This project started with the idea of keeping it simple. I initially thought I could use a fixed pitch propeller and compromise the top end performance. I purchased a full composite Global Aircraft QCS-10 ground adjustable propeller. This propeller turned out to be a work of art. However, after lots of calculations and some practical experience from a Glastar builder with a similar ground adjustable propeller on a Subaru, I decided that it just wasn't safe to use anything but an in-flight adjustable propeller for this engine.

Next I purchased a Quinti three blade, electric, in-flight adjustable propeller. I designed a control unit for this propeller to allow operation from a set of remote, stick-mounted switches. It isn't constant speed, but does have the capability with an upgrade from the manufacturer. At this point, I am happy with the non-constant speed setup.

To install the Quinti on the Marcotte gear drive, I had to fabricate a way to mount the brushes that transfer the electricity to the slip rings.  I used the machined surface of the drive unit casting as my attachment point. After carefully lining up the brush assembly, I used a 12" long drill bit, through the brush holder mounting holes, to drill the pilot holes into the casting.  Then I tapped the holes with a 1/4"-28 tap.  I used some 1/4" id x 7/16" od aluminum tubing, cut to the proper length, as the stand-offs.  Last, I ran long bolts through the holder, through the aluminum tube and into the casting.

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The Marcotte prop flange had to be slightly modified as well.  The Quinti came with 5/8" drive lugs and 3/8" studs installed in the back of the prop hub.  The gear drive only had 3/8" holes for the studs.  I had Davis Tool Inc machine the gear drive hub for the drive lugs.  Doing this required that special washers be fabricated to keep the nuts from pulling through the hub. I had them make me these washers from stainless steel while they were machining the hub.

MT Propeller:

Flight-testing proved to be detrimental to the health of the Quinti. Well, at least with me flying... So, here's the story for those of you that haven't heard it.

After the "incident" I was fortunate to find a used MT propeller from a plane owner that decided he had enough fun tinkering with his Subaru and opted to change to a conventional aircraft engine. The MT has always been my preferred propeller for the Subaru, however, the price to purchase new is prohibitive for my budget. I was able to purchase the MT for less than it would have cost to have the Quinti overhauled.

This MT is an MTV-7, electric, constant-speed version complete with the electronic controller. To fit it to N466DM I'm having a new prop flange made for the Marcotte drive to fit the SAE-2 propeller. The prop parts were shipped from Oshkosh aboard a truck by Tony Partain. They arrived on August 9th, 2008.


The next change needed was the spinner. The MT came with a 13" and the Glasair requires a 12". I ordered the spinner from MT Germany in August and had the new spinner in 4 weeks. When the spinner arrived I attempted to install it and found that the blade cut-outs were incorrect. The 12" spinner back-plate is on the right in the first photo. The original 13" spinner back plate shows a much more angled cut-out. The second photo shows how much more needs to be cut out as indicated by the back-plate sitting about 1/4" above the prop hub.

While deciding the easiest way to correct the spinner issue I installed the electric, constant-speed, controller. Due to my limited dash space it was a challenge. Since I didn't like where the fuel gauge was located I decided to install the controller in this location. I moved the fuel gauge to the top of the dash next to the lift reserve indicator.