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Topics - Deerslayer

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1
Buy, Sell, Trade or Give Away / For Sale - Senior Telemaster
« on: Today at 05:32:44 AM »
 This is the large version of the classic Telemaster. It is legal for, and has been flown at, several Giant Scale event.

 An extremely docile aircraft, yet it is fully aerobatic. Takes off and lands in almost zero length.This would be an excellent entry level plane for anyone wishing to try giants.

 It was built from a kit, with several modifications, including 2-piece wing and detachable tail for easy transportation in a small car. The design calls for a .61 size engine, but this one sports a dynamite OS 120 4-stroke engine (could be easily converted to electric). It has fully independent Flaps and Ailerons, plus a servo and dual purpose release mechanism suitable for banner or glider towing. Candy drops? - it's a natural! All servos are high quality, high torque metal gear. Any radio of 6 channels or more can be used (receiver is not included in this sale).

It flies well on wheels or skiis (snap-on Coroplast ones provided). Rear fuselage has been strengthened in critical area for possible float attachment.

For $200, it is yours!  ;D

2
 Thank you, Wilf, Harold and Terry for your assistance during a very interesting series of tests. Here is the product of your efforts - the Ups and Downs of flight testing this bird. Having video is very useful, as I can run it in VLC, slow motion and stop it, to see what happens during the most critical second or two of a launch, for instance.

 There may or may not be more flying of this machine, as it has undergone some sessions with the glue gun and the foamboard itself is getting sort of punky due to the paper detaching. I think that we may have gone past the Flypaper Golden Ratio of hotglue:foam, so this may be the end of my work with this one. The next one is radically different, still a taildragger wing, twin-engined, vectored thrust but much simpler. It will be much easier to get going, due to my experiences and learnings to date, plus the extensive programming of the DX9 which will be essentially unaltered for the new machine.

 Meanwhile, rumour has it that there may be one of these beauties incubating in the fevered mind of Flypaper, or it may already be on the operating table! Go Gord, Go!

So, here is the whole sordid affair:

https://youtu.be/YebpBz2wan4

3
FPV at KRCM / New FPV Camera from Lemon
« on: August 15, 2017, 07:39:45 AM »
 Very interesting! This was just announced.

 For those who are not familiar with Lemon, they have a lot of great products. I have a number of their DSMX receivers, receivers with integrated stabilizers including the latest Stab+. Testing done by outside RC and electronics experts have shown them to be unmatched in range. A number of others in the Club are also Lemon users.

 The designer is from Vancouver and has terrific support, which he reciprocates, amongst the Lemon user community. He normally provides samples of the latest items to a select few to thoroughly test and document. The Lemon manual for the original stabilizer and the Stab+ were both developed by a a pair of flyers - one in the Ottawa area, another in New Zealand - and have addressed all comments and concerns throughout the lifespan of the products, with the developer's total support. In fact, when you order one, you are provided with the link to that manual and other information on RCGROUPS.

  This tiny FPV setup will undoubtedly live up to the standards of all previous offerings. (I already have too many things sitting in boxes, awaiting installation in carious flying things, so I hope that someone else bites on this so I can at least see one!) 

http://www.lemon-rx.com/index.php?route=product/category&path=80

https://www.rcgroups.com/forums/showthread.php?2940390-The-official-Lemon-4-1g-VTX-Camera-thread#post38105806

5
 Have you ever seen a YouTube of an aircraft (or anything else, for that matter) and wanted study or to to build something very much like it? Perhaps this can help:

You may just want to see some detail about how the structure, or some component or subsystem, is built. Or, you may want to view various control actions in stop motion. Then again, you might just want to get some approximate measurements, such as the wing's aspect ratio tail and nose moments, powerplant placement, or to figure out what airfoil is used.

 There are several tools which can make this happen, and they are FREE! You can used them from a PC, an Android tablet or Android phone.

 One good YouTube downloader that is available is http://www.clipconverter.cc/  which takes the YouTube URL and converts the video online to your selected format (I selected MP4) and saves it to your device.

 Now that you have an MP4, you need a good viewer.

