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Old Jul 21, 2005, 09:59 PM
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Western Montana
Joined Mar 2005
357 Posts
Stork 2 Pro-E: Mild motor ?

This is my first post and thought I'ld get my feet wet by commenting on this very nice plane I've been flying for the last year and a half. The setup is: Hacker B50 11S/6.7 GB, GP 2200 (12 cells), Prop 20X12.
I chose the 11S because I started flying it with lipos TP 2100 (3s 3p). My thought being lots of extra mah to keep me out of trouble because this is my first glass 3 meter and I really didn't know what to expect. My other E-gliders are Poly Sergio, Fly-Q (Omega 1.8) Nike-2. I needn't have worried. I just fly for fun (my idea of a spot landing is noting the spot I have to walk to when it lands) and I know there are faster, stronger and lighter 3 meters but the Stork flies really, really well. After just a few flights with the lipos, they gave a solid 50 degree climb. I wanted more. So I ran some numbers through P-calc and decided to try a 12 cell. I'm not sure what the current numbers are because I ran the test with the new GP 2200 without having cycled the pack and I can tell they are much stronger now. The test went something like this. Plug in watt meter, grab tiny little nose cone (with B50 and 20 inch prop!!) firmly in both hands, have wife flip throttle switch creating instantaneous blinding hurricane-force winds, loss of balance. Lots of screaming and shouting that lasted an eternity of 5 seconds, turn off switch with shaking hands, jot down 70 amps/11.4 volts/800 watts, then run upstairs to change underwear. I will not do that again!
What struck me was those numbers are quite mild compared to typical 3 meter setups but when I checked the rpms (after firmly bolting nose cone to glider) it read 4500 which for that prop gives approximately 188 oz static thrust and 50 mph pitch speed and in-flight thrust of 129 oz or 8 lb for a 6 lb glider. With a hot battery the Stork will accelerate to pitch speed very quickly. My average motor run times are 6 to 7 seconds.
I know this is still a mild setup compared to the monsters I've been reading about but it is such a rush watching the Stork go vertical in such an aggressive manner. The only downside is it flies so well that by the time a second motor run is needed the battery is cold so subsequent climbs are 80 degrees or so but still just 6 to 7 seconds. Did I mention that I really like this glider?!!
Thanks for letting me share. David
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Old Jul 22, 2005, 03:26 PM
Launch high. Fly low.
United States, CA, Lake Elsinore
Joined Aug 2003
4,136 Posts
I've had that happen to me with the Graphite nosecone. I was holding the nose trying to put the plane together for a bench flight and suddenly the motor went full throttle for a few seconds. I thought I was gonna take off!!! the cone was slipping off til it idled down--- thank goodness. I think it was a glitch or interference from my wireless network or my cell phone-- I know i didnt hit the throttle stick since the tranny was way off to the side--- SCARY!!! almost peed myself, too.

Anyway, now I have the Stork 2 Pro also. Hacker B70s, 18x10 props. I usually fly it now with 8x3300s or 10x2200s. It seems to fly better with 8 subCs since theyre heavier. Where is your CG set up? What tranny are you using?

thanks,
jc
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Old Jul 22, 2005, 08:06 PM
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Western Montana
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Hi JCats. I was hoping some Stork 2 fliers would respond. This is really exciting to communicate with other fliers with similar interests. My CG is 104mm from the leading edge, centered under ballast tube which is what the facts sheet from Dieter recommended. This seems to be just right as it's stable yet signals lift well and in dive test will pull up gradually. The gear box is the one Hacker installs, max 6.7. I'm using Hacker 105 ESC and was concerned it might twist off the GB/motor connection with its instant on and hard brake but it has not. I have had trouble keeping the prop yoke on the shaft until I tried a tip from someone here (Soho, I think) and used Goop. Hey, I laughed too! But it works. I totally agree with your comment (it seems to fly better heavier). It flew well with the lipos but with the Ni-MH 12 cell it retains much higher energy levels, landings are safe and predictable while rising in lift is no problem. In fact, it's amazing to watch this 3 meter tank rise faster than my 20 oz floaters. With the extra weight and trailing edge reflex, she'll just rip across the sky so fast you had better be smooth on the sticks or bad things will happen!
So with your B50, what 6s or 9s? What is your climb performance and how does it compare to your graphite?

David
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Old Jul 22, 2005, 08:32 PM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
Got a link? I have a Classic Fortune, which is the same as the Espirt Stork..
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Old Jul 22, 2005, 11:21 PM
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Western Montana
Joined Mar 2005
357 Posts
Hi Andy, Espirt's Stork looks like a really nice plane and seems of high quality but I am not personally familiar with it. The Pro-E I do know to be very well thought out and is of high quality and seems to be quite different.

Stork -E
Airfoil RG 15
Wing area 930 sq in
Wing loading 13-14 oz/sq ft
Wing span 118.5
Length 55
Two-piece wing

Stork 2 Pro-E

Airfoil HN-3545M
Wing area 1061 sq in
Wing loaing 9.7 oz/sq ft.
Wing span 127.17
Length 59.06
Three-piece wing

It is hard to know if I'm comparing apples to apples with these specs but they are the sheets I had.

