Engine mount questions

[scottessex]

I am making the engine supports for the gyro, I was wondering if I need some sort of triangulation to help counteract torque on the engine mount boom, here is a couple of pics.

[GyroRon]

Yes I would add the bracing. Looks like you really cleaned up your workshop!!!

[scottessex]

I spent the last two weeks insulating, drywalling, painting the floor and adding a suspended ceiling. It is nice to work in now. Mary and I have been busy! I got gravel put down for the driveway too. we've been busy!

Would you just put one brace like the yellow lines, or would you brace it to the axle also, blue lines. The old engine mounted to the mast like a firewall mount, so I am unsure how much I need to keep the torque from twisting the mount boom.

[GyroRon]

I was kidding about your workshop, I thought those pics were taken from your place of work, Not until you mentioned it, did I see it WAS your AT HOME workshop! WOW what a transformation. If you treat the whole house as you did your shop, by next years SX days the place will be looking like it should be on MTV's show Cribs.

About the mount. I would go with the yellow only - not the blue - and ditch the rear bracket you got on there now and replace it with a bracket running down at a angle to the split keel custer cheekplates.

Any thoughts about the radiator mounting? I still think mounting above the engine back close to the prop will be best and cleanest installation.

[Chuck Irby]

Scott, the shop looks really great. It does look like a different place. Re the mounts, I would consider using the blue lines, but maybe spread them slightly at the bottom, and pull them in to the 2 x 2 at the top. I would also mount them without drilling any new holes in the axle tubing. It's difficult to tell in the pics exactly what you have now. Is the seat sufficiently supported?

It's looking really good Scott. I know you'll be happy to get it finished.

It's looking like you'll need to plan to meet Sonny on Sunday.

[birdy]

Gees Scott,your shed is cleaner than the local hospitol,not that that would be hard tho.

[GyroRon]

I Respectfully disagree with Chuck on the blue lines. I would not - and can not ever remember seeing others this way - brace the engine mount to the axle. The axle is prone to bending and breaking, and if so I would not want it to affect where the engine is going afterwards. The axle will flex, especially on your grass strip. If the engine is braced to the axle then everytime the axle flexes, the loads go into the entire engine mount system.

Here is some pics I have showing how engines are mounted on a few gyros. Remember that on a dominator the tube running down from the mount to the axle is not a fixed tube, it has a pivot point for the suspension.

[mrford61]

A couple of pics of how I changed mine. Before I fitted the current undercarriage / suspension (recognise it Birdy :D) I had a Tube axle like on Scotts with engine mount brace to the axle. One did in fact brake and the other developed a crack. (and my landings arent bad....well most anyway).

I changed it to this and as you can see I am prepared to forgo a little extra weight in the name of redundant strength. I also fitted a top mount from engine ,( EA81) to mast and also braces from the front of the engine mount to the mast.

BTW this is about where I am at with rebuilt after my bingle.

[scottessex]

More like this?

[Chuck Irby]

Scott, that won't really counteract the engine torque.

[GyroRon]

Scott that get's my vote. I am not a gyroplane designer either though. But for what it is worth, but that is clearly what the Dominator uses and I would say it is a well proven way of bracing the engine mount. Maybe one of the real gyro design experts could comment here with their two cents......

I think part of what attracts some to gyros is the fact that there is no wrong or right way of doing stuff like this engine mount. one way will have some advantages and disadvantages over another, but in most cases there IS more than one way to do it. Heck you could put on 4 or 5 more braces and have it strong enough to use to pull trucks out of the ditch when the roads get icy this winter, but then you run into a weight issue and alot of it is unneeded. When all else fails remember this KISS, you know what it stands for.

[GyroRon]

If you go with that design what do you see when viewed from the side and the back? Triangles.....

[Chuck Irby]

Scott, in Ron's pics in post #7, the first pic is not very clear, but it appears that there is some kind of engine support mounted to the axle tubing. You know what kind of landings you do, and only you can determine how much anti-torque support you want. For the type of takeoffs and landings that I do, even on grass, I wouldn't have a problem with engine supports mounted close to the center of the axle, but still far enough out to give me the support that I would want. But, only you know how much anti-torque support you want.

[scottessex]

That's why I am looking forward to going to ROC so I can take lots of pictures and get lots of Idea's.

Hey Chuck, sometimes I make good landings, and sometimes not so good ones! ---see pic--- :eek:

[GyroRon]

In the first Pic Chuck mentions, the engine is not supported by braces going to the Axle. The braces you see that look like they may go to the engine mount, go to the mast under the engine mount.

That gyro will be at ROC too, I believe.

[GyroRon]

Take a look at the gyrobee pics. They don't have any of these braces were discussing.

[scottessex]

I also noticed the gyrobee doesn't use any braces, but it was designed for a 447 rotax, Hmm?

[GyroRon]

Several bees fly with Rotax 503's and at least one is flying with a 582.

