Engine Mount Rubbers
Posted: Sat Apr 01, 2023 10:09 pm
by Skippydiesel
Engine Run Time 30 hrs - approximately 25 flight hours.
I have the Mk2 Rotax/Sonex rail type engine mounting system.
In the short time the system has been in use, I have noticed an increase in engine movement (resulting in strike/rub marks on left side) probably happening at shut down.
Before you ask, in an attempt to “soften” the typical Rotax shut down movement - I take great pains to reduce engine speed to low idle (1800 rpm) and then “kill” each ignition individually, pausing briefly between actions.
Back to the mounting system - specifically the isolation rubbers - I would like to explore installing slightly harder rubbers - I believe the “rubbers” are supplied by Barry and that diffrent hardness/compressions are available. Am I correct in this belief?
If you have knowledge/experience of alternative rubbers please advise.
My thanks in anticipations.
Re: Engine Mount Rubbers
Posted: Mon Apr 03, 2023 5:23 pm
by Murray Parr
Skippydiesel wrote:Engine Run Time 30 hrs - approximately 25 flight hours.
I have the Mk2 Rotax/Sonex rail type engine mounting system.
In the short time the system has been in use, I have noticed an increase in engine movement (resulting in strike/rub marks on left side) probably happening at shut down.
Before you ask, in an attempt to “soften” the typical Rotax shut down movement - I take great pains to reduce engine speed to low idle (1800 rpm) and then “kill” each ignition individually, pausing briefly between actions.
Back to the mounting system - specifically the isolation rubbers - I would like to explore installing slightly harder rubbers - I believe the “rubbers” are supplied by Barry and that diffrent hardness/compressions are available. Am I correct in this belief?
If you have knowledge/experience of alternative rubbers please advise.
My thanks in anticipations.
22001 series Barry mounts come in medium and hard durometers but you can special order others, the ones Sonex use are Barry 22001-13 Green/White Hard Durometer Shock Mounts.
If you look through all the service bullitins, you will see 2 other additions to help with this, one is a simple addition of custom made washers and the other involves welding a brace to the engine mount but that requires removing the engine and some TIG welding.
Re: Engine Mount Rubbers
Posted: Mon Apr 03, 2023 6:34 pm
by Skippydiesel
“22001 series Barry mounts come in medium and hard durometers but you can special order others, the ones Sonex use are Barry 22001-13 Green/White Hard Durometer Shock Mounts.”
Thanks Murray - this was a large part of the information I was hoping to get.
Do you happen to know if there is a Barry Shock Mount hardness above 22001-13 Green/White Hard Durometer???
Re: Engine Mount Rubbers
Posted: Tue Apr 04, 2023 2:12 am
by Murray Parr
Skippydiesel wrote:[i]
Do you happen to know if there is a Barry Shock Mount hardness above 22001-13 Green/White Hard Durometer???
The only info I’ve found is on aircraft spruce website. It states “The standard neoprene elastomer is resistant to oil, and other materials are available on special order.”
Re: Engine Mount Rubbers
Posted: Tue Apr 04, 2023 7:55 am
by Skippydiesel
Murray Parr wrote:
Skippydiesel wrote:[i]
Do you happen to know if there is a Barry Shock Mount hardness above 22001-13 Green/White Hard Durometer???
The only info I’ve found is on aircraft spruce website. It states “The standard neoprene elastomer is resistant to oil, and other materials are available on special order.”
Your a good man Murray.
Without test data I don’t know what Aircraft Spruce are trying to say - sounds like a catch all phrase in leu of factual information.
I have write to Sonex, to get their input - let you know what they say.
Re: Engine Mount Rubbers
Posted: Sat Apr 08, 2023 5:36 pm
by Murray Parr
There is a Data sheet on Spruce website which shows 2 harder durometer bushes. Specs are on page 6. Part numbers 22001-14 & 22001-15
15-05688.pdf
(418.42 KiB) Downloaded 754 times
Re: Engine Mount Rubbers
Posted: Sat Apr 08, 2023 7:17 pm
by Skippydiesel
Murray Parr wrote:There is a Data sheet on Spruce website which shows 2 harder durometer bushes. Specs are on page 6. Part numbers 22001-14 & 22001-15
15-05688.pdf
Great information Murray.
Sonex respond to my enquiry - they are standing by their recommendation to use their supplemental washer kit SNX-SB-012
Re: Engine Mount Rubbers
Posted: Sun Apr 09, 2023 11:18 pm
by Murray Parr
[quote="Skippydiesel
Sonex respond to my enquiry - they are standing by their recommendation to use their supplemental washer kit SNX-SB-012[/quote]
I tried to install the washer kits on the weekend but the 1/2" ID ones don’t fit, the male Barry mount it is supposed to go over is more like .570" I will probably have to ream them out some.
