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-   -   Prop mods (https://www.rcuniverse.com/forum/speed-rc-gas-boats-236/6725794-prop-mods.html)

w3bby 12-08-2007 05:56 AM

RE: Prop mods
 
As Jamie said earlier, GOOD THREAD [sm=thumbup.gif] thanks for the replies guys. Pictures and diagrams make everything easier to follow along with handling comments.
I have some work to do over the winter now :D
Keep the comments coming..........

martno1fan 12-08-2007 07:17 AM

RE: Prop mods
 
a picture is worth a thousand words ;) Zac nice video she was running well before the prop disintegrated [X(].Any tips on what you do to stop this happening?apart from dont mod the bugger to start with :D.Can you explain the heat treatment you mentioned do you just heat it up and let it cool slowly or?

Believe It 12-08-2007 08:09 AM

RE: Prop mods
 


ORIGINAL: DaveMarles

My take on this is its not so much the prop mods as boat setup. Many of the prop numbers being talked about here are too big for me and might produce a good terminal speed after a 100 metres on some choppy water but for racing are a waste of time. They will run if I lift the strut a lot but then the boat handling is ugly. I like to run high rpm on my monos and a modded 7016/2 gives the best top speed on the GPS but a stock 7015/3 gives me the best laptimes by far, good acceleration out of the corners and good speed but the setup on the strut is completely different. To get the revs on the 7015/3 compared to the 7016/2 I have to lift the strut about 3mm or so and give it a touch of down angle (negative?). I don't use tabs but if the boat leans to the right I tilt the bottom of the rudder out to the right by a tiny amount (looking from the back of the boat)and that levels it up.

I found for some reason the 7015/3 made my mono quite loose, no matter where i set the stinger. The 7016/2 (mines quite modded) gives good speed like you mentioned, but way too unstable for my likings in heat racing as well.

Everyone has a different "liking" to how their boat handles and how they must control it during a race.... for me i go for the prop that lets me run lane 1 full bore through the turns \without losing much if any RPM, while staying pretty stable. Which on my Insane mono's, sofar has been a X472/2 for moderate choppy water, and a pitched up X467/2 for when it gets really rough. I give up speed through the straights with these props, but pull hard through the turns without ever having to let off the trigger and wonder out into the rigger lanes to keep the boat from trying to do stupid stuff. The ABC MW3 sofar has been the fastest that ive tested by about 3-4mph, but nowhere near as stable in the turns, and also drops RPM a bit through the turns.

Doubledog 12-08-2007 09:04 AM

RE: Prop mods
 
OK another subject.....

STAR tips vs ROUND



Let the discussion continue:D

Believe It 12-08-2007 10:42 AM

RE: Prop mods
 


ORIGINAL: Doubledog

OK another subject.....

STAR tips vs ROUND



Let the discussion continue:D

For what hull ;)

w3bby 12-08-2007 11:02 AM

RE: Prop mods
 

ORIGINAL: Doubledog
STAR tips vs ROUND
Please expand........ Are we not back to what do we want the prop to do?

Ron Olson 12-08-2007 11:36 AM

RE: Prop mods
 
There is a thread pinned to the top of the General boating forum with a lot of help on props with lots of sites that help you figure out a lot of things.
Yeah, Jamie should warn people first about looking at his props and hardware, sometimes they're like looking directly into the sun![sm=shades_smile.gif]

Doubledog 12-08-2007 01:15 PM

RE: Prop mods
 
I'm sorry Ian. You'll enjoy this portion as well.;)

Can someone please explain how STAR pointed vs ROUNDed tips effect performance. Lets start with a mono as thats what the orriginal application is for.
Tell us what else is needed as far as strut heights etc. (ps, I've got a basic understanding but not enough).

Jamie

w3bby 12-08-2007 07:57 PM

RE: Prop mods
 

ORIGINAL: Doubledog
I'm sorry Ian. You'll enjoy this portion as well.
No need for that, I think you misunderstood, I meant that tip shape affects the way the prop works, more or less lift, thrust cone angle etc etc and therefore relates back to your original question to me in post#2 "What exactly do you want to accomplish with the prop mods? " I would love a good explanation as well....

