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Marty d's CH-701 build log


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As I spend most of my computer time (my wife may argue that the word "computer" could be left out) on this site, I thought it would be a good idea to transfer the existing content from the ZENITH.AERO site to here. Don't get me wrong, zenith.aero is a fine site and I use it as an info source when I'm trying to figure something out, but this is my "virtual" home.


Hopefully this will be along the lines of similar build logs done by Head In The Clouds, Bexrbetter, Kyle Communications, Skee etc. I've been inspired by yours, maybe in some small way this may help someone else who's plans building (or at least serve as a warning that they should go buy a kit instead!)


Please feel free to comment, I would like it to stay mainly on topic, but I know how these things go...!


Looks like I started the zenith.aero blog back in 2010 so there will be a disconnect between when the content is posted here and when it was originally posted. Apologies for this.


Cheers, Marty



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originally posted 31 March 2010


I bought my aluminium and steel from Performance Metals (NSW) around a year ago, March 2009. Very impressed with the service from Performance Metals - they delivered quickly, the sheets were very well packed, and the Chupa Chups hidden in the package were a pleasant surprise!


After picking up the package from the Hobart docks, I built a set of 5 racks topped with a worktop. The logistics of building racks to hold 12' x 4' sheets, and being able to access them, was challenging... I finally worked out that the best way to do it was to build the racks from the floor up with the aluminium placed on them as I went. Access is to the short ends of the sheet, via low doors in the outside wall of the shed. To get a sheet to the workbench, I just open the doors, pull out the sheet and loop it back over on to the top of the workbench. I'm even considering building a simple roller out of an old hot water cylinder surround to make it easier to move the floppy 16 thou sheets.


Anyway, life gets in the way a bit - dozens of projects around the house meant I haven't had a chance to do anything except drool over the plans. However, coming into winter I plan to start building, probably with the rudder. Using CAD I've drawn up the rudder ribs and printed them off at 1:1 scale. I figure it's probably easiest to glue them to MDF and cut out the forms with a scroll saw.


Had a bit of luck the other day - met a bloke nearby with a sheetmetal fabrication business - with a nice big guillotine and bending press. Might be the way to go with all those angles...


If there's any 701 builders in southern Tas who can offer advice, hints & tips, I'd love to hear from you.


Thanks, Marty



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originally posted 28 September 2010


Finally bit the bullet and started. Drew up curvy bits such as wing, stabilizer and rudder ribs on CAD. Printed them out 1:1 scale and traced them on to the 6061-T6. Only done the 0.016" bits so far (oh and the 0.025" spar webs), but it was good to finally get some aluminium out and start work.


Question now is what the best tool is for long cuts. 300mm shears? Nibbler? I know for damn sure I won't be making 12 foot cuts with aviation snips!




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originally posted 24 November 2010


I bought Jon Croke's excellent DVD on scratch building, which gave me heaps of ideas and methods that I probably wouldn't have thought of myself.


Made a bending brake just out of a hinged piece of Tas Oak on the side of the workbench (with another piece on the top which has an aluminium strip screwed to the edge with a 3mm routed edge for bending). At the moment I just screw this to the workbench when bending something, but have just bought a very stiff length of square section extrusion which will allow me to clamp the bending edge down instead.


I cut out all the parts for the rudder, bent, drilled and clecoed them together. As per the DVD I made forms out of solid timber (good old Tas Oak again - 20mm flooring) but as I haven't got a vice yet, clamped them to the workbench and bashed downwards with the rubber mallet. This seemed to work pretty well, even with the tight radius on the tip rib.


While I was making forms, I made the forms for the rear wing ribs. Because of the width I couldn't use the boards I'd used for the rudder ribs, so I faced them with Eco Ply which I glued and screwed to scrap particle board.


I've started work on the elevator ribs forms now. Before I finish the rudder skeleton I want to corrosion-proof each part. A fellow builder here in Tas told me about a Savannah he bought for parts - 2 years old and heaps of corrosion in it.


One thing I have realised on this build - you don't need a whole lot of expensive tools to get started, in a lot of cases brute force & ignorance is enough...



