BBlades - Mirage Plus Norway
06-29-2008, 04:56 AM
#1
Registered
Thread Starter
BBlades - Mirage Plus Norway
Hi!
I trust you are well.
I have done some testing with the props. The boat goes into plane nicely. A little ventilation. Not much. Cruised along in approx. 48-49 mph at 4.000 rpms.
Top speed at 86-87 mph at approx. 7.400 rpms with two people. I need to use max trim, so maybe (if it is possible) to build in more bowlift in the props. What do you think? Then we should have a potential for more speed.
The set up is as before. Propshaft approx 1,2 inch below the bottom. And engines mounted direct to the transom. I tried with 1 inch spacer between the transom and the engine for more setback, but the boat ended up sitting too low with the water coming into the engine splashwell. I also tested with the engines one hole up (0,75 inches up), but the boat was too unstable at WOT running too high. Ideally the engines should have been mounted with 1-2 inches setback, but the boat sits very very low causing a potential for sinking if heavy rain. The boat is only 5,5 feet wide..
Great props!
Cheeers, Toffen G
I trust you are well.
I have done some testing with the props. The boat goes into plane nicely. A little ventilation. Not much. Cruised along in approx. 48-49 mph at 4.000 rpms.
Top speed at 86-87 mph at approx. 7.400 rpms with two people. I need to use max trim, so maybe (if it is possible) to build in more bowlift in the props. What do you think? Then we should have a potential for more speed.
The set up is as before. Propshaft approx 1,2 inch below the bottom. And engines mounted direct to the transom. I tried with 1 inch spacer between the transom and the engine for more setback, but the boat ended up sitting too low with the water coming into the engine splashwell. I also tested with the engines one hole up (0,75 inches up), but the boat was too unstable at WOT running too high. Ideally the engines should have been mounted with 1-2 inches setback, but the boat sits very very low causing a potential for sinking if heavy rain. The boat is only 5,5 feet wide..
Great props!
Cheeers, Toffen G
07-01-2008, 10:36 AM
#2
Offshoreonly Advertiser
Offshoreonly Advertiser
Thanks Toffen. Sorry for the delay in response. Yes we can put more bow lift into the propellers. The issue becomes the rpm levels. As you add rake with cup, there becomes a point that the rpm levels begin to fall also. The decision must be made as to how far to push it before the bow carries higher and the R's drop as well as speed.
Looking at your recipe, yes we have some room for increasing the front carrying ability.. Let us know if and when you might like to do this.
Sorry again for the reponse delay.
Looking at your recipe, yes we have some room for increasing the front carrying ability.. Let us know if and when you might like to do this.
Sorry again for the reponse delay.
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
07-01-2008, 06:22 PM
#3
Registered
Thread Starter
Hi!
Its Toffen again.
I tested the boat again today, and it ran constantly 87 mph at approx. 7.500-7.600 rpms, which is very good. The potential is there.
I still use a lot of positive trim. I will drive over to a great testing fjord tomorrow, and check out further (especially the rpms vs the speed figures). My engine builder (Micheal Werner, 6 times world champion in F1) prefers the engine to run approx. 7400 rpms at WOT.
When do you have time for a rework? If the engines spins 7.600 rpms tomorrow, I suggest more bowlift and an extra cup to bring the engines down to 7.400 rpms.
Cheeers! Toffen G
Its Toffen again.
I tested the boat again today, and it ran constantly 87 mph at approx. 7.500-7.600 rpms, which is very good. The potential is there.
I still use a lot of positive trim. I will drive over to a great testing fjord tomorrow, and check out further (especially the rpms vs the speed figures). My engine builder (Micheal Werner, 6 times world champion in F1) prefers the engine to run approx. 7400 rpms at WOT.
When do you have time for a rework? If the engines spins 7.600 rpms tomorrow, I suggest more bowlift and an extra cup to bring the engines down to 7.400 rpms.
Cheeers! Toffen G
