mopartybob

Hi all, maidened my 1/8 Miss Bud sunday,stock260 w/p280/2 blade,ran real good up to about 35-40mph,then it became a one-point hydro(ridin the prop LOL),but was able to ride it at will without blowin off...[:-],(allthough i had to gently nudge my son to ease off the throttle),it settled down gracefully,but would do it again when more than 1/2-3/4 throttle is applied at runnin speed,I know the proboat bud has COG issues to begin with,but when my wife purchased the hull for me, (),it was set-up with the strut already shimmed down aprx. 3/16", and about 6-8oz. of flat lead on the front canard. I scooted the fuel cell as far forward as i could also,My ? is the airfoils that buddriver13 came up with(pic below),has anyone really done any useful evaluation on them or used them with different heights for any success??? my bud is to the point that it's almost trimmed to where it needs to be,but without relocating the engine,or adding another 6-8oz. of weight,would the airfoils add enuff downward force to make the difference??( this and tweaking the rear horz. stab.) ???,....thanks for any input

OLD_SLOW and in the WAY

a hydro should balance at the rear of the sponson give or take a bit for a particular hull. that canard on the real boat is an active component and changes attitude whilst its at speed. although riding the boat in a "wheely" might be a crowd pleaser its not the fastest way around and will blow off before you can say oh oh. so balance the boat out and set the front fin/canard at zero degrees and try it

mopartybob

thanks buddy,I just rechecked the COG and YIKES !! it's like 7 1/2" behind the lowest part of the sponson...[:@](not good),I got out 20oz. of fishing weights and it put the COG at about 4"behind the sponsons,I think it was mentioned elsewhere that you want it at about 3",...[:-],so ...mmooooving right along under the ASSumption(hate that word) that I'm NOT going to relocate the engine(yet....),has anyone opened up the sponsons and added weight(s) to the point that the right sponson is heavier than the left??ie:14oz. r/s...10oz. l/s(just to add more bite to the turn fin) is this recommended??....please bear with me ya'll,my first hydro....[:-]

OLD_SLOW and in the WAY

add the weight as far forward as possible so you dont have to add as much

OLD_SLOW and in the WAY

add the weight as far forward as possible so you dont have to add as much

mopartybob

I had the extra weights sitting on the front canard,not much forward left but to go inside the sponson to the tips....[]

Hydro Junkie

Okay, lets look at what you can do to this boat to rebalance it:
1) Move the radio box into the cockpit and the fuel tank under the deck on the right side along side the engine or as far forward as you can
2) Build a lighter rear wing using Balsa, lite ply and aircraft grade ply
3) Add weight to the sponsons at the tips, making the amounts either equal or slightly LEFT SIDE HEAVY
4) Last resort, relocate engine further forward

Your problem, as you already know, is too much weight in the rear. By moving things forward and/or replacing parts with lighter ones, it will make a difference. Moving the engine and adding weight are last resort moves, especially moving the engine

mopartybob

thanks HJ,the ideal COG is 3" behind the sponson???

Hydro Junkie

You're not going to like this, but more like 1-2"

BB Modss

Bob at this point...pull the boat apart and rebuild it... If your not at proper cog after all this work then start fresh.. Or you can run that 47" 3 point hydro i have on the shelf It was a district 19 record holder for a long while.

mopartybob

[:@]...lol....SOOooooo,now i'm looking at adding possibly another [:@]30-40oz. of lead !!!thanks for the honest info guyz,it should be done right,and will be.....this is gonna be fun...[:-]

mopartybob

This rebuild will be a GREAT learning experience for me and my 11yro. son, So thats what we iz gonna do....[8D]...THANKS Tom,YOU'VE GOT MAIL....

Proboat 772

Before you carve your boat up, I'd like to offer a few suggestions based on 2 seasons of tweaking our 3 Proboat Hydros ( Bud, Llumar and Elam ). We have these boats running 45 MPH with stock engines and able to run flat out all the way around the course.

First, I'd suggest checking your strut angle for excessive shimming. Remove your turn fin, rudder and prop and put the hull on a table. The bottom of the strut should be flat or just very slightly high at the forward edge. If there is too much lifting thrust, the boat will become very unstable with the sponsons in the air and bouncing from side to side. Each hull is a little different, but .080 to .125" tapered shim worked for us.

Then add 10 degrees positive angle of attack on the rear wing to assist in lifting the rear of the hull. This provides greater lift the faster you go plus adds even greater lift when the bow attitude rises.

A front cannard spoiler at 40 degrees by 3/4" inch high full width of the cannard will keep the sponsons tickling the water at full throttle. Again, the faster you go, the more downforce is created.

Lastly. changing the turn fin and rudder will work wonders, allowing the boat to turn on a dime and give you change. We custom fabricated ours from .080 aircraft aluminum alloy.

These are just suggestions as a starter. There is more that can be done to further refine the hull. (On this one I moved the engine forward 1/2" ).

I'll upload a few pictures of the Llumar.

Dick Thompson

mopartybob

Thanks D Thompson,simple ,effective mods...worth a try before the boat goes under the dremel...[:-]

BB Modss

Iv got a QD 25 and one of my full mod 260's here we could stick in there.. Ill send that QD over with the new hydro.

mopartybob

Outta-site Tom, my package ships out tomorrow.....,Proboat 772, the custom front canard on the Llumar,was that angle increased or decreased or is it/can be? adjustable for water/wind conditions??

Proboat 772

I made a wrap of .016 Aluminum over the cannard with the rear edges bent to accept different size blades. First I used an Aluminum blade, then a piece of acrylic that you see in picture, secured by clamping with screws. Even though i have several sizes, ( 3/4" and 7/8" ) the smaller 3/4" high seems to work just fine. My spoiler angle is 40 degrees. You also can use the Monster Truck spoiler that Bud Driver has on his boat and that works fine also. I'll paint the Aluminum to match the hull after I finish testing.

mopartybob

I used 1/4 scale servo arms for the rear wing mod,I can now adjust for anywhere from 10-30 degree's of lift...too simple...,I'm considering making the front canard fully adjustable as well..[:-]let us know how testing goes.....

Proboat 772

Gret idea! I made my links on the bandsaw from aluminum. On the rear wing 10 degrees seems about right. as you go higher, you'll increase draag. Go down the road at 40 or 45 MPH, put your hand out the window at 10 degrees an see how much lift you get.

BudDriver13

Some great mods on this post guys!!

Hydro Junkie

Bob, Proboat 772, you both are forgetting something. THE REAR WING IS NOT DESIGNED TO LIFT THE REAR OF THE BOAT, IT'S USED TO FINE TUNE THE BOAT'S RIDE AFTER THE BOAT IS BALANCED. It works the same way on the full sized boats as well. Set your wing to zero degrees and balance the boats from there, then fine tune with the wing. I just had a thought. What happens if you blow the boat over and break the wing? Now you've lost the lift and you are back to the same problem all over again.

mopartybob

Thanks HJ,I was wondering when you would help clarify this ...A worthwhile mod though AFTER the boat is ba-lanced,what about havin the front canard adj.,have you explored this option?? as always,thanks for your valuable input....[8D]

Proboat 772

We run our boats flat out - we haven't had a blowover yet. Can only pass along what we found works - then you decide if you want to use it or not.....

Proboat 772

We run our boats flat out - we haven't had a blowover yet. Can only pass along what we found works - then you decide if you want to use it or not.....

Hydro Junkie

I've seen scratch built boats with teh whole canard made to pivot, but never took the time to go really look at how it was set up. It does work well for those that did them