Dominator Shock Woes

[PPG Doug]

Hey guys/gals.

I'm new to the Dominator, but I have a silly question. My Dominator's left air shock is not lifting when I apply the air compressor to it. It only lifts about 1 1/2" from bottomed out, compared to maybe 4" on the other side.

Am I overlooking something really simple?

Thanks!

[ToddP]

Push up on your mast while filling will help the shocks extend out. The shock will fill all the way up.

[Racer]

I used to use this kind of shock on my racecar and the way we would set them is jack up car to where the shock was fully extended, Fill with nitrogen to the desired pressure and that was it. Hope this helps

[PPG Doug]

Thanks guys. I did try to rock the entire gyro and essentially lift up to alleviate some of the weight, but maybe it just wasn't enough. This Dom. has a Subaru on it so it is heavy.

I'll try another way.

Thanks.

[mark treidel]

Doug, I have the same issue with my shocks & the heavier 912. I did as Todd suggested & pressureized them with nitrogen. They seem to hold up longer, especially in colder weather because nitrogen doesnt expand/contract like air does. The problem here is introducing enough pressure to the shock. I ended up using a high pressure canister that Bill Clem has for his unit. Without it, mine would not hold up. I tried several pressure units but none are strong enough...quite the dilema. I have been patiently waiting for someone here on the Forum to come up with a good 'spring over' alternative & a part number to order. Problem is they dont seem to have one. I think a good infinate adjustable shock with a spring is the answer. We just have to figure out what configuration to use & how much each spring should support depending on the aircraft weight. Most of the combinations I've seen are in the $300-$500 range. I would buy them if only I could find the right one. Perhaps someone could weigh in on this that already has the model on their machine and give us the specs & part numbers from where they were purchased....(please)...

[ToddP]

I'm there with you Mark. I've been hoping and looking for a long time wishing there was an alternative. I really don't like my leaky air shocks. I'm just a little reluctant to start ordering shocks only to find out they don't work.

[Racer]

I may be able to help you guys out. I had the same problem with the shocks leaking down and being inconsistent so I changed to a coil over racing shock that I love. They are an aluminum bodied racing shock that you can adjust a gazillion different ways. You can order any spring ratings you want as well as get any valving you can dream up, you can even get one rate of valving for shock extension and another rate of valving for shock compression.
If you are looking for cheap economy shocks these are not for you because these are all custom built, But I believe these have great potential for those willing to spend a few bucks.
Mark, If you are willing I will bring some of these up and let you test them out on your Dominator to see what you think, Then at least we will have a starting point and can figure out what would work best, Let me know

[ezeddie]

Doug,
I just pick it up by the teeder bolt, well, just take the weight off the wheels. B/4 I air up. This winter it seems to leek out easly..........

eddie.............

[mark treidel]

Thanks Todd, I believe the other guys here on the forum are looking for the same thing you spoke of in the above post. Would you be able to post the name of the company who custom makes your model of shock & springs so others can possibly order them too. A specific part number would be a great starting point with a pressure (poundage) limit also. I will be in touch...thanks again......

[GyroRon]

You guys either are doing something wrong or something. I don't have these problems with my Dominators and I have had three of them.

[Racer]

Gyroron, after time the seals wear out on those oil/air shocks and they start to bleed off ( Not all of them, only some ) sounds to me like these guys have some leaker's.

The shock brand name is Avco racing shocks, I looked for a web sight but could not find one, I assume they do not have one. I will take some pics today and post them so everybody can see what they look like. I order them through a local dealer here in town, In worst case scenario I could order them here and send them to you guys, but I will try to find a dealer list so you can order them directly.

I cannot post part #'s on the shocks I am talking about because the way you order them is
1. which shock body you want
2. what valving you want extending
3. what valving you want compressing

Then you order the spring perches and what rate of springs you want.

that is how you order the shock then it takes about 3 to 4 weeks to get it because it is built to your specs. Once we figure out the best combo I will make the info public knowledge for all who are interested.

