Ton van Munsteren Posted December 3, 2013 Share Posted December 3, 2013 Danny, Don't ever post that link again I just got so many new ideas of all the other great Pipers. If I only had good 3views for all those lovely Pipers. And yes Iam 100% sure, that there will be a plan of the Apache, but first lets fly this one and than we will see. Ton Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 3, 2013 Author Share Posted December 3, 2013 Oooops sorry I am sure there is a DeHavilland family tree somewhere shall I post a link to that? Anyway have made an error on the nacelles, due to brain fade I glued the retract mount bulkheads in place, stupid idea, you cannot fit the nacelle to the wing if you do that. Anyway gave me an opportunity to test medium CA and lite ply..... answer I couldn't break the joint. I ended up sawing the winglets of the bulkheads off. Once finished I will add them back on again. Thats what I get for not reading the instructions..... oh yes we are making it up as we go along Here are the nacelles excuse the backdrop, needs to be moved on to a clean section. I will sort that before I take wing pics later wanders back to the bench humming "The Stranger" Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 3, 2013 Author Share Posted December 3, 2013 Ooo sorry Ton, yes I received the modded drawing for the nacelle "ribs" Cheers Danny Quote Link to comment Share on other sites More sharing options...
Martin Roberts Posted December 3, 2013 Share Posted December 3, 2013 Hi Danny, oops again, you are absolutely correct, I got myself muddled on the naming - yes the AZTEC was the later version or child in the family tree.... we all make mistakes sometimes ... maybe I should have read the instructions LOL...By the way in another family tree...on my wife's side they are all Piper's and one just has to get one's head around the names vs dates for that lot too Marty Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 3, 2013 Author Share Posted December 3, 2013 wing panels have been seperated, and what a beautiful fit. The tubes are absoluteley parallel thanks to the CAD work, and slide to a perfectly sealed edge. ooo "F.B.I." Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 3, 2013 Author Share Posted December 3, 2013 Hi Marty, the ooops key is worn out on my keyboard so I wouldn't worry about it. There is a chap at my club that swears that this is an AZTEC I keep saying it isn't, maybe I should take that Wikipedia print out in for him to see Cheers Danny Quote Link to comment Share on other sites More sharing options...
fly-navy Posted December 4, 2013 Share Posted December 4, 2013 Ah Mr F what a thoroughly enjoyable hour I have had reading this,another Lichfield masterpiece,my love of Piper a/c you well know,are there plans to be available soon and is this the one to bring me over to the "Light side" with yourself and Mr B. Stunning work as usual Danny Quote Link to comment Share on other sites More sharing options...
Martin Roberts Posted December 4, 2013 Share Posted December 4, 2013 Hi Ton and Danny, I am just thinking to self (and you as well), I do like Heritage color schemes, so how about this one - of course I would have to carefully consider accuracy when it comes to the flag And someone will obviously want to do this scheme - including the fourth wheel for Carrier training on the tarmac LOL Marty Quote Link to comment Share on other sites More sharing options...
Martian Posted December 4, 2013 Share Posted December 4, 2013 Wonderful work Danny and Ton of course. as a matter of interest how long are those phenolic tubes and how long is the outer wing panel and what is the estimated weight of the panel ,sorry lots of questions Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 4, 2013 Author Share Posted December 4, 2013 Hi John, long time no speak. I have heard rumours that the magazine may well be interested, but at 1/6 scale the size may make things difficult. We will see. However Rob Bulk of RBC (who cut this for us) will be offering a kit of parts at a future date. Have to see if it flies first Ton is frantically converting the cad drawings into a workable 2D version as we build. Hi Marty, I do like the original Piper colour scheme, loads of character. Beware this is the 4 seat variant not the six seater you have shown in your first pic Not sure if the fus is longer for that one. It certainly has the re-arranged window layout. The military version is a great scheme if you want to fly a civvy at warbird events You all may be able to help us here, it is a real shed load of work to re-design the fus for the wing to be removable. If you were to consider building this model would you prefer to do as I have and have the centre section of the wing complete with nacelles, permanently attached to the fus? or would you have the centre section removable and no removable outer wing sections? Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 4, 2013 Author Share Posted December 4, 2013 Hi Martian, and thanks, the tubes are 125mm long and really lovely quality, light but rigid. I have no idea of the eventual weight of the model never mind a panel I am afraid, we will have to see. The outer panel is about 19" inches span, nearly a quarter of that wing tip The 4 ribs involved in the load transferal are 3mm lite ply, I am not sure where Rob gets the lite ply as it is much nicer than I have seen available in the UK. Its a pale white as opposed to brown, with a very fine grain. Possibly a birch laminate?? Cheers Danny Quote Link to comment Share on other sites More sharing options...
chris larkins Posted December 4, 2013 Share Posted December 4, 2013 Keep the centre section attached, then it can sit on its wheels for storage. Quote Link to comment Share on other sites More sharing options...
Pat (rActive) Harbord Posted December 4, 2013 Share Posted December 4, 2013 Danny/Ton awesome design and build. Lovely to see a twin civ project huge ask now ... Would you be prepared to share the 3D model? Purely for my own educational purposes. I'm learning AutoCAD via online videos but failing to make the leap to what I want to do - design model aircraft. I'm hoping deconstructing an existing expertly drawn file will help my understanding. totaly understand if its a no, just though it would be worth asking Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted December 4, 2013 Share Posted December 4, 2013 On the wing being removable Danny, I see two problems with building it attached. 1) There only seem to be very small hatches for access to a cavernous fuselage. If the wing came off, access to radio, wiring, ESC's etc would be much easier. 2) With the wing staying attached, it looks like it's quite a lump to store. If you have the perfect spot to keep it, then great. Otherwise a fully removable wing gives you more options. Just my twoppence worth Looks a fine model, which ever way. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 5, 2013 Author Share Posted December 5, 2013 Thanks guys, I think the camps are split. I am with Chris though I think a removable wing would give great access to the radio installation for both installation and servicing. But it will still work through a hatch I am sure, its just a wee bit tight I like the idea of transporting the model on its wheels, though storage may not be so easy with the wing attached? Anyway keep the ideas coming on that one please? This evenings progress was slow, it was a case of more head scratching. The first bit was simples, I sheeted both of the outer wing panels. I decided on the lower sheeting for now. Once the servos are fitted then this can be closed up. Then I thought I would wrestle an aileron into submission.... Then it was time to scratch my head.... this went on for some time....... The problem is the hinge point is 3mm below and about 20mm behind the aileron leading edge. Now I understand how to do this, but not how to do it so you can replicate it for 6 hinges. Anyway a mockup was made.... This then gave me the angles I needed to make this jig.... A section of hardwood is placed in the channel, flat aginst the bottom, the pillar drill can then drill a perpendicular hole. Once the channel is removed the engle required when the block is abutted against the rear spar should be correct (where's the fingers crossed emoticon when you need it?) Its a little late to fire up the pillar drill now, so it will have to wait tomorrow evenings session..... It being after midnight it seems only fitting to leave you humming "midnight" Cheers Danny Quote Link to comment Share on other sites More sharing options...
Martin Roberts Posted December 5, 2013 Share Posted December 5, 2013 Hi Danny and Ton, just regarding a second prototype and the question of a removable one piece wing. I agree that it is a fair amount of re-work and basically a completely new centre of fus and wing sections to be designed and constructed, however as has been stated by Chris Bott, the fuselage of this aircraft is large to say the least so one has to really consider whether this will be a model to construct if the wing centre is to remain fixed in situ.... The upside is that the model is more structurally sound in its present design with the removable outboard sections, as well as the easy repair of a wing tip, the downside is the fiddling with the two connections and locking the tips on. The upside of a one piece wing of course is the simple connection of wiring, ample space for fiddling with servo's (elevator and rudder), and far easier repairs if a wing is damaged in a major way, and of course the storage and the transport, the downside is very small, and would also allow for easier conversion to a fuelled version and even the addition of air retracts - there is of course ample room for this within the fus.... More modellers would, in my opinion, decide to go forth and join the Piper Clan with a removable wing. WWII twins would really benefit from Tons design, as they generally get thrown flown around with a lot more aggression, now I have to start rejigging the Canberra I started drawning...LOL Marty Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted December 5, 2013 Share Posted December 5, 2013 Martin, my thoughts actually included the removable wing, AND removable tips. This is what I have with my DH88. That has the centre section attached most of the time, although that is a fair bit narrower than this one as the joint is right at the outside edge of the nacelles and the nacelles are closer together. So mine travels on it's wheels, is stored with the centre section in place, but the whole wing comes off for any access to all the workings. Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted December 6, 2013 Share Posted December 6, 2013 Hi Danny, as you asked me earlier to stop you in case you are running deep into scale details - just one question. Why is the hinge point 20mm behind? if you change the radius of the end of the aileron to a smaller one the hinge point would come much closer. As it is a hidden gap anyway - nobody would see it as long as you do not take the aileron out of the model. I am not sure if the robart hinge on a alu tube is a robust solution. Also: the further back the hinge is the more you have the need of a slot for the wing-part of the hinge - and it may become visible - depending on the maximum throw of your aileron. see second picture - at full throw the hinge slot becomes visible. ok, this is an Extra, so the throw may be a bit more than on your Apache. how will you do the end of the wing - you have to do a concave shape - as it is shown on the wing. How will you cover it? Wouldn't it be easier to mill a concave shape into a piece of balsa and use that instead? (see example) VA Edited By Vecchio Austriaco on 06/12/2013 08:11:33 Edited By Vecchio Austriaco on 06/12/2013 08:12:53 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 6, 2013 Author Share Posted December 6, 2013 Hi VA and thanks for the comments. The Apache is a little odd in respect to the hinges on the control surfaces, they are not concealed and the surface leading edge radius is not round but radiused to the hinge point. I guess as a result of the hinge points being where they are. These hinge points are presumably to give differentlial on the surfaces like the ailerons, but not sure why for the flaps I would rather get the control surfaces the right shape and hinged correctly than make them too simple. There isn't that much difference in the amount of work, once you have decided the angles. I have always wanted to tackle external hinges like this so its a good oportunity to practice. As for strength, we will have to see, the ailerons are only 345mm long and I am going to use 3 hinge points, mounted in bass wood blocks. Lets see if there is any flex when one side is all made up. I could always fill the tube with gorilla glue but thanks for your thoughts on this. The wing tips on this are enormous and would cost me a fortune in balsa. They are not concave though different versions of tip are to be found. Mine has a fairly simple shape and will be made using blue foam, and be glassed. Thanks for keeping an eye on me VA Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 6, 2013 Author Share Posted December 6, 2013 This shot shows the lower hinge point and my cad version of the aileron arrangement Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 6, 2013 Author Share Posted December 6, 2013 The jig wasn't as succesful as I hoped though it did get the holes very close, some fine tuning of each block was necessary to get them spot on. The blocks holding the alloy tubing are basswood and bonded to the rear spar. Should be okay this isn't a high performance aircraft after all Cheers Danny Quote Link to comment Share on other sites More sharing options...
Nick Russell Posted December 6, 2013 Share Posted December 6, 2013 Hi Danny, Bit of a new boy around here so hope no one minds if I chip in a bit. The design of the aileron is known as a differential frize aileron. The purpose is to reduce as much as possible the adverse yaw caused by the ailerons. Differential in that the up going aileron goes up more than the down going goes down so that the up going aileron reduces the lift on the inside inside wing and increases the profile drag, while the down going aileron gives a smaller (compared to the reduction in lift on the inside wing) increase in lift, and therefore an increase in induced drag. The frize part is a further increase in profile drag caused by the leading edge of the aileron on the inside wing (the up going aileron) projecting into the high pressure air under the wing and directing some it onto the top surface of the aileron. The flaps are slotted flaps so that when retracted they are tight up against the wing but when lowered air is forced through the slot (and accelerated) so that the energised air 'sticks' to the upper surface of the flap. Produces lots of drag along the span of the flap which is why they are so long and narrow. Must say how impressed I am with the speed of your work and also the quality of the workmanship. Truely inspirational! Nick. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 7, 2013 Author Share Posted December 7, 2013 Hi Nick, welcome to the forum and glad you could join in. Thanks for the info, I knew about the ailerons but wasn't aware the slot effect increased the drag, thanks for that They are proving a bit fiddly, and not as easy as a mylar strip down the centre of the trailing edge, but they look better in my opinion. Nothing new to show this evening I am afraid Went to a carol concert instead Cheers Danny Quote Link to comment Share on other sites More sharing options...
Martin Roberts Posted December 7, 2013 Share Posted December 7, 2013 Hi Danny, firstly a big thank you to Nick for the information, another point for the ailerons being so 'awkwardly' hinged is that although this aircraft had a 'never exceed speed of 240 knots', that is still quite fast. I am not sure at what speed control surface buffeting cuts in but having the pivot point so far back would probably offset any induced buffeting by way of counter balance (amount of aileron in front of the pivot point) also counter by a balance of the air pressure on the forward area of the surface...now readers please don't mistake what I am saying here for the sort of buffeting from a higher performance military craft, this aircraft was an at the time high performance civilian commuter, so any buffeting from the ailerons that could cause discomfort to a passenger would have been designed out, especially when the other benefits as identified by Nick also come into play, of course the last part which would have been carefully considered by the designer is that the force needed to be exerted on the control surface by the pilot is also further reduced by the balance of air pressure on the surface which would make it more comfortable for the pilot as well. As far as my tuppence goes, I probably would have designed the 'hinge' as 'a single rod running through the aileron with a z bend to (the appropriate center point that you calculated) a bearing fixed into a cleat each end, a cleat similar to a control horn soldered midway to the rod would be located to a bearing soldered onto a rod located similar to the detail in the photo (above) for the flap ... ok so the detail would not be perfect but far simpler to model and the same outcome as your design and the rod passing through the aileron would stop any warping of the aileron.. Back to you Danny Marty Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted December 7, 2013 Share Posted December 7, 2013 Actually Danny I don't think Nick was simply saying that 'the slot effect increased the drag'. The slot caused by the offset hinge allows air to bleed from the lower surface of the wing through the slot to re-energise the airflow over the top surface of the flap. The airflow therefore 'sticks' to the upper surface for longer, (than would be the case with a plain flap), before breaking away and becoming turbulent. The effective camber of the wing is increased and the lift enhanced by having the slot. Consequently lower take off and approach speeds will be possible when slotted flaps rather than plain (or split flaps) are fitted due to the lower stalling speeds. You don't get something for nothing however and slots, weather leading edge or trailing edge slotted flaps, will increase drag too. Small deflections of flap increase lift mostly with a small increase in drag. At large deflections of flap there is a significant increase in drag with a modest further increase in lift. You probably know all this anyway. I love this build blog. Someone said 'a master class', I can't agree more. Great workmanship Danny. Quote Link to comment Share on other sites More sharing options...
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