Electric Trailer Brakes, (Revisited)

Hi All,

By request, I am posting my electric brakes vs surge brakes article/
rambling. It is much the same info as my post on the subject before,
but written more in an article format. It is of course unfinished, but
pretty much covers my thoughts on the subject. My apologies for any
redundant redundant repetitive repetition.
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Most of you probably won't want to hear this, but I will back up
my opinion with some solid logic in the form of a list of 10 good
reasons vs one drawback down below, so if you are sensitive about your
equipment, and do not want to be confused with the facts because your
mind is already made up than read no further. I will start off by
simply saying GET RID OF YOUR SURGE BRAKES, but replace them with
something much better-- ELECTRIC BRAKES. A good brake controller (like
a Tekonsha Prodigy or a Draw-Tite Intella-Stop) is really the key in
this equation, as the controller is in charge of all autonomous brake
functions, and provide the interface to regulate manual operation.
Electric brakes are actually more reliable, require less maintenance,
are much more flexible, and bottom line just plain all around work
better for glider trailers and this is why:
1. They are easier to install (usually even easier to install, as a
new whole system, than it is to fix any of the host of problems that
plaque surge brakes)
2. They are easier to properly maintain- no bleeding/topping off/
corrosive fluids
3. Brakes on trailer can be applied independently of brakes on the
car, in addition to working in unison with the car's brakes, It is
just plain nice to have the option of tapping just the trailer's
brakes when a semi with a 20mph differential speed sets you trailer
wagging :-) -WARNING-more personal opinion coming-For that matter, I
highly recommend against using engine braking on any vehicle under
12,000lbs that has hydraulic brakes on it, in all but extreme
downgrades (over 7%, longer than 5 miles). Brake pads cost $20-$40,
resurfacing drums/rotors adds another $45-$180. A transmission costs
more like $4,000 (installed) and the more yet for a motor. Clutches
are not cheap either for that matter. Just use the brakes on the car,
and very sparingly use the engine and transmission for decelerating,
if ever at all. Reminder-You are NOT a big rig truck, your brakes work
fine and are not prone to overheating so they can be used generously
(especially with brakes on the trailer). Money is better spent on
flying than on easily (yet still safely) minimized mechanical hassles,
not to mention the additional down time...
4. Electric brakes work as they are supposed to while reversing,
meaning they only engage when the car's brakes are applied, as opposed
to engaging during changes in acceleration (again, at least with a
good controller like ones mentioned). You will really notice a
difference the first time you have to really do some serious backing
up. They never accidentally engage, like surges very commonly do while
driving down hills/grades.
5. You keep a breakaway backup battery system in the trailer so the
brakes automatically engage in the unlikely event of a total
separation, stopping the trailers movement and holding it there (20
minutes at max hold is usually the typical minimum requirement for the
breakaway kit's internal battery). Good breakaway kits have a built in
'smart' charger and a charge indicator test light, and charge
automatically while engaged to the tow vehicle. This built in charger
can be tied into your ship's battery so it will also charge it (only
while driving, unless you hook up a solar panel to the line in on the
charger unit, but that's another post...)
6. You can precisely adjust the brakes, WHILE DRIVING, to suit ever
changing road conditions, like mountains, hills, curvy roads, thick
traffic, open road, etc; meaning you can set the voltage they
initially engage at and how quickly they ramp up to full holding power
is adjustable while in motion, and quite easily. (most good elec brake
controllers have this feature, coupled with an digital output voltage
readout)
7. They are a whole lot more reliable after sitting around unused for
a season or two, and then are very easily tested for PROPER function.
I know more than one person that has been in a rear-end accident,
because unknown to them the finicky/easily fouled surge mechanism
froze up or got sticky (Dick Johnson is one of these people, but it
was not his trailer and he was not driving). Do to this phenomenon,
surge brakes get less predictable over time, and are very difficult to
test for proper function and thus keep adjusted. I'm sure there have
been worse accidents due to this, but that is just my intuitive
speculation and have nothing to base that on at this point other than
deductive reasoning.
8. Parts are readily available and thus not need to be ordered form
Germany or wherever, when needed (read expensive, but also very
inconvenient to wait up to 6 weeks for a part, that may not even solve
your problem!).
9. The complete system is relatively inexpensive, my brake system cost
me less than $400 ('smart' shopping that is, but it can be done even
'dumb' shopping for less than $600) including a new axle and a top of
the line controller.
10.Your 'buddies' can't do you the kind favor of accidentally leaving
your E-brake on when they come to get you!

Now The Bad News:
1. Your trailer's brakes only work when YOUR car (or one with an
electric brake controller installed) is towing your trailer. This
seems a small price to pay though, I'd say. Since it is usually
people's personal cars that do any serious hauling of their personal
trailers and people's personal cars are usually the ones left attached
to the trailer with the keys on the floorboard, in spirit of proper XC
preparation. Besides, for most short trips brakes are not of much
necessity (terrain depending of course, but on average...).

