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Nov 27, 2015, 11:07 PM
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Eflite UMX PT-17 Conversion to a UMX PT-23A "Pegasus" - 1S Test Flight


Working on another UMX PT-17, this is the Test Flight of my experimental 1S UMX PT-17 Conversion to my rendition of a UMX PT-23A.

Eflite UMX PT-17 Conversion to a UMX PT-23A "Pegasus" - 1S Test Flight (3 min 26 sec)

RC Groups Initial Blog Write-Up Process with Photos: https://www.rcgroups.com/forums/show....php?t=2549654

Using the 2nd UMX PT-17 "Pegasus" in my fleet, I've decide to experiment with her as a test candidate for my UMX PT-23A Conversion. Being a single-wing Primary Trainer, she is a much faster 1S UMX Plane vs. the UMX PT-17 due to the reduced drag from the lack of the Top Wing. Although she has one less wing, her floaty and slow flight characteristics are still prevalent with this Conversion.

As most of the fields I fly at are currently encased under snow and ice, I chose to fly at the nearest thawed Track and Field location. Conditions at the field at 3:55pm were at a frigid 11 degrees F. Wind conditions were very mild with an average wind of 2.5 mph and a gust range of 3.9 mph. Using (2) of my Miniaviation 1S 3.7V 220MAH 45C Lipos, I was able to get 1-2 minutes of flight time out of each battery, as I normally would reach 5-6 minutes per flight. The chill was quite numbing to my fingertips and slowed down my tactile feel and reaction time. However, my newly converted UMX PT-23A was successfully airborne and flying smoothly and responsively, with an excellent roll rate due to her newly installed dedicated servos on each aileron. I removed the single feeble aileron / bell crank system and installed (2) Spektrum 2.3 Gram Linear Long Throw Offset Servos in its place, enhancing the Roll Authority.

Although this Test Flight was quite frigidly punishing, it provided me with the information I needed to satisfy my curiosity; I really just wanted to see if she would fly at all. In turn, Pegasus did more than that, and displayed excellently smooth and reactive flight characteristics, as well as gentle landing traits. If the weather was not so frigid, I'm sure I could open her up to more aggressive maneuvers that a 1S Brushed UMX Plane would allow.

With regards to some of those that have already commented about switching the Landing Gears to the Plated Clips Style and attached to the Wing.. that is actually an option that I am aware of and capable of doing, as I have those Wing-Style Landing Gears in stock left over from some of my other 1S Warbird Planes. As I am aware of the original UMX PT-17's excellent ground handling abilities and flight balance (even at the 2S Brushless configuration), moving the stout and well designed stock Landing Gears from their present location further aft on the fuselage and using the Wing-Style Landing Gears may result in a Ground Handling Balance which may result in an increased chance for nose-overs and prop strikes. Speaking of Prop Strikes.. using the Wing-Style Landing Gears will also result in a lower ground clearance which would not allow me to use any 5" Prop safely.. why would I want to shoot myself in the foot just so that it looks "scale?" At the present, I am currently in favor of keeping the Landing Gear configuration as it is despite the fact that it is not going to resemble "scale." As it is "my" version of the PT-23A, I would prefer creating an excellent-flying and outstanding ground-handling version of this plane, over the scale look. As always, should the plane come out better with the weight slightly further aft, I can always explore this option afterwards, as I do intend to convert this plane to 2S Brushless as well.

Future Developments: UMX PT-23A "Pegasus" is 2S Brushless-Ready - All of her Wing Surfaces as well as her Horizontal and Vertical Stabilizers have been reinforced with Carbon Fiber Rod Spars. As stated before, the Dual Servo Aileron System has also been installed as well. Wheels have been upgraded to the stout Hobbyzone Sport Cub S (Stock) Wheels. All that would be needed to perform the 2S Brushless Conversion at this time would be:

Eflite 180BL 2500KV Motor (Acquired)
Eflite 5 x 2.75 Prop (Acquired)
Eflite UMX Carbon Cub SS Long Prop Adapter (Acquired)
UMX Beast 3D Motor Mount w/ Firewall (Acquired)
UMX PT-17 Dummy Radial Engine Enlarged Hole (Acquired)
Eflite EFLU4864 ESC / Receiver AS3X (On Order - ETA 11/30/15)

The biggest decision to convert this experimental rendition of a UMX Fairchild PT-23A to a 2S Brushless System ultimately rested on this Test Flight.. and not only did she pass, but she also put a big smile to my partially frost-bitten face.

She will make an excellent 2S Brushless Speedster.
Last edited by Blaze0021; Nov 28, 2015 at 10:38 AM.
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Nov 30, 2015, 12:46 AM
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UMX PT-23A - 2S Brushless Conversion Complete!


After the successful Test Flight of my recently transformed 1S UMX PT-23A "Pegasus" (using my second UMX PT-17 for the single wing transformation), I've implemented the same 2S Brushless Conversion Process of my UMX PT-17 (2S Brushless with Dual Servo Ailerons) "Bella" and have converted the UMX PT-23A "Pegasus" into her 2S Brushless form!

Unfortunately its snowing here I Colorado and I don't see a Maiden Flight until we get some thawing...

Stay Tuned!
Dec 03, 2015, 10:48 AM
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UMX PT-23A (2S Brushless w/ Dual Servo Ailerons) - 2S Brushless Test Flight Update


As the consecutive sunny days have begun to thaw out Colorado and melt the layer of snow and ice from this past weekend, I found a snow-patched grassy field behind a large UPS staging warehouse with a large empty dry parking lot and managed to test fly this UMX PT-23A "Pegasus" conversion from a UMX PT-17, now with a 2S Brushless Configuration over the field.

