Q: Help needed for material choice: scratching rotary 20B

Hi folks! I'm planning to build an RX-7 FC3 with 3-rotor engine the 20b. I've seen TIU's Veilside Fortune RX-7, but I need help on choosing how thick material I should use to manufacture the 3-rotor engine. I know I need to get some Evergreen sheet, but what would be the best thickness for the sheet (please use metric measurements, I don't understand inches). I think Jimmy knows best, which thickness to use, not that I won't appreciate everyones insight and knowledge. Here's a photo of the engine:

http://i25.photobucket.com/albums/c76/Uninen/Yellow20B.gif

Thanx in advance!

I bet the petroleum industry loves that monster! Seriously, just get the assortment packs: 9002 and 9008. Most hobby shops stock them. There will be enough to build up any thickness. In direct answer to your question the housings should be 3mm, the irons 2.8mm in 1/24th. Thats based on measurements from my 13B in the garage.

You could always order one?

http://www.thepartsbox.com/

Or buy 2 Tamiya RX7 kits & cut one of the Rotor Housings off the engine & glue to the other...

Those were the measurements I got when I fabb upthe 20B's little brother...my Cosmo 13B-RE just as CrateCruncher said. I used a combination of 1mm and 0.5mm styrene sheet to make my components. Just remember that the first intermediate housing is thicker than the second one...to me...a little less than double thickness.


http://img92.imageshack.us/img92/5672/dscf0011wn8.jpg
http://img157.imageshack.us/img157/1324/dscf0055um4.jpg

Good Luck!

Jimmy

Thnx folks for your input! @Drift FC: I checked the parts box's offering, and they don't carry the 20B engine. I don't want to waste 33 AUD on two engine kits, when the other is going to be scrapped. Plus when I make one myself any flaws it has are on me, not someone else's. From that I can say to da_ashman that will be also waste of money too, I won't buy two Tamiya kits just so I could kit bash them! One sheet package cost around 7$ (5-6€), and by careful usage You'll make ca. 5-6 engine kit + something more useful parts: so one engine kit cost approx 1$ when two kits around 30$ and both will be useless/worthless after bashing them.

@Crewdawg: thanks Jimmy, You really pulled through for me! That was just what I was looking for!

@Cratecruncher: thank You, I didn't know that I could buy sheet assortments! Thats news to me. Are those numbers Evergreens product codes?

@Cratecruncher: thank You, I didn't know that I could buy sheet assortments! Thats news to me. Are those numbers Evergreens product codes?

Yes. 9008 has 3 sheets: .25mm, .5mm, 1mm. Each is 150x300mm. 9002 has more sheets but I'm not sure whats in it exactly. 217 is a rod and tube assortment pack that may prove useful.