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Author Topic: Another attempt to avoid work.  (Read 478 times)

Offline Mark Mc

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Another attempt to avoid work.
« on: November 17, 2022, 11:02:47 PM »
I was unpacking another box of modeling stuff and one thing that came to the top is a new Brodak 1/2A engine mount.  I love these things and use them for a majority of my 1/2A profile planes.  They work great, but theyíre limited to Cox tanked Bee type engines or the horseshoe engines.  And, although I havenít tried it, it should work for the Testors 8000 engines.  I have probably 15 or so planes with these engine mounts.

Another thing Iím finding as Iím unpacking and looking for space to put everything is that I have entirely too many Cox engines.  At least 10 to 20 times as many as Iíll ever use.  Since one of things my wife and I are trying to do in our new house is to cut things back to the minimum to prevent clutter, Iím going to cut back on my engines.  And since Iím in love with bladder pressure, Iíll be cutting back severely on my tanked engines.  I think I want to end up with a majority of rotary valve engies vs. reed valve engines.  Not that I donít love my Bees and postage stamps, but I donít need more than five or six tanked and a couple of plastic backplate engines.

The thing now is, what do I do with all the planes I built for the Brodak mounts?  Okay, time to put off unpacking and go to the parts box I already unpacked.  I have a couple of the Texas Timers .049 TD/Medallion radial mounts in the bladder drawer waiting to be used.  HmmÖ  Okay letís take the new Brodak mount and see how the TD/Medallion radial mount fits.






Awesome!  Letís see how it looks with a TD .051 with Kirn Kraft needle valve.






Awesome≤!  I can get a couple more of the radial mounts and have two TDs and two Medallions that I can swap out between the different planes.

Texas Timers no longer sells these radial mounts for the beam mount engines.  But, these are now being  made by Kamtechnik.  Kamtechnik also makes the radial mounts for the TD .09 and .15, as well as the Norvel .049/.061/.074 engines.

Mark

Offline kenneth cook

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Re: Another attempt to avoid work.
« Reply #1 on: November 18, 2022, 05:44:58 PM »
                  Mark, Brodak makes two kinds of those mounts. The one your depicting there is of a plastic which is somewhat beige in color. I use that mount but it's a harder plastic which I've had crack around the screw holes which retain the engine. Brodak makes a identical mount which is more of a translucent look which is white and is a lot more flexible. I've found that particular mount to be more durable and the ones I've had are now going on 10 years. I saved the one in a bag but the funny thing is it's the same number as the beige version.

Offline Mark Mc

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Re: Another attempt to avoid work.
« Reply #2 on: November 18, 2022, 08:48:31 PM »
Ken,

I've only seen it in the beige color.  So out of curiosity I just looked at the Brodak website.   It doesn't show a white 1/2A mount.  It doesn't even show the beige mount. The only mount they have is now showing as black.  Hmmm...

Offline Larry Renger

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Re: Another attempt to avoid work.
« Reply #3 on: November 19, 2022, 12:38:14 AM »
I designed that mount for Brodak, and it was supposed to be virgin Nylon 6-6. Those are almost bulletproof. The Devil is in the details as this and the latest batch of ďrubber duckyĒ props show by bad plastic choice or molding techniques. Bend one and you will see surface cracking. I am not brave enough to test such a prop by running it. Sorry, that is my observation. I would love to have the original bullet proof props. Virgin 6-6 Nylon with no regrind and careful mold control do the job.

Sadly, I donít recall the percent of glass to make the gray props. It has been nearly 51 years ago for me and I probably never had that information.It was, then, a big company and I designed models and had nothing to do with production.

At Cox, when I was there, molding props required our best practices. Liability suits could result from less than the best.

We tested our 7x3.5 to 50,00 rpm because they were being used on super high powerful .15 engines instead of Medallion .15 sport engines.

Motor mounts are not so critical, but they could certainly be improved with a bit of carbon or glass fiber in the mix. But durability versus rigidity is a tradeoff to be considered. Tough trainer or precision flight. It would be nice to have that choice. Trainer and Professional versions. Not too hard to sell both. Just change the mix going into the tool.

Perhaps a racing group could request a special mold run. At Cox, we did the Kiler Bee and .051 Medallions to fulfill special Free Flight model groups. I donít think we lost money doing it. The resulting volume and prestige were worth the effort.

« Last Edit: November 19, 2022, 08:07:29 AM by Larry Renger »
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline Dave Hull

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Re: Another attempt to avoid work.
« Reply #4 on: November 19, 2022, 06:05:20 PM »
Good info, guys.

Here's another couple of data points:

I have I think four planes flying (there may be more...) with the Renger/Brodak plastic engine mounts. Two are the milky white jobs, one of which is about 10-12 years old. I flew it on a Stop Sign just last weekend. No structural issues so far. Two others are the beige material. One is on a "new to me" plane--a Baby Clown built by Jim Leuken. No problems with the beige ones yet either. I wouldn't be afraid to use either, even used ones, as long as they weren't cracked when they came off the donor plane.

As an alternative, Accurate Models of Renton Washington (206-909-9186) is now making a barstock aluminum mount with threaded holes for machine screws, which were supplied with the unit. Available in either Horizontal or Vertical backplate orientation. I bought one from racer Bill Cave of California recently. Not inexpensive, but a very nice piece! (Let me see if I can post a picture or two....)

Dave
« Last Edit: November 19, 2022, 07:07:08 PM by Dave Hull »

Offline Dave Hull

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Re: Another attempt to avoid work.
« Reply #5 on: November 19, 2022, 07:15:14 PM »
Here's a view of the back side of the Accurate Models engine mount. It has a nice bead blasted finish everywhere except the front side for engine mounting. The front is also relieved for better engine breathing. Weight is 14 grams. There is no engine offset or provision for landing gear attachment. I will probably use this on a Mouse racer. We nearly always use a single strut gear mounted well aft of the firewall for best handling.

Offline kenneth cook

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Re: Another attempt to avoid work.
« Reply #6 on: November 20, 2022, 05:48:15 AM »
           Certainly a nice piece there Dave. I did find my mount as I put it aside. However, as Mark mentioned, the new ones are black plastic. Who knows maybe they changed the formulations through the years. When I mentioned the beige mount, I've had more than one of these fail and not from ground strikes. They were in storage and dried out and I noticed the splits that formed around the screw holes. These mounts however are probably 12 years old or better. Certainly not a complaint more of a observation.  I just happened to notice that the milky white ones were more flexible. What I also noticed is that the mount that came with the Brodak Baby Clown ( First edition) is extremely flexible . They're also a tad smaller than the Brodak mount. I can't post pictures on here as I find it to be a pain in the rear.

         I use the radial mounts all the time and have been doing so for years because I don't care for  the Dave Brown mounts. I used the Dave brown mounts early on for combat and had more of them fail then I can count. Not only did they cause vibration issues, they would break where the screws passed through. One way to avoid this was to just drill and tap the material for 2-56 screws. Using the supplied sheet metal screws would immediately cause failure in short order as it would swell the material and the failure would occur right on the screw penetration.  This was probably and more than likely due to the taper of the screw forming a wedge.  I had purchased a cast aluminum version somewhat  similar to the Tatone cast aluminum versions but much much lighter. I use those for stunt as they do the job well enough but I seriously doubt they would tolerate a ground strike.


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