Airfix Spitfire Vb 1/48 NEW tool

[Darius at home]

Well, this thread has encouraged me to actually buy this kit and I am looking forward to building it in the near future. After a Transavia Airtruk and a Robin 400.

Darius

[Otto]

I bought four of them from Hattons in the UK. Even with postage it was less expensive than here in the US. I love the kit.

[Otto]

The Eduard weekend Spitfire IX kit is availible for the same price as the new Airfix kit, don't know where this idea it is expensive comes from.

Not sure what your comment about the "fillet jog" is about , but the new Airfix wing and the Eduard MkIX wing are virtually interchangeable , since these are the best two 1/48 Spitfires on the market I would expect them to be right.

Andrew

This is what I meant by that. If the Eduard kit is an exact fit to the new Airfix Mk.V than they made the same mistake and are the only two kits with it. Every other kit including the Hase and Tami are the same as the ICM and all others. here is a ICM wing taped to the new Mk.V fuse, which you say is the same as the Eduard fuse. It would be a very simple fix though, just a small strip of plastic to fill it in. Unlike if it was the other way around and you would have to cut the chunk out. But I guess that wouldn't be that hard either. Having said all that, I wonder if there is some commonality between the Eduard and Airfix kits. To have the exact same mistake and be almost or actually exact match makes you wonder. This mistake is very minor and can be ignored though or just re-sribed if you are a rivet counter.

Edited August 31, 2014 by Otto

[andrewj]

This is what I meant by that. If the Eduard kit is an exact fit to the new Airfix Mk.V than they made the same mistake and are the only two kits with it. Every other kit including the Hase and Tami are the same as the ICM and all others. here is a ICM wing taped to the new Mk.V fuse, which you say is the same as the Eduard fuse. It would be a very simple fix though, just a small strip of plastic to fill it in. Unlike if it was the other way around and you would have to cut the chunk out. But I guess that wouldn't be that hard either. Having said all that, I wonder if there is some commonality between the Eduard and Airfix kits. To have the exact same mistake and be almost or actually exact match makes you wonder. This mistake is very minor and can be ignored though or just re-sribed if you are a rivet counter.

I think you are making a mistake in assuming the Eduard and Airfix kits are wrong in this respect. Having studied Spitfires for many years , I have only just noticed that there seem to be slight variations in the shapes of the wing root fairings. The Spitfire V BM597 which Airfix based their kit on and which is one of the options in the kit , does indeed have the "joggle" in the forward position as kitted. You can see this by comparing the position to the wingwalk lines.

However , the BBMF's MkIX MK356, has the joggle aft of the wingwalk line , as does the ICM kit.

Another BBMF aircraft PR XIX PS915 has the joggle virtually in line with the wingwalks. Now are these variations due to work done in preservation or are they original, this I don't know , but certainly not all the root fairings are identical. So I think it is wrong to say that any particular kit is wrong until someone can prove it definatively.

Andrew

Edited August 31, 2014 by andrewj

[Jonathan Mock]

I wonder if there is some commonality between the Eduard and Airfix kits. To have the exact same mistake and be almost or actually exact match makes you wonder.

If the supposition is that they somehow shared design data, no. Zero. Nil. Zilch.

You're making the error of taking other, older kits and assuming that because they more of less agree with each other, they must be right, whereas two new kits that most probably benefited from hands on measurements, don't. And let's not get started on scale plans. Plus you've thus far failed to refer to actual aircraft which Andrew has so eloquently illustrated above, which demonstrates some variance.

The simple fix would be to run a tape measure from the leading edge to the "kink" on the real thing and use that as a starting point to see how far the kits agree or disagree.

[Otto]

I think you are making a mistake in assuming the Eduard and Airfix kits are wrong in this respect. Having studied Spitfires for many years , I have only just noticed that there seem to be slight variations in the shapes of the wing root fairings. The Spitfire V BM597 which Airfix based their kit on and which is one of the options in the kit , does indeed have the "joggle" in the forward position as kitted. You can see this by comparing the position to the wingwalk lines.

However , the BBMF's MkIX MK356, has the joggle aft of the wingwalk line , as does the ICM kit.

Another BBMF aircraft PR XIX PS915 has the joggle virtually in line with the wingwalks. Now are these variations due to work done in preservation or are they original, this I don't know , but certainly not all the root fairings are identical. So I think it is wrong to say that any particular kit is wrong until someone can prove it definatively.

