Is there way to measure prop rake? What kind if props you are using with runabouts?
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Is there way to measure prop rake? What kind if props you are using with runabouts?
Back in business with long haul. Still porpoising when I can't get it to speed enough. This setup needs just right weather or it not get enough speed. So, if I get more power, then it maybe goes well...
Upper crank pin (cyl.1) has 1 mm offset on lower weight. Something is happened, I dont know what.
All other pin ends are even with weight surface. Distance between weights is 16 mm not 15 mm which...
PhpBB or Simple machines forum (SMF). Both free.
This forum softaware needs fixing and updating. I see errors everytime when posting or uploading.
What size that chamber needs to be? Is there some formula to calculate it?
I'm shaping and painting my gear case. Again and again...
Now I don't like top of the bullet curved shape. (horizontally, when looking from the side)
Look's like it want to dive..
What are you...
It weights about 55-60 kg without engine and tank.
Bottom is 9mm okoume (back), front bottom and chines 6mm okoume.
Here is some building pics
Same prop, same settings and lot of driving today. Here was windy and quite rough water today. I noticed on rough water that so called prop walk thing, not much just like little warnings.. Boat turn...
I put dewald prop back and 37mm below, 3mm tuck. 58 mph @ 6300-6400 rpm
It goes faster when prop is deeper.. :eek:
It start to slip at 30mm shaft depth, I got more rpm's but speed was 50-51 mph.
35mm and 2-3mm tuck, 55 mph @ 5900 rpm. 45+ mph no porpoising and it is very fun to drive, it's going like train....
New prop ron hill cleaver 7x12, shaft 35mm below and paraller. No porpoising at all, 55 mph @ 6000-6100 rpm. Best prop so far..
What kind of type prop works best?
I have done lot of testing.. I found that best setup is shaft paraller and 18mm below. Now I can control it by moving my weight.
Top speed is only 51-52 mph @ 6400-6500 rpm, dewald prop.
Same...
Dewald actually is 7". Few pics, dewald on right.
Yes, settings are set to correct. I heard it from engine sounds that its slips and revs go up.. also lower speed reading is what it should be.
Dewald prop back, 22mm below, 6mm tuck. There was little weather change, winds now 2-3 m/s. Now it works well, no porpoising but speed was only 54 mph @ around 8000 rpm. On wetback this prop 63-64...
Ron hill cleaver 22mm below, 6mm tuck -> 49 mph @ 8200-8400 rpm
It was very hard to get plane.. no porpoising and turns well.
WTB: proper prop :rolleyes:
Tiny tach is new commercial model. It freezed yesterday. I didnt know that reset button has to be press that long, i'll try again, thanks!
Engine kick in is measured with level against bottom and...
Tiny tach wont work anymore, its stuck to 1850.. so I dont know rpm.
First 2 blade: 6 5/8, 12-14 1/2, second 6 1/2 12-13 5/8, both cupped thats why pitch range.
Speed was only 50-55 mph max. They...
Few pictures
Yes, almost there :) I just tried two, two blade prop and porpoising was totally gone around 40-50 mph.
I think those should be run deeper than 3/4, because engine was screaming and there was huge...
20mm below and little bit negative trim. It porpoise less than yesterday but still too much..
4 min. video
http://youtu.be/pGfsdnRPbGI
Thank you all. I try 3/4 shaft depth next.
Do you use some non-stock thrust brackets on yamatos?
I dont have that trim tool.
Last 30" is dead flat, then it start to break "v", just like plans show. I found hydroracer.net thread where they mention 1/8-1/4 tuck. I assume that means negative trim but how it is measured? 1/8...
First test drive done. Shaft is paraller and 35mm below.
Boat porpoising very much (bow up and down). When moving my weight to forward it helps little bit but not much.
What causes this? Prop, trim...
Point of balance is 29,8 inch from rear :)
Next question is yamato 302 trim angle. With stock adjustment system I cant get it even paraller.. It is negative with max. setting.
What is good angle...
This is good info, thanks. Is it center or maybe offset left?
I have boat almost ready and it is still in my garage on the table.
Painting, varnishing and rigging is not done yet.
Plans call 9"×3" center fin but theres nothing about that where it should be, I need advice for that.
If I dont find just that size fin, is it better to use little smaller or bigger?
Thanks :)
Yes, top seal for the gear foot. It's taken out 6 months ago and I can't remember which way it was.
Which way it should be? I don't remember anymore :o