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Old Jul 29, 2011, 07:31 PM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
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At the same time--why are we building scale airplanes? So that they look like the real thing? Sounding like the real thing isn't such a bad thing... Not to me, anyway...
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Old Aug 03, 2011, 08:33 AM
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Joined May 2003
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Herb,
After reading your thread, I got got one and it flies great. I had the same' landing bounce' until I increased flaps to 45 degrees and held some power on landing. I used E-Flites electric retracts (drop right in) as my Spring Airs were in my E-Flite F-86. I am using a Wemo Fan as I have had 2 Chinese fans loose some blades. best 90mm plane I have ever had and god knows I think I have flown most out there. My only complaint is that I had it flip over in 25 mile winds on landing and cracked the canopy and trying to get a replacement from Nitro has been the typical TCW (the chinese way)
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Old Aug 04, 2011, 12:26 PM
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Herb's Avatar
Irvine, Calif USA
Joined Feb 1999
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Glad to hear about your success !

The WeMotec fan combination sounds like a winner for this plane. I would not drop too much flaps (esp not in a turn !!) on the T-45 as it blanks out the elevators. I land mine without flaps now, I don't think this one needs them - apart from looks.

Also, flaps reduce the max AoA so they make the Hawk easier to stall, that's a well known issue for the turbine Hawks. You need a flat glide with flaps deployed.

You might want to consider adding wing fences. I keep seeing reports of CMP Hawk tipstalling on banked landing approaches. Maybe they had the wrong CG as well (too far back, making them a bit too pitch sensitive), who knows.

Somebody should pull a plug off of that canopy (Ken Sparks / Parkflier.com) ! Getting replacements from CMP could be a nightmare.

http://www.nitroplanes.com/canopies.html


.
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Old Aug 04, 2011, 07:24 PM
"My grandma wants to fly jets"
heychas's Avatar
Richmond, VA
Joined Feb 2008
471 Posts
Great thread Herb... thanks!

Isn't that hawk landing w/ flaps down and at a slightly nose high AoA? Its been a while since I've had a class in aerodynamics but if I recall correctly, flaps down should increase the max AOA. I lost a good friend because he pulled his flaps up after take-off before turning to avoid an airport. Flaps were required in the turn due to the slow airspeed... resulted in a tip stall.

With all that said, it is hard to argue w/ your experience w/ this plane
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Old Aug 05, 2011, 12:39 PM
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Irvine, Calif USA
Joined Feb 1999
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Can't find a good reference, but here's one:

TE flaps increase the camber of the wing which increases the CL MAX, but the greater curvature means the airflow separates at a lower AoA because it simply cannot make the sharper turn (as BEagle pointed out, the CL curve moves up and slightly to the left). This is true for TE devices that only increase camber (Spilt and Plain Flaps). More efficient flaps that also increase boundary layer energy (Slotted and Fowler Flaps) raise the CL curve even further and help to maintain the airflow to the wing at even higher CLs. Fowlers being the most efficient flap types also increase wing area.

The effects of LE devices depends on the type of device. A device that increases boundary layer energy (Slots and Slats) extends the CL curve, allowing a greater CL Max and an increased critical AoA. If the LE device increases camber only (Kreuger Flaps), then it does not extend the CL curve, but does move it up and to the left (having the same effect that TE flaps have). Slats increase the BLE and also the camber therefore extending the CL curve and raising it as well.

Next time I pull out my aerodynamics book, remind me to wear a dust mask :O


http://www.pprune.org/archive/index.php/t-126007.html

In short, flaps reduce stall speed but make the wing aerodynamically less "clean" - potentially promoting an earlier boundary layer separation.
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Old Aug 05, 2011, 12:53 PM
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Irvine, Calif USA
Joined Feb 1999
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Here one can find more than one (I) wants to know .

