How Proping Up Effects Motor/Esc Temps

[penz]

From my experience with land riggs gearing up will normally have more of an impact on motor temps than esc. I'm still new to boating and I'm guessing the same does not apply. With a 1.14x42 prop my esc is running around 120 on 4s with a 1900kv motor. I'm. Going to be throwing on a x442 prop and are concerned/curious how much the change in pitch will effect my esc temps. Of course the best way to find out is to just run it and see, but untill then any thoughts?

[Doby]

Increasing pitch and prop size generally will always put more load on your setup resulting in more heat.
Run a lap...bring boat in,,,check temps....repeat several times.

[penz]

Yeah that's what I figured. Is one lap enough to warm up the electronics enough? I would think like a few speed runs, and by that I mean 5 sec full throttle.

By the time I get the boat out the water and the tape off the hatch to check esc temp I would say close to a min has gone by. During that min would the esc be cooling off because its not in use? Or would the temp be higher due to residual heat and no water flow?

[siberianhusky]

those two props have the same pitch the number prop will have more lift that the x series prop. There shouldn't be much difference in load between the two, the difference would result in the hull running differently, depends on the boat setup.
If it's a tfl 1442 then it's an octura x442 copy. I've worked on a few tfl props now and really like them.

[AlanN]

If your boat already rides well and you want to change the prop, it is most important to raise the strut to offset the larger diameter and load. Most people don't want to adjust the strut becouse "the boat runs perfectly but I wanted more speed". When a larger diameter prop will want dig deeper and load up the motor more. Also, diameter and prop shape effect the handling of a hull. There's alot more to just putting on a bigger wheel.

[penz]

I believe it is a 1.14 pitch.. or basically 1.1. Its a turnigy aquaprop, hobbyking lists the pitch at 29...mm I believe, so 29/25.4=1.14. I could be wrong but if their specs are right then the x442 has more pitch.

Here the link.
http://www.hobbyking.com/hobbyking/s...x29x15mm..html

Oh and they are crappy props... only lasted 5 min then a blade sheared off...

[penz]

If your boat already rides well and you want to change the prop, it is most important to raise the strut to offset the larger diameter and load. Most people don't want to adjust the strut becouse "the boat runs perfectly but I wanted more speed". When a larger diameter prop will want dig deeper and load up the motor more. Also, diameter and prop shape effect the handling of a hull. There's alot more to just putting on a bigger wheel.

I think I got strut adjusted pretty well with the cheap plastic 42mm prop i had on there, im replacing it with a metal x442, so same od, but more pitch,

Good tip though

[siberianhusky]

you're right, I just never think people are using those props with a setup that has any power. There will be a huge difference between those two props. More than likely you will need to adjust the strut, the difference in lift characteristics between those two props will be massive! The boat will ride very different!

[znus]

Those Turnigy props are measured in a strange way, with half a rotation or one blade, or something like that. I believe Graupner does (or did) the same. Anyway, you need to double that 29 mm pitch to get a correct pitch reading, which makes it a 1.38 pitch prop (which makes more sense).

29 x 2 = 58 mm / 42 mm = 1.38

The pitch is realtive to the diametre. It's not inches (25.4 mm) or anything like that.

The Octura x442 will get up and go a whole lot better!! Plastic is for dialing in - then go metal.

[penz]

you're right, I just never think people are using those props with a setup that has any power. There will be a huge difference between those two props. More than likely you will need to adjust the strut, the difference in lift characteristics between those two props will be massive! The boat will ride very different!

Haha yeah... they were only a buck so I figured id give it a go and see how temps were to get a good idea of what metal prop to go with, and yeah I agree it will be a big difference with the x442 and some adjustments prob will be needed.

[penz]

Those Turnigy props are measured in a strange way, with half a rotation or one blade, or something like that. I believe Graupner does (or did) the same. Anyway, you need to double that 29 mm pitch to get a correct pitch reading, which makes it a 1.38 pitch prop (which makes more sense).

