The Demoiselle This page and all text is under copyright, Alien Aircraft 1999©Exciting information!! ("at least for me it was") The Demoiselle has won several awards! Last summer, (2000) I was awarded the Friend Engineering award and (Feb, 2001) I received an award at the Festival Of Giants in Deland Fla. In May, the Demoiselle ended up as a featured aircraft on the Joe Nall Flyin Video! A photo op in June at the AMA Homecoming, Muncie In. Photo in the Oct issue of Model Aviation! And a Trophy presented at The Parrot Head Fly-in in SeptemberAlso ,be sure to check out the photos at the end of the article!
"From time to time, vague descriptions of the manner of constructing aeroplanes have been given to the public. All over the United States there are thousands of persons who are intensely interested in the subject of aerial flight, but until now nothing of a tangible nature has been presented on which work could be started with a reasonable prospect of success. It is a great satisfaction therefore, to be able to present the working drawings of the wonderful monoplane invented by M. Santos-Dumont. As the authors point out, however it would be useless for anyone not possessed of some mechanical skill, and plenty of common sense to attempt to construct a copy of the famous flyer, even with such detailed workings and instructions. --- THE EDITOR."
The above is a quote taken from a 1910 copy of Popular Mechanics magazine. Preceding the article by Arthur E. Joerin and A. Cross, A. M. on the actual construction of the full scale "Demoiselle".
One rainy Saturday afternoon in August 97. I was watching an old movie on TV, Those Magnificent Men in their Flying Machines. Lots of old airplanes, most of which were built specifically for the movie. One in particular caught my eye, the Demoiselle. Much like the Ultralights and Hangliders of today. Yet reminiscent of the days when each flight was a coin toss as to whether you would get off and back on the ground in one piece! I had to build this thing!
Now, where am I going to locate the necessary information? On the internet the question was put to one of the news groups I subscribe to. Several replies with offers of articles and drawings appeared the next day on my e-mail. After a few electronic conversations a copy of an article from Popular Mechanics dated 1910 and some other drawings, appeared in my mailbox.
After reading over the Popular Mechanics article and giving the drawings the once over, it became clear! Not only did it take some mechanical skill and plenty of common sense. It took someone who had very little to live for or was just plain suicidal to build and then actually get into this thing!
Understanding that I possessed at least two of the four mentioned attributes, (I will let you decide which two it is). I decided that the only way to do this thing was to build it as another of my rather off the wall models. Hey I’m the guy that flew the box my first kit came in!!!!
The original Demoiselle airframe was built almost entirely from Bamboo with wire rigging giving the necessary stiffness to the wing and fuselage. As a matter of fact, the wing ribs were simply bent lengths of Bamboo without any lower section! Power was a little on the low end when you consider that it took a twin cylinder engine weighing over 100 pounds to develop about 25 HP. (lots of cast iron in that baby!)
My first intent was to recreate the airframe in its original manner. I live in Ohio, and while Bamboo does grow in some of the backyards around here, none I could find was of the necessary dimensions for the model. So I decided to build it from materials available locally. Also there were some BIG differences between the drawings in the 1910 article and the airframe in the movie. I opted to use the airframe "type" in the movie and I will mention here that this is not a true Scale model I had to make some alterations in order to get MY Demoiselle to fly.
(Please note, during a trip home in the trailer, the original fuselage was damaged beyond repair. A new one was built but different material used than is referred to here. The longerons made from pine and the "former"/uprights made from cedar. This has worked out quite well and reduced the overall weight of the fuse.)
