G
can`t wait bud
Another Parnall Elf
- Thread starter Greyhead
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G
hope to be reading the next part soon 
oster_ke
oster_keGrahame once again some really useful and practical tips here,these scale details make all the difference in the world to a model,your piano hinge looks most convincing.
These are the tasks that really eat up the time but if you enjoy doing them then that is the main thing to improve the end product,the Parnall Elf just has such great character.
I was a bit alarmed last year when Shuttleworth were considering selling her off,she would have vanished Stateside never to be seen again,thankfully someone saw sense and she has been retained at Old Warden.
These are the tasks that really eat up the time but if you enjoy doing them then that is the main thing to improve the end product,the Parnall Elf just has such great character.
I was a bit alarmed last year when Shuttleworth were considering selling her off,she would have vanished Stateside never to be seen again,thankfully someone saw sense and she has been retained at Old Warden.
No time today, terrible thing having to earn a living, roll on retirement!
Just a photo of the exhaust side of the cowl.
View attachment 263281
Reading through my last post I realise that I didn’t explain how to ensure a well fitting cowl, wonderful thing hindsight.
First of all make the templates for the formers using the model not the plans, remember to remove 1/16th for the covering, mark the hinge line and partly cut. Then fit the balsa longerons with the assembly in situ using cling film to stop unwanted adhesions, only then fully cut the sections free.
Just a photo of the exhaust side of the cowl.
View attachment 263281
Reading through my last post I realise that I didn’t explain how to ensure a well fitting cowl, wonderful thing hindsight.
First of all make the templates for the formers using the model not the plans, remember to remove 1/16th for the covering, mark the hinge line and partly cut. Then fit the balsa longerons with the assembly in situ using cling film to stop unwanted adhesions, only then fully cut the sections free.
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G
Hello,
Your work is impressive. Your technical solutions are constructive and original.
I'm also at the the bench with a 1/3 Tipsy Junior. It's also a long time project with pauses.
Hope to read you soon on the forum.
Congratulations,
Marc.
Your work is impressive. Your technical solutions are constructive and original.
I'm also at the the bench with a 1/3 Tipsy Junior. It's also a long time project with pauses.
Hope to read you soon on the forum.
Congratulations,
Marc.
The cowl is covered with a combination of litho plate and printer paper. Where there are compound curves use litho but for flat plates printer paper is lighter and easier to stick, it’s also a lot cheaper, if you can’t find a friendly printer. The rivet lines are embossed from the rear using a dressmaker’s pattern copying wheel, the spacing may not be correct but who knows? At least they’re evenly spaced. For individual rivets use an old “Biro”.
The louvers are a simple job on the Elf as they are separate items riveted on. They are made from strips of litho bent to shape and glued through holes cut in the side panels. Don’t be tempted to just stick them on the outside; they’ll look terrible and won’t help to keep your precious engine cool! The secret is to mark out all the holes, cut the first hole and glue the louver in before cutting the next hole. This maintains the curvature of the panel. I also strengthened the strips between the louvers with a few carbon fibre tows but this is not really necessary, it was just a bit of “belt and braces”.
The exhaust is from paper rolled around a felt tip pen. Use medium cyano and then roll the pen on the workbench adding more glue as needed. I use kitchen foil, as it appears to be about the only thing cyano won’t bond to, to stop the lot sticking to the pen. Coating with a mixture of 30min. epoxy and micro balloons produces the pitted surface if you keep dabbing it with a “suitable implement” for the first few minutes as it cures.
View attachment 263282
The “suitable implement” I used was my finger but I’m sure the Health and Safety establishment would tell me I’m storing up all manner of ills for the future, so the choice is yours!
The louvers are a simple job on the Elf as they are separate items riveted on. They are made from strips of litho bent to shape and glued through holes cut in the side panels. Don’t be tempted to just stick them on the outside; they’ll look terrible and won’t help to keep your precious engine cool! The secret is to mark out all the holes, cut the first hole and glue the louver in before cutting the next hole. This maintains the curvature of the panel. I also strengthened the strips between the louvers with a few carbon fibre tows but this is not really necessary, it was just a bit of “belt and braces”.
