CG postage stamp mounts.

dckrsn wrote:

Cribbs74 wrote:Guys,
Seems he wants me to pay what he has them listed on Ebay for.  He claims that is what they sell for. I think that is a load of bologne and I don't wish to do business with him to be brutally honest.
He only has three listed on Ebay at the moment... None have sold.
He is asking $5 a piece for them his Ebay handle is:  phpfeil

I can't blame you, Ron.
Screw him. Let him sit on them forever.
Thanks for thinking of us though.
Bob

Roddie still has mounts.. (2-piece alum. plate design).. although Eric (getback) reported a stress-failure on a bend in one of his mounts that I sent him last year. I mailed-out a few sets to CEF members.. but Eric is the only one to report testing. The failure could have been caused by the way I bent the angles in the brackets.. or the angle/speed at which the engine struck the ground.. (The FAA report was vague..) Postage to AU would be cheap.. if I don't bend the two opposing 90 degree angles required.. (they could mail flat in an envelope) You interested Rod? Anyone?

KariFS wrote:Thanks for the kind offer Roddie, I only have two postage stamp engines and a bunch of tanked and horseshoe engines so, like Rod, I am pretty much set for a while too. Maybe, if they have the fine thread needles, and I want to play with pressure feed, I'll actually use them.

I do reserve the right to steal your design when I see fit

Actually the CG mount looks pretty flimsy, not worth 5 dollars to me.

If/when I get a "Roddie-style" mount done, I'll report for sure.

Kari, somewhere here.. (possibly in my mount thread).. there's a discussion on bending metal plate. I bent the mounts/brackets (.060" 1060 Aluminum) cold; in a slotted fixture clamped in a vise using a plastic-headed hammer and a small square aluminum block to square-off the 90 degree bends. This technique could have formed stress-fractures along the bend-line. The jaws in the fixture had sharp corners.





Perhaps rounding the jaws could have formed a less-sharp stress-corner to the joint. I may try that. This design does require a lengthened firewall.



My 1/2A Voo Doo (Phred's Phault) will use it horizontally on a 1/4" plywood firewall inset into its foam-wing. Mine is a narrower mount system; compared to a Bee engines'.. but comparable in length. Not so difficult to modify a traditional "Bee-mounting" on a profile-design; to use thinner/taller cheek-blocks.. and a more vertically-rectangular firewall. The firewall-mount pattern width (vertically) is actually the same as the 17/32" crankcase mount dimension.. and would fair-in much sleeker on a profile model, than a tanked-engine would.

These back-plates should not languish-away in a spare-parts bin. They were made in the beginning.. when Cox was making their mark on the hobby. Any reedy deserves to sport one!

getback wrote:Roddie if you decide to smooth those edges for a better bend , I am willing to put it to the test for you I have quite a few PS engines , up to you brother.  

I'm getting ready to mail some stuff out to a few members. I'll send you some more mounts Eric. I've been meaning to do that since last winter..  When I was originally bending the mounts.. I was starting the bend by hand cold.. using my fingers to push the first 45 degrees of the 90.. followed by hammer-tapping; using an aluminum block to finish.

These first (prototype) mounts were bent in a slotted-block of PVC. The "counters" wore-down quickly with successive bends..




So.. I machined a wider slot in the PVC block to accept jaw-plates for repeatability.




I don't know how much this stresses the bend-points. Maybe a combination of smoothing the fixture-jaws and pre-heating the mounts, just prior to bending the angles.. would produce a more solid mount? I will try it before sending any more. I will also send you some unbent blanks. You could use those for the "290 Special" model.. should you choose to build it.. or something with a similar firewall construction.