Turnigy Spacewalker half scale 168" 4.3m electric

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This topic is to record my build of what is likely to be the world's largest single prop electric RC plane. I have been using Tunrigy equipment with fantastic results for the past 3 years and this plane will be built with Turnigy equipment. It will be:
- 14 foot, 4.3m wingspan.
- 10.5 foot, 3.3m long.
- around 77lb, 35Kg.
- 14Kw Turnigy electric motors (2x 7Kw motors on a single shaft).
- Two 200amp Turnigy HV monster esc's
- 24 Turnigy Nano-tech, 3 cell, 5000mah LiPo's.
- Turnigy HV, titanium, 31Kg torque servos throughout.

The plane is a half scale version of a Spacewalker 11. I have designed the plane in AutoCad and laid out all the parts so I can get them laser cut. The costruction is a trussed frame, to look like the full size one and is made of cyparis, ply, lite-ply and balsa. The covering will be a full-size aircraft nylon material fixed using dope.

Photos and details to follow soon.... 

Edited by wolw - 16/Feb/2011 at 1:13am

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MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Topic: Turnigy Spacewalker half scale 168" 4.3m electric Posted: 20/Jan/2011 at 4:46am
	This topic is to record my build of what is likely to be the world's largest single prop electric RC plane. I have been using Tunrigy equipment with fantastic results for the past 3 years and this plane will be built with Turnigy equipment. It will be: - 14 foot, 4.3m wingspan. - 10.5 foot, 3.3m long. - around 77lb, 35Kg. - 14Kw Turnigy electric motors (2x 7Kw motors on a single shaft). - Two 200amp Turnigy HV monster esc's - 24 Turnigy Nano-tech, 3 cell, 5000mah LiPo's. - Turnigy HV, titanium, 31Kg torque servos throughout. The plane is a half scale version of a Spacewalker 11. I have designed the plane in AutoCad and laid out all the parts so I can get them laser cut. The costruction is a trussed frame, to look like the full size one and is made of cyparis, ply, lite-ply and balsa. The covering will be a full-size aircraft nylon material fixed using dope. Photos and details to follow soon.... Edited by wolw - 16/Feb/2011 at 1:13am

Blind Vision Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (DK) USERID: 52464 Forum Admin ADMIN Joined: 21/Oct/2009 Location: DK/Denmark, AMC Online Status: Offline Posts: 3804	Quote Reply Posted: 20/Jan/2011 at 5:05am
	Now that sounds like an impressive build, -looking forward to see it, and follow it.
	Doing some guerilla gardening... take a peek; http://www.facebook.com/groups/416558261701047/ lokal bustop infront of my flat

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 21/Jan/2011 at 7:12am
	I have been working on this project for six months now and I am going to put on here a complete build log of where I have got up to. This log was written as I was building and has been listed on another forum. I am now transfering to use this forum so will add all the details here. October..... I am just about to start building - the design is 95% complete, just the landing gear to do. My 1/4 scale electric Spacewalker 2 was flying in 4 of the LMA shows this year (my son Sam was flying it). We like it so much we have decided to build a half scale one. The full size is currently built by Serenity Aviation (http://serenityaviation.com/home/) and supplied as a kit.....so if anyone fancies building a full scale we will have the full set! Serenity were very helpful and sent me their drawings so I could get the scale spot on. The full size drawings were my starting point and once I had loaded them into autocad it took 10 seconds to scale them and then start desinging. Myself and Sam have been flying electric for 2 years now and have been using LiPo's from the start. We have developed loads of experience with them and fly everything from indoor 1 cell to 12 cell 4.5Kw aerobatics. We eventually homed in Turnigy equipment as being one of the best made money can buy. Now I know there are lots of stories from people who can tell you they had a "such and such" and it was rubbish, but usually we find when we ask for full design/operating details the reason something was "rubbish" was because the owner broke it. There is quite alearning curve and most users new to elec will have failures as they abuse various items. Siince we use Turnigy pretty much exclusively now, I started discussions about this plane with HobbyKing many months ago to see whether they would be interested in sponsoring an electric 38" single prop plane. Yes was the answer, so I now I can design around using 12cell Turnigy batteries.

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 21/Jan/2011 at 7:20am
	Here is the design data:

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 21/Jan/2011 at 7:26am
	Now that I have fully designed the model in autocad I have prepared all the shete materials ready for laser cutting. Ian Hull at SLEC is providing all th ewood and doing the laser cutting for me. After a quick lesson from him in how to format the drawings so that his laser cutter will work with them I have got them sorted. Here are a couple of examples: The above drawing is the wing ribs that are cut from 3mm lite ply and the �rings� are reinforcing fro around the wing tube areas. The �tabs� where the rib numbers are shown are also all individually sized such that when the wing is being built there will be 9mm of wing washout built in ie, the tab on number 14 is 9mm bigger than on number 2.

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 21/Jan/2011 at 7:53am
	Hinges for control surfaces While waiting for wood and glue to arrive I have been looking at linkages and hinges. My over 20kg inspector says commercial hinges are not up to the job so I need to do them some other way. I can see a few photos here and there on this forum of different ways people have been making hinges. Which is the best way? Let me know please. This is what I have made as a trial for the hinges on this plane. I will not have access from the wing end to slot a rod in and I am also planning to do the ailerons as 2 completely seperate surfaces on each wing ie 4 of them, so I can nicely split the control between receivers. The following is a Protech 3mm heavy duty clevis, which slots perfectly into 6mm (0.5mm wall) brass tube, which will then be glued into the wing hinge mounting blocks. The control surface side is a piece of 3mm aluminium plate with a 6mm sealed bearing fitted. This will be glued in place and �pegged� through the end. The hole you can see in the ally strip is just how it was mounted whilst in the milling machine. The control surface can now be fitted (and un-fitted) by the 3mm cap head screws.

