[NSRCA-discussion] First day out with OS 140RX (somewhat long)

[Rcmaster199 at aol.com]

David, with judicious use of good material one can hack an ARFie model  to 
less than 10lbs. I did it with my Temptress (Temptation very heavy composite  
fuse and own feathers, own gear design, etc). The span isn't full 2 meters (76") 
 but it's close. The 530sqin wing panels are 15 ozs each all paint, which is 
too  heavy I feel. Lighter is doable with better technique. If I wanted to use 
 lightweight transparent film I could have saved maybe 1/2 oz each panel.
 
Starting with a clean slate, I believe a craftsman can build a full blown  
pattern model at around 9 lbs RTF, for fuel power. Possibly lower. That's  about 
what i shoot for for wet and 9.5 for present state electric power. I  am 
working on an idea to make 530sq in plug in wing panels RTF at about 10 ozs  all 
paint. Think its possible and stay together for the long haul. Trick is to  
make these techniques user friendly enough that anyone with average building  
skill can do it.
 
There are many places to save weight in any model, one of the easiest being  
the heavy ply reinforcing around the landing gear box. I don't believe a box 
and  block is necessary. Load distribution is the key and that's doable in 
other  ways.
 
Another place is to toss that composite stab in the garbage and build one  at 
the right weight. Composite rudder also. That's often crap. Of course if one  
doesn't know how to make these parts from scratch at the right weight, then  
thats no bargain either. And if the ARFie is heavy elsewhere to compensate, 
well  that's really no bargain.
 
I look at it this way. Our CL Stunt cousins build 60 sized models that  weigh 
in 50-55 ozs with about 700 sq in of wing, and it's all paint. These guys  
are real masters at the craft. I am learning from them and I urge anyone who is  
keen on building and finishing technique to take a much closer look. Ohh, I  
forgot, they still have the builder of the model rule in place.
 
regards,
Matt
 
In a message dated 3/3/2006 12:49:49 PM Eastern Standard Time,  
dflynt at verizon.net writes:

On a  separate topic, you can build a very light plane if you select  light
components such as PBG wing and stab tubes, carbon fiber mufflers,  etc.
Most guys overlook the weight of covering and paint.  Opaque  monocote and
ultracote are pretty heavy.  I have not been able to  cover a set of wings
with monocote using less than 4 ounces.  If you  want to half that, then I
recommend a lightweight transparent film I used  Ultracote lite.  It is very
light, sticks well, and is as easy or  easier than monocote to work with.  I
have no wrinkles on my covering  (yet anyway -- I'll have to wait until I go
to Vegas and Phoenix to see if  that holds up), and it looks pretty.  For
paint, you can cover a big  2m plane with three ounces.  Sometimes less.
Craig Blodgett told me  that he used just one ounce on his Smaragd!!  In my
opinion and  experience, all of the 2m planes that we fly can be built less
than 10  pounds with the glow engines we use, and they will hold up well  too.


I would like to see somebody paint a set of wings using just 2  ounce of
total material, then I will start painting wings.  Anybody  (Matt?) have a
formula for that?

David


 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20060303/f94298db/attachment-0001.html