New product: Ultimate Servo Bracket
09-04-2014, 10:05 AM
#26
Thread Starter
Hi Oli,
Now that you have tun this test, how do you feel about the practice of adhering a bracket like this to a servo cover and then bolting the cover to the structure? How does the tensile strength of the screw mounting compare to the strength of this bracket/adhesive/cover?
Now that you have tun this test, how do you feel about the practice of adhering a bracket like this to a servo cover and then bolting the cover to the structure? How does the tensile strength of the screw mounting compare to the strength of this bracket/adhesive/cover?
I will do a test with a A-10 cover to see how many countersink screws need to be put in place to hold that mighty load.
Anyway, all of this is not about holding a static load, but taking a flutter condition. Peak load during flutter can reach such values on big models. It is also about servo mounting rigidity and precision. These brackets are certainly not sub-par on that matter.
BTW all of this is applicable ONLY if the gluing area has been prepped correctly ( i.e. the 10 small dots and a dust free rough surface. The Mibo covers come with a peel ply surface
).I will make a USB user manual with all these considerations and the table showing shear strength for certain types of glue.
09-05-2014, 01:48 PM
#28
Thread Starter
09-07-2014, 04:54 PM
#30
Thread Starter
My servo covers were prepped with peel-ply. The carbon fiber surface should feel very rough, with lots of spikes. If this is not the case for you, please roughen the fabric with a rotary toll before gluing. Also don't forget the 10 small dots to increase the shear strength...
09-14-2014, 08:03 AM
#32
My Feedback: (15)
I received my servo mounts from Oli this week. As usual, they were sent quickly and arrived nicely packaged.
For the A10, there is plenty of room for them. Considering my last A10 had the black plastic mounts from Tam, I suspect this will be a clear upgrade, although I had zero trouble with the black plastic/Tam mounts either.
Oli, thanks for getting all of this to me and for making the whole process simple and expeditious.
Dave
For the A10, there is plenty of room for them. Considering my last A10 had the black plastic mounts from Tam, I suspect this will be a clear upgrade, although I had zero trouble with the black plastic/Tam mounts either.
Oli, thanks for getting all of this to me and for making the whole process simple and expeditious.
Dave
09-15-2014, 01:20 AM
#33
Thread Starter
I received my servo mounts from Oli this week. As usual, they were sent quickly and arrived nicely packaged.
For the A10, there is plenty of room for them. Considering my last A10 had the black plastic mounts from Tam, I suspect this will be a clear upgrade, although I had zero trouble with the black plastic/Tam mounts either.
Oli, thanks for getting all of this to me and for making the whole process simple and expeditious.
Dave
For the A10, there is plenty of room for them. Considering my last A10 had the black plastic mounts from Tam, I suspect this will be a clear upgrade, although I had zero trouble with the black plastic/Tam mounts either.
Oli, thanks for getting all of this to me and for making the whole process simple and expeditious.
Dave
The differences between the USB PYCABS mounts and other products available on the market are:
.The contact surface with the servo is maximum and up to 3 times larger than other products. This will give you the minimum servo casing deflection and maximum torque transfer capability. Flight control precision, responsiveness, return to center and flutter tolerance are maximized.
.The mounting screws and washers are at least 2 times bigger than any other system. The servo is fastened at maximum mounting tabs torque ( if done as per the user manual ) and will not move. Flutter tolerance is once again optimized.
. The internal PYCABS honeycomb structure givse a resistance-to-weight ratio that is unrivaled so far. The glue compatibility and open honeycomb structure offer a glue joint resistance of over 200 lbs. The material itself has a tensile strength 4000 PSI. The bracket itself would brake at 2000 lbs. Once again this offers unrivaled performance in case of flutter. Of course, as always, flutter will stress all the aircraft structure and it will brake at the weakest link. Which will not be the servo bracket!
You will notice the difference on very fast and precise jets. Not sure about the A-10 but I'd be interested to get your feedback on this.
12-05-2014, 03:24 AM
#34
Thread Starter
I have reached the limit of the USB resistance on the gluing interface. 285 lbs per servo with Hysol 9462. That is a mighty 1700 oz.in of torque.
http://www.rcuniverse.com/forum/rc-j...ve-test-4.html
This is far exceeding the best professional servo, however it will ensure that the bracket stays secure in the structure in case of flutter.