Andrew

I stand corrected, there must be variations from airframe to airframe. The one in the museum here in Chicago also has it behind the firewall line as the lower picture has. That is a Mk.I airframe BoB vintage but also updated throughout the war I guess just due to its survival before it was donated to the museum in 1946

Edited August 31, 2014 by Otto

[Griffin]

Interesting pictures, Andrew.

The upper view of Mk IX MK 356 shows the same wing root junction depicted in Monforton book : http://www.arcforums.com/forums/air/index.php?showtopic=278064

It seems to be the same for previous marks, at least from what can be seen here ( and on other period pics ):

http://norenburg.blogspot.fr/2010/07/supermarine-spitfire-west-borneo-i.html

Is anyone tried to compare Airfix kit to reliable informations on the Mk V series ?

Just curious, before ordering one...

[Otto]

I also like the details in the Mk.V picture notice the wheel bulge being very "soft" unlike in other pictures. This would support the detail on the Airfix Mk.I wing. I also like the Flap control horn being exposed in the little hatch. There must have been quite a few variances between aircraft in their subtle details.

Edited August 31, 2014 by Otto

[andrewj]

I also like the Flap control horn being exposed in the little hatch.

Very unusual for a Spitfire in flight , this means the flaps are down . Since they only have two positions , up or down , they were normally only used for landing.

Andrew

[Otto]

Very unusual for a Spitfire in flight , this means the flaps are down . Since they only have two positions , up or down , they were normally only used for landing.

Andrew

This was very likely done to slow the thing down for the "photo-op"

[is it windy yet?]

This was very likely done to slow the thing down for the "photo-op"

That is my opinion of the matter too.

[Otto]

Even at modern airshows the flaps are brought up the instant the aircraft was slowed down enough. This is to prevent serious wing damage incase of ground-loop. This is one reason that if you build a spitfire model with the flaps down the prop better be also represented in the spinning attitude and the tailwheel better be off the ground. That would be the only realistic way to represent a Spit with the flaps down. The only other time I have ever seen the flaps down was during certain maintenance. Otherwise there is too much risk of damage. When these come down they are really down. They are I think more speed brakes than flaps. Flaps are aerodynamically designed to increase wing area and cambor to increase lift. These are designed to create dragg nothing more, hence speed brakes.

Edited September 1, 2014 by Otto

[Otto]

Any of you guys see this? What do you think? http://www.monfortonpress.com/

[Otto]

What really amazes me is when you look at the restored airframes like the ones above and a factory built airframe which spent a little time in the field. The nice clean panel joints really seam to be lacking and the rough fit of the ICM kit seams to come to its own.

[Otto]

Even on this beautifully restored airframe and a couple of seasons behind its belt the seams seam to open up. Just on the airshow circuit with no rough bouncy landings on a unfinished field.

I think I will put away the sanding filler which I was going to use on my ICM kit. Just spread the gear out a little and round off the turtle deck to accept a new (Eduard) canopy and slap on the paint.

[andrewj]

Even on this beautifully restored airframe and a couple of seasons behind its belt the seams seam to open up. Just on the airshow circuit with no rough bouncy landings on a unfinished field.

I think I will put away the sanding filler which I was going to use on my ICM kit. Just spread the gear out a little and round off the turtle deck to accept a new (Eduard) canopy and slap on the paint.

You will find that the Eduard canopy will be too narrow to fit the ICM kit , a vac-form replacement will probably be needed.

Andrew

[Tbolt]

Even at modern airshows the flaps are brought up the instant the aircraft was slowed down enough. This is to prevent serious wing damage incase of ground-loop. This is one reason that if you build a spitfire model with the flaps down the prop better be also represented in the spinning attitude and the tailwheel better be off the ground. That would be the only realistic way to represent a Spit with the flaps down. The only other time I have ever seen the flaps down was during certain maintenance. Otherwise there is too much risk of damage. When these come down they are really down. They are I think more speed brakes than flaps. Flaps are aerodynamically designed to increase wing area and cambor to increase lift. These are designed to create dragg nothing more, hence speed brakes.

Why can't you build a Spitfire parked up with the flaps down?

There seems to be this thing where people who think that if it's not a normal situation then it shouldn't be done. You've said yourself that you've seen them down for maintenance, the aircraft doesn't have to be undergoing a maintenance check to have the flaps down for maintenance. People build models of the Spitfire with the flaps down because they want to show what it looks like with the flaps down, it doesn't make it wrong.

The Spitfire's I've built so far all have their flaps up, but I will build one with them down to show what it looks like.

