tande

My Feedback: (48)

Will someone please explain the argument against using "Hyde Softmounts", with gas engines?

JB Rekit

My Feedback: (3)

Don't know an argument against using them other than to save money or nose weight.

It will make everything last longer. Airframe, electronics, servos (gears). It will also help make the plane a little quieter w/o as much vibration going through the airframe.

I've been w/ and w/o and unless you are already very nose heavy, I would reccomend using one on a large plane (100cc or larger).
I guess it depends on how much you fly too. After 250 flights on my edge w/o a softmount, I put new gears in the servos, wing tube and antirotation dowels were very worn and had lots of play (wing and tail). Wheelpants were shot. Basically the whole plane is pretty worn out. A softmount will help make all of that last longer.

If it will take a few years to fly 300 times, you might just want to save the money, its up to you.

John

Call Merle...He will tell you all you need to know about them

Merle Hyde- 702-269-7829


John

ptgarcia

My Feedback: (36)

I had initialy soft mounted my Brison 3.2 on my Laser 200. There didn't seem to be much vibration. Then I ordered standoffs and hard mounted the Brison and there was considerably LESS vibration. Don't know why, just know there was. I think the majority of people here will tell you to NOT soft mount a gas engine. Again, I can't tell you why but with my limited experience I will always hard mount my gas engines. Good luck!

Antique

My Feedback: (4)

Soft mounts act like a spring, the engine shakes back and forth each way..The Hyde mount is soft enough to dampen the vibration..The one I saw needed a nose ring to keep the engine from sagging into the cowl opening, but worked well at high engine speeds....

dirtybird

My Feedback: (5)

Soft mounts transfer the stress from the aircraft to the engine. I have read that some manufactors will not honor the warrentee if the engine is soft mounted. I guess it depends on what you value the most - the aircraft or the engine.
Years ago I had a Veco 45 break the shaft. C Lee said that it was caused by my soft mount. ( It had not been crashed)

Rudeboy

I realise that Clarence Lee's opinion is valued very highly on your side of the pond... but an engine breaking a shaft because it is soft mounted?! Come on...
An engine breaking a shaft because of anything other than a severe crash is a manufacturing or design flaw. It should not break in normal use... wether it is soft mounted or not.

Vibration is an odd little thing.
Visual vibrations will often do much less harm than the ones you don't see.
A soft mounted engine will always shake more at some (low) rpm if it isn't dampened by hydraulic dampers or something like that. And it will very likely take the plane with it (shaking plane). But these vibes are almost harmless.
A hard mounted engine will tranfer ALL vibes to the airframe... so that includes the high frequency vibrations at full throttle that you don't see... and these are exactly the ones that are very harmful. They can eat up just about anything on your plane: servo's, control linkages, receivers, hinges, switches, the airframe itself... you name it, it can all suffer from vibration damage...

A properly setup soft mount system is always beneficial (except perhaps in racing where every last rpm counts). But it really requires a proper setup and you won't get that without some experimenting. There is no such thing like a bolt on system, because EVERY airplane-engine combination reacts differently.

I've been experimenting with this stuff a long time, and have had very good result. It just takes some time to get it right.

deputydog

Sorry Rudeboy but dirtybird is right! tande, you will get answers both ways on the subject and Rudeboy is correct about a special setup! A standard setup usually has specific rpm's where the vibration is actually worse than being hardmounted (something like a heli at low rpm!). Most stay away from them because the low level vibes is worse on the electronics. If an engine is evenly matched to the airframe, you will not notice much vibration at all. But over power a bird rediculously and you cant help but notice. Also dont run the plane without the wings on.

tande

My Feedback: (48)

Thanks Guys! for all the info.---very, very interesting

Kmot

My Feedback: (24)

Full size recip aircraft have the engines mounted on soft mounts, or "Lord Mounts" to be exact. They aren't breaking crankshafts. IMHO there should be no difference between 1:1 and 1:5 aircraft because vibration is vibration. Sure, there are different frequencies. But isolating vibration should never be a bad thing. I just don't understand the thinking that would claim that. Why bother to balance your props then? You're eliminating vibration!

-Tom

tkg

My Feedback: (1)

Balancing a prop helps to eliminate vibration, a soft mount just changes where the vibration is felt.
With a hard mount the vibration is soaked up by the plane and its components. With a soft mount the vibration is soaked up by all the threshing the engine does.
Which is why some engine warranties and most muffler warranties are void if a soft mount is used.
A Lord mount is designed to be used in compression. Look at how they are used in models, in tension. A full size has the mounts spread over a wide area giving them leverage to control the engine vibrations, a model has them all in a 6in. dia pattern.
Basically its a no win situtation, you eather thrash the airframe or you thrash the engine. This is why so many folks fly twins., they just have less vibration.

dirtybird

My Feedback: (5)

I would like to know if anyone has any test data on soft mounts. At the Toledo show one year I asked all the makers of soft mounts that were there if they any test data that proved thier mounts actually did anything. No one did!

ptgarcia

My Feedback: (36)

For a soft mount to work does it need to be "tuned" for each particular application? Or can they help with a wide range of vibrational frequencies?

NeoGenesis

My Feedback: (27)

Be careful on your big birds. A friend of ine had a 3w150 on his Aeroworks bipe. He's taking the soft mount off because under load, it's changing the thrust angle of the plane. It's changing it enough that it is noticable in flight.