[scottessex]

That's right, Jay Boyce has a 582 on his.

[Chuck Irby]

Scott's original post: I am making the engine supports for the gyro, I was wondering if I need some sort of triangulation to help counteract torque on the engine mount boom, here is a couple of pics.

Ron, it seems that you have eluded Scott's original post to this thread, as none of your replies have addressed it. If Scott mounted the braces 6" from the center of the axle tubing, the flex that you mentioned earlier would be, at the most, just a few thousandths of an inch at that point, and he would get plenty of torque support for the engine mount.

I think Scott's original idea of suppling some torque support for the engine is a good one, and I was simply addressing his original idea.

[GyroRon]

Chuck I guess your right, I didn't fully read into Scotts main question in this thread. I took what he posted, quickly read it and percieved it as a basic question of which of his two ideas would be best.... the blue lines in that one picture or the yellow ones.

My responces to this point have only been to voice my opinion that based on common gyroplane construction, I can not remember ever seeing any gyros with any type of rigid attachment of the engine mounting bed to the axle of the gyro.

I also wanted to point out that, even though it may be very little at all as you pointed out, bracing the engine mount to the axle will allow or cause flexing stress to be placed upon the entire engine mounting bed. Even looking at Scotts picture he posted of his crash, if he mounted the engine to the axle as you suggest, there may have been little to no bending or damage to the mounts. So I guess that mounting to the axle won't be a major No No.

But once again, I still can not picture One gyro I can remember that has the engine mount rigidly attached to the axle. Going to ROC may be a good way for Scott to get more ideas.

My point in bringing the gyrobee into this discussion is to only shed light on the fact that there could be a point where the mount could end up as overkill. The gyrobee uses a simple mount with little bracing.

[scottessex]

Chuck, what i would like to see is the back of this one, this is the closest I have seen to what I am going to end up with, without the pod, but this looks like a drop keel KB3.

[Chuck Irby]

Ron, I agree with you in that I have never seen engine mount braces attached to the axle. However, from an engineering standpoint, the torque support would be far better than it would be if mounted to the drop keel. In addition, there would be less vertical movement of the engine support than in a tail first landing with the braces attached to the drop keel.

Scott, that is Richard Kennedy's machine. I think it's a modified AC. Email him for a pic. He's a nice guy and will help you any way he can, I'll bet. <richard@conwaycorp.net>

[GyroRon]

That looks like a modified KB-3 to me. The KB-3 is the only gyro I know of that uses a bent axle like that.

[Chuck Irby]

Ron, I'm sure you're probably correct. I just know it ain't a Dom. :D

How's it looking for the turnout for ROC?

[gyromike]

It is indeed a modified KB-3.
I believe it uses Don Parhams 8" drop keel cluster plates.
The tail is made of tube and fabric.

[Friendly]

scott , if you don't put something messy on that floor, I am going to stop reading this thread. I will consider it fiction!!!!

[Doug Riley]

Those who put heavy engines on Bensen frames often used to run braces from either the front or the rear of the engine mount down to the bolts in the axle that also attach the (steel) axle-to-mast angles. I did it myself on my VW-Bensen after finding that the engine tended to "sway" side-to-side. With those steel angles in place, that attachment point is not about to flex on landing (the axle will bend -- or break -- around that point).

Once you're flying, the axle doesn't bear any load other than the weight of the wheels. Engine torque is applied between the engine mounting point on the mast and the rotor. So the square mount tube with cluster plates to the mast handles the in-flight torque load. The down-braces are for landing and ground operations only.

The braces under the engine on a Bensen support the keel tube against tailwheel loads. You wouldn't expect these braces to do much in flight, either. Bensen's classic engine mount wisely puts most of the metal into the mount-to-mast (firewall) juncture, and only a couple pairs of 3/4" angles for the keel braces.

[GyroRon]

chuck the turn out for ROC is looking really good so far. May be the best turnout we have had in the last few years the way things are going so far. You coming?

[Chuck Irby]

Thank you Doug. I agree with what I think you said. :D

Ron, I would really like to go to ROC, but in all probability, I won't decide till the last minute.

[GyroRon]

Well it would not be the same if you don't come up to hang with us. I am very excited and am counting down the days!!! I thought you'd really have a blast at Bensen Days and I guess you did, but knowing you better now, I believe you will enjoy ROC much more. Your call, hope you decide to come.

[scottessex]

C'mon Chuck! I'll buy ya a beer! :D
And I'll cry in it because my gyro isn't flying yet. :mad:

If you decide please let us know so we will be able to look for you when you get there. ;)

[scottessex]

I think I figured it out, I will post pics shortly, Chuck you were right, I came up with a better Idea.
Ron, You will like the radiator mounting I came up with.
Mark, don't worry it will be messy soon enough, otherwise I am not working hard enough.
Thanks for all the help, and I did get some pics of the modified KB3. Thanks Chuck!