Meet Helen (Hellie) Copter.
Retired M*A*S*H medical helicopter.

She is crocheted with a 4.25 mm hook and Lamb's Pride Bulky. I made it all up as I went along, so there are probably ample mistakes and things that could be improved upon.
Here's a better profile shot. The main parts of her tail are knit icord, and the cross pieces are single crochet. I wove wire into her propeller and the end of her tail (I should have used the wire as I went but I bought it after felting didn't produce the desired stiffness).

Her eyes and medical crosses are needle felted on.

Any and all comments, questions, criticisms, and sarcastic remarks are most welcome.
**Update**
Here's the pattern of sorts (some parts are totally improvised and I couldn't sort it our this morning)
Hellie Pattern
Supplies:
Lamb’s Pride Bulky (or other bulky wool)
4.25mm crochet hook
4.00 mm double point knitting needles
craft wire
some roving and a felting needle or other means of adding eyes and other features
crochet stitch marker
Main Body
Worked in a spiral
Start with a magic loop
6 sc stitches into the loop, place marker at beginning of round
1st round: 2 sc in each st
2nd round: sc in first st, 2 sc in next stitch, continue like this around
3rd round: sc in first 2 sts, 2 sc in next stitch, continue like this around
4th round: sc in first 3 sts, 2 sc in next stitch, continue like this around
5th round: sc in first 4 sts, 2 sc in next stitch, continue like this around
6th round: sc in first 5 sts, 2 sc in next stitch, continue like this around
Next 5 rounds work even
12th round: sc in first 5 sts, dec in next st (2 sts become 1), continue like this around
13th round: sc in first 4 sts, dec in next st (2 sts become 1), continue like this around
14th round: sc in first 3 sts, dec in next st (2 sts become 1), continue like this around
Continue like this until you have 3 sts left.
Work even for 2 rounds.
Propellers are worked from these 3 sts. (I don’t remember exactly how I worked this part, but this is mostly correct)
From each stitch work a chain of sc sts (ch 1 sc in st, ch 1 sc in st) for about 14 sts (I hope this makes sense)
When I was finished, I wove wire through the propellers but it might work better to work it through as you crochet.
Landing skids (make 4) (these are a little longer than the propellers)
Ch 3
Skip 1st ch and sc in each remaining ch st
Ch 1 sc in each st
Continue like this until they are desired length (these fulled pretty well so I can’t really count rows)
When desired length has been reached dc to 1 sc in final row, break yarn.
My landing skids do not have wire in them, but it would probably be a good idea to include some. So if desired sandwich some wire inside the 2 layers before crocheted them together.
Each landing skid is 2 layers, sc around the outside to attach the two layers.
Landing skids are attached to the body by a short length of scs the width of the skid (2 sts) and about 3 rows tall. Start the sts right in the landing skid, and once you reach desired length break yarn and sew to the main body.
Tail (knit and crocheted)
The main parts of the tail are knit I-cord
Make 2
Using the dp needles cast on 3 sts.
Work in I-cord until it reaches a length of about 9-10 in (or twice the desired length of the tail).
Once 2 are made attach ends to the main body. Each tailpiece should be attached about an in apart on the back of the body and the distance between the top and bottom is about ¾ in.
Now the tricky improvised part. For the cross pieces in the tail I used sc sts to create the angled crosspieces. I just improvised it and don’t think I can really decipher what I did in a coherent fashion.
Tail rotor
Make 1 (or 2 if you want it to be double sided (but that might make it too thick))
I added wire at the end, if you are so talented you might want to work the wire in as you go.
Ch 11 (or so)
Sk 1st ch and sc in the rest of the sts
Do 2 rows
Break yarn
Sew on end of tail
Finishing
I tried to full my helicopter, but it didn’t work super well, so she is half fulled (lots of time trying to hand felt and a trip to the Laundromat). Since she didn’t stiffen up much, I added craft wire to the propeller and tail as that was all I could manage to weave the wire through. I say add it to wherever you want your helicopter to be stiff (or posable).
I needle felted nice big eyes and hospital crosses but any sort or adornment would work.
I think that’s everything, but if I’ve missed anything, or it’s too confusing just let me know.