tturkey

What prop pitch lends itself to better to 3D flying.

One of my favorite airplanes is my Hog Bipe I built from a Sig kit. It has an OS 91 four cycle and a 14x6 prop. I've been flying it for 5 years now.

I've started to get real aggressive with it but I just can seem to get it to hover. I can hold a hover for a little but it has to be at full throttle. Any wind can blow it off and I just don'y have the power to pull out or correct.
I realize the control surfaces are not big but I thought a different prop might change the air flow and give me more control.

Should I change to a larger diameter and lower pitch or a smaller diameter with a higher pitch.

Any Hog Bipe fans out there.

I also have a new OS v95 four cycle but don't know if there is much power difference between the two.

daffydd

I would go up in diameter and down in pitch . try a different props , os 91 can spin a large range of sizes . try wood props ; carbon fiber . just experiment with a range

Bozarth

My Feedback: (15)

You are too far off for a change in the prop to make a difference. A good set-up will hover well below full throttle. The small percentage in increased thrust (if any) that a different prop might make won't get you there. You sound like you are ready for a true 3d airplane/engine combo.

Kurt

daffydd

You are quite right Bozarth . Start anew tturkey .there are many great 3 D planes available these days Keep the hog for hooning

tturkey

Thanks for the reply.
I do have a DA50cc Aeroworks Edge 540. But I get nervous and don't trust myself with 3D maneuvers. (A lot of money on that airplane!)
I have a many hours on the Hog and I'm vary comfortable with it.

daffydd

HI, tturkey. I understand your delema What about getting an electric 3D [Carbon yak 54 etc ,great fun only $ 500 dollars in OZ ] practtise . Get a Good 3 der to test and sort yourEdge,if possible . Start on low rates and move to full rates in steps . Remember it wont do all on lower rates , gets a feeling though . softly softly

Indiomike

My Feedback: (5)

I built a Sig Hog Bibe about 20 years ago. It was a great flying plane. You are way under powered with the OS 91 if you want to do a maneuver such as a hover. Full throttle just to barely hold the plane vertical is not adequate. You have to have enough power so that if necessary you can add throttle and fly upward out of the hover. In other words you have to have more thrust than the plane weighs. For example, if the plane weighs 7 pounds you need an engine that would give 10 pounds or more in thrust. If you are at full power just to hold the plane in a vertical attitude and you lose control, you have no option other than to fall off into a decent to gain flying speed. You try to hover too close to the ground and that happens, you will crash before you get enough flying speed to recover. I would want twice as much thrust as the plane weighs which in the example given would be an engine with about 14 pounds of thrust. Hovering requires a series of revving up the engine while in a vertical attitude so you have to have plenty of thrust to do that.

One thing that would help is to have a prop with low pitch. You would probably want a 15 x 5 over a 14 x 6. It's sort of like being in first gear in a car. You get maximum thrust but not much top end speed. Of course the prop must be within the working range for a given engine. The lower the pitch, the better for a 3D type maneuver. As you go down in pitch you usually have to compensate by going to a bigger diameter prop. In doing so, you have to consider that the larger diameter prop will give less ground clearance. That needs to be considered.

The Hog Bibe is a fine sport plane but not really designed for 3D maneuvers. Most 3D planes will have huge control surfaces compared to non 3D planes. With large control surfaces you need to keep overall speed down to lessen the problem of flutter. As you can see, there are are lot of things to consider and I've only touched on them without great detail. Enjoy the bibe for what it is and if you want to learn to fly 3D then get a plane designed for that purpose.

Mike