Once we get the best valving setup for the shocks it should work for all the dominator's, You can order different spring rates for the different weight motors everybody is using.

[rfi]

I used spring/shocks from Azusa Engineering (azusaeng.com). They have 12 inch center to center and have 3 inches of travel at full compression. The 1700-236 and 1700-246 models are rated at 730 pounds at full compression.

I built a dozen gyros and modified a lot more with the Azusa spring/shocks. I even built a suspension system for the RAF 2000 with those shocks.

Azusa does not sell retail. You must buy from a dealer. Check their web site for the dealer nearest you. Cost is around $40 each.

[gyromike]

The shocks Todd is talking about are made by AFCO. They are a racing shock for Circle Track cars. If you've been to Bensen Days, you've seen them on Davey Seace's tandem Dominator.

Here is the web site (http://www.afabcorp.com/AFCO_Dynatech_USbrake/merchant.mvc?Screen=CTGY&Store_Code=A&Category_Code=ct_r-alum-sm-th), and Davey uses the aluminum small body threaded shock. The springs (http://www.afabcorp.com/AFCO_Dynatech_USbrake/merchant.mvc?Screen=CTGY&Store_Code=A&Category_Code=ct_small-coil-over) are listed on a seperate page.

http://www.afabcorp.com/AFCO_Dynatech_USbrake/r-alum-sb-thr_jpegs/rast-03.jpg

[mark treidel]

Thanks Mike...I've flown in Daves machine you refer to above. His shocks are the tool adjustable type but he doesn't recall where he got his springs (perhaps from a motorcycle) he said. I will try to see if this company can be of help & let the 'hive' know.

[Racer]

Thank You Mike, Yes that is them, I should have walked out to the shop first before I started typing... My Bad!
We will do some testing with a spare set of small body shocks I have and figure out what will work out best. For those who do not want to wait feel free to call the company, They are very helpful and friendly.

[MMorgan]

I'm still using the $59 air shocks and they do leak down after 2-3 months especially if machine sits for a while and not "exercised."

I bought a strut pump from Aircraft Tool Supply Company www.aircraft-tool.com for around $200. Put in regular shop air and it multiplies it in very short bursts and it works well. Takes 1-2 minutes to get 180-200 lbs. in shock.

[GyroRon]

All you need to air up the shocks - be it the cheap airshocks that come with the kit, or the expensive gas charged shocks I had on my last dominator - is a Co2 tank made for paintball guns and a hose adapter. Simple, cheap and super fast to use.

For the cheap airshocks that come on the gyro, a small 30$ 12 volt aircompressor works perfectly. They are slow but they will do up to 200 psi which most expensive shop type aircompressors won't get close to.

[mark treidel]

Ron, haven't tried your CO2 idea but the mini 12v compressor doesnt work on mine no matter how much time I leave it there. It just doesnt have the 'umpff' it takes to get them up to 200, even while lifting the machine to extend the shocks. Finally used a variable control valve 3000 lb. nitro bottle from Bill Clem. That Works!! But there has to be something more practical. Thats why we are looking for the adjustable oil dampened spring over models. Just wish I knew someone who has already done it instead of being the test dummy.

[GyroRon]

Mark, I had used the cheapy 12 volt compressors and they work fine for me. They work even better if you take the fitting off the end and use a fitting you have to manually hold on the valve, that way you don't loose any air pressure when removing the fitting after reaching the proper airpressure.

BTW the usual PSI is between 145 - 170 psi on these shocks.

[mark treidel]

Thanks Ron....I could not find any information about the pressure settings so I had to go by sight/feel. When I filled them with the nitrogen, I set them in the 180 range which pushed them all the way up but allowed for a bit of downward compression when I got in the seat. That seems to work well for me. The 'cheapie' compressors cant cut it up here very well....

[Ron E]

Try filling your tires and the air shocks with nitrogen. The nitrogen molecules are larger so leak-down takes longer. Pure nitrogen doesn't have the oxygen, ozone or moisture to cause corrosion (oxidation) of the rubber and steel materials.