The split flaps used on the Spitfire increase camber, which increases lift and of course increases drag, that's why they are flaps.

Edited September 2, 2014 by Tbolt

[Tbolt]

Any of you guys see this? What do you think? http://www.monfortonpress.com/

Interesting a digital version, same size as the printed copy and good value at $20. I would be tempted if I didn't have the printed version.

[andrewj]

Why can't you build a Spitfire parked up with the flaps down?

There seems to be this thing where people who think that if it's not a normal situation then it shouldn't be done. You've said yourself that you've seen them down for maintenance, the aircraft doesn't have to be undergoing a maintenance check to have the flaps down for maintenance. People build models of the Spitfire with the flaps down because they want to show what it looks like with the flaps down, it doesn't make it wrong.

The Spitfire's I've built so far all have their flaps up, but I will build one with them down to show what it looks like.

The split flaps used on the Spitfire increase camber, which increases lift and of course increases drag, that's why they are flaps.

Nothing wrong with that , it's your model , if you want the flaps down then build them down. Be aware tho, that the CO will fine you for this, LOL. But seriously the aircraft could be undergoing manintenance or a systems check. I don't know if you've ever sen a Spitfires flaps work , but the're vitually instantaneous, one minute the're up , then bang , the're down and vice-versa, there's no half way at all.

Spitfire flaps are usually only used for landing , the clue is in the name " landing flaps" although for carrier take -offs including the deliveries of Spitfires to Malta , wooden wedges were cut and inserted under the flaps to give extra lift for take off. After take off the flaps were "flicked" open and shut again allowing the wedges to drop away.

Andrew

[Otto]

Why can't you build a Spitfire parked up with the flaps down?

There seems to be this thing where people who think that if it's not a normal situation then it shouldn't be done. You've said yourself that you've seen them down for maintenance, the aircraft doesn't have to be undergoing a maintenance check to have the flaps down for maintenance. People build models of the Spitfire with the flaps down because they want to show what it looks like with the flaps down, it doesn't make it wrong.

The Spitfire's I've built so far all have their flaps up, but I will build one with them down to show what it looks like.

The split flaps used on the Spitfire increase camber, which increases lift and of course increases drag, that's why they are flaps.

I do know a bit about aerodynamics having studied it and worked at it professionally for quite a few years. I can tell you that the Spit flaps do NOT increase camber in their design and are strictly speed brakes. To increase camber with split flaps you have a very limited angle you can drop them and have to provide a slipstream over the top of them to eliminate the vortex drag created by the split.

[Otto]

You will find that the Eduard canopy will be too narrow to fit the ICM kit , a vac-form replacement will probably be needed.

Andrew

I have a Rob Taurus Vac canopy for the Special hobby Mk.V ordered which I think will work. I widened the turtledeck and now the Airfix Mk.Vb canopy would fit also. There are quite a few choices for this. I wound up inserting a .040" (1mm) spacer on the turtle deck to widen the spine behind the glass. Because the turtledeck is actually about .010" too tall than just a simple sanding will shape the back to exactly duplicate the Airfix Mk.Vb.

Edited September 3, 2014 by Otto

[Tbolt]

I do know a bit about aerodynamics having studied it and worked at it professionally for quite a few years. I can tell you that the Spit flaps do NOT increase camber in their design and are strictly speed brakes. To increase camber with split flaps you have a very limited angle you can drop them and have to provide a slipstream over the top of them to eliminate the vortex drag created by the split.

True the Spitfire flaps look almost 90 degrees to the wing but I'm no expert so maybe you can answer this, why do they stop causing lift the further they are put down? Are they not still increasing the camber of the wing lower surface?

Also you mention vortex drag, but isn't that caused by the fact that we have lift being created, otherwise how are we getting vortex drag?

If you look in a Spitfire Pilot's manual you will see that a flaps down approach is 10 to 15 knots slower than a flap up approach, is that not the case because the aircraft can fly slower because of the increased lift of the flaps?

Edited September 3, 2014 by Tbolt

[Brad-M]

What about mating the wing tops of the Airfix Mk IXc with their Mk Vb fuselage and wing bottoms, to get to a Mk Vc, how's the fit there? I don't have either kit, so I am wondering if that might work. I see that the Dzus fasteners on the Airfix Vb are still raised, but a swipe or two with a sanding stick will fix that.