Zac Price 12-09-2007 08:10 AM

RE: Prop mods
 


ORIGINAL: dwr9

After trying a number of props on my mono the ABC 3014 in stock form, just balanced and sharpened, is the fastest. The 2716 with no mods was just about equal in speed but bogged in the corners. Doug

Doug,
On the 2716, I'd remove some tounge untill it pullled trough the turns and maybe a small barr cut.



.Any tips on what you do to stop this happening?apart from dont mod the bugger to start with .Can you explain the heat treatment you mentioned do you just heat it up and let it cool slowly or?
That barr cut was a bit extreme but worked the best After I get the prop to where I want it I put it in the oven on self clean mode for 2 hours. Make sure it's the way you plan on leaving it becase it will be hard after treated and don't even think of trying to bend one as they will break.

Now for a tip......
Find a prop that runs good in stock form, trim the tounge and add cup..... normally good for 3-5mph.

martno1fan 12-09-2007 08:17 AM

RE: Prop mods
 


Thanks mate now heres another question how do i add cup ?can you explain in some detail it would be much apreciated.

martno1fan 12-09-2007 08:35 AM

RE: Prop mods
 
1 Attachment(s)
Hi is this where and how to remove the tongue on an x series prop? pic one second pic shows back cut 3rd bar cut whats the diff between the two? also in the other pic showing the lines where to bend etc is this called cupping or is it just the line d on the outer edge thats the cup? sorry for all the questions im just trying to work this out.lots to learn for me anyways lol.

Zac Price 12-09-2007 12:42 PM

RE: Prop mods
 
To add or remove cup, do the bending @ 70% out from the hub. I took a screw drive and cut most of it off and put a drive dog on it to use for bending. I use a set of cupping pliers made by Mike Tyson (T-Mod muffler guy).

http://www.americanrcboats.com/images/misc/Nl29082.jpg

martno1fan 12-09-2007 12:54 PM

RE: Prop mods
 
Do i need cupping pliers then or can it be done without ?dont be affraid to explain things in detail to me im very dumb when it comes to this kind of thing ,im not affraid to try things out just need a few pointers to get me on the right track.Any pics of the tool you made and how its used would be great .

Doubledog 12-09-2007 01:12 PM

RE: Prop mods
 
Mart, I've got a set of cupping pliers as well. Mike Tyson does them. I don't have a picture handy, but take a simple cheap pair of pliers. Grind off the teeth & make it smooth grip. Next, round one jaw with sort of a hump in the tip. Thats it.

http://www.performance-inc.com/Images/tips/cupping.gif

Doubledog 12-09-2007 01:14 PM

RE: Prop mods
 
Also as a last resort, take a regular pair of pliers and gradually bend the tips. Be careful not to gouge the metal. I've done it in a quick fix & it worked fine.

martno1fan 12-10-2007 06:57 AM

RE: Prop mods
 
thanks mate now i have a clear idea of how its done im sure ill manage ill have a go at making a set of those pliers too cheers for the pics and info .i think ill try the back cut on my prather prop and remove the tongue and see how it goes before doing anything else.might order a few of these cheap ali props too and experiment a bit ;).im running one on my boat with good success so far.

w3bby 12-10-2007 12:10 PM

RE: Prop mods
 


ORIGINAL: Doubledog
OK another subject....
STAR tips vs ROUND
Let the discussion continue:D
Any one care to enlighten us?

dwr9 12-10-2007 05:52 PM

RE: Prop mods
 
Thanks Zac. I may just give that a try next spring. Doug


ORIGINAL: Zac Price



ORIGINAL: dwr9

After trying a number of props on my mono the ABC 3014 in stock form, just balanced and sharpened, is the fastest. The 2716 with no mods was just about equal in speed but bogged in the corners. Doug

Doug,
On the 2716, I'd remove some tounge untill it pullled trough the turns and maybe a small barr cut.




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