K&B 4055 Engine Good for Stunt???

[frank mccune]

    Hi

    What is/was the scoop on the K&B 4055 as a Stunt engine?

                                                                     Tia,

                                                                      Frank

[Steve Helmick]

I had one in a Humongus and it wasn't adequate...and very heavy, even with a tongue muffler. I replaced it with a .46LA and the model flew much better. I'm not a fan, but it started ok and ran ok. Did I mention that it's VERY HEAVY?

FWIW, it makes no sense to me to have two bypass ports and a boost port in the cylinder, but only one big open bypass in the case casting that feeds all the ports.    Steve

[Randy Cuberly]

I used one in a Jamison and it worked very well in that airplane.  Burt Brokaw also has one in a Jamison that he regularly flies in OT Stunt and it works well also.

They are not a particularly powerful engines but run pretty smooth and a easy starters.  10-5 or 11-4 APC is a good prop for them.

15% Nitro, 22% half and half oil.

Randy Cuberly

[Steve Fitton]

Nice engine, although arguably outclassed by the LA-46.  When Brodak was selling the K&B 40 ABC there was no "out of the box" bolt in 40 size motor that didn't "need modification"  I really liked the way mine ran.  Yes, it is heavy, yes, the factory muffler was insanely heavy, and the tongue mufflers were very loud.  But it ran really well.  The demise of K&B and the arrival soon after of the LA 46 doomed the 4055 ABC 40 to the 700 or so units Brodak sold.

I still have one of the prototype 40 ABC K&B's on Mike Garmons Brodak P-51.  Its a sweet running setup.

[Steve Scott]

I ordered one from Brodak years ago but never mounted or ran it.  I sold it to a club member and saw it show up again this year at one of our swap meets.  I also had the ringed model 4011 K&B which I again never ran but sold it to another CL modeler in Ohio.  He wrote back to say it was one of the sweetest needling engines he's ever run.

[dennis lipsett]

Never having one of the Brodak offerings I was at first surprised at the remarks of low power. Realizing that it had been modified from the R/C engine cleared up that misinformation.
I had/have several of the R/C version and can relate an incident with one of them when they were first introduced. Bob Davis had made a head for the engine and asked me to see what it would do. This required a lot of prop runs and some flying. Had Bill Jamison do a flight and we tacked it with an 11/7 at 13,700. It was somewhat cool that day but the model was hauling a++ and sounded great. The protracted dive that he did was interesting when we heard a bang and then silence. Landing showed the top of the engine missing. Interestingly enough Bill Wisnewski did send me a new engine to replace the grenaded engine. As a glow they were not shy about revving either, but obviously not as much head pressure.
But the crux of the tale is that the R/C unit is not wimpy in any way and it's regrettable that it isn't useful in stock tune. Perhaps a side/rear pipe and a 11/3.75 3 blade might be the answer. But that's for someone else to play with.

Dennis

[Douglas Ames]

Nice engine, although arguably outclassed by the LA-46.  When Brodak was selling the K&B 40 ABC there was no "out of the box" bolt in 40 size motor that didn't "need modification"  I really liked the way mine ran.  Yes, it is heavy, yes, the factory muffler was insanely heavy, and the tongue mufflers were very loud.  But it ran really well.  The demise of K&B and the arrival soon after of the LA 46 doomed the 4055 ABC 40 to the 700 or so units Brodak sold.

I still have one of the prototype 40 ABC K&B's on Mike Garmons Brodak P-51.  Its a sweet running setup.

K&B is alive and well at MECOA in CA. http://www.mecoa.com/kb/aero/controlline.htm

[M Spencer]

   
K&B 4055 Engine Good for Stunt???

Theyd better be , Ive put one in my Macchi 72 !
Shaved the sides , outer head fin to same thickness as the rest , doesnt break through the bypass , a good 40 thou there after .
Leave a radius at the l.h. lug . left the ex stack about 2 mm out from the new fin line , to catch a muffler . Easier to tighten the mounting bolts now ,
and it looks trick .

will tryn throw a photo on , as it only takes a half hour now , if I talk to it loudly & clearly . 

might even weigh it , think it looses a good ounce .

according to something , the 40 rc abc & the CL are the same , bar intake .

Seen one fly in a typical P40 , stock entirely . 10 % nitro , wasnt totally hopeless . But thought mine'd better go better .


 Ive Chopped the can of the stack , horizontal cut . To modifly into a tounge muffler . Bigger than many commercial ones ,
so it should work. Out with the JB weld . Drilled one trough a 3/16 alloy plug and bunged in a few panel pins to secure .

[M Spencer]

heres a 1970 ringed ; Torpedo 40 test . The 71 got the twin piston bypass skirt ports .
other tests on a open exhaust had em peaking at 16.000 7 a 10 x 6 recomended .
the 71 40 in the MC 72 liked a 11 x 5 .
Accidently opened the needle from 1 7/8 turns to ONE turn , after dusk - with the dark red counter clockwise ' 90 mph ' stunter  .

long flight . Not over lean .

[M Spencer]

As theyre a development of the olde Wisnewski ' Torpedo ' racing engine , with bigger gudgeon , stronger rod , bigger crank , bearings & gas passage & increased ridgidity
and the transfers a copyish of the ST patented port used in the RATTLER ST / Torpedo 29 hybrid , there should be the potential to ' wake them up ', some .

A decent long tapered veturie intake might do a bit of good , steadying it up .

Ive left the bypass a shade wider than the fin , or havnt gotten around to getting it flush , yet ( may need less noseweight )  There sufficent meat in the side there.
but if I was waking it up ( 160 mph pylon ) might pay to leave it , at the K&B case Rattlers could blow the top off - due to the bypass being hogged out .

The Later the Torpedo , the bigger the bypass passage. Pretty much the same with ST too . Later cases having greater external bypass housing .
 Hence the chance to chop some off - inside or outside .

If theyre laxidasical , Id chuck on a 8 x 6 , wind it up / give it grief . After that if it didnt cooperate try 20 or b40 % nitro to see whatitd do , briefly .
20 % and the tourque should swing a 12 x 6 . As the ST 21 / 40 will on NO nitro - unmuffled . Sucks the juice with the effort though .

[M Spencer]

[M Spencer]

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[M Spencer]