Bagalini Colombo - article with great pics

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cluttonfred

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I stumbled across this article (with beautiful photos) on the Bagalini Colombo, a wood and fabric two-seat parasol monoplane (think Fisher Flying FP-505 Skeeter meets Evans VP-2 Volksplane). This amazing little plane weighs just 150 kg empty with a Rotax 503. With a gross weight of 318 kg, it carries substantially more than its own weight. Performance is, of course, quite modest, but it's hard to beat the economics of something like this for local flying just for fun.

colombo.jpg

Bagalini Colombo - Storia di un classico | Volare VFRMagazine (in Italian)

Google Translate (in English via Google Translate)

Here, too, is a video clip of another Colombo, this one with a VW engine.

[video=youtube_share;R0s1sHypaZY]http://youtu.be/R0s1sHypaZY[/video]

Cheers,

Matthew
 

cluttonfred

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And for the reason I came to this old thread....

Here is another lovely Bagalini Colombo (also VW-powered it would appear). Builder Michele Visciglio just won the
Club Aviazione Popolare (CAP) Premio Caproni at the Aeroporto di Foligno. Small and simple and affordable can still be beautiful and win prizes.

colombo 1.jpg
colombo 2.jpg colombo 3.jpg

Clips of this same Colombo in flight can be found here: https://www.youtube.com/user/zartan8822/search?query=Colombo

PS--It would be good fun to develop a safe and simple "Super Colombo" more suited to big and tall pilots and heavier engines since the Colombo as designed has empty/gross weights of 150/318 kg or 330/700 lb with a 42 hp Rotax 447 so just 370 lb useful load. In my case at least, with 10 gallons of fuel that only leaves 100 lb for a passenger. :-/ A version at the maximum basic European microlight gross weight, say empty/gross weights of 225/450 kg or 496/992 lb and the same wing loading with a basic VW conversion would have slightly better power loading than the original Colombo. Keep in mind, though, that the Colombo was designed for essentially Part 103 ultralight performance, so it's a fair weather, around the patch fun flier, not a cross country machine. Running some quick numbers at that 450 kg/992 lb gross weight with a 60 hp VW conversion and tweaking the aspect ratio and stall speed to get a little more performance, I get a 36' span and 5' 6" chord for 198 sq feet of wing area. That would give a stall speed of 35 mph, a maximum level speed in the 90s and a cruising speed in the 80s so quite a bit better than the Colombo but still nice and slow.
 
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cluttonfred

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I would call it more if a mixed material Jr Ace.

Little more than half a Junior Ace in terms of weight! ;-). It’s all wood and fabric except for the struts and gear and the fuselage is basically an ultralight version of a Volksplane but instead of a rear fairing the tips of all the bulkheads are rounded at the corners to form a flat-topped turtledeck of sorts.

AC865697-7867-4932-95F0-591E032116E6.jpeg 1663095541975.gif

And here’s another pic of Michele’s award-winner.

1663096333414.jpeg
 
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TFF

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A Double Eagle is 385 lb, it’s closer. The weight isn’t the biggest deal. The Colombo is a light duty plane to the Jr Ace. Might be light duty to the DE. A Jr Ace is going to be able to handle any reasonable VFR day. That might be an important point. If weather where one lives is really cherry, it would be ok, although it’s still a little skimpy for me to feel comfortable giving a ride. It’s closer to can do not should do. It would be interesting to review the plans and compare to others.
 

cluttonfred

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The plans are very complete and professional with careful attention to minimizing weight. Quoted load factors are +6.7/-3.5 G so perfectly reasonable for a fun flyer. Keep in mind that the Colombo really is an ultralight in mission with a wing loading of just 10.5 kg/m2 or 6.2 lb/sq ft.

PS—How about a stock Colombo with a Verner 3V in Italian WWI colors? ;-)

1663148397051.png
 
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TFF

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I think those load factors are ultimate not useful flight loads. Not that it’s weak weak but divided by a reasonable factor, the numbers make more sense.
 

cluttonfred

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Assuming that those are ultimate loads at 50% higher than permissible loads, that's still +4.47/-2.33 which is consistent with utility category (so stronger than normal category) certified aircraft.

I think those load factors are ultimate not useful flight loads. Not that it’s weak weak but divided by a reasonable factor, the numbers make more sense.
 

TFF

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Right. With the statement of how many times really; in real practice. A lot of these planes hope for the best. Best piloting, best building, best materials. I’m just a doubting Thomas when it comes to very minimalist aircraft. They can be fascinating, but I think they should be taken with a healthy dose of skepticism; a lot more than people give them.
 

Victor Bravo

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Even fully certified aircraft are certified to withstand XYZ loads once, or a few times, without permanent deformation or failure.

There is nothing in the CAR or FAR that I'm aware of that ever said they wanted the airplane to withstand the test loads dozens of times, over and over, for 50 or 70 years, with the airplane continuing to live indefinitely... 'good as new!'.

I believe the trained engineers here will agree that most metals have properties that can change over long periiods of time or thousands/millios of load cycles. Wood degrades over time. Rivets start working. Bolt holes in fittings "oval out".

Flexing the structure of any airplane back and forth, a couple of thousandths of an inch, millions of times, simply has to change something about the structure.

Almost all "normal" airplanes deserve to be treated a little or a lot more kindly as they age. For specialized super light weight, light duty structures like the one in this thread, common sense tells us that this principle is even more important.
 

PiperCruisin

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Even fully certified aircraft are certified to withstand XYZ loads once, or a few times, without permanent deformation or failure.

There is nothing in the CAR or FAR that I'm aware of that ever said they wanted the airplane to withstand the test loads dozens of times, over and over, for 50 or 70 years, with the airplane continuing to live indefinitely... 'good as new!'.

I believe the trained engineers here will agree that most metals have properties that can change over long periiods of time or thousands/millios of load cycles. Wood degrades over time. Rivets start working. Bolt holes in fittings "oval out".
I'm not sure how to understand "trained engineers", but I'll take a shot at this.

Generally, I would not consider the properties to change over time unless you consider corrosion (surface, interlaminar, intergranular) and crack propagation if it is well cared for. Reminds me of wood carvings at the Cathedral of Amiens where the wood was soaked in water for 75 years before processing. Still there and looking great after 750 years.

Fatigue is usually poorly considered. It is subject to stress concentrations and the probability of critical defects and defect size in the area being stressed.

Ultimate loads usually means you can have some damage, but still carry the load. Limit means you have not permanent deformation. I would not consider limit loads to be endurance limits, meaning if you go to limit loads all the time, you'll limit the life of your part. So endurance loads would be what you can endure without significant crack propagation.

The endurance limit is tough to estimate, especially when you consider corrosion and the stress concentrations at joints and materials like aluminum that don't have an obvious knee in the SN curve (generally assumed at 5e8 cycles for aluminum). Think of a bolted joint, you have the stress concentrator of the hole and the fact that it tends to be significantly higher at one edge than the other where the distance makes it stiffer.

So, yeah, take care of them. They won't last forever. Woe to the engineer making predictions.
 

cluttonfred

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The designer has passed away and there is no official source that I am aware of but digital copies are available if you ask around the Italian homebuilt aircraft community. The plans and builder’s notes are, of course, all in Italian. Here is an excerpt from one of the plans sheets:

9628D5DB-4D39-41FD-B090-B0E35170CD9B.jpeg
 
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