Benchmark Test of the Twin Engine Electric Mapping Planes - RC Groups
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Dec 28, 2017, 10:59 PM
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Benchmark Test of the Twin Engine Electric Mapping Planes


Hello everyone, my apologies in advance as this is my first post. I have been lurking around, not contributing for about a year, and it's time that I start to attempt to give back. I ask for your help and advice in this project, and I hope that I can give you valuable information in return.

I'm very interested in aerial mapping/surveying at an affordable cost. That basically means I'm researching the aircraft that can carry the most payload in the most efficient manner (subject to some constraints). There's a ton of information here about new releases, and it's great info. My goal is to test/verify it myself, and publish those results in a clean and accurate manner so that you can save yourself some time testing and tuning. I'd like to eliminate as many variables as possible and test the airframes on a level playing field. Ultimately I would like to sell the best setup as a ready-to-fly system to customers at a much lower cost than others are charging (look at the eBee for example).

The planes I want to test are twin-engine foam planes under $500. In my opinion, they are the easiest and safest to hand launch for the amount of payload they carry. I've read, but not verified, that they are more yaw stable than flying wings. There have been quite a few released recently, and I'd like to benchmark their performance. The ones I want to test are as follows:
  • MyTwinDream (MTD) - Benchmark
  • Skywalker EVE-2000
  • Believer
  • X-UAV Clouds
  • Skywalker Titan
  • MFD Nimbus (maybe)

The independent variables I'd like to test on each aircraft are as follows:
  • Payload/AUW
  • Motor/prop combos
  • Airspeeds
  • CG locations

The dependent variables that I want to discover:
  • Takeoff ability
  • Cruise efficiency
  • Stall and maximum level speed
  • Glide speeds (l/d ratios)
  • Stall characteristics
  • Roll rates
  • Load factors before accelerated stalls

I'll also publish/maybe model the internal fuselage dimensions so you can see if your particular camera fits. This will also be combined with other advice/observations from other threads into a detailed but concise, unbiased, and accurate report. I'd also post the pixhawk parameter files for you to use for your maiden flights. I'm not planning on a build log because that's already covered in detail on other threads.

I have experience building and testing the Skywalker EVE-2000, and it will be a benchmark for me. I had consistent 2-hour autonomous flights at 16 m/s on a 16Ah 6s li-po battery. I'm sure the performance could be better with many upgrades, but I was happy to not spend more than $600 on the setup.

Please let me know if you have any useful insight into this process, or if you have data or suggestions that I should be aware of. Thank you for all of the useful information that you've shared thus far, especially Pompecukor and Arxangel!
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Dec 30, 2017, 08:40 AM
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Suscribed and anxious for further details!!!
Dec 30, 2017, 07:37 PM
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blizzard1287's Avatar
Subbed for sure. Please include any mods to the airframe you think are necessary.
Jan 10, 2018, 06:02 PM
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I would be interested which of those airframes have enough room for mounting double servos? I mean back-up: for example splitting the elerons and using two independent servos (should one fail the other will add redundancy). Is there enough room to make another servo-cavity in the wing?
Another interesting questions: which of those could be suitable for a emergency parachute. I know it is mostly not necessary, but when there is need to fly over populated areas I would prefer to have it.
Thank you!
Jan 11, 2018, 02:13 PM
Registered User
Quote:
Originally Posted by mluha
I would be interested which of those airframes have enough room for mounting double servos? I mean back-up: for example splitting the elerons and using two independent servos (should one fail the other will add redundancy). Is there enough room to make another servo-cavity in the wing?
Another interesting questions: which of those could be suitable for a emergency parachute. I know it is mostly not necessary, but when there is need to fly over populated areas I would prefer to have it.
Thank you!
All of these airframes have enough room for mounting double servos. You just need to cut the foam out of the wings or tails to do it. The Believer and Titan rely on a single servo mounted on the fuselage for each tail flap. It makes them quickly removable, but also difficult to make redundant.

