Chilli
03-10-2011, 10:34 PM
You don't see too many Record Trials builds but I'm going to break tradition and share this build. I had allot of fun with my Spec "limited" JAE this past year. And I wanted to take it up a notch with a IMPBA P-hydro Oval Records build. I was motivated by the performance and lap times the nitro record holders (mainly Kentley Porter and Martin Truex) have been getting out of their JAE's in 2 lap ovals. I've been RC boating 2 years now with nine builds under my belt and have always played it safe by copying other peoples set up. This will be the first time I venture on my own. Hopefully I have learned enough from the good people on this board to be successful. My goal with this boat is to break the IMPBA 2 Lap oval record. My only expectation is to have fun and learn as much as I can from the guys in my district. Some of which are among the most knowledgeable people in the hobby.
The JAE FE is a great boat but the standard 2.5" interior width was just not going to cut it for my purposes. So I asked Mike Luszcz to laser cut me some pieces to widen the tub to 3". That extra 1/2 inch makes quite a difference. Using a combo of 2S and 4S packs I can now easily fit a 4s2P or 6s configuration in the tub. The extra beam also makes it a breeze to fit a Castle 15xx series motor with water jacket. I also toyed with moving the rear bulkhead up a bit but decided to leave the rest of the kit stock.
The tub was constructed using the Zippkits JAE FE kit as well as the modified pieces done by Mike. I reinforced the transom inside and out with 1/16" CF Plate. I also reinforce the sides where the motor mounts with 1/16" G10 Fiberglass. One mistake I learned is that when gluing the G10 to the tub walls I should put the plywood/G10 sandwich on a flat table with a weight on them to keep them from warping while curing. I had only clamped everything together after gluing and ended up with tub walls that were slightly warped. Despite a trace amount of warping (only at the motor mount area) , the bottom of the boat is square and I'm hoping it will not affect the performance of the boat. For hardware, I went with a Speedmaster small strut (with the nose cut down) and the Speedmaster mini rudder. I wanted an adjustable strut in this boat and a rudder that is a little longer. The Speedmaster rudder is 1/4” longer than the Zippkits. On my spec boat I ran the rudder 1-5/8” below the ski and the boat slides a bit in the turns. On this boat I’m at 2”. The rudder mount is too big for the transom so I cut half of it off using two screws to mount. I added a strip of CF plate to tie the tub wall to the rudder mount keeping the rudder aligned. On the tub lid, I added a little lip catch on the front to keep the front of the lid pinned down. It seems no matter how well I tape the cover on my JAE, the front of it lifts up a bit. I don’t want that bad boy peeling off at 70+.
One the inside, I used a two piece Williams Racing 3” rail mount and asked the good people at South River RC trim 1/16” off each end to allow for the G10 reinforcement. To accommodate the motor, I had to move the point at which the stuffing tube exits the tub rearward an inch or two. Because of this, I ran out of room for the servo on the floor of the tub. So I took some marine plywood and built a perch to raise the servo over the stuffing tube. This ended up being a good thing because the servo arm swings down to the perfect height through the transom to the rudder arm. The rudder servo is a HS-5245MG which is Hitec’s most powerful mini. The motor being uesed is a Neu 1521/1D (2900). This is a vey hot SAW motor. No three minute runs with this boat! Hopefully I can keep her cool and happy with smaller props. Keep in mind that total run time shouldn't be more than 45 seconds. Speed controller will be the new Castle Hydra Ice 240. For props I’ll be starting with a ABC 1716 . The motor should be able to take much more prop but I’m not sure I can. :eek: Batteries will be 4S1P Thunderpower 65C Lipos with 8mm bullets.