Re: Engine Mount Rubbers
Posted: Mon Apr 10, 2023 7:52 am
by Skippydiesel
Murray Parr wrote:[quote="Skippydiesel
I tried to install the washer kits on the weekend but the 1/2" ID ones don’t fit, the male Barry mount it is supposed to go over is more like .570" I will probably have to ream them out some.
Veeeery interesting
Re: Engine Mount Rubbers
Posted: Mon Apr 10, 2023 6:41 pm
by Skippydiesel
Some more information from “Barry”
Sorry I don’t seem to be able to transfer the product information charts.
Re: Engine Mount Rubbers
Posted: Tue Apr 11, 2023 7:21 pm
by Skippydiesel
FYI -
Email from Hutchinson (Barry);
"Thank you for your interest in Hutchinson product.
Our recommendation regarding the isolation system would be to adhere to the engine manufacturer guidelines, however if you are looking for a stiffer isolator that has the same geometry it would be 22001-14 or 22001-15
The -14 is one step stiffer and the -15 is two steps stiffer.
Installing a stiffer mount will mean that you will control motion a little better, but will sacrifice some of the isolation efficiency.
Should you require a quotation for any of these parts for pricing and lead time please contact any of our value added distributors listed in the link below:"
https://hutchinsonai.com/distributors/
Re: Engine Mount Rubbers
Posted: Sat Dec 23, 2023 5:06 pm
by Skippydiesel
I have installed the Sonex stiffening washers and find that:
They have made little if any difference to my engine movement, which is still around 15-20mm at the top of the gearbox.
The rear, bottom, rubbers have moved/displaced, in particular the right-hand side.
I am now thinking that the next step, is to try the Barry Control Mounts 22001-14 being the next level of stiffness above the Sonex supplied 22001 - 13 mounts.
How are all the other users of the Sonex/Rotax adapter rails doing?
Re: Engine Mount Rubbers
Posted: Sun Dec 24, 2023 10:15 am
by Kai
An interesting question!
I am sure there are more than me and Skippy who would like to learn more about this.
Re: Engine Mount Rubbers
Posted: Wed Dec 27, 2023 6:06 pm
by Murray Parr
I was experiencing very heavy right yaw and also the same engine movement to the left and down (rub marks at the 4 o’clock position when looking at the cowl from the front). I was needing 3/4 to the floor right rudder input with any amount of power above 3000 rpm and slight left rudder without added power (I even ran out of rudder with a 5-knot x wind). After installing the upgraded washer kit, this improved somewhat, needing 1/2 to 2/3 rudder input under full power.
I now have 10 hours with this modification and the right yaw problem is worsening again, needing close to the original 3/4 right rudder input under full power. I can’t see any deformation of the rubbers but suspect they might be squashing a bit. I have the earlier B model Rotax tail dragger mount that only has the 1/4" bolts holding the MK2 bed mounts to it instead of the 5/16" the later ones have. I would like to add a couple of degrees right thrust to this setup and either go up one Durometer in stiffness or add a 3rd set in between the other 2 like the original design concept had. I really think Sonex should consider adding right thrust into this system as standard as it definitely needs it.
I tried to add a washer behind the left engine mount attach points at the firewall, however I couldn’t seem to be able to relieve the pressure on the bolts so I will most likely have to remove the engine to achieve this. Might be easier to re make the bed mounts with 2 degrees of right thrust.
Re: Engine Mount Rubbers
Posted: Wed Dec 27, 2023 8:27 pm
by Skippydiesel
Hi Murray.
All the best to you & yours for the coming year.
In comparison - my Sonex requires corrective right boot only during TO/CO.
I am still fiddling with small incremental changes to the trim (recently went backwards ) but very close to what I hope will be the final setting.
I have a small rudder trailing edge fixed trim, to correct a slight wings level yaw (bubble not quite centred) and my flaps are at slightly diffrent angles, to level the wings (hands off).
My aircraft has always required some up trim of the elevator (neutral when baggage compartment filled to 18Kg) To try & counter this, I have raised the front of the engine slightly, (before/after change aproximately 6mm tilt at prop tip) by adding 1 X 1mm flat washer to each front engine rubber stack . I think it has had a posative result, elevator up trim reduced.
I am hoping that the latest adjustments will in fact be my last & I can install the flap/fuselage gap seals (waiting for runway to dry out, so I can fly).