The materials chosen were as follows. For the fuselage, poplar, it has the strength of a mid line hardwood and still is easily shaped for the curve on the front of the fuselage. The wings were constructed as in most models, by using balsa ribs and hardwood spars. An old point ignition Quadra 35cc turning a 18/6-10 prop supplies power. Radio required is 3 channels. Using two giant scale servos for the rudder and horizontal-flying stab with a standard one for throttle. Construction, Begin the fuselage by ripping down a 1 X 6 X 96 poplar board to the required dimensions. Setting the rip fence to cut a grove into the edge of the board, so I had 3/8 inch of material on one side and about ¼ inch on the other. Then resetting the fence and laying the board on its side to allow ripping of 1/2 in. strips. Giving strips that are ½ X 3/8 X 96 and ½ X ¼ X 96. Next a jig is made from ¾ scrap plywood to match the curve portion of the fuselage front. I soaked two foot sections of four of the 1/2 X 1/4 X 96 pieces of poplar in a mixture of hot water and ammonia for a few hours. Using liberal amounts of good furniture type glue to laminate, (I used Elmer's Carpenters Glue) clamp them into the jig and allowed to set for 2 days while they dry. I might also add that when putting them both in the jig, you should insert a layer of wax paper between the two. Then when removed from the jig you will be able separate them. After both parts were removed and the dried glue scraped off with a chisel, run them and the ½ X 3/8 X 96 pieces through a router table using a 1/8 in round over bit on all four corners. With the bottom parts shaped, assembly can begin. Lay both bottom longerons onto the top view of the plan match as best possible to keep centerline and maintain an equal curve on the front. Overall length of the fuselage front curved section is not critical so you may adjust the pieces to get an equal curve. Try to stay within an inch or so in overall length as you will need to add weight up front, and the further out the less lead you will need! Cut the front ends to match up and glue. Use thick Zap "CA" on all hardwood joints. Measure and cut the bottom cross stringers from the 1/2 X 3/8 X 96 strips. Sand the ends to match the curve of the longerons. Please note that a good fit is necessary on all the fuselage joints. Glue in place, these joints will receive more attention later. Refer to the side view and cut the top longerons to length. Make a template from cardboard to match the angle of the front upright section in relationship to the bottom longerons. Cut the 2 front and 2 rear uprights to length using the side view dimensions. Measure on the plan side view the points for the upright positions on the top longerons and mark Install the front and rear upright pairs using the template to obtain the correct angle. Add the other uprights adjusting their length as necessary to fit into position. Do not add the rear wing mount uprights at this time!With a hand drill, chuck up a 1/8th bit and drill through the top longerons into each joint at each upright and insert a length of 1/8th inch dowel. Glue in place with thin Zap, keep going back to make sure each dowel is soaked with CA. This will give part of the necessary reinforcements to the joints! When this step is finished, set the fuselage aside.Next cut out the parts for the wing. Cut 40 ribs from 1/8th inch balsa. You will also need two root rib doublers made from 1/8 lite ply. Next carefully cut out the spar notches in the ribs and rib doublers.The trailing edge is made by laminating two layers of 1/4 X 1-1/2 X 48 balsa. Then, using a table saw, angle the blade so that when ripped one edge is approximately 1/8 inch and the other is the full 1/2 inch. After cutting the two trailing edges, position them on the plan and mark the positions of the notches for the ribs to be inserted. Cut the notches by lowering the blade in your table saw to between 1/8 and 3/16 inch. With the trailing edge against the push miter, slide through on each mark.If you haven't purchased the 3/8 X 1/2 X 40 inch spar material now is the time to cut it! I used some leftover poplar from the fuselage for mine.Take a measure of the leading edge height of the ribs. From 1/4-inch thick balsa sheet, cut the first of the laminations for the leading edge to this dimension. For the second and third pieces, progressively decrease the width dimension by 3/16 of an inch. Cut these also.Position the trailing edge over the plan and if you haven't already done so, cut to length. Pin or weight in place. Insert one rib into each notch on the trailing edge. Using pins or spacer blocks align each rib over the plan to keep them straight. They are quite long and will bow if your are not careful.Slide two of the spars under the ribs and carefully insert them into the notches. Take your time, as again, the ribs will want to move around. It is important that all ribs are as straight as possible! When you are satisfied with the alignment, glue the ribs to the trailing edge with thin CA and the spars with thick CA.Laminate the three pieces of leading edge material allowing the difference in width to be equal on each side of the preceding piece. Position the laminated leading edge against one rib and freehand the curve onto the end of it. Using a small block plane, begin shaping the material. Go back to the wing on the board and check to make sure your part isn't becoming undersize. When