Thread Tools
Jul 08, 2019, 09:20 AM
igi
igi
Easy Glider
Thread OP
Gallery

little indoor VTOL


I just thought someone might be interested in this little scratch built VTOL plane I came up with for our weekly flying in the local gym. It is made of Depron sheet material and uses 7mm brushed motors, a 1s 400mA battery and a micro F3 Flightcontroler. AUW is 27grams, wingspan 34cm. Although basically a converted quadcopter , there is a lot of lift from the wings in forward flight, so you can throttle back quite a bit to a point where the 2 front propellers nearly stop. Good thing is, you can do the transition progressively and thus do slow forward landings and take offs as can be seen in the video. Altogether much flying fun from little effort.
cheers
Ingo

VTOL 2 (3 min 15 sec)
Sign up now
to remove ads between posts
Jul 08, 2019, 12:36 PM
Registered User
Ran D. St. Clair's Avatar
Very Nice!
Jul 08, 2019, 01:03 PM
Registered User
Flies great. Smooth!
Jul 08, 2019, 07:17 PM
Registered User
Looks really nice. Do the rear rotors tilt in forward flight?
Couldn't quite make out from the video.

If you have more information on the build that would be interesting to see.
Jul 09, 2019, 12:51 AM
Registered User
britinoz's Avatar
Yes... Very nice...
Jul 09, 2019, 03:51 AM
igi
igi
Easy Glider
Thread OP
Quote:
Originally Posted by nausher
Looks really nice. Do the rear rotors tilt in forward flight?
Couldn't quite make out from the video.

If you have more information on the build that would be interesting to see.
The rear rotors have a constant forward angle of 45 in relation to the wing, the front rotors are 5. I will write up some details about the built and ad photos if there is an interest.
Ingo
Jul 09, 2019, 08:08 AM
Registered User
Bring on the photos and details. Great project!
Jul 09, 2019, 01:06 PM
igi
igi
Easy Glider
Thread OP
Quote:
Originally Posted by Tcat
Bring on the photos and details. Great project!
Well first of all I have to give credit to the developers of the Inductrix Switch Air from Horizon which inspired me to start this project. Starting from their design I made quite a few test builds with various wing shapes, motors etc. which taught me that things are not as easy as they might look. Finally I hit success with a smaller and bigger version of a VTOL flying wing following their primary idea. https://www.rcgroups.com/forums/show...8380%29/page37. (see posts 550 and 564) Going on from there I added a fuselage to the flying wing and did some further fine tuning of the flightcontroler and wing shape... What I found is that it's all about the right balance between rotor angles, their position in the wing and the shape on the wing. It is surprising what huge effect small alterations of these variables create. Of course the weight / power balance is something to take account of too. I attach some photos that should be self-explanatory. Feel free to ask if you need any further information.

Ingo
Last edited by igi; Jul 09, 2019 at 01:42 PM.
Jul 09, 2019, 05:35 PM
Registered User
Ran D. St. Clair's Avatar
Quote:
Originally Posted by igi
Well first of all I have to give credit to the developers of the Inductrix Switch Air from Horizon which inspired me to start this project. Starting from their design I made quite a few test builds with various wing shapes, motors etc. which taught me that things are not as easy as they might look. Finally I hit success with a smaller and bigger version of a VTOL flying wing following their primary idea. https://www.rcgroups.com/forums/show...8380%29/page37. (see posts 550 and 564) Going on from there I added a fuselage to the flying wing and did some further fine tuning of the flightcontroler and wing shape... What I found is that it's all about the right balance between rotor angles, their position in the wing and the shape on the wing. It is surprising what huge effect small alterations of these variables create. Of course the weight / power balance is something to take account of too. I attach some photos that should be self-explanatory. Feel free to ask if you need any further information.

Ingo

Very nicely done. I can see the subtle details that make it work so well.
Jul 09, 2019, 07:00 PM
Registered User
Many thanks for prompt reply. CG looks to be at trailing edge of front props? Am reading up on F3 flight controllers. Appreciate details of build.
Jul 10, 2019, 04:59 AM
igi
igi
Easy Glider
Thread OP
Quote:
Originally Posted by Tcat
Many thanks for prompt reply. CG looks to be at trailing edge of front props? Am reading up on F3 flight controllers. Appreciate details of build.
nope, CG is exactly where the flight controller sits. You have to keep in mind that this bird is more of a multicopter than an airplane. In order to obtain a hands off hover the CG has to be right in the center between the 4 props. In forward flight mode the rear props turn faster then the front ones which leads to a forward tilt of the plane. If the rear props were not mounted at an angle this tilt would lead to a negative angle of attack of the wings... the aim is to achieve just the right slightly positive incidence of the wing in forward flight that creates enough lift so that the front props nearly stop . Too much lift ( too much positive incidence) makes the whole bird unstable as the flight controller can no longer fullfil its task. In order to stop the wing from rising it can do no more than reduce the speed of the front props until they finally stop, if the lift still continues the plane will flip over. This happens most likely at higher forward speeds or sharp turns and is one of the reasons why the adjustment of this thing is quite challenging..... This plane will never glide as it loses all control when the motors stop, so the placing of the CG does not have to follow the rule of a "real" airplane.... oups, got a bit carried away..

Ingo
Jul 10, 2019, 09:25 AM
igi
igi
Easy Glider
Thread OP
@ Tcat

Sorry I reread your post and you are completey right about the CG . It is indeed at the trailing edge of the front prop circle. I did confuse it with the leading edge. So I could have spared me the long sermon that I wrote up...
Jul 10, 2019, 03:59 PM
Registered User
The sermon was informative, thanks.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Nice little 2 blade indoor model Jockadopolus Auto Gyros 2 Feb 20, 2017 02:33 PM
Question Working on a Wingnetic VTOL and need a little help BGauweiler VTOLs 5 Dec 19, 2016 09:39 PM
Indoor VTOL ornitech Scratchbuilt Indoor and Micro Models 21 Jan 11, 2004 09:26 AM
Micro Indoor VTOL av8rx Micro Helis 1 Aug 24, 2003 10:42 AM
vtol indoors urs Scratchbuilt Indoor and Micro Models 4 Dec 16, 2002 04:56 PM