3.5 Tunnel SAW record

[Jimboat]

Geraghty & Tom - There are indeed quite meaningful relationships to tunnel height, width to performance and dynamic stability. As for your "diffuser effect" - if you mean the "angle of attack" of the aerodynamic "wing" formed in part, by the tunnel roof (often called 'air compression'), then this is defined by the tunnel height/width relationship and the angle of attack of the wing. This also impacts the performance and dynamic stability of the hull significantly. These and several other design/setup parameters can accurately predict the performance of your hull.

Check out the formulae for these relationships in technical articles I've written and "Secrets of Tunnel Boat Design" book.

/Jimboat

 

[zrwhat]

Anbody have any news from the record trials?

Brent

 

[Bob Kensill]

Well,I survived the record trials in Huntsville this past weekend. No records were set. Partly due to the wind,partly due to low attendance. I am still .3 seconds off Tommy Lee's record. My best passes were with my Heat racing setup. 57-59mph all weekend. My best engine is my CMB/MAC hybrid. My Mac throttles better(even with the inboard carb) but was about .2 slower. My best overall prop was a pitched up modified Prather 220. I picked up a secret weapon at this event that I will try later.

 

[Geraghty]

Hey Bob,Like to tell us what that weapon is...

Guess who gave me a call today?

 

[Grimracer]

Tommy was at the event and Rod got a call...Hummm

Bob has a new something...

Tommy, Rod and Bob...Hummm

Come on Bob...we are hot on you tail...tell us about tommys record hull...is it nice?

Grim

 

[Bob Kensill]

Come to Flint Michigan and find out.

 

[Slideblues]

Hey Man post a picture of it.......Please!!!!!!!

Gene

 

[AWaddle322]

Grim,

Have you ever seen one of Tommys boat that was not nice. I think a work of art discribes them better.

Allen

 

[Grimracer]

Allen

I have seen Tommys work but not his Record boat... Your right..work of art is an understatement...

Tommy skills are what all serious boat builders aspire to achieve. Well maybe not all but I can think of one for sure….

Grim

 

[AWaddle322]

He only builds boats one way, All of his wood boats are works or art.

Allen

 

[Bob Kensill]

I plan to run the boat at Flint in May. After that I will post some pics. I am supersticious about taking pics of my boats before running. At last years IMPBA Internats I let them take pics of all my boats, except one, before the race. Guess which one was national champ. As Allen said though,the boat is a work of art.

 

[Tommy Lee]

Hey everyone- I haven't been on here for awhile due to severe eye problems. Thank everyone for the nice words. It has been a great 27 years for me but my driving days are over. I guess I have known for a while but after this past weekend at the record trials I finally admitted to my self that I can no longer see the boats on the course. I may try to stay involved somehow but I do not make a good spectator. I will try to keep posting on this forum as I have a ton of info I would like to share if anyone is interested. I think some quuestions were ask of me so I will try. GRIM- I don't know what you thought you saw on Mitch Harper's boat .It is a typical oval boat with a narrow sponson on the right and a wide sponson on the left and there are no rounded corners anywhere on the bottom. Maybe you can explain what you saw? To the person who said "think how fast it would have gone if he had been on the bouys", anyone who would make that comment probably has never set an oval record. The boat WILL turn on the bouys but due to either H.P. problems or boat design it scrubs off too much speed in a tight turn so it worked better to stay wide and keep the speed up. If you have done the math you know that for every 2ft you go away from the bouys you only add 6ft. to the length of the turn so I feel it is a good trade off. A wider turn with more speed out of the turn will also give you more speed at the other end of the st.way which results in better E.T.'s. My finger is cramping.

 

[Tunnelbill]

Hi Tommy,

Great to hear from you, I wish you the Very Best and would love to hear anything you have to say about outboard. Thanks Bill

 

[Grimracer]

Tommy

Thanks for the years of knowledge and help that you have given to the hobby. We as tunnel racers need to have your input to help us all become better boaters.

Three Cheers for Tommy Lee

Hip Hip..

O yea…Mitchells boat was a 7.5cc hull with mahogany tops. It had a cowl on it that looks as if the cockpit was from a 747..very beautiful.. The cowl was White with red. The bottom of the boat was white and the right sponson was as sharp as a tack, but the left sponson (keelson to bottom sheet) was rounded.. the paint was still in place.. Mitchell said this was how he got it from you..?

Hum…I have an idea…

Kind regards

Mike Zaborowski (grimracer)

 

[Ron Olson]

Bob, what's the date of the Flint record trials and how do I find Thread Lake? I'd probably be going up the same way that you would.

We gotta meet up again so that you can pick on me some more! We sure had fun at the Internats last year!

 

[Tommy Lee]

Tunnel Bill-Thanks, I will try to post things when I can. I have a lot of info on aero stuff if anyone cares. Someone said on here that working on aero drag seemed like a good idea, that is absolutely a good idea. That is probably the only place you are going to see any gains in performance. GrimRacer, were you sniffing CA that day, (just kidding)-The boat you described is the boat I remember but the rottom is birch ply finished natural. The cowl is the only thing white. Oh well maybe my mind is worse than my eyes. I really enjoyed that boat. It was actually built for the older water cooled engine but about the time I finished it the Pro motor came out so you can guess what went on the back. I had a target speed of 48MPH with the old engine but I have actually seen 54MPH in race trim with the Pro motor. Oh well I guess we are kinda off the subject of st.way boats huh.

 

[Grimracer]

Tommy

Yea...crap i can not remember...now that i think about it...im not sure.. :lol:

You did not warn me that the brain goes before the eyes...now i have a toasted memory to go with bad left eye... :blink:

The boat did have a K+B pro motor... Must be it... it sure ran nice..

Grim

 

[MikeP]

Just wanted to jump in here and say thanks to all good input on Tunnel hulls. My new understanding of the "Bernoulli principle" has made a great improvement with my JD 30. It used to do some strange things that I didn't understand and struggled with adjustments in the wrong areas. Not so strange now it was doing exactly what it was supposed to do. With the addition of the correct size and correct location of stumble blocks I was able to fine tune the hull and my driving to get a perfectly handling boat for my own personal needs.

Mike

 

[Ron Zaker Jr]

Hello Mr Lee.

I read you have some "aero" information and I am VERY interested in learning what your findings were.Any input on this topic would be awesome,thanks.

Ron Zaker Jr

 

[shoboat]

Tommy Lee,

I would be VERY INTERESTED since it was me who posted that in the first

place. Aero & Drag are going to be the BIGGEST PROBLEMS for us to race

at higher speeds consistantly anyways.

Hope you keep posting for us. We sure would like to read your input.

Thanks,

Mark Sholund