#51
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Technique to Simply Construction
Working on the new design, had a thought about simplifying construction.
Till now have been separating things into their own parts, this takes time to glue say 4-sides instead 0f 2. Well if the sides of the fuselage has an added top skin and fold line, this will get rid of several glue joints, will save lots of gluing and time waiting for it to dry. Also should have a straighter build due to less glue joints. Will also reduce the amount of glue tabs, weight savings. Just printed the new design with the major components designed to fold and glue together for a test of this method. If it works, it will reduce weight by using less glue and getting rid of glue tabs. Mike |
#52
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Rubber Band Plane
Designed a whole new model.
It is a one-off design called the Rubber Band Plane. The box structure for the wings slides back and forth. Presently ready to glue into place, the wings/tailfeathers are in the proper location from each other. The box structure was designed so that the parts that I would normally make, are now included on the main part with a fold line. This saves gluing steps and works like a charm. You can see both of the wing box pieces ready for gluing after scoring and folding the sides: Still have to do landing gear and install the rubber bands. Wing can slide back and forth, once determine where it needs to be, will tack glue it into position. The wings on this model are different. The 110lb index is part of the load bearing structure. The skins have three ribs glued in specific spots. The one closet to the wing root also has a double skin laminate it is glued to. The double layer skin with the rib glued at the end creates a box to carry flight loads, there is another rib mid wing and one at the tip. This creates a series of boxes to carry the flight loads without using a spar. Will this work? Don't know but fairly strong, can pick the model up at the wing tip. Here is a photo trying to show the wing ribs, only the mid wing and end are visible. The fuselage is the rolled paper tube. Using 110# Index to make the model 3 each 11x17 sheets are needed. 1-sheet of 20# 11x17 bond copy paper was rolled into a tube to encase the rubber band. Plan to go with 2-each 3/16" rubber bands at first. 6" prop, but can go to 8" special once get the landing gear is done. Mike |
#53
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Flight Test Results
Today at lunch time, wound them up and turned 'em loose.
The P51 rolled about 8ft and took to the air, crashing into our company truck, slight damage to the wing and landing gear leg was removed. It accelerates fast, climb angle was shallow after 14 feet from start point it hit truck about knee level. Vans RV-6 does not have enough acceleration in a 15ft takeoff to leave the ground. Hand launched real shallow descending right turn as evidenced in this short video. https://youtu.be/zS9603hdnO4 Model still had plenty or revolutions left for extended flight. Only thing left to do is add the 1/4" rubber bands the P51 uses. Batteries on video quit, only 1 video to show. The simple design that is on the hobby table is not quite ready yet, it should be ready tomorrow for flight testing, the RV-6 will have a hot rodding session right after the Rubber Band Plane is completed. Bent the wing and rudder to get rid of the right turn tendencies. After 4-flights + 2 hi-speed taxi tests that came to abrupt halts, the RV-6 is ready for more, no damage... Mike
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Cardstock Property Tables and Terms Flying Cardstock Models http://www.papermodelers.com/forum/m...uers-projects/ Last edited by mbauer; 02-24-2020 at 10:21 PM. Reason: taxi |
#54
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Mike, That's a great looking model. I bet it will fly as good as it looks. What's the wingspan?
Curt |
#55
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Hi Curt,
The Rv-6 is 30", the P51D is 22", and the new design is 26". Thank you. Mike |
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#56
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Three Birds For Flight Test
No surgery needed to add a third rubber band to the Vans RV-6. Added 1 band of the 1/4" Super Tan to see if it makes a difference for top speed.
The P51D needed its gear glued back into place. Done. The wing root was torn, this needed more glue, does have some permanent damage to the wing in this area. The new model is done. Weight & Balance complete. It weighs in at 3.7oz: needed to add 1oz of weight to get it to balance. New model specs: 26" Wingspan 17" Long 6" Prop spun by 2-strands of 3/16" Super Tan Rubber Weight: 3.7oz Index 110 for cardstock used Mike |
#57
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Three Flight Tested Today: Videos!
Ok, for some reason the batteries were charged in the camcorder today.
