Karl: Have you tried a prop with more pitch than the 12"? Theoretically you should be able to spin a 32x20x2 at the same rpm which would provide a lot more speed, and possibly the inertia to perform bigger maneuvers, even though the static thrust would be a little less. A compromise prop could ...

The original Mk. IX has a power-to-weight of about 2 kg/hp. Your engine will crank out about 15 hp I guess which then matches a takeoff weight of 30 kg. With your projected weight of about 40 kg I would think that it would be very underpowered with the 124 cc twin. Detlef Kunkel in Germany have used...

I live in Denmark where we have a max weight limit of 25 kg ready to fly. :-)

What do you estimate the final weight to be? A friend of mine is on standby, waiting for my inline to reach a level where it runs reliably, and then he´s planning on building a 1:4 Spit Mk. XVI for a geared triple. That should make it possible to run a scale size 4-blade prop. And with a little plan...

Good job.

Looking forward to the video. :-)

What prop are you running on the engine now?
I´m considering making a tripple myself for a future project, and this will also most likely be geared.

Thanks for the reply. Seems I´m on track for a sweet flying 50. :-) The Moki 250 has been run on the test stand, using the proposed engine dome, and it runs perfectly it seems. Much like a full size engine it runs quite lumpy at low idle when cold, but after 20-30 seconds it smooths out and ticks aw...

What are your plans regarding the retracts? I assume that the basic construction is similar to the 50, just adding the extra cockpit, retracts and the flaps? One more question. I´m building a 1:3 scale 50 myself, and this is set up with the original Clark YH airfoil, set at +2° incidence. The engine...

I turned down the rear crankcases today. Not much runout, maybe 0,1 - 0,2mm, but everything counts. I´m hoping that the couplings will be ready tomorrow. They are made from extremely hardened material, much harder than a normal drill bit, so the holes for the set screws will me machined on appropria...

Further testing have been put on hold until I can make two modifications. After running the engine with the canister, and without hearing protection, I became aware of a loud metallic noise when the engine was running. Actually it´s louder than the echaust at idle!! I could also be felt when turning...

Yeah, if I had the possibility I would also make the frame more substantial, but as previously mentioned the max weight limit of 25 kg is getting dangerously close. I have soldered up a simple header to connect a DA-150 canister, so my hearing should not be damaged quite as much in the future.:-) Th...

I´m looking very much forward to hearing about your experiences regarding the Solo prop.
I can´t find you on FB to see the video, but I guess it´s very similar to my own engine, just not as loud. :-)

BTW, engine weight.

Engine, with drive and all needed bolts, standoffs etc.: 4812 g (10,58 lb)
Ignitions: 224 g (0,49 lb)
Total ready to run weight: 5036 g (11,07 lb)

When it´s fitted with exhaust system my guess is, that the weight is about the same as a Moki 250. Not too bad.

Sounds good Dave. I did a little more testing with the engine today. For some reason it will drop the front cylinder once in a while, especially at idle, where it only fires every two or three revolutions. If I can get the engine to accelerate it normally clears up but it will also drop the front cy...

Hi Dave If you look closely you will notice that I have located the additional pickup on the Torquemaster frame. That way it´s located 180° across from the original. I initially intended to run a flywheel on the rear crankshaft and mount the pickups there, but since the flywheel fits on the tapered ...

So, what hopefully will be the final version of the engine is now finished, and ready for a test run. After going through several different versions of mounting systems this is by far the best and most rigid. Previously the two engines could be twisted slightly which is not the case any more. The fi...

Can´t have too much Clutch.... Best live band I have ever seen by the way. :-) On the serious side though. For cutting and drilling plywood I use, well - before getting the CNC mill that is, a bandsaw to cut out the parts and a disc sander to get them to spec. Then it´s possible to make very accurat...

Cutting ply? Use one of these fellas!

Sorry, couldn´t resist. :-)

So, a little more progress today. The engines are now connected with the new mount and all that´s missing is a bracket of some sort to hold the pick-up´s on the rear flywheel. Then I should be ready to start it up for testing. The mounting seems nice and stable, but I cannot conclude anything until ...

Looks promising David. What kind of hub are installed on the inline? I have considered buying an adjustable hub from http://www.sl-propeller.de/. If my cnc mill can make the blade hubs with enough precision I will be able to make my own scale props in the future. And when running a reduction drive i...

Looking forward to this, as I´m eventually going for a tripple myself one day. And even though I normally prefer the sound of a gas engine running at very low rpm, 4500-5000 in the case of my King 140, I can also appriciate the aggressive sound of a two-stroke tripple inline. Nothing comes close to ...