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Old Sep 24, 2012, 12:12 PM
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Have to agree, the STA is a bit heavy and draggy with the rigging. I have gotten rid of some excess weight, but I like the rigging and the drag it causes doesn't seem to be that much of a bother. I have flown two different models and both flew acceptably right out of the box, although improvements can be made. Yes, there is a lot of elevator there and I have fallen off to the side on a few loops. I would blame getting a little too slow at the top for this. That big elevator does come in handy for keeping the tail down while operating in thick grass.
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Old Sep 24, 2012, 05:11 PM
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Germany, near Stuttgart
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Quote:
Originally Posted by vtdiy View Post
Weighed mine. With my 1300mah 3S batt in it it weighs 27 ounces. Yikes! My Brown Racer, A little larger weighs 20. Where does that extra 7 ounces come from? The last owner did put a pilot and a big toggle switch in the cockpit. Those will be jettisoned.

I pulled the steel ballast weight out of the nose. Pulled the rigging off of the tail and upper wing so far. That stuff alone weighs about an ounce and a half.
.....

Looking at the wheels, they are both too small for my grass field -- I'm sure -- and look quite heavy. I think I'll trade them for larger diameter foam wheels. There is plenty of room in those wheel pants for a bigger wheel. I bet the foam ones are lighter.
......
Noticed what looks like a lot of downthrust. Not sure if that has been increased by the crash this plane apparently had. But reading the thread about the diving tendency on hand launch, I think the downthrust is excessive, out of the box. Low wing planes generally don't need much downthrust, unlike high wing cabin jobs.
Wow! 27 ounces/ 765 gram thats heavy. Look for details at my post =60; mine weights 695 gr / 24.5 oz. Where does this come? To much epoxy when it was repaired?
Take the screws out in the back and glue the elevator & rudder with CA. You will save at least 0,3 ounces at hull ends. This effects that i can use 2.200 mAh lipos and have to pull them back nearly 15 mm back from the bulkhead! Mine weigths so a little bit more than 27 oz; flies great, is not a racer.

The 55 mm wheels from the artec Spitfire fit perfect. I use this too. Here you can save total 10 gr./ 0.4 oz. But wheels with more diameter than the origin can't be mounted in the Rayan's wheel pants -> you have to sand the the screw-housing with a dremel and so 55 mm is the maximum possible diameter. Starting out of grass ist no problem, but landings often end with a noseover at least .

My Ryan has no downthrust, perhaps half a degree. At wing's end i fitted a 1mm balsalayer behind the wing screws to get a little bit higher angle of attack, CG is on the upside wing struts. Just like written, she is no racer and i fly her most with 50 - 60 % throttle ... flighttime and fun = enough .
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Last edited by Pramus; Sep 24, 2012 at 05:14 PM. Reason: since 40 years still training english .....
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Old Sep 24, 2012, 06:02 PM
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Old Sep 24, 2012, 06:23 PM
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Hey Fravits, Pramus -- good to hear from you both!

On the loop falloffs Fravits, the other cure, I know, is to go more gently on the elevator if throws are high. Too much throw and too quick acts as a brake, which does slow the plane, as you sday.,so its possible to keep a lot of throw for landings, but apply less rapidly in the loop. I guess I'll know what I prefer myself on this plane after flying it. The spitfire didn't suffer from reducing throws a little, and loops really nicely now. In fact, climbs straight up with an 11x7 two blade prop.

I could still add back rigging -- but it will be fishing line, not wire and springs and screws.

Pramus, I think another contributor to weight on this particular plane is paint. Looks like yours is natural foam white except for trim. The blue and orange version is spray painted on all surfaces. Also I'm not sure how much this pilot and toggle switch weighs because I haven't taken them out. Could be a heavy pilot.

I can't imagine that there is enough epoxy on the wing repair (a single break) to make much difference to weight. I don't know if the prop is original -- it could be heavier.

I'll take your advice on the wheels -- I actually have the Artech Spitfire wheels, since I increased the size of those on that plane, and took the old ones off.

The downthrust is very pronounced on this one -- maybe a result of foam crushing at the bottom. I'm not sure. But it looks wrong. I will add plywood and re-mount the motor with a very small amount of downthrust.

Your plane looks great!!
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Old Sep 25, 2012, 03:40 AM
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Mine was blue and yellow and I decided to go the silver and yellow route. I wish I had weighed prior to painting. i did sand the fuselage rather well and added a couple of coats of WBPU to seal it up. Then I sprayed some silver auto enamel. No doubt some weight was added, but I did lose some getting rid on the ballast in the nose. Then again, adding the flap servos didn't help the weight any, but the flaps do slow things down nicely. I'll get it on the scales as soon as I have finished the details, hopefully this week.

Nice to see some people on this thread!
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Old Sep 25, 2012, 05:59 PM
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Fravits, mine is blue and orange, not even yellow.

