Tunnelstuff in Norway

Intlwaters

Help Support Intlwaters:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Had to test a new prototype of silencer for the Salisbury pipe, it made a big difference, but still a little loud.
 

Attachments

  • 5B3EDF90-46BE-4F0C-87FE-8215636E46DB.jpeg
    5B3EDF90-46BE-4F0C-87FE-8215636E46DB.jpeg
    1.6 MB · Views: 308
  • 31E13A13-4DF4-45AA-9FBE-3D589E8EEAC7.jpeg
    31E13A13-4DF4-45AA-9FBE-3D589E8EEAC7.jpeg
    1.9 MB · Views: 311
  • DF4FEC4D-C84C-4B36-9985-7C5390C65186.jpeg
    DF4FEC4D-C84C-4B36-9985-7C5390C65186.jpeg
    1.8 MB · Views: 305
That ratio takes 30k rpm down to just over 20k. I thought I once read that 20k was the best efficiency for a prop, but I can't remember where... keep us posted!
You are right, most props have very high slip percentage on high rpm. I experienced that when I was deep into eletric tunnels. for the Octura X series the slip increase drastically when you pass 30K rpm. Even from 25K the slip starts to increase.
I`m now reading close to 38K rpm on the engine. Will shorten the header a little bit to see if I can reach maximum rpm around 42K.
I have allready enough speed, and the acceleration is fantastic, so it will just be a bonus with some extra rpm`s.

Also for the NR .46 I think gear will be a good solution, they work much better with a little less load and high rpm.
Disadvantage is the extra weight you have to carry on the transom...
 
Hi:
Yes, powertrim is very effective. However, to use it properly in a race you will need to be 100% on target when trimming in before a turn.
If you wanna use it for finding «the sweet spot» while testing it is very effective, boat is responding immediately exactly like the fullsize. Give it a try
I'm still trying to make a system similar to yours, thank you.
If you have more pictures of your model, I am grateful to posted them here already.
Some time ago, I had a car accident and I´m in rehab... When I´m better, I'll start building and posted here.
Thanks for all.
 
Hi:

I'm still trying to make a system similar to yours, thank you.
If you have more pictures of your model, I am grateful to posted them here already.
Some time ago, I had a car accident and I´m in rehab... When I´m better, I'll start building and posted here.
Thanks for all.
Don`t think I have more pics than you can find in post #59 https://www.intlwaters.com/threads/tunnelstuff-in-norway.72995/page-3#post-712547
It`s been quit some time since that boat was wet as there is new stuff and ideas coming up constantly...
At the moment I`m putting my effort into gearboxes.
Wish you a fast recovery.
 
Hi,
here in Europe the geard drive is very comon used. In FSR duration they run up to 90 size engine with gear. They use only a very small gear ratio of 1,2 - 1,3 : 1 , so the engine has a little moore punch out of the corner.
The smaller engine go with higher gear ratio 2 : 1 and higher. Reason is to drive the bigger propeller dia that has less slip and better acceleration and pushing performance in and out of the corner, not for higher top speed.
Very nice drive with the geared outborder setup.

Happy Amps Christian
 
Have you tried a small diameter carby? I have a KRE 10mm which is VERY quiet compared to the 11mm orlic.

LMK if you want to try it? No proper testing to compare performance sorry
 
Got some time to assemble the .28
Gonna be interesting to see if there is something in it
 

Attachments

  • B49B8213-3393-4A3C-A31D-27A193BAFB52.jpeg
    B49B8213-3393-4A3C-A31D-27A193BAFB52.jpeg
    1.3 MB · Views: 234
  • 776E0EA9-A9FB-4A74-AFFD-FEAF408698FD.jpeg
    776E0EA9-A9FB-4A74-AFFD-FEAF408698FD.jpeg
    810.6 KB · Views: 239
  • 39BBB0A8-65B6-4033-A064-712F22CB7FFD.jpeg
    39BBB0A8-65B6-4033-A064-712F22CB7FFD.jpeg
    1.1 MB · Views: 250
  • 92FEC777-3801-4675-91A0-C671E6709ABD.jpeg
    92FEC777-3801-4675-91A0-C671E6709ABD.jpeg
    1.1 MB · Views: 231
I found a sufficient hull for the NR .28
Not many hours left before I can do a test run
 

Attachments

  • 7475FD8F-055E-4B9C-A8F0-5107D3193584.jpeg
    7475FD8F-055E-4B9C-A8F0-5107D3193584.jpeg
    3.3 MB · Views: 211
  • 6952EA4D-0C0F-46BE-BA83-0D223171B8B9.jpeg
    6952EA4D-0C0F-46BE-BA83-0D223171B8B9.jpeg
    3.3 MB · Views: 206
It has been quit a long time since I have shared any news. While the water is solid I will try to have a .12 tunnel finished for testing next year.
It will be powered by OS Speed T1203 in a gearbox setup. OS 18TZ will be an option.
 

Attachments

  • 3DB0A62D-053F-423F-B082-D5DDACC71521.jpeg
    3DB0A62D-053F-423F-B082-D5DDACC71521.jpeg
    95 KB · Views: 184
  • A562AD33-A873-4CA8-BA7D-03083117D6DC.jpeg
    A562AD33-A873-4CA8-BA7D-03083117D6DC.jpeg
    108.7 KB · Views: 190
  • 1945CF0A-A115-4865-B68B-1134762A103A.jpeg
    1945CF0A-A115-4865-B68B-1134762A103A.jpeg
    87.7 KB · Views: 190
  • 9E9F3F4F-5FF1-4197-AD16-4CD3CC9F6645.jpeg
    9E9F3F4F-5FF1-4197-AD16-4CD3CC9F6645.jpeg
    97.9 KB · Views: 179
  • 7966A720-D762-4F2C-8525-E3F94ECD1620.jpeg
    7966A720-D762-4F2C-8525-E3F94ECD1620.jpeg
    98 KB · Views: 186
What hull will you use for a .12? On an OS lower?

Those gear drives look VERY nice!

Did you ever try a small carby (10mm) on the Nova 46? That reduced the noise ALOT on my outboard, would give good bottom end also. With some tuning it could work well for you IMO
 
Back
Top