The "Hitchhiker's Guide" to the Maxi-Stream mod - Page 50

hahnmeister · 03/02/2006, 02:25 AM

Yeah, and not saltwater safe either.

ErikS · 03/02/2006, 09:16 AM

In reading through this thread I happened on interesting comments by jdieck on page 23 - explains why Tunze are shaped they way they are . Since I own a couple I have the luxury of seeing how they're built & comparing. I've read here that the prop needs some room to function effectively - in a Tunze the prop is some 1" (or more) away from the edges of the housing. Is this part of they key to flow? Would the maxi make even more flow with a larger housing?

I've also read a bit about props & performance. As many know ideal is max rpm w/ largest pitch (take a big bite as fast as possible). The pitch of the Tunze props appear to be less than the Dumas (just a guess). I guess they've maximized the speed VS bite of the prop (better to take less bite & achieve optimal RPM)....can we, the DIY'er accomplish the same thing? What would happen if we were to take a less pitch prop w/ the same size & spin it faster? (seems like everyone is looking for more pitch)

So far it's been an interesting experiment, it is an amazing little mod that has suprised me so far - thanks folks, I like playing with this type of stuff!

dhnguyen · 03/02/2006, 09:27 AM

Quote:

Originally posted by ErikS
In reading through this thread I happened on interesting comments by jdieck on page 23 - explains why Tunze are shaped they way they are . Since I own a couple I have the luxury of seeing how they're built & comparing. I've read here that the prop needs some room to function effectively - in a Tunze the prop is some 1" (or more) away from the edges of the housing. Is this part of they key to flow? Would the maxi make even more flow with a larger housing?

Yes. The challenge here lies in finding the proper material to make a larger housing and attaching it.

Quote:

I've also read a bit about props & performance. As many know ideal is max rpm w/ largest pitch (take a big bite as fast as possible). The pitch of the Tunze props appear to be less than the Dumas (just a guess). I guess they've maximized the speed VS bite of the prop (better to take less bite & achieve optimal RPM)....can we, the DIY'er accomplish the same thing? What would happen if we were to take a less pitch prop w/ the same size & spin it faster? (seems like everyone is looking for more pitch)

So far it's been an interesting experiment, it is an amazing little mod that has suprised me so far - thanks folks, I like playing with this type of stuff!

There is indeed a fine balance between propeller size and pitch for any given motor. too little pitch and your RPM will go way up causing excessive vibration, possibly to the point of damaging the motor as it was probably never designed to spin THAT fast. Too much pitch and RPM decreases as your motor runs out of horse power power.

It isn't all about picth it's also the size of the propelller and I've seen the Tunze's, their props are larger in diameter.

If you take a similar 1.25" propeller but with less pitch than a Dumas you will see that the flow is decreased. A simple comparison the 1,25" Nitro versus the 1.25" Dumas. Since the Nitro has slightly more aggressive pitch, it in turn produces more flow than the Dumas. While the 1.75" Dumas although has slightly less picth than the Nitro, it does have a larger diameter, hence produces better flow.

I guess that's why I'm still plugging at this trying to find a sweet spot.

ErikS · 03/02/2006, 09:35 AM

Quote:

I guess that's why I'm still plugging at this trying to find a sweet spot

Yep, I think the odds of Tunze letting us borrow their equipment for test is pretty low

I should have mentioned that the ones I have are the DC versions - might have less "torque" hence the lower pitch & faster RPM. I can say that they have done a LOT to make sure vibration isn't an issue. The tolerences are extrodinarily tight (the impeller to housing distance is almost nil). Seems like they kept pushing the RPM until no amount of engineering would allow it to function w/o virbration (& they do vibrate when spooling up).

Yep, the props are bigger.....but not massively so. I guess I was just suprised when I took the housing off & saw how small they were in comparison to the housing size.

Lots of props & so little time

Also, trying to carve that mounting plate back a few pages is no small task either - I don't have access to a CNC machine (without which as you mention limits the housing size).

ejmeier · 03/02/2006, 09:42 AM

Quote:

Originally posted by dhnguyen
Here are a couple DC powered pumps and can possibly be used.

http://www.dtekcustoms.com/index.asp...ROD&ProdID=138

http://www.dtekcustoms.com/index.asp...ROD&ProdID=172

Not exactly cheap though.

