Hi guys I guess the only thing that needs to be remembered is the prop tip must never become supersonic so work out the prop dia and what rpm keeps it near supersonic and that will be close to the prop rpm.
Cheers Innis
From: Arnt Karlsen <[EMAIL PROTECTED]>
Reply-To: FlightGear developers discussions <flightgear-devel@flightgear.org>
To: FlightGear developers discussions <flightgear-devel@flightgear.org>
Subject: Re: [Flightgear-devel] Help with B-29
Date: Sat, 19 Mar 2005 06:24:26 +0100
On Fri, 18 Mar 2005 11:14:45 -0800, Andy wrote in message <[EMAIL PROTECTED]>:
> Josh Babcock wrote: > > OK, here's the file: > > http://home.comcast.net/~jrbabcock/superfort/b29-yasim.xml > > Some random notes, before I start running it: > > The inbord and outboard engines don't match. Your inbord ones are > defined to produce 2200 HP at 1000 RPM (which is *monster* engine), > while your outboard ones get 2200 at 2900 RPM (a little over 1/3 the > power of the others). The inboard ones look typoed to me. > > I see that all your propellers have a gear-ratio="0.35" setting. This > is almost certainly wrong. The B-29 used big cylinder radials, and as > far as I know no one ever made one of these with with a gearing system
..no? Those late and post WWII big ass corncobs were all geared, to stay as small as possible. ;o)
> (no point, as pistons that size can't be made to move much faster). > Note also that this doesn't match your (outboard) engine settings. > You have a propeller that wants to sink 1800 HP at 2200 RPM. But at > that speed the engine would be turning at a shaft-melting 6285 RPM. > > The props also have buggy settings for their controller levers. The > are "power-calibrated" at 2200 RPM, which matches the engine settings > you have. But the max-rpm value is only 1200, so the governor will > never allow them to turn that fast.
..those B-29 props was spun at 910 rpm by 2200 T/O and military ponies spinning the crank shaft at 2600 rpm.
http://www.wpafb.af.mil/museum/research/bombers/b3-30.htm http://www.google.com/search?num=100&q=B-29+R-3350+rpm+%22gear+ratio%22&ie=UTF-8&oe=UTF-8
> I'll try these changes as soon as I get a chance and see what happens. > > Andy > > > _______________________________________________ > Flightgear-devel mailing list > Flightgear-devel@flightgear.org > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > 2f585eeea02e2c79d7b1d8c4963bae2d >
-- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case.
_______________________________________________ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
_______________________________________________ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
