K&B Only Class - Pipe Testing

Discussion in 'General RC Boating Forum' started by BobBonahoom, Oct 9, 2019.

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  1. Oct 9, 2019 #1

    BobBonahoom

    BobBonahoom

    BobBonahoom

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    We have added a K&B 3.5 only racing class in the Twin Cities. Any hull type is allowed, but it must use a K&B 3.5 engine. In my case I put my 3.5 K&B into an old JAE G2 hull. It weighs 4 lbs. and uses a 45 Zipp strut with ball bearings. So far the best prop has been a 1715-17-45. Today I tested some pipes to see which was the best with it. Speeds are peak speeds as determined with an onboard Futaba telemetry system (GPS).

    NovaRossi 21 pipe at 8-1/4" to the weld - 45 mph.
    CMB 21 pipe at 8-1/4' to the weld - 53 mph.
    Bouchie 21 pipe at 8-1/4" to the rearmost weld on the converging tail cone - 54 mph.
    Zipp Kits new 21 pipe (same dimensions as the Bouchie pipe) at 8-1/4" to the rearmost weld on the converging tail cone - 56 mph.

    So the winner is the new Zipp pipe. The water was choppy so I think 60 would be possible on flat water. The new Zipp pipe is really nice looking too. It is aluminum but polished to a mirror finish.
     

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    JRXHydros likes this.
  2. Oct 9, 2019 #2

    bob miller

    bob miller

    bob miller

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    how many people are in the 21 k/b group ? sure wish new k/b p/s were being produced
     
  3. Oct 9, 2019 #3

    BobBonahoom

    BobBonahoom

    BobBonahoom

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    We have 4 or 5 people running it here. It's just a local thing we did for fun.
     
  4. Oct 10, 2019 #4

    Geraghty

    Geraghty

    Geraghty

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    Send your P&S to this guy.....for $15.00 + shipping your piston liner will come back better than new and it lasts just like a new P&S..... This guy knows what he is doing...

    http://www.osrocketracing.com/
     
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  5. Oct 10, 2019 #5

    mike walker

    mike walker

    mike walker

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    I am very happy with the Zipp pipe.
    I also think what you guys are doing is awesome. Just wish I wasn't so far away. I have a K&B in a rigger by the (neb) That's necked eye ball don't think I hit 50 with it maybe 45 and couldn't turn any of the abc 17s Great job!
     
  6. Oct 10, 2019 #6

    brad nichols

    brad nichols

    brad nichols

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    I have a few 21's and 45's + 1 or 2 67's

    Brad
     
  7. Oct 10, 2019 #7

    Grimracer

    Grimracer

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    I was going through my motor collection last night and found two new K+B 21s in the box I did not know I had.. LOL.. Cripes.. i have too much crap!

    LOL

    Grim
     
  8. Oct 10, 2019 #8

    Geraghty

    Geraghty

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    This class was an experiment to see if we could offer something that didn't need $1000 3.5 boats to compete....Our course probably has 250' straightaways and 50' corners ....it is a little bull ring.....
    I bought [2] NIB K&B 3.5's off Ebay for less than $100 each....That coupled with a $100.00 boat and you have a competitive fun class to run.....Any boat with any K&B 3.5 is allowed to run....On the small course if you get the start , drive a good course....someone will really have to work to get around you....
    Nearly everybody in this hobby started with a K&B outboard 3.5 and has it lying in a box somewhere ...get it out and put it on a JAE outboard 21 for $89.00 and hit the start and you will have a blast....racin' is racin' whether you are running 50 or 70 mph....
     
  9. Oct 10, 2019 #9

    John Beardslee

    John Beardslee

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    Rod when I started it was either a K & B 40 series 70 pylon air plane engine with a cool clamp or a Super Tiger G21-40 with a cool clamp. Very little activity in those days with 19 or 20 size, maybe Veco. In the big blocks 60 size was the largest available no 90’s back then. When talking to K&B( John Brodbeck) at that time of producing a purpose built marine engine his comment was “why should I spend all that money when I can sell pylon motors to airplane guys and they’re perfectly happy with them and I can’t keep up with the orders as it is. Times changed for the better and I’m sure your influence and the rest of the west coast model boating community contributed greatly to that change.
     
  10. Oct 10, 2019 #10

    shoboat

    shoboat

    shoboat

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    Rod, Bob, & John,

    I wished I lived across the lake in Wisconsin sometimes, it would
    be fun to play with the older stuff again.
    Would it be legal to put the K&B-21 in a Zipp Kits 12-GT? Maybe I could
    take the ferry over to Mondovi, Wisconsin next summer? John may even
    like to come join us? Sounds like a good time.

    Let Me Know Please?

    Mark Sholund
     
  11. Oct 10, 2019 #11

    John Beardslee

    John Beardslee

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    Yes sir!!! Possibility of snow there for sure! I don’t think Rod can control the weather yet. Haha!
     
  12. Oct 10, 2019 #12

    John Beardslee

    John Beardslee

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    We road the ferry many times when I was racing big boats toNeosha, Kenosha and many other race sites in Wisconsin.?Lots of boat racing hustings Wisconsin!
     
  13. Oct 11, 2019 #13

    Marty Slater

    Marty Slater

    Marty Slater

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    how about outboards any of them
     
  14. Oct 11, 2019 #14

    BobBonahoom

    BobBonahoom

    BobBonahoom

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    We set the rules as follows (to keep it simple):
    1. Any K&B 3.5 engine built with K&B parts and carbs. Inboard or outboard.
    2. Any engine mods as long as you use the K&B 3.5 parts.
    3. Any pipe, but no 1/4 wave short pipes from back in the day. Anybody remember them? They were a ~6" open tube and incredibly loud!
    4. Any hull type, tunnel, rigger, mono, cat, etc.
    5. Any fuel, prop, etc.
     
  15. Oct 11, 2019 #15

    BobBonahoom

    BobBonahoom

    BobBonahoom

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    I took the ferry to Michigan for a race two years ago. Works great, but it takes a lot of time. Sure beats driving around Chicago though. The pond we are racing on is a small one in Chippewa Falls (near Eau Claire) . Its similar to the Badger's pond, so we run a small course.

    Put you K&B in ANY hull. 12 GT is fine. By the way, I tried that once with the a 3 port 21 Nova in one of the shorter 12 JAE hulls and the boat was insane. It was not controllable at all. Maybe it would work in the longer GT?
     
  16. Oct 11, 2019 #16

    Geraghty

    Geraghty

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    As long as it is a K&B based 3.5 whatever....put it in or on whatever you want and build it and bring it.....
    Running on our little bull ring of a course is a great equalizer....
    Starting and driving will be the main determining factors to the competitors success....and you can race without killing your Visa card....
    A 3.5 K&B outboard on a Zippkits .21 outboard JAE.....That would be a killer combo.....
     
  17. Oct 21, 2019 at 9:25 PM #17

    XtremeRcBoats

    XtremeRcBoats

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    Hi BoB, had a look at the Zipkits pipe at the website and it looks real nice. Do you know if they are planning also the bigger size Bouchie pipes?
     
  18. Oct 21, 2019 at 10:03 PM #18

    Geraghty

    Geraghty

    Geraghty

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    More new Zippkits pipes?????.....Nothing in the works as of now.....
     

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