The Wall

[Slideblues]

That could be Chris, the application of power thru a 3.5 sec record run would be critical.

Yea read that Chevrolet will no longer supply engines to the Indy Racing League after 05, And they were not interested in the Champ series either.

Gene

 

[Chris Wittrig]

Hmmm....could it be because the Chevrolet was really as Cosworth platform and Cosworth sold to two principals in Champ Car in Kalkhoven and Forsythe and they were not willing to feed the competition? Wonder just how much of the Chevrolet was still the Cosworth. Don't really follow the IRL too close.

 

[Slideblues]

Well thats a VERY good question

Official statement from Doug Duchardt (Dir GM Racing):

The IRL no longer met our business objectives, We found ourselfs at a crossroad's.

Gene

 

[TimD]

Gene,

Did you deduce anything from my questions? (Other than the O/B SAW record is within reach)

Tim.

 

[Villainder]

Hi Tim,

Im filling in for Gene, he has a suprize for his 3000th post.

Yes he did, looking at the 1745/3 and H7, Was talking to Mark S in the chat too,

Steve V

 

[Jerry Wyss]

This Board is gonna Freeze Up like Canada without Gene,,,Tim D, Ya better

start Speadin' That "Fire" aound a little more.

I cant believe you guy's have a "Endless Summer" down there,,,Man I'm missin'

that sun already.

Question For ya Tim: TT OB,,What "Air cooled" head did ya use?,,What model TT

car engine?

 

[TimD]

Jerry,

I think it was from a 21BRP, blue coloured head. The engine that was used in the TT Mirage 1/8 scale buggy. I used the sleeves from them too in the early days as the stock liners were nickel plated and not chrome plated.

I might still have one of those heads somewhere if you are interested. I'd have to have a look.

Gene / Villainder / whateveryoucallyourself,

You missed my point. Have another try - look at the earlier posts before I asked the q's.

Tim.

 

[Jerry Wyss]

I remember

 

[Villainder]

Tim you have to remember that Gene is from Missouri "The Show Me State" :lol:

Lets see.......Triangle of Stability.........Extreme Revs........... :blink:

Steve V

 

[TomMoorehouse]

timd is after on OB hydro record???

 

[Watercadet]

timd is after on OB hydro record???

74178[/snapback]

​

Ahhhh Tom... you sharp dog... Go Tim D!

Adam

 

[TomMoorehouse]

timd is after on OB hydro record???

74178[/snapback]

​

Ahhhh Tom... you sharp dog... Go Tim D!

Adam

74181[/snapback]

​

just a guess.... i might be wrong???

 

[TimD]

Nah - I am not interested in records personally. I'm just going to state a few things we know and hopefully you can deduce something usefull from it.

1. Speeds are almost the same for O/B tunnels and O/B riggers.

2.The common link between an O/B rigger and a O/B tunnel is the O/B itself....

3. Inboard 20 riggers are doing close to 100mph and we are talking about 60 something for O/B' riggers???

So what are the main reasons for the huge differences in (3)???

I'm thinking it mostly is a balance thing - particularly the weight measured at the prop.

Addressing this in a conventional tunnel is close to impossible. Maybe the whole tunnel concept needs to be looked at the reduce the effect of weight acting on the prop. Gentlemen, start your rule books!

I'm sure there are other reasons too - but I'm not going to all the leg work for you guys! hehehe... Have fun B)

 

[Villainder]

This from tha "Mean Gene"

Yo Timbo,

I have to agree with you on the balance thing, It is hard to compair a hydro setup to tunnel, the weight is further forward on one and all hung out the back on tha other.

I do think a few of the principles involved in one can transfer to the other, But as you said with conventional tunnel design it is limited how far you can go.

Dont want to reinvent the wheel really, Just make some improvements as to top end acceleration. Now what this will be I am totally out of ideas, this last hull is the sum total of what I know and will see how it goes,

Fingers crossed,

Gener

Transcription by yours truely,

Steve V

 

[TomMoorehouse]

Nah - I am not interested in records personally. I'm just going to state a few things we know and hopefully you can deduce something usefull from it.
1. Speeds are almost the same for O/B tunnels and O/B riggers.

2.The common link between an O/B rigger and a O/B tunnel is the O/B itself....

3.  Inboard 20 riggers are doing close to 100mph and we are talking about 60 something for O/B' riggers???

So what are the main reasons for the huge differences in (3)???

I'm thinking it mostly is a balance thing - particularly the weight measured at the prop.

Addressing this in a conventional tunnel is close to impossible. Maybe the whole tunnel concept needs to be looked at the reduce the effect of weight acting on the prop.  Gentlemen, start your rule books!

I'm sure there are other reasons too - but I'm not going to all the leg work for you guys! hehehe... Have fun  B)

74261[/snapback]

​

This goes along exactly with my "what exactly is an outboard" post. the engine on a plate idea I had will move the weight forward a lot. along with better aerodynamics. SO it still remains.... would it be legal?

 

[TimD]

What about insetting the transom so far that the drive dog is level with the rear edges of the sponsons, and using a sponson and tunnel design that runs very flat without a lot of drag?

 

[GTR]

Hi Guys

A hydro initially carries the weight further forward, yes, but so is the lifting element of the sponsons - relatively close to the same point. Carrying some weight on the prop.

I agree it would be interesting to work out how much weight is carried on both the hydro and the tunnel - but the whole purpose of the tunnel is to carry the weight. Far more so thatn any aero effect a hydro experiences. From that viewpoint the weight carried by the prop is somewhat irrelevant.

 

[TimD]

  From that viewpoint the weight carried by the prop is somewhat irrelevant.

74497[/snapback]

​

From the viewpoint that you have it on plane already - yes. However- the weight on the prop has a serious effect on launching and the size of the prop that can be used.

Would an O/B rigger with say a very hot Novarossi pull the same prop as an inboard rigger using a similar engine?

 

[shoboat]

Tim,

The OB Hydro will NOT pull the same propeller as a inboard. We have tried

many different ones. For some reason I think the 1745/3 was one of the best

on my buddies OB Hydro. Tim and GTR, our prop weight on our 21 Hydros is

around 8 ozs. I bet on a OB tunnel or Hydro it is well over a pound. There is

a lot of difference in prop weight which is very important when setting up your

Hydros.

Thanks,

Mark Sholund

 

[TimD]

Mark,

Thanks for proving the point B)

I'll get some dollars off to you tomorrow for the order.

Tim