Cone too big for engine?
02-21-2011, 02:09 PM
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Cone too big for engine?
Hi guys, I have a question specially for all giant warbird (engine) lovers.. My new project will be about 2.8m (110 inches) wingspan and will have a mvvs 152cc (or at least thats what I had planned..) I understand that should be more than enough for a 20-25 kg (44-55lbs) AUW. Now my problem is that the real bird was rather small and overpowered, as a result at my scale it comes in with a quite bigger cone than most warbirds have. Is that cone size and weight (maybe 1.6lb / 750 gr?) too much for the engine? I am also concerned about it having to be perfectly balanced or it will tear the engine into pieces.. (that should be anyway the case in all engines, but at this size even more..)
What'cha guys think? Thankssss
What'cha guys think? Thankssss
02-21-2011, 04:00 PM
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RE: Cone too big for engine?
Very important that the spinner backplane is perfectly drilled center and spinner balanced with no wobble. Tru-Turn will make a perfect spinner for this application. Costly, the best, but worth it!! Paul
02-21-2011, 07:37 PM
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RE: Cone too big for engine?
Big Spinner no problem. I have an 8.5 inch spinner, that weighs 2.25 pounds on my 118 inch P-40 on a 118CC single jug. It causes no issues. A stated above, I took great care in balancing the back plate to avoid wobble. I also have an 8.25 inch 2 pounder on my 3W120 installed on my 115 inch Polikarpov I-16. As long as it is a balanced assembly it will cause no issues. They do tend to act a bit gyroscopic, so be aware of delayed RPM spool up and spool down.
The P-40: http://rcwarbirds.com/Aircraft/Figth...ffsp40page.htm
Jeff
The P-40: http://rcwarbirds.com/Aircraft/Figth...ffsp40page.htm
Jeff
02-22-2011, 10:08 AM
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RE: Cone too big for engine?
Meschmidt, thanks for the tip, I checked Tru-Turn, it seems they do personalised projects but in between 700$-2500$, I am afraid mine would rather be on the higher end (if not more), I will have to check if I can build it myself first..
Prop Wash & Stuka Barry, if I told you I would have to take your life, sorry mates
You will see the project once finished (give me something like 50 yrs..) but anyone who knows me will know it will be a unique project.
F4u5, thanks for the confirmation. It seems it works on yours, mine would actually be almost 14 inches! Can't tell the weight yet though.. Thanks for the tip re gyroscopic effect, I didn¡t think about it but makes actually sense.
It would obviously be safer to go with a bigger engine but then it would be like cramming a 100cc into a 2m plane..
Does anyone know if custom made carbon spinners are made (not sure this would be cheaper or more expensive than alu, does not need that machinering but the material is obviously more expensive than alu..)
Thanks for your input guys
Prop Wash & Stuka Barry, if I told you I would have to take your life, sorry mates
You will see the project once finished (give me something like 50 yrs..) but anyone who knows me will know it will be a unique project.F4u5, thanks for the confirmation. It seems it works on yours, mine would actually be almost 14 inches! Can't tell the weight yet though.. Thanks for the tip re gyroscopic effect, I didn¡t think about it but makes actually sense.
It would obviously be safer to go with a bigger engine but then it would be like cramming a 100cc into a 2m plane..
Does anyone know if custom made carbon spinners are made (not sure this would be cheaper or more expensive than alu, does not need that machinering but the material is obviously more expensive than alu..)
Thanks for your input guys
OK Petronio,sounds great.Keep us posted.Tom
