Ambrosini by Montanamotor

[GregP]

Hi Montanamotor,

I have read your posts about the the proposed Ambrosini Dardo (SAI-403). I have a concern I wanted to bring up.

Both the SAI 207 and 403 used Isotta-Fraschini Delta engines of 750 HP. The 207 used the Delta RC.35 or RC.40 with a Piaggio 3-bladed prop. the 403 used teh Delta RC.21/60, also with a Piaggio prop.

You are contemplating using a Continental and you want 1000 HP.

I will remind you of someting in Aerodynamics. An increase in power without a corresponding change to the tail areas and maybe the wing can result in a significant loss in stability.

If you flat-rate the engine and confine yourself to 750 HP, the handling should be the same as a stock aircraft, but actually using the 33% increasing in power could result in uncontrollable rolling, yawing, or both ... you will be flying as a TEST PILOT.

Recall the P-51D lost significant stability with increrases in power, as have many aircraft. Most WWII fighters gained weight and power over their development, and their flying qualities suffered significantly. Read the proceedings of the 1944 Fighter Conference. This exact subject is discussed.

I think you'd best think carefully about using more than 750 HP (559 kW) without visiting the design calculations and limitations ... and making changes as indicated by a one third increase in power, even if you have to pay a professional aerodynamicist to do it. If you are set on a replica, I'd build either the SAI 207 or 403, whichever has the most fin and rudder area, and I'd limit the power to 750 HP until I had over 100 hours on the airframe and had a fully-explored flight envelope at 750 HP before trying the 1000 HP available.

Just a piece of unasked-for advice, but we'd like to see a flight report, not an accident report!

Best of luck to you! ... and please keep us informed of progress.

[montanamotor]

Thanks for your good advice, GregP.

I really appreciate it. I promise, I'll approach this topic like a cat approaches the mouse: Easy, eaaaasyyyyyy...!

About directional stability: Yes, and no. Yes: You are right, directional stability IS a subject to regard and watch, if one is going to increase the aircraft-engine's power output.

But the examples you are giving are misleading a bit. As far as I am informed, the P 51's directional instability occurred only, after it had cut down it's rear deck for use of the round-vision-bubble-canopy.

The same was to be watched with the P 47, which had suffichient directional stability even with 2800 instead of it's initial 2000 HP-engine - but only, as long as it retained the "RAZORBACK"-fuselage. As soon as the cut-cown deck and the bubble-canopy were introduced with the P 47 D, instability occured, which had to be regained by use of an additional dorsal fin ahead of the vertical tail (same fix for Mustang).

The raised deck of most early fighters in WWII contributes significantly to directional stability. And a raised deck the Dardo HAS - and will retain.

The one single type of plane with raised deck, which definitely NEEDED a larger fin later in the war, to overcome the additional rotational forces of it's engine being tuned to TWICE it's basic power, was the BF 109, which from 109 G10-onward was given a substantially larger vertical fin.

But this is also largely owed to the fact that, the basic vertical fin-and-rudder of the Bf 109 was EXTREMELY small from start. Remember some shots from the film "Battle of Britain" with "Messerschmitts" standing on the ground for servicing? The vertical tailfins of the Buchons used there, which were based on small-tailed G6's, are SMALLER than a man standing besides this tail is. Willy Messerschmitt was nororious for giving his planes very small fin and rudder surfaces, to reduce drag as much as possible (see ME 210...).

This small tail in the Bf 109 is a VERY uncommon feature for fighter planes. I remember photographs of other fighter planes with people standing near the tail. Those fins are almost ALWAYS MUCH HIGHER than an average person is.

The size of the Dardos fin and rudder-areas resemble very much those of the P 51 Mustang - and will of course retain the raised upper deck of the fuselage. So, increasing power by 1/3rd should not be too much of a problem - if at all.

And finally, an aeroplane can always be flown with it's engine throttled back a bit, also (provided, it is strong enough from start).

But I promise, I will keep things under control. I am NOT going to lose my head by losing my tail...

Cheers!

Montanamotor

[GregP]

Hi Montanamotor,

I feel better about your Dardo, and I know about the loss of stability due to changing from turtledeck to bubble canopy. I also am aware that most WWII fighters suffered reduced flying qualities with increasing weight and power. The subject has been rather well explored.

I have little knowledge of the Dardo in comparison to the mainstream American fighters, and is is possible your installation will not weigh more than original the Isotta-Fraschini installation.

