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Feb 21, 2018, 11:55 AM
ARACE UAS
Pompecukor's Avatar
Quote:
Originally Posted by mike_o
But it may have been the non-critical motor
Yes, I never verified that.
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Feb 22, 2018, 11:30 AM
Registered User
Thread OP

Status Update & Unfortunate Delays


Hello everyone, thank you for the continued discussion. I will continue to use matched-pairs of APC props for this test because the selection of diameters and pitches are large. Based on APC prop data, with large, high pitch props, the torque value may be substantial. EX: a 14x14 prop (should be one of the most efficient at cruise - 85%) takes about 1.3 kg*cm (1.5 in*lb) of torque per engine at cruise. Think about moving 1000 grams of your payload about 3cm to the right. It's not bad; HOWEVER, when you are talking about max takeoff power and torque, it may be significant. The 14x14 prop takes about 10 times the torque - 13 kg*cm at hand launch speeds and full ESC capacity (40amps, 6s). That's a lot of torque, and if both motors were turning, it would take 3000 grams (your entire payload) moved over about 8cm to balance the load on the airfoils. Don't get me wrong, with small pitch and diameter props, the torque is not significant. If you want to get very efficient propellers, I believe the torque will be significant.

On to my most recent testing - the TITAN:

BAD news - I've had three crashes - mostly user error.
#1: Attempted a launch with a significant crosswind probably about 7m/s (13mph). The wind basically pushed it into the ground about 3m away from the launch point. Broke the payload bay mounts on the fuselage, the props and my motor mounts. Root cause: user error of not launching into headwind

#2: One of the V-Tail sections fell off about 60 seconds after takeoff. I had done two or three gentle turns, and the air was incredible smooth. When I started the next turn, the tail blew off and the aircraft pitched and spun uncontrollably. It entered a semi-stable descent spiral and crashed belly-first. This cracked the tail off of the frame and broke, all else appeared fine. Root cause - VERY poor tail "latch" design. I may go into this into more detail about this in a later post, but I should've corrected this with some tape over the connection. It's a push-snap-in design, and it's too easy to remove.

#3: Wing delamination on takeoff causing the worst crash. I hand launched into the wind, and the aircraft almost hit the ground before continuing its automatic climb. After grabbing my transmitter, I looked at the wings in a slight U-shape but continuing to climb. The switch from auto mode to FBWA (flying level) caused enough of a jerk to completely separate the left wing. The result was a spectacular warlike bomber spiral dive into the ground causing catastrophic damage. Root cause - BSI Foam Cure glue AND a poor wing structure design. The carbon-fiber spars put all of the load onto the lower panel of the wing. Goop is the glue to use on this foam, and I will never go back. Even the tube glue that comes with the kit is better than the Foam Cure. I'm sure that crash #2 damaged the wing, and I didn't notice the problem on pre-flight inspection.

I was very hopeful about the Titan, but the unreliable/poor design is really weighing on my decision to continue testing it. No other airframe in the test has the same design issues (except the EVE because it uses the same wing). The risks can be mitigated, but I'm disappointed to say the least. On a positive note, the flight controller and most of the internals are safe.

AIRWORTHINESS SAFETY NOTICE on SKYWALKER TITAN: secure your pop-in tail, and make sure your wing panel gluing is adequate.
Feb 22, 2018, 11:49 AM
ARACE UAS
Pompecukor's Avatar
Woops, I had a bad feeling about the Titan, just because it was made by Skywalker. My confidence in them making "good" frame was shatter completely when they release the Eve and Wall-E. There was such fundamental design flaws (only enforced by the market "failure" of both UAVs) in them that I decided I will never spend money with a company that is ready to release such garbage to the market. These flaws were obvious from simply looking at the pictures. Way before anyone actually order one.
Yes, they did have some successful platforms in the past (the original "Skywalker"), but that was a long time ago.
It amazes me that companies like Skywalker and XUAV, with big/established name on the market can mess up so badly.

Then "nonames" pop up from no where all of a sudden and get it right the first time. aka MTD and Believer.
(And yes, I know MFD was a big brand even before the MTD, but was not know for any air-frame, just electronics. Also yes, Nimbus is a failure, but I think it has a lot to do with Charles personality and the "money craze" that happens when you suddenly become "too" successful.

Sorry to hear about all your misfortunes nat. Happy to see that you still have a positive attitude.
Latest blog entry: longrangeFPV.com
Old Feb 22, 2018, 03:57 PM
dlgmad
A moderator felt this post violated the following rule: Trolling (Provocation). It is temporarily hidden while dlgmad edits it.
Feb 22, 2018, 05:40 PM
ARACE UAS
Pompecukor's Avatar
Quote:
Originally Posted by dlgmad

Pompe just hi jacking another thread with nothing to add but BS. ........ Go and show us all a proper long range flight with the video feed the hole flight .....

