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Hello Hans and Chris,
Your work on the 162 is great! I am a big fan of early German jets...The PAF seems to be a redo of the Century jet because they both have the engine pod too flat near the rear sides and the extended turbine pipe at the back should be perfectly round with a sharp angle where it meets the fuse/pylon. But they have a odd shape and blend into the fuse below the line of the turbine..it is odd they they both are that way. So I suspect a common birth |
Latest blog entry: In flight
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Hi,
the new mill works! I prepared the baseplate and the scrifice slab (Can you understand me ?) until yesterday late night. A lot of drilling and thread cutting. Today I finished milling the deep-drawing mold/punch for the canopy. I started milling the two parts - now glued together - on my old mill still. Thatīs why you can see some mistakes on the mdf. (The blame lay with a defect bearing that needs to be changed now.) Chris. |
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Shortly, a bit off-topic:
My new monster mill was very busy already as you can see in the pics below. This is my Laird Turner Special, LTR-14, 1/3 scale. My most "skilled" cad project. It cost less than three hours to stick the fuseīs parts together. Incredible! Sorry for that self-laudation, but I was so fasinated while sticking all these parts together, not yet having used a single drop of glue, no need to file anything, apart from some very rare exceptions where non-rectangular parts grab into eachother. The legs are glued into the "slipway", thatīs all in the matter of glue. Iīve never built something similar, really. A fairly complex construction, to build up so amazingly fast and easy. Chris. p.s.: Sorry, one more time for my enthusiasm. |
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By the way,
I started a LTR-14 thread on German RC-Network. I simply wonīt find time to start another one here on RCGroups. Sorry. But Iīll post lots of pics on RC-Network for you! Promised. Chris. |
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Pics of the cockpit
Hallo
It time to bring some more pictures of my cockpit building. The stick and the rudder peddals are servo operating and the nose gear stearing has been prepared (0.5mm steel cable in an 1.8mm brass pipe). But look by yourself. |
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Hi Hans,
nice work on the cockpit. I especially like the quadrants on the side. Like ticketec I was wondering if you were going to clad the balsa but then thinking about the circumstances and design philosophy of the full size bird realized that a lot of the stuff in the cockpit may have been out of wood. So just how much metal was there in a Salamander cockpit? Dan Eaton |
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Hallo Dan, hallo Dave
Thank you for your interest. Until now, all parts are still removable and before they are permanently installed, the surface is processed accordingly. The question for the metal in the cockpit is of course justified. The seat is made of brass tubes and the seat pan, which, however, still do not like me correctly, is from 0.2 mm aluminum. The guide rails for the seat are made of aluminum so that I may at any time remove the seat to get at the underlying installation space for the fuel tank, servos and pressure bottle for the retractable landing gear. Also going from this room to the front pushrods are made of thin brass tubes and is running 0.5 mm steel cables to the pedals and to steer the nose wheel. What still needs to be installed is a tube in which the power cables are routed for dual receiver and supply for the turbine-elektonic. But one after the other. Hans-Gerd |
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Hyperlink to the French "Museč Air+Espace" |
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Hi all,
tonight I sanded the ruddersī tips. Thatīs not the kind of work I really enjoy. So I decided to leave shaping the nose to the mill ... Chris. |
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Dan,
sorry, I nearly forgot to answer. Milling the LTR-14 costs nearly a whole day. I use a 0.8mm cutter. So you can only feed very slowly. It is some 10 plates 1.20m x 0.60m, 10 plates 1m x 0.25m of balsa and several smaller plates or parts from G10, multiplex, plywood and so on. Depending on your skills design and construction need about ... hmm ... many many hours. Chris. |
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Hi all,
nice to meet you all again. No posts on the progress for so long, sorry. I was pretty hardworking on my gear-/lightcontroller demonstration panel. In the moment this acrylic model is finished by a good friend installing all the electrical and electronic components. Iīll show you what it is soon! Now, here are the latest news on the He-162 prototype: The gear is installed, at least for demo puposes. And the model is standing on its own feet. Everything fits very well. I milled all the remaining 3D parts and molds for the Heinkel. After some initial problems the new mill works stable and reliable now. Thanks to the perfect Sorotec support, where I bought the machine. The boss there does a good job! Best regards, Chris. |
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Hello
Also, I was not entirely idle. All cable connections from the front battery installation area to the rear are finished. Hose connections to the BFW are prepared and also the double valve has already found its position. Also, the sample tank is finished with a capacity of 2.3 liters (+500 cc Hopper tank should be enough for ne Frank TJ66) and has found its place on the pressure bottle for retractable undercarriage will be automatically locked by the way in the model through the insertion of the bottle. In addition, in the cockpit, we continued a bit and the seat I've changed. Will not be long and it goes with the planking going on so that the crate from the building board comes down and will be usable. As far as first times the last and latest news. greeting Hans |
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Hi Dave,
in the moment 6" dia is installed. It should be 6.4 or 6.5" to be scale. And, what is more, mine is much too rectangular in its cross section, it was designed for a modern jet obviously! Iīll insert one with an original round profile. Now here are the two pics I posted on rc-network a few hours before. This is (nearly) the state the Volksjaeger is going to be exhibited on the fair. Chris. |
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Wow, looking fantastic!
