stuey Posted May 2, 2015 Share Posted May 2, 2015 Looking good Tony As far as the hook location goes, I have read on rc groups many times there is a basic starting point. You measure from the nose to the cg. The hook goes 2/3 of that measurement from the nose. Say nose to cg is 600mm, the hook goes 400mm from the nose. That explanation is just in case my statement makes no sense btw! If you were to hang the model on the hook with a vertical cord, there would be an approx angle of 20 degrees from the vertical. Too low an angle is not good trust me! Hope this helps. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 2, 2015 Author Share Posted May 2, 2015 Thanks Stuey....makes perfect sense. Quote Link to comment Share on other sites More sharing options...
Alan Pennington Posted May 3, 2015 Share Posted May 3, 2015 Nice one Tony. If landing gear was fitted could it be still hand launched. Alan Quote Link to comment Share on other sites More sharing options...
Steve Adams Posted May 3, 2015 Share Posted May 3, 2015 That Hawk looks gorgeous Tony can't wait for the flying report and plan in RCM@E any idea about which month it will be in? I really wish I had your talent to produce such incredibly well flying desirable aircraft! Kind Regards Steve Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 5, 2015 Author Share Posted May 5, 2015 Thanks Steve for your kind words.... Look back on page 2 to view the flight test.... Not sure when this will be out but i guess late summer Alan, there is nothing to stop you fitting retracts and hand launching. It adds another 4oz so the concern is the weight may be too much for some to manage. Andy, who launched the model in the video, is strong lad and gave it a good chuck....the next test is to see exactly how slow we can throw the model and still be able to get it away. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 16, 2015 Author Share Posted May 16, 2015 Finally finished Hawk No.2....AUW is 5lb 8oz with a 6S 4000mah. The strip down Hawk for hand launch is 4lb 8oz with a 6S 3300mah pack, no retracts and no flaps.....hopefully some test flying this weekend Edited By Tony Nijhuis on 16/05/2015 00:25:52 1 Quote Link to comment Share on other sites More sharing options...
stuey Posted May 16, 2015 Share Posted May 16, 2015 They look great! I hope the hand launch goes well as its my only option, or a bungee. Quote Link to comment Share on other sites More sharing options...
Steve Balaam Posted May 16, 2015 Share Posted May 16, 2015 With respect to the hook position for bungee launch. I have built several EDFs for bungee launch in the past. My rule of thumb was to mount the hook 2/3rds. of the way between the nose and the CG. That way models come off the ramp in a nice flat attitude to pick up flying speed. The hook attachment area need to be substantially strong to take the loads I use to inlay a substantial ply or wood plate in the desired area Hope this helps Steve B Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 17, 2015 Author Share Posted May 17, 2015 Thank Steve...I think that ties up with other suggestions. Well it been a mixed day of failure & success and Headcorn aerodrome this morning..... The hand launch Hawk didn't go to plan unfortunately..... Although the launch it self appeared ok, with a slight nose up attitude, the model rolled slightly to the right and with the speed not be there to correct it, she rolled in..... At nearly 4.5lbs it dose prove that the hand launch is critical....When we first tested for hand launch, as you can see from the video on page 2, it needed quite a throw. Today we tried a softer touch, and more in line with your average club launcher.....clearly the speed of launch is critical so we proved the theory that you either have to have an Olympic javelin thrower in your club, or you need a bungee. My guess is the bungee is more common place So a hard lesson was learnt today, but a very useful one. So on to Hawk No.2 and the retract version with scale detail, the Hobbyking 11 bladed 6S fan unit and another pound of weight.... When we tried the retract version back in early spring, we couldn't get is it ROG. What a difference a couple of months make with a hard & short mown strip. This time there was no such drama.... The throttle was opened and she shot down the strip.....Holding quite a bit of up elevator, she rotated and was away. ......rock steady. We managed two flight and got the flying shots for the magazine before the LIPO gave out..... I plan to do some more 'tweek' testing next week. Now the flying shots are out of the way, I can enjoy the model in the comfort of my own club patch.....and practice my landings! Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 19, 2015 Author Share Posted May 19, 2015 A couple of flying shots of the hawk taken last weekend Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted May 19, 2015 Share Posted May 19, 2015 Shame about the broken one, but the flying shots look spot on sir Quote Link to comment Share on other sites More sharing options...
stuey Posted May 19, 2015 Share Posted May 19, 2015 As Andy said, shame about the handlaunch version. It does look very good flying! Are you going to have the chance to try a bungee launch Tony? Quote Link to comment Share on other sites More sharing options...
