Electric Brakes On Komet Trailer

I don't think disabling trailer brakes is a good idea. There is stability under heavy braking to consider not just retardation. I have twice, separated by about 25 years, had the situation of having to emergency brake on a motorway, the trailer start to swing out (not just sway) and then snap straight as the trailer brake bit fully. My impression was that if the trailer had been unbraked one or both times it would have jackknifed and possibly caused a multiple vehicle incident. Thankfully I will never know for sure but I would never tow a glider trailer any distance without good brakes.

Off the top of my head, if I wanted to disable the surge brake but keep the parking brake, I'd drill a hole thru the tongue assembly for a bolt that would prevent the inner tube from sliding in the outer tube. Then have some rubber inserts to seal the holes if you wanted to remove the bolt to use the surge brake again. You could drill it off center so as not to damage the damper/spring or else drill behind the rear mount for said spring. Or just add a stop of some kind inside the tube to prevent the inner section from compressing under braking loads Early trailers had a lever under the tongue that you could flip up to prevent the tongue from compressing whenever you had to reverse the trailer so that approach might work. I haven't looked at my trailer so there may be a better way. The common thread is that the pparking brake handle actuates the brakes thru the brake rod but independent of the sliding tongue.

Chip Bearden

Drilling through the inner sliding tube is a pretty bad idea IMHO because it weakens the tube and adds an unwanted stress riser. A better solution is to make a two-piece collar that can clamp over the tube between the tongue housing and the hitch, thus preventing it from compressing.

On my trailer, the inner tongue already has horizontal slots in it to allow the tongue to slide. The outer tongue has a hole in it already where the damper strut is anchored. And the bending stress from the inner tongue is transferred into the outer tongue through the sliding bushings so any weakening/stress concentration would be in the outer tongue, and those seem to break where the bending stress is at a max where it enters the trailer. That said, the two-piece collar would work. If you're willing to disable it semi-permanently, a one-piece collar (a piece of tubing) slid over the inner tongue after the coupler is removed (two bolts) and then reattaching the coupler again would work.

All these ideas beg the question of whether it's a good idea to disable the brake system for over-the-road use. There are many trailers out there now without brakes: basically most that don't have an AL-KO system. We drove brakeless trailers for years before the early Libelles starting showing up with Eberle trailers. I've driven my Cobra without brakes a few times. I prefer not to, though, and probably won't disable my brakes even though I pull with a full-size van. But after crawling under the trailer in East Texas in the heat last summer to disconnect the actuator cables (and then reconnect and readjust them when I got home), I might devise a way to disable them quickly to deal with future problems. The problem this summer, however, was that the tongue jammed in the fully compressed position so I had to disconnect the brake actuating cables to free the brakes.

Chip Bearden

On Tuesday, February 19, 2019 at 5:58:47 AM UTC-8, wrote:
Drilling through the inner sliding tube is a pretty bad idea IMHO because it weakens the tube and adds an unwanted stress riser. A better solution is to make a two-piece collar that can clamp over the tube between the tongue housing and the hitch, thus preventing it from compressing.

Yes.
Besides the odd idea of disabling the trailer brakes, drilling holes in the tongue to promote tongue failures we've previously witnessed seems misguided.
It seems to me that failure mostly occurs with a heavily-sprung tow vehicle, long cantilever behind the rear axle, or an overweight trailer tongue. Combinations of those are a gamble.
The max weight rating is on the tongue, most are 100kg.

OP:
One thing I imagine electric brakes would be useful for would be engaging them independently of tow car brakes if there is instability.

Personally find AlKo trailer brakes pretty easy to maintain.
Perhaps change the tongue compression damper more often? If you live where things get rusty, routinely treat the Bowden cables with LPS-3. Grease fittings are there to be used.
Download the trailer manual (Spindelberger have it available, perhaps Anschau)
Jim

Besides the odd idea of disabling the trailer brakes, drilling holes in the tongue to promote tongue failures we've previously witnessed seems misguided.
It seems to me that failure mostly occurs with a heavily-sprung tow vehicle, long cantilever behind the rear axle, or an overweight trailer tongue. Combinations of those are a gamble.