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 22/Jan/2011 at 5:20am
	Servos For the servo loadings I have done calcs from first principals looking at mechanical loadings. I also then used some shareware for calculating the aerodynamic loads. The software gave lower loadings as below (and I did use rather an extreme max speed): The rudder has the highest loading and comes out at 33Kg.cm I have been thinking of using the new Turnigy 33kg.cm HV servos. These are a compact servo, only slightly larger than standard, with titanium grears, an all alloy servo body and work directly on 2 cell LiPos, which keeps the current lower. These have been extensively tested in 1/5 scale off-road buggies as the steering servos and have faired excellently. The issue with the use of these servos on a large scale plane is that I will need to test them first on another airframe. I have discussed this with HobbyKing and they are now sending me 10 of these new servos. I will install a couple of them on my sons highly stressed “Supernova” airframe. This runs on 9 cell electrics with 3x 3cell Turnigy 5000mah LiPos and a 20″x20″ pitch prop. For the Spacewalker I am splitting the ailerons in half so that there are 2 each side, with 2 servos, thus building in lots of redundancy. Two will also be needed on the rudder. I could get away load wise with one on each elevator half, but the large model inspectors over here don’t like ‘standard size’ servos used on thier own so I will either have to use 2 on each elevator half or a bigger 150gram size servo. I prefer to use the HV Turnigy servos as these can run directly from 2 cell LiPos with lower currents (because of the higher voltage).

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 22/Jan/2011 at 5:36am
	Elevators and Rudder The rudder and elevator on this build are very large curves. The stabiliser is approx 1400mm across. To make the curves for the rudder and elevators I have been using the laminating technique. I have done loads of laminating before, but these ones are bigger than anything done previously. I am looking for an 18mm finished width trailing edge, which will vary in thickness from 12mm to 6mm. There are lots of ways of bending balsa using water or NH3 (amonia), but the one I prefer is to use no liquid and start with wood that is thin enough to bend anyway. Although this means more layers it does not take that long done like this below….. This picture shows my strips cut ready. This time 1/32″ balsa and 18mm wide so I have spare to sand off later. I need 21 layers but need lots more strips as the curve is longer than the wood and need joins. Now I have cut all the strips to length and formed a stack of 21 layers, with all the joins in different locations. I am just starting to put on a layer of glue to the first strip here. I do the lamination by completely glueing the whole stack first, then picking it up and bending it round the former. I am using water proof white glue and I make sure that there is a nice uniform thin layer. On this picture you can see how the left half has been carefully ‘scraped’ to leave just a thin layer, the right half is before. Next the completed straight stack is picked up and placed onto my template. The thing I find now is that the glue on thin strip makes them very bendy, just like they had been soaked in water. The template has been cut 20mm smalled than the finished outline. The edge has been covered in plastic and then it is screwed to a base, also covered in plastic.

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 31/Jan/2011 at 8:28am
	Undercarriage I have now finished the undercarriage design and will be making it from SS tube, TIG welded together as a faithful copy of the full size. For the wheels I noticed that TNT sell alloy 8" wheels but 2 problems with these. Firstly they are not scale and secondly would cost over $400. Hence now started making my own. I found that on Ebay you can buy a set of 4 8" wheels for just �20..... Each wheel weighs 998grams. The hub however is 568grams. Once taken apart I have got inner tubes and tyres ready for some alloy hubs�. The alloy hubs will be 2 piece, screwed together with small grub screws. The axels are 15mm SS tube (scale) with 21mm OD bearings. So far I have machined one hub, but not yet parted it into its 2 pieces, so it is curtrently 3mm (parting tool thickness) wider than it will be when finished. I have left it whole for now because I want to drill and tap the small holes first�.. You can just see the flange of the outer hub inside the bore below. that flange will be parted off with the outer half of the hub. Current weight of the hub is 356grams, but this will be lower when parted off and with the addition of some large holes drilled through the centre.

MeMeMeMe69 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum (GB) USERID: 269904 Bargain Addict! Joined: 14/Jan/2011 Online Status: Offline Posts: 79	Quote Reply Posted: 31/Jan/2011 at 8:37am
	Wheels Progress has been a little slow as my back was bad and kept me flat for 5 days, then just as I started to saw a piece of 6" aluminium bar to make another wheel hub, the motor on my 1960's power saw gave in. Hence as well as the 6" bar, you can also see a nice new motor below..... Anyway, managed to finish the wheels now. Split rim ally hubs with 20mm od, 15mm id bearings at either end. I was going to add a ring of 5 holes to lighten the hubs further but the total weight assembled, with inner tubes and tyres is only 880grams anyway..... Today all of the cut wood arrived. This has all been provided by SLEC (Ian Hull) and is fantastically cut. This lot is from 6mm ply, 3mm ply, 6mm Lite ply and 3mm Lite ply. It has been cut using SLEC's CNC miller and is superb. The finish is excellent and accuracy is spot on. Just look at all those little pieces....all I need now is a bigger dinning room so that everything would fit ! Oh, and that is my son Sam's new Eurofighter in the background - it is currently being converted to 12 cell EDF with a 5Kw motor....what else are dining rooms for? And here is a wing rib (on top of an 8" wheel). The wing will use a main spar that is a built up box the same as its big brother. There will aso be two 50mm wing tubes.