Ossi F.1 Tunnel 1st test

[winston]

Winston
James is right, you messure fromt he back edge of the sponson, not the transom.

The CG of my Ossi is at 32% with 500 grams (17.6oz) weight in front. It messures 15.62 inch from the back edge of the sponsons.

Hope this will help you, its difficult to say my CG is at the good point right now, but I think I'm getting close.

Today some nice VooDoo props arrived, so I will do some more testing. Will let you know.

Gr Marc

Hi Marc, So there must be something wrong, my CG is 13`` from the sponson with 1 litter water IV bag in the nose of the Hull, total weight is 9.7 kg = 21.3 lbs

Don't you think so???????? <_< :huh:

~~~`Winston`~~~

Thanks Buddy

~~~`Winston`~~~

Winston

So your CG at this moment is around 28% from the back of the sponsons. What I believe from 1:1 F1 tunnel is the CG from 33% and further forward from back end. Take a look at the picture where the boat is hanging in the crane and you will see where the halters are attachged.

Don't know the complete exact weight of my engine, but I put my radiobox as far as possible in front of the nose.

I know Arian Hendriks with his Ossi was also running with 1000gr of weight in in the nose of the hull, what I ment is that it's not that wrong.

How is your boat running, is it near flip over at high speed. What you can try is to put some more weight in font so you will be at 33% CG, but what comes up must come down to. So if you hit a wave and it will lift the boat up a bit, by the next wave it comes down quicker and the boat will go like a submarine. (that is why 1:1 tunnels will not run with to much swell)

What I know from scale F1 tunnel racing is that the best setup for CG is from 30% / 33% like James sayed.

<a href="http://i11.photobucket.com/albums/a184/rac...38/DSC08116.jpg" target="_blank">http://i11.photobucket.com/albums/a184/rac...38/DSC08116.jpg</a>

<a href="http://i11.photobucket.com/albums/a184/rac...38/DSC08124.jpg" target="_blank">http://i11.photobucket.com/albums/a184/rac...38/DSC08124.jpg</a>

<a href="http://i11.photobucket.com/albums/a184/rac...38/DSC06956.jpg" target="_blank">http://i11.photobucket.com/albums/a184/rac...38/DSC06956.jpg</a>

Gr Marc

Hi Marc, Thanks a lot for your help, so in another word I must have the outboard a little heavy, because I made every thing by the rule, what looks strange to me is that the hull weight 8.3 kg complete but with out the one litter water IV bag in the nose of the Tunnel.

Thank you for your time Marc.

~~~`Winston`~~~

Your picture makes clear that your radiobox is in a good position.

The basic point: make the CG of your tunnel between 30 and 33% from the back end of the sponsons and after that you must test props and engine setup. (engine hight & trim)

I have run my Ossi with a prather 270 with a speed of 54 mph with stock Zenoah 260, (the first 30mph in my early message was not correct) have to do some more testing with 3 blade props.

Gr Marc

The height of my OB "the prop shaft" is one centimeter up from the sponsons. What is your tunnel Height and weight complete with out IV water bag Marc and no Fuel.

Thanks for your time.

~~~`Winston`~~~

Winston

Tunnel weight with out fuel and front ballast is 8.8 KG (19.5 lb) prop height is 11 milimeter up from sponsons.

Gr Marc

 

[winston]

Hey Winston
That looks cool, running good to but sounds like I mis lots of RPM.

Like to show you some pics of my Ossi running this weekend to, I hope you to show a longer vid soon.

Speed at this moment 30mph for a 23lb tunnel.

http://i11.photobucket.com/albums/a184/rac.../Finalcheck.jpg

http://i11.photobucket.com/albums/a184/rac...8/Therewego.jpg

http://i11.photobucket.com/albums/a184/rac...38/Letsrock.jpg

http://s11.photobucket.com/albums/a184/rac...nt=MOV09962.flv

Gr Marc

Hi Marc, If you have a longer video you can put it on the YouTube and saves you all the trouble downloding the file on the web, after all, most files are to big and it dos int allaw you to down loa d.

~~~`Winston`~~~