P-51D Mustang by Lt. Biggles - Eduard - 1/48 - PLASTIC

[Lt. Biggles]

Time to begin my next project while the B-17 gets its finishing touches.

This one also I’ll not be keeping myself, but unlike the fortress, this time I have an actual plane to replicate. 

This makes it easier mainly and perhaps occasionally more difficult.

For this kit I have Eduards, Profi Pack edition, so will be an out of the box build. As it contains cockpit masks and Photo Etch I’ll not get any aftermarket parts.

The subject for this build will be,

Lt. Donald F. Vulgamore’s P-51D, E9-V “Jaspers Joker II” who flew as part of the 361st Fighter Group in Europe.

The reason for this subject is the paint scheme!

It has a yellow nose, NMF (natural metal finish) and doesn’t have the full D-Day invasion stripes. So it ticked all the boxes. To top it off I managed to find decals for this very build.

If I can find spray stencils I may give them a go otherwise I’ve got the decals and I’ve heard good things about Aero Master decals printed in Italy by Cartograf. They weren’t easy to find as they aren’t made anymore and bought mine from a collector it seems! 
 

I think this will be a faster build than the B-17 and I’m looking forward to trying my first ever natural metal finish. Each build I try to do something new and push my abilities. This time the NMF will be that part!

So any tips at all about how to get a weathered war weary aluminium look I’m all ears! I’ve got some Mr. Color Super Metallic 2 lacquer paints, Super Fine Silver 2, Super Duralumin and Super Iron 2 which will be new for me to try.

Ive been doing a lot of research over the last month and have a 1/72 mustang prepped as my test mule. Currently the undersides of the wings are an assortment of different base colours to see how much of an effect they have, as it’s one thing to be told something and another to see for yourself. 

Im expecting the build to be pretty straight forward and once at the prep for painting stage I’ll be in new territory.

 

[king derelict]

I look forward to seeing this build with interest. I’ve been curious about the Profipack kits and I’m trying to work up to a Naural Metal Finish on the Yak.

alan

[Dave_E]

I’ll watch! 🍿🥤👍😀

[Egilman]

16 hours ago, Lt. Biggles said:

Ive been doing a lot of research over the last month and have a 1/72 mustang prepped as my test mule. Currently the undersides of the wings are an assortment of different base colours to see how much of an effect they have, as it’s one thing to be told something and another to see for yourself. 

It depends on the final look you want, most of the sprays give a flavor of new metallic with varying grades of shine, although I've been impressed with a few of the sprays that have been coming out...

For shiny aluminum, gloss black undercoat with a thinned aluminum overcoat, for an oxidized aluminum finish dark grey gloss with a bit heavier coat of aluminum... Me I will still do it in RnB... But that's the old school way...

 

I'll be following brother...

[Lt. Biggles]

3 hours ago, Egilman said:

It depends on the final look you want, most of the sprays give a flavor of new metallic with varying grades of shine, although I've been impressed with a few of the sprays that have been coming out...

For shiny aluminum, gloss black undercoat with a thinned aluminum overcoat, for an oxidized aluminum finish dark grey gloss with a bit heavier coat of aluminum... Me I will still do it in RnB... But that's the old school way...

 

I'll be following brother...

As always glad to have you along! You always have good tips and tricks up your sleeve!

I’d love to go for the oxidised aluminum.

Well that’s the goal at least!

 

I will try giving different grey undercoats a go! Thanks for these tips!

does it need to be a gloss coat? 
I will try gloss and Matt undercoats and see if it’s different. And also gloss and Matt clear coats over top!

About the thickness. I’m abit worried about loosing all the details if I do a primer, a few coats of thick gloss paint and polish then wet coats of my aluminum.

In my tests I’m trying to get the gloss black thick enough to get the smooth surface otherwise I get the almost patterned finish. If I try sand it back smooth then I sand back to plastic and so the paint needs to be thick enough to sand! I’m secretly hoping I can paint the super metallics over the Matt primer if my prep is good enough.

I’ve not sprayed any of the super metallics yet as I need to go get a respirator and set up a place in the outside garage due to the smell! I’ll not get away with spraying lacquers on the dining room table 😬

[Lt. Biggles]

11 hours ago, king derelict said:

I look forward to seeing this build with interest. I’ve been curious about the Profipack kits and I’m trying to work up to a Naural Metal Finish on the Yak.

alan

I’ve also been keeping an eye on your build to see how you will do yours and any tips and tricks or dos and donts! 
Here is to us managing to get lucky and land a result we are both happy with on our first attempt 🍻

[Lt. Biggles]

6 hours ago, Dave_E said:

I’ll watch! 🍿🥤👍😀

Welcome along! 

