Return of the Wooden Mock-up

I did this once before. I took some measurements to make a wider airplane than the plans call for. The measurements were approximate because at the time I thought that I would make the airplane taller as well, in order to acommodate the protrusion of my head above the seat back bulkhead, "C." I also had not made an attempt to accurately form bulkhead "D", the bulkhead that is midway down the fuselage behind the cockpit. I knew "D" would not fit when built according to the plans but I wanted to wait until I was comfortable with the height of "C."

This month I refined my wooden mock-up and incorporated some smaller changes, to the spars, and the height of bulkhead "B", the instrument panel. I now have better measurements. There is also a discrepancy in the length of the top of the rear fuselage. The plans mention 72 inches but I am coming up with 70. The flat bottom of the fuselage is 72 inches, from the trailing edge of the wing to the end of the tail. The difference between the 70 and 72 is due to the set back angle of bulkhead "C", at 20 degrees aft of vertical according to the plans. The plans don't provide a side view so I am assuming that all bulkheads are parallel. At least, that is the way I am building the fuselage!

I have made numerous drawings to try different sizes. If bulkhead "E" is built according to plans then "D" won't fit. If "D" is built according to plans then "E" must be much taller and wider. So "D" is now fixed and I am getting the dimensions set for two more bulkheads as well.

Botched Firewall

I couldn't make the firewall work the way I wanted it to. I didn't want to change the firewall or the two rear bulkheads but that is going to happen now. As I sat in my cardboard airplane, winging over the Sierra Estrellas, I realized my feet were binding on the rudder bar. The lower side rail was pushing my feet together and squishing them up against the fuel feed line.

And if that wasn't bad enough my toes kept pushing against the cut out I had to make to accomodate the rear mounted mag. The thermals were gettting a little uncomfortable and my rudder work was making me wish for a bigger firewall.

I sat back, reached outside and picked my beer gingerly off the wing root. Cardboard airplanes make a lot of sense. I need to stretch that firewall 2 inches wider to conform with the 2 inch stretch at the cabin seatback. This will make my size 12 boats a little less claustrophobic and less likely to put me into an unwanted rudder throw.

I sure wish I hadn't cut the plywood form blocks for the plans-sized firewall though! I was premature on that but I can use the wood for something else, nothing goes to waste here. The good news is that the side rails won't have to bend as much because the firewall will be scaled up appropriately.

The Cardboard Instruments: Redux

Crap.
The 1 1/2 inch instruments are made by VDO. I like them a lot and they would fit VERY nicely on the panel but... they are auto instruments. No, that's not the problem, the VW engine is a converted auto engine. The problem is that they just aren't a standard.

The standard, or a particular standard, is 2 1/16 inch instruments. They are made by lots of companies. This is an issue because if the 1 1/2 inch instrument(s) fail, it could be hard to find replacements. So I am moving up to bigger 2 1/16 inch instruments. More weight, more biggah.

This means making a bigger panel, or more likely, putting two instruments on the side pillars of the panel. That is a tight spot anyway as the mixture, throttle, and carb heat will be on or near the left pillar. The hourmeter will be on the right, grouped with the master switch and panel power and lights.

Ha ha ha, oh man, where does the copilot sit?

Of course the option is to go MFD. One expensive screen in the middle of the panel. It would have all the bells and whistles AND be solid state. Yes, and when it dies so do all of my electronic senses too.

Did I mention a transponder and radio? No? How about GPS? Okay, I'll take that two foot wing extension and a turbocharger to go. And a diet Coke, because somebody needs to lose weight.

The Cardboard Instruments

My panel is crowded. It is really stuffed and I know my airplane is going to be heavy so either I just live with this knowledge or go for a 2 foot wing stretch. But that is another post's topic.

The panel I want must be sufficient for night VFR. I know this can be an issue because this is a very small airplane powered by a VW engine, typically lit by only one magneto. Losing an engine at night would be, well, challenging. I love simple airplanes, I really do. I drool when I see a Tiger Moth or a Weedhopper. The thing is, I want to fly at night!

I am not talking about 3 hour trips over the desert or up into the mountains. I am thinking more along the lines of a full moon flight, or an escape from the heat ride that may last an hour or so. That means lighting, and it means having a gyro. I don't why I keep thinking gyro other than those rare occasions when the horizon disappears. It is a psychic crutch, I know, I don't have an instrument rating and I didn't use the artificial horizon when I flew, at least not often. There was never much of a reason to because it's more important to be able to "see and avoid."

But I felt better knowing that it was there. So it's running around my head and I know it is no trivial task to put one in this plane. They are heavy, long instruments and there is no room in a Teenie's panel to speak of. Nevertheless, I made some cut out cardboard instruments in three sizes:

1 @ 3 1/8 inches : the artificial horizon
4 @ 2 1/4 inches: airspeed, altimeter, vertical speed, and compass (directional gyro?)
5 @ 1 1/2 inches: cylinder head temp, oil temp, oil pressure, voltmeter, hourmeter
1 @ 2 to 3 inches: ball slip/skid indicator

A big, fat panel! Here is the radio call:

"Phoenix Approach, Experimental 6 Tango Tango, Heavy, twenty south at 2000 inbound to land..."

And then:

"Speedbird 555, you're number two for landing runway 26, caution wake turbulence, Teenie Two on short final."

Or something like that. Heavy, really heavy.

The Cardboard Cockpit

The first version of the cockpit is er, complete. That is, the box that my brother's bass drum was shipped in just happens to be 23 inches square! Across the seat back it is 23 inches and that gently tapers to 22 inches at the instrument panel. The first thing I noticed is that I would like the instrument panel to be about 1/2 - 1 inch higher in the center to accomodate more instruments or at least slightly more options in selection.

I sat in the box, er, cockpit (yes there are pictures) and I realized I made the sides too high. The cockpit side rails are 18 inches from the rear wing spar up to my shoulders, at least according to the plans. I will cut them back tomorrow because they are nearly 22 inches high right now and I think the view would be spectacular with shorter side rails (shorter in height not length).

Thanks to the Pearl drum company for my Teenie Two mock up. You guys are GREAT!

The Cardboard Airplane

I am building a cardboard airplane. I wonder if this is the way the Wright Brothers started out? As I may have mentioned, a Teenie Two built exactly to plans is a little too snug for me. It's not necessarily a bad thing because I suspect being strapped into that tight cockpit gives one a sense of being truly part of the airplane. I am thinking that I will like flying the airplane a little too much and a larger cockpit will allow me to enjoy longer flights in it.

So rather than jump into cutting metal, I decided I would build a mock-up of the airplane to see where the dimensions might be enlarged. The seat back, the widest point of the Teenie's fuselage is 21 inches when built to plans. I am stretching that to 23 inches. The instrument panel a.k.a. bulkhead B, will be 22 inches wide with a height yet to be determined.

I also need to determine the width of the firewall, bulkhead A, and the two rear bulkheads, C and D. It is my intention to leave them as they are in the plans to avoid more changes if I can.