Does not apply to your aircraft but just letting any reader with/contemplating wing tanks - the quantity of fuel has a significant effect on lateral trim (as you may expect) so care must be taken, when transfering in flight, to try & keep fuel levels similar.
Re: Engine Mount Rubbers
Posted: Wed Dec 27, 2023 11:04 pm
by Murray Parr
Skippydiesel wrote:Hi Murray.
In comparison - my Sonex requires corrective right boot only during TO/CO.
How much rudder do you need, anything like the 3/4 of the way to the floor like mine needs?
Re: Engine Mount Rubbers
Posted: Wed Dec 27, 2023 11:40 pm
by Skippydiesel
Murray Parr wrote:
Skippydiesel wrote:Hi Murray.
In comparison - my Sonex requires corrective right boot only during TO/CO.How much rudder do you need, anything like the 3/4 of the way to the floor like mine needs?
To be honest I don’t really take much notice of the amount of corrective rudder. Seems to be much the same as my Zephyr. I expect to counter the turning effect of the prop/accelerating aircraft, so just roll with it.
Once I level out and she accelerates, resting (no force) my foot on the right rudder pedal, centres the ball - hopefully the small trim on the rudder will allow both my feet to be flat on the floor during nice level cruise.
Next flight, I will try and take notice of just how much right rudder I use in TO/CO.
Re: Engine Mount Rubbers
Posted: Thu Dec 28, 2023 9:18 am
by DCASonex
What is the direction of rotation of the Rotax prop? I need a lot of right rudder in my A series tail dragger Sonex with its CAMit engine. Have to hold some right rudder in climb, but none in cruise. You might just be seeing the effect of the prop. The more HP the greater the effect.
David A.
Re: Engine Mount Rubbers
Posted: Thu Dec 28, 2023 11:04 am
by 13brv3
Rotax prop turns clockwise viewed from the rear.
Re: Engine Mount Rubbers
Posted: Fri Dec 29, 2023 9:27 am
by DCASonex
Clockwise viewed from the rear is same as CAMit and Jabiru engines but I think is opposite that of AeroVee engines.
David A.
Re: Engine Mount Rubbers
Posted: Fri Dec 29, 2023 12:12 pm
by daleandee
DCASonex wrote:Clockwise viewed from the rear is same as CAMit and Jabiru engines but I think is opposite that of AeroVee engines.
David A.
Correct you are. The VW & Corvair both turn counter clockwise viewed from the cockpit and require left rudder for take-off.
Re: Engine Mount Rubbers
Posted: Fri Dec 29, 2023 12:40 pm
by Bryan Cotton
Between my helicopter time and all my Waiex time I’m going to be all screwed up if I ever get behind a lycasaurus again.
Re: Engine Mount Rubbers
Posted: Fri Dec 29, 2023 1:38 pm
by daleandee
Bryan Cotton wrote:Between my helicopter time and all my Waiex time I’m going to be all screwed up if I ever get behind a lycasaurus again.
Doubtful you’ll have a problem. I’ve had folks ask me how I deal with an engine that turns the “wrong way.” My reply is that I look out the window and tell the plane what I want it to do …
Dale
3.0 Corvair/Tailwheel
Re: Engine Mount Rubbers
Posted: Fri Dec 29, 2023 5:35 pm
by Skippydiesel
daleandee wrote:
Bryan Cotton wrote:Between my helicopter time and all my Waiex time I’m going to be all screwed up if I ever get behind a lycasaurus again.
Doubtful you’ll have a problem. I’ve had folks ask me how I deal with an engine that turns the “wrong way.” My reply is that I look out the window and tell the plane what I want it to do …
Dale
3.0 Corvair/Tailwheel
Agreed! I think it must be very close to instinktive, to keep the aircraft straight on TO/CO. Most pilots will correct any tendency to yaw/turn with the appropriate boot/input.
Re: Engine Mount Rubbers
Posted: Sun Dec 31, 2023 10:09 pm
by Skippydiesel
Murray Parr wrote:
Skippydiesel wrote:Hi Murray.
In comparison - my Sonex requires corrective right boot only during TO/CO.How much rudder do you need, anything like the 3/4 of the way to the floor like mine needs?
Made it to the New Year 
Have another hour or so since I last wrote - Murray: it’s hard for me to quantify the amount of corrective rudder on TO/CO - subjectively it doesn’t feel like very much ie what I would expect. I think, on my role/initial acceleration, I start with quite a bit boot, progressively lessens with speed/rudder authority. Still having some corrective boot throughout climb. Sorry to not be more objective. Wet weather inhibiting flying opps - will keep trying to observe my TO/CO actions.
