The Boat Design & Boatbuilding Site
Twin Jet Boat Build
- Thread starter Sms986
- Start date
BlueBell
. . . _ _ _ . . . _ _ _
- Joined
- May 7, 2017
- Messages
- 3,426
- Reaction score
- 1,308
- Location
- Victoria BC Canada
I had an RZ350 Yamaha bike for seven years.
Rebuilt the engine the second day I had it.
New reeds and pipes.
Ridiculously fast and light.
I can't believe I survived.
What's your thesis on?
Thing about custom jet installs is getting it too work optimally.
The smallest little thing can set them off.
Are they indeed Hamilton jets?
But this project is a recipe for FUN!
Mr Efficiency
Senior Member
- Joined
- Oct 17, 2010
- Messages
- 10,374
- Reaction score
- 1,051
- Location
- Australia
Sounds like some women, mercifully few, of course !
My thesis is a on separation control via ground effects for road vehicles (CFD).
I'm not too worried about optimal performance, good performance will be good enough for me!
No, they are not Hamilton jets. They are the stock yamaha gp1200 jets
I'm not too worried about optimal performance, good performance will be good enough for me!
No, they are not Hamilton jets. They are the stock yamaha gp1200 jets
BlueBell
. . . _ _ _ . . . _ _ _
- Joined
- May 7, 2017
- Messages
- 3,426
- Reaction score
- 1,308
- Location
- Victoria BC Canada
With such high jet losses to begin with (up to 50%), a misplaced anything could lose you another 40% and your going nowhere fast.
I'm not referring to worrying or even concern about efficiency, just trying to keep it from being a dog and waste of money and time.
Replicate to original instal configuration and hope for the best.
I guess you are familiar with the changes this year in F1 racing regarding ground effects.
They are essentially back on in an effort to clean-up dirty air for the following car.
I'm not referring to worrying or even concern about efficiency, just trying to keep it from being a dog and waste of money and time.
Replicate to original instal configuration and hope for the best.
I guess you are familiar with the changes this year in F1 racing regarding ground effects.
They are essentially back on in an effort to clean-up dirty air for the following car.
Lol, it sounds like you are an Aero guy. I'm still an Aero "kid." I also honestly don't follow the F1 as much as a lot of fellow students do. I am much more interested in passenger cars and such (and boats). I actually wanted to be an IC engine guy but certain people who I will not name here are making the IC engine dream less practical.
I planned on doing some CFD on this hull (basic RANS is all I am really comfortable with at the moment) to see how these will do. I may publish a paper on it. If I do, I'll get much better insight on the performance. May be able to make my own design. But nonetheless, nothing will be cut in stone until I run some simulations. Possibly a comp between the ski hill and the boat hull. I do think these will work fine though, as the pumps are flush mounted on the bottom of the ski with no dip or spoon fore the intake grate.
I planned on doing some CFD on this hull (basic RANS is all I am really comfortable with at the moment) to see how these will do. I may publish a paper on it. If I do, I'll get much better insight on the performance. May be able to make my own design. But nonetheless, nothing will be cut in stone until I run some simulations. Possibly a comp between the ski hill and the boat hull. I do think these will work fine though, as the pumps are flush mounted on the bottom of the ski with no dip or spoon fore the intake grate.
BlueBell
. . . _ _ _ . . . _ _ _
- Joined
- May 7, 2017
- Messages
- 3,426
- Reaction score
- 1,308
- Location
- Victoria BC Canada
You may get a kick out of this:
I put an air dam made out of a strip of old conveyer belt on my Datsun 510.
It hung straight down and straight across from a pair of 2x4's bolted to the bumper mounts.
It was an ice racing car but I drove it for transportation. I was young.
The dam came down to within two inches of the road.
Didn't go any faster (95MPH in third or fourth gear, didn't matter),
but the ride stability was astonishing, felt like a 2-ton Cadillac.
Thanks for indulging the thread drift and my apologies.
I put an air dam made out of a strip of old conveyer belt on my Datsun 510.
It hung straight down and straight across from a pair of 2x4's bolted to the bumper mounts.
It was an ice racing car but I drove it for transportation. I was young.
The dam came down to within two inches of the road.
Didn't go any faster (95MPH in third or fourth gear, didn't matter),
but the ride stability was astonishing, felt like a 2-ton Cadillac.
Thanks for indulging the thread drift and my apologies.
That is awesome haha.
I always get a kick out of the tuners with huge wings that create 10x more drag and will never get their cars fast enough to see the beneficial downforce (on a front wheel drive car anyway lol)
I always get a kick out of the tuners with huge wings that create 10x more drag and will never get their cars fast enough to see the beneficial downforce (on a front wheel drive car anyway lol)
Unfortunately, the thesis is not yet done. I had some issues with the CFD software that were making some wild results and I just traced down the source and got it fixed over the weekend. Now I have to redo my mesh sensitivity study (yay)
Regarding the boat, the project is basically on hold until I can meet with the hull fabricators to go over the design in detail.
I'm also looking for a more sturdy water intake assembly than the factory Yamaha one, and on top of that I found that one of the two engines I bought had a hole in the bottom of the case.
Regarding the boat, the project is basically on hold until I can meet with the hull fabricators to go over the design in detail.
I'm also looking for a more sturdy water intake assembly than the factory Yamaha one, and on top of that I found that one of the two engines I bought had a hole in the bottom of the case.
BlueBell
. . . _ _ _ . . . _ _ _
- Joined
- May 7, 2017
- Messages
- 3,426
- Reaction score
- 1,308
- Location
- Victoria BC Canada
Huh.
Well, that'll slow things down.
How about starting out with just one jet in the centre?
You could test the new style intake assembly, if it works,
twin the install.
Or not.
Standing-by...
Well, that'll slow things down.
How about starting out with just one jet in the centre?
You could test the new style intake assembly, if it works,
twin the install.
Or not.
Standing-by...
I actually got in touch with the guy who builds intakes just now. So that's under way. He's sending me some pictures and dimensions now. Also, the $1500 per pump was in canadian dollars...so I just knocked off $700ish from my original estimation!
The problem with testing with only a single jet is that I would have to taper the keel so that it is flat (horizontal) in the middle at the transom for a single jet. With two jets, I can have the 8 degree keel go all the way back to the transom. If I would do that I would need to have the hull overhauled after testing with one jet-if even possible.
Rebuilding the engine is no task. It would take a day start to finish, if that. The engine issue is more of frustration than a hinderance.
People buy something, break it, then get upset that it's lost almost all value because they broke it.
So, instead of accepting the loss, they try to sell it off to some unsuspecting sucker (me) and get all of their money back, passing along their rightful losses to someone else.
In my opinion that should constitute jail time. It's such a petty little crime. Selling something "As is" should conform with "As advertised."
The problem with testing with only a single jet is that I would have to taper the keel so that it is flat (horizontal) in the middle at the transom for a single jet. With two jets, I can have the 8 degree keel go all the way back to the transom. If I would do that I would need to have the hull overhauled after testing with one jet-if even possible.
Rebuilding the engine is no task. It would take a day start to finish, if that. The engine issue is more of frustration than a hinderance.
People buy something, break it, then get upset that it's lost almost all value because they broke it.
So, instead of accepting the loss, they try to sell it off to some unsuspecting sucker (me) and get all of their money back, passing along their rightful losses to someone else.
In my opinion that should constitute jail time. It's such a petty little crime. Selling something "As is" should conform with "As advertised."
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.
When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.
Advertisement: