Air Trap Sponsons

[Charles Perdue]

OK

 

[PHM Racing]

Good Read , howabout some pix of you 67 sponsons Marty

 

[Mark Bullard]

Well I have not borrowed this design from anyone. I have saw the cutouts in the ride pads of offshore cats for some time. Never given them much thought. We were in Evansville 2006 for the Internats and stay for the big races on Sunday. I notice the cutouts on the rear pads of one the boats on the hook going into the water. A light when off and the idea of what I wanted to do came from that. I have seen all kind of tunnel traps myself and tried a few also but never saw a great improvement. The shingles I have been working with have shown the most promise. It has done two things. One it has made the boats run very light on the water or like they are running on ball bearings, two they have stop the spoon problem that everyone was talking about at the time. Twins have a bad problem of falling in holes in rough water what makes it look like they are putting on the brakes in the straighaways and I do believe that it was the spoon principle that was causing this. It shows worse in Twins than single boats because of the weight of the boats and this problem has all but went away. But it has also shown me another problem that has plague me for years. And this was why I always had to run more angle of attack in all of my boats than all of the other boats causing the boats to start getting to loose in rough water. I have follow some things I have saw over the years that I thought were good ideas. I got this from Don Pickert when I got my first twin 20 plus years ago and have done it on all of my boats ever since. This was to have the ride pad wider about 3" or so in front of the trailing edge and tapper back to the width that I wanted for the trailing edge. This was always about a 1/4" on Twins. Here again with this type of bottom made the spoon principle kick in in a differant way by suck the sponson down in the water and making the boat run wet. The only way to correct this was by increasing the AOA as much as 2 degrees more than the 4 degrees I wanted. My first twin I got from Don had these type of sponsons and when I question him he said it was to help the boat at slower speeds to hold it up. Sound good to me and the idea stuck all of these years but remember that was in my early years of boating and I do feel that Don is still the grandfather of the outrigger. The problem did show it's self at that time and the correction was to 1/8" tunnel traps on the bottom the help the boat. On my boats of the pasted the problem was not always the same but I do feel that it was the differant dimenions of the bottoms over the years and sometimes I used tunnel traps to correct it. I have notice that my sport boats have not had that problem because I did not do this on them.

This has all came to light after the last race I went to in Charleston. And all templets for the bottoms of sponsons have been changed for my new boats and the shingles will stay.

 

[Bob Blazer]

What you are hinting at is the Bernoulle principle. Brian and I experminted with this effect on our gas whiplash GV. We experienced problems with the boat sucking down on the straights. I mean it would go from 70mph to 50mph in a heart beat. We went back to the dawing boards and put a step on the bottom and small steps on the sponsons. That fixed the problem. Those steps broke up the surface tension.

I'm reading and learning. Thanks guys.

The Dad -

 

[Bob Blazer]

Any more on this topic? I didn't mean to slow down the discussion. Sorry.

The Dad

 

[Terry Keeley]

I haven't tried air traps or "shingles" yet, but I know for a fact that having the bottoms absolutely flat and sharp can make a huge difference in launchability, ride etc.

I like a 400 grit finish and have started waxing them too. If the way water falls off my car is any indication it has to do "something". :lol:

 

[SayMikey]

I haven't tried air traps or "shingles" yet, but I know for a fact that having the bottoms absolutely flat and sharp can make a huge difference in launchability, ride etc.
I like a 400 grit finish and have started waxing them too. If the way water falls off my car is any indication it has to do "something". :lol:

Here is an attempt by an unlimited

 

[dr gary turner]

Mark and I have had the shingles on my sport 21, Crapshooter 101 hydro and on SGX60 and my SST twin 90's. There was marked inprovement in the launch and getting up on step and the acceleration is greastly improved. The boats also seem to handle the rough water better.

I will atest to Mark's statement on the fact that he did not borrowed the idea. His account is correct because I was at the same Nats, running partner, and we discussed the concept at length.

The tunnel spnsons have been around for a long time. The first that I saw was years ago at a race in New Orleans and the O'Donnell's had a baby blue hydro with the tunnels and many other innovative concepts in the boat. They ran a Picco that was air cooled.

Another amazing boat at that race was a black guy who came all the way from California and he had a bueatiful black twin that he would "rope" start.

I wonder how many folks have seen motors started with a free hand ROPE?

 

[carlnoki]

Doc;

iknow the guy you are talking about with rope starting his twin. HIS name excapes me, but his son's name is Ralph and he races out in the Los Angeles area.

DANG OLD AGE!!!!!!!!!!!!!!!!!!!!

carl

i believe his first name was Jim i could be wrong as usual

 

[Scott Schneider]

Doc;iknow the guy you are talking about with rope starting his twin. HIS name excapes me, but his son's name is Ralph and he races out in the Los Angeles area.