Using the same battery placement as my UMX PT-17 (2S Brushless w/ Dual Servos) "Bella" (mid-placement within the battery tray), I found her to fly a touch nose-heavy, so I moved the Eflite 200mAh 30C Lipo furthermost aft to the back of the battery tray. I also moved her Elevator position to the 4th innermost hole (as compared to the 3rd innermost hole for my UMX PT-17 "Bella") which improved her pitch rate significantly. Moving the battery furthermost aft also relieved the nose-heavy feel.

After these initial adjustments, I took her up for another sortie for any further adjustments. All I can say is..

Wow.. this plane is fasssssst. much faster than my UMX PT-17 (2S Brushless) "Bella". With the lack of the additional bi-plane top wing and drag, the floaty lifting tendency has disappeared and my UMX PT-23A (2S Brushless) "Pegasus" now flies at a very unscale-like PT-23A with UMX Sbach air-splitting speed. Controls are very responsive but not touchy, which is a good thing. Rolling zoom climbs are easily achieved, and with maneuverability that gave me a thrill at the touch of the throttle.

Taking a few fly-by passes to get a feel of her slow flight capabilities as well as landing approach feel, I can say that while some of her slow flight capability has diminished, slow passes were still well within my control. Landings definitely come in at a much "hotter" speed as she would tend to "puddle-jump" on slightly uneven asphalt just a bit, even with the much larger Hobbyzone Sport Cub S Wheels. I am so glad that I went with my initial gut feeling and kept her Landing Gears in their stock position (as supposed to switching her to the more scale-appearance of using "clipped in wing landing gears) as the stock landing gear placement retained positive nose attitude during landings with no fear or sense of nose-tipping and prop striking.

I didn't realize until after landing that I had drawn a small UPS crowd watching from the warehouse of my impromptu test flight at their empty back parking lot. Upon touchdown , I heard a small applaud of clapping from the distance as a few of them had stepped out for their smoke break. One of them yelled, "Sweet plane man! That's the most excitement I've had today."

If David Lorenz Regional Park clears of more snow on the AstroTurf field today, I'll try to get some footage.

What a little speedster.
Last edited by Blaze0021; Dec 03, 2015 at 11:13 AM.
Dec 04, 2015, 01:58 PM
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While flying the PT-17 at Horizon Indoor I was mid-aired and it ripped the top wing off and creased the bottom wing. I managed to struggle it back to the ground since it had become very nose heavy.

Two small carbon rods later and moving the battery rearward significantly made it into a nice little performer even capable of knife edge and the roll rate with the top wing not there was nice.

Flew a little heavy on landing but is alot of fun, I can only imagine how yours goes being brushless.

Matt Andren
Horizon Hobby
Dec 04, 2015, 02:47 PM
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Quote:
Originally Posted by Mattfly
While flying the PT-17 at Horizon Indoor I was mid-aired and it ripped the top wing off and creased the bottom wing. I managed to struggle it back to the ground since it had become very nose heavy.

Two small carbon rods later and moving the battery rearward significantly made it into a nice little performer even capable of knife edge and the roll rate with the top wing not there was nice.

Flew a little heavy on landing but is alot of fun, I can only imagine how yours goes being brushless.

Matt Andren
Horizon Hobby
Hi Matt,

While that was an unfortunate turn of events for your PT-17, I do think that this accidental discovery proved to be a cool turnout on a new creation! That is a very interesting way to fit the spar on the wing and fuse on your version! Its almost like a Pawnee-Style Strut. And yes, you're absolutely right about the battery, as I used an Eflite 2S 180mAh 20C and moved the location further aft, behind the openings for the power cord. I found that placing the battery there yielded the best flight characteristics. I actually just finished obtaining flight footage today of my UMX PT-23A 2S Brushless with Dual Servo Ailerons "Pegasus" and I'll be uploading my flight video here this afternoon. She's a great performer, even in some nasty wind. Stay tuned! In the meantime, check out my other Horizon Hobby 2S Brushless Conversions. I've completed quite a few and the Blog Write-Up with the process should be in the descriptions: https://www.youtube.com/playlist?lis...BiE4PRLlaB4A7V

Thanks again for checking out my latest! More to come.
Dec 04, 2015, 06:31 PM
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Thread OP
Quote:
Originally Posted by Mattfly
While flying the PT-17 at Horizon Indoor I was mid-aired and it ripped the top wing off and creased the bottom wing. I managed to struggle it back to the ground since it had become very nose heavy.

Two small carbon rods later and moving the battery rearward significantly made it into a nice little performer even capable of knife edge and the roll rate with the top wing not there was nice.

Flew a little heavy on landing but is alot of fun, I can only imagine how yours goes being brushless.

Matt Andren
Horizon Hobby
Hi Matt,

The Video is done! Here is the Link: https://www.rcgroups.com/forums/show...2#post33362016

Full Flight Footage with Landing from 00:00s to 5:08s.
2nd Battery Aerobatic Extra Flight Footage from 5:09s to 7:07s.

Eflite UMX PT 23A (2S Brushless w/ Dual Servo Ailerons) "Pegasus" Premier Flight (7 min 7 sec)


Let me know what you think!

Thanks,

Derick


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