29 x 2 = 58 mm / 42 mm = 1.38

The pitch is realtive to the diametre. It's not inches (25.4 mm) or anything like that.

The Octura x442 will get up and go a whole lot better!! Plastic is for dialing in - then go metal.

Uhh... I'm not understanding. You saying the pitch divided by the od is....the pitch?...

Dividing 29/25.4 converts mm to inch. So a 29mm pitch prop is 1.14... if I double that its 2.28 and there no way it has that pitch...

[znus]

Uhh... I'm not understanding. You saying the pitch divided by the od is....the pitch?...

Dividing 29/25.4 converts mm to inch. So a 29mm pitch prop is 1.14... if I double that its 2.28 and there no way it has that pitch...

Oh man, did I open a can or worms here Sorry for my english, I'm swedish.

Anyway, the Turnigy pitch of 29 mm can not simply be transformed to inches, like the way you did. The 1.4 pitch on Octura propellers is not a measurement of inches. It's 1.4 times the OD.

An Octura x442 prop is 42 mm across and has 42 x 1.4 (pitch) = 58,8 mm thrust in one revolution. A x457 prop has 79,8 mm. Bigger prop, same pitch. It's a measurement of the angle/thrust of the blades in one revolution, not inches.

Turnigy specs their props with one blade = 29 mm. The prop has two blades (well, in your case - it hasn't anymore ) so, to get a reading comparable to Octura props, which specs their props with two blades, you need to double that 29 mm and get 58 mm.

With me so far?

So, we have a 42 mm OD blue plastic Turnigy prop with 29 mm x 2 = 58 mm of thrust. We divide thrust with the od (58 mm thrust /42 mm od) and get the "Octura way of pitch" = 1.38.

I hope you understand what I'm writning?

So, by going with a Octura X442 you'll get a better propeller but it will not make your boat go much faster. It'll accelerate better because of the bigger tounges and it might gain a few mph in top speed since the beryllium copper doesn't flex like plastic but it will not be a world of difference, since they both are more or less of the same pitch.


To make everything simpler - If Turnigy spec'ed their props the way Octura does, it would have 58 mm. (29 times 2)
/z

[penz]

OH WOW haha... well thanks for the explanation, I get what your sayin, this is still all new to me... It would be helpfull if turnigy would state that the pitch is only half of the full pitch... oh well.

Well my X442 is on the way so ill see how it runs with that, if temps are still good ill look at some 3 blade props.

[znus]

No problem man.

If temps are still good also try X640 (1.6 pitch), M445 and X445. Two bladed are usually faster! Not to mention easier to work with in terms of balancing and polishing (imho)

The X props are good all around props.
The M props are detounged. Doesn't hook like an X from the starting line but good for speed and nicer to your motor & esc.

[penz]

Cool thanks for the advise. So the x442 needs to be balanced? If so ill see if I can use some 3/16 tube I got on the way and throw it on my tire balancer. I'm guessing sand off where heavy?

[znus]

Cool thanks for the advise. So the x442 needs to be balanced? If so ill see if I can use some 3/16 tube I got on the way and throw it on my tire balancer. I'm guessing sand off where heavy?

yeah, almost all metal propellers need to be balanced. Octura castings are pretty decent compared to a few other companies but expect maybe one hour of work per prop. As you said - sand of the heavy until both sides are of equal weight. Only remove material from the side facing the transom (this cannot bbe stressed enough!)!! I use a dremel for this kind of work and when it's balanced I wet sand with fine paper (around 500) until i get a god shine. It doesn't have to have a mirror finish but it should be shiny

A magnetic balancer is 30 bucks. Eventually you'll need it anyway because FE boating is really fun and propellers are pure voodoo magic. That little sucker is gonna turn 30000 rpm and a little wobble or off balance can shake almost anything loose. I know it the hard way.

what motor have you got in your boat?

