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Old 02-06-2012, 05:46 PM   #1
cyclops2
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Default Minimum Flying speeds ? GWS Transport.

What was / is / the reliable minimum flying speed of the GWS 4 engined transporter ? Using 4 engines.

What throws on R, E, A ?
COG range ?
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Old 02-06-2012, 07:48 PM   #2
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Originally Posted by cyclops2 View Post
What was / is / the reliable minimum flying speed of the GWS 4 engined transporter ? Using 4 engines.
If you know the weight and wing area and it can be worked out, near enough.

V = √( 2 W g / ρ S Clmax )
where:
V =
Stallspeed M/s
ρ (rho) = air density KG/M^3 (about 1.2 kg/m3)

g = 9.81 m s^-2
S = wing area M^2
Cl_max = Max Coefficient of Lift
W = mass KG


Or, a simplified approximate calculation in ‘old units’ =
stallspeed = 5.25 * √wing loading

speed
in mph
wing loading in oz/sqft



Steve
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Old 02-06-2012, 08:15 PM   #3
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Default

Originally Posted by JetPlaneFlyer View Post
Or, a simplified approximate calculation in ‘old units’ =
stallspeed = 5.25 * √wing loading

speed
in mph
wing loading in oz/sqft



Steve
Hey, that's useful info! Don't need 1% accuracy, just whether its 20 MPH or 30 MPH

DennyV
Retired and the days are just too short, busier than ever!
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Old 02-10-2012, 01:45 AM   #4
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Get it up pretty high, reduce throttle and add elevator. When the ailerons begin to lose effectiveness you are about as slow as you want to go. A little more elevator and you will have an opportunity to also evaluate the stall and stall recovery characteristics of your plane.
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Old 02-10-2012, 02:45 PM   #5
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I'm guesssing that you are thinking of buy one. The GWS C130 is a very gentle flier. It hand launches very easily at full throttle and level to slightly down toss. Toss it like you are trying to toss a tennis ball about 15 feet.

It can fly very slow, almost like a Slow Stick meaning close to a slow jog speed, but without the sudden up/down of the Slow Stick. During stalls, mine just drops its nose gently. It will loop and roll....but certainly does not look anything like scale doing that

Built mine completely stock and by the book. It WILL NOT take off from even very short grass, but a paved driveway is perfect. If I was building mine over though, I'd leave the landing gear off and just keep hand launching it.

I used the throws in the book and they were spot on for good handling.
elevator - up/down 12mm
ailerons - up/down 10mm
rudder - left/right 20mm

My CG was at 50mm from the leading edge at the wing root.

The only difficult part of the building was the mounting of the prop savers. They are VERY tiny and delicate. When it comes time to mount the motors and prop savers, have a steady, gentle hand....or find someone who does.

Have fun!

Cliff
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Old 02-10-2012, 03:29 PM   #6
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Originally Posted by JetPlaneFlyer View Post
If you know the weight and wing area and it can be worked out, near enough.

V = √( 2 W g / ρ S Clmax )
where:
V = Stallspeed M/s
ρ (rho) = air density KG/M^3 (about 1.2 kg/m3)

g = 9.81 m s^-2
S = wing area M^2
Cl_max = Max Coefficient of Lift
W = mass KG


Or, a simplified approximate calculation in ‘old units’ =
stallspeed = 5.25 * √wing loading

speed
in mph
wing loading in oz/sqft



Steve
I'm impressed...but what Maybe when I was in school 50 years ago my friend Anyhow, even if I could work that out into actual mph or kph, what would that look like in the air? Let's just go with the fact that I can do a very fast walk, or a slow jog, and still keep up with my GWS Cargrtrans at its slowest airspeed.

Cliff
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Old 02-25-2012, 03:09 PM   #7
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Default Thank you Cliff.

I finally finished modifying it to brushless, power wise. Weight came out at 22 oz. with no battery. Used a Nano Tech 2200 mahr for thrust testing & rpms. RTF weight is now 23 oz.
Thrust @ takeoff is 38 oz ....prop speed @ T O is 44 mph.
I am winding the GWS HD 5 x 3 x 3 blades pretty high at about 14,000 rpm.
It will pull vertically out of my hand. 22 amps at WOT.
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Old 02-27-2012, 08:24 PM   #8
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Yikes! 28oz! Well, you certainly have enough power to fly.

Mine is completely stock, 4 brushed motors, 64 watts total, 16.8oz AUW.

With your weight being almost double mine...all bets are off as to the slowest safe speed. The plane does have a large wing, so it should handle just fine though.

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Old 02-27-2012, 10:44 PM   #9
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Default Ho ho ho !



Bad addition.
Plane is 17 0z. with no battery. I am using a Turnigy Nano Tech 2200 ma 3 cell. Total weight is 23 ounces RTF.
Battery is 6 oz.
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Old 02-29-2012, 03:57 PM   #10
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Originally Posted by cyclops2 View Post


Bad addition.
Plane is 17 0z. with no battery. I am using a Turnigy Nano Tech 2200 ma 3 cell. Total weight is 23 ounces RTF.
Battery is 6 oz.
Whew, glad to hear that. 38 ounces was pretty porky. I really enjoy flying the Transport. Looks very realistic in flight.

I'm thinking about pulling the wheels off mine though to add to the realism, especially since I handlaunch and land on grass anyhow.

Cliff
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