[Lt. Biggles]

The NMF experiments have begun on my 1/72 scale test mule.

This is what I’ve learned so far.

Smooth smooth smooth!

I think that’s all there is to it really.

so I just need to find away to make the smoothest surface with the thinnest amount of paint to keep all the surface details.

I also learned that the gloss base isn’t just because it shines through and makes the paint more shiny and metallic it’s that gloss has a smoother surface.

Here the far left has the gloss black under it and the rest is the Matt surface primer. And the changes are just applying more coats… which makes it smoother and so a better finish.

Here the wing on the right from our perspective is straight on the Matt primer. On the left I gave the primer a quick sand with 1200 grit sand paper and it’s noticeably better except you can see the scratches in it, so I’ll need to find super fine sand paper.

 

My next lot of tests will be to sand down the primer as smooth as I can and see if that is ok. Or if I need to spray something on the primer that I can make smooth.

Any ideas are more than welcome!

 

These paints are really nice to work with though!! 

[Lt. Biggles]

The cockpit has begun on the real model now. I’ve ordered some 3000 grit sanding sponges and will be part of my next experiment with the paint mule.

 

Made my own mix of interior green with tamiya green and yellow mix while making the Fortress and seems to do the job well. I wanted to make the colour in a bottle so I can do touch ups and all the rest of the parts without having to mix it each time!

Put down some buff colour then brown oil paint streaked on top to give a wood grain effect.

Once dry I’ll seal it in with a clear coat then try out my chipping fluid and paint with rubber black and scuff up the floor alittle. Letting the oil dry might take a good few days though.

So begun on the bits behind the seat. One part has to be a battery and the other maybe a radio but kinda looks like a battery also! Anyway good fun parts to detail that I don’t think will be visible once finished.

[Javlin]

The last kit of these I did the fit was very Nice the stencils are some of the worst I have used might just be me the build fought me to the end .

[Javlin]

On 9/26/2024 at 1:51 AM, Lt. Biggles said:

The NMF experiments have begun on my 1/72 scale test mule.

This is what I’ve learned so far.

Smooth smooth smooth!

I think that’s all there is to it really.

so I just need to find away to make the smoothest surface with the thinnest amount of paint to keep all the surface details.

I also learned that the gloss base isn’t just because it shines through and makes the paint more shiny and metallic it’s that gloss has a smoother surface.

Here the far left has the gloss black under it and the rest is the Matt surface primer. And the changes are just applying more coats… which makes it smoother and so a better finish.

Here the wing on the right from our perspective is straight on the Matt primer. On the left I gave the primer a quick sand with 1200 grit sand paper and it’s noticeably better except you can see the scratches in it, so I’ll need to find super fine sand paper.

 

My next lot of tests will be to sand down the primer as smooth as I can and see if that is ok. Or if I need to spray something on the primer that I can make smooth.

Any ideas are more than welcome!

 

These paints are really nice to work with though!! 

If you desire a flat silver then use a flat base I myself go gloss black thinned pretty(Mr.Hobby Leveling Thinner) well then polish it out.The finish up top on the silver is pebbly due to flat not being polished out enough .

[DocRob]

I built several planes with NMF finish over the years and some aspects are making a good `metal` look difficult. As you mentioned the base coat is of great importance. The shinier the result should be, the better has the preparation to be. High shine finish calls for gloss black base coats. My go to here is Tamiya LP gloss black. It sprays very fine and has a high gloss finish, when thinned properly with leveling thinner. If applied correctly, there is no need for polishing. AK has a great range of metal colors called Extreme Metal. Most of them spray very well, fine grained and with a realistic shine. There are more durable than Alclad II colors, which are a tad better, when it comes to high shine finishes. Beware off the AK Extreme Metal Black Base. This stuff never cures and stays tacky forever.
The application is another area of difficulties. High shine finishes are best, when carefully misted on in thin layers, until the blackness of the base barely vanishes. If you spray more, you loose luster. 
Another important step is preparation of the desired paint- and decal job. Most metal finishes are more or less sensible to masking, with Alclad being the worst that way. It pays to paint other colors before, if possible. Decaling with strong solvents can cause irritations in the metallic finish, as well as some clear coats. Generally, clear coats tend to lessen the shininess of the surface, even if it´s a gloss coat.

