I have a sig astro hog with an O.S. 70 surpass 4-stroke engine on it. Any prop "size" recomendations for it?

please reply soon,

big dan

Dan,

I would go with an APC 12X6 to start with and once it's broken in a 13X5, also APC

What he said!!!

Ken

Suggested Prop(s): Sport & Stunt models: 11x8,11x9,12x7,12x8,12.5x6
Scale models: 13.8x8,14x7,15x6,16x6
3-Blade: 11x7

How in the world am "I" supposed to know what to use on it? I never used a 4-stroke before. They should have about 30 more choices so I could just Flip a Coin!

Thanks for your advise Bubba. You sure have some nice planes I see in your dossier!

big dan

bigdanusa,
It is hard to find the right prop sometimes. A lot of times the right prop on one plane isn't any good on another plane. The recommended props in the engine manual are a good starting place, and then you should experiment with different props to see which prop fits your plane and your flying style.

Ken

Thanks Ken.

I just don't wanna ruin my new 4-stroke but yet I want enough prop to get me off the grassy runway for my maiden flight.

big dan

Thanks Dan,

The Aerotech Yak is no more, not wrecked, just a POS so it no longer flies. It is being replaced with a Aerworks 50cc Extra 260 and the one that is not there is the Great PLanes Cap232 160 on a DA50

Bubba,

Here is my current POS's fleet.

I'm half ashamed to let anyone see em!

Falcon lll with over 500 flights, Goldberg Cub, and my Astro Hog.

I have a 70 Surpass 1 on my Astro Hog. I use a 13x6 Master Airscrew K series (the ones with white tips, supposedly 'four stroke' props). It flew great with this prop until a few weeks ago. The elevator fluttered (we think) and the horizontal stabilizer departed. It rolled inverted and glided a long way before it crashed. The repairs will take a long time.

I've seen your astro hog several times. Sorry about your loss Carrellh.

I used your recomendation to begin with so I have 3 of those props. Just wondering what others would use for my 4-stroke on my astro hog.

Thanks,

big dan

Yours looks really good. These are super flying planes. They originally flew with engines under .40 size but were built lighter than the SIG version. The Hog was the first (or close to it) successful low wing pattern plane. One of the veterans in our club told me that they would go high and dive to build up speed, do a maneuver, then go up and do the same thing for the next one. They couldn't depend on power to drag them around so the models were designed to fly "on the wing."

You're going to be surprised how little ground speed you need before the plane wants to fly. That's why it doesn't need super prop. The design of the plane simply makes it want to fly.

IMHO
(OS70 4 stroke) + (13x6 prop) = (perfect balance of thrust / speed / engine RPM)

OS lists a huge range of props for all of their engines and between my brother and myself we have bought them all.
To bad we wasted so much money.

61 4 stroke = 12x6
70 4 stroke = 13x6
91 4 stroke = 14x6

I am not a speed freak so these are the only sizes I will ever for these engines in the future.