niteridder64

Hope to find something at sun&fun this year. I will give nwins. a try thanks.

I have an exp light sport FIB, flying inflatable boat, weightshift cntl and my previous ins co. just bailed out of the market. My broker, O2 powersports ins. told me there is no one out there. I am just looking for liability. Who is writing for seaplanes these days? You can call or email me if you got any leads, thanks. Mike 813 695-5597  mkmoldovan@yahoo.com

OK I get that but w/ everything being the same, wouldn't more hp give me more rpm's and allow me to increase my pitch. I did not get that, I got about 200 more rpm's I did adjust my prop but mainly b/c the builder told me the 670 had a lower max rpm than the 582. I gained a little, barely noticeable, not 1/3 more hp.

Could you explain why. I just changed ratios frm 3 to a 2.62 to spin the prop faster, my tip speed is too low.

I had a 582 w/ 4 blade warpdr. w/ a 3 to 1 but after looking at the prop calculator realized I was spinning it too slowly so just changed to a 2.62. and bought a 670 , haven't worked out all the bugs but it should be a big improvement.

Warp drive has a good website for info. There is also a blue hyperlink to a propeller blade pitch calculator that will help in selecting size of prop and gearbox.https://www.warpdriveprops.com/ Daryl is a good guy to work with.

Honestly after installing the 670 if you told me I still had my 582 I would have believed you. He said 90 hp at 6500 rpm. That is a big jump from 65. Please post your comp I am very curious.Thanks

Never heard of anything like that but good Idea.

Yes I agree hard to find a 670 head w/ dual plugs and Rick did say a big overbore would require the head to be opened up. I looked at y pistons more closely and the tops have a slight rocker to them, not quite domed to help match the head squish band. Does anyone know, if it is important for the entire squish to be close to the same clearance maybe getting slightly larger as it goes toward center.

I cc'd the chamber at 38 and the angle of the squish at 15.2 deg. I agree w/ the poster above(Myself) if I had domed pistons I would be in that range 6-12. now I feel my squish velocity is so low I am getting a week charge in the dome and the outer area starts to burn on the way down not producing much but giving high egt(which I will be installing when I go back together) This is a 670 w/ a 582 head built by Rotax Rick for experimental aircraft, . I will contact him to ask why he picked this piston/head combo. I am just not that familiar w/ the guts of this eng if this is normal. I will call some other aircraft builders and get their opinion.

I had a rotax 670 built for me for use in and exp aircraft. I am lower on power than I thought and low on compression-120- w/ a good known gauge. I checked the squish and it measured .120 w/ a piece of twisted solder parallel w/ the pin up against the cyl wall. After removing the head I saw the squish area is beveled up yet the piston top is flat. the squish is .063 deep into the head and the deck height is .010. So .073 squish but only at the outermost point and gets bigger really fast toward center. My question is, should I have domed pistons in this eng? What is a good squish and cranking compression for a safe stock set up? Thanks.