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Too many variables so need to brain storm

professor229

New member
Hi..... From the beginning... I am number 095.... It is a 24 year old restoration... took four years. Experimented a ton but that's half the fun... I originally had in the standard manual lift tubes from the factory in Oakland.... They worked very well.... and for a few years I used to manually lift the canopy but wanted a cool factor. I ordered 8" SPAL linear actuators... made my own mounting brackets (love to design and fabricate) and left the manual lift tubes in place so the linear actuators should have been lifting VERY LITTLE weight.... This was OK... worked for a number of years.... had the operation on a dash mounted toggle switch.... and then added a remote control unit from Dana German; kind of custom made at that time. It also worked well... The wow factor in a parking lot when you opened the canopy from a distance was something else... Lately, that remote has not been working all that well... I did some troubleshooting and have it better but think "age" has taken its toll on that.. The toggle switch still works great. I replaced the SPAL actuators a few years ago but I am not all that happy with them. TOO SLOW!!!! So I have been researching.... My current actuators lift at 14 mm per second (half inch) so for an eight inch stroke it is taking 16 seconds which is OK .... but.... I found some used high speed units on Ebay and have been researching them... I just found out that a fully intact canopy with glass is about 250 pounds, but as I said, I left the original lift tubes in place and the linear actuators work in conjunction with them.... I remove the top bolt from the actuators and still lift the canopy using "armstrong" and the original tubes still hold the canopy up fine... and it is easy to lift.... the problem is the time it takes to lift it now with the Chinese specials I bought..... So... I am considering these....


The distance from the top and bottom holes are an inch or so longer than the current actuators so I will need to goof off with that a bit... not a big problem... but if you look at the lift time under load it it is better than 2 inches per second.... four seconds to get the canopy up in the air and down.... The force is rated at 100 pounds but there are two so that would lift 200 pounds and with the existing original tubes in place..... and since the canopy is counterbalanced and weighs essentially... well.. nothing... these actuator should work fine...

The plan is to buy two of these for $110 and then bench test them... and install them after reworking the mounting brackets.... and cross my fingers.... If they work as stated, I will buy at least one more to keep on the shelf just in case of a failure....

I went to the original company's website to read all about these and they are Canadian I believe....

So my question.... What am I missing? I even checked out the bolt hole size on both the top and bottom openings and they will work with my existing system.... I just want to ask if anybody sees something that I have not considered.... or should consider..... All suggestions/thoughts appreciated... Thanks Dennis...

PS.... I got the car out of its storage home two weeks ago and did a bunch of maintenance on it and also spent some time adding a polymer coating to it.... and of course I have torn into the linear actuator controls to make sure the connections have not corroded... they all looked like the day I put them together....

Have a good one.....
 

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farfegnubbin

Site Owner
Staff member
Hi, and welcome! We'll all be eager to hear and see more about your project.

I like the logic and strategy of what you've tried. And it's not unprecedented. We've had quite a few builders who have switched to linear actuators along with their attendant pros and cons. (It seems like a lot of the Eurekas in Australia use linear actuators.) Keeping the original gas springs definitely should help lessen the weight that the actuators have to lift and should therefore speed things up a bit, all else being equal.

Reading down through your post a few times, I wouldn't say there's anything major that was "missed." I've been working on a new lift mechanism which will eventually be available through the company and here are a few metrics that I can fine-tune.

1) The total weight of a Sterling canopy with windshield, side glass, and entire wiper mechanism is about 130 pounds. I have actually weighed that exact assembly, photo below. (Note: I had one side window removed but I weighed it individually and added it in later.)

