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Oct 05, 2020, 10:03 AM
GOT WINGS
siriusflier's Avatar
I finished putting the PT-17 together yesterday, did a range check, and tried ROG on the road in front of my house. Everything seemed to work well, but ran out of time and didn't get to set COG. A quick check showed it to be very tail heavy even though I tried to get as much weight forward as I could. I put boards in the cross struts on the outside wing struts for stiffening, and now the outsides of the lower wings curve down a bit. Wonder if that will be a problem? Here are a few photos of the mostly finished product:
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Oct 05, 2020, 09:36 PM
Dance the skies...
Tom Frank's Avatar
My comments in RED
Quote:
Originally Posted by siriusflier
I finished putting the PT-17 together yesterday, did a range check, and tried ROG on the road in front of my house. Everything seemed to work well, but ran out of time and didn't get to set COG. A quick check showed it to be very tail heavy even though I tried to get as much weight forward as I could.
I had to cut out the fire wall on mine and extend the battery through it until it almost touched the back of the motor! And that was about a decade ago with an EPS foam plane, heavy NiMh cell flight packs, and no glassing! Whatever you do, don't try a test flight with a tail heavy plane. It sounds like you may need to drill some holes in the fake radial engine and glue some lead weights in them for balance? Or maybe some larger and heavier wheels? I recall I put on larger dia. rubber tread (not foam like the light wheels on yours) wheels, too. Another option is to cut off the tail wheel and add a lighter weight tail skid?

I put boards in the cross struts on the outside wing struts for stiffening, and now the outsides of the lower wings curve down a bit. Wonder if that will be a problem?
I don't quite get what you did with "boards in the cross struts" Did the lower wing slope slightly down to begin with (warped maybe?)
Last edited by Tom Frank; Oct 05, 2020 at 09:41 PM.
Oct 05, 2020, 11:00 PM
GOT WINGS
siriusflier's Avatar
I don't plan on trying to fly the plane until I get the COG close to the leading edge of the bottom wing. This evening I worked on moving weight forward. First, I had trimmed the fuselage so that I could use a 3S 1300mah battery. I tried a 3S 2200mah battery and cut the inside of the battery compartment so that I can shove that battery almost all the way to the front of that cavity. Then I replaced the 5.7 gram fake motor with a 35 gram cowl that I made for my T-6. That made the COG close, but I still may have to add a 21 gram lead weight.

What I am calling the cross struts are the center section of the wing struts that go from the front to the back struts. In this photo, they can be seen at the far side of the wings and are almost vertical. I took them loose and the wing straightened out. So I shortened those middle pieces of the outside struts about 5millimeters. The wing still curves down a bit on the outside, but it is not nearly as bad. Not sure if I can shorten them anymore without making new pieces.
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Tried to weigh the plane yesterday, but my scale only goes to 500 grams. Today while I had the landing gear, prop, and cowl off I weighed all the components and came up with 560 grams or about 20 ounces without the battery. The battery weighs 169 grams, or about 6 ounces.
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Oct 19, 2020, 02:37 PM
Right Rudder
PittSpecial's Avatar

After almost 8 long years, I finally got another GWS PT-17 Stearman!


Okay,

I am back in the saddle again with a prospect for a brand new -in-the-box GWS PT-17 Stearman!

Really excited as I have seen pretty much ALL offerings from those other brands and I just know that the GWS Stearman is a majestic RC bi-plane model that can actually fly scale (slow) and people can actually see what passed them.

The other models are nice with lots of scale details plus shock absorbing struts etc...etc...., however, there is nothing like a GWS PT-17 Stearman!

Paid a little more than $55 US plus shipping but, I know it is a quarter of what the other brands are asking and to me it is well worth it.

