Alan Gorham_ Posted March 28, 2017 Share Posted March 28, 2017 Hi All I'd really appreciate your opinions! I came along to spectate at the Orme last October and although the lift seemed light I loved the flying and the spectacular site. Having totally failed to build a proper PSS model over the winter, thoughts turned to converting my old Nijhuis "funfighter" style Hawk and chucking it off a cliff with you all in April. As you can see, the model is not very scale in outline and has a big-ish wing. Ignore the random holding it in the picture! I've taken out the .25 2 stroke, tank and throttle servo and reckon my AUW will be close to 25 oz. Bearing in mind the wing section is carved from 9mm balsa sheet (although it seemed a very efficient flyer with a motor up front!) - What are my chances of success? Thanks Alan Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted March 28, 2017 Share Posted March 28, 2017 Good, Alan. Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted March 29, 2017 Share Posted March 29, 2017 Should work. Fill over the gap for the engine, get the rx battery right up behind the spinner and screw the spinner direct to a couple of ply blocks to retain the battery. Check the CoG, get somebody to throw it off the cliff and see if it flies. Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted March 29, 2017 Author Share Posted March 29, 2017 Thanks Chris, those are broadly my plans. Already proved I can balance it with a decent sized battery where the engine used to be, but I am not going to use the awful spinner, I'm making a more scale looking nose with landing light as my access to the battery. My main concern is at 25 oz AUW do you think it will fly in light lift or will it need a good blow? Quote Link to comment Share on other sites More sharing options...
steve howarth Posted March 29, 2017 Share Posted March 29, 2017 Hi Alan, whilst I'm sure that there's poeple out there far better qualified than me to advise you on this, these are my thoughts, for what they're worth! Perhaps this is stating the obvious but if your model needed the engine to get it up to say, 15mph to get it airborne, then you're going to need at least that windspeed to chuck it off the Orme, provided it doesn't weigh any more with the battery than it did with the engine in place. If you worked out your wing loading it may give you a better indication of the necessary wind speed needed. I'm sure wing section would also play a part in this as well as which face you launch it from on the Orme. The lift is better on some faces than others for a given wind speed. I have just done the same with a Piper L4 Grasshopper, photo below. Replacing the engine with a 4 cell sub C NiMh battery balanced it perfectly. This weighs in at 96ozs and with a wing area of 6ft sq give me a wing loading of 16oz/ft sq. I think this is relatively light and will be looking for about 15/20mph. My Aermacchi MB339 has a wing loading of about 25oz/ft sq and I wouldn't consider anything less than 30mph from one of the better faces. With a smaller untried model, I will often give it a gentle test chuck over the heather at the back of the slope to see how it glides, that the control throws are about right etc but as yours has alredy flown, this may not be necessary. We are blessed with abundant lift on the Orme so provided the wind speed is sufficient, you should have a ball with it! Hope this helps. Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted March 30, 2017 Author Share Posted March 30, 2017 Steve - good information, thanks for that. The model's wingloading with engine was 24oz/sq. ft, but I have reduced weight by 8 oz by binning all the engine related bits, so I am hopeful. PS - I flew the Phantom I bought from you in October successfully and it's now stripped down for a refurb/repaint! Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted March 30, 2017 Share Posted March 30, 2017 The gliding qualities of a model is not just about lift and wing loading but it is also about drag. Draggy models won't penetrate well, it will also make them poor gliders with a steeper glide ratio. In the teeth of a gale off the Orme you can almost get a house brick to fly - just not very well! I think your Hawk should be successful Alan in the right conditions. You might consider a bit of surgery to reduce (or remove) the air intakes to eliminate a bit of drag but try it as it is to start with and see how it performs. Just my 2p worth. Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted March 30, 2017 Share Posted March 30, 2017 Hawk's are pretty sleek machines anyway, it should go well. Nice scheme to see on the slope too - hope to get some formation flying in with my little black one Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted March 30, 2017 Author Share Posted March 30, 2017 Thanks Piers Its hard to quantify "draggyness" without a windtunnel I guess, but having deliberately glided the model down on a couple of occasions with a dead engine, I am encouraged that things might be ok. I think my weight reduction measures, coupled with the fact the draggy prop blades wont be there any more might mean I don't need a gale to stay aloft. I'm really reluctant to take off the dummy air intakes as the model was meant to be a quick and dirty conversion to have something to fly. If I try it and it doesn't go well, I'm quite happy to build something more suitable! Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted March 30, 2017 Author Share Posted March 30, 2017 Hi Andy I would be delighted to get in formation with your lovely Hawk! I'm greatly encouraged to give this a try now - next stop the big worm's head! Re the colour scheme - I find it hard to see on a typical grey day up here on the North East coast, so flying from a slope close-in and low will be a good help Edited By Alan Gorham_ on 30/03/2017 11:48:02 Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted April 10, 2017 Author Share Posted April 10, 2017 Just a quick follow up.... I took the converted Hawk to Llandudno at the weekend. Thanks to Steve Howarth, Mark Kettle and Phil Cooke for your advice, help and encouragement. Without it I'd have been too chicken to chuck it off the edge. I was well out of my comfort zone, but after a couple of moments in bumpy air and sorting out the trim I had an absolute ball trying PSS flying in great lift. What a thrill - why haven't I tried it sooner?! Mr. Howarth especially - you went above and beyond the call of duty spending so much time reassuring me and talking me round when you could have been flying yourself. I'm definitely hooked. Photo evidence: The one with the random holding it again courtesy of Phil Cooke. Others by me. Loved the Fouga Magister in Luftwaffe colours! Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted April 10, 2017 Author Share Posted April 10, 2017 Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted April 10, 2017 Author Share Posted April 10, 2017 Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted April 10, 2017 Share Posted April 10, 2017 I don't think I saw it fly Ian, but glad you've got the bug. The Fouga is my beast, but she really needs a steel spar instead of the fibreglass one. See you at another meet soon! Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted April 10, 2017 Share Posted April 10, 2017 Posted by Alan Gorham_ on 10/04/2017 21:11:54: Just a quick follow up.... I took the converted Hawk to Llandudno at the weekend. Thanks to Steve Howarth, Mark Kettle and Phil Cooke for your advice, help and encouragement. Without it I'd have been too chicken to chuck it off the edge. I was well out of my comfort zone, but after a couple of moments in bumpy air and sorting out the trim I had an absolute ball trying PSS flying in great lift. What a thrill - why haven't I tried it sooner?! Mr. Howarth especially - you went above and beyond the call of duty spending so much time reassuring me and talking me round when you could have been flying yourself. I'm definitely hooked. Photo evidence: The one with the random holding it again courtesy of Phil Cooke. Others by me. Loved the Fouga Magister in Luftwaffe colours! Friendly bunch these PSS'ers but be warned they'll throw anything off the edge for you whether it'll fly or not! Sorry Peter! Glad you got to have a go too. It's very addictive and the conditions on Sunday were very good for maidening a model. Still takes a lot of guts the first time and faith in what people you've only just met are telling you! Will you and the Hawk be joining us for the next bash? Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted April 11, 2017 Share Posted April 11, 2017 It was a pleasure to meet you Alan. I think your simple constructed Hawk was brilliant. What a great model to introduce you to slope flying. I'm interested and I'm sure others would be interested in details and photographs of your conversion If there is any new flyers are considering a go at PSS slope flying them a Tony Nijhuis 40" BAE Hawk RCM&E Plan published in July 2006 is a easy starting model, with a good result. Alan you did share with me that you have flown the model for over 7 years with a 0.25 up front, and the biggest change to slope flying he found is that the flight time is altered from 5 / 7 mins on glow fuel to over +20 mins when sloping. Tony Nijhuis RCME **LINK** Quote Link to comment Share on other sites More sharing options...
steve howarth Posted April 11, 2017 Share Posted April 11, 2017 Your Hawk flew really well Alan. You had obviously set it up properly. Even after 35 years of PSSing, it is still an apprehensive moment when chucking your freshly built or converted model off a sea cliff! The day it stops being a thrill is the day I'll pack it in! Welcome to the PSS fraternity, we really are a friendly bunch. Get the next model on the building board. Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted April 11, 2017 Author Share Posted April 11, 2017 I am fired with enthusiasm to build a "proper" PSS model now. In fact more than one! But I'm the world's slowest builder, so my aim is probably to build over the coming winter ready for next spring. I will try and make the Orme in August and October this year though with something flyable. I really fancy building something big and glider-ish. The Hawk was literally a zero-cost no emotional loss model that I could not get upset about losing if it didn't work. As Mark says, it was my winter hack and has done 7 winter's service powered by an SC .25. Conversion was quick and dirty and I didn't take any pics. I just took out the motor, mount, tank and throttle servo and fished the Rx battery out from the tail. That fitted in the vacant engine bay and I filled the hole for the cylinder head with high density polyurethane foam. The foam was smoothed to shape and I glassed over the outer surface of the foam. I made the node cone in a similar way, using vertical and horizontal ply keels, then filling out with foam and glassing over. A quick blow over with paint and job done. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted April 11, 2017 Share Posted April 11, 2017 What a good conversion Alan , welcome to the group. Quote Link to comment Share on other sites More sharing options...
Harry Twist Posted April 11, 2017 Share Posted April 11, 2017 Great conversion Alan - saw you flying the Hawk - it flew really well and you looked like you were having a ball! There is lots of choice available for your next PSS model! Have a look and get planning away! Quote Link to comment Share on other sites More sharing options...
steven patey Posted August 8, 2017 Share Posted August 8, 2017 would the 42" edf hawk (which looks more scale to me) be any good to convert to pss? http://www.tonynijhuisdesigns.co.uk/HawkEDF.html Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted August 9, 2017 Share Posted August 9, 2017 There's certainly no reason why she shouldn't be a good flier. I'd check that the intakes haven't been made oversized, as is the norm for EDF models, as they will be great big drag buckets. Try to reduce the size if this is the case, and also blank them off. Whatever happens, build as light as possible. Lastly, have you considered the Andy Conway Hawk at all? They are lovely fliers, even with a scale sized wing. Here are some pics of various PSS Hawks. Quote Link to comment Share on other sites More sharing options...
steven patey Posted August 9, 2017 Share Posted August 9, 2017 Thanks Andy, had forgotten about the Conway one. It looks a bit bigger too. I'm tempted to go for the Nijhuis one anyway cos of the wood pack that's available. (I can't be bothered to do a full scratchbuild at the moment). It would be interesting to see how it turns out compared to the Andy Conway one. Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted August 9, 2017 Share Posted August 9, 2017 No probs - yes it's a good reason to go for the TN one - saves a lot of scroll saw time! Please keep us informed either way, and maybe run a build thread if you can? Quote Link to comment Share on other sites More sharing options...
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