The exhaust is from paper rolled around a felt tip pen. Use medium cyano and then roll the pen on the workbench adding more glue as needed. I use kitchen foil, as it appears to be about the only thing cyano won’t bond to, to stop the lot sticking to the pen. Coating with a mixture of 30min. epoxy and micro balloons produces the pitted surface if you keep dabbing it with a “suitable implement” for the first few minutes as it cures.
View attachment 263282
The “suitable implement” I used was my finger but I’m sure the Health and Safety establishment would tell me I’m storing up all manner of ills for the future, so the choice is yours!
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G
Exhaust is superb ! I thought you had welded-up a miniature metal one and then put it out in the rain for a couple of years. Cant wait to see the Albatros.
The twin air scoops are made from litho and really help the cooling by directing air down over the rocker box onto the cylinder block. The other bits and pieces use litho, copper wire, brass tube and washers.
You get a good view of the cabane struts with a coat of paint in this view and can just about make out the carbon fibre "tongues" that lock the wings in place.
The Elf logo was printed onto self adhesive white paper, once again after a bit of manipulation using Photoshop.
View attachment 263283
The fasteners are not functional, the sides are held in place by magnets, very useful items these, they also hold the luggage hatch and the rear section of the lower wings which fold down to allow the main wings to fold back. There’s a thread about them on the site, they are still available from Maplin and in fact I’ve just bought a new supply today. I prefer the ones originally designed to be used as electrical connectors, they are in a metal holder with a stiff wire attached; this helps with the positioning.
Code: N51AK
Description: Magtrix Connectors
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You get a good view of the cabane struts with a coat of paint in this view and can just about make out the carbon fibre "tongues" that lock the wings in place.
The Elf logo was printed onto self adhesive white paper, once again after a bit of manipulation using Photoshop.
View attachment 263283
The fasteners are not functional, the sides are held in place by magnets, very useful items these, they also hold the luggage hatch and the rear section of the lower wings which fold down to allow the main wings to fold back. There’s a thread about them on the site, they are still available from Maplin and in fact I’ve just bought a new supply today. I prefer the ones originally designed to be used as electrical connectors, they are in a metal holder with a stiff wire attached; this helps with the positioning.
Code: N51AK
Description: Magtrix Connectors
Page: 582
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good posting dude
The inkjet vinyl for making the logos is available from Overlander Batteries and comes in clear or white and costs £9.00 for between 8 and 10 sheets depending on the specification. On the white film I get good results using the 'Photo Quality Glossy Film' setting on my Epson printer but beware it can take a quite a while to dry so be careful not to smudge it. I have not tried clear film.
Thanks for that Dave, If anyone else has anything to add (or ask) just post away!
It's also a good idea to seal the printout before you cut it out to prevent smudges, I used clear spray lacquer from an automotive suppler.
The windscreens are simple affairs cut from acetate sheet. The fairing is from litho formed on this jig and the “bolts” are cut down pins. To make the job of painting the fuselage easier they were not fitted until it was ready for the final coat hence the painting of the fairing.
View attachment 263285
When forming shapes such as this from litho it is important to cut it oversize to allow for the stretching etc. However too much excess and it tends to stop the litho holding its shape and forms folds, so as you work keep trimming the edges, it soon becomes obvious where you’ve left too much material.
Don’t try to do the job in one go, form it partly to shape, trim off excess, form some more, trim again and so on. It’s amazing how complex a shape you can get out of a flat sheet of litho.
It's also a good idea to seal the printout before you cut it out to prevent smudges, I used clear spray lacquer from an automotive suppler.
The windscreens are simple affairs cut from acetate sheet. The fairing is from litho formed on this jig and the “bolts” are cut down pins. To make the job of painting the fuselage easier they were not fitted until it was ready for the final coat hence the painting of the fairing.
View attachment 263285
When forming shapes such as this from litho it is important to cut it oversize to allow for the stretching etc. However too much excess and it tends to stop the litho holding its shape and forms folds, so as you work keep trimming the edges, it soon becomes obvious where you’ve left too much material.
Don’t try to do the job in one go, form it partly to shape, trim off excess, form some more, trim again and so on. It’s amazing how complex a shape you can get out of a flat sheet of litho.