I would be more than happy to put together a parts list for
anyone else interested in converting their trailer to electric brakes,
based on the individual trailer. It is quite an easy conversion, and
there are many benefits to this type of system. There are other types
of brake setups yet, like electric driven hydraulic discs and such,
but I have found them to be non ideal (expensive, heavy, over
complicated, unnecessary for the light duty loads, etc) for sailplane
trailers. Me personally, I want to do everything in my power to
protect my sailplane, and electric brakes on my trailer is one more
step towards this goal. Again, this is my just opinion based on
observation and a lot of trailering. I have no ties to the brake
industry, or any others.
Bottom line is that good electric brakes can by far outperform
any surge system, in both immediate short term performance, as well as
long term reliability. It is clearly a superior design, at least for
this particular application, but I do apologize to anyone with surge
brakes that this offends. Lucky for you it is more than likely cheaper
to switch over to a full electric system than to fix problems you will
certainly run into with surges over time.

Paul Hanson

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As a follow up to this "article", I don't think perfectly good surges
should be thrown to the curb. I just don't think much effort should be
made to fix them once you finally realize they are NOT actually
working as they should be (hopefully not due to an unpleasant event).
I would put reason number 3 as the single most important reason,
followed closely by 6 and 7, but none of the reasons are trivial in my
eyes.

Trashcan lid strapped to the back of my pants as I dive for cover,
Paul Hanson

Good information. I have a 1978 Komet in need of a new axle. I have
bee trying to decide between an idler and one with electric brakes.
Either way, I have to do something with the tounge, since it has the
mechanical surge brake and is free to move. Any ideas?

Andrew

On Apr 12, 7:40 am, wrote:
Good information. I have a 1978 Komet in need of a new axle. I have
bee trying to decide between an idler and one with electric brakes.
Either way, I have to do something with the tounge, since it has the
mechanical surge brake and is free to move. Any ideas?

Andrew

I had to replace the axle and tongue on my old 1978 Komet after a
traffic accident and my local shop found a US equivalent with
hydraulic brakes. The retrofit was a lot heavier duty than the
original and worked just fine, but lost the use of the handbrake.

There are plenty of US axles that will fit European trailers - you
just need to decide what features and brakes you'd like.

Mike

sisu1a wrote:

I was hoping someone with surge and electric brake experience would
comment. Since that didn't happen, I'll comment so Paul won't feel ignored.

Electric brakes are actually more reliable, require less maintenance,
are much more flexible, and bottom line just plain all around work
better for glider trailers and this is why:

2. They are easier to properly maintain- no bleeding/topping off/
corrosive fluids

Fluids? The most common factory trailer (Cobra) is all mechanical.

3. Brakes on trailer can be applied independently of brakes on the
car, in addition to working in unison with the car's brakes, It is
just plain nice to have the option of tapping just the trailer's
brakes when a semi with a 20mph differential speed sets you trailer
wagging :-)

If the wagging is a safety concern, I suggest the "fix" is driving
slower until you can modify your equipment to handle upsets without your
intervention. If not, there will be a day when tapping the trailer's
brakes don't work because it's a 30 mph differential, or a strong
thermal, or cross wind catches you coming out from behind a cut in the
road way, or you are distracted and slow on the tapping, or two things
catch you at the same time, or ...

-WARNING-more personal opinion coming-For that matter, I
highly recommend against using engine braking on any vehicle under
12,000lbs that has hydraulic brakes on it, in all but extreme
downgrades (over 7%, longer than 5 miles). Brake pads cost $20-$40,
resurfacing drums/rotors adds another $45-$180. A transmission costs
more like $4,000 (installed) and the more yet for a motor. Clutches
are not cheap either for that matter.

Why do you think engine braking is hard on the engine and transmission?
At least, for automatic transmissions, where you keep it in 3rd instead
of letting it slip into OD/4th gear? None of my vehicles over the last
16 years have cautioned against that. Manual transmissions -- maybe good
advice, if the driver isn't well trained in them.

4. Electric brakes work as they are supposed to while reversing,
meaning they only engage when the car's brakes are applied, as opposed
to engaging during changes in acceleration (again, at least with a
good controller like ones mentioned).

Huh? My surge brakes disengage while I'm backing up, which is how they
are supposed to work. I don't need brakes at 5 mph.

You will really notice a
difference the first time you have to really do some serious backing
up.

What difference would I notice?

They never accidentally engage, like surges very commonly do while
driving down hills/grades.

You mean, while backing down a hill? My surge brakes would never do that
for two reasons: 1) I'm backing up, so they are disengaged 2) the tow
vehicle is not pushing on the tongue, so the brakes can't even be activated.

5. You keep a breakaway backup battery system in the trailer so the
brakes automatically engage in the unlikely event of a total
separation, stopping the trailers movement and holding it there (20
minutes at max hold is usually the typical minimum requirement for the
breakaway kit's internal battery). Good breakaway kits have a built in
'smart' charger and a charge indicator test light, and charge
automatically while engaged to the tow vehicle. This built in charger
can be tied into your ship's battery so it will also charge it (only
while driving, unless you hook up a solar panel to the line in on the
charger unit, but that's another post...)

Tell me again why it's an advantage to keep a battery and charger in the
trailer, instead of none at all, like my surge brake system.

10.Your 'buddies' can't do you the kind favor of accidentally leaving
your E-brake on when they come to get you!

I know I'd REALLY miss the parking brake on my 2400 pound trailer, but I
could get along without it on a 1600 pound trailer.

As a follow up to this "article", I don't think perfectly good surges
should be thrown to the curb. I just don't think much effort should be
made to fix them once you finally realize they are NOT actually
working as they should be (hopefully not due to an unpleasant event).