Again, good luck! :)

[Lightning]

Hi montanamotor,

Quoting you:
quote:As soon as the cut-cown deck and the bubble-canopy were introduced with the P 47 D, instability occured, which had to be regained by use of an additional dorsal fin ahead of the vertical tail (same fix for Mustang).
In addition to the dorsal fin, the latest P-51Ds, the TF-51D, and the P-51H, had the vertical tail made higher for the same reason.

Regards,
Lightning

[montanamotor]

Lightning,

you are right about the Mustang. I think I remember that, one can distinguish F8F-Bearcats of the latest lot from the earlier series by it's substiantially higher tailfin, also.

The Bell P 63 King Kobra gained more and more fin area during her development, too - to an extend, where one might find the tail-units of the latest King Kobras - well: Somewhat overengineered, to say the least...

Bell allways quoted, they would only respond to test-pilots and frontline reports (by french and russian pilots), claiming for this plane featuring an indifferent feeling during firing - "unstable gunplatform" was the mostly-used term, I think - with the King Kobra.

Well: Maybe this, at least, was more contributed to inexperience and nervous kicking-about on the pedals by the pilots, rather than to aerodynamic insufficient directional stability...?

Reminds me of a certain, well-known american attitude: "If big is good, then bigger is better!"

I wonder if this goes for any tail... - says

Montanamotor [:I]

[Lightning]

Quoting montanamotor:
quote:I wonder if this goes for any tail...
Hmmm [}:)]

[Lightning]

Hi montanamotor,

Quoting you:
quote:
The Bell P 63 King Kobra gained more and more fin area during her development, too - to an extend, where one might find the tail-units of the latest King Kobras - well: Somewhat overengineered, to say the least...

This is very obvious when you compare the vetical tail of the P-63 with that of the earlier P-39. In fact, one version of the P-63 had the tail extended below the elevator.

Regards,
Lightning

[Kutscha]

quote:But the examples you are giving are misleading a bit. As far as I am informed, the P 51's directional instability occurred only, after it had cut down it's rear deck for use of the round-vision-bubble-canopy.

The razorback Mustangs had the same stability problem as the bubbletops. The small fillet was added to them as well.

[GregP]

I'll forego the obvious comments on any tail being better when it is bigger.

Let's just say that enough tail is needed for whatever purpose you are trying to fulfill. There is nothing worse than insufficient tail ... unless it might be tail disease resulting is a broken tail.

I suppose a broken tail might be worse than insufficient tail.

[Lightning]

Hi Greg,

That's some tale you tell about tail!

One way to look at it is that, depending on circumstances, There's no such thing as too much tail or too much ammo!

Regards,
Lightning

[montanamotor]

...or to much horsepower. :D

QED!

Montanamotor

Aaaah - cheers! That was, what I was missing.

[GregP]

Upon further consideration, I think the worst position to be in is no tail at all. ;)

Flying wings were tough to figure out for most designers, and complete lack of tail was one of the issues to sort out ... it takes a special aircraft to put up with no tail at all. Doing without tail is not for the faint of heart.

On to other tales of ww2 stuff with nothing to do with tail!

Lest we forget, many raids were flown on factories that made balls for ball bearings, and Germany found it impossible to continue the struggle without sufficient balls to go around.

But, that's another tale! :D

[montanamotor]

Hi, Folks!

To give you a better impression of what will happen in the next years concering the "Dardo Nova"-project, I found two very interesting websites, able to identify the "what's" and "how's" of a wooden fighter airplane with an aircooled inverted engine with some more specific detail to you:

See http://www.siersflight.com/Index.html for the aircraft, and http://www.moraviation.com/ for the engine, to get a better "feel" for it.

GregP, I'll send you a few more pics of the making of the aircraft from the net via email, as I would like to misuse you for loading them up to TGPlanes, if you will. Would you...? :D

Put the plane and the engine together in your own private, brain-based 3D-simulator, and you will get a rather detailed impression of what will happen, soon.

GregP, thanks for the link to the Continental V 1790! I have noted it and will put it in good use. By the way, a tank-engine isn't so badly suited for use in an aircraft AT ALL, as, for example, both the DB 601 as well as the Merlin, then named Meteor, were used for driving heavy battle-tanks in their days, too. Today, lots of Meteor-engines from tank-driving-origin are being recovered and reengineered for use as "real" Merlins, again.

