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Old Jul 17, 2011, 03:24 AM
Avro Vulcan Enthusiast
United Kingdom, London
Joined Jun 2011
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These are the holes cut into the bulkhead. Once glued into the model, I will sand the flat sides smooth to form 63mm dia. holes (The fan is a 55mm fan), The fans will be directly mounted behind here, with smoothed filler to make an intake air duct.
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Old Jul 22, 2011, 12:55 PM
Avro Vulcan Enthusiast
United Kingdom, London
Joined Jun 2011
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A quick update so you can see the new intake, it hasn't been finished yet, but the final form will be far more "areodynamic"
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Old Jul 22, 2011, 01:06 PM
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It can be difficult to tell from photos but the thickness of material seems a little towards the over engineered end of the scale. I have spent a few years very close to micro ducted fan models and whilst the parts are beautifully cut I am concerned that this one is going to be well over weight. Terry's original was made of Depron and thin air, 5mm close grain balsa might be a bit heavy. I am not having a pop but would hate for you to build something that flies like a space shuttle.
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Old Jul 23, 2011, 03:46 AM
Avro Vulcan Enthusiast
United Kingdom, London
Joined Jun 2011
59 Posts
Quote:
Originally Posted by Robert May View Post
It can be difficult to tell from photos but the thickness of material seems a little towards the over engineered end of the scale. I have spent a few years very close to micro ducted fan models and whilst the parts are beautifully cut I am concerned that this one is going to be well over weight. Terry's original was made of Depron and thin air, 5mm close grain balsa might be a bit heavy. I am not having a pop but would hate for you to build something that flies like a space shuttle.
Hey Robert,

I really appreciate you taking time to check on my progress! This is my first EDF so all comments are very welcome. I am very aware that this is going to be a heavy model as I'm looking for scale flying at best, but more than that, this is an experiment, everything I learn I will take to my next one

A scale test of the unglued parts suggests that I'm still on target for 5kg total model weight... Though I have little doubt that you are right and I will have an EDF brick
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Old Jul 23, 2011, 11:33 AM
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Canada
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Originally Posted by bloodline View Post
Good morning gentlemen!
After much debate, my idea is to use four 55mm 4300RPM/V fans each pulling 18A (which should work out to about 200Watts per motor) and each motor delivering 470g of thrust.
Many thanks
I'm thinking that those EDF Perf numbers are a bit optimistic.
AEO persists in lying about their product performances.
DO your own EDF testing to verify thrust/amp numbers.
It may prevent surprises.
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Old Jul 23, 2011, 01:12 PM
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5kg is a bit too much for 4 X 55mm fans especially when you consider that the last 25g always weighs 250g. You should be aiming for under 4.5kg so you should start cutting out lightening holes before you go much further.

Here is our last 4x55 mm fan model, that is 4.2kg.

http://www.rcgroups.com/forums/showt...hlight=sperrin
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Old Aug 01, 2011, 06:12 AM
Avro Vulcan Enthusiast
United Kingdom, London
Joined Jun 2011
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Quote:
Originally Posted by Bare View Post
I'm thinking that those EDF Perf numbers are a bit optimistic.
AEO persists in lying about their product performances.
DO your own EDF testing to verify thrust/amp numbers.
It may prevent surprises.
Yeah, I got a bit wobbly about using 20Amp motors... And opted for 4 30Amp ones to give me a bit of headroom! Glad I did, as I'm getting ~500g of thrust on a 2200mAh 20C battery I should say that my test flights will be on 4 12C 1000mAh batteries (as I have some lying around), not much thrust but should be enough to trimm and balance it, and give me some reliability.

I hope to use 2 3000mAh 20C batteries for proper flying, with one battery powering the outboard motors and the other powering the inboard motors, for obvious reasons

-edit- forgot to note, all my batteries are 3S
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Last edited by bloodline; Aug 01, 2011 at 06:31 AM.
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Old Aug 01, 2011, 06:17 AM
Avro Vulcan Enthusiast
United Kingdom, London
Joined Jun 2011
59 Posts
Quote:
Originally Posted by Robert May View Post
5kg is a bit too much for 4 X 55mm fans especially when you consider that the last 25g always weighs 250g. You should be aiming for under 4.5kg so you should start cutting out lightening holes before you go much further.

Here is our last 4x55 mm fan model, that is 4.2kg.

http://www.rcgroups.com/forums/showt...hlight=sperrin
That sperin is beautiful! I hope I get close to that level of finish

Each wing is coming in at under 0.5Kg and the fuselage is 2kg ( -edit- didn't account for jig pole, the fuselage was actually much lighter)... Without covering... We shall see how I get on
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Last edited by bloodline; May 19, 2012 at 05:02 AM. Reason: made an error in my weights :)
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Old Aug 19, 2011, 04:06 PM
Avro Vulcan Enthusiast
United Kingdom, London
Joined Jun 2011
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A quick update, here is the main airframe uncovered and without completed wing tips, tail fin and control surfaces... but with the fans installed. This structure weighs in at just over 1Kg, which I'm quite happy with.
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Old Aug 19, 2011, 06:04 PM
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she's looking good and fairly light considering building materials.
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Old Aug 20, 2011, 04:36 AM
Avro Vulcan Enthusiast
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Joined Jun 2011
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Originally Posted by LuvEvolution7 View Post
she's looking good and fairly light considering building materials.
Yes, I'm quite pleased with the weight of this completed section... But I will be covering the fuselage in 1.5mm balsa planking... Which will add a lot of weight to the model... I'm gonna keep an eye the weight and plank the areas where I want extra strength first... Then consider my options if I get concerned about weight. Just a note, that this will have about 500g of batteries (just forward of the motors) which will also be used as ballast... The model is slightly tail heavy at the moment.

-Edit- also I have used carbon fibre in place of the original aluminium parts... After my first flight tests, I hope to replace some of the rear support structures with more carbon fibre
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Last edited by bloodline; Aug 20, 2011 at 04:55 AM. Reason: Must stop smoking crack... I'm using 1.5mm balsa planking, not 3mm as originally stated :)
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Old May 19, 2012, 05:00 AM
Avro Vulcan Enthusiast
United Kingdom, London
Joined Jun 2011
59 Posts
A short update...

Work on the model was slow over the winter, I had some employment "issues" :roll eyes: but the last month has been quite productive... so here is the state so far!

Right now we are coming in just over 2kg... the sheeting on the topside of the wing will probably push that up by 500g at least...
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Old May 20, 2012, 03:01 AM
smithy
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Cornwall, UK
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Good to see this thread up and running again, looking very nice.

Phil
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Old May 20, 2012, 07:25 AM
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Subscribed,looks amazing
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Old May 20, 2012, 02:55 PM
smithy
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Cornwall, UK
Joined Dec 2004
524 Posts
http://www.bbc.co.uk/news/uk-18135404
A little inspiration for you.
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