Friday, September 23, 2016

I Have a Short Fuse – on Guillows Lancer

Part of why I enjoy free flight model airplanes is there is so much to experiment with.  In the models I have built with a dethermalizer – DT, I have either used a viscous DT timer or with my electric free flight an electronic timer.  Using a burning fuse although a method that has been used for years is something I have avoided. In the two free flight contests I went to this summer I noticed many people are still using the burning fuse to bring their airplanes down.

Fuse DT on Guillows Lancer

Before building a new airplane using a fuse DT I thought I would start experimenting with an existing airplane I had, my Guillow’s Lancer would be easy to convert as the wing is held on with rubber bands. My thought was to popup the front of the wing to bring the airplane down; as the popup stab is not always adequate to bring lighter airplanes down from a thermal. Many people completely eject the wing off on lighter airplanes with a string attaching the wing to the rest of the airplane. On another airplane I will try this method. 

The Fuse is Burning

To get some idea how fast the fuse would burn and how well the snuffer tube worked, I cut some pieces of fuse and stuck them in an aluminum tube to test the burn rate using a stop watch. To light the fuse I was using a barbecue lighter which isn’t the most reliable method. Several people have given me better ideas on lighting the fuse which I will look at later.

Flying Upwards

The modifications I did to my airplane were to create a wire hook on top of the wing and on the top of the fuselage in the nose area.  From the hook in the middle of the wing a rubber band pulls the wing back while another rubber band running from the middle hook to the front hook holds the wing down in the front until the fuse burns that rubber band. Thin fishing line provides a limit to how far the wing can tip up in front. A short length of aluminum tube glued on top of the nose area is the snuffer tube that holds the fuse.

The Wing has Popped

Maybe Front of Wing Up too High

Last evening turned nice after a huge amount of rain so I decided this was my opportunity to try this out. Where I could fly from was far from where I parked so I stuffed in my pockets; fuse, scissors, small winder, rubber bands, and the grill lighter.  I knew the plane would not fly real long on the winds I could put in so I tried to make the fuse really short, and you thought I was losing my temper. 

Crashing, I Mean Landing on Grass

I made several flights and a couple of times it DT’ed about two feet off the ground. On one flight it did dt maybe 20 feet high and I snapped a couple pictures of it coming down.  The propeller was probably still turning as it came down but I was a little surprised how steep the nose was pointed down as it came down. It didn’t hurt the airplane and it should bring it out of a thermal.  The Lancer doesn’t have a good glide anyway but no doubt if it would wander into strong enough lift it could fly away.

Bill Kuhl

Related Links

Guillow's Lancer Model Airplane

Trying a New Idea on Nose Plug

Fuse I Purchased from Volare 

My Building and Flying Guillows Models Website

1 comment:

  1. I have a old Frank Zaic free flight glider book. It has one chapter on DT ideas, some good others needed more thought. I see some flaws with your idea. Main problem being so near prop. I fear a accelerated burn time or heat increase breaking bands early.