Re: Engine Mount Rubbers
Posted: Fri Jan 05, 2024 8:32 pm
by Skippydiesel
I am pulling back (for the moment) from installing Barry Controls PN 22001-14 (stiffer mounts) and going for an interim modification: letter to Sonex-
"I may have a KISS solution, that does not involve stiffer mounts (at this time) with the added bonus of being both relatively quick & low cost, to implement.
Given that my particular installation Rotax 912 ULS + Airmaster CS and now 70 hrs engine time, there seems to be an issue with lateral movement, particularly in the rear/aft mounts.
My agriculture interpretation of how the Hutchinson Barry Controls 22001-13 mounts work (please feel free to correct me):
(For the purpose of discussion, I am separating & exaggerating, the function of the upper t & the lower mount. Realise that when correctly installed they work together)
• The upper part of the mount is responsible for vibration control.
• The lower part (donut) for movement control.
If I contain the lower mount (donut), in a “cupped washer” ie flat washer with vertical sides of suitable dimension. The donut movement would be better restricted ie resist the lateral movement of the mount and thus the rotational movement of the engine?
The Barry 22000 Snubbing Washer PN 9810145-01804 is 1.56” (39.624mm) x .391”(9.9314mm) x 0.90” (2.286 mm) - I can source the metric equivalent locally (40 x 10 x 2.6mm). To this I can weld a ring 8mm high (donut is .485” (12.319mm) high/thick), thus making a Cupped Snubbing Washer.
Alternatively:
The pre installation dimensions of the donut, is 1.31” (33.274mm) diagonally – I can make a Cupped Snubbing Washer, using a smaller 35 mm OD washer. This would, on installation/tightening up, restrict the sideways spread of the donut, resulting in some pre load/compression, that may further reduce the movement of the lower mount.
From my perspective the beauty of this is, it utilises the exiting mounts, just changes the way the lower donut is contained, can be installed without lifting/removing the engine and is low cost, it does not require a step into the engine mounting unknown."
Sonex refuse to comment.
Re: Engine Mount Rubbers
Posted: Fri Jan 05, 2024 8:45 pm
by Bryan Cotton
Can you blame them? They have not tested your solution. That is the beauty of experimental aviation, you can experiment all you want! I say give it a try and see.
Re: Engine Mount Rubbers
Posted: Fri Jan 05, 2024 11:17 pm
by Skippydiesel
Bryan Cotton wrote:Can you blame them? They have not tested your solution. That is the beauty of experimental aviation, you can experiment all you want! I say give it a try and see.
Yes I can & I do - I am no looking for them to tell me what to do, just give me the benefit of their knowledge/experince.
It’s up to me (the builder) to decide what to do/system/mods to implement.
Re: Engine Mount Rubbers
Posted: Sat Jan 06, 2024 5:00 am
by Skippydiesel
Moving forward!
Cupped Snub Washers have been installed and the engine run - everything looks good so living in hope. It would be great if I could send photos but never had any luck posting on this Forum - if you want photos, I can email them to you.
If weather Gods are with me, I will fly tomorrow.
I expect I will need to do quite a few hours with engine stop / starts, before I will know for sure if this very simple, low cost, nil risk modification(KISS) actually works to reduce engine lateral movement.
Re: Engine Mount Rubbers
Posted: Tue Jan 09, 2024 3:58 am
by Skippydiesel
Up Date:
2 X 1.5 hr flights, including about 6 touch & goes, same day (made the most of a break in the wet weather).
Bottom donuts all stayed in place, thanks to the Cupped Snub Washers.
Checked for excessive engine movement - Unfortunatly still too much.
Will purchase the next level stiffness of Barry Mounts PN 22001 -14.
Thinking I might start by replacing the -13 bottom donuts with the - 14 ie retaining the upper part of each - 13 mount, to preserve most of the original Sonex supplied installation.
If that doesn’t have the desired effect, will replace all of the Sonex -13 Barry Mounts with - 14’s
FYI: The Hutchinson/Barry Controls 22001 series only goes to - 15
Re: Engine Mount Rubbers
Posted: Tue Jan 09, 2024 4:33 pm
by Murray Parr
Hopefully you haven’t put your order in yet. I would like to get a set of the -14’s as well if you would like to go halves in the shipping.
Re: Engine Mount Rubbers
Posted: Wed Jan 10, 2024 6:37 am
by Skippydiesel
Phone you tomorrow Murray.
Have local supplier, going to give me a quote on the 14’s, when he gets back from annual holiday.
Re: Engine Mount Rubbers
Posted: Mon Jan 15, 2024 8:19 pm
by Skippydiesel
- “To try & preserve as much of the Sonex recommended system (22001-13) I will start by replacing the lower donuts with the 14 donuts and see if that has the desired effect.”
