Speedmaster 45 mono build with lots of questions

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Sean Bowf

Well-Known Member
Joined
Sep 6, 2007
Messages
716
Ok, here goes. I got a good deal on a speedmaster mono here, and am going to be putting it together over the winter...no plan to run it until next year.

My background has been mainly in racing RTRs over the last year. I have built and run a couple of A-riggers...but never raced them.

I have never played with a third channel on a boat...so that will be new to me too.

Some of the questions I have right now are...

1 - when the instructions on a boat give a CG for the boat, is that with the fuel tank full, or empty?? Or??

2 - Radio box...the hull pretty much just has the radio box floating between the rails. I take it that I will need to put something (blocks, crossmember...something...) that will hold the radio box away from the transom at least far enough for the pushrod seals and, of course, keep it from sliding forward. Is there any rule of thumb with this (distance, etc)?? Any other inputs on radio box placement/mounting? I have seen the inside of a seaducer, and saw that the box was held in by rubber bands...but did not really take note of anything else about how the box was mounted (thought it would be part of the hull).

3 - The hull instructions give a CG and a place for the engine. Would I be better off waiting until everything else is in the boat, and placing the engine in a spot that helps achieve the CG?? Or is the engine placement given in the direction important enough that I should mount it there and work everything else to try to achieve the CG?

4 - The instructions say to mount the engine with approximately a 7 degree angle. Ummm, Why?? If I can get the motor lower in the hull by having less of an angle, would that be good or bad?

5 - I am a long ways off from doing anything like a fuel tank, but the hull just has the 2 rails in it. If anyone has some input on which fuel tank to get, and how to mount it, I would love to hear it...

6 - Radio box...does anyone have an input as to the layout of the inside of the radio box?? Is there a standard for where to put which servo, and how to mount them that works best?? I was thinking of using some angled aluminum channel like I did in my last A-rigger...but am open to inputs from folks that have more experience. Any input on which pushrod seals to use?

7 - I plan to pick up a 3PM radio to use on the boat. Any input on which servos to use for rudder, throttle, and remote needle?

8 - Engine...I picked up (from here) a CMB .45 HR I plan on using in the hull. This is a far cry from any engine I have ever played with before (OS). There are no instructions with the engine. I don't plan on starting it until next year...but am interested in instructions on breakin and running the engine. There is a screw in the center of the carb control arm that has a bolt head. I didn't think there would be a mixture screw because the engine came with a remote needle. If this bolt headed screw is not a mixture screw, what is it?? If it is a mixture screw, does anyone have an input on where to set it (turns out, etc)?? There's another screw on the carb that looks like it has a locknut on it. Is this just a stop for the throttle, or something else?? The remote needle has a bolt headed screw in it. Any input on where to set this for breakin, and where I should be headed (ballpark) for running after breakin??

9 - Any inputs on which pipe I should be looking for with the above mentioned engine?? Pipe length?

10 - Part of the instructions say something like, "if trim tabs are used...blah blah blah." I thought pretty much every mono except the seaducer used trim tabs. Does anyone familiar with this hull have any input on this?

11 - I take it the rear of these hulls have something (aluminum plate?) in them to make the hull stronger for mounting the rudder and strut to the hull. Would this be correct?

12 - Hopper tank...is it important enough to figure out now?? Or can I just run the hull without it??

I am sure I will have 100 other questions as the assembly of this hull goes on. Thanks in advance for any inputs you have.

Sean
 
Last edited by a moderator:
Ok, here goes. I got a good deal on a speedmaster mono here, and am going to be putting it together over the winter...no plan to run it until next year.
My background has been mainly in racing RTRs over the last year. I have built and run a couple of A-riggers...but never raced them.

I have never played with a third channel on a boat...so that will be new to me too.

Some of the questions I have right now are...

1 - when the instructions on a boat give a CG for the boat, is that with the fuel tank full, or empty?? Or??

2 - Radio box...the hull pretty much just has the radio box floating between the rails. I take it that I will need to put something (blocks, crossmember...something...) that will hold the radio box away from the transom at least far enough for the pushrod seals and, of course, keep it from sliding forward. Is there any rule of thumb with this (distance, etc)?? Any other inputs on radio box placement/mounting? I have seen the inside of a seaducer, and saw that the box was held in by rubber bands...but did not really take note of anything else about how the box was mounted (thought it would be part of the hull).

