krproton
Posts: 365
Joined: 8/5/2007
From: Champaign,
IL, USA
Status: offline
|
quote:
ORIGINAL: normandouellette
Tim, if you read this, is the B.25 tail heavy with the OS70's. By design it looks Tail heravy and rerading the instructions it is suggested to install the battery in the noze section below the noze gunner section. I presume that the aircraft is tail heavy.
Hi again normandouellette.
Sorry if I tend to turn a simple answer to a simple question into a longer one, but you asked me if the B-25 is tail-heavy. Well, I don't think a model can be considered tail or nose-heavy until it is finished and all components are installed and an inordinate amount of ballast is required to get it to balance at the specified C.G. That said, the instruction manual illustrates the Rx battery mounted under the nose-gunner cabin so that little or no additional ballast would be required, thus ending up with a model that is neither nose nor tail-heavy. Our show model--the one used for the instruction manual and featured in most of the advertising photography and the flying videos--looked like it was going to come out nose-heavy, so I mounted the Rx battery down inside the fuselage just ahead of the nose steering servo. But after the model was completely finished and when I was preparing it for flight, it ended up requiring nose weight, so I removed the battery and re mounted it up under the nose (where it is shown in the manual).
In my personal B-25 (built from production samples), I went ahead and mounted the Rx battery in the nose under the nose-gunner cabin (where shown in the manual). Upon checking the C.G. later, the model balanced perfectly--no additional ballast required in the nose or tail.
This isn't to say that all B-25s will balance the same--there must be an allowance for different wood densities, radio gear, etc., etc. In the manual we note that you could wait to install the battery during the C.G. procedure, then you can mount it where required to eliminate or minimize any additional ballast that may be required. Or, if you prefer to mount the battery earlier, just go ahead and mount it in the nose where shown. In most cases, little or no additional ballast would be required.
So, I guess the short answer to your question is, no, the B-25 is not tail-heavy. 
_____________________________
Tim Lampe
Hobbico R&D
|
Printable Version
All Forums >> RC Airplanes >> ARF or RTF >> RE: Top Flite B-25 ARF (Tecnical, tips, suggestions) 
RE: Top Flite B-25 ARF (Tecnical, tips, suggestions) - 
Powered by O.S. .70 Surpass IIs, this thing ROCKS!!! Full-throttle, low-altitude fly-bys will get your heart pumping--don't worry! And she flies most scale-like at about half to three-quarters throttle. Any two-stroke within the recommended size range will yield the same result or better. 
