A local modelor has just finished drawing up a fine set of plans for the RQ-1A Predator in Autocad to 1/8 scale. Thats about a 72 inch span. The structure is a combination of built up balsa, foam wings and a fiberglass forward fuse.
He plans to build a gas powered one for himself and I am trying to convince him to have a few sets of plans printed. They can be printed full size on a plotter.
Is there anyone interested in building one? Help with selecting a power system and weight control would be greatly appreciated.
Here is the specs for the full size one:
Payload 450 lb
Wing span 48.7 ft
Span Sea Predator Variant 35 ft
Length 27 ft
Performance
Altitude 25,000 ft
Range 400 nautical miles
Cruise Speed >70 kts
Endurance >40 hrs
Weight fully loaded <2300 lbs (1035 kg)
Weight payload 450 lbs (202.5 kg)
Electro-optical payloads
2 colour DLTV television variable zoom, 955 mm Spotter
High resolution FLIR 6 field of view, 19 to 560 mm
Synthetic Aperture Radar all weather surveillance, 1 foot resolution
Optional payloads laser target designator and rangefinder, ECM/ESM, moving target indicator, communications relay

What would you charge for a set of plans at 1/16 scale, or
36 inch span? The Predator is on my backlog to build in electric,
but might be a couple or three years away....
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James

I would be interested, but not at 72"!

If he would send the DWG I could plot it on my e-size inkjet at an appropriate size for electric. My personal choice would be about 30" span and I would go for a simplified construction rather than a perfect scale plane.

Have him e-mail me montana@fast.net

Andy

Make sure he designs it to haul around a camera 36" sounds like a good size. What would the wing loading be at that size? Those wings look kinda tiny; this might be a little rocket, unless it comes out real light, would take a lot of power and fly like a bat outa hell...

1/8 70 knots scale speed is about 10mph, btw. 1/16 would be 5mph. This would make a killer park flyer

Please, oh please make the DWG file available, so we can do it in whatever size we want!!

Please??

I agree with the others. 1/16th scale would be perfect. I drive a Saturn, and can only load a 62" wing in it .

The wing aspect ratio is longest....

I'm interested in building the 1/8 scale version. That gives a fuse at 40.5 inches which shoud be able to haul around some video downlink gear. I need help with the wing core and the fiber glass.
Are you planning retracts?

--Carl

Scaling off that image, wing area looks to be (appx) 117 square feet. (It's hard to pin down, as the dimensions shown don't match the scale.) So, 1/8 ( 73") would have 1.8 square feet area, and 1/16 (36") would have 0.45. You can do that math, but seems to me that, unfortunately, a 36" version probably won't fly too well...

The Predator is pretty much a powered glider, hence the aspect ratio. It seems that a 36" wingspan would be way too small (HLG territory!). The 72" span may be about right for this one. Its not supposed to be a turn and burn speed demon.

My e-photo planes use 2-meter wings. With the lightest film camera I can find, the Canon ELPH-LT
8x1400 and a 3:1 gear box give adequate performance.
Predator's rear mounted motor will be a problem.
The nose gets VERY long to compensate.
I put the surfaces on top to cut the amount of landing damage, also...
http://www.angelfire.com/indie/aeros...hotoPlane1.htm

Has anyone used driveshafts to power an electric model? A nice lightweight carbon shaft would allow the motor to be mounted just about anywhere

Originally posted by Steve Fehr
1/8 70 knots scale speed is about 10mph, btw. 1/16 would be 5mph. This would make a killer park flyer

That's not the way the scale speed calculator works.

It has been explained to me that you use:

speed = (square root of the scale factor) x actual

So for a 100 mph plane at 1/8 scale it would be

speed = 100 MPH x SQRT(1/8)
= 35 MPH

Which seems far more realistic.

Of course Mr. Reynolds steps in, too, and that changes everything!

Does anybody know what it is really supposed to be if the above is incorrect?

Andy

Originally posted by AndyKunz


That's not the way the scale speed calculator works.
Andy

Aerodynamically, you're correct, but that's not what I meant. When I think of "scale speed", I think of how it looks to the observer- 1/8 scale means you'd have to be going 1/8 as fast to look as if you're travelling the same speed. An HO train (1:87 IIRC) travelling 1mph in your house will look like it's going 87mph through a scale landscape. That's what I consider "scale" speed... A lot easier to do in trains than planes, I know

So far we a 1/8 scale plane with the motor mounted amidship with a drive shaft to the at pusher prop.

The next question seems to be what airfoil should be used at root root and tip.

I do remember seeing a version with the tail inverted, that is in a more standard v-tail with the same short sub fin. Both flying surfaces. I think that would make more sense for ROG.

Keep thinking.