Cuban8 Posted October 28, 2023 Share Posted October 28, 2023 2 hours ago, toto said: It's the first time I have heard of the term shear webs. Learn something new every day. Maybe I'll come across the real thing in some of my other kits. I'll keep my eye open. Cheers Toto Many variations on a theme to look out for. I can't remember which one without finding the plan, but one of my aerobatic models has what you might call a graduated shear web structure, where the first third of the wing spar from the root is webbed with 1/16 ply - the middle third uses 1/16 balsa and the final third dispenses with any webbing at all. This type of contruction can be surprisingly robust, as one will find when scrapping a model for whatever reason, and an old scrap wing needs to be broken up. Very nice and tidy build, by the way. 1 Quote Link to comment Share on other sites More sharing options...
toto Posted October 28, 2023 Author Share Posted October 28, 2023 Hi Cuban8, Thanks for the above. I'm sure as you say I will come across numerous variations of the same. You can usually guess when you look at the various elements and try and envisage them as part of the bigger envelope whether or not they instill confidence in the overall strength. If not .... start looking for any small add ons that you can to strengthen up weak areas without adding too much to the overall weight. Small gussets, strengthened etc. Hope you enjoy the rest of the build. Toto Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted October 28, 2023 Share Posted October 28, 2023 The reason for shear webs, or in this case, a full depth spar, is to form a closed box section or tube. Aeronautical structures, once you get past the all wood early aeroplanes was to provide the torsional stiffness without resorting to external bracing. If you look at all aeronautical structures they are based on closed tubes. This gives both bending and torsional strength from very light structures. Consider rolling a piece of paper into a tube and sellotaping it together along the length. A sheet of paper has no torsional rigidity and appears to have little chance of carrying any weight. However a paper tube is a very different animal. It has both bending and torsional strength. The D box formed by the full depth spar, or alternatively shear webs, together with the wing skins and leading edge, form a closed tube giving the wing great torsional stiffness. Without the shear webs, and without a fully sheeted wing, the structure is easy to twist. So, as you deflect the aileron it would twist the wing and negate the aileron's effect. Structures lesson 1 from aeronautics. This is also called a stressed skin or monocoque construction. 1 Quote Link to comment Share on other sites More sharing options...
toto Posted October 29, 2023 Author Share Posted October 29, 2023 Very interesting Peter. Sort of makes sense. Toto Quote Link to comment Share on other sites More sharing options...
toto Posted October 29, 2023 Author Share Posted October 29, 2023 So .... the morning after the night before .... had a couple of beers last night so just getting myself together before hitting the shed. I'll be picking up on the wing construction and will hopefully make some progress. I have had a bit of a rethink on how to power this. Currently I have a force 46 sitting upfront .... but .....given the likely route of my currently proposed flying progress ( using electric to mitigate the unnecessary additional learning curve of setting up glow engines ) I am considering installing an electric motor and ESC. Some may say that I'm a bit indecisive ....... but I'm not so sure. feel free to weigh in. See you in the shed. Toto 1 Quote Link to comment Share on other sites More sharing options...
PDB Posted October 29, 2023 Share Posted October 29, 2023 What worked for me was choosing what my tutor was most experienced and comfortable with. 👍 2 Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted October 29, 2023 Share Posted October 29, 2023 Toto It is certainly true that going electric means that you just plug in the battery and go, On the other hand, you need to buy your fuel up front i.e. the packs, which can mean either you spend a lot of money or you need to have in-field charging and two or three packs. With glow motors, once you have learned how to start and tune them then you just need to refuel and go, always assuming that your Rx pack has the capacity or else you just carry two with you. I could get through 6 flights a day with my IC powered Wot 4 with no problem of Rx battery capacity and that was a 4 cell NiMh of 1,100 mAh. In truth, provided you have someone who knows how to start and adjust a glow engine there is little that needs fiddling with. You just need to choke it the required number of turns, check it's not flooded by turning it over, apply the glow start and then the starter. In fact, I sometimes dispense with the starter and use the chicken stick to tap the prop in the reverse rotation direction and the engine then fires and runs the right way. When it's a cold day then an electric starter can give an instant start but once it's run once then the engine will be happy to start on the reverse flick as I described. Provided you have set up the plumbing correctly, you just add fuel and fly. This is now almost as simple as connecting the battery to an electric motor. OTOH, you don't need to extend any tender loving care on an electric motor when you have finished flying or clean down the model - unless you have a load of mud on the underside of the wing caused by the wheels! Running a glow up to operating temp until the tank supply is exhausted is a good way of looking after the engine without any after nun oil being necessary. Of course, empty the tank first and then put a couple of turns of the hand pump to add just enough fuel for this procedure! When I was practising for my B, I could fly 2 full B schedules on one tank full. You may find that being able to fly 2 A schedules per flight once you get to that stage would also be helpful in speeding up your learning curve. 2 Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted October 29, 2023 Share Posted October 29, 2023 2 hours ago, toto said: Very interesting Peter. Sort of makes sense. Toto Hi Toto It more than makes sense as that is how full size aeronautical engineering works. It's the same for today's cars that don't have a separate chassis. Which is why when you make a convertible you have to add extra structure to make up for the strength and rigidity lost by not having a roof. Think of how much weight a round drinking straw can support compared with a drinking straw squashed flat will. Quote Link to comment Share on other sites More sharing options...
Outrunner Posted October 29, 2023 Share Posted October 29, 2023 Electric every time, no messing about fueling, starting, dead sticks, cleaning the mess off afterwards, no noise. Just plug and go. Yes you do have to invest in some battery packs up front but when you get to the field just plug in a battery and fly, no tuning and fiddling required. Ok so I'm biased I sold all my glow engines years ago and never regretted it. 3 Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted October 29, 2023 Share Posted October 29, 2023 (edited) Please let's not let this thread degenerate into an ic vs electric 'bashing' session. Personally, I fly both quite happily....... @toto talk to your new mentor. Edited October 29, 2023 by GrumpyGnome 3 Quote Link to comment Share on other sites More sharing options...
toto Posted October 29, 2023 Author Share Posted October 29, 2023 Hi Grumpy, I did yesterday and we decided to start with the Domino as its electric with no fuss over starting to leran IC immediately. I have plenty batteries .... in the case of the Domino x 4 ... 4s 5000 mah and 4 x ...4s 3250 mah that can all be used. He did say to bring the Arising star down as well and he would have a look at it so IC is not being comp.etely discounted..... just on the back burner whilst I get some more straight forward stick time. Anyway as suggested .... let's not turn the thread into something else ....... even though I did start the rabbit running ..... apologies. I think I will go ahead with the electric conversion from the viewpoint that I will hopefully get quicker use from the model on completion. Again apologies for wandering Toto 2 Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted October 29, 2023 Share Posted October 29, 2023 Your thread.... some wandering is allowed. 8 batteries is plenty. Keep them warm in the cold weather for optimum performance. 1 Quote Link to comment Share on other sites More sharing options...
aidan mcatamney Posted October 29, 2023 Share Posted October 29, 2023 I love both. Electric and IC. 2 Quote Link to comment Share on other sites More sharing options...
David Davis Posted October 29, 2023 Share Posted October 29, 2023 3 hours ago, Outrunner said: Electric every time, no messing about fueling, starting, dead sticks, cleaning the mess off afterwards, no noise. Just plug and go. Yes you do have to invest in some battery packs up front but when you get to the field just plug in a battery and fly, no tuning and fiddling required. Ok so I'm biased I sold all my glow engines years ago and never regretted it. That's funny. I only have one electric powered model and I don't fly it very much! 😏 Quote Link to comment Share on other sites More sharing options...
Outrunner Posted October 29, 2023 Share Posted October 29, 2023 1 hour ago, David Davis said: That's funny. I only have one electric powered model and I don't fly it very much! 😏 That's your choice. If people prefer to fly IC then that's fine. The only thing I object to is noisy models. Quote Link to comment Share on other sites More sharing options...
David Davis Posted October 29, 2023 Share Posted October 29, 2023 9 minutes ago, Outrunner said: That's your choice. If people prefer to fly IC then that's fine. The only thing I object to is noisy models. So do I. 1 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted October 30, 2023 Share Posted October 30, 2023 20 hours ago, toto said: I think I will go ahead with the electric conversion Your model, your choice, no wrong answer here. Quote Link to comment Share on other sites More sharing options...
toto Posted October 30, 2023 Author Share Posted October 30, 2023 OK .... back in the shed and its confession time ...... We are on Part 32 ..... and I have mis-interpreted it. .... yes ..... I am selling you a dummy. I previously said that this stage was to install the trailing edge ..... the destructions call for the bottom spar ....... which I fitted in error back in Part 28. Part 28 .... called ONLY for the top spar to be fitted ..... I fitted the top and bottom spars. The pencil points to the previously fitted top spar ...... ( the wing is currently upside down ). This is the bottom spar ....... and again. So in summary ..... Part 32 is in fact complete. Now .... on to Part 33 which asks us to trim off the " jig tabs " with a knife ..... and here is what they are talking about so .... I'll be back once done ... toto 1 Quote Link to comment Share on other sites More sharing options...
Bob Burton Posted October 30, 2023 Share Posted October 30, 2023 23 minutes ago, toto said: the destructions call for the bottom spar So when are you supposed to fit the webbing between the top and bottom spars as you obviously can't fit it without both of them being present ? Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 30, 2023 Share Posted October 30, 2023 5 minutes ago, Bob Burton said: So when are you supposed to fit the webbing between the top and bottom spars as you obviously can't fit it without both of them being present ? Full depth spar as well, no webbing. Quote Link to comment Share on other sites More sharing options...
toto Posted October 30, 2023 Author Share Posted October 30, 2023 (edited) OK .... all the jig tabs are removed and a sanding just to straighten things out ..... Part 33 is now complete. Part 34 .... is where we start to cover the underside of the wing .... be careful not to jump too far ahead here ..... you will see why in the next step .... So I laid the 1.5mm balsa stock sheets along the edge of the central spar and clamped it down .... Then I up ended the whole thing and cut along the leading edge to a rough size ..... using the edge above as a guide ........ and you get this ......... I then removed the sheeting and applied aliphatic glue along the main spar and along all the other surfaces that the sheet balsa would be adhering to ..... and pinned and taped it all down to set. and another ....... Part 34 .... complete. Please note ***************** The illustration for the last part ( Part 34 ) shows the two lower end balsa sheet parts for some reason ...... these are NOT fitted at this time .... to me ... this is just confusion. Please feel free to look them out BUT DO NOT GLUE YET. And here is why ..... Part 35 ....... two doofers ...... parts W15 and W16 need to go in here as shown ..... these are handed so be careful as to where you install them. W16 has a notch out of one corner which should meet on th top corner sitting against Wing spar W3. The slot in the cornet is to take the spar capping which is fitted later. W15 goes between wing spars W1 and W2 ..... again ..... Please note that this piece is not symetrical and actually goes according to the Dihedral of the wing so take care .... Once these are "Dry Fitted " ....... check that the wing joiner bar fits in along the two rectangular slots BEFORE gluing W15 and W16 permanently into place ..... Take the wing joiner back out and glue W15 and W16 permanently. Do not glue the wing joiner for now. Part 35 is now complete .... Part 36 ...... Now that we sure that the wing joiner is going to fit as required ..... we can move onto Part 36 ... which is to glue into position the under wing sheeting to cover the first two wing ribs between the main spar and the inner trailing edge as shown in the illustration in the destructions ...... I'm off to look out the balsa and will be back .... toto Edited October 30, 2023 by toto Quote Link to comment Share on other sites More sharing options...
toto Posted October 30, 2023 Author Share Posted October 30, 2023 So ..... the two precut balsa sections provided in the kit are trial fitted .... and the first of them is glued in place now ..... be aware ..... the bottom piece .... still to be fitted ......the inside edge aligns with a cut out along the length of the bottom trailing edge .... so you have to line up this to get the inside edge of the upper section as fitted below ...... I forgot to photograph this but you will see what I mean when you come to do it. It lets the sheet bed down into its proper position nicely..... just take your time here .... apologies for missing the photo. then the bottom ..... which I have cut to size. with a bit trailing over the root end still to be trimmed when dried ..... and plenty masking tape to hold it down a bit. You could use more pins but theses wing spars are a bit thin so there is a real chance they could split .... and another ........ then add about two ton of weight to help it along its way. Part 36 is now complete ..... Part 37 ..... We now move onto the fitting of the servos tray W18 and the doubler W17 .... I'll be back ... toto Quote Link to comment Share on other sites More sharing options...
toto Posted October 30, 2023 Author Share Posted October 30, 2023 OK ..... so we have the wing servo tray and doubler ..... W17 and W18 ... cut out and ready for laminating together ..... so on with the glue ..... and sandwich them together making sure the inner aperture of both line up accordingly ..... then add a couple of clamps and set aside for drying ..... This part calls for the servo tray to be glued into position within the recesses between wing ribs W3 and W4 with W17 being on the underside or inside face. This can't be done right now as I am awaiting the parts to dry ...... so ....... it seems like a good point to stop for the night. Tomorrow .... I'll finish this part off and start applying the cap strips along the other wing spars. cheers for now .... toto Quote Link to comment Share on other sites More sharing options...
toto Posted October 30, 2023 Author Share Posted October 30, 2023 One more small thing worth mentioning whilst I remember ....... I was very nearly soiling myself earlier when I saw this ..... see the depth between the forward balsa sheeting and the wing rib ....... I thought I had screwed up ..... same both sides ....... here is the next rib ....... you can see the finished edge of the rib sits higher ...... about a balsa sheet from the top ....... don't wet yourself ..... its meant as the two lower rib heights are to accomodate the thicker " ply " servo section. ... no mistake made ..... I was thinking .... packers and all sorts of black magic ..... phew .... instant relief .... and no change of underwear. thats me for tonight .... toto 1 Quote Link to comment Share on other sites More sharing options...
toto Posted October 30, 2023 Author Share Posted October 30, 2023 OK ..... couldn't resist it ..... one more shot... and .... I know .... that was two ..... I'm outta here .... toto 2 Quote Link to comment Share on other sites More sharing options...
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