I hope that helps a bit and I link a build thread of one of my more recent NMF projects here, where the goal was to achieve a P-38 as shiny as possible and with additional rivets. I described my testing and methods of application a bit more detailed there
 

Cheers Rob

 

[CDW]

Search for my 1:32 P-51 thread to see how my NMF was done. 

 

Edited September 30 by CDW

[king derelict]

On 9/25/2024 at 9:23 PM, Lt. Biggles said:

I’ve also been keeping an eye on your build to see how you will do yours and any tips and tricks or dos and donts! 
Here is to us managing to get lucky and land a result we are both happy with on our first attempt 🍻

Your metal finish experiments are looking very good. And a lot of useful information from @CDW and @DocRob. I'm getting dangerously close to having to commit to a path with the Yak.

Alan

[Egilman]

Well, if you want the old oxidized aluminum finish, you can try it by hand.... (I know airbrushes are the "in" thing)...

 

I know old school, over a rattlecan flat black primer....

 

Depends upon the look you want, new and freshly issued or well used flightline trooper, combat vet...

 

The possibilities are endless brother...

[king derelict]

13 minutes ago, Egilman said:

Well, if you want the old oxidized aluminum finish, you can try it by hand.... (I know airbrushes are the "in" thing)...

 

I know old school, over a rattlecan flat black primer....

 

Depends upon the look you want, new and freshly issued or well used flightline trooper, combat vet...

 

The possibilities are endless brother...

Thank you EG. Your NMF work with the F104 is a standard reference read for me.

 wealth of options for NMF is impressive 

Alan

[Lt. Biggles]

Thanks everyone for all the tips and links! I’ve been going through them and will answer in the coming days. Things with my new job have been fast tracked so instead of waiting till next year I’ll be starting in just over a month! But I should finishing this project before then!

 

A little update.

been working on the cockpit and wheel wells and they are both coming along well.

 

 

Quite a fun part of the kit and is an effect that looks really nice too I think. 
 

A lot of debate about what was painted and when and what colours but this seemed to be a scheme that came up a lot and as far as I could tell fit in with the time period I’m building.

 

Dirtied up a little and I won’t add any more details or piping even though the extra details really look nice, they are just hard to justify for how little it will be picked up and looked at.

Now it’s just the cockpit to complete before the internals are done.

 

[Lt. Biggles]

Did a good amount on the cockpit.

seems like there is nothing to do after doing the insides of a b17! But there is something rewarding about detailing a cockpit.

 

Almost ready to close up.

The fit is really good! So good Infact that if you put something slightly in the wrong place then nothing goes together! Had to take one part off behind the seat and lower it by half a mil to get it to go together! But once in the right place it’s such a nice fit!

 

I’ll get the plane together pretty fast I think and spend some good time on the sanding and prep for painting stage!

I have a 3000grit sanding sponge now. So will prime and then use that to get super smooth.

 

For anyone that has done this kit… is there a way to make the prop spin or do I have to glue it? The usual piece at the back to lock it in place but free to spin isn’t a thing on the instructions! I’ll make one anyway as I was a spinning prop! Just really surprised me!

[Lt. Biggles]

Two fuselage halves have been sewn together!

A few PE details to add but it has come together well! Will have to think how best to deal with the seam along the nose so I don’t loose too much detail there.

 

The canopy will be in the open position so for painting I’ll attach one of the spare ones in the closed position and paint then remove it and attach the actual canopy at the end.

 

And regarding the prop, I’ve begun making an attachment so that it can spin! 

[Lt. Biggles]

Stage 2 of my NMF tests have been done. I wet sanded the mules primer smooth with my 3000 grit sponge paper and on one part did a heavy wet coat which seemed to get a touch of orange peel. And on the other side I did a few light coats. Which seemed to work well.

Here is the panel with light coats. (The panel is about 2cm long or just under an inch) I think instead of a 1:1 paint to thinner ratio next I’ll do 1:2 ratio or at least 1.5 thinner to 1 part paint. Thin coats are the way to go. Also the other day I noticed my airbrush needle was bent on the tip! So that might or might not affect my already $20 airbrush I’ve been using! I straightened it as best I could.

