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Nov 11, 2021, 12:04 PM
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Hey guys! Did a little work to my Rocket and tried her out on 5s ..pretty cool! I don't know what I hit at the end of my run after filming stopped, but look at that prop! My initial thought was that it simply hit the rudder, but I was doing a speed run (in a straight line and in the middle of the lake) when the boat just flew up into the air. I immediately noticed something wasn't right after it landed and discovered the mangled prop when I got her back to shore ..feel like something else would have snapped or cracked before the prop could have ever touched the rudder, ya know? ..maybe something got wedged in-between them for a second. Anyways, time to get a new prop and do it all over again

Joysway Rocket V2 (aka Atomik Barbwire XL) / 5s / GPS 55mph - 88.5km/h !!! (1 min 26 sec)


RCnerd's Rocket looks soooo good!!!
Last edited by Woods153; Nov 11, 2021 at 12:23 PM.
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Nov 11, 2021, 01:46 PM
Fast electric boats maybe
Jeffro Bodine's Avatar
Quote:
Originally Posted by Woods153
Hey guys! Did a little work to my Rocket and tried her out on 5s ..pretty cool! I don't know what I hit at the end of my run after filming stopped, but look at that prop! My initial thought was that it simply hit the rudder, but I was doing a speed run (in a straight line and in the middle of the lake) when the boat just flew up into the air. I immediately noticed something wasn't right after it landed and discovered the mangled prop when I got her back to shore ..feel like something else would have snapped or cracked before the prop could have ever touched the rudder, ya know? ..maybe something got wedged in-between them for a second. Anyways, time to get a new prop and do it all over again

https://www.youtube.com/watch?v=jMLMNmYI9A8

RCnerd's Rocket looks soooo good!!!
Have you considered it could have been a turtle that mangled the prop just a thought , because I've hit several over the years, great job with your boat 55 mph is hauling for a 26"hull.
Nov 12, 2021, 06:39 PM
Registered User
Quote:
Originally Posted by Woods153
Hey guys! Did a little work to my Rocket and tried her out on 5s ..pretty cool! I don't know what I hit at the end of my run after filming stopped, but look at that prop! My initial thought was that it simply hit the rudder, but I was doing a speed run (in a straight line and in the middle of the lake) when the boat just flew up into the air. I immediately noticed something wasn't right after it landed and discovered the mangled prop when I got her back to shore ..feel like something else would have snapped or cracked before the prop could have ever touched the rudder, ya know? ..maybe something got wedged in-between them for a second. Anyways, time to get a new prop and do it all over again

https://www.youtube.com/watch?v=jMLMNmYI9A8

RCnerd's Rocket looks soooo good!!!
That looks highly likely that the rudder/stand off has flexed over & contacted with the prop blades & bent them. Seen this happen before a number of times on various boats, you can see contact marks on the rudder blade.
Nov 19, 2021, 12:17 AM
Just Plane Nutts
AirDOGGe's Avatar
Man, that puppy is really worthy of the name "Rocket" now. Nice work.

Quote:
Originally Posted by martinh50
That looks highly likely that the rudder/stand off has flexed over & contacted with the prop blades & bent them. Seen this happen before a number of times on various boats, you can see contact marks on the rudder blade.

Same here. Most definitely looks like a rudder-prop strike. I don't see any damage on the front of the rudder that would suggest a foreign object strike (been there and it nearly ripped the rudder off).



A plastic (composite, they say) rudder strut is a flexy thing to be taking the loads you are putting on it. It was never designed for that much stress.

Try aftermarket metal parts,or replacement with metal parts from other boats that you can adapt to yours.



Last edited by AirDOGGe; Nov 19, 2021 at 12:25 AM.
Nov 19, 2021, 01:30 PM
Registered User
Yes if you look 1:18 into the video you can see the clear silver scratches on the rudder blade from prop contact.
Nov 20, 2021, 11:29 AM
Registered User

Joysway Rocket brushless


Thanks for the feedback, guys!

Airdogge - your rocket looks great. Do you remember where you got your rudder from? The length of support arm looks about the same length Iím looking for (60mm) but I just canít seem to find one that length ..60mm from transom to leading edge of rudder blade. Iíve seen a similar one that looks like yours by TFL, but itís 80mm and I donít know if that will be too long and/or change the way it handles. Thx!


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Nov 22, 2021, 01:52 PM
Just Plane Nutts
AirDOGGe's Avatar
https://www.ebay.com/itm/16370149539...sAAOSwsE1aF5bJ

The 100mm rudder's strut was shortened to fit my boat. I hack-sawed about an inch off, rounded the end off again with a tabletop disc/belt sander.





Instead of just drilling a 2mm hole in the strut for the hinge pin, I drilled a 4mm hole and pressed some short pieces of thick-wall (.095mm) 4mm brass tubing to make new bushings.

I finished the bushing's I.D. with a 5/32" drill bit followed by a 2mm reamer for best fit.



The strut was for a Miss Excite, but I had to shorten it a little and then deepen the step in the aft end bore with a bigger drill to fit the Barbwire's ball bearings proper.



I had several photos of the process in the Barbwire XL mod thread, but I think many were lost when the image hosting site I have them on shut down.

