Tony Nijhuis Posted February 17, 2015 Share Posted February 17, 2015 Well it seems that RCM&E are not content with just one Special a year, they have now decided to go for another.... two specials (the existing Autumn and the new Spring Special) and that means two plans from yours truly!!!!! Now fortunately I had the next TND project on the go which was a DF powered Hawk so this is now going to be the Spring Special Plan. After the roaring success of the DF Vulcan i though may be I have been missing a trick with this ducted fan lark....So the Hawk seemed the next logical step....So 42" span 4.5lb AUW very near scale, flaps and retracts and 70mm 6S fan unit to power it. Test flight is scheduled for next week so lets hope for some dry weather... Happy days Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted February 17, 2015 Share Posted February 17, 2015 Good luck with the weather and maiden Tony John Quote Link to comment Share on other sites More sharing options...
Olly P Posted February 17, 2015 Share Posted February 17, 2015 Sounds good - and a likely conversion candidate for PSS..... Quote Link to comment Share on other sites More sharing options...
Mowerman Posted February 17, 2015 Share Posted February 17, 2015 Sorry, everyone builds Hawks, should have been a Folland Gnat with Finnish and Indian Variants. Quote Link to comment Share on other sites More sharing options...
Alan Jarvis Posted February 17, 2015 Share Posted February 17, 2015 Just built the Vulcan and now looking forward to the Hawk. Tony, any chance of giving some details of the motor/fan etc so I can put them on my shopping list. Quote Link to comment Share on other sites More sharing options...
Pete B Posted February 17, 2015 Share Posted February 17, 2015 Off-topic posts removed, folks - this thread is about a DF Hawk. If you wish to discuss other matters please start a thread in the appropriate section, thanks Pete Quote Link to comment Share on other sites More sharing options...
FastFlyer Smyth Posted February 17, 2015 Share Posted February 17, 2015 very much looking forward to this one Tony !! Quote Link to comment Share on other sites More sharing options...
Gavin Livsey Posted February 17, 2015 Share Posted February 17, 2015 I'm in and watching. Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted February 17, 2015 Share Posted February 17, 2015 well done Pete..tony lets have a photo or 3 please...the hawk will go down well......especially red arrow colours etc.. ken Anderson...ne...1...... hawk dept. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 17, 2015 Share Posted February 17, 2015 Yummy Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted February 17, 2015 Share Posted February 17, 2015 Yuppie Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted February 17, 2015 Author Share Posted February 17, 2015 Ok some development photos to whet your appetite I have used an old Lander 68mm 5-bladed unit with a 2600kvs motor on 6S. This should deliver around 2.1kg of thrust which in theory will give a 1 to 1 thrust to weight ratio...!!! The plan is this model has to RO cut grass which is a big ask as the retract wheels are quite small....still we shall see I have kept this build very simple and very near scale so hopefully it will attract the the not so practiced builders out there and also the rooky DF modellers wanting to have a go (of which I am one of them) Quote Link to comment Share on other sites More sharing options...
Steve Adams Posted February 17, 2015 Share Posted February 17, 2015 Your becoming a dab hand at this edf malarky Mr N! When this little beauty is done,will you do anymore edfs sir? If so I would love to see a Harrier, Meteor NF 11,or a ME 262 I really love jets as you can tell, particularly the classic ones are the best Steve Quote Link to comment Share on other sites More sharing options...
stuey Posted February 18, 2015 Share Posted February 18, 2015 Looks like just what I need! And my wife cant complain as she works at Air Command and my 3yr old son loves the Red Arrows. It would most likely be a belly lander for me and maybe a bungee launch depending on the static thrust. Are you planning to make an intake duct into the fan or leave it as per the pics? Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted February 18, 2015 Share Posted February 18, 2015 Posted by Olly P on 17/02/2015 14:55:10: Sounds good - and a likely conversion candidate for PSS..... That's just what I was going to say Looking good Tony Quote Link to comment Share on other sites More sharing options...