My Cobra trailer has 130,000+ miles on it, and so far the only real
braking system fix was replacing a drum, and one complete set of brake
shoes. I do put a grease gun to the sliding components on the tongue
every year, and perhaps the frequent use my trailer gets prevents some
problems.

While I'm not persuaded I'd be better off with electric brakes, I still
think Paul makes a strong case for them, and they certainly seem worth
considering.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

On Apr 12, 8:30 pm, Eric Greenwell wrote:
sisu1a wrote:

I was hoping someone with surge and electric brake experience would
comment. Since that didn't happen, I'll comment so Paul won't feel ignored.

Electric brakes are actually more reliable, require less maintenance,
are much more flexible, and bottom line just plain all around work
better for glider trailers and this is why:
2. They are easier to properly maintain- no bleeding/topping off/
corrosive fluids

Fluids? The most common factory trailer (Cobra) is all mechanical.

Fair enough, no fluid. Electrics are still more flexible as well as
more reliable. Why more reliable, well I know for sure that my
electric brakes work. How do I know? I can test them, for ALL
functions and responsiveness, throughout their entire performance
range. As far as I know the only tests for surges are 1. put on the e-
brake, does it roll? 2. Get trailer/tow vehicle up to speed. Give a
firm application to the brakes. Did you feel the trailer first push
into the vehicle before pulling on the hitch? (that's got to be good
for the car) I suppose thats all there is you can test them for, since
they are a binary system. on or off.


3. Brakes on trailer can be applied independently of brakes on the
car, in addition to working in unison with the car's brakes, It is
just plain nice to have the option of tapping just the trailer's
brakes when a semi with a 20mph differential speed sets you trailer
wagging :-)

If the wagging is a safety concern, I suggest the "fix" is driving
slower until you can modify your equipment to handle upsets without your
intervention. If not, there will be a day when tapping the trailer's
brakes don't work because it's a 30 mph differential, or a strong
thermal, or cross wind catches you coming out from behind a cut in the
road way, or you are distracted and slow on the tapping, or two things
catch you at the same time, or ...

Wagging is not one of the concerns I put the electric brakes on to
fix, that was an unintended benefit that it conveniently helps with
(the 7 point buck staring at me in the middle of my lane while driving
around a 55mph blind corner on a mountain highway in Wyoming was my
actual inspiration). It is especially nice though, when I am teaching
someone else to drive my trailer. For me, I have found that correctly
steering with the pressure change of the 'bow wake' of trucks etc,
(using resistance to damp out the movement before it even sets up an
oscillation) to be much more effective, but I can't seem to teach this
technique to anyone else, so I like that they can 'tap' the brakes
until they figure out the finer finesse of sailplane trailering (if
they ever figure it out). Electric brakes ALSO work automatically too
of course, according to the level you set them to (which to reiterate
can be easily adjusted WHILE driving). The manual override is what you
would "tap" (actually it is a throttle lever, and again you have a
voltage readout so you can tell, besides feel alone, how much braking
you are giving it). If one was too unaware to use normal braking, then
perhaps they should not be driving at all. I am focusing on hardware,
because it is easier to share the findings. I fail to see how a
thermal will affect me while driving, and your other points actually
support the case for electrics, since they not only automatically work
but can be tuned to current needs, as well as to be used manually.

-WARNING-more personal opinion coming-For that matter, I
highly recommend against using engine braking on any vehicle under
12,000lbs that has hydraulic brakes on it, in all but extreme
downgrades (over 7%, longer than 5 miles). Brake pads cost $20-$40,
resurfacing drums/rotors adds another $45-$180. A transmission costs
more like $4,000 (installed) and the more yet for a motor. Clutches
are not cheap either for that matter.

Why do you think engine braking is hard on the engine and transmission?
At least, for automatic transmissions, where you keep it in 3rd instead
of letting it slip into OD/4th gear? None of my vehicles over the last
16 years have cautioned against that. Manual transmissions -- maybe good
advice, if the driver isn't well trained in them.

Because you are putting load on it, load that is frankly quite
avoidable. Load = wear, period. I choose to put the load/wear my
brakes as opposed to major drive train components. The loading of most
braking is WELL within the safe tolerances of these systems. I do not
do this at the expense of safety, nor do I suggest anyone else to.
Drive however makes you comfortable and keeps you in 'the zone'
please, as I have to share the road with you and I don't want anyone
feeling out of their element. I do recommend that people experiment a
little with their vehicles and driving styles from time to time with
regards to braking and gearing. It is a good thing to to do as an
academic exercise if nothing else, as there are always things that can
be learned (again, safety first!). Naturally the car manufacture is
NOT going to caution you against ruining expensive parts they are more
than happy to sell you.


4. Electric brakes work as they are supposed to while reversing,
meaning they only engage when the car's brakes are applied, as opposed
to engaging during changes in acceleration (again, at least with a
good controller like ones mentioned).

Huh? My surge brakes disengage while I'm backing up, which is how they
are supposed to work. I don't need brakes at 5 mph.


I'm glad that Cobra actually provides some decent hardware on their
$20,000 trailers. I feel safe to say that most of the surges out there
do NOT have the free-backing mechanism or a reverse solenoid hooked
into the tow vehicles wiring. While I agree that you may not need
brakes at 5mph, I can imagine cases where they might be nice to have,
albeit rare.

You will really notice a
difference the first time you have to really do some serious backing
up.

What difference would I notice?

