ZippKits JAE 45 Build Thread

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Thanks Mario for the pics and overview of your build. Couple of questions: Can you explain how you were able to modify the CMB pipe to telescope over the header. Also I see you angled the engine to eliminate the S bend in the stuffing tube that many people don't care for! Did you find this to be an improvement? Lastly can share some of the pipe length's you used to run the 2219/2319 props. Thanks Tim, Great post.
 
Thanks Mario for the pics and overview of your build. Couple of questions: Can you explain how you were able to modify the CMB pipe to telescope over the header. Also I see you angled the engine to eliminate the S bend in the stuffing tube that many people don't care for! Did you find this to be an improvement? Lastly can share some of the pipe length's you used to run the 2219/2319 props. Thanks Tim, Great post.
First, the tuned pipe trick: This was a neat little tip I picked up from Stu Barr himself. Get yourself a plumber's swaging tool from Amazon for around $21. This is what I use to expand the pipes, along with some heat from a torch. This process takes a while, generally around 45 minutes per pipe for me. However the results speak for themselves. I haven't ruptured a single coupler in the last 5 years I've been doing this.
20240327_002222.jpg

Second, the JAE 40 kit doesn't have drilled engine mount holes, so you're free to add or remove angle as you choose. Mount the motor parallel to the tub floor, you' ll need the S bend. Mount it at an angle to eliminate it. I chose to go with a 7° angle on the motor, giving me just one bend in the shaft. I went this route primarily so that could remove the stuffing tube from the hull if it needed to be serviced. I'm glad I did, I had to remove the tube after the boats first race last season when the rear ski split and needed a simple repair. As far as the performance, I personally don't notice a difference between the single bend in this boat and the S in my 20 version. But then again I'm still learning and my tuning skills are as refined as guys here who have built several times more boats than I have.
And third, I ran the boat with the same pipe length across the board from prop to prop.
This again has to do with my use of a telescoping style pipe/header set up.
In retrospect, I'm sure a small length change would have been beneficial when switching props but the boat seemed to do very well with both and a 9.25" pipe length
Hope this is helpful!
 
Thanks again Mario for the update. I'm sure many people are seeing the value of your posts and Buckshots JAE45 builds. The JAE has evolved into a competitive heat racing boat that many new boat modelers can afford. I have been fortunate enough to travel to many major NAMBA/IMPBA races around the country and I've seen JAEs at every one of them. Happy boating to all!!!
 
Day one, kit arrives. Laying out parts and taking inventory to understand what I have and where things go. Decided to power the boat with a CMB V5 45 and CMB pipe.
Opted not to change much on the kit as this is my first 40 boat build and I've given myself a deadline of 3 months to get the boat finished and ready to race.
View attachment 323491

Day 2, laminated both tub wall pieces together, established engine location with center 16" from transom, 7° angle, being sure to leave enough room for the belt to slip under the flywheel once boat is fired up. Also taking the time to use my shaft alignment tool to establish through hole locations for the bulkhead and radio box floor.
View attachment 323492
Mock up of tub walls in place, bulkheads, boom tube reinforcement, etc.
Decided to use StumpFab engine mounts. The grommets are wider than the tub walls, so I'm adding additional reinforcement on either side of the rails to account for this.
View attachment 323493

Also beginning to epoxy sponson side skins in place, using the aluminum pins as an alignment tool.
Hi Mario. On the engine placement that is 16" from center of the case to the back of the transom correct?
I was doing that same measurement on a 45 SGX tub just for the heck of it and the engine is 5 1/2"farther forward on the SGX. It's amazing how different the two design concepts are.
 
Hi Mario. On the engine placement that is 16" from center of the case to the back of the transom correct?
I was doing that same measurement on a 45 SGX tub just for the heck of it and the engine is 5 1/2"farther forward on the SGX. It's amazing how different the two design concepts are.
Correct, that's 16" from the motors casing center to the transom.
I always think it's fascinating how boats can have such different schools of thought in terms of design and still be equally competitive in the same arenas.
 
Correct, that's 16" from the motors casing center to the transom.
I always think it's fascinating how boats can have such different schools of thought in terms of design and still be equally competitive in the same arenas.
Yeah they are definitely different schools of thought when it comes to design. Thank you for the info. I appreciate it.
 
nice build. doc.
and c'mon cmb,, years back they where the only ones with telescoping sets for THIER engines. NOW i see why there are several people making billet headers
 

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