Steve Adams Posted December 27, 2016 Share Posted December 27, 2016 Hi Tony, I'm no expert at all! But how about fitting inside the Harrier some small robust helium filled balloons so you can have some just above ground buoyancy then let the propulsion from the swivel fans do the rest? This would hopefully mean that you could use lower powered fans and lighter batteries etc. There is no guarantee of it working,but would be a fun debunking experiment nonetheless! Looks superb anyway though! Kindest Regards Steve Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted December 28, 2016 Author Share Posted December 28, 2016 Great for indoor .....a blimp harrier....similar to the helium filled airliner that's been kicking around youtube Quote Link to comment Share on other sites More sharing options...
onetenor Posted December 28, 2016 Share Posted December 28, 2016 Speak to Andy Sephton on Aeromodeller Forum/Live chat about flying the real thing and the transition just from standing and transitioning to the hover Not simple from what he told me Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted December 28, 2016 Share Posted December 28, 2016 The balloons would be a waste of effort on a model of this type. The mass of air is approximately 1.2g/l. For helium it is 0.16g/l. This gives helium a "lifting power" of about 1g/l, so even if you could fit 10l of helium in the airframe you would get less than half an ounce of lift. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted December 28, 2016 Author Share Posted December 28, 2016 Ok so one of the reasons why the Harrier hover to transitional flight will be achievable in some form or another is down to a guy called Mike Sayer who has assisted me with an alternative Harrier design and control..... this spin off is on going and a smaller version Harrier is being built using Mike's avionics installed...... Here's Mikes VTOL machine and remembering this machine only uses single directional fans so gimbling fans control the torque and yaw.....it is an incredible achievement **LINK** Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 28, 2016 Share Posted December 28, 2016 Incredible effort. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted January 21, 2017 Author Share Posted January 21, 2017 finally got some video of the mode hovering today Edited By Tony Nijhuis on 21/01/2017 17:05:58 Quote Link to comment Share on other sites More sharing options...
Alan Hilton Posted January 21, 2017 Share Posted January 21, 2017 It must have been frezing at middle bridge today . Looking good on hover now is it the same set up as the successful flight? Alan Quote Link to comment Share on other sites More sharing options...
Ian Newton Posted January 21, 2017 Share Posted January 21, 2017 Great to see it flying Tony. When are you going to attempt a transition? Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted January 21, 2017 Author Share Posted January 21, 2017 Yes it was freezing and the usual cross wind so.....The plan was to transition today but the wind was across the strip and try to hold the Harrier cross will is almost impossible....... unfortunately after this video was taken I had a bit of mishap....was fly around in normal mode (rog launch off a dolly) when I must have slowed it up too much in the turn and she rolled in....... so on to the Mk4 version I guess...what a journey Quote Link to comment Share on other sites More sharing options...
Ian Newton Posted January 21, 2017 Share Posted January 21, 2017 Oh no! That's such a shame. Still at least you have learnt a lot and each step brings you closer to success Quote Link to comment Share on other sites More sharing options...
bouncebounce crunch Posted January 22, 2017 Share Posted January 22, 2017 Yes, that is a shame. This aeromodelling is far from my skills and knowledge, it is more toward NASA x British aerospace to me. I hope you beat the challenge Tony. bbc Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted January 22, 2017 Author Share Posted January 22, 2017 Thanks guys.....fortunately the wings survived and new fus is almost finished....Its too close to stop now..... Quote Link to comment Share on other sites More sharing options...
John Holdsworth 1 Posted February 8, 2017 Share Posted February 8, 2017 OpenAeroVtol? Just a suggestion since its been designed for this kind of thing and combines gyros/accelerometers etc into a relatively easy to configure package..based on the kk2.1 boards which are widely available and cheap. In any event.... good luck Quote Link to comment Share on other sites More sharing options...
bert baker Posted February 8, 2017 Share Posted February 8, 2017 In thrust we trust Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted February 8, 2017 Author Share Posted February 8, 2017 There will five monthly articles starting next month (April issue) about trials and tribulation to date...so 10,000 words of explanation!!! just waiting for some better weather before venturing to the flying field again Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted February 8, 2017 Share Posted February 8, 2017 That's great. Looking forward to read your monthly articles and gain some insight. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted February 9, 2017 Share Posted February 9, 2017 I expect that you have looked at this already, but I have been watching some YouTube videos on the E-Flite Convergence. There is a lot of stuff on home brewed VTOLs too. Quote Link to comment Share on other sites More sharing options...
adam gordon-duff Posted February 15, 2017 Share Posted February 15, 2017 Hello everyone. Just a thought but would say 4 x 6" props give you better efficiency through static thrust? After all most quadcopters are prop powered? It's a large model so maybe even bigger props could be accommodated whilst still respecting scale appearances? Be gentle with the explaination of why not as I'm sure I'm missing something with this simple thought?!....All the best, Adam Quote Link to comment Share on other sites More sharing options...
