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Feb 03, 2015, 03:07 AM
3D madness
Almasy's Avatar
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Build Log

Savage Cruiser 80" by Seagull Model


Hi everyone
I just started this project. Got this from jb-hobbies.com for a very reasonable price.




Specs:
Wingspan: 79.9" (2030mm)
Wing area: 1001.3in2 (64.6dm2)
Length: 58.8" (1493mm)
Flying weight: 9.7 - 10.6lbs (4.4 -4.8Kg)
Radio: 6-channel, 6-8 servos
Glow: 2-Stroke .91 - 1.25 cu. in. 4-stroke .91 cu. in.


Everything inside the box. First impression: the cover quality is very nice. Fiberglass cowling and wheel pants are very smooth and shine.

Problems found: wing tube too tight. Have to attach the wings very carefully. It seems better after attach and remove several times
Last edited by Almasy; Feb 08, 2015 at 02:02 AM.
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Feb 03, 2015, 03:25 AM
3D madness
Almasy's Avatar
Thread OP
This plane is very easy to build. Epoxy is required just for elevator, rudder and control horns. Control surfaces use CA hingles.

Landing gear is a little bit heavy, but very strong.

problem found: the servo control linkages are too long. I replaced with some classic style V-bend linkages. No choice ATM.
SERIOUS PROBLEM FOUND: Detach the battery tray in two pieces and re-glue it with epoxy. This tray is poorly glued and very easy to pop out, very high risk of the battery will fall off when doing high G maneuvers.
Last edited by Almasy; Feb 08, 2015 at 02:18 AM.
Feb 03, 2015, 03:26 AM
3D madness
Almasy's Avatar
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Finish build, pre-maiden flight test and setup

Here is my setup:

Motor: Dualsky XM5060EA-6 470Kv (1849w)
  • 49mm Diameter x 58mm Length
  • For aircraft up to 5.1kg / 11.25lbs
  • 1849 Watts burst power
  • 6 cell setup
Propeller: 16x8 APC
ESC: Castle Talon 90A with built-in 20A BEC, 6 volt.

-First run with no load, the motor draws 3.1 amp
-Second run with 15x8 Turnigy wooden prop. 76.7 Amp recorded (~1700w). This prop has very poor efficiency. I think with it would draws about 70A (1500w) with a same size APC prop.
-Last run with 16x8 APC prop. 81 Amp recorded. Approx 1800w. So this is the perfect prop for this motor size and ESC.

This power setup seems a little bit under power, right? This is what I thought. But not! Check my fly preview below!

Plane setup:
<update later>
Last edited by Almasy; Feb 08, 2015 at 03:17 AM.
Feb 03, 2015, 03:26 AM
3D madness
Almasy's Avatar
Thread OP
Flying characteristic report, flight video, summary..

First day

Did maiden flight today. With the 6S 1800w setup, I thought it would be under power but I was wrong. I couldn't believe when it took off just after very short run Cruising at about 40% throttle stick, I did not even go full throttle all the time! This power setup is perfect for your budget, period.

I used 6S 7000mah battery (2x 3500 parallel). After 7 minutes cruising, couple loops and hammerheads, one touch and go, 300 feet taxi run. Believe it or not, battery remains at 23.8v I would have 15 minutes flight easily with this batteries But I'd rather remove one battery because the plane is nose heavy pretty much. 4000-5000 mah is enough. This plane doesn't mean for speed, it flies AMAZING at crusing speed

About flying characteristic, I recommend to setup your aileron throw as much as you can. The plane responses very slow on roll axis because of low CG, also because this plane flies at slow speed most of the time. Trust me, you don't wanna go fast with this beauty you fly it slow and you will see how beautiful it is in the air

Elevator/pith axis is very smooth and very easy to do a perfect loop. Rudder is much responsive, it does hammerhead maneuvers very nice. Again, VERY NICE! I did not try other maneuvers yet.

Maiden flight was successful. I'm VERY VERY happy with the plane's flying characteristic. It does perfect loop, perfect hammerhead, and almost perfect landing!

I did not doing much for the maiden flight. Next time I will report flying characteristic on other maneuvers, include spin, knife edge and other information on landing/take off/flaps...


Second day
Did couple flights and got some result:

With 6s 4000mah battery:
- Full aerobatic flight
- Flight time: 6 min 30 sec
- Battery: lowest drop is 19.8v during flight. Remain at 22.3v after flight.
- ESC Temperature: min 82F, max 102F (28C-39C)
- BEC voltage: Min 5.6v max 5.8v. Very awesome BEC. handle 7 standard servos total.




With 6s 3500mah battery:
- Full HARD aerobatic flight
- Flight time: 5 min 40 sec
- Battery: lowest drop is 20v during flight. Remain at 22.3v after flight.
- ESC Temperature: min 86F, max 105F (30C-40.5C)
- BEC voltage: Min 4.9v max 5.8v. Serious volt drop because of multiply flat-spin. Still acceptable.




I'm happy with 3500mah battery now Much lighter than my maiden flight with 7000mah

- Loop: this plane does very good loop, slow and nice. Inside loop only. Outside loop is dangerous, should not do it.

- Roll is a little bit slow, I recommend to go a little high speed, nose up about 30 degree then roll. Should not do double roll in a row. If you still want to do, make sure your flight path is long enough and must use elevator to control the plane's attitude.

- Hammerhead is nice and neat.

- Invert flight is unstable and require a lot of elevator pull.

