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Messages - 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
Thanks for the encouragement, Gord.
 I finally learned something regarding the ROG takeoff situation (slow leaner here!). The following discussion is for my own benefit and perhaps for yours, Gord.

The above videos clearly show the problem I have been having, a combination of a questionable Thrust Vector (TV) mixing strategy and my slow reaction time. Just to make things more interesting, I avoid getting into using a Flight Controller, the objective being to do all the complex stuff within Airware, the Spektrum system which operates the DX9 and other DX-series transmitters. I am very happy with this latter decision. The former issues are correctable, methinks.

The one perfect ROG launch was due to my switching Flight Modes and thus disabling vectoring at just the right time, within a second or so of liftoff. The subsequent crunch was due to a completely unrelated issue - the plane normally flies like it is on rails once airborne and approaching horizontal, as the hand launches have proven.

 In Launch and Landing Modes, I have Elevator mixed to Thrust Vectoring (TV). This seemed like the right thing to do, as the motors have to be rotated almost vertically for ground clearance of the props and, secondarily, to provide immediate launch thrust. So, I have coupled TV into Elevator for this. The result is that the takeoff is extremely quick - sometimes, the machine does an immediate back-flip right off the ground. If I do get airborne, I have to immediately flip to Cruise Mode to cancel TV and have normal, pitch stable control. Similarly, in Landing Mode, with this coupling enabled, it is way too pitch sensitive. The coupling can still be selected in Cruise Mode via a normal switch, to perform its big trick, the wicked backflip(s).

 So, I reason that the solution is NOT to couple TV to Elevator for Launch and Landing Modes. During Launch and Landing Modes (in the latter, it may be left as switch selectable, as there is much more time to set up for a stable approach and landing).

 I will reprogram the Launch Mode, at least, so that we have full TV at low Throttle, gradually being reduced as Throttle is advanced. This will take a bit of tinkering, as we have to judge at what point the machine will have begun rotation, is likely to become airborne, will have prop clearance with the motors returned to align with the chord line, and then completely dump TV so that it can be flown out normally. This will give me lots time to move from Launch to Cruise Mode without any other distraction - as long as we have a high Throttle setting in the Launch Mode, TV is effectively off and the switch to Cruise will ensure that Throttle changes do not re-engage it.

 To try this, I may drag my poor, somewhat abused  Tailsitter Mk.1 out for another "kick at the cat can", rather than sidelining it and moving the gear to the new machine.

 If  one of my conscript videographers is available, I may even be able to document the whole sordid affair!

 If there is anyone else out there who is weirdly inclined to play with this kind of stuff, I can perhaps offer some help.Misery loves company? This plane is terrific in the air, the fully back-flips are something you will not likely see on anything else, the plane itself emerged from 2 sheets of Elmers foamboard and the only real complexity is in the DX9 programming, for which my SPM is readily available as at least a starting point, along with spreadsheet documenting all configurations and settings.
 

3
 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

4
Well, Taildragger Test Flight #2 was somewhat brief and anticlamactic. No video, but I learned something, so we can call it ... Success!

This one was much better. The art of taildragging is a bit daunting, so I enlisted the help of Flypaper to provide an assisted launch. Meanwhile, Cal ran the camera. Thank you, fellows!

https://youtu.be/11auB5eNfZM

5
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

6
FPV at KRCM / Re: Flying Crash Mystery
« on: August 11, 2017, 05:47:35 PM »
Hmmm ... doesn't sound like Tx issue to me ...
1) You have flown to much greater distances without any hint of problems.
2) Both planes went down in almost the same place. Coincidence?

Now, as for Rx problems ...
Did you have the same Rx in both planes? Same antenna orientation?

If not the same brand/model of Rx, are they both DSMX?

DSMX is practically invincible to outside corruption, from what I have read, except if some sophisticated deliberate jamming were employed. That is highly unlikely, even if the army was doing its thing to the west of us, in the DoD practice area.  If they were both DSM2, well then there is a chance that something bounced them (DSM2 only uses 2 channels, they can be close together and therefore more susceptible to interference than a frequency hopper like DSMX that uses a number of channels in its pre-determined pattern. With either of these, the chances of 2 different Rx/Tx couplings using the same subset of channels would be practically nil.

On second thought ... Flypaper suggested that you may have a loose antenna connection in the Tx. That may be the most likely cause, if you accept that the crash sites being so close is just a coincidence. Over th3 years, we have had a lot of planes go down in that region. Is it haunted?

You have a real mystery on your hands!

7
The testing continues, new learnings and some conclusions being developed.

The plane is now called Taildragger Mk.1, as it rests horizontally for launch, motors vectored about 45 degrees upward, ready to drag its butt vertically, then change to normal configuration. This actually works, as some others have discovered, and it forms the basis for my new project. The existing plane has been my training wheels, and I have learned a lot. I will leave tailsitting to things like my X-VERT and do VTOL in this manner.

 Two more test flights of Taildragger Mk.1 were done over the last couple of days. One was documented with video, which I may post sometime soon.

The first one was done with a hand launch, to sort out any trim issues and have some fun. This thing is an incredibly good flyer, very stable and yet will do some wicked unusual tricks. It will tumble around its horizontal axis if you enable Thrust Vectoring and then haul back on the Elevons. It will do some sort of flat spin, combined with tumbling and who knows what, if you start in slow level flight, pull up a little  bit, crank in full Rudder (differential thrust) hammer the Throttle and monkey around with the Elevons a touch. Yet, when you release everything, it comes back to normal flight.

Yesterday, I did a direct taildragger launch from the grass, It launched OK, but immediately swerved and whumped in. No damage to the motors, servos, etc., but it ripped off the one sponson. A few minutes with the Flypaper Welder, a.k.a. hot glue gin and it should be restored.

