FoxDB

72chevy, I have a mod 1/2 that the builder extended the very and rudder I believe how you did. When flying when rudder was pushed at cruise speed it deflected about 3 " this made me nervous so I added guy wires from top of horz to vert and this gave a warm fuzy. Just thought I would mention it.

I was preparing for a flight this morning and checked the brakes when the left rudder cable broke. This was not readily visible at preflight. I don't like the way the cable was crimped so tightly around the disc. I plan to put a stainless thimble around the disc to prevent such a tight bend of the cable.

My neighbor is the guy who builds the dual plug 670 heads as well as the exhaust systems. The exhaust system controls the rpm of the engine after the hp peaks with increased rpm the hp drops dramaticly. My 670 hp dyno'd at 92.

I don't know what phase of building or flying your in but FYI I added a manual trim that  just spring loads the controls since my plane was at flying stage. Have been happy with it.

Did not have the egt working that's why I have not flown it again. It has a 72" diameter. Don't remember the static but it would rev up to say 6500 then gradually drop while still at full throttle but that was with the modified 582 pipe. So Mike Hair built a 618 version he was providing for Rotax Rick but I have not flown it yet.

I am wondering what experience 670 drivers have had with this combination?

I recently put a 670 in my KF mod 1. I have been told it is not enough prop for this engine. I have only flown it once but had an exhaust concern. Have not tried it yet since having a new exhaust built (618 style).

Not enough to know about, I get to many projects going. Hope to get back to it before to Long.

I also changed to premixing, partly to insure I always had enough oil and partly weight and C.G.as the engine and exhaust system is heavier. Mike Hair is my neighbor and helped me build the 670. I then helped him with the build of a 720 (670 bored to accept Polaris pistons). I ran my 582 for 700 hours trouble free but was getting concerned about the high time. I also had a leaking oil injection check valve for the latter part of that and thought this is a way to eliminate this problem.

Dave

Are you going with oil injection or premixing.

Sorry nlappos, I see your picture is prior to modification of the exhaust and your plane is an avid. Please disregard my prior comment.

PS Mike developed the 582 pipe modification on my 670 engine

nlappos,

I hope you realize that is not the correct manifold for your 670. If your plane is a Kitfox you will need the shortest version of the Rave engine manifold to keep the elbow from interfering with the cowling.

Kitfox 1, 13600 @ 300fpm Arctic Sparrow mixture control

I believe your tygon tubing is Vinyl Tubing because I have seen the same thing. I now use Urethane tubing from snowmobile shop (blue stuff). Caution never use Urethane tubing in a coolant line the hot coolant degrades it quickly I have seen 2 cases of failure 1 lead to a forced landing!

Well all comments were very good. Now to change the subject slightly. I watched a demo years ago of a super cub doing cross controlled one wheel landings and switching from one wheel to the other. I had to try it which I did first in a C150 just had to keep the nose wheel from touching. I later did it in my Kitfox 1 which was easier. I was showing off (now you know where this is headed) with a rider one day doing this. I herd a scraping noise. The right droop wing tip lost a little fiberglass. DON'T Try this at home. Hey these are toys aren't they!

I had them on my model 1 before I built my bush gear. The only problem I had was a shacking of the puck when it was worn a bit. The only other problem is puck replacement availability.

First off with help from my neighbor (who builds exhaust systems and parts for Rotax Rick) I converted a 670 for my Kitfox. We did not use oil injection. You also need to plug the injection nipples. We just put a dab of solder in each they can also be pinched off.

The engineer issue is close to my heart. I worked as a tooling and equipment designer at Thiokol for 31 years. The operations folks saw me as an engineer. Thou I was was not degreed I worked as an engineer. The biggest issue was being able to understand what was really needed. Yes people are human. But bad mouthing usually comes from not understanding each others point of view.

At least there is a horizontal tube between the cabane mounts. This should help save your longerons.

Hey Joey for what it is worth a Friend and neighbor of mine has the snowmobile stator rewound to have 2 ignition circuits as the 582 does but uses snowmobile CDIs, Triggers and coils. The spark is much hotter and it starts easier. He just put one on a 720 (Big Bored 670). The problem is alot of radio interference and alot of shielding is required. Just a thought as Snowmobile Parts are cheaper.

I am installing a Rotax 670 in my Kitfox 1. It currently has the Arttic Sparrow Mixture control system installed that I was using on the 582. I would like to use it on the 670 but manuals say a different needle jet and needle are to be used. I could change the needle jet but it would be very difficult to change the needle as it is soldered in to allthread. Has anyone tried this and could advise me?

I don't like to ask someone for information so I can do myself that which is part of how they make a living. So does anyone on this list have this information and is willing to share?

Does anyone have a Drawing of the provision 8 case dimensions I could use to machine a 583 or 670 case to accept a "C" Gearbox?

I installed one on my mod 1 Kitfox with an AH and it has worked well. I don,t see a need for DG as GPS works very well for that.

Herman Pahls from the Kitfox list switched from a 532 to a 2200 Jab on his Kitfox model 1 and was disappointed. Switched to a 582 and was much happier. Short field takeoff was the problem due to lower thrust from the smaller prop.

Chris,

I just remembered the rest of the story. I also went with a taller gear and that increases the moment when braking due to the to the increased arm from ground to vertical CG.

Chris,

I moved it forward because I did want to improve ability to hard brake with out nose over. However I did not nose over with the old gear.