Ryanfan

My Feedback: (1)

I'm new to eletric flight. I would like to convert my GP Ryan STA 1.20 ARF to electric ( SORRY< I should have calrified this when I first posted this). I've used MotoCalc to size/select components. I'm finding it hard to locate the manufacturer(s) of the motors/gearbox(s) suggested.

I would like to get confirmation of the selections before I buy something that turns out to be wrong for the application., or unobtainable.

The ARF is new in the box. I just obtained it from another RCU member. This makes any modification possible without having to unbuild or replace fuel soaked parts. (I mention this because I plan on converting my Midwest Livewire Champ and have found despite careful attention to fuel proofing, some areas will have to be cut out and replaced)

I plan on flying fully aerobatic. Our field (STARS-Syracuse) is well manicured grass.

As I mentioned, I'm new to electric flight, but not glow. My spare time is very limited hens the move to ARF and electric. My family appreciates it too. Since I was last actively flying, battery technology has gained in leaps and bounds. Back then, NiCads were simple- fully discharge before recharge to avoid memory build up. Charge slowly. New batteries every spring. The NiCad days seem to be almost gone.

I need help understanding the available battery technology, and the proper care and hygene that goes along with it. I almost burned up my dad's car 30 yrs ago charging a rc car in the front seat from the cigarette lighter. Fortunately our club has electricity now.

I look forward to getting this project off the ground in a couple of months.

Thanks for all of your input.

HA

Hello Ryan fan!

Had on myself, great flyer!

Motor..................Axi 282010 on 8-10 17-2400 mah nicads or 3s2p Lipo

Phasor 30/3 same as above


Prop..................10/7 APC or Aeronaut



If you want to go Aerobatic go with the 10 cell or, better, with the Lipo
It will take off from grass and will be mildley aerobatic with 8 cells
Flight time will be about 8 minutes-- 15 minutes with the Lipo.
Almost forgot ESC: JETI : ADVANCE PLUS 40

All the items can be obtained from HOBBY LOBBY or the like

I would suggest you read up on battery care and charging, especially on the LIPO,
which will need a dedicated charger, get one that has at least 5 amp capacity, such as the ASTRO.
However NiCads are still a good and less expensive choice

Hope this helps............have fun!

HA

Hello Ryan fan!

Please disregard my previous reply, I was thinking of the smaller, lighter Ryan EP.
Your plane's weight is 10.5 lbs.

I would suggest the Axi 4130/16 with the Jeti 77amp Esc. And start with a 14-10 prop
24 cells Nicads should do it, or use two Lipo's, 4s2p.

That will give you about 1000 watts +, depending on the prop you use.
All up weight with Nicads will be about 13.5 lbs, or 1 lbs less with Lipo's.
Wing loading about 25 oz/sq ft.

This will give you lots of power and performance.............if your wallet can stand it!!

Have fun
Ha.

Ryanfan

My Feedback: (1)

Thanks HA. Yep, I corrected the description in my posting.

I've looked at the AXI's.

MotoCalc doesn't list AXI among the manufacturer selections that come up even after downloading an update. Don't take this say that if it's not on their list I won't look at it.

How about gearing? MotoCalc lists most at approx 6:1. There is a Aveox 1817/4Y listed at 2:1, and a huge 18x12 prop.

I've included the following data:
MotoWizard Results - Great Planes Ryan STA

Desired Full-throttle Performance: Aerobatic
Minimum Partial-throttle Flying Time: 13 minutes

Number of Motors: 1
Wing Span: 82.5 in
Wing Area: 1066 sq.in
Empty Weight: 160 oz
Airfoil: Medium Semi Symmetrical

Elevation: 420 ft
Sea-level Pressure: 29.00 inHg
Air Temperature: 85°F

Drive System Types: Direct Drive or Geared
Motor Types: Brushless Only
Manufacturer: Hacker
Maximum Number of Cells: Any Number
Cell Types: LiPoly Only

Motor Battery Gear Prop Rating

Hacker B50 14XL 12x1950Li 6P 6:1 16x10 1.000

Generated by MotoCalc 7.09, 6/4/2005 4:54 PM.

There are over a 100 results if I don't pick at least a few restrictions. Hacker comes up the most often though.

bhouin

My Feedback: (106)

Ryanfan,

Motocalc lists the AXI series motors under the manufacturer Model Motors.

Ryanfan

My Feedback: (1)

Thanks for pointing out my oversight. Like I said, I'm new here.

Ryanfan

My Feedback: (1)

OK.

