2.4m DIY Twin boom for Aerial Photography, Video, GIS, Photogrammetry

Hi Forum, I am a fairly new user to APM2 (made about 4 successful flights on a skywalker.) And I am looking at building a twin boom aircraft for taking Aerial Pics to be used for GIS, land surveying etc.. I initially built an off the shelf twin boom called the URSUS, but due to its wooden spa construction, it broke in half in mid air. I have added glue, carbon and ply reinforcements, but now its too heavy to fly. Therefore I thought i'd try and build something myself using its power system

Here are my objectives

  • Must be able to accommodate a roll gimbal (I made this for the URSUS)
  • Must fly for 45 + mins
  • Must be shower/rain proof
  • Must Fit in the back of a Volvo V50!
  • Must be able to fly slow or fairly fast into wind
  • Airframe without power system should weight less than 1.5kg (based on weights taken from other airframes in this size range)

Based on some research, I have discovered that aircraft in the 2.2 - 2.6m range can achieve this. I have a moderate amount of building experience, using polystyrene, depron. But have never tried to build anything that performs well. 

I am going to make the Fuse out of fiberglass, and the wings out of EPP. 

Some technical details...

Wings 

  • Wingspan - 2200mm
  • Chord - 250mm (giving an aspect ratio of 1:8.8 )
  • Profile - Clark Y (noticed a lot of these aircraft use a clark-y profile)

Fuselage

  • box section - 120mm x 120mm x 600mm (excluding nose cone and tail cone)
  • Booms - 51cm, From trailing edge of wing to start of vertical fin

Power System

  • Esc - Castle Creations Phoenix 45
  • Motor - Ultrafly F/18/10 1000KV Brushless motor (model number uf-mtr-f1810)
  • Prop - 10 x 7
  • Lipo - 2 x 5000mah 3s 11.1v

Some pics... there will be a nice cowl on front and back of fuselage, but i cant do that with my limited CAD skills! 

This thread and idea is a product of realizing that the lower end off-the-shelf airframes are not capable of what I want to achieve. I have reached that conclusion in my Arial Photography thread here.. The Skywalker is great, but can't fit a roll gimbal in it (I keep getting pictures at different angles). The Ursus is nice, but the construction is too weak for my needs. Whilst working on a new airframe, I will be continuing to use the overweight ursus to perfect my roll gimbal. However a new airframe is needed to get longer flight times. I quite like the medium priced hugin, but thats a little out of my price range right now. 

I can get EPP wing cores cut for £40, and a fiberglass fuse made for next to nothing.

I have a few questions - 

  1. What distance should there be between the booms?
  2. What is the best aspect ratio?
  3. What thickness should the carbon booms be?
  4. What height should the rudders be?
  5. Is it best to go with an inverted V or H tail?

If anyone with aerodynamic knowledge has any fairly simple calculations to see if this will work, please could you let me know! or any other thoughts for that matter, positive or negative!

Cheers

 

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Please, let me know when you have the complete info about the plane!

Quick question. I'm having a few issues with the APM tests I am doing on the bench. As soon as I power the APM on, it is in manual mode, which is great, and i have full control over the surfaces. However after about 20 seconds, or around a minute, I lose all control between my 35mhz tx and the plane. however the servos are still working when i titl tthe plane on stabilize mode. 

Due to this issue, I am going to buy a new tx/rx for the test plane. I suspect it could be to do with signal issues, plus the Futaba 9c i am using has a faulty screen (a number of lines are missing).

I am considering going with a long range system, What long range systems and transmitters so people use for APM? Or do most people go with the Expensive Spektrum 7/8ch tx's?

Rich

Hi Rich.

Very pleased you got the plane going, well done. Good feeling init.

Cant help with advice re long range radio but that fault sounds odd. When it stops working does it change mode? Just wondering if you have set up all the modes. Perhaps one is just on the edge? Guess it was OK before the APM was in?

Have been busy designing a sexier looking fuselage to make a mould off.

 

It certainly was a good feeling to see it lift off with no drama! I decided to try and take a video off the issue today.. but after several attempts to replicate the issue, I could not for the life of me replicate it! typical! I reckon it'l raise it's ugly head mid flight on the weekend.

Do tell me more about the new fuse! - i've got a lot of the materials for the next build, its going to be a fiberglass fuse, and fiberglass wings as well, which should be easier to clean, i dont think you can get mud off epp foam!

I'm using Turnigy 9x with Scherrer UHF. It's an odd combination, I know - the cheapest radio with the most expensive long range system. The are cheaper alternatives to Scherrer UHF that probably work just as fine.

I'm considering getting a turnigy 9x. I would like to get a module for my futaba 9c, but the screen is faulty, so think it may be best to go with a new radio like the turnigy. I also need to find a uhf system that will work alongside the 433mhz 3drs - based in the Uk. And using 35mhz for control at the moment. Also considering 2.4ghz for control.

Cheers Martin, I've posted a question in the RC Electronics Forum - I'm torn between about 5 Transmitters, One of which is the Turnigy 9x. I wonder what the general consensus is..

Just in case anyone is interested, but i've started a new thread in the Aircraft platforms forum to do with using flying wings for Aerial photography. I'm going to persue this avenue for now. And plan the new twin boom design in the new year...

Rich

Just made a catapult launcher for the flying wings - I wonder if I could modify it to launch this!!! 

Richard, looks good but you need a fair bit of power to launch the heavier plane. Awhile ago now I made a launcher that works quite well using a pulley system and a compressed air ram, if you want some details let me know and also have a look at YouTube, search diydrones launcher.

Regards richie

Cheers for the info, I only put the plane on there as a bit of fun to see what it would look like... the launcher is designed to use bungees, and will only really launch planes up to ~2.5kg. the plane above is around 4.5kg if i remember rightly, and you need about 5g to launch off a catapult. So i'd need about 25kg of power! 

Probably not going to get that out of bungees!

Just looked at the video, I'm guessing it was this one... mighty impressive! 

Richard, I have also uploaded some pictures of the launcher details and will add some more after easter as I will be using it then and will also try to get some more video of it in action.

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