Would really prefer aluminum and yellow or all aluminum -- I've searched hard trying to find a photo online of a blue and yellow full size PT-20 but haven't seen a single example painted that way. All I found were aluminum fuselage versions.

I think the model manufacturer must have confused it with the Fairchild PT-19.

I guess if I painted the fuselage silver, the orange would look closer to yellow without the blue complementary color next to it. But I have to see how the weight goes down first -- and fly it.

I removed the motor screws last night but the motor was glued in place....?! Maybe another crash repair. Well I'll be adding a ply bulkhead so I'll pry it off.
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Old Sep 25, 2012, 08:25 PM
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Got the motor off, and another surprise. Man it's heavy! For a little CDrom type motor, similar in proportions to the 1.7 oz Towerpro 2408-21, it weighs in at about 2-1/2 oz.

I may be a little off there -- I'll have to locate my digital scale instead of the kitchen scale, but that's quite a bit. I checked an Emax CF2822 on the same scale and it came out to 1-1/2 oz -- a savings of an ounce. Yet the little emax motor will put out 24 oz thrust with an 8x4 prop.

The Emax motor only costs $7.95 at headsuprc.com. Should take any Ryan of about that weight vertical. And also improve efficiency in normal flight for longer flight time with a smaller (and lighter) battery. I'm thinking of making the swap.

Not only that, but the CF2822 draws 12 amps static -- so the 30 amp ESC on board the Ryan is also overkill. An 18A ESC might be okay if the specs are accurate. And that would reduce weight even further. I'll probably stick with the 30 A unless I turn up a smaller (and lighter) one in my parts box.

EDIT:

More info: The stock motor is described as a D3128 1100kv. I can't find any reference to that motor online, except in reference to the Ryan. HobbyKing does carry a D3128 1550kv motor. But that's quite a lot faster.

I think this motor is really heavy, and probably not very efficient. It looks like it was intended to be a high wattage motor, but was de-rated for this application. I doubt it is putting out as much thrust as the Emax, although running at higher amperage.
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Old Sep 25, 2012, 09:24 PM
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Out of curiosity, I just weighed the plane as it is now (ballast removed, 1300mah 3s batt moved forward, some of the rigging removed, motor removed) and piled the Emax CF 2822 motor on, and the spinner, and a new GWS EP8040 prop in place of the very heavy original 8.5" prop.

Weight is now just over 23 ounces. Almost 4 ounces lost! And I still haven't changed the wheels, or removed the lower rigging.

Thrust to weight ratio should now be 1 to 1 with the new motor and prop. Total expenditure so far $7.95 + $0.95 for prop

Also, re.painting: I tried a little low tack masking tape on the paint surface of the fuselage and ripped it off. It took a good spot of paint off. So with regular masking tape, I should be able to remove the fuselage paint, and can re-paint with aluminum.
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Last edited by vtdiy; Sep 25, 2012 at 09:30 PM.
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Old Sep 25, 2012, 09:27 PM
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United States, TN, Knox
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HK Ryan STA EPO build

I really admire the work of you fellows who can post those great build descriptions with nice pics. Here, I'm just going to put up some photos of my model taken along the way to it's present state. Photos of it's current state will be included also. If possible I'll come back and edit the posts to better describe them and answer any questions. Additionally, I'm plan to post an "unboxing video" on You Tube when it is sufficiently edited. That will show more of what the model looked like just out of the kit box... unboxed!
Photo Descriptions:
#1-HK Ryan STA EPO -Silver repaint (over stock blue bits) with a light dusting of Krylon Metallic Brilliant Silver. I decided to leave the blue paint on as a protective layer to reduce the chances that the Krylon would damage any naked exposed foam. Plus, sanding looked like a lot of extra work. So far, the Krylon seems to be holding up to handling reasonably well, and the looks are OK for me.
#2-HK Ryan STA EPO -Stock Main landing gear wheel on scale w/ 9.1g readout.
#3-HK Ryan STA EPO -The other stock Main landing gear wheel on scale w/ 8.3g readout!
#4-HK Ryan STA EPO -Stock Main landing gear axle on scale w/ 1.6g readout (a lighter substitute of carbon fiber or aluminum wouldn't be hard to find).
#5-HK Ryan STA EPO -DUBRO Super Lite Wheels 2" Dia. used for Main landing gear wheels
#6-HK Ryan STA EPO -DUBRO Main landing gear wheel on scale w/ 6.5g readout
#7-Turnigy Nanotech 2200mAh battery on scale w/ 189.2g readout
#8-HK Ryan STA EPO -Standard HK-supplied prop. on scale w/ 11.5g readout
#9-APC 0906E prop. on scale w/14.0g readout (described by other builders as a good replacement for stock prop.)
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Last edited by pegasus.pony; Sep 26, 2012 at 03:07 PM. Reason: Photo descriptions
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Old Sep 25, 2012, 10:07 PM
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United States, TN, Knox
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HK Ryan STA EPO build

Second group of photos:
#1-HK Ryan STA EPO -ESC placement modifications: ESC moved from front inside fuselage cavity to outside under motor cover.
Also note: nose weight has been removed.