[penz]

I got a 3674 1900 kv motor running on 4s, runs pretty good, will run better with the new prop. I didnt realize I had to balance... crap... Just got the prop in the mail today, gonna see if i can construct my own magnetic balancer. Still waiting on the 3/16 brass tubing that I ordered from elsewhere because ose was out of stock and now they in stock haha!... figures...

[znus]

Just to make things more confusing - a 42 mm prop is about the maximum of what that motor should handle. For more speed I'd try going 5s and actuallt prop down to 39-40. Oh and one more tip, which may work for you or not, I've gotten great results with kyosho plastic props (around 40-42 mm). They look different from octura - almost boring but they really grip. It's like they dont know the words ventilate or cavitate. If you can find them give them a try!

im guessing you can find them as spare parts for kyosho boats?

[siberianhusky]

Sorry I'm with Penz on this one that is a 29mm pitch prop, Octura makes 12 series props which aren't far off 1.114, only one blade of an octura prop is measured as well, measure one blade through 180 degrees and multiply that by 2 to give the distance traveled in one rotation, less slip of course.
GrimRacer props are sold giving the diameter and pitch, no math required. I'm not sure how prather comes up with their numbering, doesn't relate to the diameter and pitch as far as I know.
Octura props are horrible from the factory! About the worst available! bad casting flash, very thick dull blades, way way out of balance, TFL props are better, GrimRacer props are pretty close for a factory job but you can do better even on your first attempt. Just sharpen the leading edge and smooth it all nicely, balance by removing material from the back side of the blade. The hard part is making sure it's balanced through 360 degrees, if the blades are level but the same tip is always pointing down that means that side is heavy! the prop should ideally stop at a completely random spot every time you spin it.
Make sure you use a good respirator and do all the work with the prop wet, berrylium is very dangerous to your health, don't use power tools, you'll never be able to clean all the dust up, I'll only use a file and sandpaper. If you doubt this do a quick search and verify it for yourself. Once it's in you it never leaves your body!

[penz]

Well temps will tell me how much my motor can handle, running the 42mm plastic prop my motor temp only got to 105. So I figured the x442 would have a little more pitch and be the next step up. If my temps still good and I want more speed ill prop up again. Sheesh didn't realize how much went into balancing/sharpening haha, guess I won't be on the water this weekend...

[siberianhusky]

Ya you will! Will be harder to make the balancer than to balance the prop!
One thing that makes it easier to work on the prop, find a screwdriver with a 3/16 shaft, put your drive dog and prop on this, makes a real nice handle for filing and sanding, you can just keep dipping it in water while you're working. Avoids cut fingers also.
I work over an old dish draining tray then rinse all the dust down the laundry sink.

[penz]

Thanks for the balancing tips! As far as making a balancer I got 3/16 steel stock at my work, going to machine the ends down to a point, then make the frame out of wood probably. Just need to find some good magnets

[znus]

Siberianhusky: the turnigy prop hasn't got 1:14 pitch. That was penz's division of 29 mm pitch into inches, which isn't the case. I have a handful of turnigy props (about 20....) and a handful of octura (about 30) and I can guarantee they're not that different. I think octura castings are pretty decent compared to abc. Thy look like a truck ran over them :.smile:

You're right abot the hazards of balancing with a dremel. I do it outside with a vacuum cleaner on full blast next to the prop.

/Z

[penz]

Well made my home made balancer, it works just fine!! 1/2 inch mdf, couple magnets and some 3/16 stock with the ends machined to points. Its not going to win any awards but it will do the trick.

IMG_20110714_164503.jpg

[penz]

Finally got the boat on the water. I adjusted the strut to be level with the bottom of the sponsons and threw on the x442 and wow what a difference! The boat is noticably faster, I can also hear that the motor is running at a higher rpm. I am very pleased so far. Only had time for a short run so hope to run more this weekend.