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rustnrot
06-09-2005, 08:40 AM
I have virtually no experience with "outdrives" being an inboard/ v-drive fan. That said, I am considering the following projects with regards to the supercharged rotary engines in this thread.

http://www.donzi.net/forums/showthread.php?t=39965

1. A Wynn-Mill replica boat construction
2. A baby 14 (nope, no hull but wish I did)
3. A 16 classic (ditto but find-able)

That said, these engines can be connected to an alpha drive (the inboard transmission is removed and an adapter installed). I would not want just any 'ol alpha though. Is there any alphas that have what I would call a "quickie" lower end? Or whatever. You guys know what I mean. And the lighter in weight the better.

MOP
06-09-2005, 09:16 AM
Tom just my thought on this, yes you can shop an SS Alpha drive nice short drive with a nice lower worth some extra speed, but I feel parts are a bit of an issue. You may want to explore raising the X dimension and putting a nose cone on a standard late Alpha to achieve the same goal, I think the late Alpha is better then most think we have a ton on fairly heavy cruisers in or yard. What RPM does the rotary have to spin up to make its rated power, for some reason I thought they were high winders. Out drives do not seem to like ruuning over 5K and maintain reliabilty, though there are quite a few of the fellows getting away with it but for how long.

Phil

Woodsy
06-09-2005, 09:17 AM
Rust...

Your going to be looking for an Alpha SS.... kinda hard to find, but doable. My only concern would be the RPM's you will be spinning. You will definitely need a transmission to reduce the crankshaft RPM. If I remember correctly the rotary's spin at about 7000 RPM or so.... The harmonics alone at that RPM will tear apart an Alpha... probably rip apart a Bravo too.

Now maybe an Arneson.... HMMMMM

Woodsy Von Outboard

MOP
06-09-2005, 09:46 AM
Dave was just off doing a search they seem to make their peak HP up at 8,000, Tom use the transmission to feed the drive. Use the tranny for shifting and leave tha drive in gear constantly adding reliability, a 1.5 box should get you in the ball park. What is the current ratio of what is on it now, another plus is the whole package is so light you are not sacrificing much by using the tranny.

Phil

Lenny
06-09-2005, 09:50 AM
originally posted by Rust'nRot
A Wynn-Mill replica boat construction

hmmmm, we should talk ;)

Rootsy
06-09-2005, 10:04 AM
Dave was just off doing a search they seem to make their peak HP up at 8,000, Tom use the transmission to feed the drive. Use the tranny for shifting and leave tha drive in gear constantly adding reliability, a 1.5 box should get you in the ball park. What is the current ratio of what is on it now, another plus is the whole package is so light you are not sacrificing much by using the tranny.

Phil

ummmm no offense but spinning an alpha, locked in forward, backwards is not gonna work too well.. the clutch dog on the propshaft would ride up the ramp of the dog in the forward gear and you;d just hear clickity click click click...


an alpha "quickie" would be an alpha SS, 3 inches shorter than an alpha... not the easiest to find, a bit pricy and if you plan to run any kinda HP or rpm through em they need some geartrain updating... not to mention the low water pickups on top of the nosecone really love sucking weeds..

J

rustnrot
06-09-2005, 11:29 AM
Needs 6500 rpm sustained, 7000 rpm intermittent. When using in inboard app typically use 1.5:1 trans on these. The ZF trans has a special high speed pump to take the rpms (pump was developed for the defunct Toyota Lexus DOHC motor for their skiboats). Might just go inboard or v drive to eliminate the extra hassle..........especially if the Wynn Mill hull ends up being a rear seater with the engine in front (gentleman's racer style). Can you say exposed rear rudder ala' yesyoucan's 16 v-drive? Mahogany planked over plywood construction, love that full barrel stern......

If I do the Wynn-Mill (thanks George for the plans) I will be using BobCADCAM to make the parts and my shopbot CNC router to cut them. I may shrink it a little make it a 16 footer not sure yet.......

Anybody want a "frame kit"?

MOP
06-09-2005, 10:14 PM
Qoute:
ummmm no offense but spinning an alpha, locked in forward, backwards is not gonna work too well.. the clutch dog on the propshaft would ride up the ramp of the dog in the forward gear and you;d just hear clickity click click click...

Why would it run backwards, the rotation of the rotary is the same as any standard auto engine. There is an RX7 running around here with of all things a V6 turbo Honda in it it is suppose to make well over 400HP, it is hooked to the Mazda manual box. I would doubt they would bother to reverse the rotaion for a marine app. Using a marine tranny also does not reverse the rotation so the Alpha should be quite happy.

Phil

MOP
06-09-2005, 10:22 PM
Tommy you may just get away with the engine forward being as the engine package is so light. I know it don't work well with an Iron block saw it done in a 20 Bertram 350 staright shaft ran like crap and bow steered.

Rootsy
06-10-2005, 06:38 AM
Qoute:
ummmm no offense but spinning an alpha, locked in forward, backwards is not gonna work too well.. the clutch dog on the propshaft would ride up the ramp of the dog in the forward gear and you;d just hear clickity click click click...

Why would it run backwards, the rotation of the rotary is the same as any standard auto engine. There is an RX7 running around here with of all things a V6 turbo Honda in it it is suppose to make well over 400HP, it is hooked to the Mazda manual box. I would doubt they would bother to reverse the rotaion for a marine app. Using a marine tranny also does not reverse the rotation so the Alpha should be quite happy.

Phil


Phil,

maybe i read it incorrectly but what i gathered was that you'd use the tranny sandwiched between the motor and the sterndrive to reverse directions (forward and reverse) and leave the alpha locked in forward gear... am i correct? If so... then my statement stands...

remember, in the bottom of an alpha, you have the pinion, forward and reverse gears in constant mesh, spinning at all times when the engine is running... the clutch dog dictates which direction the propshaft spins, and which gear is loaded...

JR - where's my reading glasses...

gcarter
06-10-2005, 06:45 AM
I kind of like the idea of a tranny. You could use it for additional gear reduction, AND you could have the Alpha stationary by putting the tranny in neutral!
You could just lock out reverse on the tranny, and use the Alpha for direction selection.
Think about this, use neutral on the tranny to make the gear selection on the Alpha, then put the tranny in forward and eliminate all those awful "CLUNKS"!!

rustnrot
06-10-2005, 08:13 AM
For the record the rotation of the rotary is the same as a standard V8, counterclockwise from the ass end. Also interestingly, the ZF trans on it is a full reversing, meaning you can run either way at full power and therefore have a selection of RH and LH props for whatever reason(s).

MOP
06-10-2005, 07:17 PM
maybe i read it incorrectly but what i gathered was that you'd use the tranny sandwiched between the motor and the sterndrive to reverse directions (forward and reverse) and leave the alpha locked in forward gear... am i correct? If so... then my statement stands...

I knew what I was trying to say thankfully George straightened it out, use the Alpha to shift and the tranny for its reduction. Jamie is correct all bottom shifters rachet if turned backward or if the throttle is chopped at speed that is the reason they don't roll the boat on its ear like a Bravo or Volvo when the throttle is chopped.

Mercrewser
06-14-2005, 09:50 AM
http://www.xtremerotaries.com/main2/Quicksilver.htm