A few years ago, I discovered VLC. It is available free for PC and Android. I initially put it on my desktop PC, a laptop PC and my Samsung Note (Android) tablet and eventually on my Samsung (Android) phone. It is a terrific piece of software! My first use was to take  the videos which my Mobius camera had recorded aloft on various models and simply view them. You can alter the speed of playback, pause at any time, grab a frame as a snapshot. etc.

So, now that you have found a really good YouTube that depicts the various things that interest you, do the conversion to MP4 and bring that result up in VLC. Run it, slow it down, find suitable frames, snapshot them and print them out.

If this all works out well, you can sit down with a pencil and suitable drawing instruments and begin to mark up and scale the drawings. In the case of something I am working on right now, I wanted a plan view, side view and some details on vectoring motor mounts of a VTOL plane. As well, I ran through in slow and stop motion certain aspects of his flight to see what he was doing in the combining of elevons and motor vectoring during takeoff, cruise and landing.

Even if you are not in the building mood, this overall approach can provide some interesting information on various things. For instance, every once in awhile some "amazing" video shows up which purports to show an unbelievable action  :o. Wow! The internet goes bonkers, the thing gets passed around a gazillion times and the crowd is awestruck  :o  :o . Sort of like some of my, and Flypaper's, incredible achievements in aviation?  8)) However, if one cares to take the time to grab off said video into an MP4 and run it through VLC, the fakery can be easily spotted. One that comes to mind from awhile back is the large aerobatic airplane losing one wing and yet landing sideways :o :o :o :o (Yah, like that could really happen ...  :(



6
Let me tell a tale or two and offer something that may help someone else.

I have limited experience with twin-engined planes. My first was a Corroplast contraption, inverted V-tail, two OS LA15 engines. I created this to learn something about twins at lowest possible cost and minimal pain. It worked out very well, I spent many hours flying and hovering my effort. All I had ever heard about twins was that it was SO important that they be synchronized at all times! Well, it ain't all that easy, even if you break out 2 brand new engines, run them a couple of minutes (my normal break-in procedure), strap 'em onto somethin' and go flyin'.

In this case, the engines had very different histories. So, I fired them up and began to play. I could get them to fast idle reasonably close and even reach near synchronization at high end. I could either try to get them matched in mid-range or at the other two ends, but not across the whole range. It turned out to be of little issue, as I had designed the machine with great rudder (ruddervators, actually) authority in order to strongarm out of any unwanted yaw due to mis-matched power systems. It turned out that even that wasn't a big deal. What happens is that the engines seem to approach closer to sync under flight loading.
Good stuff!

On to electrickery! My first twin electric was/is my own design - Tailsitter Mk.1 and Mk.2 The concept is a VTOL flying wing with twin engines, not using a Flight Controller, just relying upon my DX9, brute force and dumb luck to get the job done.

In my flight testing of these 2 Tailsitters, I had very hairy vertical takeoffs, and hovering or vertical landings were way beyond their capabilities.  Hand-launched horizontal takeoffs were OK. I knew what the problem was, but not the root cause. At cruise, everything was fine and you could hear that distinctive tone of well-synched motors along with no rudder requirements. (There are no rudders, yaw is controlled by differential thrust of the motors, as mixed from the Throttle stick). Changing from a low or medium speed to higher Throttle caused severe yawing, due to unwanted differential thrust from the motors.

How do you know if 2 engines are in synch? Use a tachometer, or perhaps just listen. You will learn to detect the beat frequency when two sources are out of synch; it gradually decreases as the sources approach synchronization, and disappears if the frequencies match. On the ground, you can use a tach. Or, as I also did, mount your plane on a turntable and see how it responds to Throttle inputs. I have a turntable from an old microwave oven; an old phonograph turntable would be great, as well.


The big problem here was that the 2 engines would not respond identically as they are run up. I went through a lot of effort to to understand what was going on. ESCs? identical. Props? as identical as can be claimed.   It should have been obvious. Some dumbass had two slightly different motors on the thing! Now, I wonder who that could be?They were both 2208-14 motors and looked pretty much identical. Finally ... finally ... I realized what was wrong. One was a Cheetah 2208-24 (laser engraved onto the rotor) while the other was a BHP 2208-14T (it said so on a little sticker on the rotor). The former responded quicker  and more smoothly to power change than the latter. D'oh!


