Re: Pee Wee Horseshoe back plate

Jason_WI Tue Feb 19, 2019 2:42 am

I'll find out tomorrow. Very Happy

1/2A Nut Tue Feb 19, 2019 2:56 am

Hehe yessa all set for a run up no doubt, did you bake it in the oven at 180 degs?
I read up on this less shrink ideal for non flex applications, good for up to 220F
That should do the trick, I think you have a winner here.

Jason_WI Tue Feb 19, 2019 3:01 am

Here are pics of the backplate on the engine. I polished the reed seal area with 400 grit. It seals nice and engine has a nice pop when turning over. So far no oil seepage from the backplate.

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**Admin** Tue Feb 19, 2019 3:04 am

That looks really cool! Thumbs Up

I can't wait for the test results bounce

1/2A Nut Tue Feb 19, 2019 3:07 am

Good job Jason Thumbs Up

can always add two caskets to seal it up if push comes to shove.
The intake will need to be free of any possible ingestion of carbon scraps.
The stuff wears out applicator tips there is an alt. tip for this Carbon mix.
Hex head screws should do well to join the backplate to the crank case.
Post a running vid if you can.
Popcorn

getback Tue Feb 19, 2019 6:48 am

That's Sweet !! I likeie the black to , Fingers crossed to hear some noise . Shh

NEW222 Tue Feb 19, 2019 6:55 am

Very nice. I too like the black. Can't wait to see the test video or just hear of results.

Jason_WI Tue Feb 19, 2019 6:01 pm

Changed the intake area a bit. Got rid of that gear shape cutout and went with a funnel shaped inlet and another funnel shape where it necks down for the reed valve area. Hopefully the run tonight goes well and then I'll print this version to test.

Pee Wee Horseshoe back plate - Page 2 Intake10

NEW222 Tue Feb 19, 2019 6:44 pm

Hopefully the mods you made to the original work out good. I definately like the look of it.

Jason_WI Tue Feb 19, 2019 11:27 pm

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It ran until the nitro in the Cox super power fuel softened the ABS and the NVA was loose and the reed melted into the face of the reed seal area. So it shows promise just wrong material. I have carbon fiber nylon I can try. Also have POM or also called Acetal.

I only caught the last few seconds of the run but YouTube is being cranky. Here are pics of the meltage.

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NEW222 Wed Feb 20, 2019 6:46 am

Oops. But on the bright side, it did show promise and run!

getback Wed Feb 20, 2019 6:51 am

IT Ran !!! ++++ How was the short run ? Performance wise .

Jason_WI Wed Feb 20, 2019 12:50 pm

I don’t know. By the time I got the needle set it was starting to die. Slowly melting.

**Cribbs74** Wed Feb 20, 2019 5:52 pm

Well, now you know. How much is all this material costing you?

Jason_WI Wed Feb 20, 2019 5:59 pm

The CF ABS print above was 1.25 hours of print time and about $.30 of material. However it proved the concept worked so it wasn’t considered a failure. Just poor choice in material.

The CF nylon spool I have was a sample from a filament extruder that was free. PLA is about $.02 per gram. Standard DuPont Zytel is $.09 per gram.

**Cribbs74** Wed Feb 20, 2019 10:16 pm

Could you possibly cut off small strips and test fuel compatibility before printing? Might save you time and a little money.

halfpilot Thu Feb 21, 2019 11:22 pm

Well done Jason! Excellent work.

I should really follow this forum more closely. I did some test mills on my hobby grade CNC machine last year with the same 020 backplate in mind. I was milling them out of a solid chunk of hdpe since that is what glow fuel bottles are made of. Unfortunately HDPE either melts or chips when being milled. Chips are what you want when milling HDPE but they lead to a lightly faceted texture all over the product which caused dimensional issues in the reed seat area. I also realised I hadn’t considered the heat from the running engine in my material choice.

Mike1484 Fri Feb 22, 2019 7:55 am

What material are the .049 back plates made from ? Jason , these .020 horse shoe back plates are going to be the new hot thing in the Cox world . I would think nylon would work for these back plates .

Mike1484

ticomareado Fri Feb 22, 2019 10:08 am

You dah man, Jason!

ticomareado Fri Feb 22, 2019 10:10 am

I guess the plastic should be the same Cox used on their PT-22s and .020 helicopters.

Kim Fri Feb 22, 2019 10:46 am

ticomareado wrote:You dah man, Jason!

TRUTH !!!!
We may have to petition the Admin to create a C.E.F. Hall of Fame !!!!

fit90 Fri Feb 22, 2019 7:18 pm

Kim wrote:
ticomareado wrote:You dah man, Jason!

TRUTH !!!!
We may have to petition the Admin to create a C.E.F. Hall of Fame !!!!

I second the motion

Jason_WI Sun Feb 24, 2019 1:39 am

Sometimes things go bad when changing nozzle sizes on the 3D printer. Almost new .4 mm plated copper nozzle twisted off in the heat block. It started to squeak when tightening it up. I stopped and tried to turn it out and this happened. Good thing I have spares on hand.

Been fighting nylon and the .25mm nozzle all day. Jamming up. I tried to slow down the print speed without luck. Back to .4mm nozzle and .2mm layer height for the backplate with nylon.

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getback Sun Feb 24, 2019 6:43 am

I seen that pic and thought man that back plate had a BAD melt down , well glad you had a back up , Hope you can get the nozzle size figured out for the right layering . Popcorn

rsv1cox Sun Feb 24, 2019 6:50 am

That picture Jason resembles some of the engines I have been working on lately.

Bob

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