914 Detent

[Esser]

Rotax 914 operators, what have you been using as the 100% throttle detent? The installation manual shows a throttle quadrant but for push-pull throttles I’m curious what everyone else has done? For now I just marked in black where 100% is. It does move +- 1% depending where the friction is set...

[aviator79]

I feel like I read something about using a piece of tubing to make a detent, but I never saw details. I suspect lot of people do without it. Do the firewall forward instructions not say anything about it?

[Esser]

No, they don't I suspect you are right and I will probably end up using MAP more than anything

[jiott]

When I was training at S&R in their 914 powered Kitfox I noticed they used a piece of split plastic tubing about the same length as Josh's black mark.

[aviator79]

When I was training at S&R in their 914 powered Kitfox I noticed they used a piece of split plastic tubing about the same length as Josh's black mark.

How did that work exactly? It seems like just a piece of split tubing would just fly off when you pushed the throttle past it? Maybe the next victim at S&R in Idaho can get a picture.

[jiott]

Yes, the S&R plastic bushing would probably fly off of you jammed the throttle hard forward. Maybe this is good? It works great in normal, non-panicky flying, plus it can be fairly easily removed if you are going into an area where you know you want absolute maximum boost.

[aviator79]

Was the intent of the split tube to limit the travel except when needed in an off-normal situation, or did it allow routine use of full boost for takeoff?

[jiott]

Brian, I am getting over my head here since I am not a 914 driver but happened to be training in one. I actually don't know the real intended purpose of the S&R plastic bushing; it was mentioned that the last bit of travel was not really needed in training and was easier on the engine. I only brought it up because it seemed to me to be an easy method of limiting throttle travel for whatever reason.

[jdmcbean]

What we have learned; We really do not NEED full boost when operating the Kitfox and the 914.
We felt that Full power RPM, full MAP Boost gets things warm in a hurry and is the equivalent of stomping the pedal from the street light all the time. In aircraft we are taught to use full throttle power for takeoff..

We found that using Full Continuous power for takeoff was more than sufficient and all around easier on the equipment.. BUT operating in the back country, or anywhere for that matter.. if you NEED full boost - you want it now. We had MANY ideas but wanted to keep it simple and not have to think if needed... So we simply took a piece of tygon about .3125 in length (varies) cut it in a diagonal and slipped it over the throttle shaft. You can calibrate the length using the TLR program. Do a full throttle calibration, then simply trim down a piece of tygon until you get to about 105% throttle. Now if you goto the tygon stop you'll get about 34" MAP.. If you simply push to full throttle the tygon pops off and 40" MAP.. usually the tygon piece goes right down the flap handle hole:mad:
The concept works well and have done it on the flight training aircraft.. but carry a few spares with you.:rolleyes:

[Esser]

Thanks for chiming in John, that makes sense!

[Planesmaker]

I have a 914 in a jabiru j400,very rarely use ful power,I simply use manifold pressure. At 35" (100 hp) with wife plus kids on board (650 kg) climb out at 800 fpm. CS prop fitted. I like the plastic tube idea. Simple