As part of this effort, I set out to test motors. In hindsight, I would do this before installation on an airplane, as I always do for my servos.

Here is the simple approach:
1. Bolt the motors down onto a piece of wood or your workbench, with suitable props attached.
2. Power the two ESCs via a Y-connection from a common LiPo.
3. Use a Y-connector to join the Throttle leads from the ESC. In my airplane(s), I avoid Y-connectors like the plague and on a twin you want/need separate channels for your throttles.
4.At some point, pull the Positive (RED) wire out of one of the connectors and tape it back out of the way. This is very important, both for the test setup and in the airplane.
5. Connect your servo tester to this common Throttle. Mine has a digital read-out of pulse width and a potentiometer to control that output. Mine can provide outputs of the typical range - 1000 through 2000 microseconds - which represent -100% through +100% on most systems.

Now, you have a means to control, hold and record RPM at any point in the power range while you check and record the two motors' RPM with your tach. As well, you can listen for synchronization (no beat frequency) or imperfect synch.  As others have discovered, even if you buy identical motors and ESCs, there may be some minor variations between the two systems. You could also measure current at various settings if you have an ammeter setup handy.

In my case, the Cheetah motor was very smooth in acceleration and held its RPMs close to constant at any setting. Not so for the (cheaper) BHP motor - it accelerated unevenly and wandered quite a bit. These motors are AC but  NOT synchronous motors.
 
The End
(at last)
   

7
Plans, Projects and Building Tips / Hinging of Foamboard
« on: July 23, 2017, 06:45:23 AM »
If you don't check in to the Flitetest site from time to time, you are missing some neat stuff. Somewhere in there, I saw the following idea and tried it out on some scrap. It is simple and easy and really works well! I doubt that one would ever break such a hinge, as it has the 2 paper layers sandwiching the minute foam layer at the joint line, yet it is as flexible as a taped or glue film hinge, in my opinion. (Perhaps we should add this into the Flypaper College Of Aero-Nut-ical Knowledge textbook?) Remember, there is more than one way to skin a cat - not that I am into that kind of thing.

https://www.flitetest.com/articles/ironed-foamboard-hinges


I wonder - should we be having the occasional seminar out at the Toyground, during our winter playdays, on some of this Foamology? Of course, it would be  FCAK certified!

8
Here is a little video I cobbled together for your amusement.

My overall objective was to create a VTOL Tailsitter which would use only the DX9's incredible programmability and a Lemon Stab+ receiver, cheap HK servos and a couple of sheets of Elmers foamboard. Stabilization and self-levelling were available, and although I tested each briefly, neither was otherwise employed.

I got a lot of flight experience and several more ideas from this flight. My Mk.1 version also flew without incident; however, I was not satisfied with a couple of aspects of its design and handling, so along came Mk.2.

In another, yet to come, video, I have some background on the project and demonstrate some of the technical aspects.

So, here it is:

https://youtu.be/FsS9Zsh-NR8

9
Plans, Projects and Building Tips / Fun Cub Gear Mount
« on: July 12, 2017, 06:32:17 AM »
Cliff designed a really nice mount system to replace the notoriously weak plastic one. Two drawings and a picture are attached. Do not be scared off by the detail and dimensioning. Just print out the drawing, stick it onto some suitable material and start cutting. Of course, someone who has a laser or other cnc  system could whack out a slew of these things and create a major product line, becoming very wealthy!  8)

Thanks, Cliff!

10
 I have been following this development for quite awhile.The Perlan project home is at http://www.perlanproject.org/

 Back in my soaring days, I longed to do wave soaring. Once, at Sugarbush VT, I was able to ride the wave, but not to a very high altitude. It was pretty exciting, nevertheless. The tow was quite demanding and violent, as we climbed through the rotor (that is where many aircraft have been taken down in mountainous regions when a wave is working and they encountered the rotor). I was a very inexperienced pilot, only a handful of flights past solo and it was a bit sweaty!

 Then, as we entered the wave, I released from the towplane and everything got quiet and smooth; he dove back down through the mess to pick up the next flight. No sensation of climbing, apart from the variometer showing about 2000 ft/min, as I flew pointed upwind. The winds aloft were in the 50 mph neighbourhood, so you could set up at that sort of airspeed and have 0 groundspeed. You just sit there and ride the wave, watching the vario and keeping track of where your landing area is.

