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Honda 1.8L on RV6A Now Flying!

Ross,

Yes the R18 actually as the same thing and like you said I suspect all modern engines have this. In fact the R18 has two separate loops and both enter the suctions side of the T-stat housing to get warm water on the spring side of the T-stat to get it open when the temp reaches the preset level. One loop serves the heater core and the other in the R18 Honda goes to the Transmission cooler. both are 5/8 hoses. I plan to use one for the heater core like you did.

Charlie
 
Engine Mount continued

I am going to attach a few photos of the engine mount process.

The one below is of the mount being rough fitted to my RV6A airframe. The mount is only tackwelded and the top cross pieces are actually still loose. I left them loose so I could make some last minute small adjustments as needed. I was happy that I am only a few millimeters off of where I want to be. Nothing that I cannot correct with a few extra washers to get it just right.

The tubes are 4130 chromoly 3/4" and 0.49 wall. It will be primed and painted once the tig welding is completed.

http://www.halie.com/oPl.jpg

The next photos is of the rear of the mount. Noticed the top cross pieces are missing. Also notice the grey colored mounting plates. These are made with 6061-t6 aluminum plate. Notice the top one has a piece of angle iron on it. This provides the rigidity needed to take the load. The bottom one has significant plate support on the front side that is not seen from this side view. You can see these lower plate supports on the forward side of the bottom plate in the picture above.

http://www.halie.com/oPr.jpg

The last pic is the frame being tack welded on the jig. The bottom plate has the lower section of a Vans OEM mount as well as weldments for the rest of the frame positioned to replicate the pattern of the firewall. The top section is the jig that has the pattern of of the grey colored plates on the engine. The jig was created to properly orient the engine on the airframe. In my case it was a bit more challenging because I had to also position it to match a cowling I made. The end result will give me about 7-8 inches aft of the engine and also 6" forward of the engine. Saber Manufacturing is making me a 6" extension. It will have the 4" bolt pattern on the engine side to match the pattern on the Viking Aircraft engine gearbox, and a SAE#1 prop pattern on the prop side.

http://www.halie.com/oPw.jpg


Feel free to ask questions.

Charlie
 
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New custom mount installed

I tig welded the new mount and now have it installed on the RV6A. Most of the components have been removed during the move from the engine stand to the airframe.

There are 2 pics below.

This link below is of the engine on the mount on the RV6a.

http://www.halie.com/oP3.jpg

The next link below is view of the mount before the engine was mounted to it.

http://www.halie.com/oP4.jpg

I sent back the "standard" duty gearbox to Viking Aircraft Engines so I could upgrade to his "turbo" heavy duty gearbox. I hope to have it in about a week.

Ill be anxious to see how well I got it properly oriented in the Yaw, Pitch axis as it relates to the air frame; as well as centered to the cowling that I had previously made (from scratch) for a different engine installation I had planned. I'll have to wait and see how that actually turns out when the new gearbox shows up. My rough install showed I was 3-4mm off in the yaw axis but I am OK with that. I can correct that with a washer on the mount.

Feel free to ask questions or let me know if the links do not work.

Charlie
 
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Are you going to use Anti-Splat nose gear? The nose gear strut just looks a little light for the job at hand.

Glad to see engine move from test stand to the airframe.

Very interesting to follow your progress...
 
Are you going to use Anti-Splat nose gear? The nose gear strut just looks a little light for the job at hand.

Glad to see engine move from test stand to the airframe.

Very interesting to follow your progress...

Glad to hear a few folks are following the project. It gives me some encouragement to do the posts.

As far as weight and balance goes, I don't have the numbers yet to really make an informed decision. But I will certainly consider it. I look forward to that day when I have those numbers and when I have them I will certainly compare them against the proven set ups of all who have gone before me. It is great to have such a large community who are willing to share their experiences, good and bad, so the rest of us can benefit from the information.

Good flying to you.

Charlie
 
Guilty on sneaking around here to. This thread and Ross's EFI ans Suby links where my lecture over X-mas. I absolutely admire what you are doing. Affordable, fuel efficient engines are very important to me. I can't imagine myself burning 7 gallons of AVGAS just for fun here in Germany. Actual price for one gallon is 9,80$. I am wondering if it would be possible to put a Honda 1,6 iDtec Diesel Engine in a RV-9. Of corse this is to far from realistic.

I wish you success. Please keep on posting.
 
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Dan,

I am certainly open to that. If you or others have recommendations for an engineer feel free to share that.

Another option is to test it to failure....

Charlie
 
Guilty on sneaking around here to. This thread and Ross's EFI ans Suby links where my lecture over X-mas. I absolutely admire what you are doing. Affordable, fuel efficient engines are very important to me. I can't imagine myself burning 7 gallons of AVGAS just for fun here in Germany. Actual price for one gallon is 9,80$. I am wondering if it would be possible to put a Honda 1,6 iDtec Diesel Engine in a RV-9. Of corse this is to far from realistic.