 

so I think I’m getting a grasp of the painting techniques and so now have to decide if a gloss underneath is needed. And if so why can’t I just use Tamiya x22 gloss clear over the polished primer? Even if I polish the gloss coat too? And does polishing it up make the paints not grip well? Or do the polishing marks have enough tiny groves for the paint to stick well?

Im running low on space on the mule. But can try my Tamiya gloss black underneath and polish that up! The joys of reading 1200 different NMF tutorials!

 

Anyway back to my actual build, I’ve made the prop able to spin and it spins really well and very smooth. It’s also ready for its weathering. I painted it all and just had to cut masking tape nice and accurately with many coats of yellow over a white base.

 

[Egilman]

57 minutes ago, Lt. Biggles said:

The joys of reading 1200 different NMF tutorials!

Yeah, I ran into that doing my research... Everyone's got an opinion, and theirs IS the way... {chuckle} And, because they posted in on the internet it is the "Best" way....

 

But, we have experienced veteran modelers here on MSW, and we know that there are many "Best" ways of doing things, find the one that works for you brother... I know you will...

[Lt. Biggles]

5 hours ago, Egilman said:

Yeah, I ran into that doing my research... Everyone's got an opinion, and theirs IS the way... {chuckle} And, because they posted in on the internet it is the "Best" way....

 

But, we have experienced veteran modelers here on MSW, and we know that there are many "Best" ways of doing things, find the one that works for you brother... I know you will...

Thanks mate! You are right, there are many opinions out there.

ill do one last round of tests using gloss black polished vs Matt grey polished and choose from there I think. I know for sure a super smooth surface is a real must. 
Thanks again for the good advice

[Lt. Biggles]

I’ve a plan after my final tests.

I’ll paint it gloss black, polish it and from there apply the super metallic 2 paints.

It is all primed and filled and given the first few coats of gloss black. I’ll give it some time and then do another coat before sanding it smooth and then polishing with Tamiya finishing polish. In my tests I can’t get it fully mirror like, but then I think it would need a wax or something to get that. I can get it pretty smooth though where the reflection is not bad and colours are pretty clear. I just found in my tests it didn’t really change the colour so much, but it did give it abit more depth of shine than from polished grey primer.

Keeping the coats really thin to try limit the amount of polishing needed at the end! And because the wings are painted a silver and not nmf they won’t get a full black coat it will just be this polished.
 

Also black is a really hard colour for me to air brush, always has been! It always speckles! But nato black… no issues! 
 

Im still debating if I fill in the wings with filler like the real one. I’ve a drawing of what panels to fill but not sure yet!

[Egilman]

1 hour ago, Lt. Biggles said:

Im still debating if I fill in the wings with filler like the real one. I’ve a drawing of what panels to fill but not sure yet!

I had this discussion with a kind soul a few months ago... it's a question of scale as in what your eye can see on a model...

 

Yes the wings of all P-51's were painted aluminum, aluminum colored lacquer paint, they would never shine like a mirror, not in real life, they would reflect light and other images near to them but no mirror finish...

The panel joints, we are talking about the riveted panel joints now were so close together that they didn't need filling and you wouldn't see them on the real aircraft even if the paint was stripped off and the wings polished to mirror finish like the airshow warbirds... So we need to know why the wing joints were filled and wings painted if the panel joints as built were so close....

 

Laminar Flow....

 

To get the maximum smooth airflow over the wings while maneuvering they incorporated Laminar Flow into the wings, what it was was tiny ports that release bleed air from the supercharger over the wing panel surface, this would cause the airflow to align with the wing surface reducing air turbulence over the wing and thence reducing inherent surface drag... So to get the smoothest surface possible the wings were epoxied with aluminized epoxy paint and not painted after that... This necessitated that the paper thin panel joints be filled which the epoxy paint did quite admirably.... 

 

How big were these joints in real life? a few thousandths of an inch, tolerance was 5-10 thousandths of an inch... 

There is no model at any scale under half scale that is going to represent the panel joints in any visible way... Yes the grain of the panel surface did come thru the epoxy paint and from that aspect you can have light reflectance variance in the individual panels from a distance but up close they look identical... In scale, they look good with different shaded panels but in real life that was seldom seen on an operational bird...

