Bad luck streak in dancing school.

[Brent_Brown]

I got my rotax 670 flying today, but bad things happen. one of the EGTs came out of the pipe damaged my $600 powerfin prop, that only had an hour on it. only one blade got hit so it is not to bad I guess. I didn't feel it or hear it come off. I will post a photo, I hope you will be able to see it.

FYI the gyro is way fast. or the ASI is off but from the my landing speeds and the wind blast. I say it is working. It hit 80 mph like now. When you get over 5000 RPM she is on the pipe. I plan to cut off 25 pound. No not my head. and make it a one seater.

 

[Timchick]

What kind of gyro are you flying?

 

[scottessex]

Ow! Please post pictures and specs, I am very interested in your 670 conversion and how it works out.

 

[Brent_Brown]

I am flying a one of a kind two place I made. Has a parsons twin mast, drop keel, my tall tail, Rans S12 main geag, jazz mope head front forks, wheel and brake combo. Rotax 670 100 hp with a 3.47 ebox, 74" F type powerfin. I have the prop set at 6000 rpm on the ground so 80 HP is about all it has now.

I tested the motor to get it broke in and all, just under one hour on it with the same EGTs. I ever had them off. I ever had one come off before but things happen. here is the y pipe and prop blade.

 

[Brent_Brown]

If this was a warp drive I think it would be fixable to fly again, but this thig is lucky to made it home. I hope it happened after I got on the ground. I have a ESI for reading the temps. They both worked fine on climbout and then I was looking away and at the airspeed more after that. I was only in the air 1/2 lap around the runway. I was going to ajust for trim and fly again but that all is on hold.
Back to the twinstarr for now until the new prop blade get hear without the wife seeing it.

 

[dragonflyerthom]

Brent it would probably be a good idea to wire wrap the EGTs to avoid it happening again. Which it probably won't.
Can you post some pics of the Gyro. Very interesting.

Thom

 

[gyromike]

Brent,

How easy was it to mount the gearbox on the 670?

 

[scottessex]

Mike,
I think that it requires the crank end cut shorter and some kind of adaptor for the rubber donut on the gearbox.

 

[gyromike]

Scott,

Is the engine case already setup with the mounting bosses?

Somebody mentioned to me that it wasn't too difficult, but I can't remember who.

 

[Brent_Brown]

It is difficult. I got mine from R&D who I don't think make the convertions anymore. He has jigs to mill and tread the case for the gearbox.The crank is cut 3/8 shorter off the PTO and the part that fits to it from the gear box is cut to fit the tapper of the crank, it is not the same.

You still have to use a 1/8 spacer plate to fit the gear box to the case. but I cut 1/6 off the each side of the triangle thing that the donut bolts too. This brings the gearbox right to the case so no spacer plate is needed.

Not all 670s will work only 2 or 3 years. Like 1992,3,4. They have the same case, as the 618 only the gearbox holes are not threaded and surfaced this is what Rob would do to it. If he will do it for you this is the only thing I would let him do for you. Get the case done and then you or a Scott Essex does the other parts. Why? This is why. When I ask him for torque spec on some things he said they us a impact. I was like what the hell. So FYI.

 

[Brent_Brown]

670 tail and gearbox

 

[Rehan K.Janjua]

Hello Brent.

Very nice 670, looks real neat.

Just avoid those spirals on the EGT probes. Re route them and rap the extra length some where safe.

Those twin H/S are awesome.
Always had thoughts to have twin H/S on my A/C 582.
One with full flying tail and one on the keel. Both could be the same A/C H/ Stubs.

Your thoughts are welcome.
Best wishes. Rehan

 

[Brent_Brown]

IF I just go to a tractor this would not eat props stil bad but not as.
Twin HS work great this gyro is flying on rails.

When I convert it to a single place I need to get the motor up some the way it is now the tail wheel is to low so not much rock back to get the blades up to speed. If I get the tubing this week I will take this one part and show the changes.

 

[Cobra Doc]

Just an observation, but it looks like the probe nut is drilled for safety wire. It could be just a trick of the light. Something I learned from the first A&P I ever worked with: "If it's long enough to reach the prop, it will." That pretty much works for all the turning and spinning components.

 

[Brent_Brown]

The prob never hit the prop the nut did. no drilled holes.

 

[Cobra Doc]

I would drill them and safety wire them. That's just me. I get a little anal about aircraft and motorcycle parts. Too much time in helicopters and on a big single I suppose.