Well YOU would not notice much seeing as you have the disengage
mechanism, but most folks with classic substandard surge getups sure
would!

They never accidentally engage, like surges very commonly do while
driving down hills/grades.

You mean, while backing down a hill? My surge brakes would never do that
for two reasons: 1) I'm backing up, so they are disengaged 2) the tow
vehicle is not pushing on the tongue, so the brakes can't even be activated.

No, I do not mean while backing down a hill. I mean when your trailer
is trying to overrun the tow vehicle while you are driving down a
steep enough hill and you had no idea your brakes were engaged for an
entire down grade-until you got to the bottom and smelled it-or a
wheel fell off etc. It was this very phenomenon that initiated my
original post on the subject some time back.

5. You keep a breakaway backup battery system in the trailer so the
brakes automatically engage in the unlikely event of a total
separation, stopping the trailers movement and holding it there (20
minutes at max hold is usually the typical minimum requirement for the
breakaway kit's internal battery). Good breakaway kits have a built in
'smart' charger and a charge indicator test light, and charge
automatically while engaged to the tow vehicle. This built in charger
can be tied into your ship's battery so it will also charge it (only
while driving, unless you hook up a solar panel to the line in on the
charger unit, but that's another post...)

Tell me again why it's an advantage to keep a battery and charger in the
trailer, instead of none at all, like my surge brake system.


Because then you have a battery/charger in your vehicle. It is nice to
have emergency 12v power when and if it were needed. A lot of things
could be powered off that battery in a pinch. Best of all, you can
splice into the charging circuit and use it to keep your plane's
batteries topped off if you hook solar panels up to it. Hmmm, now that
I think back, weren't YOU looking for a solution to keep your solar
panels from frying batteries a little while back?

10.Your 'buddies' can't do you the kind favor of accidentally leaving
your E-brake on when they come to get you!

I know I'd REALLY miss the parking brake on my 2400 pound trailer, but I
could get along without it on a 1600 pound trailer.

With electric brakes you have a battery/charger in the trailer (sound
familiar?). This is intended as an emergency breakaway backup and has
a pull switch on the tongue. Although it is not intended as an e-
brake, that is essentially what it is. If you ever needed to use the e-
brake to man-handle the trailer, it is actually quite easy, but the
manufacture does recommend against using it in perilous situations.
There is also the drawback that you have limited time with this action
(Federal minimum for battery is 15 minutes of full locked brakes), but
that seems like it should do just fine for any grunt work you may need
to accomplish, particularly if you have chocks too.

As a follow up to this "article", I don't think perfectly good surges

should be thrown to the curb. I just don't think much effort should be
made to fix them once you finally realize they are NOT actually
working as they should be (hopefully not due to an unpleasant event).

My Cobra trailer has 130,000+ miles on it, and so far the only real
braking system fix was replacing a drum, and one complete set of brake
shoes. I do put a grease gun to the sliding components on the tongue
every year, and perhaps the frequent use my trailer gets prevents some
problems.

That is undeniably a lot of miles. Your opinion is indeed valid for
your trailer, and your logic can not be argued with as it applies to
your case. Brake shoes are expected to wear, and replacing a single
drum is not a big deal. Greasing the sliding components is a very good
practice, that is followed by everyone would probably spare a lot of
heartache in the end. I think you hit the nail on the head about your
frequent use theory as well. I also suspect that Cobra may actually
use decent parts, which is commendable. Clearly this is not the case
with ALL trailer manufacturers however, and THIS is where the electric
conversion really should come into play. It should be noted though,
that although Cobra's surge system has good maintenance reliability
(recent crops anyhow), that does not circumvent the fact that electric
brakes can outperform surges-as far as the action of braking is
concerned- in both stopping power and most certainly in finesse. There
is a reason electrics are the most common type of brakes in horse
trailers; they can be used smoothly but firmly if needed, but with an
amazing degree of control and usable adjustment range.

While I'm not persuaded I'd be better off with electric brakes, I still
think Paul makes a strong case for them, and they certainly seem worth
considering.

To reiterate, I'm not trying to persuade anyone with a functional
getup -that they are happy with- to become a 'convert'. But do be open
to other options when and if the time comes where you find yourself
considering paying $300 or more to fix broken surges. At that price
level, you are getting close to having a complete electric setup, and
may be happier with the electrics. Now I'm sure someone else will
just pull the pin out and throw it back again, sigh...

No longer feeling ignored,
Paul Hanson

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes"http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org

sisu1a wrote:
Electrics are still more flexible as well as
more reliable. Why more reliable, well I know for sure that my
electric brakes work. How do I know? I can test them, for ALL
functions and responsiveness, throughout their entire performance
range. As far as I know the only tests for surges are 1. put on the e-
brake, does it roll? 2. Get trailer/tow vehicle up to speed. Give a
firm application to the brakes. Did you feel the trailer first push
into the vehicle before pulling on the hitch?

My Cobra acts differently:
* mild brake application - we just slow down
* more brake application - a little bump as the surge brake begins
braking the trailer
* me, the car, and trailer begin slowing down more quickly, but there is
no evidence the trailer is *pulling* on the car - it's just not pushing
as hard.

(that's got to be good
for the car) I suppose thats all there is you can test them for, since
they are a binary system. on or off.

Not on the Cobra trailer, which has "proportional" brakes - the harder
you brake, the more the force is applied to the trailer tongue, which
applies more force to the brake shoes, which adds more retarding force
to the trailer. It is definitely not an ON/OFF system.