I agree most of the failures I've heard about involve motorhomes. I check for cracks frequently anyway where the tongue enters the trailer (the big stress point), and remove the dolly wheel each time so it doesn't ground.

The hole in the inner tongue shouldn't have any effect unless bending stress is being transferred from inner to outer tube via the slot in the inner tube and the thru bolt/damper mounting. Another hole in the outer tongue could, but there's already a hole there for the rear damping strut mount as well as fittings welded to it (which are stress risers).

As for whether you would WANT to disable the braking system, I don't know. I've done it twice to get to/from contests where there were other brake problems. I don't intend to otherwise but it would be nice to be able to in a hurry if I had to.

One thing I imagine electric brakes would be useful for would be engaging them independently of tow car brakes if there is instability.

Yes, I've never used electric brakes but that capability sounds very nice (and have heard it is from others).

Personally find AlKo trailer brakes pretty easy to maintain.
Perhaps change the tongue compression damper more often?
Keep in mind that this trailer is 27 years ago. My previous Komet was 13 years old when I sold it and had few problems. Such is progress.

I changed the damper strut this summer. Not much different in force or damping than the one I removed.

If you live where things get rusty, routinely treat the Bowden cables with LPS-3. Grease fittings are there to be used.

I grease the fittings in the tongue every year, but those are for the bushings in the outer tongue tube. The cables are more difficult to treat but I plan to do it this spring. Must remove the parking brake cables from the central actuator rod and the backing plates, then spin the cables while pouring/squirting lube into the them.

Download the trailer manual (Spindelberger have it available, perhaps Anschau)

I'm from the old school. I have the paper manual that came with the trailer!

I would love, love, LOVE to hear what I could do to make this system reliable. But each time I've asked for input about a problem, I've gotten different answers. I agree when it's working properly, it's great. Keeping it working properly has been my challenge.

Chip Bearden

Off the top of my head, if I wanted to disable the surge brake but keep the parking brake, I'd drill a hole thru the tongue assembly for a bolt that would prevent the inner tube from sliding in the outer tube. Then have some rubber inserts to seal the holes if you wanted to remove the bolt to use the surge brake again. You could drill it off center so as not to damage the damper/spring or else drill behind the rear mount for said spring. Or just add a stop of some kind inside the tube to prevent the inner section from compressing under braking loads Early trailers had a lever under the tongue that you could flip up to prevent the tongue from compressing whenever you had to reverse the trailer so that approach might work. I haven't looked at my trailer so there may be a better way. The common thread is that the pparking brake handle actuates the brakes thru the brake rod but independent of the sliding tongue.

Chip Bearden

wrote on 2/18/2019 9:58 PM:
I don't think disabling trailer brakes is a good idea. There is stability under heavy braking to consider not just retardation. I have twice, separated by about 25 years, had the situation of having to emergency brake on a motorway, the trailer start to swing out (not just sway) and then snap straight as the trailer brake bit fully. My impression was that if the trailer had been unbraked one or both times it would have jackknifed and possibly caused a multiple vehicle incident. Thankfully I will never know for sure but I would never tow a glider trailer any distance without good brakes.

With a 11,500 tow vehicle and 2500lb trailers, brakes are almost irrelevant for
stopping the combination - I did the experiment on an out and return to Alaska.
And now, the tow vehicle is 13,500lbs - it's even steadier.

Stability is not an issue with the huge difference in weight and the long wheel
base (with four tires on the rear) of the motorhome. Also, I tow 60 mph, pass at
70, and "flutter speed" is well over 100 mph. The trailer has so little affect on
the motorhome, I can't feel what it's doing, not even if a tire blows (done that
experiment).