I wish you success. Please keep on posting.

Tom,

Thank you for your kind words. There are many many folks lurking on this thread. I see you have built a Savannagh. Great airplane. As far as Honda diesel goes, I do not know much about that engine. But there are several Honda 1.5L Direct Injection gasoline engines in Zenith 750's...If that interests you PM me....

Charlie
 
Dan,
<snip>
Another option is to test it to failure....

Charlie

That is at the bottom the list of good ideas. Testing requires known loads and cycles. Then a test is designed to induce loads and cycles to exceed that which is known. If you knew the loads and cycles, you would have designed it to meet those and would not have gotten the suggestion to consult a knowledgable person in this area.

As a person who has spent decades in doing just this, the least energy (and most successful) course of action is consulting one who already designs these components.

I might start with Ken Krueger, not knowing anyone else who is in the consulting business.

No disrespect Charlie, I just like your posts (keep them coming) and wish to see you succeed in this venture. Hate to see you see you fail with injury.
 
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That is at the bottom the list of good ideas. Testing requires known loads and cycles. Then a test is designed to induce loads and cycles to exceed that which is known. If you knew the loads and cycles, you would have designed it to meet those and would not have gotten the suggestion to consult a knowledgable person in this area.

As a person who has spent decades in doing just this, the least energy (and most successful) course of action is consulting one who already designs these components.

I might start with Ken Krueger, not knowing anyone else who is in the consulting business.

No disrespect Charlie, I just like your posts (keep them coming) and wish to see you succeed in this venture. Hate to see you see you fail with injury.

Bill,

Thanks. If you have Ken's contact info please PM me.

I am never closed minded to folks especially ones who are real "been there done that" people.

I have a few contacts who I respect and some have suggested to add triangulation support (laterally) on the top to strengthen the roll axis stress. This would be fairly easy to add.

Absent the comment above, the mount follows the design of several conical mounts in production in that each of the 4 main points of contact are triangulated from 2 separate points with 4130 tubing that is size equal to or greater than these mounts.

Charlie
 
I am never closed minded to folks especially ones who are real "been there done that" people.

Hey, I've built at least one poorly designed engine mount. Those are the lessons that stick the best.

the mount follows the design of several conical mounts in production...

Let's take a look. Got a link?

.... in that each of the 4 main points of contact are triangulated from 2 separate points with 4130 tubing that is size equal to or greater than these mounts.

Which brings us to the crux of the problem. Using two points to fixate a third point only works in two dimensions. Put another way, it constrains the third point only within the plane formed by the points.

In addition, it appears you're treating the mounting plates on the back of the engine as truss elements. Can't do that, given rubber between the plates and the other elements.

The lower mounts and landing gear tube illustrate both issues. Assume force 1 is applied to the landing gear socket, as it would be when the nose wheel is in contact with the earth. The result is force 2, pushing points A and B outboard. The gray aluminum mount plate cannot constrain force 2 in any significant way because of the rubber mount donuts. Nor is force 2 constrained by triangulation to points C and D, or to E and F. Using one side for illustration, force 2 is outside the plane defined by A-C-D, by nearly 90 degrees.

Load%201.jpg


One possible solution would be the addition of three tubes. Again using one side for illustration, the addition of tube A-G completes the triangulation of point A; consider A-C-D and A-D-G. Tube B-H does the same on the opposite side. The presence of A-D-G and B-H-F means Tube A-B is not strictly necessary, but I'm pretty sure it would improve stiffness.

Tube%20addition.jpg


There may be a more efficient approach, and there are other issues to address. Get with a pro.
 
Hey Dan,

No argument, but given what you can see in 'certified' mounts, it's easy to see why he'd think it was ok the way it is. Ex: the Piper Cub mount:
https://www.wagaero.com/repair-station/engine-mount-repair/piper/piper-cub-j-4-engine-mount-repair.html

which does use the motor itself (on the other side of the mount cushions) for the last leg of the triangles. (Not the only example; just easy to find quickly.) I can only assume that the range of bending allowed by the mount cushions is considered acceptable.

Just guessing, but I'd bet that the reason the C-D element is missing on the Cub mount is that it's bolted to a steel tube fuselage that contains that element, but it's required on the Van's mount because the aluminum angle at that point in the RV fuselage can't handle the 'cripple' (compression) load.

The Cub mount is really scary looking to me, but it's survived longer than most of us have, so it must be ok *in its intended location/application*.

Details, details...