I lookaed at Model Motors/AXI.

All of the choices that MotoCalc returned were rejected due to thermal, inefficiencies,etc.

In other words, MotoCalc doesn't find AXI as a suitable choice for this project.

Next?

Ryanfan

My Feedback: (1)

The AVEOX 1817/4Y(2:1), and Hacker B50/C50(6:1) come back as the best matches. Hacker appears multiple times with several prop choices.

I've searched for the AVEOX on line but can only find their home page and a write up on tow planes.

Anyone know where these (AVEOX) are available and the gear box?

bhouin

My Feedback: (106)

Ryanfan,

One thing to remember, I don't think that the 53xx series AXI motors are listed in Motocalc. To use them, you would have to individually add the appropriate information from the manufacturer. It would seem that one of them would fit this size plane, but there are others here that would be able to tell you for sure.

HA

Hello Ryanfan!

As you can see there a lots of motors that would do well, it becomes a personal preferance.
Also keep in mind that Motocalc is limited and has gaps.
The old rule of 70 watts per pound is still a good measure to use. With all the info available,
flying and trying out different prop combination is the best way to go.
Why go with a gearbox, just another possible problem and expence!
Hacker however ,is certainly a top rated motor.
A direct drive outrunner, simple and lots of tourqe, would be my choice.

Hobby Lobbys catalog has a full run down, including spec's and prop suggestions, on a verity of motors!

Have fun, and yes it is dificult to make a choice!

HA.

Lokihaus

My Feedback: (8)

Hello all. I've been researching an engine for my GP Ryan STA EP for sometime now, and have not come to a conclusion. I don't know alot about the engines that aren't of a popular brand type. Like people talk about engines and all these numbers and letters and it just turns me off. What I would love is people posting links that go directly to a store's inventory of each item! That'd be awesome!

So can someone point me towards an engine/speed controller setup w/ batts that would work well on the Ryan STA EP? Thanks!

tahustvedt

I looked at this plane on the GP website and they recommend a .61-.91 2-stroke, or .91-1.20 four stroke. That's the exact same recommendation as my Edge 540 and I'm flying it with the following equipment. I also posted the addresses to the shops where I bought mine:

APC 17x10E propeller (E for electric) http://www2.towerhobbies.com/cgi-bin...?&I=LXEYH1&P=7
AXI 4130/20 Motor (biggest of the 41xx-series) http://aircraft-world.com/shopexd.asp?id=2402.
8S1P PolyQuest 4000 mAh batteries (two 4S1P 4000 packs in series) http://aircraft-world.com/shopexd.asp?id=2859.
Hacker Master 77 O (Jeti Advance PLUS 77 Opto is an alternative) http://aircraft-world.com/shopexd.asp?id=2115.
Koolflight UBEC 45 V (supplies power to the receiver from the main batteries instead of a separate receiver battery) http://www.koolflightsystems.com/ultimatebec.htm

Reading:
44.24 A
26.59 V
1176.3 W

This gives me close to unlimited vertical with this 8.8 lbs plane. I get at least 15 minutes duration, probably 20 when flying sedate. I used just 835 mAh out of 4000 in a 4.5 minute sedate flight the other day, including a few full throttle vertical climbs. I have only flown it twice so far but I expect it to give me lots of fun times. The big prop sounds great and would probably look good on such a big Ryan STA. I have a video of it if you want to hear the sound. I haven't confirmed the capacity of the battery, nor do I know for sure if it is going to last long as I have only used it a few days. The smaller Jeti Advance PLUS 45 Opto and similar Hacker ESC are cheaper than the one I suggested, but I preferred some overhead so that the ESC runs cooler, and in case I wanted to upgrade the motor/battery later. I chose the 45 V UBEC version for the same reasons, even though the 35 V version will do.

The test-data on Hobby-Lobby isn't always correct, and neither is Motocalc, especially with AXI's.

Ryanfan

My Feedback: (1)

The only issue that I have with the AXI 41XX is thermal capability.

I've seen a few posts where the motor failed due to thermal build up. In particular on an H9 P51 that Sean Plummer has written up on RC Groups. The set up is almost identical to the one you have posted. MotoCalc also points toward thermal problems.

I fly at close to sea level- 410ft. and temperatures at or above 90deg.f and rh close to 100%

I have been looking at the newer and larger AXI 5 motors though. These may have some promise.