3 - The hull instructions give a CG and a place for the engine. Would I be better off waiting until everything else is in the boat, and placing the engine in a spot that helps achieve the CG?? Or is the engine placement given in the direction important enough that I should mount it there and work everything else to try to achieve the CG?

4 - The instructions say to mount the engine with approximately a 7 degree angle. Ummm, Why?? If I can get the motor lower in the hull by having less of an angle, would that be good or bad?

5 - I am a long ways off from doing anything like a fuel tank, but the hull just has the 2 rails in it. If anyone has some input on which fuel tank to get, and how to mount it, I would love to hear it...

6 - Radio box...does anyone have an input as to the layout of the inside of the radio box?? Is there a standard for where to put which servo, and how to mount them that works best?? I was thinking of using some angled aluminum channel like I did in my last A-rigger...but am open to inputs from folks that have more experience. Any input on which pushrod seals to use?

7 - I plan to pick up a 3PM radio to use on the boat. Any input on which servos to use for rudder, throttle, and remote needle?

8 - Engine...I picked up (from here) a CMB .45 HR I plan on using in the hull. This is a far cry from any engine I have ever played with before (OS). There are no instructions with the engine. I don't plan on starting it until next year...but am interested in instructions on breakin and running the engine. There is a screw in the center of the carb control arm that has a bolt head. I didn't think there would be a mixture screw because the engine came with a remote needle. If this bolt headed screw is not a mixture screw, what is it?? If it is a mixture screw, does anyone have an input on where to set it (turns out, etc)?? There's another screw on the carb that looks like it has a locknut on it. Is this just a stop for the throttle, or something else?? The remote needle has a bolt headed screw in it. Any input on where to set this for breakin, and where I should be headed (ballpark) for running after breakin??

9 - Any inputs on which pipe I should be looking for with the above mentioned engine?? Pipe length?

10 - Part of the instructions say something like, "if trim tabs are used...blah blah blah." I thought pretty much every mono except the seaducer used trim tabs. Does anyone familiar with this hull have any input on this?

11 - I take it the rear of these hulls have something (aluminum plate?) in them to make the hull stronger for mounting the rudder and strut to the hull. Would this be correct?

12 - Hopper tank...is it important enough to figure out now?? Or can I just run the hull without it??

I am sure I will have 100 other questions as the assembly of this hull goes on. Thanks in advance for any inputs you have.

Sean
Sean can you take a pic of the bottom of the boat hull ? I would like to know what Speedmaster 40 hull you have. Also where are you Located? jw
 
Last edited by a moderator:
There is a picture of the bottom of the hull attached to this post.

I am in TX, but normally run up in the OK city area.

Sean
 
That is a really nice set up you've purchased..

I would follow the instructions EXACTLY as they to start. Put the engine where they say to and move the radio box and or fuel tank to get the CG just right. If that is a surface drive boat you can probably mount the engine horizontally. The issue would be the "s" bend in the shaft. But your bend would be so slight that it wouldn't hurt. Plus you would get the CG down even further. I would do it. Someone may know a reason not to though.

I would try it without trim tabs first. If you can get it to work without them it will probably be faster..

Hope this helps..

1 - when the instructions on a boat give a CG for the boat, is that with the fuel tank full, or empty?? Or??

2 - Radio box...the hull pretty much just has the radio box floating between the rails. I take it that I will need to put something (blocks, crossmember...something...) that will hold the radio box away from the transom at least far enough for the pushrod seals and, of course, keep it from sliding forward. Is there any rule of thumb with this (distance, etc)?? Any other inputs on radio box placement/mounting? I have seen the inside of a seaducer, and saw that the box was held in by rubber bands...but did not really take note of anything else about how the box was mounted (thought it would be part of the hull).

3 - The hull instructions give a CG and a place for the engine. Would I be better off waiting until everything else is in the boat, and placing the engine in a spot that helps achieve the CG?? Or is the engine placement given in the direction important enough that I should mount it there and work everything else to try to achieve the CG?

4 - The instructions say to mount the engine with approximately a 7 degree angle. Ummm, Why?? If I can get the motor lower in the hull by having less of an angle, would that be good or bad?