Electric brakes ALSO work automatically too
of course, according to the level you set them to (which to reiterate
can be easily adjusted WHILE driving).

Why would I want to adjust the brakes? Why aren't they set correctly
from the start? I've never felt the need to adjust the brakes on my Cobra.

I fail to see how a
thermal will affect me while driving,

A strong thermal can be very upsetting, because the winds are going in a
small circle that don't affect the tow vehicle and the trailer in the
same direction at the same time. Strong thermals can make my 11,000
pound motorhome towing my 2400 pound trailer deviate as much as a 20+
knot cross wind when coming out from behind a "cut" in a hill, and they
aren't as predictable. I don't drive over 60 mph except for passing, and
I can assure you the combination is dead stable at 90 mph, so it's not
like I'm close to the safe limit.

Perhaps the effect is very vehicle dependent.

Why do you think engine braking is hard on the engine and transmission?

Because you are putting load on it, load that is frankly quite
avoidable. Load = wear, period.

Well, yes, but it's a pretty light load, I think. It's just the pistons
sucking against a closed throttle during the intake stroke, and only the
tiniest power pulse (if any) on the power stroke, so the load is far,
far less than when the rig went up the hill with a lot of throttle, just
minutes before. If you want to reduce wear, slowing down slightly on the
upside is going to make a much bigger difference than using engine
braking on the down side.

I choose to put the load/wear my
brakes as opposed to major drive train components. The loading of most
braking is WELL within the safe tolerances of these systems.

I don't think it's a bad plan, and if your brakes can handle it, it's a
reasonable choice. What can happen is the brakes overheat before the
driver has enough warning to do something about it. I prefer to risk the
extra net wear on the vehicle than to experiment with the limits of
the braking system.

Besides, I have no reason to believe pressing the "OD" button to lock
out 4th gear on my motorhome, Camry, or mini-van causes them significant
wear when going down a hill; in fact, the newer models of these vehicles
(last 3 or 4 years) will automatically do that for you while on speed
control.

Naturally the car manufacture is
NOT going to caution you against ruining expensive parts they are more
than happy to sell you.

Except for that pesky warranty... Basically, I agree with you: short
hills, brakes are fine; long hills, down shift and use the brakes
sparingly. Don't "ride" the brakes, is what I was taught, and I think
it's still good advice.

While I agree that you may not need
brakes at 5mph, I can imagine cases where they might be nice to have,
albeit rare.

So rare, that after 200,000+ miles of towing glider trailers, I still
can't think of a single situation.

No, I do not mean while backing down a hill. I mean when your trailer
is trying to overrun the tow vehicle while you are driving down a
steep enough hill and you had no idea your brakes were engaged for an
entire down grade-until you got to the bottom and smelled it-or a
wheel fell off etc. It was this very phenomenon that initiated my
original post on the subject some time back.

I've never noticed that. It might be because the Cobra trailer has a
pressurized shock absorber in the surge mechanism that prevents the
brake from applying unless there is significant force on the tongue.
This means it takes more than a gentle stop to overcome the pressure in
the shock absorber before the brakes will apply, and likely prevents the
brakes from applying when going downhill, unless it's quite steep.

Tell me again why it's an advantage to keep a battery and charger in the
trailer, instead of none at all, like my surge brake system.


Because then you have a battery/charger in your vehicle. It is nice to
have emergency 12v power when and if it were needed. A lot of things
could be powered off that battery in a pinch.

How big is this battery? Can't the tow vehicles battery be used to power
stuff in a pinch?

Best of all, you can
splice into the charging circuit and use it to keep your plane's
batteries topped off if you hook solar panels up to it.

You don't need a battery in the trailer to do that - just hook up a
solar panel and regulator that connects to the glider battery. To
reliably charge the glider in time for the next day will take a much
larger panel than one suitable for keeping a breakaway battery charged
up, so I don't see a savings there.

Hmmm, now that
I think back, weren't YOU looking for a solution to keep your solar
panels from frying batteries a little while back?

Yes, and the problem I had (improper regulator) would have fried the
battery the trailer depends on for it's breakaway duties.

I know I'd REALLY miss the parking brake on my 2400 pound trailer, but I
could get along without it on a 1600 pound trailer.

With electric brakes you have a battery/charger in the trailer (sound
familiar?). This is intended as an emergency breakaway backup and has
a pull switch on the tongue. Although it is not intended as an e-
brake, that is essentially what it is. If you ever needed to use the e-
brake to man-handle the trailer, it is actually quite easy, but the
manufacture does recommend against using it in perilous situations.
There is also the drawback that you have limited time with this action
(Federal minimum for battery is 15 minutes of full locked brakes), but
that seems like it should do just fine for any grunt work you may need
to accomplish, particularly if you have chocks too.

That might work. The situations I had in mind would likely take only
5-10 minutes to resolve (and the brake wouldn't need to be applied all
that time,either), and then the trailer would be hooked up again or the
chocks would be in place.

that does not circumvent the fact that electric
brakes can outperform surges-as far as the action of braking is
concerned- in both stopping power and most certainly in finesse. There
is a reason electrics are the most common type of brakes in horse
trailers; they can be used smoothly but firmly if needed, but with an
amazing degree of control and usable adjustment range.