you get near the desired shape, position it against the tip rib of the wing you are building and glue. Align the leading edge to the root rib and glue in place. Glue to each rib with CA.Remove the wing from the plan. Sand the entire wing to prep for covering. You will now need to make the outboard or tip rib doublers from 1/8th lite plywood. Lay the wing on the lite ply and trace around it. This is suggested as your ribs and wing form may differ slightly from the one shown on the plan. Cut out and glue to the outboard side of the tip rib with thick Zap. Add the 1/4 X 1/2 inner tip rib doubler as shown on the plan. Install the root rib doublers at this time also! One item of note is the addition of the 1/8th inch balsa inserts between the ribs, these were not included to add strength to the wing, but to keep the ribs from curling over when the covering is done. The finished panel will be very flimsy, don't be too concerned as when covered and strung with the flying wires, the panels will be quite strong!Mounting the wing! Refer to the plans and make the wing mounting parts. These consist of the front engine/ wing mount, front spar mount, rear spar mount and trailing edge mount. All from birch ply, refer to the plans for the material thickness. Build the two spar mount boxes as shown on the plan, making sure that the spars fit loose enough to allow easy installation and removal of the wing but not to allow unnecessary slop. At this point you will need to take into consideration the engine that you have decided to use. Make any necessary modifications to the front engine/wing mount at this time.Return the fuselage to your building table. Level using the bottom two longerons as your zero. With two small "C" clamps, position the front engine mount to the front A frame uprights as shown on the plan. Make sure that the top of the mount is parallel or level to the bottom longerons. Glue in place. Slide the two spar joiners onto the wings and set into place on the fuse top longerons. Make sure the inside of the leading edge is against the front engine /wing mount. With the wing leading edge against the mount, you will notice there is a gap between them, make a filler piece from some of the leftover trailing edge material and glue to the leading edge. Level the wings allowing for the dihedral and block into place. Attach the two ¼ ply trailing edge mounts to the TE with clamps there should be about a 3/8th's of an inch gap between the two trailing edges. Using thick CA glue the two trailing edge mount halves together. Measure cut and install the ½ X 3/8 poplar TE mount uprights from the bottom longerons up to the mounts. Add the wing mount attachments WA1’s and WA2’s to the two spar mounts from underneath the top longerons, glue in place. Finish the engine mount with any modifications you will need for your engine. Drill through the front engine mount into the two front uprights with a 1/8th bit and dowel to the upright as you did to the fuselage joints!Drill through the top longerons to accept the elevator cable guide dowel and the wing rigging dowels, glue in place. Add all the gussets to the fuselage uprights as shown on the plan at this time.With the wing removed from the fuselage, drill through the leading edge root end to allow the insertion of a 5/8 dowel. Cut the dowel flush with the rear and to match the contour of the front of the leading edge. Center drill the dowel to allow the insertion of a 8-32 bolt. Mount the wing back onto the fuselage, level and block up. Using the hole drilled in the leading edge as a pilot, drill through the front wing/engine mount and insert an 8-32 blind nut to the rear side of the mount. Bolt the leading edge in place. Go to the trailing edge mount. Cut the 1/8 birch ply bolt doublers, position on the trailing edge and drill through all three parts. Insert an 8-32 blind nut on the under side of the mount. Bolt the trailing edge into place. This is also the best time to drill the 12 wing rigging blocks and the 4 strut mounts. Insert 8-32 blind nuts into the top of the four strut mounts.Remove the wing from the fuselage and cover. I used Super Coverite. Care will need to be taken to keep the ribs from bowing as the covering shrinks. I had to keep pulling it back loose and re attaching it to straighten the ribs. It CAN be done so take your timeRigging the fuselage! Using a drill bit just slightly larger than the line, At angles, drill through the top and bottom longerons so the bit will exit on the inside just past each cross or vertical stringer. After all are drilled, using Dacron fishing line with a 50-lb. test. Lace the line from front to rear alternating top and bottom, left or right as applies. When all the lines are run, starting at the front of the fuselage, gather the two lines for each side in hand, pull taught from behind the next upright and glue into the drilled holes. Be careful, as the lines in the top longerons are doubles for left and right sides so don’t glue until both sides are taught. You may judge the tightness of each line by plucking them like a guitar string.Reinstall the wing to the fuselage. Make and install the wooden struts and bottom strut mounts. You may need to adjust the length of the struts for differences in your airframe and to keep the trailing edge straight. Using Dacron fishing line with a 50-lb. test. String enough line through each of the 12 wing rigging mounts to allow the distance