Mark Kettle 1 Posted September 29, 2014 Share Posted September 29, 2014 Boy that's nice, excellent Colin. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted September 29, 2014 Share Posted September 29, 2014 It looks very tidy and aggressive Colin, not be long now John Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted September 29, 2014 Author Share Posted September 29, 2014 Thanks chaps. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted September 29, 2014 Share Posted September 29, 2014 Looks Great Colin Steve Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted September 29, 2014 Author Share Posted September 29, 2014 Cheers Steve. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted September 30, 2014 Author Share Posted September 30, 2014 Spinner painted, we'll see how well the paint stays on the aluminium. I managed to get a working spinner which runs true by grafting one of my spun aluminium versions onto a standard Irvine unit. Before it flies I will give it and the prop a very careful balance check. The contraption under the tail represents the deflector that was fitted to the Seafang and late Seafire's with the sting type arrester hook to prevent the arrester cable fouling the tailwheel and rudder on deck landings. Without going over the top I've added a bit of lining detail. The F32 had PR camera windows on either side of the fuselage, so I will simulate those with black paint or stickers. Also, there were landing lights under the fuselage behind the wing so I will drill two holes there but leave them open to encourage air passing through from the nose intake to go over the battery. The exhausts are open for the same purpose, so although the intake is small, it's perfectly positioned behind the prop and I hope will be sufficient to help keep things reasonably cool. I am going to make a launching bogie for this, I think I will struggle with an under-arm launch because I can't get my hands comfortably in a good position, they're not big enough! Although I've never tried one, I've seen a number work very well. If anyone reading this can give me advice, I'd be grateful. Quote Link to comment Share on other sites More sharing options...
Graeme Poke Posted September 30, 2014 Share Posted September 30, 2014 Oh heck Colin, I'm loving that. It looks terrific. Well done on getting it finished before all hell breaks loose on the Chipmunk! Good luck on the flight. I think this will become a retirement project, ......along with at least 20 others! Ah well, it's nice to dream. Be well, Graeme Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted September 30, 2014 Author Share Posted September 30, 2014 Thanks Graeme. Now I've got this far I'm beginning to take it seriously. Don't want to wreck it with one careless chuck, so a bit of planning is required. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 11, 2014 Author Share Posted October 11, 2014 It's been a frustrating few days because of work commitments and I've done no building. However managed to knock a launch trolley together, hope it works. We have good hard runways at Fradley, so fingers crossed that it's a safer option for initial flights than hand launching. Somehow I'd put one of the cannons in the wrong position, so I've removed it for re-positioning. Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted October 11, 2014 Share Posted October 11, 2014 looks wonderful and the dolly looks ok as well. cant wait to see the maiden. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted October 11, 2014 Share Posted October 11, 2014 Hi Colin the dolly looks great , but a little heavy what is it made of ? Don't forget that the motor now has to get that dolly up to flying speed as well now . Steve. Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted October 11, 2014 Share Posted October 11, 2014 Looking good Colin, Not sure how you went about painting the spinner but, using "prymol" as a primer does help most paints to adhere well to aluminium Of course the clever thing with the dolly will be landing back on it seriously though as an assist to dolly launching a soft bungee attached to the dolly and well stretched can help get things up to speed pretty quick though that usually requires a four wheel dolly to allow the dolly to overrun the bungee line without snagging, allthough the model is usually well away before bungee is fully retracted Edited By Phil Winks on 11/10/2014 19:19:00 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 11, 2014 Author Share Posted October 11, 2014 Thanks chaps. I appreciate your observations. Stephen, the main structure is balsa. The wing bearers are 3mm Liteply, the wheel mountings are 3mm ply., wheels are foam I appreciate your comments about weight and I did wonder about it, I haven't checked it but I will. There are certainly a few things that I can do to shave it down a bit. Phil, I note your observation about using a bungee. The reason I chose a tricycle lay-out is because it naturally tracks straight and I thought that might be helpful. I'd have a problem setting the bungee up because it's a hard runway, but it's a thought. Thank you. I know that using an etch primer helps with paint on aluminium but I'd never thought of Prymol, which I have got. Good idea. The spinner is abrasive linished and that also helps with adhesion on aluminium. So far, so good, but if it comes off I will try the Pry-mol. I like the idea of landing back on the dolly! Could be an alternative to a flight deck, I suppose. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 11, 2014 Share Posted October 11, 2014 See a few taken off on dolly's and mostly been o.k, hard runway is a plus so you should be able to get good speed up, good luck with it Colin. John Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted October 11, 2014 Share Posted October 11, 2014 We use a 20kg cast iron scales weight, or 2, on our hardened runway mate. what you could possibly do is use two bungee cords with a length of non stretchy line in between and anchor the bungees either side of the runway with the centre cord running through a loop on the front of the dolly,(not attached just passed through) that way the dolly would just continue between the anchor points at the end of its run, and any imbalance in pull from the bungees would simply end up with the cord sliding sideways through the loop on the dolly, it would be much like using a steam catapult not that I'm sure the original would've done, not sure when they were introduced. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 11, 2014 Author Share Posted October 11, 2014 Thanks John and thanks again Phil. That's a bungee idea I hadn't heard of before, works just like an arrester hook in reverse! I think the Navy dreamed the steam catapult up in the fifties and then the Yanks copied it. Before that the Fleet Air Arm used rocket assisted take-off (RATOG) for overweight launches, although I think I'll take a rain-cheque on that one! Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted October 11, 2014 Share Posted October 11, 2014 yes I agree Colin, sounds like a recipe for a bonfire Quote Link to comment Share on other sites More sharing options...
ROY DAVIES 1 Posted October 11, 2014 Share Posted October 11, 2014 What a super job you have done. Best wishes on the maiden and may your landing be a smooth one. I have been reading from afar in as much as I have been reading about the build via my eMail, so after the latest posts I felt I must have a look. Regarding paint on the spinner. At my job I was making up facias for our aircraft weighing scales from aerospace grade alloys and had to prime them. I went to the local auto' paint shop and bought an etch primer in aerosol form. It smelled quite strongly of phosphoric acid which etches its way into the surface of the metal and is highly resistant to peeling and scuffs. So next time! Keep the posts coming, I will be in hospital next Monday to have the 'pump' replumbed, it involves a large pair of snips I believe ( 1 year earlier than was promised I am lucky) so I will catch up with all the news later in the week if able. And I will answer your 'requests' Colin when I am up and at it at home. My Jemima and other projects are on hold it seems. Quote Link to comment Share on other sites More sharing options...
ROY DAVIES 1 Posted October 11, 2014 Share Posted October 11, 2014 What a super job you have done. Best wishes on the maiden and may your landing be a smooth one. I have been reading from afar in as much as I have been reading about the build via my eMail, so after the latest posts I felt I must have a look. Regarding paint on the spinner. At my job I was making up facias for our aircraft weighing scales from aerospace grade alloys and had to prime them. I went to the local auto' paint shop and bought an etch primer in aerosol form. It smelled quite strongly of phosphoric acid which etches its way into the surface of the metal and is highly resistant to peeling and scuffs. So next time! Keep the posts coming, I will be in hospital next Monday to have the 'pump' replumbed, it involves a large pair of snips I believe ( 1 year earlier than was promised I am lucky) so I will catch up with all the news later in the week if able. And I will answer your 'requests' Colin when I am up and at it at home. My Jemima and other projects are on hold it seems. Quote Link to comment Share on other sites More sharing options...
ROY DAVIES 1 Posted October 11, 2014 Share Posted October 11, 2014 Regarding a catapult, you could put a low powered one working as a 'V' sling shot from two points it wouldn't foul the prop then. You could do dry runs with the dolly ballasted up to test the stability and acceleration this way too. Thin streamline wheels will aid acceleration but could a bumpy ride a larger diameter would help there. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 11, 2014 Author Share Posted October 11, 2014 It's nice to hear from you Roy and I do hope that your hospital trip is brief and successful, as I am sure that it will be. There are some really useful ideas coming out for catapult boosting the take-off dolly and your suggestions are appreciated. I'm considering all of this very carefully. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted October 12, 2014 Share Posted October 12, 2014 I would put bigger diameter wheels on and put some lead at the front of the dolly and have more dolly area behind the main mass the dolly will know which way to go - even put finning under the rear axle like F1 car rear end nice project by the way Colin. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 12, 2014 Author Share Posted October 12, 2014 Thanks Mark, I realise that what I'm hearing from you and other mates is the voice of experience, something I don't have on this subject. My thinking was:- Although I've not checked the wattage yet, the power set-up is the same as the Tucano which knocks up over 600W at full belt, too much really, but I figured that it should have enough beef to drag a dolly along on our smooth hard runway surface. I've actually gone down from 1250Kv on the Tucano to 1100 on this one to soften it a bit on a similar prop. I deliberately chose a tricycle lay-out because that naturally tracks straight and the only ground steering will be from the rudder, which might not be very effective. That choice restricts the front wheel size, although I could alter it I suppose to enlarge the rear ones. I can definitely take weight out of it and that will mostly be at the back, but front loading it with extra weight to help stability is definitely do-able if you think that will help. The idea of finning at the back to help keep it straight is another good idea, I'll do that. The other thing that I had thought about was another F1 practice, putting small negative incidence balsa winglets front and back to help keep it on the deck as it accelerates and the plane hopefully lifts away. I'll see what I can do with it, some careful ground runs will be essential to get it right, I'm sure. If it's hopeless I'll try a different approach. For practicality the plane needs to be hand- launch capable and I'm sure it will be, but I thought this approach could be safer for initial testing. if I was Nigel H I wouldn't be worrying, I know that he'd just chuck it without any qualms, but I lack that confidence and my reactions are a bit on the slow side! Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted October 12, 2014 Share Posted October 12, 2014 It seems you've got all the bases covered here Colin, one point I've not seen mentioned is the AOA of the aircraft on the dolly, you need to ensure it has a slight nose up attitude or take of runs may be quite long, however not to much or it may lift of the dolly without sufficient air speed to fly safely, about a degree to a degree and a half should be adequate Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 12, 2014 Author Share Posted October 12, 2014 Thanks Phil. I've set it to hold the plane at zero to the datum and the wing incidence is 1 degree. Quote Link to comment Share on other sites More sharing options...
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