A channel dedicated to scale aero-modelling, and more specifically detailing. I show various skills that are used to create the illusion of a full scale aircraft but in a scaled down radio controlled flying model. Unlike most modelling where weight is not an issue, and you can use whatever materials you like. With aero-modelling the mantra is "weight" and how can I save adding extra weight. So we have to strike a difficult balance between adding realism and saving weight.
level is through your datum. Most models fly straight and level with a little positive incidence on the wing. but that depends on the wing section. so not a straightforward answer for all types. On the Chipmunk for example, the datum is parallel to the canopy rails.
I thought I had replied to your suggestion but it seems to have vanished, sorry about that. Yes nylon bolts might work, as would smaller wood screws. the thing you dont want is the long coming off completely and going through the bottom of the wing. Lots of ways to skin a can so to speak..... but thanks for your thoughts, they are very valid.
Does the plaster get hot enough to melt the plastic or make it softer? Would multiple pours solve that problem? I'd be tempted to use spray foam to add more support to the plastic so it's not just supported by the rim. Would that help?
No the Herculite doesn't get hot enough to do any harm to the plastic. Modellers do build a box around the outside of the stand and back fill with sand to help support the weight. The weight of this one was okay to just be supported by the edge. I do say in the video that the distortion was actually in the original vac-formed canopy......
I for one don´t like to waste on the materials when I do a cast like that. I carve a piece of foam that leaves around 1-2 cm all around. I put a big weight on top of it to make it stay submerged before filling around it with plaster. It has one more advantage as it makes the plug lighter to handle....
You are quite right, however in practice the entire structure needs added rigidity to keep the foam submerged, and the setting times mean that you have to act quite fast. But in theory you are right. In my defence 5kg of Herculite is just £11 so you have to balance cost versus time. But a bigger plug, I would definitely think of adding cheaper ie foam packing.
Great attention to detail. It reminded me of a series on You tube of a great American scale model builder Don Rice (sadly now passed away). He showcased a series of him building an F4U Vought Corsair. He like you went to great lengths in building his Corsair from originally a commercial kit. There was a section on him making a mould and forming numerous canopies to get the perfect result. I enjoy your series immensely, so keep up the good work. Off to Weston Park now to see more fabulous models.
Thankyou, and glad you are enjoying my antics. I followed Don, the canopy saga was epic. I remember one session where he mixed a bucket of casting powder and water, much as I did here, only I think Don was a but over exuberant when mixing and the whole lot ended up everywhere in his shop. His antics were fantastic to watch, clever, tenacious, and funny. Great guy, very sadly missed.....
@@cammnut Then the next thing I would try would be to use plastic that is about 20% to 30% larger in area. That will give more plastic to stretch over the plug. After viewing the vid the second time I think that is what I would do. I have done some limited vac forming in my modeling career but never at this scale.
Yeah it's the Scale of this and the thickness which is proving hard. I get 4 sheets out of a full petg sheet, the full sheet is £50 if I make the pieces I use bigger, I can only get two out of each full sheet, which effectively doubles the material costs. My table, heater box, and frame would all need remaking. So it's not going to happen. I will let the professionals do it. My A4 vacforming has worked fine, so the process works, just not cost effective for one off molds like this. But thx for your thoughts.
A couple more suggestions to help make a succesful canopy moulding. Both require a good deal more work. Most if not all of the commercial small scale vac forming machines have the plastic held in a rigid frame over the body of the machine. The heater is located above the plastric sheet and then the mould is pushed up into the plastic sheet. Once the bed of the machine is sealed underneath the plastic sheet the vacuum is turned on to complete the moulding cycle and the heat is removed. Have a look for machines made by C R Clarke. Another suggestion and a very great deal more work, is to make a female mould. I've used this technique, the advantage is that you can get a good deal of very crisp detail into the moulding and it seems that it is a more reliable method. The cost of course is the amouint of work needed to make the mould.
Hi, the deep heater box is to even out the heat, a buffer, this was learned from watching several vac form videos. A different (hotter) element might work. But I have sent the plug away for forming.
Thanks for sharing this project with us. I personally really appreciate it since I will attempting something similar later this year. Points I would make, for the future, if I may, (having watched quite a few other video on broadly this subject), and as others have said. In no particular order: 1) maybe a larger sheet, 2) much stiffer/stronger frame, 3) make sure the sheet is thoroughly warmed/heated and absolutely all over, 4) One design I saw was laid out as the following a) a heater box on the left, b) the mould on the right, c) and the frame in the middle hinged so that it could first be position over the heater, and then hinged over the mould - so you don't have to be distracted by considering positioning the hot sheet. 5) Think about how much heat the sheet is losing while you're trying to heat it evenly. It's A LOT. Perhaps consider another radiant heat source from above (later, to hinge out of the way) at the same time as from below. NOT trying to teach you how to suck eggs etc., but the above are definitely things I will look at before my attempts. One other thing depending what you decide on from the above, maybe a frame requiring only one pressure point, so that once the heated sheet is in place, all you have to do is apply pressure at that point. This frame might look like say 4 pieces of 40mm equal angle iron positioned towards (but not at) the ends each of the long sides, and coming together at a central point high enough to clear the mould. Perhaps a long-ish hinged lever (4 x 2 timber) could be used to apply the pressure. I realise that it's a lot of set up for such a short lived part of a build, but who knows, you might become so capable that people will be sending theirs mould to YOU to finish for them! Incidentally, and if I may again, how much will the professional moulding cost? Thanks again for sharing with us Regards Mark in the UK p.s. sorry the above was so long winded.