Charlie
 
No argument, but given what you can see in 'certified' mounts, it's easy to see why he'd think it was ok the way it is. Ex: the Piper Cub mount:

Sure, plenty of similar examples. Recall I asked (the other) Charlie to show us what he was using for models.

Here's the thing; good triangulation is more about stiffness than strength. A structure can be strong enough, yet be too flexible.

Remember the "bad mount" I designed? It was more than strong enough, and had reasonable triangulation. However, it was not stiff enough given the pitch/yaw vibratory block motion of an inline three, the result being a wobble of the prop disk, similar in many respects to the famous Lockheed Electra whirl mode: https://lessonslearned.faa.gov/ll_main.cfm?TabID=2&LLID=7&LLTypeID=2

Given a one-shot eyeball design, a fella should always go for stiffness.

EngCompt.JPG


Just guessing, but I'd bet that the reason the C-D element is missing on the Cub mount is that it's bolted to a steel tube fuselage that contains that element, but it's required on the Van's mount because the aluminum angle at that point in the RV fuselage can't handle the 'cripple' (compression) load.

Fuselage provides C-D for the RV mounts, just like the Cub.
 
Hey, I've built at least one poorly designed engine mount. Those are the lessons that stick the best.



Let's take a look. Got a link?



Which brings us to the crux of the problem. Using two points to fixate a third point only works in two dimensions. Put another way, it constrains the third point only within the plane formed by the points.

In addition, it appears you're treating the mounting plates on the back of the engine as truss elements. Can't do that, given rubber between the plates and the other elements.

The lower mounts and landing gear tube illustrate both issues. Assume force 1 is applied to the landing gear socket, as it would be when the nose wheel is in contact with the earth. The result is force 2, pushing points A and B outboard. The gray aluminum mount plate cannot constrain force 2 in any significant way because of the rubber mount donuts. Nor is force 2 constrained by triangulation to points C and D, or to E and F. Using one side for illustration, force 2 is outside the plane defined by A-C-D, by nearly 90 degrees.

Load%201.jpg


One possible solution would be the addition of three tubes. Again using one side for illustration, the addition of tube A-G completes the triangulation of point A; consider A-C-D and A-D-G. Tube B-H does the same on the opposite side. The presence of A-D-G and B-H-F means Tube A-B is not strictly necessary, but I'm pretty sure it would improve stiffness.

Tube%20addition.jpg


There may be a more efficient approach, and there are other issues to address. Get with a pro.

Dan,

I appreciate the time you (and others) took to dig in to this and offer help.

The pic you were using was of the mount before it was finished. (I actually did not remember post it.)

I have added more support and I will post pics of the updated mount soon. I hope I get enough time out in the shop to at least get the changes tack welded. But it may be next weekend before I get time to share more pictures.

In short I have added more support to the top to take lateral (roll axis) force, and I could easily add that lower #2 cross tube to relieve lateral stress on the two lower bushings from the nose gear. Vertical pressure in this area is well supported with the members that go upwards.

More to follow.....

Charlie
 
The stock mount for my -7 has a vertical element between the top & bottom fuselage attach points, on both sides. I'm pretty sure the -6 mount has them, as well. Is that not where you drew the C-D line?

(rotary) Charlie
 
The stock mount for my -7 has a vertical element between the top & bottom fuselage attach points, on both sides. I'm pretty sure the -6 mount has them, as well. Is that not where you drew the C-D line?

(rotary) Charlie

I think the vertical tubes you're talking about are to provide additional stiffness for the landing gear sockets. They do not appear to be present on the -A model mounts.

Skylor
 
I think the vertical tubes you're talking about are to provide additional stiffness for the landing gear sockets. They do not appear to be present on the -A model mounts.

Skylor

You're right; I'd never paid attention to the -A mount, but it doesn't have that element in it.
 
......and wouldn't you know today would be the day my tig welder seems to have died. Ugh!

Would one of you please call my wife and explain to her why I really need a new one, because I sure don't!!!!

I am trying to see some humor in all of this....

Charlie.
 
Charlie,

I?m really enjoying your posts, and I admire your open attitude. With your willingness to share your journey publicly and also accept advice, I have no doubt you?ll end up with an interesting and safe conversion and I?m looking forward to watching your progress.
 
Thank you for your kind words and encouragement. I think a lot of people (especially me) benefit from people who are willing to share ideas and lessons learned.

While I don't always agree with what everyone says, I do consider all the comments. It can be hard, if not impossible to really know if someone has the knowledge to support their advice, but I have enough folks I can bounce various ideas off of to usually feel confident about my final decision.

Another benefit is that almost everyone who has participated in this thread does not get personal with criticism and that makes it really helpful. Life is just too short to go down that road.

Last, I also encourage folks to not forget the "E" in EAA. Thankfully we are free to make (most) of our own decisions and that is a good thing.

Good flying to you.