#2-HK Ryan STA EPO -ESC placement modifications: front view
#3-HK Ryan STA EPO -ESC placement modifications: bottom view
#4-HK Ryan STA EPO -ESC placement modifications: bottom view 2
#5-HK Ryan STA EPO- interim mod. state
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Last edited by pegasus.pony; Sep 26, 2012 at 08:44 PM. Reason: Photo descriptions
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Old Sep 25, 2012, 10:12 PM
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Great info Pegasus, and your paint job is going to look just right!

If I were keeping the stock motor I'd be tempted to try the GWS EP9050 over the APC -- it is considerably lighter than even the stock prop. Still haven't found my gram scale, but I bet it weighs nearly half of what the APC does.

Of course what you end up using will be influenced by your weight distribution. If you can get that larger battery forward of the usual fwd location, that will help. I can fit my smaller battery vertically in the cowl area, which really concentrates the weight up front.

Took the pilot and toggle switch out just now. Another half ounce saved.

I also realized that there was a plywood firewall sandwiched in the foam. And now can see that this double layer plywood was shattered by impact! Amazing that the motor shaft wasn't bent, and that there was no apparent foam damage in the nose area. That explains the excessive "down thrust" and the glued in motor......

I'll have to consider how to deal with this problem...
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Last edited by vtdiy; Sep 25, 2012 at 10:18 PM.
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Old Sep 25, 2012, 10:26 PM
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Oops, just realized these are older photos, of the build, and yours is already completed.
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Old Sep 25, 2012, 10:31 PM
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United States, TN, Knox
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HK Ryan STA EPO build

Third photo group:
#1-HK Ryan STA EPO -exhaust pipes RH fuselage. Pipes made from plastic straw. Diameter a little large but OK for me now.
#2-HK Ryan STA EPO -Carved pink foam pilot bust. He's a bit chunky but claims to be an expert pilot... I haven't weighed it yet.
#3-HK Ryan STA EPO -Carved pink foam pilot bust
#4-HK Ryan STA EPO -AVIATION FUEL ONLY decal, serial number placard decal, black-painted FrogTape wing root strips
#5-HK Ryan STA EPO -AVIATION FUEL ONLY decal, close-up
#6-HK Ryan STA EPO -serial number placard decal, NO STEP decal, black painted Frog tape wing root strips
#7-HK Ryan STA EPO -LIFT/MOOR decal, NO PUSH decal
#8- HK Ryan STA EPO -LIFT/MOOR decal
#9-HK Ryan STA EPO -Carved foam pilot bust, serial number placard decal, black painted Frog tape wing root strips
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Last edited by pegasus.pony; Sep 26, 2012 at 08:47 PM.
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Old Sep 25, 2012, 10:43 PM
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United States, TN, Knox
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HK Ryan STA EPO build

Fourth photo group:
#1-HK Ryan STA EPO - Wing underside w/ flap servos, Frog tape , LW Wheels, Exhaust pipes, paint
#2- HK Ryan STA EPO -LH Wing underside w/ flap servo, Frog tape to cover servos wires/channels
#3-HK Ryan STA EPO -RH Wing underside w/ flap servo, Frog tape
#4-HK Ryan STA EPO-replacement wheels, wingroot paint, exhaust stacks, covered (filled) exhaust ports (LH side)
#5-HK Ryan STA EPO -Cockpit equipment bay, 2200mh battery inserted
#6-HK Ryan STA EPO -Cockpit equipment bay, 2200mh battery inserted, Spektrum AR6100e receiver
#7- HK Ryan STA EPO- Cockpit equipment bay w/ Rudder/Elevator servo mount tray
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Old Sep 25, 2012, 10:59 PM
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United States, TN, Knox
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HK Ryan STA EPO build

Fifth photo group:
#1-HK Ryan STA EPO -Nose detail w/Additional cooling air inlet, ESC air inlet,
motor axis offset , filled/covered LH exhaust ports
#2-HK Ryan STA EPO -Nose detail w/Additional cooling air inlet, ESC air inlet,
motor axis offset
#3- HK Ryan STA EPO- Nose detail
#4- HK Ryan STA EPO- motor axis offset detail , black painted FrogTape tread strips on wingroots, NO STEP decals
#5-HK Ryan STA EPO-motor axis offset detail
#6-HK Ryan STA EPO-motor axis offset detail, exhaust pipes
#7-HK Ryan STA EPO- Serial number/ID placard decal , carved pink foam pilot bust
#8-HK Ryan STA EPO- Serial number/ID placard decal
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