Thanks for your thoughts, lots of good ideas in that lot. A larger sheet size would probably work, but the ramifications of going bigger are too costly, new heater box, new vac table, sheet price doubling. The cost of having the canopy formed is very cheap by comparison...
Thanks for these Danny .Very informative couple of videos. It's amazing how much time in this hobby is spent not quite getting there. ( Don't ask about the multitude of half finished airframes in my loft...One day ) And yet still the satisfaction is in the trying. I had a similar biopsy last year and it's surprising how quickly the face heals. Hope all is well. I'm sure it will be Take care.
Only halfway through watching this video, and thinking if it is possible to carry the plug with the vacuum attached to the heating oven and placing it on top of the sagging plastic, use the heat of the over to assist. You may need a larger sheet and a stiffer frame to hold it
Unfortunately the plug would not survive the excessive heat. But a similar idea had drifted through my noggin, resting the uturned plug in the heated plastic and let gravity take over. Anyway its on its way to a proper vacuum forming company now, lets see how it comes out.
You remind me of me😂, I’ve had many a desperate moment trying to do similar things, but your restrained response put me in awe, mine would definitely not be broadcastable 😂
LOL you had me chuckling. None of this is life or death! and its all fun. When it works its great when it doesn't everybody says I told you so, such is life. You really mustn't let it get to you. But I do utter the odd curse when the cameras are off, just knocked over a tub of 500 m4 nuts....... there were expletives.... ;)
Hi Septic , the first one (bubbles) is caused by moisture on the plastic. Put your pre cut sheetstock , in the airing cupboard , overnight We often leave a first pull ,on the plug , wet sand it with 1200 , voila, crystal clear !! Cheers mate Phil
Thanks Walter, in this case too much heat, the two you see in the closing shot were from the same batch, just not heated for so long. If you leave the protective film in place it's harder to judge the droop, and I over did the cooking! Slowly bringing the temp up should dry any moisture too.
Not sure about PTG but many vac forming plastics need a temperature in the range 140- 160 c to form easily. It is probably a good idea to warm your mould as well because the plastic in cont act with a cold mould chills remarkably quickly. It looks too that your frame holding the plastic needs re-designing to make it stiffer but even then I suspect withn the very small margin of plastic around the frame you will still have problems. Good luck but an excellent video
Thank you, results on the Web show 120 - 160 degrees. I reached 135. The plug was not cold. I think the protective film was limiting the stretch. The edges were really secure, I excerpted a great deal of force. I am still considering options
That is how I did my RC cubs and how I also did my fp202 Koala; cub wanna-be light-sport kit plane. I used poster board though for the template, took all day and left a small cloud of profanity hanging above my shop. Good video. 👍
Hello Danny, I built up a Venessa Balancer similar to yours to use on my Phoenix Model .55 Size Corsair. It has a 58.5 Inch Wingspan and weighs about 7 pounds. The instructions that came with the Corsair say to balance it up-side-down and establish a CG at 85mm behind the Leading Edge, so I did that. What confuses me a little is why the model when balanced right-side-up, using the same set-up winds up with a different amount of nose weight than when balanced up-side-down. I have a thread on RC Groups where I documented the Venessa Balancer Set-up. I was wondering if you can have a look at it and let me know if I'm using it correctly. I decided to use a Laser Level that projected a Red marker down the side of the Corsair's Fuselage and lined it up with a Horizontal seam between the Hatch and the mating portion of the Fuselage. I thought that would be a good way to determine when the model could be considered "level". I adjusted the weight so that the Red Laser Light ran right down the seam. Some people are balancing their Corsairs right-side-up in the Venessa Balancer and they lay a bubble level on the flat surface below the Rudder to know when the airplane is level, however, again, I question why my test results were different when I flipped the airplane over and tried to balance it right-side-up. Here below is a link to the post I made on the RC Groups Website. Scroll down to Report Number 474 to see my post about Balancing the airplane. www.rcgroups.com/forums/showthread.php?2438030-Phoenix-Models-F4U-Corsair-%28PH011%29/page32#post52227853
That's very interesting, my initial thoughts are that the aircraft should not be level but slightly nose down when the right way up, to bring the wing section level. (Usually the wing is plus a few degrees on the thrust line) with model upside down the nose will need to be slightly up. If you have used the same reference for both then I don't understand.
Denny, here in central Pa we have access to Martin Senour 6394 Red Oxide Glazing Putty that is basically the same exact fine filler you are using & it works fantastic for small imperfections like you just took care of, figured i would throw that in for folk's state side that may be thinking of getting some. Tim