Cheers

Brad

[Mfezi]

I do know a bit about aerodynamics having studied it and worked at it professionally for quite a few years. I can tell you that the Spit flaps do NOT increase camber in their design and are strictly speed brakes. To increase camber with split flaps you have a very limited angle you can drop them and have to provide a slipstream over the top of them to eliminate the vortex drag created by the split.

I cannot agree with your statement that they only act as speed brakes. Split flaps cause a significant increase in both drag and maximum lift coefficient. During WWII they were quite popular and there are many reports on various wind tunnel test programs that investigated the effect of split flaps. Here is one (of many) examples:

F.F. Fullmer, Jr, "Wind-Tunnel Investigation of NACA 66(215)-216, 66,1-212, and 65_1-212 Airfoils with 0.20 Airfoil-Chord Split Flaps", NACA Confidentiality Bulletin LG410, July 1944

(You can download it here: http://ntrs.nasa.gov/search.jsp?R=19930092780)

Summary from that report (section maximum lift coefficients), 20% chord split flaps:

NACA 66(215)-216 Cl,max (no flap): 1.56 Cl,max (70 deg flap): 2.61

NACA 66,1-212 Cl,max (no flap): 1.41 Cl,max (70 deg flap): 2.17

NACA 65_1-212 Cl,max (no flap): 1.49 Cl,max (60 deg flap): 2.15

Further in the report you'll see the plots for intermediate deflections - the split flaps have pretty much the same effect as a plain flap: The Cl-alpha curves shift up with increasing flap deflection, the Cl,max increase and move slightly to the left (it stalls at a slightly lower angle of attack, but higher lift coefficient) and the pitching moment of the airfoil becomes significantly more negative with the flap deflected. All these characteristics are very similar to the camber effect of a plain flap or other types of flaps.

If you search around you will find similar reports for other airfoil sections equipped with split flaps - they all work more-or-less the same.

Of course, there are considerably more efficient flap arrangements (slotted, fowler, etc) but split flaps essentially do the two major things you need a flap to do, namely increase maximum lift coefficient ("camber effect") and increase drag, and are pretty easy to install and actuate, therefore their popularity in WWII.

[Otto]

I cannot agree with your statement that they only act as speed brakes. Split flaps cause a significant increase in both drag and maximum lift coefficient. During WWII they were quite popular and there are many reports on various wind tunnel test programs that investigated the effect of split flaps. Here is one (of many) examples:

F.F. Fullmer, Jr, "Wind-Tunnel Investigation of NACA 66(215)-216, 66,1-212, and 65_1-212 Airfoils with 0.20 Airfoil-Chord Split Flaps", NACA Confidentiality Bulletin LG410, July 1944

(You can download it here: http://ntrs.nasa.gov...p?R=19930092780)

Summary from that report (section maximum lift coefficients), 20% chord split flaps:

NACA 66(215)-216 Cl,max (no flap): 1.56 Cl,max (70 deg flap): 2.61

NACA 66,1-212 Cl,max (no flap): 1.41 Cl,max (70 deg flap): 2.17

NACA 65_1-212 Cl,max (no flap): 1.49 Cl,max (60 deg flap): 2.15

Further in the report you'll see the plots for intermediate deflections - the split flaps have pretty much the same effect as a plain flap: The Cl-alpha curves shift up with increasing flap deflection, the Cl,max increase and move slightly to the left (it stalls at a slightly lower angle of attack, but higher lift coefficient) and the pitching moment of the airfoil becomes significantly more negative with the flap deflected. All these characteristics are very similar to the camber effect of a plain flap or other types of flaps.

If you search around you will find similar reports for other airfoil sections equipped with split flaps - they all work more-or-less the same.

Of course, there are considerably more efficient flap arrangements (slotted, fowler, etc) but split flaps essentially do the two major things you need a flap to do, namely increase maximum lift coefficient ("camber effect") and increase drag, and are pretty easy to install and actuate, therefore their popularity in WWII.

I do agree to all of this. I never said that "split flaps do not increase lift or camber" I did say that they do not on the Spitfire configuration. Because the deployment is way too extreme to give efficiency of this effect.. If they could be deployed in lower angles of incidence than this would be true. This would work because the vortex coefficient behind the open flap would result in a vacuum which would pull the upper airflow down smoothly over the trailing edge instead of creating a simple vortex of drag well before the trailing edge. Every airfoil and wing configuration would be a bit different but normally all deployment to increase lift is 30 degrees or less. in some very precise situations you can get away with 45 degrees but the wing would have to be designed with bypass airflow in front of the flap.