Capt. Bill

Most of the 40 size planes from the 70s and 80s show a K&B 40 on the plans and I flew several with one. Now I use a 46 FX or AX. Does anyone have the horsepower and other ratings for the K&B 40.

rcdude7

My Feedback: (264)

I have a couple K&B .40 engines and without a doubt, they are way down on power compared to a .46 fx/ax.

The K&B .61 6550 would be a much closer match powerwise.

Capt. Bill

I still have my K&B 40 but don't have the manual anymore. I have heard that todays 46 size engines are equal to the older 60 size engines.

fb

Paperwork I have for the K&B 40 I have #4011....cubic in. 6.44 ..........bore .840.....stroke .720.......displ. .399............wt. 13.5 oz

huck1199

Is yours a 4011 with ball bearings? If so it has pretty good power. If it is a bushed or plain bearing the power is less. I did have some spec sheets but can't find them at the moment.

Capt. Bill

I think it has ball bearings. I bought it back around 1972 since that is when I got my first 40 size plane. It says Torpedo 40 on the side and has a Perry carb, think it came with it but not sure.

NM2K

My Feedback: (14)

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Everyone keeps saying that, but I haven't found it to be true as yet. The older engines (of equal displacement) are closer to the modern engines than most folks would think, when both are running stock, non resonant mufflers and largish stock propellers (11x6 to 11x8). Especially when you factor in the extra girth and weight of the modern 10cc engines. Like the financial commercial says, sort of, "It isn't how much you make - it's how much you keep". Sometimes, the lighter weight and smaller footprint of the old baffle piston engines evens out the increased horsepower of the larger and heavier schneurle ported modern 10cc engines. At least it does for me.

Wanna see that K&B .40 rock and roll? Fit it with a 9x6 prop on a sleek airframe.


Ed Cregger

CoosBayLumber

My Feedback: (1)

As I remember, a few of the now obsolete names on magazines did tests on the K&B series, when new. They always reported upon the H.P. output, versus PRM range.


Wm.

djlyon

Wrong there Ed - 8/8 rev up

Denis

turbo.gst

My Feedback: (8)

I used to fly a K&B .40 with Perry Pump and Carb. It was very lite weight and had great power. I used it like a .45 My only complaint was noise. It was very Loud. It handled very well having a great idle, instant transition and good top end.

turbo

stg61abc

Hi, please look at the link below, the K&B 40 is still produced by MECOA...
here you´ll find the tec. specification on all K&B engines
the 4011 (.40) is rated at 1.0 HP

http://www.mecoa.com/kb/aero/aircraft.htm

hope that this will help you

Capt. Bill

Thanks for the info. I got the K&B 40 for a Southern R/C Bobcat, a 40 size version of the pattern Tiger Tail plane. Mine didn't have the Perry pump but did have a Perry carb. Could you beat those carbs back then? It had baffle plate instead of a muffler but I got an add on muffler that strapped on and had plugs for the holes in the exhaust where the baffle was. It it been over 30 years but I remember the Bobcat was pretty fast with the K&B. I still have some of the props I used since I can't use them on my OS engines because of the larger hub, I still have 10X6 and 11x7 Top Flite wood props. Ball bearings instead of sleeves, ABC and Schnuerle porting each have meant an increase in engine power. Of course some people think that twice the power will make the plane go twice as fast but forget that drag is the limiting factor

Jim Thomerson

The only direct comparison I have made is on and Old Time Stunt CL airplane. Same prop and fuel, the K&B 4011 is noticably more powerful than a Tower 40. There may have been a slight difference in venturi diameter. If so not much, but the K&B was more fuel hungary. The K&B set for a stunt run turns an 11 x 5 APC at 9,700 on Sig Champion 10% nitro 20% 50/50 oil fuel.