It looks like a direct drive out runner is out of the question. These all fail on thermal and operational inefficiencies. The prop size is too large as well. The only acception is an Aveox 1817/4Y motor. Otherwise most combinations come in at around 6:1 reduction and a 16" prop.

tahustvedt

Calculating from a 3-view, the scale prop size for the GP Ryan Sta 120 is 16" if you use the wingspan as reference, and 17" if you use the fuselage length as reference.

I think the 53xx AXI's are heavy but the plane is big so it shouldn't be a problem. The problem with the 53xx in this plane is that they have a very low rpm so I don't think they will be useable with such a small prop unless you use a lot of cells. The 4130 is rated for bursts of 60 A for 30 seconds. With the setup I posted it pulls less than 44. Mine doesn't get hot even after the video flight which had a lot of full throttle flying, but I have only measured the can, not the internal components. I'd have to take off the prop, spinner and cowling very fast to access them. I have only used mine for a few flights. I'll be really disappointed if it fails since I'm running it far from the limit. You'd get 110 W/lbs with this setup if it ended up at 10.5 lbs.

The Mustang Sean Plummer converted was a 1.50 made for 1.20-1.50 2-stroke. Much more powerful than the GP R-STA which is for a .61-.91. Or am I thinking of a different plane?

How is the structure on the STA? Is it lightly built?

Ryanfan

My Feedback: (1)

That's the correct one.

BTW- Thanks for the input.

As far as the build, it's built fairly light, but there's little opportunity to lighten it further w/o de-constructing it. It's 10.5 lbs bare. I would like to add some scale details that will add some weight- 6-8 ozs. including flaps. I will add the flying wires for static display only. The reason for the flaps is the plane looks like it will be a little hot on landing without them. My SIG Ryan w/ HP .61 was easier on final with a little flap.

I plan on balancing the plane by moving the radio/servo components and battery placement. I don't want to add anyting if I absolutely don't have to.

As far as the prop size, it doesn't have to be scale. I'm more concerned with performance, and clearing the dirt when the tail comes up. A 16-10 prop fits with the majority of the selections from Motocalc.

I submitted both AXI and Hacker data from MotoCalc to HL as well as the plane data and desired flying characteristics for evaluation but haven't received any feed back yet. The info is posted earlier in the thread.

There is also quite a bit of difference in $$$ depending on the setup. I agree on the esc though. AXI or Hacker, the jeti is the winner. I still like the idea of independant receiver batteries though. That might be just a hold over from years of experience and an unwillingness to try something different. Experience can breed complaciency. I can be persuaded though.

Lokihaus

My Feedback: (8)

Okay, sorry all... I might have messed some people up... I know I messed up myself, but initially I was thinking that we were talking about the GP Ryan STA EP, this one...

http://www2.towerhobbies.com/cgi-bin...?&I=LXBFL9&P=7

But in fact Ryanfan was talking about the larger version, this one...

http://www2.towerhobbies.com/cgi-bin...?&I=LXVK73&P=7

My bad!

So, HA... you would recommend the first set up you talked about in your first post as a good setup for the lighter EP?

Motor..................Axi 282010 on 8-10 17-2400 mah nicads or 3s2p Lipo

Prop..................10/7 APC or Aeronaut

If you want to go Aerobatic go with the 10 cell or, better, with the Lipo
It will take off from grass and will be mildley aerobatic with 8 cells
Flight time will be about 8 minutes-- 15 minutes with the Lipo.
Almost forgot ESC: JETI : ADVANCE PLUS 40

Thanks, and sorry for any confusion!

bhouin

My Feedback: (106)

Ryanfan,

Using your numbers and the mfg information for the 5300 series AXI's, it looks like the 5320 series might be good choices for you. If you pm me your email, I can send you the information for the 5300 series for motocalc and you can take a look.

HA

Hello Lokihaus!

Yes,my first recommendation for the Ryan EP is a good one, especially with the Lipo.

By the By I never had any overheat problems with the AXI motors, even when going over
the recommended amps and or voltage. Also one should remember to use the throttle stick,
it is not necessary to run full out all the time!

Have fun!
HA

Ryanfan

My Feedback: (1)

This is an update of my data from about a month ago. I entered the AXI 53XX series data and came up with this combination. Cost looks good as does performance. Nothing against Hacker, just more than is needed for this project (and extra $$$). I don't see this plane doing hovers or or torque spins that I could get from the Hacker combinations.

