Canard CG??

[K.R.Joye]

Its been a while since i set one of these up. I aquired a vintage 32" K&B O/B semi-scale canard hull(similiar to one in pic). I'm thinking of running it as an inboard with surface drive to compete with some local Sport 40's.

Some questions......

Is this hull legal for NAMBA / IMPBA competion? If so what classes?

Where do i start with CG? Since the hull was designed for an O/B it must be fairly far back.......

This hull has a shallower left sponson then right sponson any ideas on why this is?

Your opinions are welcome!

 

[Buddy Benedict]

Canards are not legal for sport 40 in IMPBA.

From the online rulebook.

Hull must be a three (3)-point hydroplane configuration and resemble a limited or

unlimited hydroplane design of past or present, except outrigger, modified outrigger,

tunnel, or canard hulls are NOT permitted.

Buddy Benedict

My guess is the only class its legal for is the hydro(rigger) classes.

 

[norm j]

hello, i have the same boat, its mrp python,i'll look at the set up plans to see if there was a reference to where the cg is,as i recall there was not one, is your boat a 20 size or 40 size?in the impba you can run it in a hydro class, although you will be behind the 8 ball with the other rigger style boats, you still can have some fun with it and who knows you could still take some points as well,just set the boat up to be steady and consistant,alot of time the other boats in a heat may not finish!! one other thing,the one sponson deeper than the other,is supposed to counter prop torque, you got a picture of the boat in question?

good luck!!

norm j

fmbc

glmbc

 

[SayMikey]

hello, i have the same boat, its mrp python,i'll look at the set up plans to see if there was a reference to where the cg is,as i recall there was not one, is your boat a 20 size or 40 size?in the impba you can run it in a hydro class, although you will be behind the 8 ball with the other rigger style boats, you still can have some fun with it and who knows you could still take some points as well,just set the boat up to be steady and consistant,alot of time the other boats in a heat may not finish!! one other thing,the one sponson deeper than the other,is supposed to counter prop torque, you got a picture of the boat in question?good luck!!

norm j

fmbc

glmbc

Had one with a 7..5 k/b outboard ran great

 

[NITROSNIFER]

Don't want to hijack your thread but I also had a Canard and am trying to get it to run properly. Have had limited success and am now thinking the CG is off. I was forced to move the engine back due to getting the pipe length correct. It's a 81' Circus Canard I currently have the CG set at the tips of the Canard wings. Boat still runs with the nose in the water and at times does come out. Any help would be great as it runs different than my other Canard and yet they are very similar boats.

Kevin

 

[NAMBA860]

Don't want to hijack your thread but I also had a Canard and am trying to get it to run properly. Have had limited success and am now thinking the CG is off. I was forced to move the engine back due to getting the pipe length correct. It's a 81' Circus Canard I currently have the CG set at the tips of the Canard wings. Boat still runs with the nose in the water and at times does come out. Any help would be great as it runs different than my other Canard and yet they are very similar boats. Kevin

is you canard a fisher design or the gaines/fritz design? best thing to do is run the boat with the strut as high as possible just till it starts to cavitate down the back straight then bring in down a red c hair. run the strut at a neutral level make sure the boat has a 2 blade prop on it. if its a .67 engine probally something like an x457 or x460 depending on the h.p. of the engine. you basicly set it up like a mono hull but the rudder on the left side.i worked for mr. gaines for a couple years and is a good friend of mine as well to this day. he took the scale canard to the wind tunnel at texas a/m university. the rear sponsons of the gaines/fritz canard are much more superior then the fisher canard.if you ever want to sell one of your canards let me know. im currently running a gaines canard right now its scratch built not the scale version with a mac .67 blue head. im having alot of fun with this boat right now,shane

 

[jayt]

Where do i start with CG? Since the hull was designed for an O/B it must be fairly far back.......This hull has a shallower left sponson then right sponson any ideas on why this is?

Canards have the advantage over riggers in cornering ability; set up right they should run like a cat through the turns without the sliding that riggers often experience. The rear sponsons also keep the prop from running too deep which helps keep the motor on the pipe for higher exit speeds. On the straights the front sponson should be in the air. The CG needs to be just in front of the center of lift - which is mostly supplied by the rear "wings". This is easier to dial-in with an FE version than with a fuel setup. Set up this way it is tough - but not impossible - to blow over a canard.

The right sponson is deeper to allow it to dig in better in the turns - since a turn fin is not run something has to hold the boat on the buoys. Some winning cat and OPC designs have this same feature as well.

.

 

[NITROSNIFER]

Well 3.5 hours at the pond and I figured it out got the CG right a 450/3 and it hauls. That only took me 3 years to figure out :lol: . I got it now though and can't wait to race it

 

[NAMBA860]

Well 3.5 hours at the pond and I figured it out got the CG right a 450/3 and it hauls. That only took me 3 years to figure out :lol: . I got it now though and can't wait to race it

thats an pretty small prop for .67 hydro. i run that on my .45 mono

 

[NITROSNIFER]

Sorry my Bad it's a X455/3. I tried a Prop shop X457 and a Props4u X460/3 it did not like either of them. So I went back to the 450/3 and away she went. My other canard liked the 460/3 as does my Winston Eagle. Here's some pics of my Canards.

 

[K.R.Joye]

The right sponson is deeper to allow it to dig in better in the turns - since a turn fin is not run something has to hold the boat on the buoys. Some winning cat and OPC designs have this same feature as well.

.

Hey Jay thanks for the great response, I thought because the hull was originally designed for O/B the varing rear sponson depths were designed to offset the combination O/B moment arm/prop torque. When i set it up on 4S-5S lipo for inboard surface drive do you think the rear sponson design will still work well?

I plan on running from `fore to aft' MOTOR then- ESC then- BATTERY. The battery will be up against the transom in order to get the CG in the sweetspot. I'm planning to run the strut outword of the transom as far back as i can get it with an offset rudder(left side).

I'm am so jealous of your boats NITROSNIFER! Any pics at speed?

 

[jayt]

In 1988 there were several factory-modified Pythons with 3.5 and even 7.5 motors installed - see photo below. The report stated that the 7.5 idea worked great and that the boat turned better with glued-on ride pads - presumably to sharpen the sponson edges.

I'd try the factory sponsons first, it won't be too tough to modify them if they don't work.



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