Pee Wee Horseshoe back plate

https://coxengines.ca/cox-.020-venturi.html

http://www.exmodelengines.com/home.php?cat=249&sort=orderby&sort_direction=0&page=2 A sponser.

Need to beef up the mounting leg area. One broke off removing the print from the bed.

Check out this project:

https://www.thingiverse.com/thing:3457716





I have asked if this will hold up to nitro 25 to 35%
The E version flies very well with 3 times the power of a TD, many folks have started to print
and fly the electric version with no issues thus far. The weight of the E version is much more
due to batteries and still floats in fine on landings. Direct engine exhaust is going to melt that
firewall the designer is going to need to compensate with a heat shield or muffler.

Maybe some aluminum foil tape over the front would help scare away the heat. That mount looks nice. A CNC mill would be handy to have to make an aluminum mount. Maybe work a bit of overtime to save up :-)

HVAC aluminum foil tape should work. Could also print out of PETG that has a higher tg than PLA.

I expect a flight vid at some point he has posted his E version 3wks ago, will post the link
when it happens. I have some of that aluminum tape too, the sticky will unstick but if glued
on it wont go anywhere. Yes the entire project is done with PLA.

NEW222 wrote:That sound nice. I cannot honestly remember if I had ever heard an .020 run before. If I may ask. What is a 'venturi backplate mount'? Is it the second one you had posted a picture of? If so, where does the needle assy go. That part has me confused. I would be happy with just the standard one, unless there is something I do not know or understand with the function of the second one. Will be watching for sure. Keep up teh good work!

I’m trying to replicate this setup with the venturi backplate mount.




Good news I found my 11/64-40 tap. I had used it to tap the backplate on the engine above.

That is good news onward ye goes!

1/2A Nut wrote:Check out this project:

...................:

Wow man this is beautiful, reminds me of my TeeDeeVooDoo. Any idea how much this Nucking Fut ( ) project weighs with the glow engine in the nose?

That aluminum mount is pretty cool, but requires quite a bit of strength from the material used.

For a plastic version it might be necessary to make a "flange" style mounting surface similar to the birdgage mounts used on Thermal Hopper. Maybe also increase the radius of the bases of the "legs" to spread the load to a bit wider area.

In any case, it is quite mind-blowing to realize that you can print the sealing surface and the retainer groove of the reed system with adequate accuracy and surface quality.

I’m trying to replicate this setup with the venturi backplate mount.




Good news I found my 11/64-40 tap. I had used it to tap the backplate on the engine above.[/quote]

Could the Carl Goldberg .049 postage stamp backplate mount you made be resized and adapted to go over the venturi style pee wee back plate? Or, could they be combined? I know it is really easy for me to type this stuff. I can only imagine what it is like to be doing what you are doing.

I knew when I beefed up the mounting tabs things would be pretty tight. I’ll have to open up a little bit to make room for the NVA. Also need to make the lugs a bit deeper to make clearance for the venturi to the firewall. I’ll test it as is to see if there is any better performance.

How much does that assembly weigh with engine?

Shortened the overall design while lengthening out the legs. Shrunk the diameter a bit. Should be lighter too. Can't use the standard 2-56 x. 75' length screws with this design though. Hopefully its still strong enough.

Video run of the latest version of the venturi mount. Still need to add clearance and possibly solder an extension on the needle valve. I can’t make the mount any thinner for fear of breaking too easily.



Here are a few pictures.

That sounds and looks great!!

Wow. That doesn't even look like it was 'printed', but rather pressed in a mold. I really enjoy seeing your pictures of stuff you print.

Its definitely printed. .1mm layer height or 100 microns. I believe I can get better resolution using .9 degree stepper motors vs 1.8 degree stepper motors on the X and Y axis. Less artifacts when micro-stepping in the firmware of the printer controller.

The second picture shows the support material removed. Without support the overhanging parts couldn't be printed. The brim around the legs help keep them adhered to the bed. Nylon likes to warp. I chuck the venturi mount in the lathe to give the surface area where the NVA seats a flat surface. I can shorten this tube now by .2" to save material. I made it longer to adjust the offset of the NVA.

1/2A Nut wrote:For sure should have more performance with that setup, could also use a GM .030 RC Carb

It might just fit.