Motor: Model motors axi 5330/24; 197rpm/V; 1.5A no-load; 0.057 Ohms.
Battery: Thunder Power TP1950; 12 series x 5 parallel cells; 1950mAh @ 3.7V; 0.015 Ohms/cell.
Speed Control: Jeti Advance PLUS 90 Amp Opto; 0.001 Ohms; High rate.
Drive System: Generic 15x10in Prop; 15x10 (Pconst=1.31; Tconst=0.947) direct drive.
Airframe: GP Ryan STA 1.2; 1066sq.in; 260.6oz; 35.2oz/sq.ft; Cd=0.048; Cl=0.46; Clopt=0.6; Clmax=1.11.
Stats: 82 W/lb in; 74 W/lb out; 30mph stall; 41mph opt @ 66% (97:09, 135°F); 47mph level @ 73% (82:46, 139°F); 1331ft/min @ 21.5°; -350ft/min @ -5.5°.

I'm looking for some help on the battery cell count vs the ESC allowance. The JETI 90 says up to ten cells, but I'm within the amp rating. Then about the batteries themselves and a charger(s) to accommodate them. Thunderpower is fine. Just the size.

Thanks.

Awall

My Feedback: (2)

More information to chew on...

To get the most performance out of the motor, you will need to prop it with a 17x10e and run a 6s lipo. You will be drawing 45-58 amps at full throttle, running around 1000 watts. Make sure to allow for good ventalation to your motor, esc and battery!!!!

This setup has been used on the Flinton Extra, Miss America P-51 and BME Cap 232. Your plane will have a heavier AUW than these latter planes ( around 11-12 lbs ) . Randy Green at Hobby Lobby said they use this setup to produce 12lbs. of thrust. I'm using it in a Great Planes Giles 202, 59", 7.5lbs. Flies sport/aerobatics but no all out 3D. It appears that you could reach a little over 1:1 thrust to weight on your 12 pounder... especially if to could drop a few ounces on the conversion. 83 watts/lbs. would fly this thing well.

Have fun!!

Tweet

My Feedback: (1)

Ryanfan, I think the 5320/28 will be a nice motor for this airplane if you can swing the right size prop.

On the ESC you have to be within the Amp and voltage rating. So, if the limit on the ESC is 10S and you want to use 12S then you are out of luck. You could take a look at the new Castle Creations High Voltage ESCs which are rated to 12S.

For the battery...12S5P. Tons of flight time. Kind of problematic with the TP selections without a complicated harness. Here is their web site. http://www.thunderpower-batteries.co...batteries.html

10S4P would be easy to do using two 5S4P in series. 12S2P would also be easy to do using two 6S2P in series. You know, for this airplane I would think you would be able to get more than enough performance (unlimited vertical) with a 10S setup if you use the right prop and the 10S4P setup would give you around 25-30 minutes of spirited flying.

bhouin

My Feedback: (106)

Ryanfan,

In your setup that you listed, your 12S5P will not work with the current Jeti esc's as they have a 10S limit (as pointed out earlier). Also, the other issue with a 12S5P in your plane would be excess weight. With your setup, you are createing a plane that is going to be over 16lbs rtf based on the 260oz in your post.

Here are some thoughts: an 8S2P TP 2100 setup on an AXI 5320/28 using either a Jeti 70, 77 or 90 and a 17x10e prop. Or as suggested, a 6S2P TP 2100 setup on an AXI 4130/16 using a Jeti 70 or 77 esc and a 15x10e prop. It just depends on how you intend to fly the plane and your budget as to which setup you would choose.

Also, I did some rough calcs on the weight that you supplied, you provided an empty weight of 160oz. The planes estimated rtf weight from GP is up to 11.5 lbs. Using this as a base and subtracting out the weight of an OS 120FS with muffler I get an empty weight of 150oz. Now this doesn't take into account the removal of the fuel tank and plumbing and the throttle servo, so you might see another 5-10 oz off from this to create your baseline weight. I used a baseline of 150oz in the motocalc runs listed here.

What do others think about these options? I am sure that there are many here with significantly more experience than me to validate or invalidate these options, as I am still on the short end of the learning curve with electrics.

It will be interesting to see what HL replys on your emails.

Here is the motocalc info for these setups:

Motor: Model Motors AXI 5320/28; 249rpm/V; 1.5A no-load; 0.0057 Ohms.
Battery: Thunder Power TP2100; 8 series x 2 parallel cells; 2100mAh @ 3.7V; 0.022 Ohms/cell.
Speed Control: Jeti Advance 70-3p Opto; 0.003 Ohms; High rate.
Drive System: 17x10 (Pconst=1.31; Tconst=0.95) direct drive.
Airframe: GP Ryan STA; 1066sq.in; 202oz; 27.3oz/sq.ft; Cd=0.054; Cl=0.47; Clopt=0.72; Clmax=1.24.
Stats: 88 W/lb in; 84 W/lb out; 24mph stall; 32mph opt @ 63% (44:16, 86°F); 39mph level @ 75% (34:24, 92°F); 1564ft/min @ 34.2°; -272ft/min @ -5.6°.

