ISO Sensenich Q to try out

Airboat propeller discussion.
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OneBFC
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Re: ISO Sensenich Q to try out

Postby OneBFC » Thu Apr 11, 2019 9:56 pm

Makes sense a blade that can load the engine harder at a lower rpm will provide more thrust in that region. I would imagine that also came with some reduction in snap as well.

Life would be so much easier if we just had required power curves for all the props. It would make prop selection a breeze.

Coincidentally, same reason why I like props with wide tips vs narrow or taper tip. The wider tip provides more low rpm thrust and as long as your engine can keep up with the power, they really work better all around.
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SWAMPHUNTER45
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Re: ISO Sensenich Q to try out

Postby SWAMPHUNTER45 » Sun Apr 14, 2019 8:09 am

The Q blade works very well on a Cadillac they have the torque to turn them and the blade pairs well.

If you have a really strong 500 the old NGQ was even better.

Chuck is a very helpful member and knowledgable on everything from veterinary issues to structural load. If you got a question ask SlidinGator if he don't have the answer on the spot he will find it fairly quick. Can't say enough about how helpful he is to others. An ambassador for the sport.

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radtech
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Re: ISO Sensenich Q to try out

Postby radtech » Sun Apr 14, 2019 9:22 am

Swamp, that's the second time I've heard the reference to older verses newer Q blades. What is the difference between the two? I know Chuck's was an older Q. Would a newer one not be as good or vise versa? Should I be looking for an older Q to have redone or buy a new set?

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Slidin Gator
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Re: ISO Sensenich Q to try out

Postby Slidin Gator » Sun Apr 14, 2019 10:12 am

Radtech, the prop I run in the newer NGQ vs. the older Q that you tested. Based on what I saw during tuning, I think the older Q is a better match to your motor “as is” vs. the newer NGQ.

I say “as is” because during tuning the prop, it looked to me that your motor torque is climbing from 2400-3000 and makes peak torque above 3000 rpm. I believe we started at #3 pitch and that choked it down to 2,400. We went to #2 and it jumped to 2800. That is a lot of change vs. the 200 rpm drop (2,800 to 2,600) that the same settings do on my setup. We then took a bit more pitch out to settle at 2,900+. Now I am running a 72” diameter and you are at 74”, so that is part of the difference for sure, but the motor sure seemed to be sensitive in that range to me.

The NGQ is a wider blade than the Q and needs good torque over the 2-3k range. As is, the NGQ would make planning more difficult for you, the Q likes RPM and is a good match. For the same reasons, a Whisper tip would also be a good match as they like to turn.

On the other hand, if you were to follow Swamp’s suggestions and go see Mr. Branch for a better cam and a properly dialed in carb (the one I loaned you was still on the lean side for that Caddy) your motor would probably wake right up and would be a great candidate for the NGQ.

Of course, if you are going gear box in the future, this all changes.
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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kwanjangnihm
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Re: ISO Sensenich Q to try out

Postby kwanjangnihm » Sun Apr 14, 2019 10:14 am

Tony480 wrote:I have run both the Q4 (no I beam),and now the Q6 (with the I beam).You can tell a little difference between the two. But if you find a good deal on a Q4 buy it, there is not a whole lot of difference.


DAGWOOD0520 wrote:Some times a little bit is a lot for some boats and we are trying to get every last lb of thrust out of these props as possible so when we started doing the i-beam in blades we thought that it wouldn't be right if we didn't put it in all of the blades. The only reason it never made it in the H series is because of the airfoil shape and we had already started the N design.
" I don't care who you are back in the world, you give away our position one more time, I'll bleed ya, real quiet. Leave ya here. Got that? "

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Slidin Gator
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Re: ISO Sensenich Q to try out

Postby Slidin Gator » Sun Apr 14, 2019 10:27 am

Thanks Kwan, good reminder, they still make the Q, listed at $685 per blade. Mine is the older Q4. Dropped it off last week for a refurb.
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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radtech
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Re: ISO Sensenich Q to try out

Postby radtech » Sun Apr 14, 2019 3:03 pm

That's what I was wondering about. I wonder, is it that much of a difference, and I should first see if I can locate a set of Q4 blades or just buy a set of new ones. Thanks for the info!

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Slidin Gator
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Re: ISO Sensenich Q to try out

Postby Slidin Gator » Mon Apr 15, 2019 12:44 am

radtech wrote:That's what I was wondering about. I wonder, is it that much of a difference, and I should first see if I can locate a set of Q4 blades or just buy a set of new ones. Thanks for the info!

The Q4 blades put a smile on your face, so they would be an upgrade. But realize that any Q4 blades are old, they would have to be damn cheap for me to buy them and plan to pay for a refurb. When I dropped those Q4 blades off for refurb last week they pointed out some cracks around the shank. It may just be sun damage on the outside or it might be time to retire them, they have to inspect them on the inside to determine. One would have to be a late night radiation tech to fully inspect a set before purchase :wink:

Dagwood's post put it into perspective for me, the internal I-beam construction makes a big difference on blade stiffness. With every revolution the air loading on the blade changes as it goes by the oil cooler, transom, radiator etc. As the load changes the blade flexes which fatigues the blade over time and creates vibration issues, all of which basically converts engine power to heat (blade and air). Heat, blade and engine damage is all useless for making the boat go, we don't need that :violent1:

A used set may work, but $1,400 for a spanky new set is where the house money goes. Just make a midweek, overnight run down to drop the boat off with Mr. Branch and order the new blades. Then come down for 2-3 days to pick everything up and we can go riddin so I can take video of the ear to ear grin. :cheers:
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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radtech
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Re: ISO Sensenich Q to try out

Postby radtech » Mon Apr 15, 2019 2:25 am

Lol I hear ya, brother! Gonna be a minute before I can afford to shell out that kinda money, though. We'll get it right before too long. Got the new carb in Sat morning. Gonna try to get it put on this week if I can scrape up the time. Got a tile job to do starting Wednesday when I get off work. I'm hoping to finish by Thursday evening so I can get the carb on friday. I'm beginning to save up for a set of blades and a new hull. The hull may have to wait til next year, though...we'll see

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dodobird
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Re: ISO Sensenich Q to try out

Postby dodobird » Mon Apr 15, 2019 8:27 am

Got a 1.66 to 1 beltbox for sale $1400 obo and u can still use ur 74" prop used a 74" powershift on this box n it moved a 14x8 alumitec on ground good that was with a sbc this box is a older box it's a ch3 has the big cog tooth belt ....imo I dont think any prop u put n that boat is gonna make it run ground I'd take the prop u have now cut it down to 70 or 72 n and get more pitch unless u got a medium hub n u can go with a short ...pitch pays the bill's

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Re: ISO Sensenich Q to try out

Postby lilly-Pad » Mon Apr 15, 2019 11:05 am

I am with Chuck on this one Tim. get some regular Q blades and come down to see Mr. Branch so he can help U harness that caddy to it's fullest and we will get to ride some more :cheers: :cheers:
12 ft Don Davis / 0470 conv / 68 NGQ , A.A.O.F member

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Re: ISO Sensenich Q to try out

Postby radtech » Mon Apr 15, 2019 6:29 pm

I like the sound of that, but I don't know if I could afford him. Lol


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