Is the reason the electric brakes need all this adjustment (in horse
trailers, for example) is to compensate for the large differences in
braking action required between a loaded and unloaded trailer? A surge
brake system automatically compensates for load variations, an ideal
situation in a trailer that might be 1700 pounds loaded and 1000 pounds
when the glider is out of it.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Not on the Cobra trailer, which has "proportional" brakes - the harder
you brake, the more the force is applied to the trailer tongue, which
applies more force to the brake shoes, which adds more retarding force
to the trailer. It is definitely not an ON/OFF system.

OK, so they're proportional. But besides jamming your brakes at all
kinds of speeds, how can you test them for function through the entire
range, or do you just have to assume they will work throughout their
entire range based on their lower level performances (lower level
being easily verified without risking damage to trailer's contents by
simply braking)


Why would I want to adjust the brakes? Why aren't they set correctly
from the start? I've never felt the need to adjust the brakes on my Cobra.

Because much like the air, conditions can change very rapidly on the
road. When I have the road to myself, and it is relatively flat I set
the auto engaging mechanism rather low. I prefer the lowest setting I
feel good about at any given time, as I like to drive efficiently, and
do not normally want the trailer's brakes 'leading' the car, thus
keeping the feel of the combo very natural. But when the road gets a
little more crowded, or I see people are starting to drive more
chaotically, I prefer to increase my stopping capacity, sometimes
significantly, to the point where the trailer is most certainly
pulling on the hitch (but it does not jerk it since the ramp up is
electronically regulated), and I can stop the combo in a shorter
distance than I can the van alone when set aggressively. Of course
they have a progression too (gyroscopically augmented pendulum
regulated), and the elec brake's adjustment range is actually just
setting the initial engaging voltage, thus flattening or steepening
the progression to the full 12v. I also like the brakes to be much
more reactive when driving mountainous/curvy areas. No matter what
setting the automatic engaging mechanism is set to, I of course still
have the manual override and again the whole jobbie has a digital
voltage readout that makes for a very user friendly interface, but can
be set and ignored too if you want.

I fail to see how a
thermal will affect me while driving,

A strong thermal can be very upsetting, because the winds are going in a
small circle that don't affect the tow vehicle and the trailer in the
same direction at the same time. Strong thermals can make my 11,000
pound motorhome towing my 2400 pound trailer deviate as much as a 20+
knot cross wind when coming out from behind a "cut" in a hill, and they
aren't as predictable. I don't drive over 60 mph except for passing, and
I can assure you the combination is dead stable at 90 mph, so it's not
like I'm close to the safe limit.

The real question is, how did you resist pulling over, assembling and
launching?

About driving 60: Although it may leave you with less energy in the
equation to manage, I feel like driving much below the speed limit
(like doing 60 in an 80 for instance) is far more dangerous to
yourself and the other drivers on the road, since you then make
yourself an obstacle that needs deviated around. With every car that
passes you, your odds of being hit by one of them increases. By
driving the same speed as the cars around you, you are much less
likely to be hit by one of them. Sometimes I slow down a bit too, but
usually only to get a different set of drivers around me because I've
had it with the knuckelheads around me. I am not worried about ME
crashing, I am indeed worried about one of 'them' hitting me though.
Most folks do not put much thought into driving, and it is usually
demonstrated for me every time I drive.

Perhaps the effect is very vehicle dependent.

Aerodynamics are indeed fickle.

Why do you think engine braking is hard on the engine and transmission?

Because you are putting load on it, load that is frankly quite
avoidable. Load = wear, period.

Well, yes, but it's a pretty light load, I think. It's just the pistons
sucking against a closed throttle during the intake stroke, and only the
tiniest power pulse (if any) on the power stroke, so the load is far,
far less than when the rig went up the hill with a lot of throttle, just
minutes before. If you want to reduce wear, slowing down slightly on the
upside is going to make a much bigger difference than using engine
braking on the down side.

Wear is wear, and it is cumulative. If even light wear (which I don't
believe this actually is) can be avoided, it should be avoided, but I
buy your wear theory about slowing for hills though. I used to use
cruise control (constant speed), but I have dramatically increased
fuel economy (which indicates less wear of course) by manually driving
constant RPM (which made me slow for climbs, but speed up for
descents) instead. I wish my vehicle had an option to use either
method.

I choose to put the load/wear my
brakes as opposed to major drive train components. The loading of most
braking is WELL within the safe tolerances of these systems.

I don't think it's a bad plan, and if your brakes can handle it, it's a
reasonable choice. What can happen is the brakes overheat before the
driver has enough warning to do something about it. I prefer to risk the
extra net wear on the vehicle than to experiment with the limits of
the braking system.


I've already experimented with several brake systems, and can't afford
new cars. I have experienced brake fade while driving a large buses
that had an automatic with no engine brake. It is not a sudden
situation with little warning, you can feel effectiveness diminishing
slowly and can take steps (assuming you haven't run yourself out of
options). It really made me appreciate hydraulic brake systems since
the stopping capacity is several magnitudes higher as a percentage
ratio. I have faith in my cars/van's brakes. Of course I don't ride
the brakes either, and if shaving the speed off in smooth but
strategic bites is becoming ineffective, I do indeed use the lower
gear. It's just that I have driven with lots of goofy drivers (some of
them pilots even) and have seen a lot of bad habits people use that
most of the time do not increase safety but usually greatly increase
wear. I even try to park vehicles so that I will not need to use
reverse to get out (towing or not), as the car will simply only go
into reverse x amount of times, so I try not to waste them. I do not
go very far out of my way to do this, but this mentality when added up
does extend the life of vehicles etc.


