Hello,i need to say im living in the middle of the european Alps in a skiing place on 6000 ft.There is a very nice meadow 1100ft long and 15 degrees banking.this is the place where i want to takeoff and landing.So yesterday i made static engine tests with my prop. this is a 54x24 one but compared to others here, have larger blades.the specs are 94x86, std cam, CR of 8,15:1, two 26mm Keihin copies carbs, setup lightly rich.i was a little disappointed because turns only 2750 rpm and 125lb of thrust. Air temp was 59 F and EGT was 1100 F.i mounted a fliter oil pump with 29mm large gears and was wondering of the high pressure too: it was over 6,5 bar in idle and the same with full throttle, oil temp was 95 F.Please someone can help me with my numbers ? Are they normal?The pic is my prop.Hermann
RE: user prop experience:Hermann,I've tried a number of props out of 1450 & 2600 ft ASL strips on a 35 hp 1/2 engine - the LE 10% overgross... The 54 x 24 is too much prop... The best performer was a narrow tip 54 x 22 cut down to a 52 x 22...Leonard has had a number of props on the prototype and liked his cut down 52 x 22 prop best too... The 45 hp engine is a different animal and Frank at Performance Propellers has done a lot of prop development on that engine... Les Homan has flown the Performance Props to high altitude (above 7k)... Those are the guys to talk with... On a 54 x 20 prop my 35 hp engine pulled 190 ft/lbs at sea level (I was showing 1400 F EGT!)... You need at least 140 ft/lbs of thrust on a LE at sea level to get a ROC between 100 & 200 ft/min at gross...Your interesting posts are appreciated!...Steve
an Thank you Scott for your infos.In the last 5 monts i read a lot of many different people and sites on the net and somwhere i found something of a guy they test a lot...maybe was you ? and than i have a request to all they have a shape for props: maybe someone have it as cad file or better, if someone can convert it to stl file, so i can cnc machine it on my selfmade hobby router. I think in certain limits its enough to scale the prop for different sizes. and:The working area is not that big enough to cnc the whole prop at one but if i drill first the center hole and fix a pin on the router, i can machine first one side and than rotating the piece 180 degrees make the other side. So i can make a prop up to 67 inch.EDIT: Sorry guys, found right now the topic with the numbers for the 1/2 VW engine....is big and fat at he top of this site.There is written on full case is very hard to reach 160 F Oil temp, and probably at my home is harder because the average air temps are lot colder than in Texas Is that a Prob if oil reach only something around 140 F ? I know that the ideal oil temps are around 165 to 195 F ...Hermann