The weak point will most probably be the structure itself in that case.
I have updated the USB user manual as well.
http://www.geohei.lu/olin/data/model...%20rev%202.pdf
The product page is here:
http://www.ultimate-jets.net/product...-servo-bracket
http://www.rcuniverse.com/forum/rc-j...ve-test-4.html
This is far exceeding the best professional servo, however it will ensure that the bracket stays secure in the structure in case of flutter.
The weak point will most probably be the structure itself in that case.
I have updated the USB user manual as well.
http://www.geohei.lu/olin/data/model...%20rev%202.pdf
The product page is here:
http://www.ultimate-jets.net/product...-servo-bracket
12-05-2014, 03:54 AM
#35
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I've used the new servo brackets in two different jet installs so far. My observations: 1. Quick and easy assembly onto the servo.
2. Light in weight.
3. Very strong and rigid when assembled.
4. Easy to remove servo from bracket once installed.
5. Once glued into place, it's not coming off.
These are now my "go to" favorite servo brackets in the shop.
Cheers,
Joe Grice
2. Light in weight.
3. Very strong and rigid when assembled.
4. Easy to remove servo from bracket once installed.
5. Once glued into place, it's not coming off.
These are now my "go to" favorite servo brackets in the shop.
Cheers,
Joe Grice
12-05-2014, 07:36 AM
#37
I am probably not looking at this bracket correctly but do the mounting screws face up towards the wing skin or towards the leading edge ?? I cant understand how you get the screws out after the bracket is glued in. Other servo brackets have some sort of cap that holds the servo in the slot and those screws face up towards the wing skin??
Thanks,
Vin...
Thanks,
Vin...
12-05-2014, 11:04 AM
#38
Thread Starter
The bracket has a vertical hole dimensioned for a 2-56 socket head screw.
We supply carbon fiber plates that fasten the servo vertically for the vertical securing option ( when there is no lateral access to the 4 #6 self tapping screws ).
In that case the #6self tapping screws are not used. The servo is inserted in the brackets vertically, then secured with the cabon tab and two 2-56 socket head screws.
The clearance on the servo being less than 2/10 mm the fit is very strong like this. This is a very easy and fast method.
However, for super large jets where you need maximum load bearing, the 4 #6 sheet metal screws need to be used.
In that case, the vertical hole is used to bolt the bracket to a plate glued on the skin.
Here is how Joe Grice mounted his servos on the large F-105.
The servo in position:
The skin plate:
The servo side:
We supply carbon fiber plates that fasten the servo vertically for the vertical securing option ( when there is no lateral access to the 4 #6 self tapping screws ).
In that case the #6self tapping screws are not used. The servo is inserted in the brackets vertically, then secured with the cabon tab and two 2-56 socket head screws.
The clearance on the servo being less than 2/10 mm the fit is very strong like this. This is a very easy and fast method.
However, for super large jets where you need maximum load bearing, the 4 #6 sheet metal screws need to be used.
In that case, the vertical hole is used to bolt the bracket to a plate glued on the skin.
Here is how Joe Grice mounted his servos on the large F-105.
The servo in position:
The skin plate:
The servo side:
06-01-2015, 03:42 AM
#39
Thread Starter
I have finalized the brackets for some of the Spektrum servos.
The micro size a4030 HV:
The standard size suitable for the a6040 and a6150 HV series:
These have been put through destructive tests.
The standard size bracket has an internal shear strength of 500 lbs and a gluing interface shear strength of 286 lbs on hysol 9462. Maximum holding torque, 1700 oz.in
The micro size has an internal shear strength of 200 lbs and gluing interface shear strength of 145 lbs on hysol 9462. Maximum holding torque, 900 oz.in.
The user manual has been updated to include these sizes:
http://www.geohei.lu/olin/data/model...%20rev%203.pdf
The micro size a4030 HV:
The standard size suitable for the a6040 and a6150 HV series:
These have been put through destructive tests.
The standard size bracket has an internal shear strength of 500 lbs and a gluing interface shear strength of 286 lbs on hysol 9462. Maximum holding torque, 1700 oz.in
The micro size has an internal shear strength of 200 lbs and gluing interface shear strength of 145 lbs on hysol 9462. Maximum holding torque, 900 oz.in.
The user manual has been updated to include these sizes:
http://www.geohei.lu/olin/data/model...%20rev%203.pdf
