Seagull models 1/4 scale Shoestring racer

[firemanbill]

Well I took me a little trip down to Hodges Hobbies for their annual Electric fly in and had an absolute blast. I knew they had this in stock and new that I would have one sooner or later. After looking at it in the shop that became sooner rather than later!

This is one FINE looking aircraft! She is much sleeker that the old Great Planes model. Recessed servo pockets in the wing instead of the old standoff style. Two piece wing with hatch access for getting to the batteries. The old one had me limited to 8s batts due to space. Tons more room in this one! Could even go 10s if I want to. It also has a longer tail moment by almost three inches. Seems to be a lot more scale looking.

Looking at another Scorpion powered ship here controlled by a Castle HV ESC, Hitec metal gear high torque servos, JR DSMX radio gear, 7 ch rx with 2 satellites. 2 LiFE receiver batteries, EMCOTEC motor arming system... Nothing but the best is going into this one fellas.

She is going to be a rocket ship and she is going to be built right.

[gramps2161]

Sweet looking shoestring Bill are you gonna have it ready for for a ride to Georgia come spring?

[firemanbill]

That's the plan!

This one WILL be a success!

[firemanbill]

Coming along nicely. Servos installed in the wings and control rods in place. everything is hinged and tail section ready to go together tomorrow night.

Things I've noticed so far that I really like. Wing to fuse connector is really cool. Kind of a cam lock type deal built into the wing. Once it's slid onto the wing tube you rotate this mechanism 1/4 turn and it locks onto a pin on the fuse. No screws from the inside of the fuse.

Aluminum wing tube has some sort of fiberglass or rubberish type material inside of making it more sturdy.

Cowl is a very tight, snug fit. For a minute I almost thought it was too small to get onto the plane.

Hatch with spring loaded pins. Cool

Dislike - Cheap hardware control horns, typical of most ARF's. Will be replacing with heavy duty Dubro parts.

Overall so far I'd give it a 9 out of 10.

[gramps2161]

Bill sounds like your moving along on this one, and I can't agree more on the hardware with ARF's. I throw away the cheap plastic parts and buy new ones. Some control horns seemed like they were made out of hard plastic just waiting to break at the wrong time.
You also have to love the cheap plastic cleaves they give you bent more of them trying to get them to snap into the hole. That was enough to convince me to toss em, and go metal.
Have you decided on the motor you want with this Shoestring?

[firemanbill]

Got the horizontal stab all epoxied into place tonight, perfect alignment with little to no tweaking. I did add a could reinforcement braces on the bottom side of it to give it more meat to adhere to. Should have took some pictures but forgot until I already had it epoxied on.

Thinking of another Scorpion motor for this one. The old GP Shoestring had one in it and it worked really well.

[firemanbill]

Well, boy did the holidays get in the way this year! I can believe it's been so long since I posted in this thread, or worked on my plane for that matter. Sadly I have to admit that this is the first time I've ever had to clean the dust off of one of my current builds!

Anyway, she is all done now except for the motor. Radio gear is all installed with Hitec metal gear servos. all hinges double up and reinforced, I fill the gaps with trim monocote to prevent any flutter.

Getting ready to order my motor soon and while I'm waiting on that the Emcotec arming sytem is going in courtesy of my friend Thomas in Germany.

http://shop.rc-electronic.com/e-vend...&c=2263&p=2263

[firemanbill]

Here is a pic of the late, great, great planes Shoestring that went down in a blaze of glory at SEFF 2011, may she rest in pieces...

If you look close you can see some distinct differences between the two.

[gramps2161]

Hard to tell the difference between the two of them with the different angle pics.
Bill it does look sweet did they use a different color pattern on the bottom of the plane?

[firemanbill]

Originally Posted by gramps2161

Hard to tell the difference between the two of them with the different angle pics.
Bill it does look sweet did they use a different color pattern on the bottom of the plane?

It's all white on the bottom. I'm thinking of a couple black stripes on the wing to aid with orientation... But this plane goes fast and turns left so hopefully I will always be looking at the tops of the wings!

If the weather ever breaks I'll take String3, (an old GP version) still in glow form, down from the ceiling and do some side by side pics

[kyleservicetech]

Originally Posted by firemanbill

Getting ready to order my motor soon and while I'm waiting on that the Emcotec arming sytem is going in courtesy of my friend Thomas in Germany.

Which Scorpion motor are you planning on using??? Just looked at a couple of Scorpion motors, the units I looked at are claiming over 200 watts per ounce of motor weight. That motor is going to run HOT.

Hackers are in the same price range, take a look at their A60-16M, A60-5S, (Got both of them) and a couple of A60-XXL long case motors. These motors will run an honest 2500-3000 watts. They also do NOT use a propeller adapter for the motor shaft. Their motor shafts are threaded, like a big glow engine. The prop adapter can not come off, since there isn't one.
https://www.aero-model.com/8_72_909/...M/A60-16M.html
https://www.aero-model.com/8_72_907/...L/A60-14L.html

Great Planes Giant Big Stick Electric Conversion
http://www.wattflyer.com/forums/showthread.php?t=65052


I just made my arming system from Anderson Power Pole connectors, can do photos if desired.

