os 90 df speedplane
05-17-2007, 11:12 AM
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RE: os 90 df speedplane
Well, you've got the power... so it should move along nicely.
But I doubt you're going to see 300 from what looks basically like a Novice on steroids.
It is as good a place to start as any though... it should give you a nice platform to explore the characteritics of the OS 91.
Get rid of the APC prop! Too dangerous!
But I doubt you're going to see 300 from what looks basically like a Novice on steroids.
It is as good a place to start as any though... it should give you a nice platform to explore the characteritics of the OS 91.
Get rid of the APC prop! Too dangerous!
05-17-2007, 12:06 PM
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RE: os 90 df speedplane
what prop should i use i have not seen any thing other then apc and have been flying that prop a lot whit out problems... i knov its not ideal so any help is welcome.. still hopeing fore 300 
05-17-2007, 03:12 PM
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RE: os 90 df speedplane
A very smart design indeed. It should go very fast but as been said the apc:s are not strong enough for 15cc DF engines. A carbon fiber prop is the best choice or a strong wooden prop is also better than apc:s. Avoid chicken stick on all these props, a starter is much safer.
05-17-2007, 04:24 PM
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RE: os 90 df speedplane
R-C-Guy used that engine on a mustang with gear a few months ago and got a verified 180+ mph. Using a pitot tube and gps he convinced most of us it did happen. The thread is about 15 pages back if you want more info on what he did.
http://www.rcuniverse.com/forum/m_4898601/tm.htm
It would seem to me that 300 is in reach, especially if you could clean up the nose a little.
http://www.rcuniverse.com/forum/m_4898601/tm.htm
It would seem to me that 300 is in reach, especially if you could clean up the nose a little.
05-18-2007, 07:05 AM
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RE: os 90 df speedplane
yes mini pipe from weston uk .. works wonderfull 20000+ rpm on a 10x7 apc at with out to mutch noise.. where can i get these carbon props please help ... and it is going to get a nosejob i just want to fly it first...[>:]
05-18-2007, 10:02 AM
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RE: os 90 df speedplane
most of the speed freaks in Germany make their own carbon fiber props, it would be very hard to find commercially available CF props in the diameter and pitch that is used in the speed trials ..most use something in the vicinity of a 9 x 10
a brief overview of the process is to make a mold from an apc then use continous fiber strand and epoxy, cured under vacuum ( a very simplied explanation, but not overly technical either)
although that will be a fast ship as it is..like the others have mentioned that really needs to be fully cowled for serious speed, that engine is sitting high and would have considerable drag
a brief overview of the process is to make a mold from an apc then use continous fiber strand and epoxy, cured under vacuum ( a very simplied explanation, but not overly technical either)
although that will be a fast ship as it is..like the others have mentioned that really needs to be fully cowled for serious speed, that engine is sitting high and would have considerable drag
05-20-2007, 03:59 AM
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RE: os 90 df speedplane
i have not been able to find a sutiable prop anywhere so is it possible to take a larger prop and cut it down i diametre to get a stronger prop or is it a waste of time .... what are you other guys running on your engines??
05-20-2007, 04:05 AM
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RE: os 90 df speedplane
what is the problem with the apc prop they rate it at 19000 rpm fore a 10 inch so 25000 is just a small increese
Ed S
05-20-2007, 08:12 AM
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RE: os 90 df speedplane
i do understand the problem ... i just dont understand that it is inpossible to get a prop that works!!
(what is the problem with the apc prop they rate it at 19000 rpm fore a 10 inch so 25000 is just a small increese) joke!!!!!
(what is the problem with the apc prop they rate it at 19000 rpm fore a 10 inch so 25000 is just a small increese) joke!!!!!
05-20-2007, 09:45 AM
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RE: os 90 df speedplane
Well, it's not really a joking matter... if you always fly alone, and thus only risk hurting yourself and are prepared to take that risk, then go for it. Just remember that when one of them blades decides to part, it will do so at several hundred miles per hour...
These extreme setups are not a real big commercial succes, so no prop manufacturer is going to start making props that he can only sell a few of. There's your problem. That being said, Stuart at Supercool will make you basically anything you want... as long a you pay him
You could try contacting the German guys (there's plenty of extreme speed reading on the german forums), but I don't think their props are really suited for your plane. These guys are flying hugely "oversquare" props on very slick planes.
If you are willing to put in the time, it is perfectly possible to cut a very good wood prop by hand... but be prepared for a lot of trial and error!
Modifying a bigger prop is also an option, but you should source a carbon base prop just the same. The trial and error thing also applies here.
These extreme setups are not a real big commercial succes, so no prop manufacturer is going to start making props that he can only sell a few of. There's your problem. That being said, Stuart at Supercool will make you basically anything you want... as long a you pay him
You could try contacting the German guys (there's plenty of extreme speed reading on the german forums), but I don't think their props are really suited for your plane. These guys are flying hugely "oversquare" props on very slick planes.
If you are willing to put in the time, it is perfectly possible to cut a very good wood prop by hand... but be prepared for a lot of trial and error!
Modifying a bigger prop is also an option, but you should source a carbon base prop just the same. The trial and error thing also applies here.
