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Prop for a Delta Force 33 PLEASE

Prop for a Delta Force 33 PLEASE

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Old 06-01-2016, 11:48 AM
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Default Prop for a Delta Force 33 PLEASE

I bought a used boat, and within a few runs, the shaft snapped and I lost the beautiful, sharpened, stainless prop.



Id like to replace it with the same, but I dont know what it was.

3/16" shaft

4S power

2400kv Leopard motor.

Any help would be MUCH appreciated.

At this point im about ready to go diving for it to see if I can find it.
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Old 06-02-2016, 11:48 PM
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Talk to Steve at Offshoreelectrics.com

He will sort you out. Looks like it was an Aluminium prop?
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Old 06-08-2016, 12:20 PM
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J G has props of all sizes. go to a local rc shop and buy two or three and test them out. make sure you leave room for it to grow and use a good thrust washer set up, NOT A BUSHING, oil it each time it goes in the water and grease on the shaft every time, I use pro long grease for the last 40 yrs of racing. I wish I were at home I could send you a few props to test.
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Old 06-30-2016, 08:21 AM
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I did end up finding out what the prop was from the previous owner

http://www.offshoreelectrics.com/pro...od=cnc-4214250

It works quite well, but not being sharpened definitely shows a ~3mph loss in top end

BUT, the sharpened prop cavitated a lot, and this new unsharpened one never cavitates, though I do now get chinewalk.

Oh well.

I do grease the shaft every few runs with waterproof axle grease, and I do have a good thrust washer.

I acutally think I could og with more prop, as the motor and esc are ice cold.
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Old 07-01-2016, 11:47 AM
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What is the purpose of the Thrust bearing if the boat uses a flex shaft? There should be about a 1/4 inch gap between the drive dog and strut. If there is the drive dog will never touch the strut. If it does touch the flex shaft will be unduly stressed every time as it constricts under load. The electric motor bearings can take the axial load and the thrust bearings are not designed for much more that 15,000 rpm. It is only robbing rpm (speed). Its something u'd see more commonly in a gas boat with a square drive and flex ferule set up. I would remove it and set a proper clearance gap. There is a way to prevent prop loss in the event of a break. The prop is 7075 magnesium/aluminum alloy not stainless.

Last edited by AMB; 07-01-2016 at 12:04 PM.
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Old 07-14-2016, 01:00 PM
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I cant imagine the motor bearings take an axial load equivalent to the force of pushing this boat along very well

Ill stick with the thrust bearing.
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Old 07-28-2016, 05:08 PM
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It can easily take it but you are free to believe what you want but I have to ask you then how can the thrust bearing ever touch the strut unless its too short and does so in wind up with a flex shaft and flex collet in the first place? Then look up thrust bearings to show one actually rated for 25,000 to 30,000 or higher rpms. If it's too short and and it touches the back of the strut it puts undue stress on the flex and it will rob rpm and or break. Once you lose enough props maybe you will reconsider . If its not too short the strut will never touch the thrust bearing and the motors bearings will bear the axial load anyway so again its useless with a non floating flex shaft setup. Not to mention the photo it is larger in OD than the strut tube so it is also creating unnecessary drag further slowing the boat. It is a lose lose. I'm trying to help you set the boat up in a way that will be more practical reliable and run faster but again you can stick with it.

For another example ask yourself.
Does a direct drive electric plane or ducted fan model have a thrust bearing between the prop hub and motor? Do you imagine in climbs against gravity that they don't create significant axial loads?

Last edited by AMB; 07-28-2016 at 07:10 PM.
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Old 07-29-2016, 10:38 AM
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Amb is correct. You need some space between the strut and drive dog. Also a thrust bearing is more suitable up at the motor, not at the prop/shaft.


What most likely happen was: under load and extreme rpm, your flex shaft actually tightens up and shrinks... You have everything flush, so when your at WOT your shaft can't shrink like it's supposed to and it snaps the flex shaft and you loose your beautiful prop.

You need to get rid of the thrust bearing, and leave a quarter inch between the strut and drive dog.
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Old 08-06-2016, 01:54 AM
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Here is a photo from a former NAMBA record holder James Allen that may give you an idea how to keep a prop in the event of breaking a flex shaft. This idea or one similar can be easily facilitated many different ways.

Good Luck.
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Attached Thumbnails Prop for a Delta Force 33 PLEASE-prop-retaining-system.jpg  
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