For the wheel, are you going to make something specific, or just buy something? You do know that the real salamander used Bf-109G main landing gear and wheels! so someone like sunshine modell und hobby http://www.sunshine-modellbau.de/ or maybe even AS-scaleparts 1/4 me-109 landing gear or wheels might work? http://www.as-scaleparts.de/8.html all in your part of the world Thanks dave |
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Yeah, youīre right.
since there are many fans of the Me 109 all around the world it should not be a problem to find good parts for the landing gear. Thanks for your links and advice! It is not necessary to design something specific for this He. Nearly everything will fit in. Chris. |
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Hi,
no, Dave, I did not find time yet. I will leave them as they are for the fair. Iīm sure Iīll find some nice wheels there. But I did a minor add-on to the Heinkel. Since the ESCīs high power wires are ducted along and pretty close to several servo cables I decided to shield these 10qmm leads in 8/7.1mm alloy tubes. Unfortunately it is very difficult (or even impossible) to ground electric potentials in an airplane! Anyway for the testing I prepared a "ground" lead to be connected to the battery minus. Does anybody have some experience in this kind of EDF specific questions? Chris. |
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Hi Chris,
I think you were wise to take that precaution of trying to shield those motor power wires. As for as how effective your shielding is I would think you'd be ok with what you did but it would be nice to know for sure. Normally, you want to provide a low impedance path to ground to drain the energy but as you said that's kind of difficult in an airframe. Do you have any friends with access to an oscilloscope? That would allow you to see the high frequency noise you're dealing with and give you a measurement on it's amplitude. Much easier to deal with a problem you can see instead of an invisible monster. Dan Eaton |
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In full sized aviation, what we do in order for the shielding to be effective, is the whole length of the wires must be encapsulated in a braided line, and then both ends of the braid must be grounded to earth. Seeing as you are sending 3 phase power down those lines there is no earth to ground to so it would be ineffective. the brass/copper tubes you have installed will also be ineffective.
I have flown everything from 127mm EDF on 12s, down to 70mm edf on 4s and what is the most effective way to trying to reduce potential interference is to twist the 3 motor wires together along their whole length. I've done this on all my electric models, not just edf (they are no different really) and have been fine with 2.4g radios. I would use twisted HD servo extensions/leads as well. how much twist? as the frequency is always changing there is no right answer. I know that for 400hz, you need 8 twist per foot to cancel it out Thanks dave |
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Putting each wire in it'sown (not grounded) tube doesen't make any sense. As mentioned by dave twisting is a effective way to reduce emission. Twisting and putting the twisted cable into a tube which is conected at on side to minus would work.
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Seems to me that even the specialist not agree on one solution. In data acquisition systems you are always grounding only on end to avoid the ground loops as mentioned by turbonut.
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Hi,
as far as I remember, when connecting both ends the potentials are compensating resulting in new/additional currents. It therefore depends how long/big such loops are to decide if to ground both ends or only one. In case this "new" effect (the potential compensation) counteracts the positive effect of a fast two-sided leakage to ground, then it would be better to only ground one end. Thatīs the theory. But, frankly, I donīt have any idea what that means for our concrete application in electric-driven rc aircraft Thanks a lot for your contribution. The thing is - We simply have to try out, and see! Chris. |
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The wiring looms on the aircraft can be very long. The airframe is 60m long after all. Maybe also for redundancy?
EVERY thing on Airbus's are grounded to each other and the structure. So not only the boxes, sensors, and shielding grounded, the hydraulic piping, even the toilets are grounded! Those aircraft are one big flying ground! it's a real pain actually. Thanks dave |
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Hi,
thatīs actually the way it is. You can hardly ground 60m long structures to one single ground point (star grounding). Depending on the frequencies/frequ. mix you expect as interference/noise it may still be more acceptable to get loops than having high resistance/reactance. Iīm working for railway safety assessment. E.g. grounding along long platforms is a serious topic. (I admit this is not the special area I work in ) Anyway it can easily be imagined that grounding to one point doesnīt make sence in this case. Chris. |
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