12V Linear Actuators

[Skippydiesel]

This is directly related to an aviation project.

I seek your recommendation for the supply of quality/robust/durable mini 12 volt linear actuators, with a 20-25 mm extension capacity.

Have tried the eBay offerings, lasted 1-30 hrs - not good enough!

I await your responses with interest.

[gammaxy]

Do any of these actuators at McMaster-Carr make sense? https://www.mcmaster.com/products/linear-actuators/

Something like the "Electric Actuators" or "Compact Stepper Motor Actuators"?
https://www.mcmaster.com/products/linea ... tuators-5/
https://www.mcmaster.com/products/linea ... actuators/

[ampzapper]

I don't have first hand experience with them but I know that some people have sourced actuators for flaps from Firgelli Automations. On the US version of the site they have some micro pen actuators rated for 60C with a 1 year warranty.

[Skippydiesel]

Thank you both -

I checked out the McMaster web page - nothing in the mini class (retracted overall length under 80mm).
Firgelli no longer seem to offer mini linear actuators - I have an old (discontinued ) one on my desk in front of me.

I guess if I can't find a suitable unit, in the mini class, I will have to redesign/build a new mounting system.

Thanks again.

[BRS]

I have been using this actuator on my Flaps. have not had a lick of trouble with it. What is cool about this model is that if you are careful you can disassemble it and modify the length of motion. Not sure where I purchased it.

[Skippydiesel]

BRS - "Looks the Goods"

My current mounting system is for a closed/retracted overall length ot 70-80mm and an extension of 20-25 mm.
The 20-25mm extension is not hard to find but the 70-80mm closed length seems only to be available through Chinese suppliers.
I have tried two, from a supplier called CaryMart - both failed in the fully extended position. The first after about 30 hrs use, the second only 1 hr.
CarryMart are a Chinese supplier. The only reason I went with them was because they appeared to have comprehensive specifications.
They are up to x 4 the cost of very similar offerings on eBay. An additional negative 30+ days from order to dispatch - another 10 days to deliver.
The first CaryMart unit was "postmortemed" - motor still good, extension mechanism still good, electronic drive/movement limiter switch failed. Very small printed circuit - no hope of a home repair.
The limiter switches protects the system from stalling, at the end of extension/retract strokes, cutting power to the motor. To retract, the current polarity is reversed at the switch. The failed limiter won't allow the reverse polarity to connect with the motor - hence the fail in the extended position.

[karmarepair]

Progressive Automations seems like it might have the goods.

[kmacht]

For those of you designing electric flaps off of a linear actuator, what are you doing to prevent a runaway flap or the ability to retract flaps if the motor dies? I like the idea of electrics flaps but would never want to be in a situation where the flaps went full down uncommanded without any way to bring them back up. Has anyone come up with a manual override of some sort?

[karmarepair]

I've flown lots of Cessnas with electric flaps, and not one had a manual over-ride.

[BRS]

Uncommanded down fault would be quite a stretch, though I guess possible. Putting the flaps down and having them stay down would be more likely. The good thing is, that the flaps don't go down unless I'm landing. The odd's that the flaps stick down and me doing a go-around/abort-landing would be worst case scenario. It would be most unlikely that I would do an abort the same day the flaps stuck down. Yes it could happen.

Comparing the sonex to a Cessna in this regard may not be quite fair. A more important question would be "Can the plane climb or at least maintain altitude with the flaps down. I don't know as I've not tried it but am certain to do so on my next flight (If I remember). Those of us with 80/85 HP might not be able to climb at all but those of you with 100 HP are likely to have better success. I'm wondering which Cessna's will climb with flaps. i know the Skyhawk (at least one model) will climb.

Story: Years ago I was in the back seat of a skyhawk (all seats full) to act as ballast for a student doing a gross weight checkout (I too was a student). The instructor called for a go-around which the pilot did but the plane was climbing very slowly and all on board was concerned. We got around the pattern with full flaps, landed and parked. Turns out a mechanic had left a wrench behind the panel and it jammed the flap mechanism, although the flap handle moved up nomally for the pilot.