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Old Nov 17, 2014, 03:21 AM
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United States, TX, Lipan
Joined Jul 2013
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Troy Built Models UAV's

Looking for RTH (return to home) and gyro units Troy Built Models popped up in my search results. It was hard not to notice the UAV's in stock especially since several were big $$$$. What really caught my attention is the engine size, in fact I double checked it.
UAV Penguin B
MTOW 47.4 lbs 21.5 kg
Empty Weight (excl. fuel and payload) 22.05 lbs 10 kg
Wing Span 10.83 ft 3.3 m
Length 7.45 ft 2.27 m
Powerplant 2.5 hp
Max Payload 22.05 lbs 10 kg

My calculator says the power to weight ratio is 19:1 which seems on the low side of low. Of course the UAV is blasted into the air with a compressed air launcher i.e. like a V1 buzz bomb . No ROG rise of ground take-offs are shown either. Since many of you have practical experience in this area, it appears with this pwr/weight a paved runway and rather long TO roll would be needed to get airborne?

Am I missing something here? I have always considered 10:1 normal and 15:1 a stretch for aircraft small or large to operate in. In fact I doubt at 19:1 this UAV could take-off on an unimproved grass field. Additionally, given a wind of >10 mph could this UAV make any headway rather just hover especially considering the frontal area.

I would appreciate your thoughts especially since other UAV's aren't as aerodynamic still use this same engine.

Regards Ed
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Old Nov 17, 2014, 11:25 AM
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Hegra, Norway
Joined Feb 2007
145 Posts
The Penguin B exists in relatively large numbers, so I guess it must be doing something right. We have one at my job, but I don't get to fly it. A grass take off would be challenging, but in the air it's ok.
Manufacturers homepage:http://www.uavfactory.com/

Lars
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Old Nov 17, 2014, 04:22 PM
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Palo Alto, California, United States
Joined Jan 2003
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My company sells a similar aircraft (MLB Super Bat) and we regularly fly at 47lb GTOW, but we use a modified DA-50 for power. We dyno tested this engine at 4.0 HP. I don't think 2.5 HP at 47 lb is good enough for the work we do, but many people operate their planes heavily loaded without much climb margin.

Steve
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Old Nov 20, 2014, 03:31 PM
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Washington
Joined Aug 2009
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There was a good write-up on the Penguin B in the first issue of Unmanned Systems Technology magazine. Apparently, they have only made 100 -- which is a smaller number than I assumed.

I think it is optimized in the 35-40 knot range so a 10mph wind wouldn't be an issue. Keep in mind smaller electric systems such as the AV Puma are rated in winds up to 25kts.

If the lift to drag ratio of PB is ~20:1 like Aerosonde, then they don't need much power at all to maintain altitude. Yes, takeoff roll and climb rate will suffer from basic physics, but most missions wouldn't require this .. and you could always takeoff light if you wanted more climb, or better altitude performance.
Endurance is always a want for these birds so that's what drives the low power to weight ratios.
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Old Nov 22, 2014, 01:26 PM
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United States, IL, Edwardsville
Joined Dec 2011
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Is the math adding up on that tbm spec on the penguin b? The fuel burn is off? Am I missing sonething? Fabulous looking airframe!
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Old Nov 26, 2014, 11:43 PM
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Nottingham Road South Africa/Bedford UK
Joined Feb 2007
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I think its heavy fuel. They have made a 50 hour flight with it http://www.suasnews.com/2012/07/1740...ory-penguin-b/
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Old Nov 28, 2014, 11:22 PM
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United States, TX, Lipan
Joined Jul 2013
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I started this thread hoping to get some personal experience on powering personal UAV's. Especially dealing with wind penetration during landing is a concern even worse with a crosswind. Our little planes fly in full size air which frequently changes so about the only option is having enough power to maintain positive control, or am over compensating? Even worse the RC pilot has no physical sensation with the plane so he/she is always in the reaction mode often at large distances. So it only makes sense to have enough power to cope with these situations.

As a UAV pilot do you rely on gyro to deal with these situations again when your UAV is far from you? Do you run your powerplant at maximum or near so to keep positive control? Does power to weight determine your selection, or what value?

Your replies are appreciated, Ed
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Old Nov 29, 2014, 01:02 AM
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United States, IL, Edwardsville
Joined Dec 2011
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It sounds like your concern is related to stability and control and not necessarily power. The airplanes should all be inherently aerodynamically stable. To call the plane a uav, I think that suggests mission or at least a greater level of autonomy than an FPV or RC plane. This would suggest some kind of autopilot or stabilizer but it is not required.

The lack of physical sensation is a non issue.

The min control airspeed for nearly all airplanes is far less than the airspeed that can be attained at maximum power.

All airplanes have crosswind limits. They are not necessarily related to the power available.
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Old Dec 01, 2014, 03:38 PM
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Quote:
Originally Posted by Gary Mortimer View Post
I think its heavy fuel. They have made a 50 hour flight with it http://www.suasnews.com/2012/07/1740...ory-penguin-b/
It was a gasser 3w-28i
http://www.currawongeng.com/news.php
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