Steve Cheyne Posted February 20, 2017 Share Posted February 20, 2017 Tony, I have just been made aware of your efforts by a friend of mine, looks like we have been working in parallel using the same design though mine is smaller using 4s and 50mm fans made from depron. I used a "flying bedstead" to derive the available thrust, control laws and vectoring system and my winged version is just being painted before first fligh. Currently the model weighs 1.5kg and I have 2.7 kg of (uninstalled ) thrust. Unfortunately it is my first time on this site and I am having trouble attaching photos, if you are interested I will email them directly, meanwhile I will try and find a young person to help me! Quote Link to comment Share on other sites More sharing options...
John Lee Posted March 28, 2017 Share Posted March 28, 2017 Tony In the April edition of the RCM&E you state that you are looking to transition with the fans in 3 positions 90, 45, 0 degrees. John Farley in his excellent book 'A view from the hover' states that for the pilot training for the transition of the full size Harrier they use an initial nozzle position of 15 degrees aft from a steady hover. To quote 'while such a change loses you only about 3% of your engine lift (or gives a 0.03g sink if you prefer)' it provides a very smart forward acceleration of some 0.25g. Pure piloting magic! That is why Harriers are able to leap forward from the hover without any obvious sink. That 3% vertical loss represents about 1% on the rpm gauge so, if you add a touch of throttle before you move the nozzle, the rush of lift from the wing as the IAS increases will soon have you up & away. I bet you never realised that Sine/Cosine relationship could be so useful!' In contrast a 45 degrees nozzle angle will lose you 30% of the lift. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted March 31, 2017 Author Share Posted March 31, 2017 Thanks John, That's interesting and make good sense...... Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 29, 2017 Author Share Posted May 29, 2017 Well its been some time since i last posted and hopefully the articles in the RCM&E were of interest..... Needless to say i thought by the time I had done the four articles, i may have some good news for you but this project is still very much on going and sometimes i think I'm just treading water. The hover is now very much sorted but (quadcopter) yaw control is poor and with any small amount of wind, the harrier will happily weather cock like a weather vane..... However today was the transition day down the Hastings club field and the harrier moved into into stage 1 forward flight with the fans switched from vertical to 20deg forward angle...interestingly, model did not accelerate is fast as i thought it would and didn't reach what i thought was a forward speed sufficient to go stage 2 (fans full forward 90deg). So i increased the stage 1 rotation to 40deg..... this time the harrier accelerated from hover nicely and kept straight and level as she moved away (still in quadcopter mode) then switched to stage 2 hoping she would power away in normal acro mode but instead she reared up vertically, flicked on her back ....at this point I thought that was the end so I hit the switch to return it to hover and incredibly she self righted an I hovered her to ground.....if i hadn't of done that, there is no way it would have survived. Not quite sure why the model reared up but may be down to the fan thrust line still being at an angle when the when all 4 fans then go to the same speed and this kicked the model up. As the fans are under the wing, the thrust, even when the fans are horizontal, will cause the nose to rise. Notwithstanding this....a positive day I think!!!! Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 29, 2017 Author Share Posted May 29, 2017 i suppose being an engineer, i alway like to have a backup plan so this is the latest design which now overcomes the yaw problem. Model has now test flown in hover and work great.....it uses a nano Wii board instead of a KK2 quadcopter board. The difference is that fans are pivot controlled independently by a servo so yaw is now done with gimbling the fans, backward on one side and forwards on another. The result is the model now yaws with authority and better still, i don't need contra-rotating fans .....they all rotate in one direction and the yaw control deals with the torque effect. the test model is purely a hovering test bed and the model AUW is just over 1kg..... Edited By Tony Nijhuis on 29/05/2017 21:38:40 Edited By Tony Nijhuis on 29/05/2017 21:39:23 Quote Link to comment Share on other sites More sharing options...
Guvnor Posted May 29, 2017 Share Posted May 29, 2017 Has anyone seen this one...? https://www.facebook.com/f35model Edited By Guvnor on 29/05/2017 22:41:32 Quote Link to comment Share on other sites More sharing options...
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