Tuesday, May 17, 2011

Useful Little Twin

I'm not getting back into the meat of aviation as quickly as I had intended, so I'm going to just pick up a manual and start reviewing systems. Eeeny-meeny-miney-moe gets me an airplane type I have flown a few times. I knew three people who owned these airplanes, and have flown four different aircraft of this type, including a couple of flight tests. It's a great little twin, a good IFR platform and the extra engine will actually take you somewhere, even with the aircraft well-loaded. There's no reason for me to obscure the make and model, except that it's fun and I know some of you will enjoy guessing.

Now I'm trying to decide which system is the most generic, so you don't all know it immediately. The trick is that even as I look at the index of the manual (it's a photocopy of my friend's POH) I smile remembering unique quirks of each system, and how they all interacted for good and for bad. I guess I'll start with the airframe.

It's an all-metal low-wing aluminum-skinned monoplane with semi-monocoque construction. (The semi-monocoque bit means that it has internal bracing but unlike early open-frame or canvas-covered aircraft, the skin is necessary to the structural integrity of the airplane). The fuselage is built in four pieces: nose cone, cabin, tail cone and an enamelled steel tube structure that runs from the tail cone to the nosewheel to hold it all together. The wings are rectangular, with a main centre spar plus a fore and aft spar, plus additional lateral stringers running through the ribs. The main spars are bolted together in the centre of the fuselage, but the rest of the wing does not carry through, but is bolted to the steel tube structure. The wings have a removable tip section, and five degrees of dihedral (the angle at which the wing slopes up from root to tip). The ratio of nose-to-tail length to wingspan is 0.81. That last is not a standard aircraft statistic, but I spoil guessing fun if I actually give the length and wingspan.

A detail in the manual is that the main wing spar is "stepped-down." I'm not certain how that is achieved. I assume that it's thicker at the wing roots than the wingtips through having less metal, but rather than being tapered ('cause they'd presumably just say "tapered") the gauge is otherwise quantized. I'll try to find out exactly how that works on a metal wing spar. On a wooden one it might be a reduction in the number of laminate layers. I don't often see aircraft wings with the skin removed, and when I do it's usually either an ancient hulk or a hobby plane under construction.

9 comments:

elvis said...

Cessna 425 Conquest?

Anoynmous said...

My first guess is PA-31.

From the Flight Deck said...

Aviatrix. I want to apologize for not visiting your blog more frequently.

Looks like you ran into some turbulence with a “commenter.” Actually, another blogger and follower told me about things…they too have their radar on.

No one likes heavy turbulence and that includes pilots.

I remember you giving me words of wisdom about not responding to every comment on my bog. I didn’t listen. I tried, but I couldn’t resist. But the odd one sets us back…wondering…why do we post words in the eternal void of the Internet? It’s time consuming, imposes stress on the family and for what?

It’s a given we pilots are passionate and some of us want to connect that passion with words. But can we lay down our pen?

As of late, I’m wondering if I should pull the plug and move on. Believe it or not, you are my blogging idle. Yes, you! Sure other bloggers think they have the gift to write, but you were an aviation blog pioneer…you blogged passionately for a very long time and frequently.

I could say, "don’t take those cutting remarks to heart," but I know I would.

What I am trying to say is…if you go…I go….

(We are probably the two biggest solo bloggers in Canada) or do I have my head in the sand. ☺

I only wish I could get your resume pulled at Air Canada. The present system is embarrassing to us pilots.

“Blue side up!”

Captain Doug Morris

Frank Van Haste said...

Dear Trix:

+1 to what Cap'n Doug said. I've not commented during recent weeks but be assured that I am reading and hoping for good things to come your way Real Soon Now.

Maintain a level attitude...

Frank

DataPilot said...

Believe it or not, you are my blogging idle. Yes, you!

I see that I'm not the only person who has great respect for your blogging talents. You are the only blogger that I know of who posts something worth reading every day. And I love suspense of wondering, "What's Aviatrix going to write about next?"

By the way, I think I may know what the "Useful Little Twin" is. If I'm correct, it's one of my favorite planes.

From the Flight Deck said...

Corrigendum from Captain Doug

Looks like I said "bog" instead of "blog."

And "idle" instead of "idol."

Now I know what "commenters" go through....:))))

Frank Van Haste said...

Cap'n Doug:

Darned keyboard can't spell, eh?

(It's all good -- we heard (and endorsed) what you meant. :-) )

FVH

Anonymous said...

Yep - fingers crossed for great news really soon on the flying front. Your recent post about getting a "normal" job concerned me - I've got a "normal" job, which fortunately has allowed me to get as far as my PPL. I never, ever think "I wish I was back in the office" while I'm flying - certainly can't say the same the other way :-)

Anonymous said...

A.
Thanks for your blog. I seem to remember reading somewhere that the Spitfire spars were made of sections of different lengths, slid together to form a stepped construction, thickest at the roots.
Regards
Bruce