- Snap-roll (outside): nice but dangerous, risk of stall and requires a well-experienced pilot. For LEFT Outside Snaproll: Climb your plane high, pull 45 degree up and push full LEFT rudder, full elevator DOWN, full aileron LEFT. Full throttle. Maneuver ends with the elevator stick keeps pull down while aileron and rudder neutral until the plane stoll rolling and dive to regain speed. Maximum is 720 degree roll (two turns in a row), the plane reduces speed very quicky, more than 720 degree is a big no-no. You can try to do right side roll by use right rudder and right aileron instead.

- Snap-roll (inside): I don't recall that I did it or not. Basically same maneuver but use full elevator Up instead.

- Curban 8 is SWEET. Inside loop only.

- No knife edge maneuver.

- Spin and Flatspin: AWESOME Climb as high as you can, slow your plane until it stall, full LEFT rudder first to kick your plane completely stall, full UP elevator, FULL THROTLE and it spin like crazy Input FULL RIGHT Aileron for almost-flat spin and even crazier spin rate
But NEVER-EVER go too low. Recover after spin is NOT easy. If you cut throttle and neutral all sticks, the plane keeps spinning for about 720-1080 degree and completely UNABLE to control. When it stop spinning, keep dive down with some throttle to regain speed.
If you want quick recover, pull your rudder to the right, you may able to stop the spin just within 180-360 degree. Dive down and regain speed.
Flat-spin is not recommended if you don't have a good BEC. Critical volt-drop because 5 servos must work hard. You can see how the volt drops above.


Take off and landing:
- 1/3 to half flaps is perfect for take off. The plane will takes off by it self at a very nice angle. Very cool looking.
-Landing is a little bit tricky. With full flaps extended will slow your plane very very much. Don't use flap in windy condition, it's unstable. If you want to do two-point landing without touching the tailwheel to the ground, go with a little speed, slowly touch your front wheel and keep running on the runway. It is neither easy nor hard, but when you get the idea how to land, it will be awesome.
Summary:
<update later>
Last edited by Almasy; Feb 11, 2015 at 10:20 PM.
Feb 11, 2015, 08:21 AM
Registered User
missle's Avatar
Awesome job with the build and flight report. She looks really cool especially with your pilot. I guess the only thing you could do better is get a vid

On a different note, that voltage sag is concerning to me as I've become a huge Talon fan (currently using a couple of the 90's and HV120's) of which all my birds have full size Savox servos which love to suck electricity. Now I'm going to have to try the telemetry function to see whats happening. I think I can do it with the DX9 correct?
Feb 11, 2015, 11:27 PM
3D madness
Almasy's Avatar
Thread OP
Quote:
Originally Posted by missle View Post
Awesome job with the build and flight report. She looks really cool especially with your pilot. I guess the only thing you could do better is get a vid

On a different note, that voltage sag is concerning to me as I've become a huge Talon fan (currently using a couple of the 90's and HV120's) of which all my birds have full size Savox servos which love to suck electricity. Now I'm going to have to try the telemetry function to see whats happening. I think I can do it with the DX9 correct?
Yes DX9 should be fine. With basic spektrum telemetry , you will be able to monitor the ESC temp (wrap sensor around it), Battery's voltage (must do some soldering) and Receiver's voltage.

I will upload video this weekend. This bird has many nice spot to mount a GoPro.
Feb 17, 2015, 12:45 PM
AMA 34191
Vulgar Vulture's Avatar
Interesting report on a plane I've never even heard of! Looking forward to the flight video!
Feb 26, 2015, 08:49 AM
3D madness
Almasy's Avatar
Thread OP
video here

Savage Cruiser 80" by Seagull Model (2 min 22 sec)
Feb 27, 2015, 07:08 PM
Registered User
missle's Avatar
Now that was nice! Definitely looks like you have tons of power for her and tons of throw for such long control surfaces. I like it!
Mar 07, 2015, 09:11 PM
Registered User
brockettman's Avatar
Nice work on the video! Thanks for posting the build experience too. I've decided to start working on my Cruiser and have enlisted a little help... Hope you don't mind me posting a couple of pictures as the one I'm building won't be electric
Last edited by brockettman; Mar 07, 2015 at 09:15 PM. Reason: clarification
Mar 16, 2015, 07:26 AM
Registered User
bigmoebbq's Avatar
Just picked one of these up. Hope to maiden in the next few weeks. Mine is electric.

Any tips?
Mar 24, 2015, 12:02 PM
3D madness
Almasy's Avatar
Thread OP
Quote:
Originally Posted by bigmoebbq View Post
Just picked one of these up. Hope to maiden in the next few weeks. Mine is electric.

Any tips?
The plane is very easy to take off and land. I recommend to so set your aileron throw as much as you can. Plane responses kinda slow on roll axis, especially at low speed.

When install motor mount, adjust the motor angle about 5 degree down. Or it will automatically climb when you push your throttle. You better make it adjustable so you can adjust it later.

Beside, remember to re-glue all important parts:

- Battery tray. As I said in previous post.
- Servo mount plate: I got it pop out, not in flight but during transport. Just reinforce with epoxy.
- The plastic screw nut insdide the main wings. This one easy to pop out, it doesn't harm your plane, but just annoying.
- Keep in mind that you should re-glue everything that pre-glued.
- Plane is nose heavy. Keep everything in the back if possible. It does fly very good with nose heavy though, but you will see the elevator trim is at very high angle.
Mar 24, 2015, 05:52 PM
Registered User
bigmoebbq's Avatar
Awesome thanks. This one is going to use a 5000mah 6s battery. It has ridiculous power! I will double check all the joints. Thanks for the heads up!
Mar 25, 2015, 12:43 PM
Registered User
corsaircrazy's Avatar
Have one coming from Sig... anyone know the spinner diameter?


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