  My flight was cut shot when cloud started to develop below me and I had to find a hole to let down through. Altogether, a flight that I remember in great detail some 45 years later. In those days, Paul Bickle held the world altitude record of 46,000 ft., in the mountain wave at Bishop CA. That record stood of decades.

 So much for all of that! Now, on to the real flying.

The following is an article from Aviation Week:


Airbus
The Perlan 2 stratospheric glider has arrived in Argentina as the Airbus Perlan Mission II team bids to set a new altitude record for sailplanes.
The pressurized Perlan 2 is designed to reach 90,000 ft., but chief pilot Jim Payne is hoping to reach 60,000-65,000 ft. this year, enough to beat the record of 50,727 ft. set by Perlan 1 in 2006.

Perlan 2 arrived by ship in Mendoza, Argentina, and on July 2 will begin the 2,600-km (1,600-mi.) road trip to El Calafate in Patagonia. From there the glider will be launched to ride standing mountain waves—air currents formed by the Andes—to successively higher altitudes.

The two-seat aircraft is designed to use mountain waves that reach into the stratosphere to achieve wing-supported flight at higher altitude than any previous aircraft, unpowered or powered. This becomes possible when mountain waves interact with the polar vortex.

Perlan 2 made its first flights from El Calafate in 2016, but was late arriving in Argentina and missed most of the winter season—one in which the polar night jet was weaker than usual. Since returning to the U.S., the aircraft has exceeded 30,000 ft. in flights from Minden, Nevada.

As the glider is expanding its flight envelope as it flies, altitude will be increased in increments of 5,000 ft. At each new altitude, a flutter test will be conducted using exciters built into the wing. If the results match the aeroelastic modeling, Perlan 2 can proceed to the next altitude.

Payne dose not expect to reach 90,000 ft. during this season. “The conditions are only right for a few days a year, and some years not at all,” he says. Ahead of this year’s flying campaign, wind speeds have been increasing in the stratosphere—a promising sign, he says.

Mountain waves would normally not extend above the tropopause, but in winter near the poles they can join with the polar night jet so that wind speeds keep increasing through the tropopause and into the stratosphere. As long as wind speed is increasing, Perlan 2 can keep climbing, Payne says.

Perlan 2 is similar in design to an Open Class competition sailplane, but with a larger wing area and an airfoil optimized for high altitude. It is unique in being pressurized. Perlan 1 was not, but it was hard for pilots to control the glider once their pressure suits had inflated and stiffened.

Pressurization required careful design to prevent leaks, but has been successful, Payne says. Nonetheless, a 115 ft³ scuba tank is carried to replace any air that does escape. Air and battery supplies are sized for an 8-hr. mission. The nominal mission is a 1-hr. tow to the waves, 3-hr. climb and 1-hr. descent.

Perlan 2 has been modified and upgraded since the 2016 flights from El Calafate. This includes adding heating for some systems because of the very low temperatures at altitude. Also the glider can now be flown unpressurized at lower altitudes to prevent the buildup of condensation early in the flight.

The glider is flown at its minimum sink-rate speed of 40 kt indicated airspeed (IAS) and climb/descent rates as high a 2,500 ft./min. have been seen in mountain waves. The allowable speed range at high altitude is 38-54 kt IAS—the latter equating to Mach 0.62 at 90,000 ft. because of the low air density.

In case the crew needs to descend rapidly in an emergency there is a drogue chute in the tail that will bring the glider down at 80 kt IAS. There is also a ballistic recovery parachute to bring the fuselage and crew down safely if the wings break off. This is safer that trying to bail out, Payne says.

Airbus is sponsoring the Perlan 2 mission and providing engineering expertise. One reason is the opportunity to explore the upper atmosphere. “With time, aircraft will have to fly higher” as air traffic grows, says Ken McKenzie, senior vice president of strategy and development of Airbus in the U.S.

11
General Discussion / Amazing 3D video at Huckin' In The Valley
« on: May 29, 2017, 06:02:03 AM »
There is more stuff over in RCCANUCKS but this is the one that really got me! Oscar quality  8)
https://youtu.be/OrePaMm2XpA

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