Hi AVI;

I haven’t considered the Mk XVIII. I think I’m OK with the XIV, as it has a pretty massive V-Stab already.

Weight will indeed be greater with the detachable wings, but no choice here. My garage won’t house a full wing. Plus, I just want them detachable. All kinds of potential reasons why this flexibility might be needed.

The balance issue is a concern, of course. I still don’t fully understand how the 2 place Spit trainers do it, I mean with the solo flight from the front. I know there’s 130 pounds of steel in the nose, but it must just simply be a case where the CG travel is within limits whether it’s solo or dual, low fuel or full tanks. I can see how the effect of adding in a pax would be less significant on a bigger, heavier plane, but still I scratch my little head.

I work at the National Research Council’s Institute for Aerospace Research. Don’t worry folks, I don’t design critical structures! I design and machine tools, jigs, test fixtures, stuff like that, but my main bag is to be part of the composite team. Carbon fibre, fiber glass, etc. You’d think I’d be all over composite materials.

First, a lot of what I lay up, bag and bake is done in an autoclave. Pretty tough to do that on full sized spars. Even though there are out-of-autoclave materials and methods, I don’t want to go with carbon fibre or fiberglass. As you have previously pointed out with all-metal construction, you’d be building the aircraft twice, at least. You have to apply the plies of CF to a mold of some kind, vacuum bag it and bake it under resonable control. A whole new ball game, and the molds would all have to be made.

I enjoy working in the composite department, but I’m not fully sold on it’s use in aircraft, even before the very public outcry of the Boeing employee who was canned for his views on the 787. I admit that my Spitfire replica wouldn’t see the temperature extremes that a jet liner would, but I still have reservations about CF. Ever get a sliver of carbon fibre in your finger? They’re “special” and not in a good way. Can you imagine getting a sheaf of those up the kazoo in an other wise survivable belly landing?

The likely approach will be purchasing a set of plans from Terry Wilshire for an 80% Spit, doing some mods to make it a Mk XIV not a MK I, add a method for wing removal, and proceed. These are all doable things. Just do I have the time, budget and drive? Time will tell.

Cheers, Tom.

Hi Dazdaman, Mk I and Mackerel;

First, thanks for the replies. I can see that you guys have indeed thought about the whole wing detach issue.

So in order;

Dazdaman, you;ve asked a fundamental question, “Why do I need to detach the wings at all?”

I have this nagging feeling that hangering the aircraft may, at times, be more challenging than I’d like it to be. I haven’t checked into this, although I should. If I run into problems, I’d like to have the option of storing this beast at home in the garage. Not to mention the fact that that’s where I’d build most of it. My garage is probably long enough to do the fuselage, but it won’t hold the wings done in one long piece. My plan is to create a jig and do the wings side by side, parallel progress style.

I am sure that I would be saving complication, but the reasons are strong enough for me to at least seek out the possibility of removing the wings.

Mk I:

I hate that when I type up something perfect and it disappears! Happens often enough.
I agree with you that taking off the wings would not be a snappy little task. It would take time, for sure. This is not meant to be typical, just doable in an “emergency” situation.

I really do have to check into hanger availability, but it’s so long before that’s even an issue (if ever).

Mackerel:

Building a real Spit would be killer expensive. Merlin engine, actual metal parts
built to exact scale. Not possible for me.
The balance issue is certainly a concern, and other than ballast in the nose, I don’t fully see why the two-place Spit can be soloed from the front. Unless, of course, the extra person just doesn’t make the CG travel that much rearward.

Well, thanks boys. If I lived on a hobby farm with 1000+ feet of flat land, I’d not worry about the wings being one long piece.

Cheers, Tom.

Hi Stuart;

Good question, and I do have reasons why I want the wings detachable at the root. Mostly smallest possible storage “footprint.” It also, has to do with building it, and garage space available.