 

It was also only used on a few of the NA produced aircraft and the P-51 was the only aircraft produced in WWII that became operational with it... By the time Korea came around even North American did away with it as it just added production costs.. Besides the jet aircraft had more than enough thrust to push the airframe to almost supersonic speeds without it, the F-86 is a prime example as a transonic aircraft... (the Bell X1 is officially known as the first supersonic aircraft, but amongst the test pilots flying out of Muroc Field in the day, it's the F-86F that is recognized, unofficially of course, as the first aircraft to go supersonic without disintegrating)

 

And it had no laminar flow...

 

On a scale model, there is nothing to fill and besides, who's going to see it under the aluminized paint?

 

Of course there are those that will argue, but when actually discussing it they soon realize that the grooves created to represent the panel edges then filled on a model aircraft is a pure waste of time...

 

This of course is my sole opinion, but I've had this discussion numerous times and no one has been able to refute the facts yet... think about it for a minute before doing all that work, your creating a detail so you can paint over it and hide it like on the real aircraft?

 

We are smarter than that...

[Lt. Biggles]

4 hours ago, Egilman said:

To get the maximum smooth airflow over the wings while maneuvering they incorporated Laminar Flow into the wings, what it was was tiny ports that release bleed air from the supercharger over the wing panel surface, this would cause the airflow to align with the wing surface reducing air turbulence over the wing and thence reducing inherent surface drag... So to get the smoothest surface possible the wings were epoxied with aluminized epoxy paint and not painted after that... This necessitated that the paper thin panel joints be filled which the epoxy paint did quite admirably.... 

 

Thanks for the in-depth reply!

I didn’t know they  feed compressed air over the leading edge of the wing to reenergise the airflow and delay separation. That’s pretty complex for a 1940s plane! 
I just thought a laminar flow aerofoil was as smooth as possible to keep the flow laminar for as long as possible. Have you got any links to how they piped the compressed air and released it? It would be really interesting to learn about! That they were able to delay the separation point until 40% chord is pretty impressive.

 

Here are the plans I had seen with regards to the laminar section being puttied and smoothed out. And below that is a pic of my model with the wings having their panel lines which the real plane just didnt have and all the pictures I’ve seen shows a very smooth wing surface.

I was just on the fence if I should fill in the panel lines and also make my wing laminar too.

As this shows my wings covered in panel lines 

[Egilman]

Again it depends brother on what you want to depict with your model... If a wartime bird, fill them in smooth and paint... If an airshow warbird, all polished up then don't and use the panel lines for what they were intended for on the model... (creating shaded panels)

 

It's really a simple question of what you want it to look like, then build it to suit... But if your going for scale realism, then fill them and forget them... Like your pic clearly shows, they are not to be seen on a real combat aircraft...The wings were epoxy painted with aluminized paint and made ultra smooth...  And aside from a few experimental aircraft, it was the only one that NA did that made it into production...

 

It's really not worth it in my opinion... Only two ways to go for a detail that no one will ever see whichever way you decide to do it...

 

AS far as the details on the Laminar Flow Wings I'll have to dig around for my Dash-1's on it, and they are currently in the attic... But if you really want the info brother, I see what I can find...

[Danstream]

2 hours ago, Lt. Biggles said:

I didn’t know they  feed compressed air over the leading edge of the wing to reenergise the airflow and delay separation. That’s pretty complex for a 1940s plane! 

I am following with interest, I am probably the kind soul that enjoyed a discussion with @Egilman about this subject 🙂. I am sorry, but, with all respect, I need to comment few details about the description above, for the sake of precision. Definitely, aircraft from 1940 did not have the blowing systems described above. In addition, the blowing, sometimes referred as 'supercirculation' is not intended to reduce skin friction drag, but its purpose is to delay flow separation (hence to reduce the so called form or pressure drag) and not to maintain laminar boundary layer. Few example that I can easily remember that had this system (at the leading edge of the flaps) were the F-104 and the British Buccaneer, both having extremely high wing loading and the need to fly at high angle of attack at low speed. At very high speed, or at cruise, the angle of attack is very small and the blowing is not needed.

 

Coming back to the Mustang, it had wings equipped with so-called 'laminar wing sections' that are sections studied by NACA displaying a shape that produced a favorable pressure profile which, in turn, delayed the natural transition from laminar to turbulent boundary layer. These were the 6-digits designation profiles like, for example, the NACA 654-415. North American did not implement strictly a NACA section but rather an in-house developed profile obtained by the same mathematical theory that NACA used for their 6-digits. The results and the mathematical theory were published by NACA and industries were made aware of them. The reduction of surface drag was completely passive and it was intended to increase the range or the top speed (which are closely interlinked).