Naturally the car manufacture is NOT going to caution you against ruining expensive parts they are more
than happy to sell you.

Except for that pesky warranty... Basically, I agree with you: short
hills, brakes are fine; long hills, down shift and use the brakes
sparingly. Don't "ride" the brakes, is what I was taught, and I think
it's still good advice.

Warranties don't last forever, and quite often vehicles suffer
catastrophic failures of major components shortly after coming out of
warranty. I have seen very little from car manufacturers do dispel my
belief in the science of planned obsolescence.
http://en.wikipedia.org/wiki/Planned_obsolescence . I choose to use
the brakes generously and use the engine/transmission sparingly, and
again of course don't 'ride my brakes'.


No, I do not mean while backing down a hill. I mean when your trailer
is trying to overrun the tow vehicle while you are driving down a
steep enough hill and you had no idea your brakes were engaged for an
entire down grade-until you got to the bottom and smelled it-or a
wheel fell off etc. It was this very phenomenon that initiated my
original post on the subject some time back.

I've never noticed that. It might be because the Cobra trailer has a
pressurized shock absorber in the surge mechanism that prevents the
brake from applying unless there is significant force on the tongue.
This means it takes more than a gentle stop to overcome the pressure in
the shock absorber before the brakes will apply, and likely prevents the
brakes from applying when going downhill, unless it's quite steep.

You mean you've never noticed it with YOUR Cobra. Others have already
posted about this problem here, as well as a host of other surge/
tongue related issues that you would NEVER have with electrics. I have
never heard of anyone with electric brakes on their trailer having the
wheels fall off due to a brake related mishap either for that matter.

Tell me again why it's an advantage to keep a battery and charger in the
trailer, instead of none at all, like my surge brake system.

Because then you have a battery/charger in your vehicle. It is nice to
have emergency 12v power when and if it were needed. A lot of things
could be powered off that battery in a pinch.

How big is this battery? Can't the tow vehicles battery be used to power
stuff in a pinch?

I think 7ah, but I'm not sure. Sure you can use the tow vehicles
battery, assuming it is not dead or that the tow vehicle is even
anywhere nearby. How about for running lights in/on your trailer for
another example of the usefulness of a battery/charger in the trailer,
regardless of what brakes you have!

Best of all, you can
splice into the charging circuit and use it to keep your plane's
batteries topped off if you hook solar panels up to it.

You don't need a battery in the trailer to do that - just hook up a
solar panel and regulator that connects to the glider battery. To
reliably charge the glider in time for the next day will take a much
larger panel than one suitable for keeping a breakaway battery charged
up, so I don't see a savings there.

I don't propose this as a substitute for a real charger, so I don't
see how it would save money either (except indirectly perhaps if you
did happen to switch to electric brakes rather than fixing expensive
surges). If I fitted a panel to the trailer for it's brakes though, of
course it would be hearty enough to handle the glider's battery as
well.

Hmmm, now that
I think back, weren't YOU looking for a solution to keep your solar
panels from frying batteries a little while back?

Yes, and the problem I had (improper regulator) would have fried the
battery the trailer depends on for it's breakaway duties.

OK

that does not circumvent the fact that electric
brakes can outperform surges-as far as the action of braking is
concerned- in both stopping power and most certainly in finesse. There
is a reason electrics are the most common type of brakes in horse
trailers; they can be used smoothly but firmly if needed, but with an
amazing degree of control and usable adjustment range.

Is the reason the electric brakes need all this adjustment (in horse
trailers, for example) is to compensate for the large differences in
braking action required between a loaded and unloaded trailer? A surge
brake system automatically compensates for load variations, an ideal
situation in a trailer that might be 1700 pounds loaded and 1000 pounds
when the glider is out of it.

Electric brakes don't "need all this adjustment" as you put it (of
course they need the occasional pad adjustment, like any drum brake),
it is just that you have the OPTION to do so should you choose, and I
am a big fan of choices. The calibration range is simply a matter of
built in flexibility, to make the trailer adjustable to your taste
(which of course can continually change and still be accommodated for)
rather than the other way around. Electric brakes would be on lots
more vehicles were it not for the fact the boat industry adopted them
before there were good solutions for making the crucial electrical
components resilient to water, and boat brakes get dunked. This caused
a premature public opinion to form, which the surge brake moguls have
been more than happy to exploit. Another black eye for electrics has
been a lack of good controllers, none of which are a problem anymore.
These things are excellent, and I recommend putting some miles on a
good setup with them before you make your final judgement on them. For
me it is difficult to find the redeeming qualities of surges (and I am
trying), while the benefits of electrics are quite abundant.

Is there even one thing that surges can do that electrics can't do
better? (besides putting your wallet on a diet)

Sir Paul of Oakland,
Defender of Electric Brakes,
Flyer of Sailplanes,
Eater of Tacos

Wear is wear, and it is cumulative. If even light wear (which I don't
believe this actually is) can be avoided, it should be avoided, but I
buy your wear theory about slowing for hills though. I used to use
cruise control (constant speed), but I have dramatically increased
fuel economy (which indicates less wear of course) by manually
driving
constant RPM (which made me slow for climbs, but speed up for
descents) instead. I wish my vehicle had an option to use either
method.