Alan Jarvis Posted February 18, 2015 Share Posted February 18, 2015 Tony I am just wondering if it really needs a 6s battery I would have thought with a decent 11 blade fan and 4s would work. There would be a good saving in weight and cost, whilst it may not give 1:1 I am sure it would not be far off. Your Vulcan only uses 3s although not a speed machine. Can we have a 90mm Eurofighter Typhoon next. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted February 18, 2015 Author Share Posted February 18, 2015 Well its now ready for test flying and the AUW is just over 2.1kg. The fan unit I have measured is giving around 1.6kg of thrust which ties up with the Lander test video on their web site. Ran the model around the lumpy back garden and was able to push her round no problem.....with a summer mown strip, she ROG no problem. Alan, your comment about the 4s version; I have a Dr MT 11 bladed 4S unit from hobby king, bought as an alternative. The thrust is similar to the Lander I'm using but the weight is 60g more. Because the 4S will draw more current to deliver the same power as the 6S, the batteries will need to be of larger capacity...at least 5000mah.....(I used a 3300mah 6S for the Lander fan).......QED to deliver the same performance and duration, the 4S version actually turned out to be a heavier install......the key point to bear in mind here is use as higher voltage as possible as this will deliver the power at less current. 6S is a great size because most modern cheap charges and ESC will cope with 6S. Once you go above 6S, the cost of ancillary equipment increases alarmingly. Stuey's point concerning intake ducts is an interesting one.......there is a benefit to a smooth intake but not a much as one might think. the most important element is the 'bellmouth' intake to the fan and most manufactures now fit these as they increase the performance and therefore placing less reliance on the modeller making smooth intake ducts or a kit manufacture producing a light composite product which adds weight. If we can avoid the difficulty of intake ducts on plan build models, it really opens up a more simplicity approach to ducted fan modelling with out be penalised on performance. Interestingly I have done some test with the Lander fan both in and out the model and there appeared no loss in performance!!! Based on this simplistic and if the Hawk design is successful, I will certainly be adding more EDF's to the range ...happy days Quote Link to comment Share on other sites More sharing options...
Bill_B Posted February 18, 2015 Share Posted February 18, 2015 If going for a bungee launch, surely the retracts and flap servos could be omitted saving a fair amount of weight and thus not only increasing the performance, but giving even better slow speed handling too. I might just give this one a punt. Quote Link to comment Share on other sites More sharing options...
stuey Posted February 18, 2015 Share Posted February 18, 2015 Thanks for the feedback on the ducting Tony. I have seen a few larger edf builds where there is no specific ducting and the fan is fitted with a bell inlet. I have also noted that turbine models have very little ducting and have all sorts of bits in the airflow, but I guess they have thrust to spare. I would like to see a Eurofighter too, preferably 70mm but scaling up to 90mm would be easy enough. Please!! Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted February 18, 2015 Author Share Posted February 18, 2015 Correct.....there's no need to duct the inlet on to turbines....they simply deliver enough thrust so inlet duct become superfluous. The great thing with the current batch of EDF units is they are following in the foot steps of turbines....exciting times for EDF Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted February 18, 2015 Author Share Posted February 18, 2015 ready and waiting to test Quote Link to comment Share on other sites More sharing options...
stuey Posted February 19, 2015 Share Posted February 19, 2015 Looking good! It would be great to have some more edf airframes to choose from. There were loads of foam airframes a few years ago, but the choice has dropped right away. There is a lot of good edf kit around and not much to put it in! 70mm is a good starting point imo. I must start on my 90mm Eurofighter soon... Best of luck for the maiden Quote Link to comment Share on other sites More sharing options...
Alan Jarvis Posted February 19, 2015 Share Posted February 19, 2015 Stuey Do you have a plan or kit for the Eurofighter or just your own design as I would like one. I used to have the Freeing foam one but no more. Alan Edited By Alan Jarvis on 19/02/2015 17:59:54 Quote Link to comment Share on other sites More sharing options...
stuey Posted February 19, 2015 Share Posted February 19, 2015 No sorry I was referring to my Freewing one. I also have an ArtTech one and the Graupner/Sapac version. So you can tell I like them! Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted February 21, 2015 Author Share Posted February 21, 2015 Sometime thing just don't work out!!! this was the sorry sight at 4pm today after 4 attempt to get the model into the air ROG....or should I say mud! The reality was the ground was too claggy for the 38mm wheels and she didnt want to rotate. One of the problem with having to design and test in the winter especially a ducted fan.... So rather than try a hand launch, i put more elev throw and moved the batteries back to help rotating and put half flap in....it all ended with a rearwards Cof G and as she finally got air bourne it was on the stall point and the fight started...i lost after about a 3-4 seconds Edited By Tony Nijhuis on 21/02/2015 22:31:51 Quote Link to comment Share on other sites More sharing options...
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