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originally posted 9 December 2010


Cut out the 0.025 stab rear spar & the elevator spar (the Olfa knife certainly makes it easier!)


I then came across a problem - my home made bending brake is only about 1300mm long, and the spar is 2220. However, by taking it slowly and bending a few degrees at a time along the length, I got both edges done.


Looking forward to forming the stabilizer ribs and putting it all together.


Oh, received my riveter heads back from Zenith too. Can't wait to pull some rivets!



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originally posted 1 January 2011


Formed all stabilizer ribs, front and rear spars (and their doublers). Drilled and clecoed the whole assembly.


Still trying to source Zinc Chromate or Cortec, so can't actually rivet anything until I've got that.



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Originally posted 19 January 2011


Over the last couple of evenings I got busy - cut and bent the rudder skins, marked, drilled, clecoed, drilled, unclecoed, trimmed... and today I deburred, Scotchbrited, primed, and finally riveted everything together.


It was a pleasure to use the air riveter for the first time - I may never pull a rivet manually again...!



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Originally posted 22 January 2011


Fabricated and installed the upper mounting points. Also riveted the control horn/lower mounting point, and the upper & lower spar fairings.


Stupidly I decided to hand rivet the upper mounting points... "It's hardly worth starting the compressor for 8 rivets..." yeah right, they're A5 and take a bit more force than A4's. Wised up and air riveted the rest.


That should be it for the rudder apart from trimming the nose skin to clear the elevator. I'll leave that until the fuselage is done.



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Originally posted 29 January 2011


I borrowed some flanging dies from a fellow 701 builder here in Tassie (thanks James!) 5 minutes work with a car jack and the holes were done.


Assembled and riveted the stabilizer skeleton.



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Originally posted 26 February 2011


Stabilizer complete.


I've been too busy building to bother adding posts! Anyways, cut out the skin, drilled, made the front and rear supports, clecoed the skin back on, marked out the front slot and slots for front supports, took the skin off, cut the slots, deburred everything, painted joint areas with primer and riveted the supports (7H2-6 and 7H2-7, I think they are) into place.


Today I put the skin back on (obviously had to cleco the curved side first, in order to slip over the front supports), clecoed it all, then with the assistance of my 2-year old son, riveted it all together. Reasonably happy with the result - as other people have said, the rear edges look a bit ripply - but hell, I'm not building an FA-18 here!



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Originally posted 17 May 2011


Currently on holiday in Bendigo (Vic, Australia) so dropped in to Bendigo Airport where Allan Barton has his beautiful 750 and 601. Allan very kindly took me up for a flight in his 750, which has inspired me to redouble my efforts on my scratch-built 701.


The plane flew beautifully, especially impressed with the digital instrumentation and "professional" extras such as carby heat, boost etc.


The aircraft is surprisingly roomy with the bubble doors, which I'll be getting too. I also like the way the 750's trailing edges are folded instead of soft riveted - I'll be changing mine to that method too, as well as including a full length electric trim tab on the port elevator.


Many thanks to Allan for the flight, his patience with my endless questions and for inspiring me!



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Originally posted 6 June 2011


Just spent a pleasant couple of hours down in the shed, making the elevator rear ribs (including a modified one for the side with the trim tab), and elevator rear channel.


Very glad I've got a wood heater in the shed - when I came back to the house I noticed the cars were iced over and the grass was considerably more crunchy than usual underfoot!


Didn't take the camera with me but will take some pics soon. I'll take the elevator spar to a sheet metal worker up the road to have the flanges bent, rather than depending on my wooden brake.


It's times like this I'm glad I'm scratch building - you get a sense of achievement when looking at a pile of parts you've made yourself.



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Originally posted 13 July 2011


Finally got a chance to see my local sheet metal bloke, so got him to bend some pieces - the elevator spar, trim tab spar, and the trim tab itself. He did a superb job on the trim tab - bent it up from one piece of 0.016" with 3 bends. Note that the trim tab assembly on this 701 is based on the 750 style - full port elevator span, inset into the trailing edge. (I believe the 701 tab is a flat plate hinged to the existing soft-riveted TE - correct me if I'm wrong!) Anyway, as I've said on other posts, I think the 750 style trailing edges are far better looking (and easier to make) than the 701 design.


