Carving Mustang Air Scoops, 19 photos

LAST EDITED ON Feb-13-04 AT 05:23 PM (CDT)
 
In conversations with semi-scale Mustang builders, I frequently hear the complaint that the air scoop is too difficult to carve. Well it is a bit intimidating if you start with a 4"x4"x4" block and do the Leonard da Vinci thing of carving away everything that doesn't look like a Mustang inlet air scoop.

I'm thinking of writing a construction/technique article for Stunt News about how this might be more simply done. I'm posting this in the realization that Stunt News reaches many more readers than Stuka Stunt. The article would be nicer with individually captioned photos and some text. still, I thought I'd run it by here first for reaction.

Basically, my construction is made from sheet balsa and several sizes of square balsa sticks. It weighs 4 grams. One interesting thing about this type of construction is that it must be carved from the inside out. Also, it has to be sanded inside and primed before installing a bulkhead about 3/4" inside the opening. Final carving is done with a flashlight reference for wood thickness. Once the bulkhead is in place you just can't get to the inside to smooth the interior. Of course, similar techniques can be used to build fancy cowls.

Comparing the last two photos, it looks like my new scoop inlet is deeper than the real Mustang photo. Partly, it is the camera angle. The real Mustang photo is more head on. Also, my semi-scale scoop is very near scale in the side view but the whole airplane is narrower than scale. So, the scoop isn't too deep, it is too narrow. Still, it looks correct from inside the circle where I'll be viewing it.

What do you think?

This would truly make a most excellent article for Stunt News! I would wager the resulting scoop is also stronger than one merely carved from a block. Quite a sensible approach, and professional, too!

Tim

WOW! I don't know how ya'll do all this. I have a hard enough time building profile fusalages.

Really enjoy the pics as always. I think I have learned more from your pictures than anything else. Simplicity is a joy to behold.

Thanks for sharing Al.
Finch

LAST EDITED ON Feb-13-04 AT 06:02 PM (CDT)
 
Finch,

If you'd like to build an easy to build, great flying profile with different looks and which will provide the capability of a good engine run with a stock Fox .35, get the article/plans for Al's Mustunt I. You'll like it.

LAST EDITED ON Feb-12-04 AT 05:46 PM (CDT)
 
I know you just showed us how you did it, but my first thought was "how did he get the aluminum finish"(ref last pic). Its a dead ringer for the real thing......nicly done Capt.

Outstanding, Al.

The last photo is very cool, too. I think I can see where some oil leaked onto the scoop.

Mustangs forever!

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Ideas are like rabbits. You get a couple, learn how to handle them, and pretty soon you have a dozen." -John Steinbeck

Ron B.
F4Fguy

Al:

Re last pic,glad to see you've finally come around to the "as it really is" school.Here are some pics of mine.It's all molded from 1/16" and 1/20" 4-6# balsa.I have no idea what it weighs,I figured it had to be lighter than any another way.

The aircraft is an experiment;a dual purpose,RC/U/C,.15(S.T.) powered,sport scale,P-51D.With everything in it but the radio,but with servos,it weighs 30oz.Thats with full house,engine,retracts,and flaps.I figure a full up weight of 38-40oz.Not too bad for a non stunter.

LAST EDITED ON Feb-17-04 AT 11:28 AM (CDT)
 
Ron,

I was always in the "as it really is" school. I design my airplanes by starting with the size and moments that I want to use with performance in mind, then try to add as many realistic lines and scale features as possible without screwing up the original intent to build a competitive airplane.

By sticking with what I know, or think I know, about aerodynamics, I have progressively been able to design and build increasingly realistic semi-scale airplanes. Part of the evolution began with examining basic concepts about stunt ship design and realizing that many "givens" weren't necessary to good flying characteristics, dihedral, for example. The other innovations which made ever more realistic airplanes possible were building techniques, like molding, which made interesting shapes possible without adding weight, the 4 gram radiator, for example.

The downside is, of course, while my airplanes don't lack for competitive performance, they are bitches to build which discourages duplication. There is a great deal of thought given in my design phase about moments, areas, pitching moments, stability, power loading, props, thrust, lift, drag, wing loading, tail volume coefficients, vertical and horizontal CG locations, structural considerations and the demands of the pattern as we fly it. Any semi-scale airplane which wins the NATs, Walker and places well in the World Championships is a much, much better competition airplane than its appearance would casually suggest. Over the years, I have gotten better than deserved scores by judges who like my airplanes. I have also been killed by judges who have preconceived ideas of what semi-scale airplanes are capable of, and simply refuse to believe what they see. With more good semi-scale airplanes around now, like Gordan's Tony, I believe that judging now is more reliably based on the quality of the maneuvers. Semi-scale is no longer much of a novelty, and it should be so.

