Hybrid Rotary Cutter Proof of Concept

[dieselscout80]

Ok, looked up Woods C114-1: 3 spindle, CW conventional rotation, staggered spindles.

From videos I see on YT, the LH tire track hits the left spindle at about 10:00-11:00.... that's the forward sweep on this CW blade. Anytime a tire track aligns with forward sweep it spells trouble!

So, what to do... sharp blades, WOT (wide open throttle), slower ground speed, lower HOC, and most effective: shift mower left to put tire track 12:00 or more on LH spindle (BACK SWEEP IT!). Hopefully won't screw up RH spindle cut.

A ring baffle may help... exactly like radiator fans: close to the blade helps (3/8- 1/2" radially) and just into the wing region axially. In Experimental, I'd have the guys weld more wing on a blade too (welder needs to KNOW what they're doing! Pre-heat 5150 etc). Wing: 30 deg for better lift / 45 deg wings = less lift and THROWS grass further. Welcome to the club!

Thanks

I’m going to need a bit of translation.

What does these mean:
1. “just into the wing region axially” mean?

2. “pre-heat 5150”

 

[dadohead]

1. Axially: in the direction of the fan axis. Bring the height of the rings just into the blade wing height to create maximum lift... more is not better (leaves more blade exposed for cutting too). Note the ring heights on my initial post.
2. Most blades are made of either 10B38 or 5150 steel and hardened to the HRC 38 range. They are difficult to weld safely. Many won't do it. I've had several blades welded by expert welders. They preheated the parts before welding. Not for amateurs like me!

 

[dadohead]

Since you worked for JD, is there a reason for not having more, or at least SOME, choices in pull-type mowers for smaller tractors?

Cost. Pull-type mowers require at least 2 rear wheels and external hydraulics to operate the lift. Since their driveshafts operate in 3d space, expensive CV joints must replace the cheaper cardan joints found in 3pt mounted mower driveshafts.

 

[Little Red Tractor]

That is an exceptionally well-done project. You certainly put all your acquired skills to work on it and it came out great.

I'll guess that most of us share your frustrations with single spindle cutters. They just don't give good cut quality unless you do a LOT of overlapping. Great, great job.

 

[Runner]

2. Most blades are made of either 10B38 or 5150 steel and hardened to the HRC 38 range. They are difficult to weld safely. Many won't do it. I've had several blades welded by expert welders. They preheated the parts before welding. Not for amateurs like me!

I was wondering about the blades on your cutter which seem to have high-lift ears welded onto them. Did you experiment with different heights/shapes of "ears", and did you do the welding on them?

 

[dieselscout80]

Woods makes three types of blades for the C114 straight, twisted and high fin. I have the high fin (lift) blades.

I have thought about adding more to the fin to increase lift.

Would you recommend adding the baffle first or increasing the blade fin/wing?

 

[dadohead]

I was wondering about the blades on your cutter which seem to have high-lift ears welded onto them. Did you experiment with different heights/shapes of "ears", and did you do the welding on them?

Yes, I had wings welded on. The stock Fred Cain 3' blades I started with were very low lift... just a small 'tip up' for a wing. Initial testing proved the concept very quickly as the tire tracks were back-swept nicely. The forward-sweep region (usually the weakest part of the cut) was pretty bad. As I mentioned before, the front blade was handing off all of its discharge to the rear and completely disturbing the cut as well.

Ring baffles came first. They separated the chambers and got the material flowing efficiently. The rings also add lift. The cut improved but the forward-sweep was still weak (right side of each blade on my CCW mower). The guy I used at Deere is now retired but still welded the wings onto my blades. The cut improved significantly.... a forward-sweep stripe is still present though.

After living with the mower though, there was NO CHANCE of ever going back to the single spindle... I wanted best cutting/safest blade for the long run. I contacted Haven Steel, maker of the Fred Caiin blades (and every other swing blade made) and had them make new blades. They are sized like the Fred Cain blade with a wing profile following our best JD blade... that's what I'm currently running.

In taller grass, a forward-sweep stripe is still there. It is a "hump" shape, not the ragged/uncut stripe my Frontier would produce if you cut full width. It is acceptable to me though. This is 20" cut to 4":

I'm finding that the job goes so much faster now that I'm mowing more often. The look improves as well.

 

[dadohead]

Would you recommend adding the baffle first or increasing the blade fin/wing?

Woods knows what they're doing. With 3 lifts already available, I would assume their high lift would be as good as you could get. I wouldn't weld on them.

First thing I would try is to shift the mower left to put the tire track to the back-sweep of the blade. The mower tongue is probably adjustable to shift the mower position. That would be VERY effective. If not, fab a ring baffle and tack it to the LH chamber. Be mindful of how your mower discharges though: side discharge? Rear? The baffle must allow somewhere for the material to discharge. Hope this helps!

 

[BnRidge]

I wanted best cutting/safest blade for the long run. I contacted Haven Steel, maker of the Fred Caiin blades (and every other swing blade made) and had them make new blades. They are sized like the Fred Cain blade with a wing profile following our best JD blade... that's what I'm currently running.

Every deck seems to require a different type of blade. I worked for a blade manufacturer. There were a couple of tests we did that simulated running across a stake, like a surveyor stake, or a fence post in the case of a forage harvester, yet the blades afterward needed to still function, and without breaking. There were instances of broken blades - one was on I94 near the Milwaukee veterans cemetery, where they were mowing the lots. A broken blade went across the highway and through the windshield of a car. I was going to say welding on them sounds like a quick r&d thing to get it done, but then you went out and had some made.

 

[D&D]

Yes, I had wings welded on. The stock Fred Cain 3' blades I started with were very low lift... just a small 'tip up' for a wing. Initial testing proved the concept very quickly as the tire tracks were back-swept nicely. The forward-sweep region (usually the weakest part of the cut) was pretty bad. As I mentioned before, the front blade was handing off all of its discharge to the rear and completely disturbing the cut as well.

Ring baffles came first. They separated the chambers and got the material flowing efficiently. The rings also add lift. The cut improved but the forward-sweep was still weak (right side of each blade on my CCW mower). The guy I used at Deere is now retired but still welded the wings onto my blades. The cut improved significantly.... a forward-sweep stripe is still present though.

After living with the mower though, there was NO CHANCE of ever going back to the single spindle... I wanted best cutting/safest blade for the long run. I contacted Haven Steel, maker of the Fred Caiin blades (and every other swing blade made) and had them make new blades. They are sized like the Fred Cain blade with a wing profile following our best JD blade... that's what I'm currently running.

In taller grass, a forward-sweep stripe is still there. It is a "hump" shape, not the ragged/uncut stripe my Frontier would produce if you cut full width. It is acceptable to me though. This is 20" cut to 4":

View attachment 3752433

I'm finding that the job goes so much faster now that I'm mowing more often. The look improves as well.

Ok, I'm convinced. Please ship my free demo unit (in Kioti Orange) with account funding for fuel and wear parts. We will provide future evaluation and testing of performance on a variety of east coast lawn and pasture grasses.