'A cubed' engine - Designed by Andy Brown

[Andy Brown]

What I was working on in 2005. The 'A Cubed' aka The "Potbelly" engine.

 

[ALLAN YUEN]

Look nice What size engine?

 

[RaceMechaniX]

Very cool Andy. Looks like SW modeling.

I take it you prefer the ramp style induction over the CAM style.

Tyler

 

[Toru Komatsu]

Hi Andy,

The groovings for scavenging ports in the crank case as well as the "Sonic Flow" exhaust system look very very nice!

Please make the engine real in .45 and .21 sizes! I will take them!!

Toru

 

[PAUL STIRTON]

Andy,

I like what I see there.

Talk to me on FB I may have something you will be interested in.

 

[Andy Brown]

Look nice What size engine?

Allan, The first was to be .21

Very cool Andy. Looks like SW modeling.

I take it you prefer the ramp style induction over the CAM style.

Tyler

Tyler, The "ramp" style has several advantages over the "CAM" style. #1. The ability to launch a rigger in bad conditions, even when the prop is too big. We put the "ski" on the Eagle SG to solve the launch issues we had with highly modified CAM and Picco drums systems. With the MAC engines, launch was never an issue without a "ski". #2 Lube and cooling to the Con-rod is MUCH better. I have seen many CAM con-rods turn blue and worse. I have never seen that happen to a MAC rod, and as you know that part of MAC and CMB are the same. Some people "claim" the power of the CAM/VAC drum system is more powerful. I have not found that to be true. It is true that the CMB VAC 91 has more power than the CMB HR 91 that used the "ramp" style drum, but the reason is that the HR91 drum system was far too restrictive. The HR91 drum bore was smaller than the drum bore of the MAC 67, plus the length and proportions were not correct. Concerning the details of the A3 drum system it may be noticed by some that it is similar to the "ramp" drum system that came out on the CMB 21 in 2007 and the 45 HR , 91 HR shortly after. Note that these drawing where made in 2005.

Also note: The drum housing and carb body are one piece and utilizes a composite snap on horn.

Hi Andy,

The groovings for scavenging ports in the crank case as well as the "Sonic Flow" exhaust system look very very nice!

Please make the engine real in .45 and .21 sizes! I will take them!!

Toru

Thanks for your comments and interest Toru.

Andy,

I like what I see there.

Talk to me on FB I may have something you will be interested in.

Thanks Paul! I'll talk with you soon.

 

[dwilfong]

Love the transfer shape...........

What about the short side profile of the ports?

Thick liner to make a good short side to match the out side profile?

Russian eng use this to make a good port cross section.

There is a new Gas eng in the design stages from Ukraine that is utilizing this also.

 

[Steven Bryant]

Looking good Andy,

 

[Andy Brown]

Love the transfer shape...........

What about the short side profile of the ports?

Thick liner to make a good short side to match the out side profile?

Russian eng use this to make a good port cross section.

There is a new Gas eng in the design stages from Ukraine that is utilizing this also.

Yes, the liner is thick David. There are two variants of the engine shown. The single image that is posted in colors was the Original and it had standard straight ports. The other three images are the final variant of the crankcase, but I did not post an image with the Piston/Liner porting details.

Looking good Andy,

Thanks Steven!

 

[ALLAN YUEN]

I wonder that when will you ready sell new A3 21engines?

 

[tnrcboatracer]

Andy, do you still have the CAD files for this design? Have you considered cutting the cases from billet stock?

 

[dwilfong]

With the 3D printers getting cheaper it seams every day and the materials thy can use better.

Can the case be made with one??????

 

[tnrcboatracer]

With the 3D printers getting cheaper it seams every day and the materials thy can use better.

Can the case be made with one??????

Sintered Ti alloy is what I'm thinking......

 

[dwilfong]

Ti case YA........now that would be the bomb..........................

Wonder how long it would take to print one........

Print one now that just mess with my mind.........................

 

[tnrcboatracer]

More like being buried in a sandbox....