This was a successful test! Why? Because I learned something in that 1 or 2 seconds - something that has been at the heart of some difficulties on previous occasions. It is hard, or impossible, to nail the Throttle for launch without inadvertently introducing some differential thrust via the Rudder stick motion. Due to the way in which my system has to be set up (I use 8 Mixes to accomplish all that is required), I cannot implement Exponential on the Rudder function, so it is way too sensitive. Today, I will repair and have already set up a strategy of 3 Flight Modes. In the Launch and Landing FMs, the Rudder function will be disabled; it may or may not be enabled in Cruise Mode immediately after launch until just prior to landing.

I have also concluded that the Thrust Vectoring is too sensitive during Launching and Landing. Again, since this is mixed into Elevon functions (4 mixes required), there is no way to implement Exponential, As with the Rudder function, I want/need full Travel on those channels. So, I have implemented another way to calm things down, one which might be of use to folks who love the play with Flaps. Many are unaware that on the DX9 and many other radios, you can set Servo Speed. I played with different values for the TV servos and am trying 1.0 to start with. So, when you crank in Elevons, theTV servos also respond but slower and therefore smoother. I like it!

So, hopefully one more kick at the cat (or is it the can? I forget), with this plane. Then it may be retired, as I need the hardware for the new Taildragger Mk.2 development. I plan to document the build of this very simple undertaking. Materials and construction are minor components, the real work has already been done and resides within the DX9.

The DX9 programming which is associated with this project is extensive and complex. It is well documented via spreadsheet. At least some of this would be an excellent starting point for someone who wants to try out a twin-engined aircraft of any type, not specifically a VTOL. I may even decide to post the SPM and the spreadsheet documentation.


9
I set up my  2 Cheetah 2208-14 motors for testing. As I cranked them up and down quickly in speed, they sounded great. When I did the same thing slowly and then paused at various speeds, particularly in the under 4000 rpm range which is most critical to my use in the VTOL plane, here was no audible beat and the tach showed that they were perfectly synched! Good little fellows, methinks  ;D

This takes one possible variable out of my earlier concerns that the manufacturing tolerances in ESCs can lead to synchronization issues  ;D
I do think it is a good idea to use the same brand and model ESCs on any twin, if for nothing more than piece of mind - especially if you ever get into re-calibrating one or both of them, either deliberately or accidentally.

Incidentally, I had one good APC 8x4E prop. The other was the same but had tip samage, so I chopped off about 1/4 inch (the Flypaper Method for Propeller Modification/Improvement). Despite this disparity, all went perfectly well!

A couple of precautions:
1. When doing any kind of bench testing with props installed, make absolutely sure that your test system is totally secured and that the associated wires are kept well clear.
 
 2. As you may, like me, be operating a servo tester and a handheld tachometer  and ammeter while checking their readings, it would be very easy to get distracted or careless and ... enough said!

3. Do the testing outdoors. The 60 Hz lights inside will render your optical tach useless.

My test setup is a square chunk of wood large enough to bolt the motors onto, with about an inch or so of clearance between prop tips and clamped  in a Workmate type of stand.

10
 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 ...  :(



11
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)
   

12
This is the concept which attracted my attention:

https://youtu.be/9xjHCHR5_50

I have now flown my store-bought X-VERT a number of times, with vertical take-offs, transitions, full horizontal stabilized and unstabilized flights and vertical landings.

Now, back to my own Tailsitter!

I have decided to take a different approach to the VTOL modes. We are returning to vectoring the motors and eliminating the vectorons. This time, the motors will be vectorable to almost 90 degrees "up" and about 10 degrees down.
Takeoffs will be with the fuselage lying horizontally, motors vectored vertically to pull the nose up and lift the body, with transition then occurring rapidly by holding the motor thrust vector close to vertical while the fuselage rotates to inline with the motors and begins flying. This plane has the necessary much greater than 1:1 thrust to weight ratio. Landings would be the reverse of this procedure. Again, there will be no flight controller involved. I still have to resolve the issue of assymetric thrust, possibly due to motors not synching at intermediate portions of their range, resulting in hairy/scary launches.

Hopefully, testing will resume next week, along with video - disastrous or not!

13
Plans, Projects and Building Tips / Re: Hinging of Foamboard
« on: July 23, 2017, 11:17:57 AM »
Gary:
I don't know. looks tricky to me and you know I don't have much patience. There must be a better way. I like pin hinges, but they will pull out in time. I'm going to try different things till I get it right. Being a crasher, I need something strong. The fibreglass hinges tend to pull away.

The most durable has been the hot glue hinge, but also tricky to get right.

As for the foam seminar, that would be fun if you can find more than 3 interested parties. Count me in.
Reg

Well, thar be you, me and the Master - quorum! We sort of do this anyway, it's just another excuse to lend an air of legitimacy to it all.

As for that hinge technique, I really like it. I did a couple of them on scraps to develop the technique, perhaps not exactly as he did it, using a covering iron. I will try on my next Unidentified Foamy Object.

Now that my (store-bought) X-VERT is a complete success, I will get back to some work on my own design, perhaps even starting all over!

14
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!

15
Thanks, Dwayne, for your video work and your support. I am putting this project aside for a few days, thinking of the next steps and planning to try out my store-bought X-VERT tailsitter VTOL. Flypaper already has his under control ... sort of.

I have serious doubts about the vertical landing of my Tailsitter, as my brief try to hover at altitude was not very successful. Perhaps I will revert to the vectored motors approach of my Mk.1 plane. And, I have only used 9 of the 10 available mixes in the DX9, so who knows what is yet to be done!

Meanwhile, I found another homebrew design that makes more sense than mine, so I may shamelessly steal some of that fellow's ideas.

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