Ray Malmström's Starstream (prop-in-a-box) with Martin’s GG system
Posted: 21 Sep 2018, 12:59
Here’s a few pictures of my almost completed Starstream with Martin’s GG system. The GG system works great - thanks Martin. I will test fly the model with rudder only controlled by a servo at first. Once happy I'll install the GG system again and test using pulse proportional on rudder only, then finally go full Galloping Ghost
There are a few changes to plan. Those of you who know the original design will know the front part of the fuselage hinges down to provide access to the engine for starting and maintenance. Mine being electric powered I decided not to have the hinged front. Fortunately being 6' 3" I have long slim fingers to match so can get to the motor ok - good job too as if I had chubby hands and fingers I will have been in trouble. I've used 1/16" ply on the base of the fuselage instead of balsa with a thin strip of hard wood along the bottom outside edges as skids. Also added a rear skid to protect the birdcage at the rear.
For the wing I have a hard wood dihadral brace and have extended the top spar going the full length so there is a full length spar on the bottom and top now.
I will be recovering the wing as it didn’t go well. The yellow I used first just tore when it shrunk, so it all had to come off with the red. I remembered I had some yellow jap tissue left over from the build of a scaled down Chief. This went on beautifully, but the red is horrible as it doesn’t shrink evenly. So I decided to remove the red and get it on tighter but that didn’t work and replacing the red caused the yellow to loosen. Will leave as is and recover after test flights and when I have some more jap tissue in both red and yellow. You might not notice it so much in the photos but it looks embarrassingly horrible. Learnt a lot though, so some good will come from the experience.
I've since dry strength tested the tissue. The first yellow that tore when shrunk tears very easily, whereas the jap tissue is very strong and difficult to tear. The red tissue I used also tears fairly easily but not as bad as the yellow. In future only the best tissue will be used on open frames. Other cheaper tissue is fine for decoration of sheeted areas.
Below is a short video of the GG system in the model. The cage for the elevator is only taped on and may not be correctly setup yet. But this will be removed so I can just control the rudder with a servo at first, then pulse proportional on rudder only. When I go full GG I'll get the elevator set up properly for which I'll need some advice.
Outlook next week is quiet settled weather, so hope to give it a first flight then.
There are a few changes to plan. Those of you who know the original design will know the front part of the fuselage hinges down to provide access to the engine for starting and maintenance. Mine being electric powered I decided not to have the hinged front. Fortunately being 6' 3" I have long slim fingers to match so can get to the motor ok - good job too as if I had chubby hands and fingers I will have been in trouble. I've used 1/16" ply on the base of the fuselage instead of balsa with a thin strip of hard wood along the bottom outside edges as skids. Also added a rear skid to protect the birdcage at the rear.
For the wing I have a hard wood dihadral brace and have extended the top spar going the full length so there is a full length spar on the bottom and top now.
I will be recovering the wing as it didn’t go well. The yellow I used first just tore when it shrunk, so it all had to come off with the red. I remembered I had some yellow jap tissue left over from the build of a scaled down Chief. This went on beautifully, but the red is horrible as it doesn’t shrink evenly. So I decided to remove the red and get it on tighter but that didn’t work and replacing the red caused the yellow to loosen. Will leave as is and recover after test flights and when I have some more jap tissue in both red and yellow. You might not notice it so much in the photos but it looks embarrassingly horrible. Learnt a lot though, so some good will come from the experience.
I've since dry strength tested the tissue. The first yellow that tore when shrunk tears very easily, whereas the jap tissue is very strong and difficult to tear. The red tissue I used also tears fairly easily but not as bad as the yellow. In future only the best tissue will be used on open frames. Other cheaper tissue is fine for decoration of sheeted areas.
Below is a short video of the GG system in the model. The cage for the elevator is only taped on and may not be correctly setup yet. But this will be removed so I can just control the rudder with a servo at first, then pulse proportional on rudder only. When I go full GG I'll get the elevator set up properly for which I'll need some advice.
Outlook next week is quiet settled weather, so hope to give it a first flight then.