1/48 Avro 707A

[wellsprop]

9 hours ago, John R said:

Sorry to rain on your parade but the fuselage/intake junction is incorrect. Have a look at the pictures in here.

 

No worries, thanks for pointing this out, I hadn't realised. It actually looks like the nose of the aerofoil has been cut off (at the cross section where the wing joins the fuselage). Unfortunately, it's unlikely I'll be able to accurately model this without section plans and/or re-doing a lot of work - It will most likely be easiest just to sand away the area not required (as has been done for the 1/72 kits).

[John R]

There is something not quite right about your argument but I can't put my finger on what it is. I agree that it looks as if the nose of the aerofoil has been cut off. I wonder if the aerofoil shape at the root should have a less pointed profile.

where did you get the drawing shown in the first post? It does seem to show the correct shape at the root, something that is not right in any other drawings or models that I have seen.

Is it possible to show a views of your model that show the same aspect as these pictures? Note that the wing/fuselage join appears to be an almost straight line.

I'm trying to get it in 3D using Milliput and sandpaper on a Pro Resin version!

John

 

 

[wellsprop]

@John R, agreed, it looks like it has a very blunt nose (that's what I meant by cut-off aerofoil  ).

 

This is more or less the same angle, on the real aircraft, the wing/fuselage join curves distinctly outwards towards the wing fence (i.e. the leading edge is further back) - see my model below, the wing/fuselage join by the fence is almost straight (from this angle).

 

 

I got the plans from google images! There's a couple different plans, none quite match, the 3D model is my interpretation of the plans and the aircraft.

 

I must add (as with all my 3D designs), I'm not at all knowledgeable on the subject, I'm just playing around with CAD and getting something that looks about right!

[bentwaters81tfw]

What you are looking at is a scaled down standard Vulcan intake:

You've seen one, you've seen them all.

[John R]

Here is a very rough mod showing what I meant. The intake has been removed and the gap filled with Milliput to show the shape of the wing without the intake. The second picture shows the forward edge cut off.

 

 

 

The red lines show (very roughly) the wing root with the front cut off and the black line in front shows it before the cut off

[bentwaters81tfw]

There's too much root behind the splitter plate, but apart from that, it looks pretty close. The next one will be better.

 

 

[wellsprop]

I'll see what I can do, slightly concerned all the panel lines etc will fall over if I modify the wing!

 

Fingers crossed, otherwise I might have to live with it...

[bentwaters81tfw]

8 minutes ago, wellsprop said:

I'll see what I can do, slightly concerned all the panel lines etc will fall over if I modify the wing!

 

Fingers crossed, otherwise I might have to live with it...

I meant mine, but the image didn't show. Fixed now.

[wellsprop]

I've just looked at the plans I've used, the plans are correct and show the wing root just as John R has explained - i.e. I made an omission in my model!

 

I'm perfectly happy to be quite open with the inaccuracies within my CAD model, this capture highlights the incorrect wing root at the tip, slightly incorrect wing/fuselage join and an imperfect outer intake profile.

 

 

Regarding the wing/fuselage join line, it's incredibly hard to get this accurate without comprehensive engineering drawings. The join is affected by the aerofoil profile, the wing incidence and the dihedral/anhedral. The anhedral/dihedral can be estimated from the plans, the wing incidence cannot (I'm not sure if the incidence varies along the span - one would expect the incidence to be greater at the root than the tip - this called washout), I know the aerofoil is a symmetrical NACA 0010 (modified), I am unsure how it has been modified. I created the aerofoil by writing the NACA 4 series equation in excel and imported it into CATIA using a VBA before translating, scaling and rotating the aerofoil accordingly.

 

Playing around with the model it appears that, unfortunately, correcting the mistake on my model will require a complete redesign of the wing (which will probably upset the panel lines on both the wings and the fuselage), I'm not too keen to do that! So the final model will require some reworking by hand, until I find the motivation to redesign it all that can firmly go on the (ever-growing) "to-do" list" 🙃 

 

That said, given how many 1/48 Avro 707 kits are available, I'd suggest this is the best option hehe! And if @bentwaters81tfw incredible work on the 1/32 Mig 15 / Vulcan kitbash is anything to go by, I think this will turn out alright in capable hands

[bentwaters81tfw]

This leads to a question. My experience of printed kits is that the materials used for printing are based on Nutronium and require an angle grinder to re shape them. What do you propose to use as a medium? And how does it take to abrasive re shaping?