So it seems that, tank-engines and fighter-engines bear quite a useful lot in common, dont they...?

GregP, another potential source for Continentals I could Identify as the company which sells ISRAELI army surplus to the world: See http://www.sibat.mod.gov.il/land/pritim01.htm . The crank, the single cylinder and some of the accessiories depicted there, together with the Continental in the crate are all spares of same type of engine. Aaaah - there's LOT's of fat to cut off that crankshaft!

Well, as you may say, the actual political situation in the Near East may rather not be too well suited to go there and make some deals with the army. Yep! You are right. But what goes for me, goes for anybody else as well. So, as long as the unrest at the eastern end of the Mediterranean Sea persists, there is a good chance that, thh engine and parts may remain availlable for some time in the future, still - until further notice.

I'll keep you informed. But first, I'll go for a big bowl of icecream now!

Cheers!

Montanamotor

[Lightning]

Hi Greg,

Quoting you:
quote:
Lest we forget, many raids were flown on factories that made balls for ball bearings, and Germany found it impossible to continue the struggle without sufficient balls to go around.

That is probably what Bet Midler had in mind when she sang:


"Hitler had one big ball

Goering had two, but they were small

Himmler, had something sim'lar

And Goebels had no balls at all"


This must have been the result of the Schweinfurt raid! :D

Regrets,
Lightning

[GregP]

I'd best leave the ball bearing stuuf alone or I could wander into completely unwarranted territory ...

Meanwhile, I wish Montanamotor the BEST as he tries valliantly to get a Dardo airborne from scratch. I wish I could help! I LOVE working on aircraft and getting things running.

Michael, if I can help in any small way, please let me know. Knowing that a Dardo may fly in the future is enough for me. When it does, I want pics! ... and GOOD ones. :)

[montanamotor]

Greg, check your emails!

CU,

Montanamotor

[montanamotor]

Hi, Friends.

See this:

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/eyore2.jpg

The wooden Barracuda. Cute, ain't it?

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/eyore4.jpg

Still cute.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Rib-Spar.jpg

Jep: Wing-ribs - exactly like bulding model-airplanes. Only slightly larger...

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Rudder.jpg

A tale-telling tail... :D

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/WingRib.jpg

Wing-ribs - not spare-rips.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Spar.jpg

The main wing spar - nor quite bullet-proof - but almost...

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/StabSpar.jpg

Horizontal stabilizer spar. You can build them at you kitchen-table, can't you.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/eyore5.jpg

The Barracuda's cockpit. You can also build it with a pair of sticks.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/m337ce.jpg

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/337c.jpg

The Moravia-LOM-engine, which I would highly recommend for the Barracuda.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/spit1.jpg

And this is how the engine's installation in a plane looks like. This one is in a wooden Spitfire-Replica. Not bad, also. But not the real McCoy...

Well, as I said already: This is NOT a Dardo Nova. But you can get a glimpse of how it might be, to build one. No witchcraft neccessary here, really. If you can build a big-size r/c-model from wood, you can build this one, too. And if you can build this Barracuda - a Dardo Nova would only be the next logical step to go.

See you later.

Cheers!

Montanamotor

P.S.: GregP and RT - I've done it! At last! Jeeeeehaaaaaa!:D

[GregP]

Nice post montanamotor. I like the barracuda.

The LOM engine looks like a great candidate to use to make an inverted V-12. All it needs is a new crankcase and crankshaft ...

Anyway, the wood must be carefully sealed to prevent damage by moisture, as I'm sure you know.

Please build the Dardo or the SAI 207, which was essentially the same aircraft without armament. Fitting fake armament would cost a bit of speed, but using fibergalss or lightweight replicas would not add too much actual weight, and there would be no need to build any weight into the armament bays.

Best of luck! :)

[Ricky]

quote:Originally posted by montanamotor

The wooden Barracuda. Cute, ain't it?

Certainly a lot more cute than another airbourne Barracuda I could mention...

Lovely pics Montanamotor, and very interesting. Many thanks!:)

[montanamotor]

Yeah,

I love to hear you say that.

GregP, Your idea has come to the right person's ears and minds already. See:

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/sagitta.jpg

The Walter-LOM Sagitta from 1935-origin. 12 cylinders, 12 Liters of displacement, 550 HP.

It's all there...

