Dual STI build log

[Shadowrider]

She is safe in the hangar! First flight went well. I climbed it out steep. Data log shows 55indicated climbing at 2430 fpm. Was busy working on it all day trying to get prop balanced. NR props do not like to balance. I will post some pictures later when I can.

[PaulSS]

Congratulations, Dustin. Have a big like for your efforts

Many happy future flights.

[aviator79]

I've been waiting to to hear done good news. Congrats!

[Kitfox Pilot]

Congratulations. I've been looking forward to seeing your first flight.

[Shadowrider]

Thanks guys!

Okay here is the down and dirty. CHTs and oil temps are looking good. In fact I think I may have too much cooling..............maybe? I guess that is better than not enough. On the first flight oil temps only reached 130F and CHTs only reached 175f. So far she is running cool. Of course OAT was 60f. Intake temps where 120f with a max manifold pressure of 49" momentarily. I then pulled the power back to 40" for the climb out. I am going to adjust boost in the ECU. Egts had a split of 75F split between #1 cylinder and #4 cylinder. Not a real big deal but nice thing with this ECU is you can add or subtract fuel trim to get them closer. I am going to add some fuel to cylinder #4, which from what I understand is normal to run hotter in the rotax. Bad news is I found a crack in my muffler where the down pipe bracket is mounted. I have been concerned from day one that the stainless is going to fatigue and crack because its a little thin walled. I contacted Edge and they are in the process of a re-design to address the issue. They will be sending out new mufflers because when they went from 1.5' downpipe to the 2" downpipe fatigue cracks have been showing up. In the meantime I have got it welded up and added some gussets to keep it from cracking again. Hopefully tomorrow I can get the repaired muffler back on and finish balancing my prop. If everything goes well I am hoping to take it back up. When I stalled it first flight I did it with no flaps and power to idle. It buffeted at 47IAS.(MPH) I am going to start adding flaps and checking flight controls with flaps. I still have lots to do on the build. Stall fences still need to be built. Wing cuffs need to be built, its windy without them. Install VGs at some point also. Then we need to get #2 finished up now that I am pretty sure our cooling is going to be sufficient.



Gussets are only welded on one side to help keep from heat warping pipe and that is anti seize on the inside to help slide in the down pipe.

[aviator79]

It's impressive that you're running so cool with that firebreather up front. Do you have an oil thermostat? IIRC, you installed a coolant/oil heat exchanger. The oil thermostat might bring up both your oil and CHT. I bought one from a race supply with a higher setpoint than the one sold most often for Rotax (205 F), and have had great luck with it. Oil temps are almost always in the 190-210 F range. I guess you could also consider taking out the heat exchanger. Right now the indication is that it's doing its job too well.

[Shadowrider]

Brian I am not running a thermostat as I figured I would be running into heating issues. I think the biggest thing is by dropping the lip and giving more exit air, its really doing its job. The heat exchanger was to help bring down the oil temps as I figured they would be running hot. It should also bring up the oil temps when the water temp is higher than the oil. With CHT at 180 and oil at 130 the heat ex-changer is heating the oil and cooling the chts. I will have to try and fly it when OATS are a little warmer and get some better numbers. I was building as fast as I could to try and get it up flying in the heat.......oh well. I may need to look into running a thermostat. Why did you run the thermostat that you did? Do you happen to have a part number for it?

[PapuaPilot]

That's good news on getting your prop balanced; .05 IPS is very good for a piston engine (I can get the PT6 props a lot better).

Did you mark relation of your spinner to spinner bulkhead? If not make sure you do, you need to maintain that position for the prop to stay in balance.

[efwd]

When I watch my video, I wish I were 3" taller or the cabin slightly smaller.