A few pictures from eBay!
Oct 19, 2020, 05:01 PM
Dance the skies...
Tom Frank's Avatar
Quote:
Originally Posted by PittSpecial
Okay,

...there is nothing like a GWS PT-17 Stearman!
...
...UNLESS, it's a GWS big Tiger Moth! I've flown both, both look very scale like in the air. But, with the PT-17 being notoriously tail heavy requiring some kind of user accomodation, like heavier battery moved way forward, heavier wheels , or worse, dead weight for balance. The Tiger Moth on the other hand can fly with a much lighter wing loading with just a 1300 mAH 3S lipo pack, and is just as realistic in scale-like flight. When you feel like it, it can also do some mild aerobatics that PT-17 cannot. Just my biased view... YMMV. At least there are a still very few GWS PT-17 kits around. Enjoy!
Last edited by Tom Frank; Oct 20, 2020 at 12:30 AM.
Oct 19, 2020, 07:38 PM
Right Rudder
PittSpecial's Avatar
Quote:
Originally Posted by Tom Frank
...UNLESS, it's a GWS big Tiger Moth! I've flown both, both look very scale like in the air. But, with the PT-17 being notoriously tail heavy requiring some kind of user accomodation, like heavier battery moved way forward, heavier wheels , or worse, dead weight for balance. The Tiger Moth on the other hand can fly with a much lighter wing loading with just a 1300 mAH 3S lipo pack, and is just as realistic in scale-like flight. When you feel like it, it can also do some mild aerobatics that PT-17 cannot. Just my biased view... YMMV. At least there are a still very few GWS PT-17 kits around. Enjoy!
I appreciate your inputs, however, back in 2003 is when I acquired my very first and only (as of yet) GWS PT-17 Stearman flying model.

Even with borderline Center-Of-Gravity issues while experimenting with (at the time) AstroFlight 010 Brushless in gearbox setups and trying out (Lithium Polymer technology at the time) the model handled very well without uncontrollable issues that you are discussing here.

I almost always try to keep all my scale models as light as possible and they are very forgiving as a result.

For those others visiting and watching this thread, I like to point them to Posts # 93 & # 94 as yes, (guapoman2000 was my old handle here) and you can see that I have extensive experience with this model and it's flying characteristics. During my ownership and behind the controls of my GWS PT-17 Stearman, I was able to perform all sorts of maneuvers with it. I would say, mild sport maneuvers but, the model is capable of them.

https://www.rcgroups.com/forums/show...dup-Tips/page7

However, TOM, like to thank you nonetheless.....

EDIT: Post # 154 from the same build / discussion thread listed above, I posted the recommended Center-Of-Gravity from the manual in case anyone has any doubts.......

Last edited by PittSpecial; Oct 19, 2020 at 08:03 PM.
Oct 19, 2020, 07:54 PM
Right Rudder
PittSpecial's Avatar

Video to prove my original GWS PT-17 still flys!


For those wondering what happened to my GWS PT-17 Stearman model, I gave it to my friend Mark who demonstrated a flight just over one year ago on June 31st, 2019 over at my RC Club!

It still flys delightfully......

GWS PT-17 Stearman Brushless with scale 3D Engine 06-30-2019 (1 min 37 sec)
Oct 19, 2020, 11:19 PM
Dance the skies...
Tom Frank's Avatar
Quote:
Originally Posted by PittSpecial
I appreciate your inputs, however, back in 2003 is when I acquired my very first and only (as of yet) GWS PT-17 Stearman flying model.

Even with borderline Center-Of-Gravity issues while experimenting with (at the time) AstroFlight 010 Brushless in gearbox setups and trying out (Lithium Polymer technology at the time) the model handled very well without uncontrollable issues that you are discussing here.

I almost always try to keep all my scale models as light as possible and they are very forgiving as a result.

For those others visiting and watching this thread, I like to point them to Posts # 93 & # 94 as yes, (guapoman2000 was my old handle here) and you can see that I have extensive experience with this model and it's flying characteristics. During my ownership and behind the controls of my GWS PT-17 Stearman, I was able to perform all sorts of maneuvers with it. I would say, mild sport maneuvers but, the model is capable of them.

https://www.rcgroups.com/forums/show...dup-Tips/page7
...
However, TOM, like to thank you nonetheless.....
Greetings! Like you, I first flew acquired the GWS PT-17 back in 2003. It was my first electric-powered RC plane in fact. I flew it with the stock brushed motor and gear box using NiMH batteries. With that set up, the plane was not overly tail heavy to the point of causing any serious controllability issues.