Besides: In power, wheight and shape, it's practically identical to the Argus As 411-(Renault 12-00)-engine. I've found out that, there are still HUNDREDS of these Argus-Renaults on the market, if not in the air.

See this:

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Argus3.jpg

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Argus2.jpg

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Argus1.jpg

Once I started looking for an aircooled, inverted aero-engine, with the faint hope, there might still be some out there to be found, to serve my purposes. But now, I stumble over them, wherever I go - HELP...! :)

Maybe - MAYBE! - I'll resort to the Argus as a powerplant for the Dardo Nova, or like. That is: At first... :D

Cheers!

Montanamotor

[Lightning]

Hi montanamotor,

I'm [u]totally</u> impressed! Woderful postings! I wish you the very best of luck in your endeavor (although I think your obvious know-how, not luck, will win the day).

Regards,
Lightning

[Mark J]

Yeah me to, all the best for this great project, I'll be watching with interest

cheers

[montanamotor]

Guys,

I won't let you down. Promised. "Trust me. I know what I am doing!"...

Cheers!

Montanamotor

[Paolo Tagliaferri]

Did u managed to post images? Or I have to post the ones I've got in my mail?

[montanamotor]

Hi, Taglia!

No, thanks. Done already. Works fine now.

I had to sign in for "Photobucket" first. After I managed this, now it's no problem anymore to load pictures up here.

One tip for all "Photobucket"-users and watchers of respective pictures in TGP: It looks like, the access to the photographs depicted by photobucket is limited to a relatively short time. The links seem to expire within 2-3 weeks or so, as I have noticed elsewhere in this forum, already.

So, if you are interested in preserving any pictures you see here in TGPlanes more often, you should load them down to your own computer's harddrive.

Cheers!

Montanamotor

[Lightning]

Hi montanamotor,

Quoting you:
quote: "Trust me. I know what I am doing!"...

Now I've got you! I know who you are! In real life you're my hero--SLEDGE HAMMER!!!

Keep up the good work, Sledge. :D

Regards,
Lightning

[Kutscha]

montana,

it is not so much that the access to the photos is time limited but that one is only allowed so many items. That is my case (50 items), anyways. When I upload a new item I will go through and delete some old items, usually to make room.

[montanamotor]

Lightning,

"...and I'll name the first Dardo Nova "Susi", too..."

:D:D:D

Check, Kutscha. Didn't know that.

Cheers,

Montanamotor

[Lightning]

Hi Kutscha,

Quoting you:

quote:The razorback Mustangs had the same stability problem as the bubbletops.

The term "razorback" does not apply to the P-51--in any model. The correct term for the non-bubble-canopy Mustangs--the P-51A/B/C--was "flush canopy."

The P-47, up through the early "D" variant, also had a flush canopy, but the fuselage formed a sharp ridge along the spine running back from the cockpit to the tail. It was this feature that led to the term "razorback."

Regards,
Lightning

[hesham]

What do you know about Ambrosini type-25 aircraft ?.

[GregP]

I am not familiar with the Ambrosini Type 25 at all. I'd love to see a pic and get some specs! :)

[Lightning]

Hi Kutscha,

In reading back over this topic,I noticed that you wrote:
quote:The razorback Mustangs had the same stability problem as the bubbletops. The small fillet was added to them as well.
Are you talking about the dorsal fin as found on later "D" and subsequent P-51 variants? I have looked at a lot of photos of earlier-model P-51s, and I don't see any with this dorsal fin.

You use the word "fillet." Do you mean something other than this dorsal fin? Maybe I'm missing something.

Regards,
Lightning

Added by edit:

Guess what? I found a photo of a "B" with a Malcomb hood and what appears to be a dorsal fin. The picture is from a front-quarter angle, so it's not really clear, but it sure looks like it.

In reading up on this feature, I found references to suggested retrofitting of "B/C" variants, but no mention was made of factory installation. Since the early "D"s did not have it, I would assume that the late-production-run "B/C"s also came off the assembly lines without it.

The reason given in one source for the addition of this fin was that, without it, stresses on the horizontal stabilizer during snap-roll type maneuvers could cause structural failure. I know that it improved directional stability on the "D" that was lost because of decreased side area due to cutting down the rear fusellage to allow installation of the bubble canopy.

Since this recommendation was for "D"s as well as "B/C"s, it was obviously made after the "D" was already rolling off the assembly lines. This leads me to believe that any dorsal fins added to variants earlier than the "D" were added in the field or at a modification depot.