Meanwhile, there doesn't appear to be a heck of a lot on interest in Mustang radiators or a simpler technique to build them.

I find the "semi-scale" term rather strange in PA, as in reading many, many back issues of Flying Models, Model Airplane News, Air Trails, etc, this term has been bandied about for ever. It seems that the "trend" is toward semi-scale in many articles from the late 40s' to present, yet many act as if it was a new trend. If not built right, semi-scale planes are duds, but the idea is always, lurking and when someone does a great semi-scale and it is a winner, the magazines act like the local weather man;ie: "God just invented snow and dumped the first samples here last night." How soon we forget. The Stuka Stunt, a hundred Mustangs, Spitfires, Sea Fire, Typhoons, F8Fs, Corsairs, Hurricanes, ME109s (BF109), Focke Wolfe 190, PT13,15,17, PT19, STA, Zlin, F4F, A6M2, AD1, B17, B25, F6F, XF5F, and many more. They look like airplanes, they are airplanes, and we love these airplanes, so we build them, drool on them, want them to be successful, but alas, many are not. So, typically, it's the few really great flyers we remember. The irony is that most of the PA models we do build, if they were real, could not get off the ground because the pilot has absolutely no vision of the runway. Ok, he could get off, but the landings would be dicey at best. At least a scale like model looks real. FWIW. NO repsonse is necessary.

>I find the "semi-scale" term rather strange in PA, as in
>reading many, many back issues of Flying Models, Model
>Airplane News, Air Trails, etc, this term has been bandied
>about for ever. It seems that the "trend" is toward
>semi-scale in many articles from the late 40s' to present,
>yet many act as if it was a new trend. If not built right,
>semi-scale planes are duds, but the idea is always, lurking
>and when someone does a great semi-scale and it is a winner,
>the magazines act like the local weather man;ie: "God just
>invented snow and dumped the first samples here last night."
> How soon we forget. The Stuka Stunt, a hundred Mustangs,
>Spitfires, Sea Fire, Typhoons, F8Fs, Corsairs, Hurricanes,
>ME109s (BF109), Focke Wolfe 190, PT13,15,17, PT19, STA,
>Zlin, F4F, A6M2, AD1, B17, B25, F6F, XF5F, and many more.
>They look like airplanes, they are airplanes, and we love
>these airplanes, so we build them, drool on them, want them
>to be successful, but alas, many are not. So, typically,
>it's the few really great flyers we remember. The irony is
>that most of the PA models we do build, if they were real,
>could not get off the ground because the pilot has
>absolutely no vision of the runway. Ok, he could get off,
>but the landings would be dicey at best. At least a scale
>like model looks real. FWIW. NO repsonse is necessary.:P

Ron B.
F4Fguy

Ty:

A response IS necessary.

If not built right,Non semi scale airplanes are duds.

Of the ones named,some were great airplanes,but precious few were great semi scale airplanes.Theres a vast difference between semi scale and cartoon scale.Most of the so called scale stunters were/are thinly disguised Noblers,Patternmasters,Geos,etc.Some are hard to fly well,and some are great airplanes.

As far as I know,no one is beating anyone else over the head to build scale stunters.Those who do build them do so because they really want an airplane that looks like an airplane.Usually,they also want to explore the "envelope",rather than assume there's only one way to skin the PA cat.

Scale stunters are different,but the well designed ones fly just as well as their nonscale brothers.Any one who builds one of Al's Bearcats or Mustangs TO THE PLANS,will have a very competitive airplane.The same is true of Kieth's FW 190,Don's PT-17,and,I suspect,Paul's B-17 if you're man enough to hold on to it.

My personal criterion is;If it isn't competitive in Both PA and sport scale(not "fun scale"),it's not worth the effort.

Ron B.

Ron, I agree. My point is that "scale" types have been around from the beginning, but very few ever really were great flying models. "Cartoon" scale, yep seen a few o dem too. But when you and AL and a few others come up with a scale or "semi-scale" stunters, they are just fantastic in execution and looks and flying ability. But, too many times editors seem to act like they are "new" to the scene. I wasn't making a point so much as an observation. If one goew back to the 50's in the magazines and read forward, you will see what I mean. By the way, it's not an airplane if it doesn't have a round engine and a tail hook. Fly Navy.

>Meanwhile, there doesn't appear to be a heck of a lot on interest in Mustang radiators
>or a simpler technique to build them.

I read and looked with great interest, as I do with all of your posts. 'just didn't have anything to add.

SK

Ron B.
F4Fguy

Sorry Al,it was a joke,I was refering to the oil stain on the full scale scoop.I guess I wasn't clear.

Mea Culpa,