Got into the shed for a few hours last night and did some drilling and clecoing - got the elevator skeleton mostly clecoed together. The trim tab looks good sitting in the skeleton, just got to find a supplier of piano hinges locally that stocks aluminium ones. (I did order one from Zenith, until they told me that the postage on this $21 item would be $108!!)


I also bought the trim servo/linkage/wires etc, along with the welded hinge pins.


Quite looking forward to making the skins now and getting it all together!



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Originally posted 29 July 2011


A good evening in the shed tonight!


I'd been having difficulty sourcing a suitable piano hinge for the trim tab. While the Zenith one is entirely reasonable at about $21, it would have cost $108 for postage to Australia.


Finally tracked one down locally today - it's stainless steel instead of aluminium, but because of the thickness (about 0.025") it's light enough for the purpose. I intend to well and truly coat it with an anti-corrosive paint to avoid any corrosion problems where it meets the aluminium.


I cut it to size (935mm - although it's inset into the elevator as per 750, it's going on a 701 so the elevator is shorter) and drilled it to the trim tab side as per photos. Couldn't be happier with the result, it moves freely and when clamped to the trim tab spar, meets nicely at the bottom at full deflection (not that it will ever get that far!)


I'd previously coated joint areas of the elevator skeleton with primer, so fitted everything back together and clecoed it all. Very happy with the evening's work!



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Originally posted 30 July 2011


After pulling my air riveter to bits and removing the 6 jammed rivet pins stuck in it, I riveted most of the skeleton together. Didn't rivet the hinge pins, thought it might be easier to remove them to drill the holes for the split pins...


On to the rear skins next - can't wait.



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Originally posted 3 August 2011


Had a good weekend - on Sunday I cut out & bent the rear skins (made them a bit oversize in span so I can cut the ends to fit), drilled and clecoed them to the skeleton on Tuesday evening.


Yesterday I had a couple of free hours, cut out the front skins and got one taped on.


I love front skins. A simple rectangular piece of metal, give it a bit of a bend, and all of a sudden you've got a complete airfoil shape. Fantastic!



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Originally posted 8 August 2011


Over the last few days I've continued working on the elevators. Drilled all holes and removed skins from skeleton.


After some measuring and muttering, I carefully cut out the trailing edge of the port rear skin where the trim tab goes. Reattached the skin and mounted the tab and hinge, drilling through the skin, hinge and tab spar. Turned the elevator over and drilled the bottom skin to tab spar as well.


Trim tab looks good in the slot and moves freely. The side gaps are 2mm and the TE lines up nicely with the elevator TE.


I made a couple of 0.025" doublers for the narrow sections of trailing edge either side of the trim tab - being made of 0.016", the skin is prone to creasing there. These doublers fit under the skin and have 2 rivets top and bottom through skin, doubler and rib.


My brother in law Jim (electrician) came down yesterday so I got him to solder the wires from the trim tab servo to the 19' cable that goes through to the instrument panel. Very neat job and colour-coded heat shrink over the joins.


Located the servo to the upper skin and drilled the mounting holes, also cut out the inspection hole in the lower skin.


Planning to get back into it tonight, there's still a heap to do before riveting!



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Originally posted 9 August 2011


Last night I trimmed skins to size, deburred, cut out slot in trim tab spar for control rod and filed all the edges.


I'd seen other people use a Dremel tool to do the control slot - I don't have one (used to, think I lent it to someone!!) - but found that a step drill, used carefully and with wood clamped behind the aluminium, worked fine. Even on the 0.016 skin.


I also made a doubler (just 0.016) for where the trim servo is riveted to the top skin.


Still need some minor trimming of rear skins - they overhang the spar by about 2mm so will cut them down to size. After that, I need to get everything back together and make the control horns & centre hinge point. Then disassembly again and priming before final riveting. Always takes longer than you think it will!



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Originally posted 23 August 2011


Elevators finished!


Well, as much as anything is finished before final assembly.


I drilled the 5/64" holes in the outer hinge pins, assembled the centre hinge point (bloody hard to cut a 2.5mm length of 1/4" tube for the bushing!) - got it all together and swinging freely.