The best argument for brakes in my situation is dampening the swaying if the
trailer came off the ball, but I believe the chains are strong enough to withstand
the whipping that would ensue, and the motorhome is heavy enough to be easily
controlled during the stop.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

On Tuesday, February 19, 2019 at 7:02:43 PM UTC, Eric Greenwell wrote:
wrote on 2/18/2019 9:58 PM:
I don't think disabling trailer brakes is a good idea. There is stability under heavy braking to consider not just retardation. I have twice, separated by about 25 years, had the situation of having to emergency brake on a motorway, the trailer start to swing out (not just sway) and then snap straight as the trailer brake bit fully. My impression was that if the trailer had been unbraked one or both times it would have jackknifed and possibly caused a multiple vehicle incident. Thankfully I will never know for sure but I would never tow a glider trailer any distance without good brakes..

With a 11,500 tow vehicle and 2500lb trailers, brakes are almost irrelevant for
stopping the combination - I did the experiment on an out and return to Alaska.
And now, the tow vehicle is 13,500lbs - it's even steadier.

Stability is not an issue with the huge difference in weight and the long wheel
base (with four tires on the rear) of the motorhome. Also, I tow 60 mph, pass at
70, and "flutter speed" is well over 100 mph. The trailer has so little affect on
the motorhome, I can't feel what it's doing, not even if a tire blows (done that
experiment).

The best argument for brakes in my situation is dampening the swaying if the
trailer came off the ball, but I believe the chains are strong enough to withstand
the whipping that would ensue, and the motorhome is heavy enough to be easily
controlled during the stop.


Eric I was quite specifically not referring to ordinary trailer swaying instability. I was referring to the driver having to make an emergency stop while towing and the trailer starting to try to overtake the vehicle. The weight of the towing vehicle would be no help there.

wrote on 2/19/2019 12:59 PM:
On Tuesday, February 19, 2019 at 7:02:43 PM UTC, Eric Greenwell wrote:
wrote on 2/18/2019 9:58 PM:
I don't think disabling trailer brakes is a good idea. There is stability under heavy braking to consider not just retardation. I have twice, separated by about 25 years, had the situation of having to emergency brake on a motorway, the trailer start to swing out (not just sway) and then snap straight as the trailer brake bit fully. My impression was that if the trailer had been unbraked one or both times it would have jackknifed and possibly caused a multiple vehicle incident. Thankfully I will never know for sure but I would never tow a glider trailer any distance without good brakes..

With a 11,500 tow vehicle and 2500lb trailers, brakes are almost irrelevant for
stopping the combination - I did the experiment on an out and return to Alaska.
And now, the tow vehicle is 13,500lbs - it's even steadier.

Stability is not an issue with the huge difference in weight and the long wheel
base (with four tires on the rear) of the motorhome. Also, I tow 60 mph, pass at
70, and "flutter speed" is well over 100 mph. The trailer has so little affect on
the motorhome, I can't feel what it's doing, not even if a tire blows (done that
experiment).

The best argument for brakes in my situation is dampening the swaying if the
trailer came off the ball, but I believe the chains are strong enough to withstand
the whipping that would ensue, and the motorhome is heavy enough to be easily
controlled during the stop.


Eric I was quite specifically not referring to ordinary trailer swaying instability. I was referring to the driver having to make an emergency stop while towing and the trailer starting to try to overtake the vehicle. The weight of the towing vehicle would be no help there.

I misunderstood the situation you were describing. That's never happened to me,
even though I've had unbraked trailers from 4 different mfg over 17 years and 75+
thousands of miles around the North America, so I'm not concerned about it.

Also, I don't understand how the trailer could get very much out of line in my
situation: the more it yaws, the trailer tires will be directing back into line,
and the retarding force will be diminishing. The jackknifing I'm familiar with
involves very slippery pavement (ice or lots water - not the situation for 99% of
my towing), or the tow vehicle being pushed out of control (with 9,000 lbs on the
rear axle, it's not likely the 2500lb trailer can do that).

I still think your experience applies to people with lighter tow vehicles, and
they should cautious about disabling the brakes.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf