Richard Harris Posted January 8, 2023 Share Posted January 8, 2023 I've had a few drone motors knocking around that I bought last year off FB market place for next to nothing and have been contemplating what to bolt them onto. I quite fancied doing another canard but this time go for a central fin rather than outboard as on my Uncanny design, this should make under arm launching possible and protect my fingers from the pusher prop. Shifty was drawn up over the Xmas break and I ended up with two plan forms, a canard and a delta version utiliising the same fuselage design To date my canard designs have used elevators on the forward wing for pitch control, to keep things simple I will try elevons on the main wing.and keep the canard fixed. I may need to mount the canard with a few degrees of positive incidence but hope to get away with reflex trimmed into the elevons.If it doesn't work I can always revert back to the tried and tested method. I've started building the canard version as it will be more testing than the delta, a few photos of what I have at the moment. Very simple using 6 and 3mm balsa sheet with a bit of ply for the bulk head, canopy is made using a pop bottle shrunk over a simple balsa mould the the first attempt is a bit naff. More to follow. Rich 1 Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted January 8, 2023 Share Posted January 8, 2023 That's a nice design..... Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted January 11, 2023 Share Posted January 11, 2023 Looks racy 👍 Steve Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted January 12, 2023 Author Share Posted January 12, 2023 I appreciate the comments gents, Thank you 👍 The airframe weight is around 160g bare but I can possibly shave a little more off with some fine sanding, servos and a few fittings have been ordered so when they arrive I can get on with it. Rich 1 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted January 16, 2023 Author Share Posted January 16, 2023 The electrics have now arrived from George at 4max. Going to try some of their heat shrink covering on the Shifty's, looks pretty similar to the HK stuff, has anyone tried it? Whilst I was waiting I have transfered my scribbles into electronic plans, I may alter the wing plan form on the delta version as I'm not quite sure yet. Photos are off the screen but you can make out the generic fuselage and the rough shapes. Rich Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted January 17, 2023 Share Posted January 17, 2023 happy new year Richard..looks really good design...well done. ken anderson...ne...1..RH fan club dept. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted January 27, 2023 Author Share Posted January 27, 2023 On 17/01/2023 at 10:15, ken anderson. said: happy new year Richard..looks really good design...well done. ken anderson...ne...1..RH fan club dept. Happy New Year Ken and thanks. In the middle of covering so will post some photos of the finished model when I'm done, I like this 4max covering! Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 3, 2023 Author Share Posted February 3, 2023 Covering is all but complete, I am pretty impressed with the 4max stuff and the way it has turned out. I will get on with the radio installation over the coming week and will probably make a small chuck glider to give me a good indication where the CG should lie. As it stands the CG is roughly on the LE of the rear wing which is near, I have a long battery bay that will give me plenty of wiggle room. A few snaps of where I am at. 2 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted February 3, 2023 Share Posted February 3, 2023 Superb! 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted February 3, 2023 Share Posted February 3, 2023 On 08/01/2023 at 16:22, Richard Harris said: ...Shifty was drawn up over the Xmas break and I ended up with two plan forms, a canard and a delta version utilising the same fuselage design To date my canard designs have used elevators on the forward wing for pitch control, to keep things simple I will try elevons on the main wing. and keep the canard fixed. I may need to mount the canard with a few degrees of positive incidence but hope to get away with reflex trimmed into the elevons.If it doesn't work I can always revert back to the tried and tested method.... In terms of minimising complexity I get this, but aren't you losing some of the main advantages of the canard planform by fixing the elevators? I'm sure it can be made to fly, but I can't help feeling pitch authority is going to be tricky to get right, kind of like a flying a conventional "tail at the back" planform with elevons. If it survives the early flights I'm sure it will be fine, but I'd be inclined to start with the elevator first, then once incidence angles and CG are set have a flight mode that switches it off. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 4, 2023 Author Share Posted February 4, 2023 Matt, I do agree with what you are saying regarding pitch authority, the fore plane is a good interference so if it doesn't work out in its fixed position I will remove and add an elevator. I am expecting to add some degree of reflex to the elevons, I will make a decision once I have experimented with a chuck glider. Rich 1 Quote Link to comment Share on other sites More sharing options...
Andy J Posted February 4, 2023 Share Posted February 4, 2023 On 03/02/2023 at 17:01, Richard Harris said: Covering is all but complete, I am pretty impressed with the 4max stuff and the way it has turned out. I will get on with the radio installation over the coming week and will probably make a small chuck glider to give me a good indication where the CG should lie. As it stands the CG is roughly on the LE of the rear wing which is near, I have a long battery bay that will give me plenty of wiggle room. A few snaps of where I am at. Very impressed by the quality of the covering. What technique do you use to cut out the compound curve trims? 1 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 4, 2023 Author Share Posted February 4, 2023 Andy, Nothing special, just mase up some paper templates then taped these to the covering before cutting out. These were applied with a lower heat setting on the iron, the 4max stuff is quite sticky. Quote Link to comment Share on other sites More sharing options...
Stuart Z Posted February 4, 2023 Share Posted February 4, 2023 Looks great S 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted February 5, 2023 Share Posted February 5, 2023 On 04/02/2023 at 14:19, Richard Harris said: Matt, I do agree with what you are saying regarding pitch authority, the fore plane is a good interference so if it doesn't work out in its fixed position I will remove and add an elevator. I am expecting to add some degree of reflex to the elevons, I will make a decision once I have experimented with a chuck glider. Rich It should be more efficient to add a smidgeon more incidence to the canard than putting significant reflex into the elevons. Even so, I suspect the challenge here is going to be getting this setup so that there aren’t significant pitch changes as speed varies. Hopefully I am wrong though! Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted February 6, 2023 Share Posted February 6, 2023 If it flys, like it looks it'll be a Gem. 👍 1 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 6, 2023 Author Share Posted February 6, 2023 (edited) 13 hours ago, MattyB said: It should be more efficient to add a smidgeon more incidence to the canard than putting significant reflex into the elevons. Even so, I suspect the challenge here is going to be getting this setup so that there aren’t significant pitch changes as speed varies. Hopefully I am wrong though! Your unnerving me Matt 😨, there's a nice slope by me, I will try some test glides first before committing to a prop! Edited February 6, 2023 by Richard Harris 1 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 26, 2023 Author Share Posted February 26, 2023 I braved the wind this morning and took Shifty out for a possible maiden. After a few test glides it was evident that it's CG needed shifting forwards. I managed to squeeze two 800 lmah 3s lipos in to the battery compartment which gave me an OKish glide. First flight was almost a loss as it was pitching violently up and down and my full throws were way too much, luckily I got it down in one piece. My pocket full of change was all I had for ballast so this was taped to the nose and throws were limited to around 5mm each way. Second flight was alot better but still pitch sensitive under full power. No real tendency to stall other than the canard starts nodding, slow speed handling is good. Rolls are axial and inverted was climbing slightly without any pitch input. Unfortunately my motor mount came loose so this will be modified along with some church roof strategically placed within the nose. Bizarrely there was no reflex needed and all trims were neutral, so the canard will be glued in the horizontal position. Here are a few photos, I did try and video the second flight, I will see what I captured and upload footage later on if its watchable. Chuffed. Rich 2 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 26, 2023 Author Share Posted February 26, 2023 Here is the footage of the second flight, not great as the sky is grey and its hard to track and fly. I will get some better video once the mods are complete. 2 Quote Link to comment Share on other sites More sharing options...
John T Posted February 27, 2023 Share Posted February 27, 2023 What a great looking model Rich. I've had a similar experience with the centre of gravity on a canard. A few years ago I knocked up an all sheet own design canard and used an online calculator to work out where the C of G should be. On the first flight the fact that I got it back on the ground in one piece had far more to do with luck than my piloting ability. I ended up moving the C of G forward by about an inch from the calculated position. This transformed it into a fast, aerobatic model with a surprisingly floaty glide that is now one of my favourite aircraft to fly. The C of G is now about 1/2" in front of the leading edge where it meets the fuselage. The wingspan is 34" to give that some scale. 2 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 27, 2023 Author Share Posted February 27, 2023 Nice looking canard John, I used this online calculator but my problem was that this is based on a plan view with straight edged flying surfaces, I also made a full sized depron glider which gave me a slightly forward CG of the calculated position so I went in between. Canard Center of Gravity Calculator (rcplanes.online) Mine lies about 50mm (ish) infront of the LE. One thing I did notice is that there was no obvious yaw waggling at speed that I get sometimes with my previous canards, I am guessing that the central top and bottom vertical fins (rather than tip fins) may have something to do with this? Rich Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted February 27, 2023 Share Posted February 27, 2023 Very nice Richard 👍 Quote Link to comment Share on other sites More sharing options...
John T Posted February 28, 2023 Share Posted February 28, 2023 17 hours ago, Richard Harris said: One thing I did notice is that there was no obvious yaw waggling at speed that I get sometimes with my previous canards, I am guessing that the central top and bottom vertical fins (rather than tip fins) may have something to do with this? Now you come to mention it this model does occasionally give a bit of a tail wag, particularly after a high speed turn. I'd not really given it much thought before. I'm not quite sure what aerodynamic effect would cause this. Possibly there are tip vortices from the fore plane interacting with the tip fins? As the wings are swept back I stuck the fins on the wingtips in order to get them as far back as possible, but perhaps a larger central fin would be ok. If nothing else it would make it less prone to "hanger rash" when moving it about. Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted February 28, 2023 Share Posted February 28, 2023 Either of those would make a nice plan in the mag....... Quote Link to comment Share on other sites More sharing options...
Bruce Collinson Posted February 28, 2023 Share Posted February 28, 2023 There might be one coming soon … Quote Link to comment Share on other sites More sharing options...
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