Only thing really left to do is source some sheetmetal screws and put an inspection hatch over the hole in the bottom skin where the trim servo is.


I sat the whole assembly upside-down and wiped the lower surfaces with some turps to remove all the bits of glued-on tape residue, before taking some pics.


Pretty happy with the trim travel, but might adjust so that I get more down than up (ie more elevator UP force than down). It's about even at the moment.


It's nice to sit back after a component is complete and enjoy a FIGJAM moment. I'm just impressed with the plans for this plane - how it's possible for a rank amateur with no previous sheet metal experience to make a couple of components, 2.2m long, with 3 hinge points - and have them meet up correctly! Well done, Chris Heintz.



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Originally posted 3 September 2011


With the tail feathers completed it's time to crack on with the next item (in order of increasing difficulty) - the wings.


Started by cutting out the rear rib blanks. I tried the router method described in the Homebuilt Help dvd - unfortunately only got half way around when the bit stopped cutting and jammed. Not a total loss though, the plywood templates are still useful - now I drill and screw the template through the aluminium onto the workbench, and cut around it with an Olfa knife. This method is pretty quick too.


I went through the plans and made a list of parts from the wings, slats & flaperons which require bending. I'll cut them out first, mark the bend lines and angles, and take them to a nearby sheetmetal worker for bending.



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Originally posted 29 October 2011


Working on spars.


Got the root doublers, strut attachment doublers and tip spars bent up the other day. Due to the happy combination of a Saturday morning to myself and the kids both sleeping for 3 hours in the afternoon, I pilot-drilled the doublers & L stiffeners to the spars and cut the extrusion to shape for the front strut attachments.


After some solid riveting practice, I'm now ready to attempt riveting the spars together... nervously... (jeez I'd hate to bugger it up on the last rivet!!)



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Originally posted 13 November 2011


Commenced solid riveting on wing spars. Almost completed one spar - found it difficult to set the rivets along the top of the spar doubler because of the bend at the top, so have ordered a 5.5" head which should be long enough to prevent the spring on the air gun from hitting the bent section when setting.


Happy with most of the rivets - had a couple that I had to drill out and re-set because of damage to the head caused by the gun slipping, but 99% worked fine.


Also cut the front upper strut fittings (7V2-5) and tie-down rings (6W9-1) from 0.125".


Learned a lot about setting solid rivets - hopefully the other spar will be problem-free!



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Originally posted 22 November 2011


Wing parts fabrication.


Cut out the 8 flaperon brackets and 8 slat supports from 0.090". I don't have a bandsaw, but it's amazing what you can do with a table mounted circular saw, a belt sander and some patience...


Tried the new 5.5" solid rivet driver on the remaining spar rivets on the starboard spar. Found it tends to kick around more than the short heads, so even more care has to be taken.



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Originally posted 29 February 2012


PLEASE tell me the spars are the hardest (physical) component of this plane to create. After 286 solid AN5-6 rivets my left shoulder, neck and lower back are aching. I know there's a few more to go... some longer ones on the spar root fittings, a few in the cockpit, not to mention those pesky little 3-3 suckers on the trailing edge... but I'm over it. After this plane I never want to see a solid rivet again, let alone set one. I'd have a ceremonial "chucking the bucking bar" in the dam, if it weren't for the fact that after I did so I'd find one last solid rivet to set.


Anyway, whinging aside, the spars are done. They're even the same length, which hopefully means my plane won't fly in continuous circles.


I've been out of it for a couple of months so it feels good to get back into building. At the moment I'm waiting on an order from Zenith which includes the spar root fittings and a heap of fuel tank hardware, so I guess the exciting parts of the wing building are about to happen!




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Originally posted 6 October 2012


I was ashamed to see I hadn't done a build update since February 2012 - 18 months!!


Had actually done some building work in that time (not much, admittedly) - but have done the rear spars, clecoed the top skin on the right wing and flipped the wing over.


Today I got back into it after a few months of no activity, drilled the bottom skin and positioned it, and got a few clecoes in. Glad to break the seal again and hopefully will be doing more building in the evenings now that we have daylight savings, and the weather is getting a bit warmer!



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