Throttle Springs Revisited

[RFSchaller]

Good discussion, and I agree with the comments on synchronization. I just posted it so that those of us who use alternate springs are aware they do break. The wire diameter on the HF springs was about half the ROTAX diameter. I don't know about the materials differences.

[pietermk]

Originally Posted by David-aviator

There are many, many Lycoming and Continental engines flying for decades without springs. So why does Rotax have them? It is because they have no confidence in their push pull throttle cable design.

I have had one flight behind a Rotax and hate those springs, that I know for sure. I empathize with those you who have live with them.

David, the throttle springs are not a Rotax design, it is Van's design. I have flown many LSA's with Rotax engines and noon of them have the springs like the RV12. it was a safety design feature.

Peter

[rvbuilder2002]

Originally Posted by pietermk

David, the throttle springs are not a Rotax design, it is Van's design. I have flown many LSA's with Rotax engines and noon of them have the springs like the RV12. it was a safety design feature.

Peter

Actually the springs used on the carbs, on the RV-12, are the springs that are on the engine when it is removed from the crate (supplied by Rotax).

[David-aviator]

Originally Posted by pietermk

David, the throttle springs are not a Rotax design, it is Van's design. I have flown many LSA's with Rotax engines and noon of them have the springs like the RV12. it was a safety design feature.

Peter

The Rans Coyote has springs, I believe Rotax invented the feature on the 912 engine.

[sandpiper]

The Flight Design CT has springs. It also has a throttle quadrant. The throttle is easy to move and stays put. There is no in flight adjustable friction but it can be adjusted on the ground in about 5 minutes. I've had to adjust it once in 7 years.

[paul330]

Springs for a critical engine component changed for ones from Harbor Freight? Really.................

[Dave12]

Originally Posted by paul330

Springs for a critical engine component changed for ones from Harbor Freight? Really.................

Hate to be critical, but I am with you. I have the original cable and springs and just don't really understand what this discussion is about. If it took 5 minutes to get used to this throttle, I don't recall it.
For the sake of everyone, when you contemplate a mod, consider then re-consider everything you do. If you are not sure, seek consultation from the more knowledgeable. They are here and willing to help.

[roger lee]

The springs were a safety feature from Rotax and they do two things. First they help normal throttle operation by helping pull any slack or slop out of the cable and helps both carbs to stay a little more equal.

If a cable or linkage breaks that carb will go wide open and not shut down (like on an approach). If you're flying and your engine starts to shake really bad then one response is to try WOT and if it smooths out then you know a linkage on one carb is broken. This feature will allow you to fly to a safe place and land on your terms. Yes there will be a point you have to shut the engine off, but it is on your terms and place. If you disconnect these springs then if anything happens to the carb linkage your done flying and your landing and not on your terms. I have seen a few people reverse the springs to pull the carb shut and that's another poor decision.

If springs are causing anyone problems then fix the problem not the spring. Some throttle setups in some aircraft aren't the best design.

[Flyer68]

I recall seeing an ad for weaker Rotax springs. I believe if you called Rotax they could tell you if there are weaker factory springs available.

[bobnoffs]

is it rotax or bing? my jabiru has that spring and the throttle cable is solid wire , so it is not to take up slop in that case. and this brings us to the question of why cont. and lyc. don't have them.