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Just the undercarriage left to do and the fuselage is virtually finished. This was simple as the plan was near enough for me, except for the missing rear strut but this is non-functional and made from plastic tube. The piano wire was bent to shape and silver soldered, soft solder really isn’t up to the job even if the joins are bound with wire before soldering. The fairings are made from balsa but as it is impossible to get a sharp edge they are covered with litho.
The wheels are attached as per wonwinglo’s instructions in the tutorial forum except that I used a 14BA bolt instead of a split pin.
Sorry but no photos of the undercarriage being built, if anybody’s interested I can take some of it completed and fitted.
Now just stick on as many of the numerous brackets and strengthening plates as you can be bothered with, tape the joints and it’s ready for painting.
Remember to build light, having due regard for strength, because all these little bits and pieces soon start to pile on the weight. By the way I never bother to weigh my finished models, if it’s light it’ll fly that much better but if it’s over-weight it’s too late to do anything about it!
The wheels are attached as per wonwinglo’s instructions in the tutorial forum except that I used a 14BA bolt instead of a split pin.
Sorry but no photos of the undercarriage being built, if anybody’s interested I can take some of it completed and fitted.
Now just stick on as many of the numerous brackets and strengthening plates as you can be bothered with, tape the joints and it’s ready for painting.
Remember to build light, having due regard for strength, because all these little bits and pieces soon start to pile on the weight. By the way I never bother to weigh my finished models, if it’s light it’ll fly that much better but if it’s over-weight it’s too late to do anything about it!
Good tips on the decal printout Grahame,for anyone trying out this system buy a spray can of acrylic clear from the art shop,they have a soft sprayhead and this seals the otherwise water soluble ink used in these ink jets printers,just make sure that ink is really dry before even attempting to spray it on as a sealer.
Excellent litho tips as well,amazing material and it is free if you can find a friendly printer,we will be dealing more with this product in the near future here and explaining its many uses on models.
Great material,just keep it rolling ! good job that you had the foresight to photograph it all whilst building.
Excellent litho tips as well,amazing material and it is free if you can find a friendly printer,we will be dealing more with this product in the near future here and explaining its many uses on models.
Great material,just keep it rolling ! good job that you had the foresight to photograph it all whilst building.
G
Grahame,
Have read the whole thread....Fantastic...!!!!!! Excellent workmanship and a Superb model that shows it too...!!! You are clearly an experienced modeller and the photos are a real credit to you. Keep up the good work. Posts like this are always a pleasure to read.
Regards.......Mark
Have read the whole thread....Fantastic...!!!!!! Excellent workmanship and a Superb model that shows it too...!!! You are clearly an experienced modeller and the photos are a real credit to you. Keep up the good work. Posts like this are always a pleasure to read.
Regards.......Mark
*** Was just going to ask you about the weight Grahame ! you will need to give us some tips on the silver soldering ie materials to use,any special fluxes etc I like the way that you have done the lower curved axle bit on the undercarriage.
Biplanes do certainly add up on weight,all those metal fittings and wire etc the glide angle on my model is not too good she needs to be powered onto the ground and flared very precisely,I have never looped mine just content to observe that lovely biplane shape in the air.
That’s the fuselage finished ready for painting but if there’s anything you’re interested in that I’ve missed just let me know.
Now the wings. When building scale fabric covered wings we can’t use the normal modelling technique of top and bottom spars with or without sheeted leading edge (unless that’s scale of course!) as the fabric needs to sag in-between the ribs. Unfortunately this “D box” is what gives the wing most of it’s strength but I’ve devised a system which goes a long way to replacing the strength whilst retaining the scale appearance.
The wing has a front laminated spar and a spruce rear spar to which the hinge is attached, if the wings weren’t folding the rear spar could be missed out altogether or at least made from balsa to save weight.
View attachment 263286
The front spar is a spruce / balsa / spruce laminate with the balsa extended to go through the leading edge with the direction of the grain from LE to spar. The ribs are made in 2 pieces; the top front section is added after the composite spar with additional sections as “riblets”. The leading edge is 2 lengths of square balsa glued top and bottom of the balsa lamination.
