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Brian Jackson
03-29-2005, 09:36 AM
Greetings, All.

Next week I'm having the foam cores for the QB Tail CNC'ed. I've re-designed it slightly after having spoken with a gentleman here whom taught me about offsetting the fin/rudder to compensate for helical propwash. I'm grateful for that knowledge, and glad I waited before lunging forward with it.

I'm working on a design now for the matching Instrument Pod, which I hope to have the foam cores CNC'ed concurrently with the QB tail, though there's no rush or anything. Attached is an image of the preliminary design. A couple of the shots make it appear much larger than it really is because I zoomed way in on a perspective view. As is, the whole unit is only 11" wide, and is designed around (4) 2" micro-instruments, with the rectangular area under the middle two gauges for a digital Rotor Tach.

The front panel is slightly concave, radiused about the pilot's head while the "shell" encompasses the depth of the instruments, leaving the forward "tip" to house and internally mount the pitot tube. The recessed "ridges" in the shell add a bit of strength, though for something this small probably aren't necessary.

With the horizontal arrangement of the instruments, I wanted to keep its plate area as small and aerodynamically neutral as possible to keep it from acting as a "canard." Also, I haven't yet determined its exact placement or mounting method on the keel.
Anyway, in seeking guidance, I'm submitting this to the Forum for criticizm, critique and suggestions from those in the know. I love the idea of fabricating my own instrument pod, but if there's something I'm overlooking or am ignorant of, I'd like other's input before I invest any more time and resources.

Thanks in advance for any feedback.

Regards,
Brian Jackson

banaari
03-29-2005, 11:10 AM
Nice one. VERY nice one! :)

Only thing that does spring to mind - are you sure you want to go with the 2-inch airspeed and altimiter? IMHO the 3-inch stuff is easier to monitor (more than twice the dial area), and your panel design should quite gracefully accept the extra height in the middle. Just a thought.


cheers,
John

PW_Plack
03-29-2005, 01:07 PM
Brian,

Ditto on the 3-inch altimeter and airspeed. The small ones are a squint-fest in real-world use.

Also, if the ridges might have any aerodynamic effect, consider making the pod smooth, and getting the esthetic effect of the recesses with a paint effect.

Brian Jackson
03-29-2005, 01:54 PM
Thanks, guys. That's exactly the kind of stuff I need to know. If 3.5" (standard) AS & ALT gauges are used, it widens the pod quite a bit, creating more plate area. But I agree those critical instruments shouldn't be a "squint fest" as Paul so eloquently described. :D

Thanks for the insights. I'll rework this.

Lastly, the recesses are there to create S-curves on the composite surface at vulnerable areas. That's why the center spine gets wider as the shell gets wider. Truthfully though, it does look kinda cool. Sorta reminds me of the nose-pods of the shuttles in that old show "Space 1999" from the '70's. Anyone remember that one? (Man, I'm showing my age here!)

KDOG
03-29-2005, 02:18 PM
Jeebus, Brian! Will you stop trying to outdo all of us and just get a Starbee instrument pod like everyone else?!?!? ;)

Brian Jackson
03-29-2005, 03:14 PM
Sorry, Kevin. Just playing with shapes.