Latest blog entry: My You-Tube channel
Nov 22, 2021, 02:26 PM
Registered User
Jansvast's Avatar
Looks like it came that way, nice job!
Nov 22, 2021, 03:20 PM
Registered User
Yeah - great work and idea, airdogge! ..getting a longer rudder and shortening it didn't even cross my mind ..I was stuck on finding shorter ones and extending them lol, but shortening a longer one definitely seems better. You get to keep the nice base and support from the rudder arm instead of extending from the base of a shorter one with those little metal cylinder standoffs like I did. Cool, thx for all info.
Nov 22, 2021, 09:38 PM
Just Plane Nutts
AirDOGGe's Avatar
I found my old build posts for the rudder, but as I feared the images went away when IMGSAFE.ORG folded some 5 years back. I did not know at the time that RCgroups had so much storage space else I'd have upped them here.

Still, there might be useful info in the text. See post #455 in the Barbwire XL mod thread for the rudder shortening process, and post #466 for the bushing install. The latter was a suggestion from F.A.R.M.E.R. who gave a lot of tips on modding the barbwire XL.

https://www.rcgroups.com/forums/show...1#post32632763



Note that a Joysway Infinity Offshore strut and rudder will work too if you can find them. https://m.media-amazon.com/images/I/...L._SL1500_.jpg
Last edited by AirDOGGe; Nov 22, 2021 at 10:10 PM.
Nov 29, 2021, 04:04 PM
Registered User
Cool! I’ll check it out. I ended up putting a new metal rudder on, but I’m not sure if it’s high enough up on the transom. Is there a general rule of thumb for how high up on the transom to mount your rudder? ..when it goes by on the water it looks almost like it’s right on the line of being in the water (the bottom of rudder arm, I mean) ..it’s very close - might be a hair in, might be a hair above the water line. It’s prob 1-2mm lower than stock rudder arm ..still handles as great as it always has, but I’m wondering if it’s slowing the boat down if it is dragging a little bit because I fitted a larger 1750kv outrunner from the Vector SR80 Pro boat, ran it on 5s and had to run a 45mm prop to get 47mph and temps were getting hot (not that I expected that setup to run cool or anything lol). I know there’s endless variables related to top speed, but I see guys saying they’re getting 45-50mph with the boat that motor comes in on 4s with the stock 40mm prop, so I was expecting at least 50mph on 5s in the Rocket, ya know? Maybe the Rocket weighs more with the flood chamber, but still. On a good note, that bigger 1750kv motor gives me longer run times and faster speeds for longer intervals at cooler temps than that little 2845 outrunner that’s screaming for its life in the YouTube vid, but I’m on the verge of popping a 6s battery in there to get my 50mph ..but it has to be achievable with that motor and a 5s battery in the Rocket! I’m using cheap $15 CNC 1.4p props from China too, so maybe it’s time to explore some octura sharpened and balanced props?

Quote:
Originally Posted by AirDOGGe
I found my old build posts for the rudder, but as I feared the images went away when IMGSAFE.ORG folded some 5 years back. I did not know at the time that RCgroups had so much storage space else I'd have upped them here.

Still, there might be useful info in the text. See post #455 in the Barbwire XL mod thread for the rudder shortening process, and post #466 for the bushing install. The latter was a suggestion from F.A.R.M.E.R. who gave a lot of tips on modding the barbwire XL.

https://www.rcgroups.com/forums/show...1#post32632763



Note that a Joysway Infinity Offshore strut and rudder will work too if you can find them. https://m.media-amazon.com/images/I/...L._SL1500_.jpg
Last edited by Woods153; Nov 29, 2021 at 04:34 PM.
Nov 30, 2021, 08:34 AM
Registered User
Quote:
Originally Posted by Woods153
Cool! Iíll check it out. I ended up putting a new metal rudder on, but Iím not sure if itís high enough up on the transom. Is there a general rule of thumb for how high up on the transom to mount your rudder? ..when it goes by on the water it looks almost like itís right on the line of being in the water (the bottom of rudder arm, I mean) ..itís very close - might be a hair in, might be a hair above the water line. Itís prob 1-2mm lower than stock rudder arm ..still handles as great as it always has, but Iím wondering if itís slowing the boat down if it is dragging a little bit because I fitted a larger 1750kv outrunner from the Vector SR80 Pro boat, ran it on 5s and had to run a 45mm prop to get 47mph and temps were getting hot (not that I expected that setup to run cool or anything lol). I know thereís endless variables related to top speed, but I see guys saying theyíre getting 45-50mph with the boat that motor comes in on 4s with the stock 40mm prop, so I was expecting at least 50mph on 5s in the Rocket, ya know? Maybe the Rocket weighs more with the flood chamber, but still. On a good note, that bigger 1750kv motor gives me longer run times and faster speeds for longer intervals at cooler temps than that little 2845 outrunner thatís screaming for its life in the YouTube vid, but Iím on the verge of popping a 6s battery in there to get my 50mph ..but it has to be achievable with that motor and a 5s battery in the Rocket! Iím using cheap $15 CNC 1.4p props from China too, so maybe itís time to explore some octura sharpened and balanced props?
The stock 2845 motor is 2800kv x 4s = 41000 rpm unloaded, the larger 1750kv motor on 5s is only 32000rpm unloaded. Even running the larger 45mm prop on the larger 1750kv motor is not as fast as the stock motor on 4s. The stock motor on 4s gets extreemly hot though.
Nov 30, 2021, 09:49 PM
Just Plane Nutts
AirDOGGe's Avatar
I think I'd drop to a 2200Kv-2300Kv for 4S juice.
Latest blog entry: My You-Tube channel


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