5 - I am a long ways off from doing anything like a fuel tank, but the hull just has the 2 rails in it. If anyone has some input on which fuel tank to get, and how to mount it, I would love to hear it...

6 - Radio box...does anyone have an input as to the layout of the inside of the radio box?? Is there a standard for where to put which servo, and how to mount them that works best?? I was thinking of using some angled aluminum channel like I did in my last A-rigger...but am open to inputs from folks that have more experience. Any input on which pushrod seals to use?

7 - I plan to pick up a 3PM radio to use on the boat. Any input on which servos to use for rudder, throttle, and remote needle?

8 - Engine...I picked up (from here) a CMB .45 HR I plan on using in the hull. This is a far cry from any engine I have ever played with before (OS). There are no instructions with the engine. I don't plan on starting it until next year...but am interested in instructions on breakin and running the engine. There is a screw in the center of the carb control arm that has a bolt head. I didn't think there would be a mixture screw because the engine came with a remote needle. If this bolt headed screw is not a mixture screw, what is it?? If it is a mixture screw, does anyone have an input on where to set it (turns out, etc)?? There's another screw on the carb that looks like it has a locknut on it. Is this just a stop for the throttle, or something else?? The remote needle has a bolt headed screw in it. Any input on where to set this for breakin, and where I should be headed (ballpark) for running after breakin??

9 - Any inputs on which pipe I should be looking for with the above mentioned engine?? Pipe length?

10 - Part of the instructions say something like, "if trim tabs are used...blah blah blah." I thought pretty much every mono except the seaducer used trim tabs. Does anyone familiar with this hull have any input on this?

11 - I take it the rear of these hulls have something (aluminum plate?) in them to make the hull stronger for mounting the rudder and strut to the hull. Would this be correct?

12 - Hopper tank...is it important enough to figure out now?? Or can I just run the hull without it??

I am sure I will have 100 other questions as the assembly of this hull goes on. Thanks in advance for any inputs you have.

Sean
 
There is a picture of the bottom of the hull attached to this post.
I am in TX, but normally run up in the OK city area.

Sean
Hello Sean,

What part of TX are you in? I'm in the Fort Worth/Arlington area. I would be more than happy to help you out. I'll be building a new mono soon as well.

I run that same motor in my SGX 40 hydro and it runs well. It will be interesting to see how it works in your mono.

Regards,

-Buck-
 
I can tell you from experience that you should use trim tabs and get them from David Prause because the ones listed in the instructions are too short. Also leave the rudder at it's full length. Follow the instructions for the rest.
 
I am in Wichita Falls Buck. I came down your way for one race this year (Carrolton). That is the only Race I did in TX though, most of what I have been doing is North (OK City, Wichita KS, Chanute KS). Been trying to work out a day to come down that way to do some testing and tuning with another guy down there (Clint), but just have not been able to get it worked out.

My thought on the engine...was that most folks are running surface drive on monos these days...so why not a hydro engine. That and the fact I got a decent deal from David on it...convinced me to try it...heh.

Sean

There is a picture of the bottom of the hull attached to this post.
I am in TX, but normally run up in the OK city area.

Sean
Hello Sean,

What part of TX are you in? I'm in the Fort Worth/Arlington area. I would be more than happy to help you out. I'll be building a new mono soon as well.

I run that same motor in my SGX 40 hydro and it runs well. It will be interesting to see how it works in your mono.

Regards,

-Buck-
 
I am in Wichita Falls Buck. I came down your way for one race this year (Carrolton). That is the only Race I did in TX though, most of what I have been doing is North (OK City, Wichita KS, Chanute KS). Been trying to work out a day to come down that way to do some testing and tuning with another guy down there (Clint), but just have not been able to get it worked out.
My thought on the engine...was that most folks are running surface drive on monos these days...so why not a hydro engine. That and the fact I got a decent deal from David on it...convinced me to try it...heh.

Sean

There is a picture of the bottom of the hull attached to this post.
I am in TX, but normally run up in the OK city area.

Sean
Hello Sean,

What part of TX are you in? I'm in the Fort Worth/Arlington area. I would be more than happy to help you out. I'll be building a new mono soon as well.

I run that same motor in my SGX 40 hydro and it runs well. It will be interesting to see how it works in your mono.

