All fueled up and ready to go. Probably have to wait until monday for the initial test run, this weekend is packed with appointments and kids…
Servo compartment detail. The Hitec really impress with their speed and strenght.
The tank is a Tettra 560cc crank tank. Gotta love that name, and it’s a really sweet piece of kit. nothing I’ve used before comes close to this quality.
It’s amazing what can happen in 30 minutes in the workshop. Suddenly several evenings worth of fitting, adjusting, drilling, grinding, fitting, throwing away, grinding more and even gnashing of teeth came together on one go. Once you decide that a good fit is good enough, go for it. And the damned thing fit like a glove. This was just a dry-run, gluing and fuelproofing comes later. And when that’s done, I don’t know what’s left. Fly maybe?
Here’s the tail linkages. Done with that too. There’s a good lad.
I have finished installing a Perry pump in the standard (unpumped) O.S 200 FS that will power my new Laser F3A model. As you can see the pump is hung on to the engine mount, adding minimal weight and is a compact installation that I’m very happy with.
The fuel line that pressure feed the pump is routed through the engine mount, as straight and short route as possible. The tap is a 4mm pressure tap. Tapping the crankcase is tricky- there is no clearing on the inside and the cast backplate is VERY thin. I did my best so I hope it’ll hold. The crankcase is in fact already tapped on this engine. Not visible, but just above my pressure tap is a cast hole that has a pressure feed going into the carburettor. No Idea why, but I hope there’s enough pressure left for the pump…
The whole assembly including pipe. The Hatori header requires some work to fit this engine. The exhaust port is deeper than on the 200 EFI so I needed to cut a big spacer from a plumbers copper joint in order to be able to tighten the header nut. I also had to drill and tap the top to accept the screw from the header fastener. Presumeable this fastener is to prevent the header from cracking from soft-mount vibration.
Here’s the updated plumbing on the 160 with the Perry pump installed. Pretty straightforward, so with hindsight I guess there was nothing to worry about but I’m also glad I’ve got experience of running it without a pump. Since the picture was taken I have added a Sullivan Crap-trap fuel filter between the tank and the pump. I replaced some fuel lines and made them more accessible, plugged the pressure tap in the pipe and routed the vent line to come out of the belly just behind the cowl. The tank has been repositioned on a new tank tray and the throttle servo moved forward for a straighter linkage.
It all worked very well, the engine ran happily at 7800 RPM with more to go on an APC 18×10 PN prop and idling at 2000 RPM (1500 possible but shaking a lot!). Initially I was not able to figure out the idle, I didn’t count on having to turn the low-speed needle a full two turns in, but that did the trick, the pump really does deliver great amounts of fuel and both needles required considerable adjustment to run with the new setup. So now all I have to do is fly.
Interestingly I had a bad case of hysteresis with the throttle setup. Idling at 1500 or so RPM, I ran it at full throttle and then it returned to 2500 when the throttle was retarded, giving a difference of 1000 RPM. I guess it’s a risk we take with soft-mounted engines. I have a digital servo on the throttle but that does not help – the servo will hold but the engine shakes in the other end, pulling the linkage and increasing the carb opening. I’ve even had a case of a plastic link jumping off an idling engine, it came to full power and there was nothing I could do to stop it. The plane roared into a fence, breaking a wing and barely missing my leg. Since then I respectfully and carefully install linkages in my models. But hysteresis is a big problem. I’d love to hear from readers who have experience (and perhaps solutions?) with this. Leave a comment and we can have a discussion.
What am I doing? Lots!
- Repairing the Saphir II: New Tru-Turn spinner, new prop (APC 13×10 turning 9800 rpm), new covering on the wing (AGAIN!). And taping and sealing off every damned piece of covering I can, a piece flies off every time it flies.
- Repairing the red Laser, fitting new wheels (lost one in flight) and fixing a crack in the undercarriage, new bolts, fitting a Perry pump (damned 3,5 mm tap-stuff!) , moving the tank and moving and fitting a new throttle servo.
- Blue Laser – Fitting a perry pump on the OS 200 FS, attempting to fit a Hatori pipe in the nose (Damn that nose)
- Building a new fieldbox with space for 18 inch props. Pictures coming soon
- Buying stuff – a Proxxon table saw, Graupner fieldbox (I must have two dammit) and a Schulze Lipo Card (nice to carry in one of the new fieldboxes)
In addition to that my two kids are not in kindergarten this week so I have my hands full from 6 in the morning to 8 in the evening. And we’re tidying up the house, cleaning out the attic, moving the lawn, painting the damned pipe and every other task that can fit into my cramped short-term memory. And tomorrow evening I’m going flying the Saphir. Gotta love flying!
PS- notice the kid behind the plane?
I flew yesterday! There’s hope after all…
The red Laser performed well during two test flights and the engine was well behaved. New fuel was probably a good Idea.
I also test flew the new Kyosho Edge. All went well, I had just enough time to think “wow, it’s rock solid and needs no trim whatsoever” and then the plane started leaning to the left, and then some more, and when I reached for the trim lever – BAM – no control. After a series of flick rolls I regained control and managed to land safely.
It scared the shit out of me but that serves me right. I used a parkflyer type receiver (Corona) that is not meant for this type of plane. And I didn’t range check before I flew. So there. But I’ll try and learn from it, be happy that the plane flies well and is whole, and spend some moooneys on a new receiver as soon as possible.
The standard Lorenz soft mount was used. It’s just four rubbers attached to a glass/epoxy plate plus a fibre-filled glass mount.
