stunthanger.com
Engine basics => Engine set up tips => Topic started by: Willis Swindell on April 01, 2007, 08:37:23 PM
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After buying my ARC Strega, Steve Fitton let me borrow his Brodak K&B 61 ABC engine to use. I had originally had some imput with Mike Garmon on the production of this engine. Bill Wisniewski sent us a Gold Twist head 61 to convert to control line stunt . This was in the winter and Mike wanted to use Fox Super Fuel that way any fuel would work. The engine would not run very good it would just stop in some embarrassing places. The engine was running too cold. Talking to Bill we explained that the twist head was too cold and needed to make the fins smaller. Bill said that they still made the old K&B 61 He put the abc liners in the old case . That was the cure the engine ran great The only change we made was a .312 venturi, that size was the best of all the ones we tried. Brodak ordered I think 300 of these ABC 61 Then K&B promptly went out of business.
I put Steve’s K&B in my Strega and It ran just like I remembered great ! With a 13 x 5 Zinger and a 6 oz tank at 9,000 rpm at sea level it ran only 6 min. I had to go too 6 1/2 oz tank. the engine is great in a Strega.
Then at our local hobby shop I found a K&B 61 ABC twist head for 99 dollars retail. and also that the engine was still being manufactured. some say you can get it in a control line version. I bought the RC version and made a venturi and had a light muffler laying around that fit, the K&B muffler weighs 3.9 oz. Found a OS SF 40 needle valve that fit. The venturi base is about 3/4 inch wide. I figured with some 50 50 fuel the engine would not cool off as much as 29 % castor in Fox fuel.
I flew the gold head 61 today and it ran as good as the Brodak K&B 61. For 99 dollars you can’t beat it. The 50 50 fuel worked like a champ.
Willis y1 ;D
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Willis,
Very interesting. What does the Gold Twist Head weigh all set up for C/L not including the muffler?
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Crist,
I think Russ Gifford used a 'gold head' variant prior to running a PA61. As I recall, Russ liked the run characteristics.
Fred
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Hi Crist
The engine with a control line venturi weighs 13.7 oz
Willis
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Willis,
Thanks. That's why I asked because Russ spoke highly of them.
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Crist
The engine comes with a fit so tight at top of the stroke you can hardly turn it over and makes it a bear to start the first time, it has a good taper. After the first run it feels fine. A Veco type tank needs a 1/ 16 inch shim under it.
Willis
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I have a few more flights on the K&B now The tank needs to be on the barriers with the engine and it can do the pattern with 6 oz of fuel. using 10 22 50-50 Power master fuel 13x5 Zinger at 9,000 RPM turns 5.4 sec. on 68 ft lines on the rich side in level flight. The electric starter can now turn the engine over, before the first run it could not turn the engine. and don’t hardly prime it before starting it doesn’t take much.
Willis y1
I hate to say this but the Strega weighs 74 oz.
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That twist-head K&B is really something. My opinion on watching Willis fly both engines is that the twist head motor is way stronger and even better running than the earlier style Brodak/K&B 61. The motors sound completely different as well. The twist head sounds like a PA-65 on a pipe, whereas the original style has the standard ST-60 sound to it. I took a snapshot of the Strega in question being launched earlier today:
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I checked Mecoa's web site and under Promo's they have this engine for 99.99 + S&H. I also checked and that page was last updated 3/07 so it's current. It is the R/C version. It's under Modeler Dirrect.
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Willis Swindell, and John Tate (and the late Mike Garmon) know their engines! All them had a part in that "Brodak" K&B 61 Stunt, I understand. If Willis says it works well, it does........... believe me!
Bill <><
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For this engine then the venturi of choice is the 312 ? and the OS SF 40 NVA ?
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Ok guys,
you have me totally confused (Not too difficult!). n~
Which of the K&B .61's is the one to use for CLPA???
Thanks,
Jim
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The Twist head (Gold) K&B 61 is the one I believe they are refering to.
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Read carefully above. They both work well. The stock K&B 61 with the proper size venturi is a good substitute for an ST 60, at the cost of an extra ounce of weight. The twist head 61 has more power and more of a pipe -style run.
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Sorry I haven't checked this post lately. The ABC K&B 61 both the twist head and the Brodak stock style ABC 61 both have the two four style of run. I have no experience with the stock style 61 with a ring that they still make.
The Brodak style 61 you can't buy anymore.
Willis
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Willis Swindell
"I hate to say this but the Strega weighs 74 oz."
The Strega is a Patternmaster, and that is the planes flying weight; the low to mid seventies. That is also the reason for the big wing-lift. Big Jim did not design the Patternmaster\Strega to fly at Nobler weight.
Big Jim flew his Patternmasters with his "Big Jim Hemi" ST 61, which puts out serious horsepower. If you've got the ponies, the Strega\Patternmaster will fly.
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Proparc
A few years ago I held Al Reed’s Patternmaster with a Greenway ST 60. I have never held any plane that pulled that hard on the ground. I remember thinking this plane is going to fly at 100 mph, There will be no way that he will be able to stunt this plane. Boy was I wrong, after that flight I knew what was ment by “stunt run”. If the plane was anything but the Patternmasater I would have bin right about the speed.
Willis y1
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Willis: In using the NVA for the SF on the Gold head, since the spray bar is narrower than the holes (which are threaded) what was your process for sealing the outside of the engine case ? Thanks
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Leester
The needle from the FS 40 is almost the same as a ST I think .153 It was a close fit as as I remember I didn’t even drill out the threads in the engine. The SF 46 is another animal it is a lot smaller .140 . The K&B is .159, ST is .156
Willis