Steve Adams Posted May 19, 2015 Share Posted May 19, 2015 Absolutely Stunning Tony, Will the plan be in mag before the mossie? Your persistence with these model jets seems to always pay off in the end this seems like the Vulcan were it not for the failure you wouldn't have had success. You truly are a master Keep up the good work Kind Regards Steve Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 20, 2015 Author Share Posted May 20, 2015 Thanks Steve for your kind words.......If you look hard enough at any failure, there will always be something positive you can take from it and persistence always seems to pays off.....touch wood I have never used a bungee launch before and as the broken hawk would have been the test bed....im not planning on building another so I'll show a hook position but it will be down to the experts out there to test the theory... As we have all the photos, we shall pop the plan in the September or October issue, just before the Autumn Special and the mossi Quote Link to comment Share on other sites More sharing options...
Bill_B Posted May 20, 2015 Share Posted May 20, 2015 THESE are far superior to the simple bungee and stake normally seen at clubs and are very easy to make. It's also more compact than the launch ramp systems sometimes employed. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 20, 2015 Author Share Posted May 20, 2015 Yes I have seen Jepe using these years ago Dose anyone know where I can get a suitable hook or is it a case of making one? Quote Link to comment Share on other sites More sharing options...
Bill_B Posted May 21, 2015 Share Posted May 21, 2015 For a hook I usually use an old piece of partially threaded metal pushrod and put an 80° bend into it just where the threaded part begins. The smooth part of the pushrod is where the bungee ring slides onto, and the threaded end goes through a ply plate let into the fuselage bottom with a nut & washer either side. I find this is more than adequate for EDFs up to 70mm. Quote Link to comment Share on other sites More sharing options...
Bill_B Posted May 21, 2015 Share Posted May 21, 2015 A picture says a thousand words...... Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 21, 2015 Author Share Posted May 21, 2015 Thanks Bill....very helpful Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 26, 2015 Author Share Posted May 26, 2015 So another weekend of testing and the model is pretty well sorted now. The heavier retract version I have concluded is strictly for tarmac or very short cut strips. I have flown the hawk at both Hastings and Headcorn grass strips. The Hastings strip although is longer is not cut as short as Headcorn and so it did struggle to get off. Wasn't helped by the strip just being cut and the fan ingesting grass cuttings. So the Headcorn strip proved to be the better this weekend. The 11 bladed 6S Hobbyking fan is great and model sound like an turbine model. Three flights yesterday and all very enjoyable. Its seems a good head wind dose help to get the model off and help slow her down for landings. She does come in at a rate of knots so learning to use the flap will help. Having retracts with this size and weight of model dose mean your landings have to be spot on every time. I did pull one of the retracts out on landing yesterday...due mainly to my naff flying ability....but hey, the repair was easier than i thought. Now sitting here weighing up the pros and cons of the retract version against the lighter bungee launch (don't bother to hand launch), the benefits are weighing heavily towards the retract-less simpler and lighter version. This is based on the flying seems a little crisper (due to the lighter weight) and avoidance of retract damage. Belly landing the model is a doddle.... I have also concluded that with a 70mm fan, you really are at the limits of a plan built model. I say this because a conventional balsa wood model can not compete against the lightness of a foame, which is where you can find most of the 70mm fan designs. Notwithstanding this, the Hawk has ample power once airbourne and will fly on half stick I think for future designs, I'll use the 90mm fan units as a basis. Quote Link to comment Share on other sites More sharing options...
Bill_B Posted May 26, 2015 Share Posted May 26, 2015 THIS may be of use to help launch the Hawk, although personally I prefer the JEPE dolly. Quote Link to comment Share on other sites More sharing options...
stuey Posted May 26, 2015 Share Posted May 26, 2015 Thanks for the update Tony. Looking at the pics, I cant see any reason why a 80mm fan would not go in there. It is going to be a 6S model anyway, so its a step up from the current 4S models. That is until my Freewing 90mm Eurofighter is ready! I look forward to the plan, and to see if it will take the 80mm. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted May 27, 2015 Author Share Posted May 27, 2015 Thanks Bill, I'll be trying the JEPE one..... Thanks Stuey....its not so much the power but the scale retract with tiny wheels that limits the model and flying location. Moving to a slightly larger size of model, the weight will not greatly increase but its usefulness will. If you bulge the fuselage slightly of this Hawk, an 80mm fan would fit very easily, but its not the answer....I do like to keep the wing loading as low as possible and generally larger models allow this to happen.... Quote Link to comment Share on other sites More sharing options...
Tripwire Posted June 21, 2015 Share Posted June 21, 2015 I saw a copy of RCM&E today and it was stated therein that the plan should be included in either the August or September issue. I have marked my calendar accordingly. Earlier in the thread, someone encouraged TN to design a Folland Gnat. I've long wanted to build one of those - a great-looking aircraft. If TN could turn his talent to designing one, I would be a very happy man. Edited By Tripwire on 21/06/2015 16:16:52 Quote Link to comment Share on other sites More sharing options...
Tony F Posted June 21, 2015 Share Posted June 21, 2015 I'd vote for a TN Buccaneer , how about it Tony Tony Quote Link to comment Share on other sites More sharing options...
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