 

A bit of theory now. When air (or any fluid) flows over a smooth aerodynamic surface, it always starts as laminar. For high speed, after a very short distance, the boundary layer switches from laminar to turbulent, but this doesn't imply that the flow is detached. Flow is still attached, it follows the surface, but within the boundary layer, very close to the surface (for high speed we are talking of several mm) the flow doesn't follow parallel, ordered streamlines. With laminar sections, the region were the flow is laminar is stretched further back towards the trailing edge. The larger proportion of laminar over turbulent results, everything else being the same, in a smaller skin friction drag.

(from: NACA Quest for Performance: The Evolution of Modern Aircraft, very interesting document, with little math that can be found on line)

 

However, laminar boundary layers have also their negative points and one of the most important is that the flow is more prone to detach from the surface. Turbulent boundary layers are instead more robust and follow better the surface (see the paradox of the golf balls that with dimpled surface fly further than smooth balls). When the flow detaches from the surface, the form drag greatly increases. Sometimes, the laminar B.L. detaches and shortly after reattaches to the surface with a turbulent B.L.

 

Often, it is desirable to have a turbulent B.L. because it follows better the curved surface of fairings (as in a golf ball) and rear portion of wings, especially in the areas where ailerons are located (I am sure you can remember aircraft having vortex vanes along the leading edge in front of the ailerons). The matter is governed by the numerous trade-offs and compromises that are at the base of the system design.

 

In conclusion: Mustang had laminar sections to increase range and/or top speed. They worked with low angle of attack (or low lift coefficient which is the same thing). To work well, the surface of the wing needed to be smooth (see also included plot) and this was the reason for puttying rivets and gaps. However, it is also reported that small imperfections (like smashed insects or paint chipping) were responsible for having areas where the laminar B.L. switched to turbulent B.L. partly vanifying the purpose of these profiles.

 

I am sorry for this long explanation, but the subject is not completely trivial and it is difficult to explain it in a succinct way, but a lot of sources are available on the web. I am particularly passionate about this subject that was part of my studies. I could provide reference textbooks to anyone interested to go deeper and  I will be glad to discuss any comment or clarifications you might have.

Best regards,

Dan

 

Edited October 9 by Danstream

[realworkingsailor]

3 hours ago, Lt. Biggles said:

Thanks for the in-depth reply!

I didn’t know they  feed compressed air over the leading edge of the wing to reenergise the airflow and delay separation. That’s pretty complex for a 1940s plane! 
I just thought a laminar flow aerofoil was as smooth as possible to keep the flow laminar for as long as possible. Have you got any links to how they piped the compressed air and released it? It would be really interesting to learn about! That they were able to delay the separation point until 40% chord is pretty impressive.

 

Here are the plans I had seen with regards to the laminar section being puttied and smoothed out. And below that is a pic of my model with the wings having their panel lines which the real plane just didnt have and all the pictures I’ve seen shows a very smooth wing surface.

I was just on the fence if I should fill in the panel lines and also make my wing laminar too.

As this shows my wings covered in panel lines 

I feel compelled to jump in, if you don’t mind, with a small factual (fun?) tidbit. The prototype photo you posted is in fact a P-51H model, not a P-51D. Aside from other design changes, it used an entirely different NACA wing profile than the “D” model, and can be most easily recognized by the straight leading edge.

 

Andy

[Canute]

Nice aero discussion. You can add the F-4 Phantom, with it's Boundary Layer Control system on both leading and trailing edge flaps.The landing speeds were reduced with this system, especially critical for landing aboard ship. Land based F-4s had the system, too. When the F-4E model was converted to Leading Edge Slats, the internal hardware was merely capped off and left in place. Our landing speeds were bumped up about 10 knots. Not sure about the USN J model conversion. The slats added about 1,500 pounds to our empty weight.

[Danstream]

@Canute, thanks for your first hand piece of experience! In my note, I was focused on drag reduction, but of course the most significant improvement achieved by of B.L. control by blowing is to keep the flow attached at very high angle of attack making possible flying at low speed, lower than those possible without it, as you reported. But I am blown off at knowing that the slat system costed as much as 1,500 pounds!!

Cheers,

Dan