Rear Exhaust Gas engines

[Gilbert Pun]

I use square drive to almost all of my gas boats with a flex cable saver just to stop the cable from slipping to the end.

 

[Gilbert Pun]

These are the RE engines I currently have on hand,

1, RCMK K30 about to change to WYK33 Carb. and an alum. pulley to replace the pull start.

2. Quickdraw 27 RE

3. J & G 29 RE

Appreciate any comments and any special attention I have to note for running these engines.

 

[Gilbert Pun]

 

[lohring]

My bet is still on the Quickdraw for best performance. The Quickdraw hot pipe is great for over rev and has a broad power band. It should work on all the engines with a custom adapter for the header. The long flex adapter is probably OK for gas scale boats, but we always ran a lot shorter section in the high rpm engines. The engine should have a wide, flat area of peak power. That makes prop matching and setup easier. See the below data from their early engine development. The difference was the transition to an early version of the hot pipe. Your engine should have similar characteristics but with more power. The dyno data is on the Quickdraw web site.

Lohring Miller

 

[Gilbert Pun]

Hi lohring,

Very good info, thanks

Gilbert

 

[Tom Foley]

Nice hijack Steve and the wrong forum to boot.

 

[Wesleys Custom Graphics]

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I use square drive to almost all of my gas boats with a flex cable saver just to stop the cable from slipping to the end.

 

[Wesleys Custom Graphics]

So is there anything different on the strut end?

 

[Stuart Barr]

So is there anything different on the strut end?

Wes,

Call me and I will explain better.

Stu

 

[Gilbert Pun]

I use one piece flexcable so the saver is required to stop it from slipping out on the strut side.

 

[John Seybold]

Gil,

What's the advantage of using that cable over a traditional one that locks in the collet????

Thanks

 

[John Seybold]

Double post

 

[Jay Stone]

I am looking to maybe put a cmb in a new 6 scale. Stu thinks it would be a good match and I trust his judgment. He also recommends a square drive setup. That's the only thing that has me concerned. I'm not too familiar with that kind of setup.

Have you considered a Solid Flex Drive from Brent Byers? I am going to use one on my next thunderboat build and likely my 1/6 scale when I can figure out which hull I plan to build.

http://jrcbd.com/forum/showthread.php?6912-For-Sale-Solid-Flex-Drive-(SFD)&highlight=Solid+flex

 

[Jimwhyte]

I just built a 1/6 scale 77 Atlas Van Lines "Blue Blaster" with the rear exhaust RCMK 29.5 and it's awesome. I just need a stainless header the aluminium one snapped right in half at the serrations.

 

[Hydro Junkie]

Gil,

What's the advantage of using that cable over a traditional one that locks in the collet????

Thanks

I know, this post is a year and a half old, but it is a good question. I figure it deserves an answer so, here it is. A square drive, if used with a ferrule in front of the strut to hold a stub shaft, will prevent you from ever loosing a prop and stubshaft if the cable breaks. Also, you don't have to leave as big of space between the drive dog and strut since the engine end floats in the collet rather than being clamped there. This lets the cable "shrink" from the front rather than the rear

 

[brad nichols]

It also does not put a thrust load on the engine's front bearing.

Brad

 

[Hydro Junkie]

Very true, which means it's possible that you may get a few more RPM out of the set up. I use this set up in my scale Elam and it does work well. The only thing to remember is that a thrust washer is needed to prevent wear on the drive dog and strut

 

[Gilbert Pun]

Gil,

What's the advantage of using that cable over a traditional one that locks in the collet????

Thanks

I know, this post is a year and a half old, but it is a good question. I figure it deserves an answer so, here it is. A square drive, if used with a ferrule in front of the strut to hold a stub shaft, will prevent you from ever loosing a prop and stubshaft if the cable breaks. Also, you don't have to leave as big of space between the drive dog and strut since the engine end floats in the collet rather than being clamped there. This lets the cable "shrink" from the front rather than the rear

Thanks, mark, you have answered that for me that is what it exactly meant, the shaft would have more play while running to move front and aft. I have missed this one.

 

[Gilbert Pun]

Like to know if anybody here has tried the CMB 27 Evo rear exhaust engine to compare with the RCMK and Quickdraw engines ?

 

[Hydro Junkie]

I've heard there are some building boats with it, I'm working on a boat that will get one as well as it's only got a scale 4.5" wide engine bay aso everything else is too wide