[gramps2161]

Some black stripes on the btt. of the wing tip would help out even if this fast plane is only going left, could go left onto the other side real fast.

[gramps2161]

Originally Posted by kyleservicetech

Which Scorpion motor are you planning on using???

I just made my arming system from Anderson Power Pole connectors, can do photos if desired.

Denny I can make one of these easy, but how are you attaching it to the fuse. Did you make some kind of housing for the piece that is attached to the fuse?

[firemanbill]

Originally Posted by kyleservicetech

Which Scorpion motor are you planning on using??? Just looked at a couple of Scorpion motors, the units I looked at are claiming over 200 watts per ounce of motor weight. That motor is going to run HOT.

Hackers are in the same price range, take a look at their A60-16M, A60-5S, (Got both of them) and a couple of A60-XXL long case motors. These motors will run an honest 2500-3000 watts. They also do NOT use a propeller adapter for the motor shaft. Their motor shafts are threaded, like a big glow engine. The prop adapter can not come off, since there isn't one.
https://www.aero-model.com/8_72_909/...M/A60-16M.html
https://www.aero-model.com/8_72_907/...L/A60-14L.html

Great Planes Giant Big Stick Electric Conversion
http://www.wattflyer.com/forums/showthread.php?t=65052


I just made my arming system from Anderson Power Pole connectors, can do photos if desired.

Was thinking of the 4020-10 on 8s. It ran the old shoe great. Will look at the hackers. Good stuff they are!

I've already got that Emotec arming system, it is really cool, a magnetically activate inline switch. Remove the magnet, arm the system.

[gramps2161]

Bill is there a English version to that web site?

[firemanbill]

Originally Posted by gramps2161

Bill is there a English version to that web site?

If you use google chrome it has a translate button

[kyleservicetech]

Originally Posted by gramps2161

Denny I can make one of these easy, but how are you attaching it to the fuse. Did you make some kind of housing for the piece that is attached to the fuse?

I just took a piece of 1/4 inch thick plywood, sawed a notch into it that fits the AP connectors. Then cut a "plug" to fill the end. The attached photos show how it was done.

If you're using regular ply, not lite ply, simply drill two holes through the ply, thread it with a 4-40 tap, and hit it with CA. Wait for the CA to dry, and screw it to the side of your fuse.

This photo shows 8 AP connectors. These connectors are configured to allow four shorting plugs to wire the pair of 6S2P A123 batteries as a 12S2P for flight, and as a 6S4P for charging. Charging current is 30 Amps through a Cellpro PL8 charger.

When building this up, be sure to sand off the "nubs" off of the AP connectors with a very course piece of sandpaper. Glue it together with epoxy, nothing else. CA will migrate all over the place and make a real mess.

(Note that the pins in these connectors are a little rough in shape. That's from over 200 flights, plugging in a 12S battery pack to a Castle Creations 80 Amp HV ICE ESC.)

[kyleservicetech]

Originally Posted by firemanbill

Was thinking of the 4020-10 on 8s. It ran the old shoe great. Will look at the hackers. Good stuff they are!

I've already got that Emotec arming system, it is really cool, a magnetically activate inline switch. Remove the magnet, arm the system.

Just ran the numbers through www.motocalc.com on your Scorpion 4020-10 motor. Motocalc indicates the largest prop you can run with an 8S LiPo is an 11-6. With that the motor will turn the prop at 16,000 RPM, pulling 67 Amps, 1800 Watts at 27 Volts. The predicted motor temp is 320 F.

The 8020-10 motor is 80% of the size of the Hacker A50-12S that I've got. With mine, I've got an 16X8 APC-E prop on a 6S2P A123 pack. This combo works well, turning at 7500 RPM on the ground, pulling an 8 pound model straight up out of sight. Current is about 65 Amps, and watts is around 1200.

What's the wingspan, wing area and weight of your model? You'd likely need about 150 watts per pound of model to fly really well.

Thought about those reed relay arming systems. Would not take much to use a reed switch and a four 50 Amp FETS to make an arming system. Or, simply put in a small signal level toggle switch. Will have to try it sometime.

[JetPlaneFlyer]

The Scorpion S4020-10 is rated for 5s maximum.. RPM would be way too high on 8s

http://www.scorpionsystem.com/catalo...s40/S-4020-10/

[firemanbill]

Originally Posted by JetPlaneFlyer

The Scorpion S4020-10 is rated for 5s maximum.. RPM would be way too high on 8s

http://www.scorpionsystem.com/catalo...s40/S-4020-10/

I ran it for over a year on 8s in my old shoestring and even after the crash it lives on in another plane of my sons.

[JetPlaneFlyer]

Originally Posted by firemanbill

I ran it for over a year on 8s in my old shoestring and even after the crash it lives on in another plane of my sons.

I'm Just going by Scorpion's own recommendations, plus based on the kv rating you would be getting RPMs approaching 20,000 which is way too high for all but racing props and risks shedding a blade: http://www.apcprop.com/v/html/rpm_limits.html

[firemanbill]

The prop I was running was within limits and had no issues, nor did the motor.

[firemanbill]

Now the air frame... that was a different story... That is why I am not trying to make another Great Planes version go that fast.

[firemanbill]

Emotech arming switch installed tonight.