D.

Wait, are we talking about submerged application, or the above-tank mount? Those pumps are external only. That first one is actually made by Pan-World I believe, and it is just relabeled and sold to the PC cooling market. They have a DC line of pumps, which are quite pricey. Iwaki also makes comparable DC pumps, but they cost a LOT, and are mostly available to OEM applications, not really any retailers carry them. They give a good quantity discount if you buy them in the dozens, so it would be much better to buy from a retailer like the likes above.

That second one is actually made by Laing, (the same people who do the CSL/Posiedon 'titanium' series), and uses similar construction to the T1-4 line of pumps I believe.

http://www.lainginc.com/D_Series.htm

But contrary to the bigger ones, I have heard those little ones are quite noisy. (And I don't think they really use a shaft so to speak, so it would be very tough to redo the housing and get it stable w/o using a shaft. Look at the exploded view in the above link.

hahnmeister - what pump were you thinking of? A submersible DC pump? How could you use a DC adapter plug submerged? Can you describe it in more detail - never heard of a DC powerhead.

Ball · 03/02/2006, 09:56 AM

Quote:

Originally posted by dhnguyen
... I guess that's why I'm still plugging at this trying to find a sweet spot.

I have tried a lot of props. The one that seems to hit the sweetest spot in my testing, is this one.

http://www2.towerhobbies.com/cgi-bin...?&I=LXJ761&P=7

crypto · 03/02/2006, 10:17 AM

Quote:

Originally posted by dhnguyen
Hmmm Krylon Fusion will take care of that white epoxy

Sweet looking housing crypto. I see that you're reusing practicallyu all the SEIO parts

Yeah, it's also the last Seio I ever buy. but i do like their mounting brackets.

Quote:

Originally posted by zapata41
crypto, by using the outer housing as you did i think i can eliminate most all of the inner housing to allow the use of a bigger prop.

Tim

I use a 1.75" dumas that is cut down (that was a bit difficult). I used a hole saw on the housing and gutted it. I also took out as many of those slots as possible. The dumas is easily more powerful than the dual nitros but as I stated before, it wont start underwater. it's fine after once you drop it in though. perhaps the dumas is too much (maybe ok on an 820).

skierguy · 03/02/2006, 11:02 AM

As mentioned above, the Tunze has more space between the housing and the prop. Has anyone tried the 1.25Ã¢â‚¬Â props with the larger housing? If so, is there any difference in flow or reliability?

dhnguyen · 03/02/2006, 11:09 AM

Yes I have tried the 1.25" props with the larger housing. The flow although was improved wasn't significant enough to justify the design. You would need to use a larger propeller as well IMO.

D.

Aquaduck · 03/02/2006, 12:39 PM

I'm going to give this a shot. I picked up a propeller from a hobby shop (not very many props to choose from). It's a 42.5mm Graupner speed boat prop. with a pitch of 51 (whatever that means). # 2314.42,5. It has a M4 brass bushing that will need to be drilled out.

I was thinking about trying this on a MJ1200 with a 2" ABS pipe as a housing. Do you think the MJ1200 can handle this prop or do I need a smaller one? Second picture on this page. The prop on the left is the one I have. Graupner Boat Props

dhnguyen · 03/02/2006, 12:51 PM

42mm is approx. 1.70" I think you should be ok with a MJ1200. Nice 3 blade prop there. I'm most curious to see how much flow this can produce 3 blades versus the typical 2 bladed prop.

Keep us updated.

D.

Aquaduck · 03/02/2006, 12:54 PM

I'm using the 2 blade prop. This is it, a speed boat prop, the one on the left:

dhnguyen · 03/02/2006, 12:57 PM

Ah.. I see. Should be fine nonetheless as long as drill out the brass inserts.

Now I'm still cruious about the 3 bladed prop though. Hmmm...

D.

crypto · 03/02/2006, 12:58 PM

Quote:

Originally posted by Aquaduck

It has a M4 brass bushing that will need to be drilled out.

I forgot who posted this suggestion, but you might have better luck heating up the brass piece and pulling it out when it begins to melt the plastic.

dhnguyen · 03/02/2006, 12:59 PM

I tried that approach once. It didn't work as easily as stated. You're better off drilling it slowly and carefully.