Your thoughts?

Regards,
Lightning

[hesham]

Hi,

what do you know about Ambrosini-25 aircraft ?.

[montanamotor]

Hello, Hesham,

nice to meet you. I must admit that, I couldn't find much on the Ambrosini 25. All I found was, that there was a fighter plane under development at Ambrosini in 1936, that bore the designation "Ambrosini 25". That's all, I am afraid.

No pictures and no data availlable - yet, perhaps. Maybe our italian friends do know a little more about this Ambrosini 25-ghost?

Dogwalker, what's your opinion?

Cheers!

Montanamotor

[hesham]

Hallo Montanmotor,
thank you,and please anther question to complete all about
Ambrosini aircraft,
can you identify SAI 4,SAI 5 and SAI 6 aircraft ?.

[montanamotor]

Hesham,

please look at this most comprehensive compilation on Ambrosinis by our most-beloved "Romantic Technofreak" and others:

http://www.tgplanes.com/Public/snitz/topic.asp?TOPIC_ID=574

I think, even in well-assorted bookstores, you'll have to search hard to find something better on Ambrosinis than this.

What makes you so interested in Ambrosinis? I am asking, because I am extremely fond of those exquisitely build planes myself.

I know there were quite a few civilian types of general aviation-Ambrosinis around, too - but sadly so, I don't know much about them, and I didn't find too much about them in a short time. Try "GOOGLE pictures" - maybe this can be of some help to you, too.

Hoping to hear from you soon,

Montanamotor

P.S.: Also try these links:

http://www.geocities.com/fiap_ambrosini/

http://www.airwarfareforum.com/viewtopic.php?p=31605#31605

http://avia.russian.ee/air/italy/a_ambrosini.html

Cheers!

[hesham]

You are wright Montanamotor,but there were many of this

company aircraft unknown,such as SAI-401 and SAI-402 projects.

[GregP]

The post above about the "fillet" is interesting.

An extension to the vertical tail abpve the fuselage is called a dorsal fin or a dorsal spine. A fin below the fuselage is called ventral fin or spine.

A "fillet" is a rounded piece of metal or other material attached to both the fuselage and the wing to "round" the 90° intersection between the wing and fuselage in order to reduce interference drag. It can also be applied to a rounded piece of metal or other material that is used to round the intersection between the horizontal or vertical tail and the piece of fuselage where it joins.

Think of the LARGE fillets on the P-40.

The intent is to reduce the interference drag caused by 90° intersections and fillets are also used on wing tips to round the junction between a winglet and the wing. Round and aligned with the local ariflow is the least interference drag.

A dorsal fin or spine is an additional area added to the tail of a typically piston fighter when the power has been increased in order to maintain the stability (usually directional stability, or yaw) that is usually degraded when the power is increased while the control surfaces have not changed in size to help accommodate the power increase.

Almost all WWII fighters suffered degraded flying characteristics as they matured due to increased weight and power. There are VERY few exceptions other than the Yakovlev and Lavochkin fighters of the Societ Union. The last Yaks and La's flew VERY well for a piston fighter when most Western Air Forces had abandoned pistons for jets ... which, coincidentally, also needed dorsal fins or spines to maintain directional stability as more powerful jet engines began to be fitted to existing airframes, as in the F-86H (in which Joseph McConnell was killed in fight test). As the pwoer increased, the fin area was increased, too. The most nociceable increase was in the North American F-100. After George Welch was killed doing a "Sabre Dance," the F-100s were grounded until the vertival fin could be made taller to increase directional stability. All subsequent Super Sabres had the larger fin.

Look at the vertical fins of the last Seafires and Spitefuls in comparison to the wartime Spitfires and you will see a corresponding increase in fin area due to increased power.

The only aircraft I can think of that did NOT require major increases in fin area with power were aircraft such as the Fairey Gannet and Breguet Alize that had counter-rotating props to help zero-out engine torque.

If counter-rotating props were fitted, there was no need for inceased fin area to fight extra torque. The fin only had to be big enough to fly the plane under normal conditions and to counteract the torque available when one of the counter-rotating props failed, leaving a plane flying on half power with centerline thrust. That only required a modest vertical tail and rudder ... perhaps with the exception of the Westland Wyvern, which ad an enourous vertical tail and rudder area.

