F1 bottom tunnel "notches" question

[drumzzzz]

Does anyone know what the purpose of those inside rectangular notches(on stringers) found on most f1 tunnels sponsons are for?

here's some pics:

http://www.philippe-dessertenne.com/item_i...2005%2003:25:22

Are these some sort of inner water deflection/strake?

I also note a forward stepped running surface on the bottom center hull- are these a form of stumble blocks?

seems a more streamlined way of doing it

 

[Grimracer]

drum,

Im not sure but i bet the long inner keelsons are for lift. Also the center is likely as much for stability as it might be for stumble.

grim

 

[Jack Garcia]

drum,

Im not sure but i bet the long inner keelsons are for lift. Also the center is likely as much for stability as it might be for stumble.

grim

I agree Mr. Grimracer. The long fore and aft step helps the boat get on plane much sooner. And the center raised area is to keep the nose from diving in the turns. In a sense, a stumble block.

 

[VansRacing]

Drum,

F1 tunnels turn much tighter and set down much harder than R/C tunnel boats do in reference to scale. Look back at the picture you posted and notice how high these inner strakes are placed in the tunnel. They are mostly clear of the water at speed other than deflecting a slight amount of spray at the rear.

When a F1 tunnel boat sits down to make it's turn, the boat has to bite hard to pull the boat around the buoys. Tunnel boats by design love to turn and if allowed to, they will turn too tight. These strakes help form a soft spot in the turns and help keep the sponson from an over bite situation or sitting down harder than what is needed to make the turn.

They also help lift the boat back out and off the turn quicker. The point is to get the sponson dried out as quickly as possible coming out off the turns. All this takes place deep in the turns and has little and probably nothing to do with mid-range to top end speed.

If you'll notice, these inner strakes are all very simular but different makes of full size tunnel boats have them positioned at different depths and have different widths depending on the design of the boat and its needs in the turns.

Rod Geraghty introduced this type technology to R/C tunnels in the early 80's and revolutionized the O/B tunnel boat design.

-Carl,

 

[Geraghty]

In a sense, a stumble block.

That is exactly what they are.They are the F-1's answer to the stumble blocks.When in the corner the rails only let the sponson sink to the depth of the rails.

That works real well on the full scale boats because they want to go around single pin turns.Essentially they want the boat to go into a "controlled" hook while turning.You will also need power trim to make these rails work.

They don't work very well on the models because we have a much larger turn radii and don't want the boat to hook,ever.The stumble blocks make the turn radii very linear in relation to rudder input.

 

[racejunkie538]

If you look to these pics you will see this German F1 tunnel use the same concept, and I can tell you it works realy well.

Greets Marc

 

[jayt]

They also function as integral spray rails, keeping water spray out of the tunnel for reduced drag and cleaner airflow though the tunnel. Jay Selby wrote an extensive series of articles in RCBM in the late 80s about tunnel boat design, and their design and function were mentioned in his work.

 

[drumzzzz]

Drum,

F1 tunnels turn much tighter and set down much harder than R/C tunnel boats do in reference to scale. Look back at the picture you posted and notice how high these inner strakes are placed in the tunnel. They are mostly clear of the water at speed other than deflecting a slight amount of spray at the rear.

When a F1 tunnel boat sits down to make it's turn, the boat has to bite hard to pull the boat around the buoys. Tunnel boats by design love to turn and if allowed to, they will turn too tight. These strakes help form a soft spot in the turns and help keep the sponson from an over bite situation or sitting down harder than what is needed to make the turn.

They also help lift the boat back out and off the turn quicker. The point is to get the sponson dried out as quickly as possible coming out off the turns. All this takes place deep in the turns and has little and probably nothing to do with mid-range to top end speed.

If you'll notice, these inner strakes are all very simular but different makes of full size tunnel boats have them positioned at different depths and have different widths depending on the design of the boat and its needs in the turns.

Rod Geraghty introduced this type technology to R/C tunnels in the early 80's and revolutionized the O/B tunnel boat design.

-Carl,

I definitely like your hull design with the slight recess built into the back of the hull, when looking at pictures on plane it seems very effective. Do you think a similar slight recess/or strake design on the inner side would help on straightaways, or be a bit of overkill?

 

[drumzzzz]

If you look to these pics you will see this German F1 tunnel use the same concept, and I can tell you it works realy well.

Greets Marc

Wow, great pics! Is that a .67 tunnel? How well does it perform compared to standard tunnels?

 

[racejunkie538]

Drumzzz

The tunnel performs realy well for an 1.35m lenght tunnel with QD outboard.

The speed at this moment is 94,1 kmh

I'm building this tunnel also with a tuned Zen 260 outboard and will be ready at spring 2006.

Greets Marc

http://i11.photobucket.com/albums/a184/rac...8/ArianFull.jpg

http://i11.photobucket.com/albums/a184/rac...538/QDArian.jpg

 

[james irwin]

Does anyone know what the purpose of those inside rectangular notches(on stringers) found on most f1 tunnels sponsons are for?

here's some pics:

http://www.philippe-dessertenne.com/item_i...2005%2003:25:22

Are these some sort of inner water deflection/strake?

I also note a forward stepped running surface on the bottom center hull- are these a form of stumble blocks?

seems a more streamlined way of doing it

SOME PEOPLE THINK THEY WORK, THEY ARE IN THERE FOR AIRYATION. I WILL TELL YOU FROM MY ON PERSONALE EXP/ THEY WILL WORK GREAT ONE A STOCK BOAT . THEY WILL KEEP THE NOSE UP TOO HIGH FOR A GOOD MOD BOAT . IF YOU THINK I AM WRONG TRY THIS , SET THE BOAT ON A FLAT SURFACE . MEASURE THE NOSE HEIGHT , IF YOU LOOK UNDER THE BOAT YOU WILL SE IT SITTING ON THOSE STEPS, NOW SAND EACH STEP AND LOWER THE NOSE BY 1/8 , NOW RUN IT AGAIN , WELL I WILL BE DARNED , THE OL NOSE DID COME DOWN . HE HE GOD BLESS

SORRY GUYS I MISS READ WHAT THE QUESTION WAS , I THOUGHT HE ASKED WHAT THE GROVES ACROSS THE SPONSENS WERE FOR . AGAIN , SORRY ABOUT THAT .