and has a single 3/16" ID needle bearing at the prop end. Theory is it will slice through the water and have minimal driveline friction.
The offset rudder has dual H2O pickups, and will most likely be moved closer to the strut after testing.
Motor is a Leopard 5692 1090KV, and will be running 10S2P for testing. Have 730 & 1320 KV motors as alternates.
ESCs are Castle HYDRA ICE-2 200HVs.
More later..................
JIM
This is the first post & pictures of my on-going build. You may have ran across across my rants on other threads about using seamless Stainless Steel stuffing tubes w/o teflon liners. Note: I walk the walk. But, this drive line build was a tough one. First, the .375 OD X .267 ID tubing had to be reduced at the strut end for a slide-in fit. Cuz I'm not a machinist or have access to a lathe, I chucked the tube in my trusty hand drill & GENTLY ground the tubing on the side of my bench grinder. Used lots of WD40 to keep it semi-smoothe until it almost fit into the strut. Did the final metal removal with a bench mounted flap wheel, and buffed on a rouge wheel as the final step.
Bending the proper curve in the SS proved tougher than I expected, so I used a soft rubber mallet and a doormat to GENTLY bend the tubing starting about 4" from the strut end. Earlier, I had mounted the modified gas engine motor mount, cut the shaft slot in the hull, and firmly positioned the strut flat with the hull bottom to make alignment easier. Bend - check alignment - Bend - check alignment Bend - check alignment
. Any one who has installed & aligned a stuffing tube/strut/motor realize this is a combination of science and art. Took awhile but it came out pretty coolBefore I could fiberglass the stuffing tube to the inner deck, I needed a way to keep the shaft perfectly aligned with the motor shaft while the epoxy dried. My solution was to use a 1/4" thick piece of scrap ash plywood to support & hold the tube in place. First I sanded a V shape with a bottom taper with a 90 degree angle with the tube. Cuz there was a lot of adjustment room, I drilled a 3/8" tapered hole in the the plywood at roughly the same angle as the prop shaft. To make shaft/motor alignment easier, I drilled two small holes in the top side of the shaft mount before cutting the mount in half, and installed the lower half in the hull with Super Glue - followed with epoxy. While the lower half dried, I enlarged the holes the upper half to clear the SS hex screws. Once lower half setup, the top half was screwed to the lower half, screws removed, a few drops of CA added to firm up the threads, then both were screwed together.
Before the final fiberglass/epoxy was layed to hold the stuffing tube in place, I applied a thin layer of Lithium grease to the shaft to make replacing it (if needed) easier. Finally, I used several layers of flexable fiber glass cloth and epoxy to hold the tube in place. From the pics, you can see finishing glassing the tube slot in the hull bottom is next. Gonna use epoxy thickened with glass beads for that. No cloth.
The strut itself is a bit unusual - with a double edged razor sharp <> shape, and has a single 3/16" ID needle bearing at the prop end. Theory is it will slice through the water and have minimal driveline friction.
The offset rudder has dual H2O pickups, and will most likely be moved closer to the strut after testing.
Motor is a Leopard 5692 1090KV, and will be running 10S2P for testing. Have 730 & 1320 KV motors as alternates.
ESCs are Castle HYDRA ICE-2 200HVs.
More later..................
JIM
). And, is there that much of a performance between counter rotating props and twin lefties? I currently have CR sets of X465; X665; and X470, so I can go either way.
I hope all the races I won at 1/10 scale offroad trucks & buggies in the brushed motor days will help with my FE boat learning curve.
JIM
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