As a first step, I think the above is small, therefor may not result in sufficient movement reduction, so planning for the future (if needed);
-
The lateral movement, viewed from the cockpit, is to the left. With this in mind, could step two be replacing the two - 13 mounts, on the left side only, with the stiffer -14’s. What might be the negative effect of mixing two diffrent mount stiffness (Note: All 22001 mounts have the same dimensions)???
-
It seems that the rear/aft mounts are being subjected to more movement that the front two - Should I consider replacing the aft mounts with -14’s leaving the front two -13’s? As in 2, what might be the negative effects??
-
I will be purchasing 4 X - 14 mounts, so if step two/three don’t have the desired effect OR are skipped (due to advice/reflection) I will just replace all -13’s with -14’. Aside from checking for desired movement reduction, I would appreciate any advice on what I should monitor ??
Re: Engine Mount Rubbers
Posted: Thu Jan 18, 2024 5:13 am
by Skippydiesel
So I now have the Hutchinson/Barry Controls 22001-14’s fitted.
In my last post I had planned to substitute bits & pieces of - 14’ s only going to fully replace the -13"s as required, however the suppliers of the mounts advised that I just replace the -13’s completely. They seemed to know what they are talking about (30 years in the vibration control business) so went with their advice.
My Sonex is based on a grass strip, very wet at the moment, so no flying but hoping for hot dry weather over the next few days, to dry it out and then I will test/report back on the -14 mounts.
Re: Engine Mount Rubbers
Posted: Mon Jan 22, 2024 7:49 pm
by Skippydiesel
I have just done 1.4 hrs (2 engine starts) with the new Barry 22001-14 mounts (with my Cupped Snub Washers) in place .
Did not notice any major change in vibration/noise - possible very small increase in HF vibration through control stick.
Significant improvement (reduction) in lateral movement but still just marking witness tabs.
Next step - add the Sonex supplied spacer washers ACV-P54 -06 & -07 .
Re: Engine Mount Rubbers
Posted: Sun Feb 04, 2024 7:18 pm
by Skippydiesel
Have done 2.4 hrs with the new Sonex spacing washers (FYI: - they have a larger OD & are better machined, than the original supplied - they actually fit without further adjustment).
Again some improvement BUT still getting a touch, between rear right exhaust header and engine frame.
Options;
Go another step stiffer with the Barry Controls engine mounts to part number 22001-15
OR
Have the offending exhaust header reworked/new build, with slightly wider clearing curve - this last is possibly the best solution, as preserves the engine mount(s) vibration control while allowing damping movement BUT as is often the case, the most costly and time consuming
Re: Engine Mount Rubbers
Posted: Tue Feb 06, 2024 4:50 am
by Skippydiesel
It has been suggested, on another Forum, that making a strategic dent/depression, in the existing & offending exhaust pipe, to enhance the clearance between it & the frame, would have little impact on the cross sectional area of the pipe and therefore be unlikly to result in any engine performance loss - what thinks the Brains Trust??
If you agree with this proposal - how would you go about it? eg would you heat the pipe to plastic stage & then press/hammer in the depression, fill the pipe with sand to reduce unwanted distortion, do the aforementioned cold, etc
Re: Engine Mount Rubbers
Posted: Tue Feb 06, 2024 4:50 am
by Skippydiesel
It has been suggested, on another Forum, that making a strategic dent/depression, in the existing & offending exhaust pipe, to enhance the clearance between it & the frame, would have little impact on the cross sectional area of the pipe and therefore be unlikly to result in any engine performance loss - what thinks the Brains Trust??
If you agree with this proposal - how would you go about it? eg would you heat the pipe to plastic stage & then press/hammer in the depression, fill the pipe with sand to reduce unwanted distortion, do the aforementioned cold, etc
I will need a dent of about 10 mm in depth (in a 25 mm pipe) to be assured of not contacting the frame, in a poorly executed engine stop.
Have a look at this automotive experiment, to assess the effects of denting the exhaust system:
https://www.facebook.com/watch/?v=152724102049876
Re: Engine Mount Rubbers
Posted: Wed Apr 17, 2024 9:01 pm
by Skippydiesel
Update!
Finally bit the bullet and had my right rear exhaust header remade/adjusted, to give about 12mm extra clearance to the engine frame - seems to have done the trick. No evidence of brushing/touching in about 3 hrs of flying.
I have added one additional washer to the front two rubbers. This is to slightly change the prop thrust line, to reduce the amount of up elevator in cruise - seems to have worked. Carrying weight (max 18KG) in the luggage compartment behind the seat, has a similar effect.