Possible Power System Problems:

The full-throttle motor current at the best lift-to-drag ratio airspeed (39.5A) is lower than the motor's maximum efficiency current (79.2A). A higher current level would improve system efficiency.
Current can be increased by using more cells, a larger diameter or higher pitched propeller, a lower gear ratio, or some combination of these methods.

Aerodynamic Notes:

The static pitch speed (60mph) is within the range of approximately 2.5 to 3 times the model's stall speed (24mph), which is considered ideal for good performance.
With a wing loading of 27.3oz/sq.ft, a model of this size will have flying characteristics suited to the intermediate pilot, for use in calm to moderate wind conditions.
The static thrust (192.9oz) to weight (202oz) ratio is 0.95:1, which will result in very short take-off runs, no difficulty taking off from grass surfaces (assuming sufficiently large wheels), and steep climb-outs.
At the best lift-to-drag ratio airspeed, the excess-thrust (113.3oz) to weight (202oz) ratio is 0.56:1, which will give steep climbs and excellent acceleration. This model should be able to do consecutive loops, and has sufficient in-flight thrust for almost any aerobatic maneuver.


Motor: Model Motors AXI AC4130/16; 390rpm/V; 1.8A no-load; 0.063 Ohms.
Battery: Thunder Power TP2100; 6 series x 2 parallel cells; 2100mAh @ 3.7V; 0.022 Ohms/cell.
Speed Control: Jeti Advance 70-3p Opto; 0.003 Ohms; High rate.
Drive System: 15x10 (Pconst=1.31; Tconst=0.95) direct drive.
Airframe: GP Ryan STA; 1066sq.in; 183.2oz; 24.8oz/sq.ft; Cd=0.054; Cl=0.47; Clopt=0.72; Clmax=1.24.
Stats: 67 W/lb in; 52 W/lb out; 23mph stall; 30mph opt @ 55% (39:22, 90°F); 37mph level @ 65% (28:43, 97°F); 938ft/min @ 20.7°; -259ft/min @ -5.6°.

Power System Notes:

The full-throttle motor current at the best lift-to-drag ratio airspeed (38.4A) falls between the motor's maximum efficiency current (19.4A) and its current at theoretical maximum output (105.7A), thus making effective use of the motor.
The voltage (19.5V) exceeds 12V. Be sure the speed control is rated for at least the number of cells specified above.

Aerodynamic Notes:

The static pitch speed (58mph) is within the range of approximately 2.5 to 3 times the model's stall speed (23mph), which is considered ideal for good performance.
With a wing loading of 24.8oz/sq.ft, a model of this size will have trainer-like flying characteristics. It would make an ideal trainer, for use in calm to light wind conditions.
The static thrust (111.8oz) to weight (183.2oz) ratio is 0.61:1, which will result in short take-off runs, and no difficulty taking off from grass surfaces (assuming sufficiently large wheels).
At the best lift-to-drag ratio airspeed, the excess-thrust (66.1oz) to weight (183.2oz) ratio is 0.36:1, which will give strong climbs and rapid acceleration. This model will most likely readily loop from level flight, and have sufficient in-flight thrust for many aerobatic maneuvers.

Tweet

My Feedback: (1)

Ryanfan,

Also you asked about chargers. I feel the best readily available charger for the $$$ right now is the Astroflight 109. The new high capacity TP chargers look good, but aren't available and of couse have no track record.

Good luck.

Ryanfan

My Feedback: (1)

I haven't received a reply from HL, so I went to their web site and the have a GP RYAN STA 1.20 listed in their conversions section now.

They went with the 4130/16 set up that you also posted. I'm curious why Motocalc kicked out this combination for thermal overload. HL's conversion has different battery and prop selected also.

I'm resubmitting to them now. My ambient conditions might be the answer. It was 95 here again today. They might agree.

tahustvedt

Here's a thread of someone converting this plane with the setup I suggested earlier, AXI 4130/20, only with Ni-Mh batteries instead of lipo.

http://www.rcgroups.com/forums/showthread.php?t=254012