Rear Ski for RTR sport hydros

[raytam]

Hi all,

I'm realy impressed with the Design of JAE riggers. Did anyone try using the rear ski design on a miss vegas/miss bud? If yes, did it increase or decrease performance?

Is it a good or bad idea? I'm thinking of trying this to see if it will help in anyway. I cut some garage foam and made a little ski for my stock Miss V Deuce. Riggers in general are much lighter which helps in many ways, but do you think the ski will help this boat out too? Once weather permits, I'll be out testing hopefully with good video and gps.

This boat has been really fun to mod. Here's the progression.

Stock boat, with no wing, octura y535 prop and 50% nitro = fastest speed per gps = 43.5mph.

At this speed it was really unstable and flipped one time.

Next mod, I added an airdam (UL-1 style) to reduce risk of flipping. With same prop, but with 60% nitro, the fastest so far is 41.8 mph.

I suspect the plugs I'm using are too warm. i noticed that my air dam did reduce the flipping tendency but the boat tends to go subsurface more than before. I believe I'm going remove the mod at my next test and tune session and try this new rear ski.

After this mod, I'll try applying a thin piece of ply over the front sponsons to produce some overhang and reduce tension.

Thanks for reading

Ron

 

[NAMBA860]

Hi all,

I'm realy impressed with the Design of JAE riggers. Did anyone try using the rear ski design on a miss vegas/miss bud? If yes, did it increase or decrease performance?

Is it a good or bad idea? I'm thinking of trying this to see if it will help in anyway. I cut some garage foam and made a little ski for my stock Miss V Deuce. Riggers in general are much lighter which helps in many ways, but do you think the ski will help this boat out too? Once weather permits, I'll be out testing hopefully with good video and gps.

This boat has been really fun to mod. Here's the progression.

Stock boat, with no wing, octura y535 prop and 50% nitro = fastest speed per gps = 43.5mph.

At this speed it was really unstable and flipped one time.

Next mod, I added an airdam (UL-1 style) to reduce risk of flipping. With same prop, but with 60% nitro, the fastest so far is 41.8 mph.

I suspect the plugs I'm using are too warm. i noticed that my air dam did reduce the flipping tendency but the boat tends to go subsurface more than before. I believe I'm going remove the mod at my next test and tune session and try this new rear ski.

After this mod, I'll try applying a thin piece of ply over the front sponsons to produce some overhang and reduce tension.

Thanks for reading

Ron

IN MY OPINON YOU JUST ADDED A BUNCH OF WETTED SURFACE TO THE BOAT MORE DRAG. IF THE BOAT IS SET UP CORRECT THE PROPELLER SHOULD LIFT THE BACK OF THE BOAT AND CARRY IT. THATS WHAT MINE DOES AND IT RUNS IN THE LOW 50,S

 

[raytam]

Thanks 860, I agree with you about the extra wetness, but if the JAE riggers also have that extra wetting surface, why are they as fast as they are compared to other riggers without the ski? I'm just trying to understand this myself. So that is why I question it...no direspect intended.

Thanks

 

[M@MRacing]

I totally agress about the wetted surface plus you just made you RTR illegal to run with the RTR boats

 

[raytam]

I totally agress about the wetted surface plus you just made you RTR illegal to run with the RTR boats

Legality in RTR classes was another question I thought of asking, but have not presented yet...thanks for answering the question before it was even asked

 

[misshydro]

Thanks 860, I agree with you about the extra wetness, but if the JAE riggers also have that extra wetting surface, why are they as fast as they are compared to other riggers without the ski? I'm just trying to understand this myself. So that is why I question it...no direspect intended.

Thanks

Look at the wightness other that rigger compared to the vegas.. The vegas is wider accross the bottom then the rigger.Plus your adding more weight to that vegas..Those Miss Bud's and Miss Vegas are very sencitive to any weight changes to the hull..add more weight= slower speeds and sometimes they can performance badly too..The only mods there let you do to the hull is sponsons and blue printing the bottom plus top of the hull & paint are legal...A three blade prop would be your lifting prop.

 

[raytam]

So, regardless of the 25mph gusts and 6 inch chop, I took my Vegas ski boat out today to run a couple of tanks. I didn't get video. But here are my results... Again, this is a stock MV deuce with stock engine, 60% nitro, indexed mc 9 plug (BB mods, I see why this is a favorite...it lives through 60% even when lean) cmdi b/s y535, and the rear ski.

I only had a change to do a few runs but the double sided tape didn't hold the ski on for more than 5 short runs.

First run with y535, the immediate improvement is that it gets on plane in less than 1/2 the distance without the ski. Negative improvement was on top speed...the prop was too small. Without ski, the 535 is the largest prop this engine can pull (it can't even spin an m435 3 blade). I leaned out the fuel and the fastest speed on gps was 22 mph going down wind.

third run was with a grimracer 42x55. Again, on plane like cake, but it took about 40 yards to get on pipe. Once on pipe, the boat, with the help of chop, was flying out of the water. I did back off throttle...the fastest on gps = 36.9 mph.

Fourth run was with a cupped octura x438 3 blade. It didn't even get on plane...too much cup.

Fifth run was with a x438 3 blade b/s by dasboata. This was more like the 42 but it really never got on pipe like the 42. I'd say it ran may be 30mph but I lost the ski in a turn.

My opinion...the ski does help in certain ways, but the boat needs more tuning. I'm going to make another ski but thinner in width and use epoxy to attach it. The last ski only weighed 1/4 ounce.

Hopefully next time out, the winds will be more gentle and the water will be less choppy...and have some video.

Would this be illegal to run in a mod rtr class?

Just trying to think out of the box...the JackAss Engineering way, even though I'm not JAE. lol

Thanks for reading.

Ron

 

[M@MRacing]

Yes the ski is totally illegal just work on your set up on that boat it will fly without that ski

 

[raytam]

What a bummer. The boat flies stock...41 to 43mph stock is very good. The original vegas was not this fast. Back to the drawing board.

MM racing - is the attachment of 1/64" or 1/32" ply to the bottom of the front sponsons legal? If yes, then a little overhang would be just as good as knife edge corners.

Thanks

ROn

 

[153stars]

What a bummer. The boat flies stock...41 to 43mph stock is very good. The original vegas was not this fast. Back to the drawing board.

MM racing - is the attachment of 1/64" or 1/32" ply to the bottom of the front sponsons legal? If yes, then a little overhang would be just as good as knife edge corners.

Thanks

ROn

Is a flat bottom strut legal? in IMPBA I know it can be only so big for hydro in NAMBA I don't think they allow them in hydros.

 

[M@MRacing]

They use flat bottom struts on scales and sport40 in namba also check with your district every district varys.

 

[153stars]

They use flat bottom struts on scales and sport40 in namba also check with your district every district varys.

I was wondering if a flat bottom strut/strut change is allowed in RTR classes. Seems like it would help org. vegas hull or break out the JB weld and build up the original.That must be a hunk of mud on my strut :unsure:

 

[misshydro]

They use flat bottom struts on scales and sport40 in namba also check with your district every district varys.

I was wondering if a flat bottom strut/strut change is allowed in RTR classes. Seems like it would help org. vegas hull or break out the JB weld and build up the original.That must be a hunk of mud on my strut :unsure:

I think I saw some that had that setup and was aloud to run them..