Re: 049 medallion starter springs

Surfer_kris Tue Feb 25, 2014 9:56 am

I've never had any problems with getting the prop entangled with the spring on its own, I must be doing something wrong... Rolling Eyes

On the frictionless types there should be a large enough gap between the prop and the spring so that they cannot engage on their own, even if the engine runs backwards. Half a turn is plenty of wind-back to get a snappy release and it will not deform the spring.

The Norvel springs can easily be use on the cox TD and medallions too. If you don't want to drill a hole in the engine lug, then just rotate the spring 180° and make a hole (and groove) in the engine mount.

Here is an 05RC with Norvel starter spring (no mods to the engine);

049 medallion starter springs - Page 2 Img_1322

getback Tue Feb 25, 2014 5:39 pm

I like that Kris surfer dude , I will try that set up for I really don't like the way the spring starter point ends up at the top , I am right handed but wind with my left Huh...

?? I know flipping sometime can take the fun out pretty quick DAMMIT!

also trying to get my engines to run better still some learning . Thanks to u guys it comes easier than trial an error all the time Smile

Marleysky Thu Jan 29, 2015 10:15 am

roddie wrote:I'm still laughing SD.....   (apparently your Bee's never start backwards...   )

I see people WIND THE CRAP   out of their spring starters... I usually go 1 turn. That's all it takes to produce more torque than you could ever exert with your finger (no matter how long it is..    ) as long as all else is correct (engine tight, plug lit, good fuel) Over-winding.. bends the spring-coil out of shape and affects the alignment of the tab/hook.

Here's a "zero-drag" starter used on a Babe-Bee bench-run, to test a venturi throttle's rpm range.

Roddie

The banter with my wife starts around 2:10... (if you can make it that far...   )

Roddie. - happy birthday again! Watched your movie of the "throttled 049". That looks like it works real good. Have you tried it in a flyable airframe? Don't know what fun it would be flying slow in CL, but for powered gliders or RC you could extend your flight time by idling back. Loved your wife's comments at the end of the video!! ( next time just tell her to just " go make me a sandwich ")

roddie Thu Jan 29, 2015 12:32 pm

Marleysky wrote:
roddie wrote:I'm still laughing SD.....   (apparently your Bee's never start backwards...   )

I see people WIND THE CRAP   out of their spring starters... I usually go 1 turn. That's all it takes to produce more torque than you could ever exert with your finger (no matter how long it is..    ) as long as all else is correct (engine tight, plug lit, good fuel) Over-winding.. bends the spring-coil out of shape and affects the alignment of the tab/hook.

Here's a "zero-drag" starter used on a Babe-Bee bench-run, to test a venturi throttle's rpm range.

Roddie

The banter with my wife starts around 2:10... (if you can make it that far...   )

Roddie. - happy birthday again! Watched your movie of the "throttled 049". That looks like it works real good. Have you tried it in a flyable airframe? Don't know what fun it would be flying slow in CL, but for powered gliders or RC you could extend your flight time by idling back. Loved your wife's comments at the end of the video!! ( next time just tell her to just " go make me a sandwich ")

Ah yes... and she does make GREAT sandwiches!!!! The Ace (venturi) type throttle shown in the vid has only been bench-run by me. I plan on trying it in a marine app. on a small out-rigger hydroplane. As well as throttle control; it should help to prevent engine over-speeding if the model flips over and also provide for an anti prop-cavitation aid when launching.. helping to get the hydro up on it's step and plane-out.

The issue(s) for this throttle/engine combo in a control-line airplane app. are the power to weight ratio for the reed-valve engine being marginal.. and the fact that the firewall must be designed for the plunger (needle) to pass through it's center and straight into the engines rear air-intake. On a profile fuse, this isn't impossible.. but it does pose challenges for fitting a 90 degree bell-crank and return-spring to actuate the throttle linkage for a 3rd line to control. I had put some thought into this for a 1/2A Navy-Carrier scale model. It would need testing.. and the throttle return-spring would need to be of a tension as to not be affected by the drag of it's 3rd line while holding the throttle normally full-open until the line is tensioned.. but not so much as to affect the function of the two main control lines. This would be the "lightest-weight" option as compared to a servo-driver/receiver/battery set-up; which would add too much weight to be practical (even with the lightest weight modern radio gear). Carrier models aren't required to "stunt". I believe that they are judged on "top-speed" and in turn; slowest speed (timed laps) and their ability to make an "arrested" landing on a simulated carrier-deck. This also requires a durable landing-gear. It would be interesting to try a throttle-linkage which is connected to (or actuated by..) the main bell-crank. This probably sounds crazy initially.. but if the throttle could be proportionately "closed" with up-elevator input, it may be enough to pitch the nose "up" while at the same time; bleed-off airspeed as the engine runs slower. The Ace throttle is quite "linear" in operation.. so it may be possible to dial-in using a clevis in the throttle linkage.. plus there would only be the two conventional lines to deal with. It would definitely be a "balancing-act" though.. because giving up-input at max speed will obviously cause the model to climb before it slows down enough. Whereas the model is not designed to "stunt".. it could be built with minimal elevator area.. (like a speed-model) which just might be enough to work.

Thanks again for the Birthday wishes!!

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