A simpler / cheaper .049 Tee Dee Engine suggestion

His site lists only 5 crankcases in stock.
That would imply those have to be made.
Even if he has enough of the other 2 parts the cost savings of simpler machining alone would be worth it.
The result would still be fully compatable with the other stock parts.

Yes, I was thinking that the aluminum housing instead of the plastic one, could be drilled smaller like the Medallion and use a needle from the reedy that presses in. Likely the thought is that the guys want something nostalgic, so the marketing might make other decisions to keep it original. I think the plastic seals better than the aluminum part, although they always cracked at the venturi. It would take fewer parts to change the housing though.

TD .020 / .049 CNC cases with bearings would be hot aftermarket hop up offerings.

Can go with the stock screw in venturi and valve assembly to keep cost down.
Stock prop plate can still be used. Just the bare bones case and bearings.
Radial mounted will cut cost of having to waste material with protruding beams.
Will run cooler, produce more rpm and take some load off the ball socket in 3 ways.
Prop vibration greatly reduced and the associated wear / heat on the crank case.
Fuel air will be cooler providing a denser power charge due to the bearing supported crank.
Strong TD power is likely with a APC 4.6x3 / 5.5x2 / 5.5x2.5 glow props / APC 5x3E
With bearings can opt for low compression and larger dia. props for slow fly / FF.
The bearings should help swing 6 and 7" props with gusto.

 

cmulder wrote:His site lists only 5 crankcases in stock. That would imply those have to be made.

I've been checking the site periodically over the past several months, that is new,   he might have withdrawn the rest to reserve for the proposed production run.
Don't you think?

Is the outside diameter of the crankshaft a standard bearing size?
And what outside diameter would such a bearing have; would it fit in the original outline of crankcase retainer nut?
If so then part of the run could be the original sleeve bearing and with just a diferent gcode file the case with the cutouts for the bearing could be made.

Also how expensive are good bearings in that size?

GallopingGhostler wrote:

cmulder wrote:His site lists only 5 crankcases in stock. That would imply those have to be made.

I've been checking the site periodically over the past several months, that is new,   he might have withdrawn the rest to reserve for the proposed production run.
Don't you think?

Hording and avoiding potentional sales that could fund the production of new stock...
Would you assume the total profit would be higher on a completed engine compaired to selling the parts by themselfs?

Good Idea Brad but probably wishful thinking , I have heard Bernie say they don't put stock at the level they have say if they have 1000 in stock why do you need to know that ? Would appear as a slow moving product or to make you think they Only have a few in stock !?!?

Think about it.
What would be a reason one would buy a crankcase?
The only reason i can think off right now is having almost enough parts to cobble togeather another engine but are just missing the case.
If the case of a engine is worn to the point it affects performance is it then not also likely the cylinder and piston are worn too?

So i doubd these sell a lot so this makes me asume the stock level indication is genuine.

On the other hand how many would buy a ball bearing upgrade case if it improves performance?
For sure i would be on that list and swap the parts of a stock engine to it.

Improve the performance? If I wanted to do that I'd go AP or Norvel and call it done.

If to keep a nostalgia plane in the air, I'd want the nostalgia engine. I'm starting to like the idea of less performance from the engine, and more from the airframe.

The whole point of selling the ball bearing case as a upgrade is that it gives people a choice.
Pressing in the bearing likely increases the cost to much for a complete engine.

And then the upgraded engine would still be compatable with the pile of spares i have and a exact swap on the models i like a bit more power on.

Right now it not a good idea to show up at our club field with a norvel engine....

cmulder wrote:Is the outside diameter of the crankshaft a standard bearing size?
And what outside diameter would such a bearing have; would it fit in the original outline of crankcase retainer nut?
If so then part of the run could be the original sleeve bearing and with just a different gcode file the case with the
cutouts for the bearing could be made. Also how expensive are good bearings in that size?

Can paint a picture with 3D printed case, see pic below - CNC aluminum can be much leaner in size.
Bearings can and had been found during some 3D printed testing with Tee Dee parts.
Testing showed the metal insert was migrating in the printed case.

I don't recall the name of the thread on CEF at the moment but did save a pic.

Do you know if the guy who makes the screw in radial mounts has a cnc machine that could make these?
To save cost just supply the bearings separate for the end user to press in themselfs.

I have brought it up a few times. It's out there for potential / for the willing.
Could have it billet milled or printed in metal these days from sites that offer
prototyping and small batch work. TD .020 case would be a real treat with
screw on radial mount backplate and bearings.

Titanium printing:
https://www.stratasys.com/en/stratasysdirect/materials/metals/titanium/titanium-ti642/

TD CAD files here:
https://grabcad.com/library/cox-tee-dee-motor