from the lower strut mount to the top rigging dowel with about 6 inches extra on each end. When all are strung, attach the top lines on both wings to clevices as shown on the plans and connect to the mounts on the fuselage. Thread the bottom lines through the aluminum brackets. Attach the brackets to the strut mounts. Pull the lines taught be careful not to pull the top dowel too far. Knot and glue to the brackets. Using an incidence meter, (you may need to make an extension for the meter to fit the chord of the wing) Measure the angle of the wing at the root, move the meter out the wing to each point of rigging. Adjust the wing to match the root measurement. When satisfied with the alignment, glue the lines to the internal wing mounts with thick Zap.At the rear of the fuselage is a rather unconventional hinging device. The vertical and horizontal surfaces both move in unison with each other, one being the driving force for the other. Don't blame me here folks as the basic unit was designed by Santos Dumont himself! And it does work! Take some time and look over the plans to understand the workings of this system along with the pull pull cabling used to move the control surfaces. You should build the hinging device to fit your airframe, as there may be differences between your work and the plans!Build the stabilizers over the plans using the material specified. Be sure to add the gussets and horizontal control horns where shown. You may wish to cover both the vertical and horizontal parts before you assemble them. Add the rigging, and mount to the hinging device as shown.Balance 1/2 inch in front of the CG mark on the plan, then you may move rearward as you gain confidence in the characteristics of the airframe. I had to add almost a pound of lead to the weight compartment on mine! Being that the Demoiselle is three channels, and has a wing that is flexible along the chord I would suggest that you balance the wing from tip to tip to avoid having to fight a heavy wing on the first flight!You may have noticed from the photos that during the test flights and construction I made use of an 8 oz. Round Sullivan fuel tank. I have now installed a home brew brass tank made from three sheets of K&S .010 #251 sheet.The first step is to make the round center section and crimp the joint closed, then solder. Next, make a cone from a sheet of paper and set it over the end of the round/tube section. While holding the cone still with one hand, using your finger push against the paper at the edge of the tube section. This will give a crease in the paper. Remove from the tube, cut the tape joint where the outside lap meets the inside and unroll the cone. Cut along the crease to get the curve for the cone bottom edge. Lay the unrolled paper on one of the sheets of brass and scribe the outline. Freehand an extra 1/8 inch or so around the curve and the same to make a tab to join the edges. Work the brass using a dowel rod to form a cone. Snip into the edge of the curve to the scribe line and using pliers bend back slightly toward the inside of the cone. These tabs will be your solder joint reinforcement. Insert the cone into the brass tube section and solder. Lightly push the overlap joint on the cone together and solder closed. Snip off the point of the cone and insert a length of 1/8 in brass tube bent down to come near the bottom of the round/tube section inside for a fuel pickup. Repeat the above steps except for the 1/8 brass tube to complete the other end of the tank. For a filler tube, I used an externally threaded brass valve stem from a big truck. Remove the valve, drill out the threads and solder into the top of the tank. Now go to the automotive store and buy a chrome metal valve stem cap for you gas cap! Mount the tank on a cradle made from brazing rod.Flying the Demoiselle?? Yes it does fly! My first attempts were with no success,I made 20 trips up and down the runway and never got off the ground! The problem being simply not enough power! I had used a weed trimmer motor of around 25cc’s and it just didn’t have enough to break loose from the ground. I modified the mount and installed my old Q35 and gained success! It ran about 20 foot down the runway and was off! The only trim neededwas a small amount of down elevator. Handling is similar to a three channel trainer with lots of dihedral.It will really swing into a turn. One caution! The Demoiselle likes to weathervane so try to fly on calm days. Landings in a crosswind are something else! Flight speed seemed to be the same whether at full or half throttle I wonder why? After all, it's such a clean streamlined airframe!If you are looking for something different,(is different the right word?). Then the Demoiselle is just the ticket! It is always a hit at flyins or even on meeting nights at the field.If you build the Demoiselle, and have questions, feel free to contact me by email at: rlcharles@cinci.rr.com . I really would like to hear from any of you!Randy CharlesAMA 113688Alien AircraftPrinter Friendly Version
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Mike Cisler just droped these photos to me of his Demoiselle! He has really done some beautiful work here. He constructed his Demoiselle to have the tail section removeable. He also has come up with some really cool ideas on connecting the rigging "wires"! Just click on a photo to see the full size!
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