Got several flights, out of the three, have two videos, the third plane was a big disappointment. Failed to take off under its own power, so tossed it with a huge shove, immediately stalled and nosed in, wing ripped almost in half. Not Good! First video is the P51D model taking off and then landing before another take-off: abrupt stop at the end. Soon as model climbed out of "ground effect" it stalls, lands continues the take off roll gets airborne before stopping into a cabinet. https://youtu.be/Jp4klT7gfhI Now for some videos of the star flyer for the day: The big Vans RV-6 model. Added a third rubber band last night, instead of installing two new 1/4" rubber bands. Added the 1/4" wide with two of the already in place 3/16" wide ones. Thinking that the two 1/4" ones together don't have nearly the endurance of the 3/16" ones. Why not see if adding just one 1/4" as the third strand, if that might work. The following videos should answer that question. The RV-6 can take off on its own, climbs like a real RV (until it stalls or hits a wall). After each flight it still had plenty of revolutions available. Take Off from the ground video: https://youtu.be/a14O02LnXao Finally a hand toss takeoff put it into the rafters of a very tall warehouse, whoops. The landing from this caused a wingtip to "pop" apart. https://youtu.be/ljprO1ipKoY These videos are way better than the one posted yesterday! Show actual flight capabilities. Total Flights Today: New rubber band plane: 2 with severe damage after second flight, important lesson learned on this one! How to make an airplane that doesn't fly... P51D Mustang: 4-flights all take-offs from the ground 4th flight broke the other landing gear leg. Learning that this style of landing gear isn't working so well. Balsa wood inserted and glued to wing doesn't work as well as one piece wire! Changes are in the future on the second build. Alpha build has proven its points. Vans RV-6: 8-Tough Model! 6-flights from the ground, 2-were hand toss. After 7th flight popped the left wingtip apart, flew #8 with a really awesome looking left turn
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Cardstock Property Tables and Terms Flying Cardstock Models http://www.papermodelers.com/forum/m...uers-projects/ Last edited by mbauer; 02-25-2020 at 10:33 PM. Reason: Spell Check/added flights made |
#58
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Combined Parts Printed
Working on another RV-6 model. Decided to try the combined parts idea. Had already printed the fuselage on a sheet of cardstock.
After combing the parts into a single part, printed it and this is what it looks like compared to the old way: Less glue in an area where weight is critical, also by combing to both fuselage sides, it is more square for construction. Already glued it, worked great and saved time when gluing= less glue joints. Guess other designers have been doing this for a long time, just thought of it the other day...A little late to the water trough! Working on some updated changes to the models. The RV-6 is first to get the build, the P51 will get done soon as well. No more indoor videos for these. RV-6 when inspected had lots of damage from its several crashes, abrupt stops. 1) Fuselage side where wing root leading edge ripped and torn both sides from wing hitting stuff. 2) Wing root tabs torn from wing where they are inserted into the fuselage 3) 9.5" propeller has several large chunks missing on one blade and only one chip on the other 4) Wingtip popped open and had to be re-glued 5) Rear balsa wood support for Horizontal Stabilizer/Elevator broken on both sides, still attached but the cardstock is the only thing providing strength 6) Main landing gear is "sprung" meaning it sits a lot lower than when new, prop now hits the ground when wound up. With all the damage the RV-6 is still 100% flyable, actually flew it without any repairs with all the above damage in place. Now it is fixed, plan to keep it up on a shelf. First of its kind design for me. Mike
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Cardstock Property Tables and Terms Flying Cardstock Models http://www.papermodelers.com/forum/m...uers-projects/ Last edited by mbauer; 02-29-2020 at 06:04 PM. Reason: Mention damage to RV6 |
#59
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You are doing some great work on these flying machines. What you need is a bigger indoor space to test fly them.
Somewhere without so many things to smash into.
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~Doug~ AC010505 EAMUS CATULI! Audere est Facere THFC 19**-20** R.I.P. it up, Tear it up, Have a Ball |
#60
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Quote:
Yes, bigger. The warehouse these were flown at using about the last 70ft of the warehouse to fly. Size is 190ft x 120ft for a footprint. This is the only part that is usable for flying. Model uses about 20ft for take off roll. Plan to head outside if we get a calm day. Been cold and wintery here in Alaska, snowing at least 5" today. Might be awhile before able to head outside. That is ok, plan to have some models ready to go, I know these fly so that was the big reason why flew these inside. It worked well enough for first flights. Next RV-6 will test several issues, one being how big a model can be and still fly. (48" wingspan RV-6 50% complete) This new size is printed on Springhill Index 110lb cardstock. When comparing patterns for balsa to the pattern in cardstock, using 1/20" balsa weighs less than the pattern! This is a huge discovery. A small triangle piece of cardstock weighs .69gm vs., same size in 1/20" balsa weighs just .48gm. Lots more support with balsa! Up-sized the internal rubber band tube, been using a standard 5/8" I.D. rolled paper tube, now 7/8" I. D. tube will be used. The 5/8" style was shortened or lengthened as needed for each model, at 17" long in the 30" wingspan RV-6 model, it held up to the loads without issue! Some important testing on it will need to be done. Questions abound: 1) Will the larger diameter still work like the smaller diameter; not deform and tear as the rubber gets wound up tight 2) Now the length could be an issue, the longer one might buckle in the middle, this new tube is 28" long All the compression stress of the rubber band and flight loads on the model length wise go through this paper tube. The skin maintains the model shape, it is not carrying much of a load. Short building break is over, back to gluing. One thing is for sure about using cardstock, if the model "breaks" the cardstock is easier to fix. Pretty sure a stick and tissue model would have been a pile of kindling, when the RV-6 dropped from hitting the rafter steel beam, it crashed hard from about 25ft up. Hit it dead center in the apex of the beam, then as it descended it was still accelerating under power, the far wall saved it from a direct nose to floor hit. Mike |
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