I fill all my vehicle tires now with this stuff. Buy the gas at welding supply stores and rent or buy the tanks from them.. I bought a hose and regulator kit on-line for about $140. The regulator allows you to set the exact pressure you want, up to several hundred pounds. Fill the shocks safely in about 2 seconds!

[mark treidel]

Here are a couple of sites that I found from another threat posted by Phil Ruffin....thanks Phil.

http://gokartgalaxy.com/shock_absorbers.htm

http://www.azusaeng.com/shocks/shocks.html

[PPG Doug]

So, just how much PSI should I need to fill the shocks? I have not had the chance to take weight off of the shock and try to refill it yet. But, now I'm wondering if I simply don't have the uummph to do so with my compressor. My compressor is a little portable one that puts out about 110 psi. Is this my problem?

Thanks for all the responses everyone!

[dimwit]

Todd. What kind of pricetag are we looking at for the shocks your talking about? Only needs to be ball park figure.

[dimwit]

I've been toying around with the idea of using a coil over shock on the front rather than a leaf spring. Not that the leaf spring is not good enough. But on any design there is always room for improvment.
I'm posting pictures of what the plans call for, and what I'm thinking of doing.
Also has anyone already done this?41788

41789

[Early Bird Dave]

Just FYI, the Afco coil over shocks are well worth the price.
I switched out 3 weeks ago and it is a great mod that I wished I had
done earlier.
I'm still a rookie so anything that eliminates a duck walk is a plus.
I've got close to 100 landings on them already and I am amazed at the
difference they make.
David Seace is my hanger mate so his input was invaluable for the conversion.
For those wanting air shocks come see us at Bensen Days and we will sell you
some slightly used pairs cheap! :D

[Racer]

Just FYI, the Afco coil over shocks are well worth the price.
I switched out 3 weeks ago and it is a great mod that I wished I had
done earlier.
I'm still a rookie so anything that eliminates a duck walk is a plus.
I've got close to 100 landings on them already and I am amazed at the
difference they make.
David Seace is my hanger mate so his input was invaluable for the conversion.
For those wanting air shocks come see us at Bensen Days and we will sell you
some slightly used pairs cheap! :D

Dave, You actually did it Good Job! and thanks for the update.
Could we bug you for some pics?

[Timchick]

David,
Did you buy Kevin's Dominator?

PS. We were just in St. Augustine this weekend for the Steven Curtis Chapman concert at the Amphitheater. Didn't realize we had any gyro pilots there.

[gyromike]

Just FYI, the Afco coil over shocks are well worth the price.
I switched out 3 weeks ago and it is a great mod that I wished I had
done earlier.
I'm still a rookie so anything that eliminates a duck walk is a plus.
I've got close to 100 landings on them already and I am amazed at the
difference they make.
David Seace is my hanger mate so his input was invaluable for the conversion.
For those wanting air shocks come see us at Bensen Days and we will sell you
some slightly used pairs cheap! :D

What spring rate did you use?
How does it handle while taxiing around?

[Doug Riley]

I used the standard Dominator air shocks on my 912S powered tandem. At first, I pumped them up with a cigarette-lighter electric tire pump -- but its plastic gears soon wore out from the stress of pushing 200 psi. I switched to a high-quality hand pump from a bicycle shop. It was smaller and quieter and I even got a little ab workout pumping it up. Besides, it eliminated the need to pull the gyro up next to a car.

I used a target pressure of 215-220, figuring I'd lose 5-10 psi during the leakdown while unscrewing the hose. You do need to push the mast over to extend the shock while pumping it up.

I found that pressures lower than 200 produced too much sway when taxiing on uneven ground. The shocks should be at the top of their travel at one G, so the full travel is still in reserve to absorb deceleration loads on landing.