Neo

Rudeboy

I have test data... but it is all empirical... I just got a "sixth sense" about soft mounts over the years... experience tells me something is likely to work, or not. But I still have to try it out, and often modify it to get it right.

Before I used soft mounts I had a receiver or two go bad, and a couple of servos (I'm speaking over a timespan of a couple of years). It was very obvious the damage was cause by one thing alone: vibrations. The importer who serviced one of the receivers confirmed that.
At that time I started using soft mounts and I haven't had this kind of damage since... coincidence? I don't think so. I still use hard mounted engines, mainly on smaller planes, but on anything bigger than .60 size I at least try to get it soft mounted.

Sure, mufflers tend to suffer on soft mounted engines... especailly on improper setups. But that is something that can be solved. Like I said before, it just takes some common sense and effort. Most of the time I make my own mufflers anyway, but stock stuff can be made to stay on too.

In my experience a soft mount indeed needs to be tuned to every particular engine-plane combination. You have "some" range, but it's not a wide range. If you setup a plane for a soft mounted .60 two stroke engine, and afterwards you just bolt on a 1.20 four stroke, you will get entirely different dampening characteristics.

All this of course, is my personal opinion and experience... There are milions of planes flying on hard mounts, and they are all fine... So you can live without soft mounts. But I like 'em.

3D Joy

Pattern planes use nose rings to get rid those thrust angle changes. Maybe easy on 23 cc engines but on a 150 cc, it is another story... Plane are not built to accomodate that kind of stuff.

tkg

My Feedback: (1)

There is a company in NJ called Cirrus Ventures that makes a soft mount that comes in several diameters and stiffness. This will alow some tuning.
You will have to find an ad they are not on the net.

JB Rekit

My Feedback: (3)

Thats why I would stick with a "Hyde" mount b/c he has been researching these for many years and has increased the diameter of the disk on the large gassers 100 - 240 cc to prevent the thrust angle changes, he also has the patent for them too and there are many other brands out there that will dampen the vibration, but may not give you what you are looking for as far as stiffness goes.

If you want to try something other than a Hyde mount, I would make sure someone else has had good luck w/ it or you may end up disapointed.

dirtybird

My Feedback: (5)

I would like to hear from someone that has real test data. Not just a sixth sense.
Someone that has mounted an accelerometer on a test airplane and made measurements with and without the soft mount. I did this about 30 years ago and found that the soft mount made no improvement that I could detect. The vibration was so high and at such high frequency that it went thru the mount just like it was solid. In those days I had only a .40 pylon racing engine. A big gas engine would produce different results I'm sure.
BYTW I measured about 100 g's on that .40. Thats peak to peak. I was using an oscilloscope for the indicator.

ptgarcia

My Feedback: (36)

I haven't seen any of his distributors advertise mounts for gas engines, only for larger 4-stroke glow engines. Does Hyde have a web page?

JB Rekit

My Feedback: (3)

He sells out of his home, but central hobbies sells his glow mounts on their website, you would have to call to find out if they sell the large ones.
http://www.centralhobbies.com/Engine...ydemounts.html

and here is a Q & A from Brisons site

Soft Mounts

Q: I have heard a lot of talk about soft mounts, good and bad. Should I use one for my single cylinder gas motor, and if so, which one?

A: Soft mounts on gas motors are probably one of the most controversial topics in giant scale. The problem with a single cylinder motor is the amount of harmonic vibration that resonates through the airframe. This is the damaging vibration. The movement of the motor on a soft mount is not the issue. Most people get nervous when they see a soft mount in action, due to the amount of engine movement.

What makes a soft mount work, is how much of this harmonic vibration the mount absorbs and does not pass through to the airframe. This is based on design, and the type of rubber used to make the soft mount. Many people have attempted to make their own soft mounts by just using a Lord mount and attaching it to a disc behind the motor. This is not an effective soft mount. For many years before twin engines became popular, TOC pilots used the Hydeâ„¢ soft mount, designed and patented by Meryle Hyde. Another good soft mount is manufactured by Scale Aviation.

captinjohn

How about using lord mount on a twin? That shoud be a good combo it seems. What is wrong with using lord mounts? Thanks, Capt,n

tkg

My Feedback: (1)

A simplistic discription A lord mount is a chunk of rubber with 2 bolt glued to it. It is designed to be pushed on. When its is pulled on sometimes the glue joint fails. No glue, no engine in plane.

captinjohn

Here is an idea I had....please don,t die laughing! Take a flat piece of aluminum and attach the engine mounts to it. Then use silicone rubber only and make a sandwich between plate and fire wall. The rubber being about 1/4 inch thick. Or use the silicone rubber to attach a thin piece of rubber about 3/16 thick. Again having the silicone rubber on both sides ...like a sandwich. Let it cure real good. Also for safety ...you could use 4 small hook type devises in four places just in case the rubber let loose. What do you think? Capt,n

captinjohn

TKG or ? Can it be said in a simplistic way... a gas engine when it fires, produces a faster or a more harsh explosion THAN glow engines when they fire...thus adding to the viabration problem? Just a guess on my part. Is a glow twin even smoother? Thanks Capt,n

tkg

My Feedback: (1)

In a simpilistic way...NO. The problem is basically that gas engines are much bigger.
Gas has a slower flame front than alcohol so in some ways is smother.