Weight of Sterling canopy.png


2) But because the attachment point for the hydraulics/gas spring/linear actuator is only a fraction of the way between the lower and upper hinge point, the effective weight of the canopy seems quite a bit higher. It's difficult to accurately measure the effective weight (or to calculate it because the mechanism is an uneven parallel arm hinge setup) but I've estimated it to be a little higher than 300 lbs based on the fact that it seems to require gas springs of at least that amount to make the canopy feel "neutral" by hand. So the amount of force you need the linear actuator deliver depends on how much work those gas springs are doing. It's true that if the gas springs are doing most of the lifting, the linear actuators don't need to be terribly strong. (Obviously if a builder is using linear actuators alone without any gas springs then the actuators must be quite a bit stronger.)

Other things to consider that people have noticed and played with over the years:
a) A linear actuator that isn't rotating is basically a big, strong bolt. Be sure you have a strategy for an escape mechanism. With hydraulics, you can always install a dump valve or cut a line. With a pair of actuators you should find a strategy that allows you to quickly unhook the top or bottom of the actuator in an emergency in you need to. (I was ALMOST stuck in a Cimbria with actuated gull-wing doors EXCEPT that the very insightful builder of the car, Fuzz, had the foresight to put pull-pins at the attachment points.)

b) Hydraulics kind of self-sync between both sides but this is not necessarily a given for linear actuators. If you have two that are rated the same you might get lucky and they might always run roughly in sync. The clutches on most actuators might also compensate for this insofar as, even if things lift unevenly, the faster side might just happily clutch out when it hits its endpoint. There are electronic ways to ensure a set of actuators are in sync, but those details are beyond my own knowledge base.

My cars have always had electro-hydraulic systems and I haven't personally played with linear actuators much. Other members might be able to help you with specifics.

Again, your general strategy seems just fine! And I agree that the target lift time should be somewhere between 5 and 10 seconds. I don't really want it to jerk or crash open. But I also don't wanna wait 20 seconds. The canopy is already spectacularly dramatic by its very existence. Having it go up too slowly seems like a scene out of Austin Powers.

("Take him to the unnecessarily slow torture device!!")

Looking forward to more pics and stories. (y)
 

letterman7

Honorary Admin
Welcome Professor! If it's who I think it is, hi there from years past! We've talked quite a bit over the interwebs as I got the National Sterling Owners Association started - you were one of the first in! Good to see you here Dennis!
:)

Rick
 

professor229

New member
Pretty car, BTW.

Do you know what the donor was for those side mirrors? They're nice!
Good morning.... I would have to look back or research them a bit but they are common mirrors used to extend the view for towing applications (Ebay). I bet I tried ten sets of mirrors from swap meets etc. and some from JC Whitney too.... none of them would defeat the rear fender flares on the Sterling until I found these.... and then let the trial and error begin.... I also added large convex mirrors to the passenger side mirror. I had to get some heavy duty "plastic" to add to the window opening for these to mount too.... I can take some pictures of that too.... if you would like to see them.... They work extremely well...... Of all things. a few years ago I was visiting yard sales and found a used pair for $5 or so.... I now own them and they are on the shelf.... I had a custom color rattle can of "sovereign blue" paint mixed up and sprayed them... not the best but very acceptable.... I just looked and could not find them on Ebay but if I get around to it today, I will dig out the box of leftover parts where a set of these are located and see if there is a name on them....

I am still debating the higher speed linear actuators..... I mean, $110 is pretty acceptable because I have not done any upgrades on this car of well over 10 years now.... but my current linear actuators work fine and there is the old saying... if it works, don't fix it.... I did go the Mercruiser hydraulic route and bench tested it etc.... but I worked in an industry that uses a lot of hydraulics and had to fix hydraulic problems way too many times so I decided to go with linear actuators instead.... with no regrets....

Thanks for your thoughts on the actuators and especially the information about the weight of the canopy with glass.... I was thinking of hooking something like a fish scale to the canopy and pulling on the scale to see how much force it took to open the canopy.....

Have a good one.
 

