Update time. I have been on other projects recently but I'm back to the plane now.

Had a good hangar talk with one of my Stinson buddies and we figured out another way to make a second access/cargo door to load the passenger area. The idea is a suicide door with a detaching rear pilot door jamb and tube. I like this idea better than my original idea of making the passenger cab cross tube removable. It's easier and leaves more of the original structure intact.

Imagine the pilot side rear door jamb and tube detaches top and bottom and swings out as part of the rear cargo door. The associated fuselage tube would secure with an over center pushrod and interlocking mechanism top and bottom that would be rigid enough to preserve the structural integrity of the fuselage. That tube/jamb is a 1" x .035 wall so the load on it can't be huge. The front door frame tube is twice as thick walled at 1" x .065. I'm considering a truss detail above the door opening to give the open frame some more rigidity.

I made a super rough Mockup of the door below.



Imagine that centre post gone. It's a huge opening compared to the stock doors and wold go a long way to overcoming what in my opinion is the 108's biggest drawback. Cargo loading. Let me know what you think.



Top and bottom would lock with a modified version of these:

Wayne Alsworth had a 108 that he did a big rear door on. I have some pictures somewhere. I'll see if I can locate them. He did a truss all the way around if I remember right. A friend of mine has one that is experimental and has a huge door back there, to load a Honda 3 wheeler.Somewhere I should have some pictures of that too....
John

The levels of "creativity" your taking this project too are fantastic, amazing work sir.

Thanks, Maplefit.

hardtailjohn wrote:Wayne Alsworth had a 108 that he did a big rear door on.
John

I'd love to see that.

Made a dessicant insert for the case using some fine stainless mesh I had kicking around. I already have dessicant plugs in the cylinder heads but the cam and lifters are not exposed to them. The hydraulic pump cover is a good place for this because there is a lot of room in there without the pump. I cut a temporary gasket out of cork material to seal in the strapping that I wanted to expose to make sure I remove it before flight! I will probably make up a permanent external dessicant system using this location. I love on the wet coast so I figure this will extend the life of my engine.

FYI, the blue indicating silica gel type turns pink when it needs to be dried out again. Blue means it's dry, pink means it's waterlogged. I notice a lot of people think it's the other way around and are risking corrosion in their stored engines. They can be dried out in couple of minutes in a microwave once you have removed the beads from the plastic plugs. The beads I used for this are not the indicating type. I just dry them out at the same time I do the plugs.

Getting close to finishing the fabrication of the mount. I decided to add a double cross brace and hard point on the fuselage where the cockpit cross braces meet at the middle. Since I'm planning on putting this on floats, I want this mount to be super skookum. The tubes where the mount bolts to the fuselage on the left and right upper sides are just 5/8" x .035. That seems a bit light for an engine that will be about 100 lbs heavier then the Franklin. Instead of messing with increasing the size of the tubes. Normally, there is one cross brace from the firewall boss to the opposite side lord mount but that would not spread the load distribution and does not increase the cross section of tubing on both sides. My solution here, accomplishes both of those goals as well as the cross bracing.

I decided to just add a mount point to the existing frame members, right in the centre. In front of the Peltors, there is a good strong cluster I will drill through and install / weld in a piece of 5/8" DOM tube. I have seen this on some other (non Stinson) mounts. I added the guide for it to the jig as you can see in the pics below.

The 260hp maules use a 5th point like that. Seems like an obvious improvement. Thanks for the project updates!

Man you have some seriously developed; well evolved welding skills, very nice work.

Keep checking for updates on your project Marcus, probably have a lot of progress to share?

Keep up the great work/
Marcus

Keep checking for updates on your project Marcus, probably have a lot of progress to share?

Keep up the great work/
Marcus

I know this is an old thread, somehow I am just now seeing it. Such awesome work! In the middle of a Stinson wing project myself, so this project is very interesting. How is the project coming?

Mini update. Been a little busy with life but had some time to wedge in some work on the project.

Alternator mod. Turning a Denso internally regulated alternator into an externally regulated unit requires the disconnection of one of the bus bars. I think most of the units from B&C are modified Denso units. These are very reliable can be had quite reasonably on ebay and modified for experimental use. I have a nice new Electrodelta VR2000 regulator to take up the task of regulation which will be mounted where it can be cool, dry and vibration free.

Phenolic pad is for mounting the new connectors.



Checking the swing out of the engine mount: It works great, if a little tight. Just a few thou of sag when open. It easily pops back into the tabs. I'm actually surprised how little it sags because that engine weighs a little under 400 lbs.



There's more when I get a chance.

Nice progress!! That swing-out mount is cool.

Hi, so fun to see updates! I have some
Minor progress on mu 108-projects. I now also have a IO-540, an engone mount (unfortunately not a swing out), a pa-25 metal prop. Also managed to get an EAA builders permit for the 4-door fuselage with that engine and 3000lb gross. There are however loads of work to be done before that flys…

Meanwhile my other 108-1 project is getting a IO-360 200hp engine and a constant speed prop, doors like your moc-up etc… going on 2425’s….

Keep updating, very cool build!

Regarding alternators, I am
Using a lightweight alternator with built in regulator, works like a charm and costs 100usd…