It was only when I converted to brushless outrunners, and especially 3S LiPo battery packs, that the tail heaviness became an issue. I never flew it so tail heavy that controllability was an issue, but I eventually had to cut out an opening in the firewall so the 1300 mAH battery pack could be slid forward far enough to get good balance. I figured anyone building a new one these days would NOT use the original power system in lieu of modern outrunners and LiPo packs, hence the concern for being tail heavy, as well as having to adapt an outrunner to the planes stick mount thrust line. My blog shows how I was able to adapt the gearbox frame to hold an outrunner (special stick mounts for outrunners were just showing up then). I eventually had to cut out an opening in the firewall so the battery pack could be slid forward far enough to get proper balance. Eventually I built a new nose section that extended the motor forward slightly enough good balance. A heavier outrunner would also be a solution, but that would overpower the plane and make it heavy for the way I like to fly it.

I used a CG location similar to what you showed, and it flew well. I especially liked the gold wings (they came stock painted that way then as you probably know) against a clear blue sky... so much so, that I painted my replacement GWS big Tiger Moth wings similarly!

The only point of my post was that I found the Tiger Moth overall lighter and more nimble, and I enjoyed it's flying characteristics even more. It was also easier to convert to modern outunner/LiPo power systems. I still have the Tiger Moth and it's one of my favorites. I wish GWS hadn't gone belly up so there would be a replacement available if I ever crash it beyond repair. If you haven't built or flown one, I'd recommend it if you can ever find a kit these days. If you don't want it, let me know!

Happy flying!
Oct 20, 2020, 01:49 AM
Dance the skies...
Tom Frank's Avatar
Quote:
Originally Posted by PittSpecial
For those wondering what happened to my GWS PT-17 Stearman model, I gave it to my friend Mark who demonstrated a flight just over one year ago on June 31st, 2019 over at my RC Club!

It still flys delightfully......

https://www.youtube.com/watch?v=udjs_IXNN9A
Thanks for the video. Here's a link to my maiden flight with the PT-17 17 years ago. This is near and dear to my heart since it was also my first RC plane flight. I was flying it OK (looks a little bit tail heavy, in spite of the large real rubber wheels I had on it for balance), then I looked away to keep my daughter from running after it, and I lost it looping in the sun. Turn on your sound !

The PT-17 is a burly beast that can take a beating and survive!
Oct 20, 2020, 02:54 AM
Right Rudder
PittSpecial's Avatar
Tom,

Video is private.

Take care.
Oct 20, 2020, 09:24 AM
MN WATTS Master
Vintauri's Avatar
Wow seeing this thread revived gave me some nice nostalgia! Great to see a few of these still flying.
Oct 20, 2020, 10:55 AM
Right Rudder
PittSpecial's Avatar
Quote:
Originally Posted by Vintauri
Wow seeing this thread revived gave me some nice nostalgia! Great to see a few of these still flying.
U Betcha!
Oct 20, 2020, 06:52 PM
Dance the skies...
Tom Frank's Avatar
Quote:
Originally Posted by PittSpecial
Tom,

Video is private.

Take care.
Ah GEEZE! That's for the heads up! I don't normally post anything on YT. I clicked on it before and it played OK, so I didn't notice the Private tab. It should be fixed now!
Oct 29, 2020, 02:14 AM
Registered User
markdam's Avatar

whew 3 days


well i also bought one of the ebay pt-17s and ive been reading this thread for thee days and 2 decades!! im looking forward to building it and using all the tips 2 decades has taught me reading this thread....
Oct 29, 2020, 06:12 AM
Right Rudder
PittSpecial's Avatar
Quote:
Originally Posted by markdam
well i also bought one of the ebay pt-17s and ive been reading this thread for thee days and 2 decades!! im looking forward to building it and using all the tips 2 decades has taught me reading this thread....
Well, seems like you are ready to get that PT-17 put together and lets see your progress right here!


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