[mark treidel]

Doug, I ran into the exact same problems with mine. I ended up finding a happy medium of around 200#'s. Seems to keep them just stiff enough to have good extention and enough play at that pressure. By the way, the stock Monroe 803's on the Dominator are only rated for 150#'s maximum. I don't think I will ever be able to stop the leakage even using nitrogen. Just a $hi--- brand IMO.

[helipaddy]

I pump mine with a cheap car compressor. Pumps them up in about 20 secs. the guage just goes to 150psi on the pump so I keep going past the redline until I can see a bit of movement when I pull on the mast. they lose pressure every 2 months or so. I have a bicycle pump with a guage up to 200 PSI which I use to pump them up also.

[edee61]

Here`s what Ernie told me to use for my shocks on my Dominator. http://www.walmart.com/catalog/product.do?product_id=3992 Takes about 20 to 30 seconds for each shock. He said I needed 180 lb. So I run it up to 200 lb, lose a little removing clamp. I`ve had no problems with it.

[mark treidel]

Eddie, Dont wish to be the 'devils advocate' here but that pump doesn't quite get enough pressure for my shocks.....seems to give up shy of needed pressure. Also, I have another issue that probably differs from yours. I have a 12 gal. seat tank that sits very close to the shocks and the shrader valve of the shock faces the front of the gyro, thereby making it almost impossible to use that attachment with the 90* lock down on the end. It simply won't fit in the limited space. It's all I can do to get a standard air hose fitting on it with two fingers.
Monroe does make another shock which is 1 7/8" longer than the 803.....it's the 814. The mounts are the same & require no 'twist' on the shock (they mount at a true 90*) and the air valve faces outward so there is no issue in filling them. The only problem is that the mast clamp must be moved up to compensate the longer distance. On some units, this will contact the bottom of the hydro res. for the P/R. Caution must be used that the camber of the tires does not go outwards at the top under AUW. Ideally, they should be 1 - 2* inward from vertical. I wish I knew exactly what the spring load and shock type used on 'Cracker's' gyro was. Same for Dave Seaces' gyro. If somebody could chime in on this it would be benificial for all Dominator Drivers.........Thanks,

[scottessex]

Cracker has Chirco VW shocks with Harley springs,
very similar to the set up I have been using. You have to tailor the springs to your application, AUW, pilot weight, engine choice, etc.

[Early Bird Dave]

Racer: I dont have any pictures but it is the same set-up minus the air shocks.
I added Mustang front end rubber bushings which need to be cut down slightly
to keep the shock from sliding ay the ends. I can get pics if someone is trying
to do this but we prefer you come to Bensen days and see them.
Maybe we can have a shock install group party??!!:)

[Early Bird Dave]

Hey Tim, sorry I missed you! Next time you need a place to sleep over give us a yell, love to have you!
No I was in Wachula like almost every weekend pounding hours on my gyro. Great weather!!
Yes I bought Kevin's bird and I am working towards 100 hours flight time so I can take my wife up with me. I promised the morons, no wife before 100 hours...!

[Early Bird Dave]

Hi Mike! I used 135 per inch rate and I may still be a bit low. I have a 2 place with a sub so she weighs in empty about 565. She has now compressed her springs and sits low. Taxi's with some lean on turns. Balances mains more smoothly, lifts off more gently, and landings feel much more secure. Strong crosswinds are easier since a slight
caddywambas landing smooths right out. Confidence is higher, so you relax and don't death grip the stick. Great for a rookie trying to save on blade budgeting.:)

[Early Bird Dave]

Hi Mark. I modeled off of David Seace's gyro. He used the Afco 1674-6 small body threaded shock with 90# per inch spring. He says he wished his springs were a little more firm. His aircraft weighs approx. 425-450#. Again , this is empty weight and we are still struggling to get the math right for the gear geometry to spring rate.
The springs create an upforce when taking off and we had to add a stop between the gear, they work similar to a Butterfly on landing to a much smaller degree.

