Dual STI build log

[Backpacker]

I wish there was more to report but there has been a bunch of head scratching. Working on the cowl I ran into the problem of my naca vent hitting the turbo and not having enough clearance. Crazy thing is 1 of the 2 builds has an issue. My brothers plane is tight but has clearance. Not sure what the different between the two is. Little differences add up when it comes to the cowl. Mine, there was no way that the Naca was going to clear so I had to modify the vent. I am worried about getting enough airflow, but I guess time will tell. I think we are defiantly going to leave the cowls unpainted for possible mods that may need to take place. Mic, one of the dual STI's in Canada sent us one of his 915 intercooler to see if it will fit. I need to get some more ducting and I think I will be able to get the 915 intercooler on the side to work. I am going off Kitfox recommendations to only run on the top of the engine as our last resort. The side should work. Just need to figure out naca vents to feed it fresh air and heat shield it from the turbo/header heat. Once I get the inter-cooler plumbed I think we are back moving forward. I will be able to get the throttle cable routing figured out, which I can then get the panel drilled and get powered coated and ready to start wiring. We can then start pluming the motor and working on the firewall wiring also. While we have been waiting for the intercooler to clear customs I have been working on getting the butt rib close-outs installed. Hinges built and doors installed. Also got the bubble windows and latches installed. I had no mishaps with the acrylic which I was nervous about. I now have taken the doors off and put away for safe keeping until final install. As I wait for parts to arrive for the ducting on the intercooler I think I am going to start working on getting the windshield started, but nervous about messing it up. Fingers crossed! Here is come pictures for now!

Setting the clearance of the radiator off the cowl.

Getting ready to modify the NACA to clear the turbo when installing the cowl.

Hopefully the vent does not restrict to much airflow to cause overheating issues???

Vent is done and visually looking from the front you can't tell.


It now has adequate clearance. Hard to tell in the picture but there is about 1.5" of clearance now. Still need to heat shield it but I think it should be good??


Naca opening cut.



Cowling is getting closer!



Butt rib closeouts done, hinges installed!


Windows installed and weather-striping installed and latches installed!

Sometimes you just need to roll it outside!


Intercooler is going to work I think!!


Found a K&N filter that fits and now just need to run a little tighter bend to get the discharge side of the cooler to intake. Not optimal running tight bends but running low boost should be fine.

Whats the model / part # of that K & N filter? Is that a Rotax intercooler or Edge Intercooler? Thanks again for the last pics, appreciate it.

[Shadowrider]

Post #543 page 55 has all parts info.

K&N Filter RU-830 (Summit Racing)

Intercooler. (edge will build you one) We bought a 915 takeoff. Rotax part number 888962

[Backpacker]

Post #543 page 55 has all parts info.

K&N Filter RU-830 (Summit Racing)

Intercooler. (edge will build you one) We bought a 915 takeoff. Rotax part number 888962

Thanks, i checked out your Post #543 and this filter part # is not valid with Summit or K&N(i called both of them)...K&N said it should be 4 numbers. If you find the filter part # that would be excellent...there is so many models, i saw some very similar part #'s for the filter.

thx

[Jcard]

This is what I used.

[Backpacker]

This is what I used.

Excellent, thx!

[Shadowrider]

Sorry its missing a zero. RU-0830

Wish I could go back and edit the parts listing?

[Shadowrider]

Went flying to IBEX lakebed early in the morning. Wind was dead calm. I was flying low across the lakebed in perfectly smooth air and my TAS showed 102MPH. Ground speed showed 112mph. G3X showed 8mph tailwind? I know groundspeed was correct, but I am wondering if my Pitot system has a small leak? I got reading and I guess 1/4 air line press-in connectors often leak. Thinking maybe the press-in connector I used is leaking slightly. Vans forum many say don't use the press convectors because they leak? Avionics guy is coming next week for the Global and I will have to do a pitot static test.

[Delta Whisky]

Dustin - why not test for a leak? I don't know what type of pitot tube you have but if it is a simple tube an airtight connection to a syringe will work. Just SLOWLY and carefully apply the slightest pressure to the system, watch your ASI climb to about 100mph, hold that setting and see if the air speed drops off.

Your story reminds me of insurance company required instruction for the first 10 hours in my first RV-6. Having taught only in C-150s, said instructor was mightily impressed with cruising at 150mph. (Yep, the irony of the insurance company accepting that instructor is apparent.) Thinking "why aren't we making the 180mph most folks get?", I found TWO leaks in the system. That's why I don't have "connectors" in any plane I've build since then. All connections are tube-to-tube with a short piece of silicon tubing. One example can be seen in this picture:
Pitot tube installation.jpg

If your system passes the pitot system leak test, then building a manometer or borrowing a known, good (calibrated?) ASI is in your future. Just connect the "calibrated" unit in parallel with your ASI and compare readings as you increase pressure. There are one or two more issues if one is testing a mechanical ASI but it appears you talking about your Garmin only.

I'm not sure what you mean by the Global and pitot static test but unless you fly IFR this shouldn't be a concern.

[PapuaPilot]

You could also do a leak check on the static system. You need to put a little suction on the static system to raise the altitude at least 1000' higher and it should not lose more than 100' in one minute. Be very careful doing this, as it is easy to apply to much suction and damage instruments or your AHRS.

I have seen similar errors in my G3X system and have decided to live with it. Sometimes the wind calculations & GS vs. TAS seem a little off. Besides the pitot/static system I wonder about the magnetometer possibly having slight interference or a slight azimuth error in installation.

[Shadowrider]

I have thought of re-calibration of my magnetometer, but that seems like it would only give me errors in regards to wind direction. I have noticed that I have had a 10mph tail wind both directions? Seems like pitot system is leaking a bit to read low indicated airspeed. I am going to try and leak test the pitot system and change out the push-lock fittings and see if I notice anything different.