Garth.
I am not sure about why all the static, hate and getting personal? I am almost sure you have no relations to the company Skywalker whom I spoke about just now.
I believe my opinion about the units is well founded. Please look around and you will see that both units can be qualified as failures.
It even took over 6 months after it went on sale, for the first video of the WALL E2000 to surface. The Believer has had more post and traction in 3 months than both the Skywalkers put together in the last 9 months. You think that is a coincidence? I am almost sure more people already have Believers than those who have E2000.

With regards to you calling "everything" that I have written in this topic "BS" really shows that there is some serious obsession going on. You don't even try to hide it with citing my long range flights. It is the second time it has been randomly brought up in a completely unrelated topic in the same month, first by your flying buddy, now by you. And my last attempt was over 2 years ago. Why don't you write a long email/PM to me about how you really feel. Why put it on all these nice people?

To quote someone you know, for some good advice...

Quote:
Originally Posted by dlgmad
Time to get back on topic...... ahhhh
Garth
I am not going to lash back at you. Let us all be friends and have fun.
Last edited by Pompecukor; Feb 24, 2018 at 07:42 PM.
Feb 22, 2018, 11:28 PM
Registered User
Beerwiser's Avatar
Nice video Pompecukor
Feb 23, 2018, 01:20 AM
ARACE UAS
Pompecukor's Avatar
Thank you sir.
Latest blog entry: longrangeFPV.com
Feb 23, 2018, 02:47 AM
Registered User
Beerwiser's Avatar
So as a farmer, are the yellow fields mustard or canola? Have to ask, its in my nature lol.
Feb 23, 2018, 03:24 AM
ARACE UAS
Pompecukor's Avatar
Sunflower
We grow a lot of it.
99% used to make vegetable (sunflower) cooking oil.
Latest blog entry: longrangeFPV.com
Feb 23, 2018, 04:54 AM
Registered User
Beerwiser's Avatar
Now that deserves a nice high def low pass, I have never seen sunflower as a crop. Just in the garden. PM me if you have a clip of that, I don't want to derail Naterater's fine work.
Feb 23, 2018, 06:14 AM
ARACE UAS
Pompecukor's Avatar
Hi. Check out the entire channel. There might be something there that you like. I will also send you my older channels link which also has lot of videos.
And yes, let us contuniue in PM. Thank you.
Latest blog entry: longrangeFPV.com
Feb 23, 2018, 12:11 PM
Registered User
I think I have to agree with what's being said about the Titan. I ordered it because we have a need for lots of cargo space, and the Titan does well at this. However, the general fit and quality of the model isn't very good. Compared to the MyTwinDream and the RMRC anaconda, the quality of the Titan is really poor.

The packaging also isn't adequate to get the model here without breaking. I received mine and the box had little to no damage and the tail of the fuselage was nearly snapped off. The foam was super compressed so it made it difficult to straighten it out. I had to soak it in hot water for 40 minutes to get it straight again. Now I have to epoxy it back together which is just adding unnecessary weight to the tail.

Also, the build guide is terrible. And I don't know why they recommend 9 gram servos for this model, but I certainly would put something bigger in than that. As I'm building, I may put together my own build guide and share it with the community unless naterater beats me to it.

Maybe my opinion of this aircraft will change once I get it up in the air, but for now I think the next one I'll order is a believer.
Feb 23, 2018, 01:27 PM
Registered User
It is shame for Skywalker to have so great design as Titan, but so poor quality. I also had a big expectation about this plane but I think many followers of this thread will choose another platform.
Feb 23, 2018, 01:58 PM
Registered User
Thread OP
I politely request that the discussion stays mostly on the topic of aircraft performance and testing. If you would like to go into detail about these airframes, please do it on the discussion threads for the aircraft, not here. Although there are some quality issues that affected the titan in my testing, I believe that ALL of these issues can be individually addressed without too much effort. The test will continue with it, and the results will be evaluated once the data is collected.

Sorry for leading the thread down this wormhole that has caused a lot of clutter posts. Here are some pages for your reference.
Mar 01, 2018, 12:58 AM
Which one is aileron again?
I wonder how many reading this thread work in university labs. I'll give everyone one guess as to where I work.

Thank you for all your hard work so far, Naterater.

I'm rooting for the Believer for a few reasons but none of them are based on hands on experience with any of these aircraft.

For what it's worth, I highly recommend looking at the Sony RX0 if you want a fast and light weight imaging camera. I'm hoping to get a second and fly with two to see what can be done with them in Photoscan. Also, don't use the mechanical shutter. They're really not designed for the kind of abuse they will receive on a mapping aircraft.

If you're looking for some amazing servos and have a huge budget, check out the Ditex micro. Otherwise, I haven't really found a servo to bridge the gap between say a Corona $5 digital and something like a $50 Futaba s3156mg.
Last edited by prototype3a; Mar 01, 2018 at 01:04 AM.


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