Geek's STi Build

[Geek]

Still working on getting some of the small stuff done with with programming the Garmin G3X and G5 along with the auto pilot. Got the auto pilot arm limiter installed on the roll servo but still need to do the pitch. Built backing plates for the hold down attachments for the baggage area, installed carpet on the floors and installed the floors back into the fuselage. Fabricated and fit the left wing closeout cuff, installed the attaching nut plates and got it ready for paint. Not as cool as the ones people are making with the carbon fiber but they will do the job. Installed heat reflective material on the base of the lower cowling that is just below the muffler/exhaust of the engine. Hoping to keep the cowling itself a bit protected from the heat.

Baggage Hold Down 2.JPGBaggage Floor.JPGWing cuff 1.JPGWing cuff 3.JPGCowling Heat film.JPG

[P Johnson]

Have wrestled with how to mount the sensors for the DynaVibe. Thinking thru things like the effects that the alternator pulley and alternator might have on balancing or taking the alternator off and doing the balance. Got to say I got some good input from Delta Whiskey that helped me make sense of stuff. So armed with that, I came up with this solution. The instructions say to mount the transducer as far forward and center as possible on the engine and this fits the bill. Built the side brackets out of doubled .06 aluminum and then riveted them together so they hold the quarter inch plate on the top nice and sturdy. This should work out I think. Appreciate all the help I got with this so I can move ahead now that I've started the engine and all.

Gary

Attachment 32719Attachment 32715Attachment 32716Attachment 32717Attachment 32718

Gary,

I have balanced many Lycomings but only two Rotax 912 engines, last weekend I balanced the second 912uls, for some reason I placed the reflective tape on the spinner backplate instead of one of the propellor blades and I could not balance the propellor, the DynoVibe readings were consistent when repeated but adding weight just changed the angle but not the IPS which made no sense, I removed the reflective tape from the spinner backplate and placed it on one of the prop blades, repositioned the optical sensor and had the prop balanced to 0.06 IPS in two runs. It may be of interest but the unbalance prop reading was 0.72 IPS, after placing 20g of weight the reading was 0.12 IPS it took another 5g to read 0.06 IPS.

[Geek]

Gary,

I have balanced many Lycomings but only two Rotax 912 engines, last weekend I balanced the second 912uls, for some reason I placed the reflective tape on the spinner backplate instead of one of the propellor blades and I could not balance the propellor, the DynoVibe readings were consistent when repeated but adding weight just changed the angle but not the IPS which made no sense, I removed the reflective tape from the spinner backplate and placed it on one of the prop blades, repositioned the optical sensor and had the prop balanced to 0.06 IPS in two runs. It may be of interest but the unbalance prop reading was 0.72 IPS, after placing 20g of weight the reading was 0.12 IPS it took another 5g to read 0.06 IPS.

Paul - Thanks for bringing this back up and reminding me I should provide the rest of my story so to speak. Hopefully your experience and mine will help others. I didn't have your experience of doing the balance before mine and I struggled for literally a day (16 runs - I'm a slow learner) of getting readings that moved around and not getting the job done. I was thinking that maybe my DynaVibe was wonky but I knew it had been successfully used previously. Stepping back with my elixir of improved thought (bourbon) in hand, I knew there was something I wasn't seeing and tomorrow was another day. My hint that the backing plate was the wrong place for the tape was taking the spinner off. Things settled down a lot then and the clue light came on that maybe there was a reason the instructions say to put the tape on the blade. Put my tape on the blade as well and all was right with the world. Thanks again.

Cheers
Gary

[Geek]

I am in the midst of doing little things that need to get done which seem like I am not doing much at all. But rather than program the Garmin, I got to work on hardware a bit today. One of the things on my list was coming up with a way to retain the hinge pins on the door hinges so they don't just slide out. Have read on the forum of many different ways to do this but thought that the set screw method seemed the way I liked most. Drilled and tapped the hinges to accept a 6-32 set screw, filed a very slight flat spot on the hinge pin itself where the set screw hit it and locked all the hinges in. Needed a bottoming tap to make this work and your basic tap and die set or local hardware had none. Hardware store didn't even know what it was; "They all come with that tapered end so you can get the threads started". I went to an old set that was passed down to me from my Dad and there it was - the 6-32 bottoming tap. I just smiled and thought that here I was, a 70 year old man, still being helped out by his Pop. A good thing. Also primed the wing close out cuffs and VGs so they are ready for paint.

Hinge Pin Retainer 1.JPGHinge Pin Retainer 2.JPGHinge Pin Retainer 3.JPGVGs 1.JPG

[bbs428]

Nice work Geek!

I also have some old tools from my "pop" that serve me well. Had a smile reading about your 6-32 bottom tap.

I replaced my door hinge pin with a cotter pin bent ever so slightly as to not come out at an inopportune moment.

Not sure if I'm going to do the "VG's". I know their good for a few mph off the stall speed. Where did you get yours from Geek?

[alexM]

Too late for this occasion but there's a Tacoma Screw in Wenatchee.
They wouldn't blink if you asked for a bottoming tap, plug tap, etc.

Much cheaper (if you know ahead of time) would be to order from McMaster Carr

[Geek]

Too late for this occasion but there's a Tacoma Screw in Wenatchee.
They wouldn't blink if you asked for a bottoming tap, plug tap, etc.

Much cheaper (if you know ahead of time) would be to order from McMaster Carr

Thanks Alex. Good to know. There has been more than one occasion that I needed something other than a starting tap and been frustrated. Tried a couple places (like Fastenal) and they didn't have them there. Could get them but didn't have them. Appreciate the steer there.

Gary

[Geek]

Mounted my doors and did the final fitting for the latches. They work perfectly and while close, don't hit the wing. Mounted my nameplate below the horizontal stab access panel using a backing plate fixed to the backside of the Oratex with adhesive to sandwich the skin between the two plates. Since I have finished the prop balance, I removed the DynaVibe parts and did a final install (read safety wired the bolts) on my external alternator. Did an engine turn after the install and the alternator puts out a nice 14.1 VDC from around 3500 RPM to WOT.

Left Door 1.JPGLeft Door 2.JPGName Plate.JPGAlternator Final.JPG

[jiott]

Worries me a little that you said your doors are "close" to the wing. I did that too, and when I have the door open and engine running, the vibration causes the door to slightly contact the wing and now I have scratches in the door plexi. I should have left about 3/4-1" clearance when static.

[jiott]

Its not really engine vibration that causes the problem, its the propwash.