Regards,

-Buck-

Sean a hydro motor will work fine in this hull. The MAC I had in mine was built by Andy for a hydro and it ran well. The Speedmaster runs light on the water. Do not get caught up in the idea that what works on other monos will be fine on a Speedmaster because the setup is not the same. Not even close. This is order I would go about building the boat.

  1. Mount the strut per the boat instructions
  2. Mount the tabs from Dave Prause per Dave's instructions.
  3. Mount the turn fin per the boat instructions
  4. Mount the rudder per the boat instructions but do not cut it.
  5. Throw away the radio box that came with the boat & order one from Phil Thomas. The Speedmaster box has too small of a lip & will leak.
  6. Mount Phil's radio box with a 1 inch gap between it & the transom. I glue mine in with ShoGoo.
  7. Mount the servos with 3M trim tape.
  8. Mount the motor & pipe as low as possible making sure the boat balances at the recommended CG.
  9. Place a fuel tank on each side at the CG.
  10. Place the hopper tank in front of the motor.
  11. Block wet sand the bottom with 600 grit until it is flat & the edges are sharp.
Having the fuel at the CG means the boat will remain balanced as the fuel burns off. Putting it in front of the CG will compromise the boat's potential because it will be too tight at the beginning of the race and too loose at the end of the race.

The CMDI parabolic works well @ 10 inches with a 450/3. When the boat is setup correctly it will run flat
 
[*]Throw away the radio box that came with the boat & order one from Phil Thomas. The Speedmaster box has too small of a lip & will leak.
Joe, is this a radio box that is made for this hull? Or am I just looking for a radio box he carries that will fit?? Link??

Thanks for your inputs,

Sean
 
[*]Throw away the radio box that came with the boat & order one from Phil Thomas. The Speedmaster box has too small of a lip & will leak.
Joe, is this a radio box that is made for this hull? Or am I just looking for a radio box he carries that will fit?? Link??

Thanks for your inputs,

Sean
Phil makes a box thats fits the Speedmaster but I don't think it was made just for this boat. You can find him on this site.
 
[*]Place a fuel tank on each side at the CG.[*]Place the hopper tank in front of the motor.
Joe,

Do you use this setup with your 21? If so, which tank drains first? Any pics you'd be willing to share?

Thanks,

Rick
I don't have any photos & the only 21 Speedmaster I have built is my daughters which has the fuel in the front. When I build mine over the winter I will be using 2 Hayes 4 oz tanks on each side of the motor. Drain the right side first do the tank stays above the carb in the corners.
 
[*]Place a fuel tank on each side at the CG.[*]Place the hopper tank in front of the motor.
Joe,

Do you use this setup with your 21? If so, which tank drains first? Any pics you'd be willing to share?

Thanks,

Rick
I don't have any photos & the only 21 Speedmaster I have built is my daughters which has the fuel in the front. When I build mine over the winter I will be using 2 Hayes 4 oz tanks on each side of the motor. Drain the right side first do the tank stays above the carb in the corners.
Joe,

So you will not be using a 2 oz hopper in front of the motor?

R-
 
[*]Place a fuel tank on each side at the CG.[*]Place the hopper tank in front of the motor.
Joe,

Do you use this setup with your 21? If so, which tank drains first? Any pics you'd be willing to share?

Thanks,

Rick
I don't have any photos & the only 21 Speedmaster I have built is my daughters which has the fuel in the front. When I build mine over the winter I will be using 2 Hayes 4 oz tanks on each side of the motor. Drain the right side first do the tank stays above the carb in the corners.
Joe,

So you will not be using a 2 oz hopper in front of the motor?

R-
 
[*]Place a fuel tank on each side at the CG.[*]Place the hopper tank in front of the motor.
Joe,

Do you use this setup with your 21? If so, which tank drains first? Any pics you'd be willing to share?

Thanks,

Rick
I don't have any photos & the only 21 Speedmaster I have built is my daughters which has the fuel in the front. When I build mine over the winter I will be using 2 Hayes 4 oz tanks on each side of the motor. Drain the right side first do the tank stays above the carb in the corners.
Joe,

So you will not be using a 2 oz hopper in front of the motor?

R-

I haven't found that it is needed but I don't see any harm in adding one.
 
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