A fellow by the name of Roy Lopresti materially decreased the drag on the Monney line of US civial aircraft using fillets and other forms of aerodynamic "cheating" over the last 20+ years to the point where the latest Mooneys are among the fastest planes in the civil world on modest horsepower. The latest Mooney can cruise at 235 knots on 270HP while seating 4 people. Not bad!

The Douglas Skyshark was a disaster that led to the Shyraider which, though of WWII vintage technology, could deliver a bomb load better than a WWII B-17 flying from London to Berlin.

You will notice the Skyraider has a VERY large dorsal fin that fares into the vertical tail, kind of like a miniature B-17 fin. Personally, I wonder why they never simpy made the vertical tail larger as power increased.

The answer probably lies in production line interruptions. It is far easier to add a dorsal (or ventral) fin than to change the vertical tail, and they both accomplish the same task.

[Groggy]

quote:Originally posted by GregP

The post above about the "fillet" is interesting.

An extension to the vertical tail abpve the fuselage is called a dorsal fin or a dorsal spine. A fin below the fuselage is called ventral fin or spine.

A "fillet" is a rounded piece of metal or other material attached to both the fuselage and the wing to "round" the 90° intersection between the wing and fuselage in order to reduce interference drag. It can also be applied to a rounded piece of metal or other material that is used to round the intersection between the horizontal or vertical tail and the piece of fuselage where it joins.

Think of the LARGE fillets on the P-40.

The intent is to reduce the interference drag caused by 90° intersections and fillets are also used on wing tips to round the junction between a winglet and the wing. Round and aligned with the local ariflow is the least interference drag.

A dorsal fin or spine is an additional area added to the tail of a typically piston fighter when the power has been increased in order to maintain the stability (usually directional stability, or yaw) that is usually degraded when the power is increased while the control surfaces have not changed in size to help accommodate the power increase.

Almost all WWII fighters suffered degraded flying characteristics as they matured due to increased weight and power. There are VERY few exceptions other than the Yakovlev and Lavochkin fighters of the Societ Union. The last Yaks and La's flew VERY well for a piston fighter when most Western Air Forces had abandoned pistons for jets ... which, coincidentally, also needed dorsal fins or spines to maintain directional stability as more powerful jet engines began to be fitted to existing airframes, as in the F-86H (in which Joseph McConnell was killed in fight test). As the pwoer increased, the fin area was increased, too. The most nociceable increase was in the North American F-100. After George Welch was killed doing a "Sabre Dance," the F-100s were grounded until the vertival fin could be made taller to increase directional stability. All subsequent Super Sabres had the larger fin.

Look at the vertical fins of the last Seafires and Spitefuls in comparison to the wartime Spitfires and you will see a corresponding increase in fin area due to increased power.

The only aircraft I can think of that did NOT require major increases in fin area with power were aircraft such as the Fairey Gannet and Breguet Alize that had counter-rotating props to help zero-out engine torque.

If counter-rotating props were fitted, there was no need for inceased fin area to fight extra torque. The fin only had to be big enough to fly the plane under normal conditions and to counteract the torque available when one of the counter-rotating props failed, leaving a plane flying on half power with centerline thrust. That only required a modest vertical tail and rudder ... perhaps with the exception of the Westland Wyvern, which ad an enourous vertical tail and rudder area.

A fellow by the name of Roy Lopresti materially decreased the drag on the Monney line of US civial aircraft using fillets and other forms of aerodynamic "cheating" over the last 20+ years to the point where the latest Mooneys are among the fastest planes in the civil world on modest horsepower. The latest Mooney can cruise at 235 knots on 270HP while seating 4 people. Not bad!

The Douglas Skyshark was a disaster that led to the Shyraider which, though of WWII vintage technology, could deliver a bomb load better than a WWII B-17 flying from London to Berlin.

You will notice the Skyraider has a VERY large dorsal fin that fares into the vertical tail, kind of like a miniature B-17 fin. Personally, I wonder why they never simpy made the vertical tail larger as power increased.

The answer probably lies in production line interruptions. It is far easier to add a dorsal (or ventral) fin than to change the vertical tail, and they both accomplish the same task.


Hi ,

Aircraft Carrier Hanger limitation in hight?

[hesham]

Hi Montanamotor,

can you tell us about all Ambrosini series aircraft ?.