 

Another possibility for obtaining the correct intake shape would be the parts breakdown, if the join abuts the splitter plate, could the intake be made without the curves? 

[wellsprop]

8 minutes ago, bentwaters81tfw said:

This leads to a question. My experience of printed kits is that the materials used for printing are based on Nutronium and require an angle grinder to re shape them. What do you propose to use as a medium? And how does it take to abrasive re shaping?

 

Another possibility for obtaining the correct intake shape would be the parts breakdown, if the join abuts the splitter plate, could the intake be made without the curves? 

Filing/sanding is the same for 3D printed resin as it is for any other type of resin from my experience. So it does take longer than with plastic! Probably best to cut out the incorrect bit first.

 

I've realised I should be able to sort out the intake where it meets the splitter plate quite easily and I can potentially do a Boolean subtract on the wing root tip to get a better profile (this avoids remodelling the wing and therefore keeps the panel lines).

 

Work to do!

[wellsprop]

I've managed to sort out the incorrect wing root profile, the way I've done it is quite messy, but it works...

 

 

I am aware the splitter plate by the intake is too thick (1mm ~ 2 inches in 1:1), however, there is very little I can do about it due to the tolerances required for 3D printing.

[John R]

I agree with you about the complexity of the wing root/fuselage junction. I reckon that it is even harder to get right when trying to correct an inaccurate wing made from resin.

Regarding plans. After reading your comments about finding different versions from Google I followed the same route with interesting results. I had only Barrie Hygates version to start with and as he referenced the actual a/c, Bae archives and gave actual dimensions I expected these to be reliable but there are some obvious errors, notably in the area of the intake/fuselage junction. Other versions seem to have got the latter correct but have the wrong wing LE sweep.

I am curious about why you did not follow the intersection line on the drawing as this looks as if it would have given the correct shape.

John

[wellsprop]

@bentwaters81tfw @John R I've corrected the wing root, also thinned the splitter plate (this runs the risk of not printing properly!) and I have remodelled the intake profile.

 

So far, I have got the correct top and side profile, but I'm not sure how the actual intake itself should look...

 

 

 

Suggestions welcomed! (I'm aware I need to add some fillets to the sides).

[mahavelona]

On 29/09/2020 at 21:54, bentwaters81tfw said:

This leads to a question. My experience of printed kits is that the materials used for printing are based on Nutronium and require an angle grinder to re shape them. What do you propose to use as a medium? And how does it take to abrasive re shaping?

 

Another possibility for obtaining the correct intake shape would be the parts breakdown, if the join abuts the splitter plate, could the intake be made without the curves? 

From my own experience with a WellsProp kit I have found the resin sands very easily. I have used various grades of wet and dry.

 

The 3d model is.lookong smashing so far - have to keep stepping back from the small details and taking in what has already been achieved! 

[Adam Poultney]

On 29/09/2020 at 15:43, bentwaters81tfw said:

What you are looking at is a scaled down standard Vulcan intake:

You've seen one, you've seen them all.

Not to be overly pedantic, but wouldn't the 707A be more like the Vulcan B1 intake?

Edited October 3, 2020 by Adam Poultney

[Shar75]

On 30.09.2020 at 12:25, wellsprop said:

@bentwaters81tfw @Джон Р Я исправил корень крыла, также утончил разделительную пластину (это может привести к неправильной печати!) и переделал профиль воздухозаборника.

 

Пока у меня есть правильный верхний и боковой профиль, но я не уверен, как должен выглядеть сам воздухозаборник...

 

 

 

Предложения приветствуются! (Я знаю, что мне нужно добавить несколько скруглений по бокам).

Greetings!
Tell me, how is your Avro 707 project doing?
Is it possible to buy your kit for this aircraft?
Thanks!

[wellsprop]

Hi @Shar75, it's on the "to complete" list at the moment! Keep an eye on this thread for updates

[Shar75]

2 minutes ago, wellsprop said:

Привет@Шар75, он сейчас в списке "на завершение"! Следите за обновлениями в этой теме

Thank you very much!
Is there any hope that the project will be completed?
If so, can I be listed as a buyer?
Thank you for creating sets of such models!