Recent content by Niels Abildgaard

I forgot where the big numbers are.Paragliding

20kW engines on MC30 Luciole

The distance between cam-/balance shafts can be around 280mm in my latest version. One revolving unbalance shall therefore give a centrifugal force of 50/0.28 or ca 180 Newton when doing 60 rps. If my calculationd are correct that is a point mass of 42 gram or 6ccm steel circling 30mm from shaft...

Now comes where expert help is needed. The mean torque is what turns the propeller and is arond 53Nm The reaction torque will vary from ca minus 50 to ca plus 250 Nm. This can be split in mean (zero order but useful for us) ,first order sine wave second order etc that make us miserable and...

20kW at 60 rps at a mean piston speed of 12 m per second can be schemed as a two cylinder two-stroke exhaust valved engine with cylinder bores of 66mm and strokes of 100mm. USA made more than 76000 mcculloch o-100 four cylinder two strokes that ran with a BMEP of 6 bar and mass per litre ca...

Have been reading around and will like to change dimension of goal. There is company working on postal UAVs and they use two 27horsepower/60 rps industrial V twins for propulsion. Flying Postman Same engine/ power (Serie 38 from B&S) are used by quite some homebuilt aircrafts named MC30...

Better fuel economy and less noise. Maybe

What Seagull model can be had today for what price? I am dreaming of making a side-exhaust-valved two stroke. If the nessecary cam sits just over the seal for crankshaft it will swim in oil.

To achive the non plus ultra we introduce a counterrotating balance shaft. For calculating and understanding we put centerline of balanceshaft coincident with crank centerline We have now 7.4 kg and COGMP do not move sideways and is mowing up and down ca 2 mm two times each revolution. This...

Having looked at the programe from dragonfly I prefer (surprice,surprice) to do it my way. Efficiency of crankcase pumping for two strokes is debatable matter. .If we ad some countermass to crank we can have less up and down but get some sideways and have ,of course, more mass. Sideway movement...

Using crankcase as scavenge pump the good old way. A scavenge expert said that due to undersquareness and uniflow,, brake mean pressure can be 8.5 bar or ca 68 horsepower at 3000 rpm. I need 40 horsepower at 40 rps and therefore ask for a BMEP of ca 6.25. A present family car with variable...

I have designed piston,rings,pin,conrod and buisness parts of crank to the best of my knowledge for lowest possible mass. First step is to remove so much material from crank countermass that comon center of gravity always stays on cylinder centerline. The mass of mowing parts is 5,86kg that is...

I spend time dreaming up best possible single person aircraft 30kW/40 hp engine, Be for ultraligth,paraplane or experimental. Slim people can fly in normal looking aircrafts on ca 30 horsepower if wings are long and/or structure very ligth. 40 horsepower is better and hangar hire less. One...

It is unforgiveable not to minimize mass of piston and conrod for single cylinder engines. CAD system calculates mass and center of gravity very precisely. Crank is develloped to minimum mass on the buisness side and then put all the contra mass on as possible. Ballance shaft as basicly a...

I want a new toy. Swan 120 SW Expensive toy I am not keen on engine that is a hard pressed single cylinder Pollini 303 (38 hp/8000rpm) with a reduction gearing turning a 1.5m prop ca 42 rps. Can of course make something better but will have to make a model to show all the doubting,wise guys...