[GyroRon]

Eddie, Dont wish to be the 'devils advocate' here but that pump doesn't quite get enough pressure for my shocks.....seems to give up shy of needed pressure. Also, I have another issue that probably differs from yours. I have a 12 gal. seat tank that sits very close to the shocks and the shrader valve of the shock faces the front of the gyro, thereby making it almost impossible to use that attachment with the 90* lock down on the end. It simply won't fit in the limited space. It's all I can do to get a standard air hose fitting on it with two fingers.
Monroe does make another shock which is 1 7/8" longer than the 803.....it's the 814. The mounts are the same & require no 'twist' on the shock (they mount at a true 90*) and the air valve faces outward so there is no issue in filling them. The only problem is that the mast clamp must be moved up to compensate the longer distance. On some units, this will contact the bottom of the hydro res. for the P/R. Caution must be used that the camber of the tires does not go outwards at the top under AUW. Ideally, they should be 1 - 2* inward from vertical. I wish I knew exactly what the spring load and shock type used on 'Cracker's' gyro was. Same for Dave Seaces' gyro. If somebody could chime in on this it would be benificial for all Dominator Drivers.........Thanks,


My gyros shocks hold air fairly well, I only have to add air about once every 2 months or so. My first dominator I had to do it more often. I think some of the shocks work better than others....

Also I had the same pump edee61 posted a link to. Used it for a few years, worked great. Mine was modified by cutting off the clamp on end off the hose and replacing it with a normal type air fitting you would use to air up the tires on your car. You know the type you have to hold with firm pressure onto the valve as you fill up....

I got a different set up later to fill up the shocks that worked very good. It was a Co2 bottle meant to be used on paintball guns, and a flexible hose with a screw on fitting to screw onto the end of the schrader valve. Once screwed on, you just carefully and slowly unscrewed the on/off valve on the tank and it would air up the shocks quickly and easily. You would have to be careful though as that little tank packed serious pressure, I know it had to have over 600 psi in it as that was what it took for the shocks on my last dominator and this paintball tank filled them up easily.

[Timchick]

Hey Tim, sorry I missed you! Next time you need a place to sleep over give us a yell, love to have you!
No I was in Wachula like almost every weekend pounding hours on my gyro. Great weather!!
Yes I bought Kevin's bird and I am working towards 100 hours flight time so I can take my wife up with me. I promised the morons, no wife before 100 hours...!

I was in charge of getting the concert tickets and my wife was in charge of finding the hotel. We stayed at the Renaissance Resort at World Golf Village on the North side of St Augustine.

http://www.marriott.com/hotels/travel/jaxbr-the-renaissance-resort-at-world-golf-village/

For her the hotel is a large part of the vacation. You'll never hear the words "Motor Lodge" come out of her mouth.

[Early Bird Dave]

Hey Tim, I guess I'm lucky. My wife even likes camping at Wauchula, go figure?
Know the place you were at, very nice. I'm next to the airport if you come down U.S. 1 from World Golf Village.
I'd pour the first round but other then that the staff here is lacking!!:)

[Timchick]

David, Looking forward to flying with you at Bensen Days.

[robertstodaro]

well, today one of my shocks crapped out. I used to use 110 psi and today with 150 she would not extend with no weight on the gear. time for new shocks

[j bird]

The new set of Monroe's that came with my Dom, one of them never held air. Ernie gave me some tips, never worked. Got so digusted bought a new set, guess what, one shock won't hold air. I can't fu(king believe that a company like Monroe builds and sells air shocks that don't hold air.:noidea:

[robertstodaro]

changed my shocks the other day, what a beast of a job. It's a spot that could use a little redesign. but I'm keeping it.

[edypaul]

Robert

What type of shocks did you put on? Stock air shock ?

[robertstodaro]

The original ma803 Monroes, the ends are not parallel, but my copter mounts are.

If I have to do it again I'll drill the upper mount thru so that they do not have to be removed from the mast and use retainer bolts and stock hardware on the shock ends,

The lower end will get different shocks or I'll cut and reweld the landing gear leg end to match the angle of the off-set shock end.

I'm NOT going to trade it for and Aircomode but I would fix the mouth on the "Mona Lisa".