N331PC

Hi guys I’m new to this forum, well forums in general!!

But here is a quick question....

I have been designing flying wings for a few years using electrics, and have had pretty good successes.

Just recently i found a nice Tee Dee .049 stashed in an old RC parts box, and was inspired to throw it on a wing!

As a pusher!!?

after a little thought, i realized this may not be possible because the carb will be facing down stream creating a vacuum instead of receiving ram air as it would as a tractor
.
So if any one has experience with using nitro engines as pushers (particularly Cox .049s)
It would be great if I could get some info or a
Go or no go

DICKEYBIRD

Sure, it'll do great! The venturi issue isn't a factor. The 2 main issues are the prop driver thrust washer and cooling. Very early Tee Dees had a phenolic washer which is OK but not as good as the the nice, hardened steel washer that's on most of them. In either case, put a drop of oil behind the prop driver before startup and you'll be fine.

Set your needle a tad rich and the overheating shouldn't be a problem. If it does get too hot, try to find one of the clamp on heat-sink head adapters from one of the Cox cars and that'll fix it.

Oh, make sure you get a pusher prop!

old git

This is the most important part. The rotary valve TD runs one way only, try a cheaper reed valve Cox.





old git - - - - - - - - aka John L.

skaliwag

My Feedback: (1)

Or get a Reverse Crank

build light

And of course you know what happens if you get the reverse crank and use a lefthanded or clockwise prop!

Robert

combatpigg

My Feedback: (3)

Grish pusher props rule, but they don't seem to always be ready to take orders. Don't hold your TD pusher peaked out on the ground very long, get it set and into the air pronto! I think running them on bladder is the best way to go......I don't like the engine to go rich when the model is climbing, which is what happens with a suction tank ahead of the engine.

jetpack

My Feedback: (1)

One suggestion I would like to make, if you'r going to dig into the motor with thrust washers, make sure the end play of the crankshaft is at its bare minimum. Most TD's have enough room for two phenolic or a stainless with a phenolic.

When the prop hub and crankshaft is pushed against the motor with too much slop, it carries the connecting rod with it, causing the rod end not to sit square to the crankpin, and cause rapid wear and stretch. Everything is designed to align with the crankshaft all the way forward.