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professor229

New member
Welcome Professor! If it's who I think it is, hi there from years past! We've talked quite a bit over the interwebs as I got the National Sterling Owners Association started - you were one of the first in! Good to see you here Dennis!
:)

Rick
Hi Rick... it's been a few years.... life got in the way for me but I still own the car.... I have been restoring quite a few cars/trucks/boats in the last few years but now, I am pretty much retired... my latest is a 1995 Chevy pickup.... that I use to pull my fishing boat.... but I have lost interest in that as well..... We moved from SE MN (rural) to the twin cities (Moundsview, MN) and I went from a four car garage to a two car garage...... not good.... and there are "ordinances" here that prevent a lot of out buildings so I found an old enclosed four place snowmobile trailer, restored it, and beefed it up to hold the Sterling for four years... This past covid year, I had a shed on the property that was 12 feet long.... a do it yourself Menards shed completed by the previous homeowner, which was not long enough to house the Sterling.... so I bought the frames to add another four feet onto the shed, beefed up the floor and that is the home to the Sterling now.... no more ramps.... and it is perfect... I also paid to have a ton of work done on the motor... solid state ignition was installed... I put new disc brakes on the front..... and they still are not completely right but good enough.... I do own a back up camera system that needs to be installed and also a limiter push botton device to stop the actuators where they should... both are still in the boxes.... no ambition.... I also have restored two boats, sold one and kept one... I fish a lot these days and also took some time off to do some serious genealogical research....

Take a look at a few of the last projects..... and as usual, I wish I could have kept them all.... The Sterling is still the most "rare" restoration so that one will stay in the family....


 

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professor229

New member
Just an update on a couple of things before I head to the lake to chase some fish around this morning.... I am still debating the high speed linear actuators and I found a reason NOT to buy them...... I went to the original manufacturers website where they had the diagrams/info on this one. The distance from the top and bottom mounting holes is about 16".... My current units are just slightly less than 12" retracted.... That means that I would have to make a mounting hole four inches further down the side of the car... I don't think I have four inches... That might be accomplished with a more severe angle on the mounting.... It might be an option but will take some time/measurement/ambition... Did I mention I was going fishing?

Also... Just an FYI.... When I struggled to find decent/functional mirror for the car that didn't look awful, I eventually found a pair of the mirrors that I spent a considerable amount of time fabricating the mounts for them. They did NOT look right on the side of the car.... nor were they functional. They did look right in the corner of the window opening which meant another small panel needed to be fabricated and attached.... then the cut down mirrors would be able to attach to it.... It took several tries and cuts to get the mirrors right... They are adjustable, manually... but once set for you.... they work great... no more guessing at the blind spots... I found the extra set I bought at the garage sale for $5 and there was no label on them and no box.... but on one mirror it had "mirror mirror towing mirror" and when I googled that I found them.... Here is just one link to them and it has the company name etc... and I am sure you can find a better deal..... I also found the folder with about 30 pictures of the fabrication of these. I always documented my builds with a digital camera after each days work.....

If I can help in any other way, please let me know.....

 

farfegnubbin

Site Owner
Staff member
Thanks for the update on the mirrors. When something works it’s nice to know where it came from. Yeah, I was wondering what donor could possibly have long, stalked mirrors and also have the correct angle base. But now we know the secret: It had a correct base because you fabricated a nice base. Ha!

Regarding the length of the actuator, what I’ve found is that there’s about an extra inch or so of room in those mounting pockets but, just like you said, there definitely isn’t room for four extra inches.

(Add “That’s what she said” joke here at your own discretion.)

Over the years a handful of builders welded a lever arm onto the parallel arms of their canopy so they could hide an actuator in the side pods of the body. Similarly all Sebrings have linear actuators in the pods that come up through a hole in the body sill rather than the “mounting pocket” of the Sterling. But all of these require perhaps annoyingly difficult modifications, which I know you know. I still just try to stays within the dimensions of those mounting coves (like you were implying, too.)

Lastly, I love the hydraulics until they leak. What a godawful mess when they leak.
 
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