The sponsons are standard JAE. The only mod I made was for the turn fin mount. Some use the supplied wood screws and some use threaded inserts but I have had problems with stripping so I ended up installing blind nuts recessed in the wooden dowels. After assembly, I drilled out the dowels all the way through for #6 hex machine screws with my crappy drill press. Then on the outside of the sponson, I drilled 3/8” holes 1/2” deep into the dowels, sealed with epoxy, installed the #6 blind nuts and filled the holes with 3/8” dowel. One inch stainless hex screws now hold the turn fin solidly. David Preusse will be doing a replacement fin for my boat taking into account the additional weight of a FE over a nitro version.
That it folks. Hopefully I can get some test time within the next few weeks!!!
The JAE FE is a great boat but the standard 2.5" interior width was just not going to cut it for my purposes. So I asked Mike Luszcz to laser cut me some pieces to widen the tub to 3". That extra 1/2 inch makes quite a difference. Using a combo of 2S and 4S packs I can now easily fit a 4s2P or 6s configuration in the tub. The extra beam also makes it a breeze to fit a Castle 15xx series motor with water jacket. I also toyed with moving the rear bulkhead up a bit but decided to leave the rest of the kit stock.
The tub was constructed using the Zippkits JAE FE kit as well as the modified pieces done by Mike. I reinforced the transom inside and out with 1/16" CF Plate. I also reinforce the sides where the motor mounts with 1/16" G10 Fiberglass. One mistake I learned is that when gluing the G10 to the tub walls I should put the plywood/G10 sandwich on a flat table with a weight on them to keep them from warping while curing. I had only clamped everything together after gluing and ended up with tub walls that were slightly warped. Despite a trace amount of warping (only at the motor mount area) , the bottom of the boat is square and I'm hoping it will not affect the performance of the boat. For hardware, I went with a Speedmaster small strut (with the nose cut down) and the Speedmaster mini rudder. I wanted an adjustable strut in this boat and a rudder that is a little longer. The Speedmaster rudder is 1/4” longer than the Zippkits. On my spec boat I ran the rudder 1-5/8” below the ski and the boat slides a bit in the turns. On this boat I’m at 2”. The rudder mount is too big for the transom so I cut half of it off using two screws to mount. I added a strip of CF plate to tie the tub wall to the rudder mount keeping the rudder aligned. On the tub lid, I added a little lip catch on the front to keep the front of the lid pinned down. It seems no matter how well I tape the cover on my JAE, the front of it lifts up a bit. I don’t want that bad boy peeling off at 70+.
One the inside, I used a two piece Williams Racing 3” rail mount and asked the good people at South River RC trim 1/16” off each end to allow for the G10 reinforcement. To accommodate the motor, I had to move the point at which the stuffing tube exits the tub rearward an inch or two. Because of this, I ran out of room for the servo on the floor of the tub. So I took some marine plywood and built a perch to raise the servo over the stuffing tube. This ended up being a good thing because the servo arm swings down to the perfect height through the transom to the rudder arm. The rudder servo is a HS-5245MG which is Hitec’s most powerful mini. The motor being uesed is a Neu 1521/1D (2900). This is a vey hot SAW motor. No three minute runs with this boat! Hopefully I can keep her cool and happy with smaller props. Keep in mind that total run time shouldn't be more than 45 seconds. Speed controller will be the new Castle Hydra Ice 240. For props I’ll be starting with a ABC 1716 . The motor should be able to take much more prop but I’m not sure I can. :eek: Batteries will be 4S1P Thunderpower 65C Lipos with 8mm bullets.
The sponsons are standard JAE. The only mod I made was for the turn fin mount. Some use the supplied wood screws and some use threaded inserts but I have had problems with stripping so I ended up installing blind nuts recessed in the wooden dowels. After assembly, I drilled out the dowels all the way through for #6 hex machine screws with my crappy drill press. Then on the outside of the sponson, I drilled 3/8” holes 1/2” deep into the dowels, sealed with epoxy, installed the #6 blind nuts and filled the holes with 3/8” dowel. One inch stainless hex screws now hold the turn fin solidly. David Preusse will be doing a replacement fin for my boat taking into account the additional weight of a FE over a nitro version.
That it folks. Hopefully I can get some test time within the next few weeks!!!