The discussion here is specific to the total loss of a turbine JetLegend Hawk on the maiden, after putting down too much flaps on the landing approach :

http://translate.google.com/translat...awk%2BErstflug

Assuming that one understands exactly what went on there, the message seems : do not start out on the maiden with excessive flap deflection ...

.
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Old Aug 07, 2011, 07:53 PM
"My grandma wants to fly jets"
heychas's Avatar
Richmond, VA
Joined Feb 2008
471 Posts
Thanks for the info Herb... that's great! I can't remember if simple scale aircraft like the Cessna 150 or 172 have trailing edge flaps or the better flaps. Seems there would be some advantage to TE flaps. I'm putting split flaps on my NP starfire in hopes to keep if from floating all the way down the runway... in this case they may be more like speed brakes I'll probably try using the full open position w/ crow. The goal is to control the glide slope w/ the throttle rather than guessing my airspeed.
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Old Aug 08, 2011, 01:12 PM
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Irvine, Calif USA
Joined Feb 1999
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Glad it made sense, it did so to me ... sometimes subtle issues are involved, such as: how do you define the AoA with flaps extended etc.

I had two flights with the T-45 this last Saturday, on the first one I slowed it down so much on landing that it started, nose up, to go a bit unstable It was quite windy too, 15mph+ I think.

I dinged up the nose bottom which required some bondo work.

On the second flight, the left main came out only when I hit the ground on landing , I think the strut might have bent a bit on the previous landing. At least a badly scraped wing bottom was avoided at the very last second.

.
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Old Aug 08, 2011, 05:11 PM
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United States, CA, San Jose
Joined Jan 2007
325 Posts
Wing fences

Hi Herb
I'm trying to cut some wing fences like yours. (I spent lot of time making the little VGs, but made a mess on the wing instead..... haha) so I decide to make wing fences. What thickness of styrene sheets should I use?
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Old Aug 09, 2011, 12:27 PM
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Herb's Avatar
Irvine, Calif USA
Joined Feb 1999
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I'd say 1/32 (1mm) ply, styrene or fiberglass sheet. The styrene sheet is by far the easiest to work with, you can just cut it with a scissor ...

I think this Hawk definitely needs the wing fences
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Old Aug 10, 2011, 06:55 PM
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HI
stall landin during my 28th fly !!!!!!!

T 45 CMP decrochage à l'atterrissage (6 min 23 sec)
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Old Aug 10, 2011, 07:07 PM
"My grandma wants to fly jets"
heychas's Avatar
Richmond, VA
Joined Feb 2008
471 Posts
Great video Vengame! It didn't look like a stalled landing from my perspective, but just a tired nose gear But you were there so you would know best.

Herb - sorry about your scraped up nose and broken landing gear.
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Old Aug 10, 2011, 07:37 PM
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Irvine, Calif USA
Joined Feb 1999
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Nice video, have to try that myself ! Can you post a picture on how you mounted the camera, mine is a bit too tall ? Maybe you made a hole in the fuse?

Lat weekend I had both flights with the strobe on, nobody would notice it until I told them I had a strobe on the fuse top It's that blinding Ca afternoon sun.

I did not damage the retracts, they are fine ... remember they are Springairs Just a scraped nose.

The good news is that mine went like stink with a new 8S pack
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Old Aug 12, 2011, 07:07 AM
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Joined Aug 2011
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I've set up two elastic on the door of the turbine and shut the door (screw) the camera and held only by two elastic and is based on a piece of foam

here is my camera:

http://www.hobbyking.com/hobbyking/s..._5MP_CMOS.html

escuse me me for my very bad English
THANK YOU for this fantastic HERB about to discuss, which made ​​me buy the T-45 CMP
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Old Aug 22, 2011, 03:13 AM
Tin Can Sailor
seadog985's Avatar
Alabama, USA
Joined Feb 2009
761 Posts
are the freewing retracts going to hold up?
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Last edited by seadog985; Aug 27, 2011 at 02:46 AM.
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