rye

My Feedback: (10)

hi
i have a goldberg chipmunk and a os-61 with a pitt's muffler what prop should i use ,thanks

jeffie8696

Iwould use an 11X7 to start with however all props are not created equal, what brands are you considering?

cymaz

Or a 12x6

snir2001

My Feedback: (1)

12X6 for the combo of 61 and goldberg chipmunk

cymaz

Don't forget to fly it scale like not like a 3D machine. It looks nicer and fellow pilots will appreciate that.

landeck

My Feedback: (1)

I use APC 12x7 on OS .61 SF and FX engines. I have the SF engines currently in a Super SkyBolt and a Trojan T-28 and the FX in a Pulse XT. It works very well on all three planes. In my experience an 11x7 will under prop those engines. An 11x8 is another a good choice.

Bruce

Hossfly

You have had a number of GOOD choices presented to you. I have not flown a Goldberg Chipmunk, but have flown a number of such airplanes and similiar power plants.

I suggest you start with the proverbial 12-6 WOOD prop. Preferably a rather wide blade such as Master Airscrew. Once you get a good flier on that then experiment.

What do you want to do with the airplane? (1.) Whiz by the crowd? Try a 11-7.5, 11-7, 11-8, maybe a 10/10.5-9. You can try the curved leading edge types. (2.) Nice aerobatics and /or scale-like flying? I suggest you try a 12-5,6, 11.5-7. Don't pass up trimming props a bit. Square tips can be made curved or swept back or your desires. Just be sure to balance well.
Then if SPEED is your goal use the 11-8 and maybe even clip the ends a tad.
Some folks believe the prop is for the engine. My long time racing pylon made me believe that each flight is a different trip and only experimentation will find the right prop-airplane combination for any given set-up. Diffeent airframes determine the actual best prop for any given engine, in that airframe.

Landings are easier with longer length and less pitch. You can also adjust ailerons to a little up for washout if needed. I am not familiar with the Goldberg but back in the early '70s I had a SIG Chipmunk with HP .61. It was prone to tip stall without washout. Many guys had that problem and same with the Sig Mustang which had the same wing form.

Models are different than the real machine. I was given the opportunity to fly the REAL 1:1 scale Chipmunk that Sig modeled after. While the model flew very well after a tad of washout, the real machine was simply a NICE airplane. OTOH being a jet-driver, that little machine taught me one thing for sure and that was if I pursued that kind of flying I had a whole LOT to LEARN. [:@]

Best of luck to you and your chipmunk. Don't acept anything as an absolute and have a ball with however you wish to perform.