Ernie Posted May 31, 2017 Share Posted May 31, 2017 Many many years ago, i took my wee daughter to an airshow (leuchars perhaps) That plane I said, pointing to the harrier is going to stop in mid air Dont be so stupid was the reply, as 10 year olds do. So we got to the front of the crowd, right at the middle of the flightline It was perfect..It flew slowly straight towards us and of course stopped wonderful ernie Quote Link to comment Share on other sites More sharing options...
Steve Houghton 1 Posted May 31, 2017 Share Posted May 31, 2017 Back when 3 & 4 Squadron were operating Harrier GR4's out of Gutersloh. Germany, the station song was Queens, Another one bites the dust, and I remember attending at least two crash sites. One just a few miles from camp, near to where we had a large bulk fuel installation, and another near Frankfurt where the aircraft had crashed through the last of a row of houses. The brave, selfless pilot stayed with his craft to ensure he kept casualties to a minimum. As I remember, fortunately I think he was the only casualty. Then I was having my lunch at my work place one sunny day when I heard a loud bang and we all ran to the window. A Harrier had been hovering over the runway when something went wrong. The pilot had banged out, but because the aircraft was at an angle at that moment, the pilot ended up in the bomb dump before his chute deployed, and the Harrier crashed on the runway. They always performed great at airshows, and everyone would want to see their display, but they were notorious for crashing. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted June 4, 2017 Author Share Posted June 4, 2017 Posted by Tony Nijhuis on 29/05/2017 21:12:54: 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!!!! Decided to give it another go toady, but made a few modification in particular moving the CofG forward by 1/2" (because of last week's violent 'rear up', positioning the fans at stage1 to 45deg (to give greater forward speed) and decided to keep the quadcopter board operating until the fans all all became horizontal. The wind was quite strong so she was get blown back in the hover so back on the ground I decided to take off at stage 1....(45deg fan position)...doing this the harrier gently rose off the ground, accelerated forward and climbed to around 20' under quad controll before gingerly switching to stage 2 (full transition).....this time, no change in pitch, she just accelerated away into normal flight.......fantastic....Managed about 5 circuits before and decided to land conventionally with no bother.....Finally get somewhere! Doing some further test this afternoon and hovering into a head wind, all the fans need to be set at 10deg forward for a 10mph wing and I would suspect 15deg for a 15mph wind. Quote Link to comment Share on other sites More sharing options...
Chris North 3 Posted June 5, 2017 Share Posted June 5, 2017 Tony, I have never designed a plane so probably have no right making comment but from what I understand wind loading is a function of wind speed squared. Wind Loading = Area x Wind Pressure x Friction Coefficient and, since the model is the same, Area and Friction are constant and so can be ignored. Wind Loading = Wind Pressure = 0.00256 x (wind speed)2 Which means that the wind loading at 15 mph is about 2.25 times that at 10mph (Wind Pressure (.256 llb/ft2 at 10mph and 0.576 llb/ft2 at 15mph) If your fans were angled at 10 deg in 10 mph wind they will need to be angled to give 2.25 times the forward thrust in 15 mph wind. Forward thrust at 10 degrees = Sin 10o = 0.1736 so forward thrust required at 15 mph = 2.25 x 0.1736 = 0.2588 Therefore Sin-1 0.2588 means required fan angle will be 20.3 degrees Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted June 9, 2017 Share Posted June 9, 2017 For some reason I was flicking through Dec 91 RCME and came across this in an article on finishing techniques. No further details. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted July 6, 2017 Author Share Posted July 6, 2017 Its been a few weeks since I last posted so I thought I would give an up date and to nights successful attempt! https://youtu.be/vq03BrLlYxI https://www.youtube.com/watch?v=1xnzU0S81m4 Edited By Tony Nijhuis on 06/07/2017 22:13:45 Quote Link to comment Share on other sites More sharing options...