Richard, I haven’t made firm choices about wood types yet, but here’s what I’m thinking, subject to change:

fuse frames 1/2 or 3/4 plywood, (Finnish Birch?)
Spar caps and fuse longerons, laminated Sitka spruce
spar shear web plywood, thickness, number of plies, not yet known
skins for wing and fuse 2 and 3 mm plywood type??

I will draw on experience of others, if I choose to proceed with the project. I like a lot of the features that I see in Terry Wilshire and Bob Cutting’s Tally Ho project, for example. I might look into Jurca’s 75% wood spit to see what it’s like.

Thanks, Tom.

Hello Boys;

Ross, that’s one fascinating program you mentioned. I did the demo version, and it’s neat to first understand the NACA number system, then see how changes affect the foil shape. See, I told you you’re a tower of knowledge.

Question, what if the max camberline height is at 35% and not 30 or 40%, (a nice round number) ?

2213 at the root means the max camber location is at 20%. What would the number be if it were at 25% ? Or does the NACA system force the designer to stay within rigid increments? That would seem odd and undesigner-like.

You can see how little I know about the above, but I’ll dive into the demo and learn all I can.

Thanks again. Never saw that program before.

Additionally, I’m well under way with my fuselage wood mockup. My kids were climbing through it last night. The goal is to safely wedge 2 people into a Spit fuse that’s a 75% replica. Shrink an already tight aircraft, and add a second body. Piece of cake, but a ton of fun to work on. Will share pictures shortly, success or failure.

Cheers, Tom.

Hi Mk1;

Thanks for all the detail. Every bit helps me gain an understanding of the wing or other structure.

The stall seems very low on your aircraft, and I’ll bet that helps a lot on landing and roll out.

How much detail about the wing is there in the MkV manual? Rib detail, or just a general photo or two?

Tom.

Hey D;

Thanks for digging. Sometimes when you get to the details, it’s not quite what you thought. But appreciated anyway.

Tom.

Why Not Make the Replica Spit a Two Seater?

Hello;

Bless me father, for it’s been a while since my last post…

One thing that has been bothering me about the whole concept of building a Spitfire replica, is that it’s a very solitary project. It’s a single place aircraft, and despite the expense and years of work, can ultimately be enjoyed by only one person.

I recall that one of the things I enjoyed most about flying years ago, is having someone with me. I didn’t happen often, other than instructors, but I did like the idea of sharing the experience. So a Mk IX Spit seems wrong, purely from that perspective.

I have been studying the Mustang a bit lately, and at first that seemed like a good alternative. Merlin powered, beautiful lines and certainly a significant place in history. Probably easier to make with its straighter skins, and easier to ground handle with its wider track. There seems to room for the second person in the Stewart and other Mustang replicas, although the Stewart is no longer in production, including the plans from what I have heard. However…

The Spitfire is not an easy aircraft to leave. So I have considered making the Spit a two seater, sort of like the Aussie Mk26, but definitely not like the trainer. I find the trainer two-seater to be unattractive at best. That bulbous extra canopy really detracts from the looks, in my opinion, no offense intended to Mrs. Grace and others who own them. So is there a way of making a two-seater, possibly even a dual control Spit and maintaining the general look ?

First, I’d have to give up the MkIX highback look. I prefer the highback, but I could live with a lowback, like the P-51D, with it’s teardrop canopy. So it would effectively be MkIX or MkXVI lowback.

If you’re so inclined, please have a look at the 2 pics below. The first is unaltered, and the second has the canopy stretched. It has to move forward 5 or 6 inches, and back about the same amount, maybe more. Does it look odd? Does it look terribly oversized? Not as odd as the trainer two-seater. And with a 70 % replica, the pilot’s head would be pretty close to the proportion shown in picture 2. Could we squeeze a second person behind the pilot? I’ll have to do some sketching and find out. Frame 11 would have to change at the top, so the rear seater could climb over it, but we shouldn’t need armour plating today.

Wadda ya think? After all the expense of building a Spit replica, it would be nice to share the flying experience. Observations, ideas? Is the concept feasible?
Cheers, Tom.