D.

ErikS · 03/02/2006, 01:48 PM

Idea for mounting larger props -

DWV (drain, waste, vent) PVC fittings are bell shaped & you can get one in 3" -> 1.5". McMaster Carr part #2389K74.

Make the mount from 1.5" as usual,

Drill hole in a 3+" piece of acrylic & the OD of 1.5" sch 80 PVC is 1.9xxx" - a 2" holesaw should do just fine. A bit of #16 should hold it fine.

Fit to the back of the DWV fitting, flush trim for fit.

Would require a longer shaft to get the prop in the "big" part of the bell & most likely be a drilled vent setup.

This would allow us to turn a 2+" (if the maxi can do it) prop = more power.

zapata41 · 03/02/2006, 10:18 PM

i am gonna use a reducing coupling forthe guard on the seio, something like a 2x1 1/2 or maybe a 3x1 1/2, will look very similar to the tunze shroud that they use

Tim

mupham · 03/02/2006, 10:19 PM

I was using this 44mm (1.73") prop x 1.0 pitch I found at the Hobbytown USA near my house (it was all they had without the brass nut). It seems like my MJ has a real hard time getting it to spin under water. I tried to run it without the housing to see if it was just being restricted by the intake vents to no avail. Is it possible to take a bit off of the prop with the dremel and still keep it balanced? I may just go ahead and order the Nitro prop online after all.

It would also seem to me that a steeper pitch would cause the flow to spread out more since there is more edge pushing outward. I don't know if that is true or not, maybe someone can enlighten me.

Thanks,
Mike

dhnguyen · 03/02/2006, 11:30 PM

You might try shorten whole rigid tube/propeller assembly as bit and see if it would help.

I have no problems turning a 1.75" Dumas prop with the MJ1200 even a MJ900. How old is that MJ1200? Possibly the motor has worn out a bit and doesn't have as much horse power? Not sure...

D.

JohnL · 03/02/2006, 11:30 PM

This thread was automatically split due to performance issues. You can find the rest of the thread here: http://reefcentral.com/forums/showth...hreadid=790770

03/02/2006, 09:16 AM	#982
ErikS Registered Member Join Date: Nov 2001 Location: VA Posts: 2,199	In reading through this thread I happened on interesting comments by jdieck on page 23 - explains why Tunze are shaped they way they are . Since I own a couple I have the luxury of seeing how they're built & comparing. I've read here that the prop needs some room to function effectively - in a Tunze the prop is some 1" (or more) away from the edges of the housing. Is this part of they key to flow? Would the maxi make even more flow with a larger housing? I've also read a bit about props & performance. As many know ideal is max rpm w/ largest pitch (take a big bite as fast as possible). The pitch of the Tunze props appear to be less than the Dumas (just a guess). I guess they've maximized the speed VS bite of the prop (better to take less bite & achieve optimal RPM)....can we, the DIY'er accomplish the same thing? What would happen if we were to take a less pitch prop w/ the same size & spin it faster? (seems like everyone is looking for more pitch) So far it's been an interesting experiment, it is an amazing little mod that has suprised me so far - thanks folks, I like playing with this type of stuff! __________________ It's just my opinion & it's worth exactly what you paid for it

03/02/2006, 11:02 AM	#988
skierguy Registered Member Join Date: Jul 2003 Location: Nor Cal Posts: 194	As mentioned above, the Tunze has more space between the housing and the prop. Has anyone tried the 1.25Ã¢â‚¬Â props with the larger housing? If so, is there any difference in flow or reliability? __________________ That was one of my more spectacular Da Dunt Da Dunts… Aaron McGovern –Focused

03/02/2006, 01:48 PM	#996
ErikS Registered Member Join Date: Nov 2001 Location: VA Posts: 2,199	Idea for mounting larger props - DWV (drain, waste, vent) PVC fittings are bell shaped & you can get one in 3" -> 1.5". McMaster Carr part #2389K74. Make the mount from 1.5" as usual, Drill hole in a 3+" piece of acrylic & the OD of 1.5" sch 80 PVC is 1.9xxx" - a 2" holesaw should do just fine. A bit of #16 should hold it fine. Fit to the back of the DWV fitting, flush trim for fit. Would require a longer shaft to get the prop in the "big" part of the bell & most likely be a drilled vent setup. This would allow us to turn a 2+" (if the maxi can do it) prop = more power. __________________ It's just my opinion & it's worth exactly what you paid for it

03/02/2006, 02:25 AM	#981
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	Yeah, and not saltwater safe either.