Your parachute question is interesting because the Believer, Titan, and XUAV Clouds all have dedicated parachute bays with a simple servo-release mechanism. I will not be testing parachute recovery, but my goal is to tell you the performance impact of carrying the additional weight.
Jan 12, 2018, 07:31 AM
Air Crash Expert
sawman's Avatar
Subscribed. Interesting project you're undertaking. Could take a while to collect that much data, especially when considering all the variables. Heck, just keeping all the test in close proximity, weather wise, could be a challenge.
I for one would appreciate such data. Thanks
Jan 12, 2018, 01:19 PM
Registered User

Status Update


Things are progressing along quite nicely. I received my 5th and final plane (the Believer) in yesterday, and I am looking forward to assembling it this weekend. The other planes are 90% glued and wired. This weekend I will make significant progress on finishing the airframes.

I'm looking at a 2-day testing window if possible, but right now the forecast is well below freezing - 10F (-12C) for the forseeable future. I've added a photo of last year's January weather for where I live. Unfortunately the density altitude will be near -1000 feet (-300 m) when I test, so the performance will well above average. Hopefully that also will mean that I will see a lot of different results. Hopefully I can tune the airframes and gather the data quickly.

I've developed an equipment list that will be the same on each plane.
  • Pixhawk 2.1
  • Here M8N GPS module
  • mRo Next-Gen MS5525 Airspeed Sensor
  • Multistar 6s 12,000 (preferred) or 10,000 or 16,000 mAh battery pack
  • Skywalker 2816-12 500kv motors (KDE 3510XF 475kv motors once tuning and stall-testing is done)
  • Hobbywing Platinum Pro 40A ESC's
  • Mauch 100A Current sensor and BEC
  • APC genuine 12x6E and EP props (to start - will change for tuning)
  • Hobbywing RPM sensor for Motor RPM
  • 16-gram HK digital coreless servo 1.4 kg*cm - .05 sec / 60deg
  • YEP 20A HV SBEC (using 6v output for servos)
  • 3DR 500mw SiK radio 900mhz
  • FrSky X8R 16ch receiver

I built my 3D printer yesterday, and after it is calibrated this weekend, I plan on designing and printing some quick-change mounts for the parts list above so that I can use the same equipment on each plane. That should give you even more consistent data.

There will be virtually no external modifications to the airframes. I don't have time, and I want to compare these planes in an unbiased way.
Last edited by naterater; Jan 30, 2018 at 02:23 PM. Reason: Update equipment list
Jan 14, 2018, 04:33 AM
Registered User
Very good post, any progress ?
Jan 14, 2018, 12:53 PM
Registered User
The airframes are 95% finished. Now the challenge is mounting the same electronics on each plane, setting the correct initial CG's, and finding good weather to test in.
Jan 20, 2018, 11:45 AM
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any personal advice like "I particulary like ****** model" are also welcome!
Jan 21, 2018, 03:04 PM
Registered User
The planes are assembled - now comes the electronics installation, tuning, and testing. Only the MTD has flown, and I'm waiting for consistent weather. I don't want to give you any misleading information, but to tell you the truth, I really like the Titan. It has by far the biggest fuselage, a removable bottom camera bay, and weighs the same as the EVE-2000 with the same wings. A lot of people like the EVE-2000, and the Titan is an improvement for mappers. When it comes to efficiency, the XUAV clouds looks like the sleekest design, but I'm pretty sure it won't fit a gimballed landscape camera. The believer is in-between. The MTD is very sleek, but too small for large li-ion batteries, and it won't fit a large landscape camera well at all.

The glued airframe weights and wing areas are included below. Based solely on wing area (tails not included), the Clouds might be able to carry the most. The efficiency results are not in, but progress is being made.
Jan 22, 2018, 01:08 AM
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Beerwiser's Avatar
Before you get carried away with the electronics I would love to see pictures of the component bays with something as reference. That seems to be the biggest disappointment is ease of access at least for me. Looking forward to your results
Jan 22, 2018, 02:29 AM
Gaftopher
Gary Mortimer's Avatar
@Beerwiser, me too and my fat fingers.
Jan 23, 2018, 04:11 AM
map addict
cioro's Avatar
I didn't found anywhere the distance from middle of the motor to the body of the Titan plane. It will be useful to know if you can fit a bigger prop than other airframes.
Jan 23, 2018, 03:41 PM
Registered User
Quote:
Originally Posted by cioro
I didn't found anywhere the distance from middle of the motor to the body of the Titan plane. It will be useful to know if you can fit a bigger prop than other airframes.
It'll swing a 16" APC prop. (8")

I'll be posting other photos soon to give you all a comparison.


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