DANG OLD AGE!!!!!!!!!!!!!!!!!!!!

carl

i believe his first name was Jim i could be wrong as usual

Jim & Ralph Henry perhaps ?

 

[El Zorro]

When my Dad started racing in the 70's he started his boats with a leather shoe lace. Steve Ng always started his boats this way until just a few years ago, I think.

Dick Tyndall

 

[carlnoki]

YES!!!!!!!!!!!!!!!!!!!!

Jim and Ralph Henry thats the one

thanks

carl

 

[Marty Davis]

Mark and I have had the shingles on my sport 21, Crapshooter 101 hydro and on SGX60 and my SST twin 90's. There was marked inprovement in the launch and getting up on step and the acceleration is greastly improved. The boats also seem to handle the rough water better.I will atest to Mark's statement on the fact that he did not borrowed the idea. His account is correct because I was at the same Nats, running partner, and we discussed the concept at length.

The tunnel spnsons have been around for a long time. The first that I saw was years ago at a race in New Orleans and the O'Donnell's had a baby blue hydro with the tunnels and many other innovative concepts in the boat. They ran a Picco that was air cooled.

Another amazing boat at that race was a black guy who came all the way from California and he had a bueatiful black twin that he would "rope" start.

I wonder how many folks have seen motors started with a free hand ROPE?

Gary:

His name was Gene Adams, and yes his boats were awesome!

Marty Davis

 

[lohring]

All Mike Bontoft's SAW hydros, from the 3.5cc outboard hudro (81.6 mph) to the GX1 gas rigger (109.2 mph), use air trap sponsons. They were good for a 3 mph speed increase in the 100 mph area. They made the boats track straighter and handle rough water better as well. I'm working on a design for heat racing since the SAW boats trip badly when turned at speed.

Lohring Miller

 

[SayMikey]

All Mike Bontoft's SAW hydros, from the 3.5cc outboard hudro (81.6 mph) to the GX1 gas rigger (109.2 mph), use air trap sponsons. They were good for a 3 mph speed increase in the 100 mph area. They made the boats track straighter and handle rough water better as well. I'm working on a design for heat racing since the SAW boats trip badly when turned at speed.
Lohring Miller

Lohring how about a few pics?

 

[Roger Hooks Jr.]

Doc;iknow the guy you are talking about with rope starting his twin. HIS name excapes me, but his son's name is Ralph and he races out in the Los Angeles area.

DANG OLD AGE!!!!!!!!!!!!!!!!!!!!

carl

i believe his first name was Jim i could be wrong as usual

Jim & Ralph Henry perhaps ?

Yep! That would be Jim and his son Raphy Henry. They kept using the rope until his dad retired from pitting for his son. Jim passed away recently. He was the last of the rope starters as I know it. Everyone that used to do it or knows someone who did remembers that rope in everyone's back pocket and remained in the starter box as a back-up after the electric start for many years. My dad used to rope start. Now we joke about who is going to rope start the boat when we see that the a starter belt is near it's end but no time to change it before the next heat. I tell him he has the experience I was merely a spectator back in them days.

 

[Chris Wood]

i remember watching andy do it at indy yrs ago with what looked like a shoe string lol. on the clock belt broke and he reached in his pocket and got it out. put it on and on the second try fired right off lol.

never seen anything like it and it was cool to see him do it.. never broke a sweat and was so calm lol. don't know how he didn't loose his cool.

chris

 

[Andy Greene]

A lot of the tether video's I have seen , they rope start- looks like a pain in the rear compared to 24v

BTW - You guys are showing you age -lol - KIDDING

GREAT THREAD - please keep going .......

Andy

 

[Mark Bullard]

Well I have roped a boat or two. Not many and only when the belt had broke. I once started a motor with the broken belt. It is a lot like propping a airplane motor. I started flying airplanes before they had starters and never bought a starter until I got into boats in the early 80's.

 

[dr gary turner]

Mark and I have had the shingles on my sport 21, Crapshooter 101 hydro and on SGX60 and my SST twin 90's. There was marked inprovement in the launch and getting up on step and the acceleration is greastly improved. The boats also seem to handle the rough water better.I will atest to Mark's statement on the fact that he did not borrowed the idea. His account is correct because I was at the same Nats, running partner, and we discussed the concept at length.

The tunnel spnsons have been around for a long time. The first that I saw was years ago at a race in New Orleans and the O'Donnell's had a baby blue hydro with the tunnels and many other innovative concepts in the boat. They ran a Picco that was air cooled.

Another amazing boat at that race was a black guy who came all the way from California and he had a bueatiful black twin that he would "rope" start.

I wonder how many folks have seen motors started with a free hand ROPE?

Gary:

His name was Gene Adams, and yes his boats were awesome!

Marty Davis

Those were the good ole days. It is amazing the improvements since that era in radios, servos, hull and material technologies. When we traveled we had to be SOOOOOO careful not to bump the rudder because it would strip the gears in the servo. Gary