David
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Old Jul 23, 2005, 12:39 AM
Launch high. Fly low.
United States, CA, Lake Elsinore
Joined Aug 2003
4,136 Posts
David,

Your CG is at 104??? Mine is at 110 to 115!!! I keep hearing different CGs for this plane... I'm gonna start moving it forward to see how it goes.
I actually started flying ths stork with 10x2600/3300 and 12x2200. I found it too heavy since you really lose low altitude agility- you really have to set up for really long landing approaches and where we fly, we dont have a lot of room (trees on every side, soccer goals, some power lines etc) . The crow and flaps help a bit but you kinda lose more maneuverability. Now I fly it with 8 subC and 10x2200s and it feels comfortable. The 8 cell launches are nothing to write home about; the 10x2200 launches are better at about 80 degrees- 10 to 15 seconds to way past winch launch heights- maybe 5 to 600 feet.

Compared to the Graphite??? I like the Graphite better, much better. The fully molded graphite E was my very first moldie. I assembled that thing with no instructions-- i just asked and read around the forums. I was comfortably flying it less than a few flight hours. It's more stable and hundred times much easier to land- I used to land it by my feet all the time. It was comfortable with 12x3300s- it flew faster of course but it didnt lose low altitude maneuverability at all. fly it with 8 cells and your gonna fly for hours on a pack. I loved that plane! It was a present from the wifey, too.
But where is it you ask??? it's in the hills/trees somewhere in Boonton, NJ!!! hahahahaahahahah!!! The wings exploded at around 2 to 2400 feet trying to exit a thermal. The pieces fluttered all over the sky for 5 mins while i watched in shock and disbelief. We looked for parts for hours and couldnt find a single piece... Twas a very sad day indeed.
I like the storkie but given the opportunity and cash... i'll get the graphite 2 E and convert the stork to pure glider- my very first non-electric. I need a pure glider since the guys at my club fly mostly pure sailplanes and I want to join their competitions.

What tranny are you using?

laters,
jc
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Old Jul 23, 2005, 04:57 PM
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Western Montana
Joined Mar 2005
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Hi JCats,

Wow, your Graphite sounded great! I would love to see one fly some day. This Stork is also my first moldie. And I too had no trouble assembling it with no instructions, the layout was very intuitive. CG seems to be so personal. With mine set at 104 mm and trimmed for level flight all my control surfaces are at their neutrals. This is a very fast level flight which, as I said, pulls up from the dive test very gradually. But this thing is heavy. With the light polys it was 96 oz, with the 12 cell it is 105 oz. Though I notice no difference with its thermalling ability; in fact, it seems more forgiving. I will often fly with reflex, crossing the sky at high speed, until I see it signal lift and more often than not, by the time I add camber and turn to find the thermal, I will have already gained 50 feet. As far as the extra weight for landing, I must confess I am spoiled rotten. We live surrounded by thousands of acres of open land so approaches are not too much of a problem. But even with that my approaches are steep and very controllable and I often have to force it down quick because I can hear a thermal coming up behind me and I don't want to get tossed on the landing. Do you mix flaps and ailerons? I do. It seems to work really well with crow, much increased control.
Back to climb rate, I truly don't understand why my heavy glider climbs so well. Altitude maybe? (We are at 4500 ft.) But that large prop pulls it to 500 to 600 ft in 7 seconds. (Varified with a Picolario.) So whereas I have no other moldie to compare this to, I am really happy with its performance.

Sorry for rambling...

David
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Old Jul 24, 2005, 12:26 AM
Tragic case
davidleitch's Avatar
Sydney Australia
Joined Feb 2002
5,870 Posts
I flew my Stork today on 12xgp2000 and an 18x11 prop after the previous pack (14xgp2200) vented whilst charging.

Either my scales are wrong or you guys have a different layup to me as I believe my all up weight is under 90 oz even with the 14xgp2200.

I've been flying mine for over a year now and really enjoy it.

There's no doubt that a big 3 metre moldie in a strong thermal, whizzing across the sky with giant loops is a great thrill.

The 12x gp2000 still give a good climb and a nice lighter feeling in the air. Actually came up short on the landing today as the energy retention was less than I was expecting.
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Old Jul 24, 2005, 09:25 AM
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Western Montana
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David, glad you picked up on this thread because you fly your Stork in competitions, you probably have more experience with it than anyone else here. Reading your posts have always been very informative. My scales might very well be off (they are just kitchen scales); but I do feel the Stork flies better with the extra weight of the 12-cell pack compared to the 3s3p and it is primarily in the area of energy retention. But even on landings it just seems to be more stable on a steep approach and less likely to veer off. And even at the lighter weight I was never comfortable working low lift. The fun of having a 3 meter is getting up to where the lift is stronger.

On your current set up, what is your climb rate and pitch speed? I'm just curious because the numbers I got from testing my system don't seem to jibe with its vertical performance. Also, you have flown against many other types of molded and other gliders, how does it compare? Do you feel it is still competitive?

