Re: Just couldn’t sleep.

batjac Sun Jun 29, 2014 11:55 pm

ian1954 wrote:Hi Mark,

That is not a "Butcher Bird" (FW190) but a Messerschmitt (ME109). Well BF109 actually

Ian, the Super Stunter from the 70's was indeed the -109, but the plans that came with the foam wings were for the FW-190:
foam wing - Just couldn’t sleep. - Page 2 DSCN1869_zps3be2abba

foam wing - Just couldn’t sleep. - Page 2 DSCN1869_zps3be2abba

The reason I was hoping to compare them, even though they are models of two different planes, is that they use the same wings, and the control moments are within about a half inch of each other between the Super Stunter, and the plans plane. I don't think it's going to be much of a comparison, though. I weighed the Super Stunter without the parts I am missing, and the weight is 8.65 ounces. Once I get the tank in for Brünhilde, I'll weigh her and see how much lighter she is. I think the weight of the plane without the engine was something like 4.5 ounces. I don't recall exactly.

I see from your Stunter picture that the plane used a three bladed prop. Does anyone know what kind of thrust the three bladed prop gives, versus a two bladed 6x3 or 6x3.5 prop? And, where did you find that picture? I've done a couple of searches looking for Stunter pictures, but didn't find all that many.

The Memory Challenged Mark

batjac Sun Jun 29, 2014 11:58 pm

Cribbs74 wrote:Turned out great Mark.

Do you have any engine offset dialed in? Couldn't tell from the picture. I bet it flies well.

Ron, the plans call for 0° offset, so I was going to initially try the plane at 0-0-0 offset and see how it flies. If it's unmanageable, I'll put a couple of washers under the front of the lugs.

The Straight Line Mark

batjac Wed Jul 02, 2014 9:28 pm

Oops! Wrong thread...

The Confused Mark

batjac Thu Jul 10, 2014 8:55 pm

I test flew this at the Independence Day fly-in at Delta Park this past weekend. I'm going to have to put some out thrust on the engine. It just wasn't keeping any tension on the lines. You can see me in the video constantly moving to the right. The wind was from the left of the camera, and I was constantly having to step back to keep line tension when crosswind. You can see at the end of the video where the lines just went too slack to keep control of the plane. The hang test was good, so I'm good with the leadout position, but it's just not enough when the wind blows or I get it overhead. It also floated a little more than I wanted. If, after putting some nose out, it doesn't satisfy me, I'm going to put on a TD and see how that works.

The Slack Mark

**RknRusty** Thu Jul 10, 2014 9:03 pm

Hey Mark, I think all it needs is a little more go. What prop was that, can you go smaller, like a 5x3? A Medallion would be great if you have one and would be somewhat less finicky with the fuel draw.
Thanks for the video.
Rusty

batjac Wed Aug 27, 2014 1:03 am

Okay, now that I have a better idea of where the c.g. should be on the wing, I've tweaked this plane a little bit. I moved the engine back a half inch to bring the c.g. back. And, seeing how much elevator Cox put on their ME-109 Super Stunters, I increased the elevator area on this thing by about 25%. Still a lot less elevator than the Cox production model, but it looks more correct using the TLAR standard. When I built this plane per the plans, the elevator seemed pretty small for the wing area. I also put in a different profile wedge tank to get it back closer to the wing, and put a couple of washers under the front lugs to give it some right thrust. This weekend should get a few good flights in to test things.

Rusty, I have a 6x3 on the Medallion right now. I thought about a smaller diameter prop before, but wasn't sure how well it'd do on a plane with such a large wing. I'll have to try a 5x3 and a 5x4 at the field to see how they compare with the 6x3 on this plane.

The Correct Mark

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