03/02/2006, 11:09 AM	#989
dhnguyen Moved On Join Date: May 2004 Location: Kingston, WA Posts: 4,751	Yes I have tried the 1.25" props with the larger housing. The flow although was improved wasn't significant enough to justify the design. You would need to use a larger propeller as well IMO. D.

03/02/2006, 12:39 PM	#990
Aquaduck Registered Member Join Date: Mar 2004 Location: Waterloo, Ont. Canada Posts: 1,076	I'm going to give this a shot. I picked up a propeller from a hobby shop (not very many props to choose from). It's a 42.5mm Graupner speed boat prop. with a pitch of 51 (whatever that means). # 2314.42,5. It has a M4 brass bushing that will need to be drilled out. I was thinking about trying this on a MJ1200 with a 2" ABS pipe as a housing. Do you think the MJ1200 can handle this prop or do I need a smaller one? Second picture on this page. The prop on the left is the one I have. Graupner Boat Props

03/02/2006, 12:51 PM	#991
dhnguyen Moved On Join Date: May 2004 Location: Kingston, WA Posts: 4,751	42mm is approx. 1.70" I think you should be ok with a MJ1200. Nice 3 blade prop there. I'm most curious to see how much flow this can produce 3 blades versus the typical 2 bladed prop. Keep us updated. D.

03/02/2006, 12:54 PM	#992
Aquaduck Registered Member Join Date: Mar 2004 Location: Waterloo, Ont. Canada Posts: 1,076	I'm using the 2 blade prop. This is it, a speed boat prop, the one on the left:

03/02/2006, 12:57 PM	#993
dhnguyen Moved On Join Date: May 2004 Location: Kingston, WA Posts: 4,751	Ah.. I see. Should be fine nonetheless as long as drill out the brass inserts. Now I'm still cruious about the 3 bladed prop though. Hmmm... D.

03/02/2006, 12:59 PM	#995
dhnguyen Moved On Join Date: May 2004 Location: Kingston, WA Posts: 4,751	I tried that approach once. It didn't work as easily as stated. You're better off drilling it slowly and carefully. D.

03/02/2006, 10:18 PM	#997
zapata41 Moved On Join Date: Aug 2004 Location: Humboldt County, CA Posts: 2,024	i am gonna use a reducing coupling forthe guard on the seio, something like a 2x1 1/2 or maybe a 3x1 1/2, will look very similar to the tunze shroud that they use Tim

03/02/2006, 10:19 PM	#998
mupham Registered Member Join Date: Nov 2004 Location: West Chicago Posts: 31	I was using this 44mm (1.73") prop x 1.0 pitch I found at the Hobbytown USA near my house (it was all they had without the brass nut). It seems like my MJ has a real hard time getting it to spin under water. I tried to run it without the housing to see if it was just being restricted by the intake vents to no avail. Is it possible to take a bit off of the prop with the dremel and still keep it balanced? I may just go ahead and order the Nitro prop online after all. It would also seem to me that a steeper pitch would cause the flow to spread out more since there is more edge pushing outward. I don't know if that is true or not, maybe someone can enlighten me. Thanks, Mike

03/02/2006, 11:30 PM	#999
dhnguyen Moved On Join Date: May 2004 Location: Kingston, WA Posts: 4,751	You might try shorten whole rigid tube/propeller assembly as bit and see if it would help. I have no problems turning a 1.75" Dumas prop with the MJ1200 even a MJ900. How old is that MJ1200? Possibly the motor has worn out a bit and doesn't have as much horse power? Not sure... D.

03/02/2006, 11:30 PM	#1000
JohnL RC Staff Join Date: Oct 1999 Location: Long Island, NY Posts: 14,431	This thread was automatically split due to performance issues. You can find the rest of the thread here: http://reefcentral.com/forums/showth...hreadid=790770