[Lightning]

Hi Greg,

Quoting you:
quote:A "fillet" is a rounded piece of metal or other material attached to both the fuselage and the wing to "round" the 90° intersection between the wing and fuselage in order to reduce interference drag. It can also be applied to a rounded piece of metal or other material that is used to round the intersection between the horizontal or vertical tail and the piece of fuselage where it joins.

That is what I was talking about when I asked about Kutscha's use of the word "fillet." The early tail buffeting (it wasn't tail "flutter" nor was it caused by compressibility) on the P-38 was caused by disturbed airflow at the junction of the wing center section with the central "pod." The fix was the addition of a fillet at this location.

Regards,
Lightning

[montanamotor]

Hesham,

for the moment not, I am sorry. Later in the year I will very likely be able to conduct a deeper research. But actually, I don't know much more about Ambrosinis than is to be found here at tgplanes and by Google.

Again: What makes you so interested in the Ambrosinis, Hesham? Have you found a forgotten example of which in the Aegyptian Desert, perfectly preserved and "mummyfied" by dry desert winds and waiting for your "magic" service to "resurrect" it back to flying condition...? [8D]

I'll keep you informed. I promise.

Cheers!

Montanamotor

[Montana]

quote:Originally posted by montanamotor

Hi, Friends.

See this:

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/eyore2.jpg

The wooden Barracuda. Cute, ain't it?

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/eyore4.jpg

Still cute.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Rib-Spar.jpg

Jep: Wing-ribs - exactly like bulding model-airplanes. Only slightly larger...

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Rudder.jpg

A tale-telling tail... :D

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/WingRib.jpg

Wing-ribs - not spare-rips.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/Spar.jpg

The main wing spar - nor quite bullet-proof - but almost...

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/StabSpar.jpg

Horizontal stabilizer spar. You can build them at you kitchen-table, can't you.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/eyore5.jpg

The Barracuda's cockpit. You can also build it with a pair of sticks.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/m337ce.jpg

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/337c.jpg

The Moravia-LOM-engine, which I would highly recommend for the Barracuda.

http://i111.photobucket.com/albums/n149/montanamotor/Barracuda%20pics/spit1.jpg

And this is how the engine's installation in a plane looks like. This one is in a wooden Spitfire-Replica. Not bad, also. But not the real McCoy...

Well, as I said already: This is NOT a Dardo Nova. But you can get a glimpse of how it might be, to build one. No witchcraft neccessary here, really. If you can build a big-size r/c-model from wood, you can build this one, too. And if you can build this Barracuda - a Dardo Nova would only be the next logical step to go.

See you later.

Cheers!

Montanamotor

P.S.: GregP and RT - I've done it! At last! Jeeeeehaaaaaa!:D


UPDATEUPDATEUPDATE!

Folks,

just to share some pictures on wooden aircraft with you, which have reached me only recently, see this:


Barracuda construction 3d-Autocad: You can't see it any better... [:p]

http://i111.photobucket.com/albums/n149/montanamotor/8111.jpg



Barracuda airframe close-up: Buy some Balsa and start carving, folks! [:o)]

http://i111.photobucket.com/albums/n149/montanamotor/withcowling-1-27-07.jpg


Ambrosini SAI S.7 Supersette fuselage - not soooo far from a Barracuda, is it? :D

http://i111.photobucket.com/albums/n149/montanamotor/SAISuperS.jpg



How it works: This is where your survival relies on, guys. You better be nice to it. Every day. ;)

http://i111.photobucket.com/albums/n149/montanamotor/1one.jpg



Nay: No Dardo, no Supersette - a 207: Nice picture, anyway. Watch the engine mount - nice, but: There's nothing a Bf 109-mount can't improve... :D

http://i111.photobucket.com/albums/n149/montanamotor/Dardo5.jpg

CHEEEEERS! [8D] :D

Montanamotor (390+X)

[Trexx]

How many guns? ;)

[GregP]

Hey Montanamotor!

Check this link. It is the flight manual and parts manual for the S.7! Go for it. Cheap. :)


http://www.flight-manuals-on-cd.com/AmbrosiniS7.html

[Montana]

quote:Originally posted by GregP

Hey Montanamotor!

Check this link. It is the flight manual and parts manual for the S.7! Go for it. Cheap. :)


http://www.flight-manuals-on-cd.com/AmbrosiniS7.html


This is one cool hint!

I'll be after it right now!

Yeeeeeehaaaa! :)

Montanamotor (390+X)