Discussion in 'The light stuff area' started by MadRocketScientist, Jun 19, 2009.
No wiring guide with this one and that's just for one engine! It's not as bad as it looks:gig:
That's good! :gig:
Making progress on the test stand! Still a lot to do before I can fire this one up:cry: The exhausts need to be fabricated, the fuel tank installed and plumbed, wiring finished etc etc.... the engine mount needs to be made in aluminium.... you get the idea...onder:
I think the engines are going to be mounted flat, its far easier to fit the exhausts past the engine mount.
Started mocking up the two in to one exhausts for the tuned pipe. Its going to end up slightly offset to keep the pipe lengths the same. I may run the engine on straight pipes to start with :roll: That should annoy the neighbors!!!
hey Shannon . would you like to offer a kit?
I cannot offer kits as the plans are available elsewhere. But I can provide whatever parts you would need if that helps?
Well, I'm now the proud owner of a Class 1 microlight. I have no idea what it is and neither does the seller. Maybe someone here will recognise it. Rotax 447 and trailer alone are worth what I paid for it, so essentially I got the airframe free.
More progress, was it worth the long long wait for the build to continue? :gig:
Yesterday I machined the rear engine cover to reduce the clearance of the rotary valve. Reading the manuals for the jetski two strokes they run the clearance at 0.3mm +-0.05mm. They also state not to go under 0.25mm as the heat changes in the housing may cause the valve to bind and gall. Given that the ZDZ is a smaller engine I think the clearances could be used with no problems. I certainly think you don't want them any bigger! Symptoms of an excessive rotary valve clearance include rough idle and not so smooth throttle transitions.
I checked the clearance on the ZDZ by placing some small pieces of solder inside the housing and bolting it down. The clearance was quite excessive at 0.56mm. I set the rear cover up in the cnc and milled 0.26mm off it. Ignore the big "E" as I used a scrap of 30mm thick clear acrylic to mill the mounting spots to bolt the housing onto. Much easier to set things up level with a freshly machined surface. Then I used a dial gauge to check the level of the inner housing where the valve runs. That was level to within 0.02mm so then I machined the surface. I hit it even more precision than it was originally with three final clearance measurements around the outside being 0.30, 0.30 and 0.31 mm :ban:. Lapping the surface with some 1000 grit sandpaper took it down 0.02mm further but it will get a little thicker when it has the spray gasket applied for sealing on final assembly. I may not be able to tell if this has done anything to the performance but it good to know where the clearance is at.
Today I did some more on the test stand. I want to test out the actual engine mount design that will be used on the plane at the same time. The angle of steel will be bolted to the front of the plywood and the engine mounted onto the steel with the aluminium mount. I can flip the steel piece left or right to simulate the motor mounting on each side of the plane
Also attached are some pics of the comparison of cleaning up of the pistons, not sure how I missed posting them the other week??
Seems we have another good option from ZDZ for engines for the CriCri, The new ZDZ180 is around 19hp and its lighter and quite a lot cheaper than a ZDZ210.
ZDZ 180B2RV-J Rotary Valve Gasoline Engine with Electronic Auto Advance Ignition (ZDZ180B2RV-J) - troybuiltmodels.com
Shameless 'borrowing' of the picture from TBM
That's a cool little motor.
US$1395 for a t(r)oy engine, on special? Wau. I didn't pay much more for the aircraft above, with a low hours Rotax 447 and a trailer. Happy.:ban:
Found out what it is, the seller sent me a photo of the build plate. Homebuilt, type "Rainbow Chaser" S/N 001. Probably a prototype.
I have been working on mapping the ignition advance of the ignition modules I have here. Turns out that the Rcexl units I have are set at the advanced position and the software in them retards the firing when it senses fast enough rpm. The issue is when it takes around 400rpm for the retard to kick in. On a smaller motor, say 50cc, this isn't an issue as it is really easy to hand prop a small engine fast enough for it to not kick back. With a bigger engine like the ZDZ210, the kickback can be rather vicious if the timing is fully advanced when they are hand propped:mad2:. My units seem to be fully retarded around 110 rpm so may be fine!
The idea is to make sure the retard kicks in :gig: at a low enough rpm for it to be a non issue.
The Falcon ignition units that came with the motors have a bad track record as far as reliability is concerned although they are set at the retarded position and the software sorts out the advance. Helps a lot with kickback when hand propping .
Sure is interesting reading all about the effects of timing on two stroke engines.
And now one of the Falcon ignition units that came with the motor is flaking out, works fine when cold but once it runs for a few minutes it goes nuts and fires all over the place. Didnt even get to test the timing properly on this oneonder:, oh well back to testing the Rcexl unit.
Yep, some of the original ZDZ / Falcon ignitions are crappy (me too I had years ago a forced RC-landing with a 60 cc ZDZ because of ignition failure, moving then to MVVS 58cc - a bit more thirsty, but very reliable) - so, good move to Rcexl, Shannon! (well, I guess your engines are not so much... ZDZs :gig: after all your changes.)
But have you ever considered the (more expensive, complex and heavier) E-start sollution?
I'm anyway eager to see your conclusions after the first engine-tests on the bench!
P.S. That 180 cc RV ZDZ for 1K euros is also a great offer indeed (in Europe it's 1.549 euros) and I'm inclined to choose it for my microlight project, mainly because of its lightness (3.3 kg for +19 HP instead of 4.9 kg for the +22 HP of the bigger 210).
I have thought about starters, I just want to get these up and running before adding more complexity! I may need more weight up front to get the CriCri to balance. Starters and alternators will fix that.
I am interested to see how reliable the ZDZ180 turns out to be, every new ZDZ engine type seems to be that much better than the last. From pictures of parts of the 180 they have improved the design over the 210.
I have been working on a solid model over the last few days, still a bit of work to go till its right.
Just a bit of Mahogany
Just spotted the new Colomban design, the MC30 Luciole. Wow, now that's beautiful. Pity about the cost of his plans though.
Colomban MC-30 Luciole - Wikipedia, the free encyclopedia
I haven't posted any updates for a week or so but that doesn't mean nothing is happening:gig:
Ended up fixing a friends chainsaw and now it goes better than it ever did. A new carb kit and a few other tweaks and its going well, although it still had a crazy rich midrange that I would have liked to sort out...:ermm: The saw wasn't really worth repairing for the time it took but I learned a lot about two strokes by doing so.
I have finished the test prop for my ZDZ210, few pics below. Some lightweight glass cloth and epoxy should stiffen it up a bit and then I sprayed it with sanding sealer then a clear lacquer top coat.
The MC-30 is another great minimalist aircraft, from reading reviews it still seems to have the difficulty with the engine cost once it has be made airworthy.
Yeah. I contacted the UK Luciole group and evidently the engine upgrades are available only as a kit from Colomban, and very expensively at that.
On another tack, have you found a reliable supplier of aircraft grade aluminium in NZ or does it all have to be imported? Reason I ask is that I'd like to take a crack at building something eventually.
Separate names with a comma.