David
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Old Jul 25, 2005, 06:21 AM
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Sydney Australia
Joined Feb 2002
5,870 Posts
David

I reweighed mine tonight and with 14xgp2000 I am at 88 oz. Adding a 4xgp1100 receiver pack has increased the weight compared to the previous UBEC. I wasn't comfortable with the UBEC when using 14xgp2200 because the current was 130 amps.

Certainly the measured climb with the 14xgp2200 was up towards 4000 fpm from memory. Need to get the lolo out and remeasure. It was like a rocket but I felt I was straining the gearbox which was only designed for that power level for very brief intervals.

I've only had one flight on 14xgp2000 and the climb was a comfortable 80 degrees, appropriate for anything except all out competition. Using the latter pack the wing loading is around 12 oz sq ft still up about 20% on unballasted F3J setup.

Certainly the advantage of the bigger planes is working the lift higher up and also being able to get to the lift. I may build another 14xgp2200 pack for windy days.
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Old Jul 25, 2005, 09:02 AM
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Western Montana
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David, WOW 88 oz! with receiver pack! I also use the receiver pack 2100 4 cell because I could not get a clear range check using the UBEC. I think I found part of my discrepancy on my performance numbers. When I flew yesterday I remembered to take the tac out with me and checked the prop and it was getting 4980 rpms; which is substantially more than my first test. That should put my pitch speed at somewhere just under 60 mph but I am curious, if there are any mathematicians out there, as to APPROXIMATELY how many watts are required to spin a 20 X 12 prop that fast.

David
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Old Jul 25, 2005, 02:24 PM
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Salem, OR
Joined Sep 2002
884 Posts
Hi Guys!
I've owned a Stork 2 Pro E for some time now. I think I was the first person to blow the wings off it in the US over Hells Canyon. (before he put CF center pannel in!) Anyway, I'm having great fun with this plane and it's wide flight envolope is what makes it nice for me.

I'm flying it with an Aveox F12, 17X10 prop, on 10 GP 3700's. She's pulling about 82 amps as tested this weekend. Somewhere I have an altimeter track of a launch but I can fly her better now so I'll have to do it again. I"ll look to see if I can find that SS if you are interested.

She's going pretty much vert, well more like 75-80 degrees in no wind. I was out climbing a Stratos a friend of mine has during an electric TD contest weekend before last and he keeps his setups pretty hot! I love how well she can slow down and almost be floaty with a little undercamber. I suspect the stork does not have the energy retention that the Stratos has but haven't gone loop to loop with one yet to test that theroy, just seems that way to me.
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Old Jul 26, 2005, 07:23 AM
Tragic case
davidleitch's Avatar
Sydney Australia
Joined Feb 2002
5,870 Posts
There are different layups on the Stork of course, and that probably accounts for the weight difference.

The energy retention issue is so different to be sure about unless the wingloading is equal. Energy retention on the Stork varys depending on how much battery is in it.

One day if I win the lottery I'd like to put it up against the Jaro Mueller's newest ship the Espada.

I think all of us Stork fliers would agree that its one of the easiest planes to do the radio installation on you could ever imagine. All the servos just screw in, excellent recesses for the supplied wiring connectors, perfect fit of all the parts.

Big thanks to Shredair for popularising this plane, on this forum at least.
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Old Jul 26, 2005, 09:29 AM
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Western Montana
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Frankswd, thanks for posting. So what WERE you doing over Hell's Canyon!?

When I talked to Dieter during my purchase of the Stork he said he clocked a beach run somewheres around 130 mph and I have no doubt that it will achieve those speeds very rapidly. I do have my doubts whether it will stay in one piece. With reflex on I have hit turbulence while zooming around the skys and have seen quite a bit of wing flex. I have done 4 consecutive loops without losing much altitude, but that really doesn't say much.

Now from what I can tell all of you appear to be running a smaller prop at a higher rpm. I am trying to understand the benefits. Does the smaller prop create less drag when it is folded? Or is the pitch speed so much higher that it is worth running the higher amps with the related stresses? Sunday I had a 10 second climb, full vertical to 800 ft, not much lift, messed around for 10 minutes, did a fast, low fly by, another 10 second vertical climb, messed around another 12 minutes, did another 7 second climb full vertical and could just start to feel the battery sag a little bit. To me that seems nice (?).

David
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Old Jul 26, 2005, 09:59 AM
Launch high. Fly low.
United States, CA, Lake Elsinore
Joined Aug 2003
4,136 Posts
..."Or is the pitch speed so much higher that it is worth running the higher amps with the related stresses?"
From what I understand, the smaller the props the lower the amps. With my 10x2200 pack I get 4 to 5, 10 to 15 second launches at around 70 to 80degs to 500+ feet. 500+ feet is more than enough to catch thermals. So I guess my preference is more launches rather than higher launches.
I have flaps mixed in with ailerons but i rarely use it. aileron+rudder and elevator+flaps are always on.
My storkie seems to nose down a bit while circling thermals-- what would cause this???

jc
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