**************************

The way I learned it that is Heat = Wear. The wear on the brakes is
obvious as this is a friction system that directly wears on the
components.
When engine braking most of the energy is used to compress (heat) the
air in the cylinders of the engine. The engine has a very good cooling
system to deal with this. Wear on the drive train should be mininmal
as in a properly designed drive train the is no metal to metal contact
as there should be a thin film of oil between all the metal/metal
contact surfaces.
Hydraulic drive trains like the Torque converter in automaic
transmissions can heat the oil which can damage tranmission parts if
it gets too hot. So I do tend to avoid much engine braking with many
automatic transmissions.

Brian.

On Apr 14, 6:31*am, Brian wrote:
Wear is wear, and it is cumulative. If even light wear (which I don't

believe this actually is) can be avoided, it should be avoided, but I
buy your wear theory about slowing for hills though. I used to use
cruise control (constant speed), but I have dramatically increased
fuel economy (which indicates less wear of course) by manually
driving
constant RPM (which made me slow for climbs, but speed up for
descents) instead. I wish my vehicle had an option to use either
method.

**************************

The way I learned it that *is Heat = Wear. *The wear on the brakes is
obvious as this is a friction system that directly wears on the
components.
When engine braking most of the energy is used to compress (heat) the
air in the cylinders of the engine. The engine has a very good cooling
system to deal with this. Wear on the drive train should be mininmal
as in a properly designed drive train the is no metal to metal contact
as there should be a thin film of oil between all the metal/metal
contact surfaces.
Hydraulic drive trains like the Torque converter in automaic
transmissions can heat the oil which can damage tranmission parts if
it gets too hot. So I do tend to avoid much engine braking with many
automatic transmissions.

Brian.

WOW! Huge thanks to Paul and Eric. BOTH sides of the Electric / Surge
are nicely presented.
I personnaly think that a properly working SURGE brake is better all
around for BRAKING PERFORMANCE since the braking force applied is
mechnically controlled by the force required. No adjusting for an
empty trailer required.
However, in my case, my 30 year old Komet was not maintained
particulary well by some of the previous owners so the tongue is
suspect, AND the rubber band torsion suspension is sacked. On my very
limited budget, the Dexter axle with electric brakes wins out. I will
use a battery for the trailer that also fits my glider, and keep it
topped up with a small solar panel.

sisu1a wrote:

OK, so they're proportional. But besides jamming your brakes at all
kinds of speeds, how can you test them for function through the entire
range, or do you just have to assume they will work throughout their
entire range based on their lower level performances (lower level
being easily verified without risking damage to trailer's contents by
simply braking)

On the Cobra, it's a very simple mechanical system: pushing on the
coupler (what the tow vehicle does when it brakes) makes the sliding
element pull the cables (via a long rod) going to the brake shoes. So,
brake harder, more pull, more braking.

You can check the basic operation by applying the parking brake, which
exercises the entire system except for the sliding coupler component. If
the parking brake works, and the lever position is within
specifications, you know the adjustments are correct.

You then check the coupler/slider action by braking with the trailer
attached. If there is braking action (you can feel it), you know the
entire system is functional.

Why would I want to adjust the brakes? Why aren't they set correctly
from the start? I've never felt the need to adjust the brakes on my Cobra.

Because much like the air, conditions can change very rapidly on the
road. When I have the road to myself, and it is relatively flat I set
the auto engaging mechanism rather low. I prefer ...

snipped - long list of nuanced preferences. I still don't want to do any
of those things, despite being an obsessive, detail oriented person, as
their value seems marginal at best, and introduces the opportunity to
have things set wrong. Most pilots and their crew would better off
without that opportunity, I believe.

About driving 60: Although it may leave you with less energy in the
equation to manage, I feel like driving much below the speed limit
(like doing 60 in an 80 for instance) is far more dangerous to
yourself and the other drivers on the road, since you then make
yourself an obstacle that needs deviated around. With every car that
passes you, your odds of being hit by one of them increases. By
driving the same speed as the cars around you, you are much less
likely to be hit by one of them. Sometimes I slow down a bit too, but
usually only to get a different set of drivers around me because I've
had it with the knuckelheads around me. I am not worried about ME
crashing, I am indeed worried about one of 'them' hitting me though.
Most folks do not put much thought into driving, and it is usually
demonstrated for me every time I drive.

The above is not related to brakes; however, the choice of driving speed
is much more important to safety than the kind brakes your trailer has.
It should at least be slow enough that your trailer remains stable under
the conditions; that you can stop fast enough to avoid obstacles (cars
slowing, deer, whatever); that your tires are well within their ratings
(both vehicles); and that you can still manage a safe stop if a tire blows.

At 60 mph on an Interstate (most of my trailering) seems just as safe as
75, because passing is easy. Two lane roads, regardless of the speed
limit, is where the danger is. Most of that danger occurs when I have to
drive *less* than 60 mph, due to traffic, hills, and curves. Since it's
not related to brakes, I'll leave the issue for another thread.

I used to use
cruise control (constant speed), but I have dramatically increased
fuel economy (which indicates less wear of course) by manually driving
constant RPM (which made me slow for climbs, but speed up for
descents) instead. I wish my vehicle had an option to use either
method.

The above definitely applies to my motorhome, and I also wish for the
option!

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org