Before covering, the ribs and more so the “riblets” are very vulnerable to damage whilst you do the other 101 necessary things to the wing. The answer here is to make a small hole in each of the pieces, it’s easier to do this before gluing in place, and then thread some strong cotton through the holes to make a “necklace”. After gluing in place, soak the cotton (button thread is the best) with thin cyano. It’s amazing how much this cotton also increases the torsional strength of the wing.
Now the wings. When building scale fabric covered wings we can’t use the normal modelling technique of top and bottom spars with or without sheeted leading edge (unless that’s scale of course!) as the fabric needs to sag in-between the ribs. Unfortunately this “D box” is what gives the wing most of it’s strength but I’ve devised a system which goes a long way to replacing the strength whilst retaining the scale appearance.
The wing has a front laminated spar and a spruce rear spar to which the hinge is attached, if the wings weren’t folding the rear spar could be missed out altogether or at least made from balsa to save weight.
View attachment 263286
The front spar is a spruce / balsa / spruce laminate with the balsa extended to go through the leading edge with the direction of the grain from LE to spar. The ribs are made in 2 pieces; the top front section is added after the composite spar with additional sections as “riblets”. The leading edge is 2 lengths of square balsa glued top and bottom of the balsa lamination.
Before covering, the ribs and more so the “riblets” are very vulnerable to damage whilst you do the other 101 necessary things to the wing. The answer here is to make a small hole in each of the pieces, it’s easier to do this before gluing in place, and then thread some strong cotton through the holes to make a “necklace”. After gluing in place, soak the cotton (button thread is the best) with thin cyano. It’s amazing how much this cotton also increases the torsional strength of the wing.
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The rest of the main construction of the bottom wings was fairly straightforward. The hinges are pinned, again using model railway track pins, to the rear spar, glued with epoxy (see early photo) and finally given a few wraps with carbon fibre tows. The rear section of the bottom wings is hinged using commercial flat plate hinges and is held in place by 2 small magnets, the theory being that the air flow will keep them in position once the airspeed has built up and this has proved to be the case.
The photo below shows the mechanism for locking the wings in place. There is very little tension in the springs when locked, they’re just there to stop any movement caused by vibration. They lock into slots cut into free-floating tongues that pass right through the top centre section and fuselage.
The tongues were originally made from 1.5mm paxolin circuit board but having given it some thought I came to the conclusion that the model would have better flight characteristics if the wings stayed in the non-folded position during flight, so I replaced the tongues with ones made from carbon fibre sheet!
View attachment 263287
If you haven’t used carbon fibre tows before I can highly recommend them where some extra strength is needed without adding too much weight. Just a few strands glued using epoxy, the best but a bit messy, or cyano, watch out for the fumes, will greatly increase the strength. I also moulded the tailskid from carbon fibre tows and epoxy; it has produced a very strong, light and flexible job.
The photo below shows the mechanism for locking the wings in place. There is very little tension in the springs when locked, they’re just there to stop any movement caused by vibration. They lock into slots cut into free-floating tongues that pass right through the top centre section and fuselage.
The tongues were originally made from 1.5mm paxolin circuit board but having given it some thought I came to the conclusion that the model would have better flight characteristics if the wings stayed in the non-folded position during flight, so I replaced the tongues with ones made from carbon fibre sheet!
View attachment 263287
If you haven’t used carbon fibre tows before I can highly recommend them where some extra strength is needed without adding too much weight. Just a few strands glued using epoxy, the best but a bit messy, or cyano, watch out for the fumes, will greatly increase the strength. I also moulded the tailskid from carbon fibre tows and epoxy; it has produced a very strong, light and flexible job.
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:great: oster_ke
oster_keAn “eagle eye” has noticed that in the above posts I’ve said to thread the rib fronts to make a “necklace” before gluing in place but in the photo of the wing lock there’s no button thread to be seen! This is precisely why I’ve also said it is easier to do it that way. I built the bottom wings and then found out the hard way just how vulnerable the ribs were, i.e. I damaged a lot of them, that is when I worked out the idea of the thread and when it worked I incorporated it into the build for the top wings which was a lot easier.
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