Lindsay Todd Posted July 6, 2017 Share Posted July 6, 2017 Very impressive Tony, that's quite an achievement Lindsay Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted July 6, 2017 Share Posted July 6, 2017 Congratulations Tony. that is some achievement. Tony B Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted July 6, 2017 Share Posted July 6, 2017 That is very impressive. Quote Link to comment Share on other sites More sharing options...
Josip Vrandecic -Mes Posted July 6, 2017 Share Posted July 6, 2017 After all years of research and valuable and hard work .... this is a great finale ... Thank you very much Sir ! Quote Link to comment Share on other sites More sharing options...
Tim Cheal Posted July 6, 2017 Share Posted July 6, 2017 That's awesome. Well done indeed. Tim Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 6, 2017 Share Posted July 6, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted July 6, 2017 Share Posted July 6, 2017 Paah not a single VIFF in sight.................. Apart from that Fan-blummin-tastic!!!! Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted July 6, 2017 Share Posted July 6, 2017 Looks like you have cracked it, It don`t half shoot off in normal flight mode, it looks like someone was writing messages in the clouds if you look at the video as it takes to normal flight. Great stuff. Steve Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted July 6, 2017 Author Share Posted July 6, 2017 Thanks Guys, This has been very much a personal crusade and I one I will no doubt share at some point. The model and avionics in it current form is quite complicated and reliability is still a slight issue.....as you said Tom, it may need a big corporation to push it into a reliable worldwide product....At some point in the future it has to be shared with global modeling public.....flying it the Harrier this evening has been an experience like no other. If anything the limitation is my flying ability.... the stability of the Harrier is amazing and the only time you can stall it is in normal flight....and if you do, flick it back into hover and she saves her self... What I will be doing is a follow up article in the RCME which will track the changes to this latest prototype and hopefully in a finished colour scheme with scale detail..... Quote Link to comment Share on other sites More sharing options...
Andy G. Posted July 7, 2017 Share Posted July 7, 2017 A very smooth transition from hover to forward flight, very impressive! Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted July 12, 2017 Author Share Posted July 12, 2017 Some more testing done in the last few days and a little more detail added including intakes and canopy....Really getting the hang of flying the Harrier now....but weight is still a limitation at 1750g....Almost finished a Depron version which has reduced the AUW by 20% (1400g).....with luck this should give around 3.5 min hover time or 8mins normal flight time on a 4500 4S lipo..... Note the anti-stall fences on the wing....an absolute must as i have found out to my cost on early prototypes Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 12, 2017 Share Posted July 12, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted October 8, 2017 Author Share Posted October 8, 2017 For those who have not seen the you tube video of the Harrier flying today, here it is....Its pretty well sorted now and the final article will be in the December issue of RCM&E https://youtu.be/V8rbAPbuJ9k Edited By Tony Nijhuis on 08/10/2017 22:28:18 Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted October 9, 2017 Share Posted October 9, 2017 A better link for you Tony. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted October 9, 2017 Share Posted October 9, 2017 By the the way Tony excellent. Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 9, 2017 Share Posted October 9, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
KiwiKid Posted October 9, 2017 Share Posted October 9, 2017 Posted by Tom Sharp 2 on 09/10/2017 02:42:16: and now for my next trick Antigravity? It's just about as hard to achieve. Well done Tony - people have been trying to crack this nut for over 30 years with varying levels of success. Skymasters jets have recently put a phenomenal amount of R&D work into a turbine version and are currently doing airframe flight tests with another motor before fitting the 40KG thrust variable thrust engine they have developed in conjunction with JetCat. Quote Link to comment Share on other sites More sharing options...
Rich too Posted October 9, 2017 Share Posted October 9, 2017 Excellent it even sounds great with those four fans Quote Link to comment Share on other sites More sharing options...
Toni Reynaud Posted October 9, 2017 Share Posted October 9, 2017 Brilliant achievement and wonderful to see. Congratulations. Quote Link to comment Share on other sites More sharing options...
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