Drop Me A Line (oz12739)
About this Plan
Drop Me A Line. Free flight towline glider model. Ritz wing construction.
Quote: "DEAR JOE: Knowing that you're the type of model builder who enjoys building and flying towline gliders, and knowing that you appreciate anything new in the way of technique, structure, and design in model aviation, I am sure you will be very much pleased with this set of towline glider plans.
This glider is the product of many years of practical experimentation. It combines lightness, extreme strength, and exceptional performance. It is a challenge to the builders of the large, high aspect ratio type of towline glider, and I am sure that with this ship you will have no trouble in competition against the very best in the model gliding and soaring field.
You will find the plans very complete. However, here is some information to help explain the interesting structure of this model.
The fuselage is constructed by first cutting the main horizontal keel of 1/16 medium bard sheet balsa. Then cut the upper and lower keels of the same material. Cement the upper and lower keels to the center on each side of the main horizontal keel: When this is dry add the cross braces which are of 1/8 square medium hard balsa, to the positions shown. I don't think you could ask for a fuselage more easy to build than this.
The tail surfaces are constructed by cutting them to outline shape from %a" medium hard sheet balsa. Sand them as usual. and cover with colored rubber model type tissue, using dope as an adhesive. Cement the rudder to the stabilizer.
You have probably noticed that the wing is quite unusual. Well, Joe, this wing is really nothing new, but isn't too well known to the average model builder. Among the experts, it is called a 'Ritz' wing. Its outstanding features are extremely high lift per square inch of area and high strength-to-weight ratio. Its structure is quite simple as you will see.
Begin by cutting the outline shape from 1/8 medium hard sheet balsa. Glue these sheet sections together as shown by the plans. Next cut the three templates (one for the center, one for each tip) of sheet balsa. Moisten the entire wing with lukewarm water and pin it to the templates as described on the plans. Allow this to dry for at least three hours - preferably overnight. This will 'pre-form' the wing to its required airfoil shape.
When dry, remove the pins from the wing and insert the ribs in their respective positions. These ribs are cut from 1/8 medium hard sheet balsa, using the template as a guide, as shown on the plans. Join the two wing halves just as you would those of a hand-launched glider. Three inches of dihedral is required at each tip. There is no need telling you that, this joint should be strong, so don't spare the 'stick-um'..."
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User commentsHello, Can someone please help me with the CG position for this glider? I intend to make it a 2 channel RC, slightly enlarged... Many thanks, Eduard.
Eduard - 28/06/2021
Hi Edward, I would put the CofG between the tow hooks and err a little bit forward of that position. I'd then do dive tests to see if that suits. (Push the nose down and then center the elevator and see if it recovers naturally)
John - 30/06/2021
If I understand correctly your indications are for setting the CG after the model is built? My biggest issue is with the distribution/placing of the rc stuff during the build stage vs the balance of the model free of the rc gear... As you suggested, I will consider the CG somewhere in between the hooks plus a bit fwd and work from there. Many thanks!
Eduard - 30/06/2021
Make a full-sized card cutout of your battery, RX, and servos and place them on the plan roughly where you think they should go. The rule of thumb is the heaviest item to the front, which would be the battery. I would leave the battery bay with plenty of space so you can move the battery to adjust the CofG. Use sticky back velcro to help keep small position adjustments secure. I'd place the servos to the rear to keep the control runs short and 'slop' free. The name of the game is experiment, it's fun.
John - 01/07/2021
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