Charlie
 
Agreed. I?m interested to see where you end up with your engine mount. It?s not an area you read too much about on here. Dan H looks like he has some good ideas to start. Uncharted territory - remember to enjoy the journey, we?ll all be watching and learning something.
 
Hope you get your welder fixed or replaced soon Charlie and we're looking forward to your progress updates on the engine. Putting the E in Experimental is something we don't see enough of here IMO.
 
The pic you were using was of the mount before it was finished.

I know. That's why I did not comment on the upper mounts. All comments dealt with the lower mounts and gear tube structure, which appear to be the same in all photos.

....and I could easily add that lower #2 cross tube to relieve lateral stress on the two lower bushings from the nose gear. Vertical pressure in this area is well supported with the members that go upwards.

Proposed tube A-B, if installed alone, does not triangulate the mount points. Let's again look at just the lower part of the mount.

The mount plane we wish to triangulate is defined in red. The primary load of interest is transverse (side to side), as would be applied by at least three of the six available degrees of freedom, lateral, torsional, and yaw:

Subject%20Plane.jpg


Here is that plane in planform, viewed from the top, looking down.

Mount%20Plane.jpg


As currently configured (top), a transverse force applied at A or B is not constrained.

Adding tube A-B (center) constrains the gear load previously described as (2), but does not triangulate the mount points.

Instead, add tubes A-G and B-H (bottom). Points A and B are triangulated.

Adding tube A-B in addition to A-G and B-H (bottom right) adds stiffness when considering spreading load (2, illustrated in post 162) from the forward end of the gear tube. Without A-B, load 2 is reacted back to points D, G, H, and F, which is all that is really necessary. However, A-B supports that particular load directly; the short load path is how stiffness is achieved. Moving to detail design, tube A-B is mostly a tension member, so it can probably be reduced in diameter or wall thickness.

While I don't always agree with what everyone says, I do consider all the comments. It can be hard, if not impossible to really know if someone has the knowledge to support their advice, but I have enough folks I can bounce various ideas off of to usually feel confident about my final decision.

Allow me to bring out the soapbox for a moment. The axiom you want is "Trust but verify". Don't just believe anyone, including me. Instead, consider the information. Use it as a starting point and dig for supporting fact. First and best question is usually "Does it adhere to fundamental physical principles?" Yes, sometimes the process is hard. Do it anyway.
 
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eng mt

Been following your post as I plan on honda on my Zenith 701. on another note,not to confuse issue, but on my RV4/subie 2.5,Iused factory engine mt
for Lycoming, an made up brackets to go from subie to existing factory
Lycoming mount ! Fortunately Viking makes eng mount for honda to Zenith !
Tom
 
I will tackle several things in this one post.

1) My new welder should be here by next weekend. Yes it was a fun discussion with my wonderful wife.

2) Thanks Tomcat, some of the lower part of this mount is an actual "vans" part. Also, I do like the Zenith series and truth be known, I hope a 750 SD is my 2nd kit to built, but that is O.T. so I wont go there.

3) Dan. Thanks for clarifying the comment about "top" vs "Bottom". I do agree that it would be good to add additional members to gain more strength laterally - both top and bottom. As fate would have it there is a in interference conflict with the hall effect sensor on the crank pulley where the proposed lower "A+B" cross member will be. But as you mentioned, this is primarily serves as a "tension" support mechanism and with that in mind, I am comfortable with this particular piece being angle "iron" in shape. While I agree adding "G" and "H" (in addition to "A+B") would add even more support, I (at this stage) am comfortable with adding just "A+B" but not "G+H" to the structure. Ill explain, part of the reason is that the length of the members that lead to "A+B" are considerably shorter than as you have drawn - hence, their moment arm (so to speak) are stronger in the lateral sense. I hope that makes sense to the readers.

As far as the top members go, there will be even more lateral support members. I will post pics when these new members are installed.

Last, I would like some help knowing how to post pics so you can see them without having to click on links like I do using "Halie" dot com. PM or post here either way.

Thank you to all who offer suggestions and support. It keeps me going.

Charlie
 
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While I agree adding "G" and "H" (in addition to "A+B") would add even more support, I (at this stage) am comfortable with adding just "A+B" but not "G+H" to the structure.

I assume you mean "...comfortable with adding just A-B, but not A-G and B-H to the structure."

Last, I would like some help knowing how to post pics so you can see them without having to click on links like I do using "Halie" dot com.

Resize them to 800 pixels wide, 1000 max, before uploading to Halie, then insert
after it.
 
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I assume you mean "...comfortable with adding just A-B, but not A-G and B-H to the structure."

YES. correct.



Resize them to 800 pixels wide, 1000 max, before uploading to Halie, then insert
after it.

Super, I will try that hope it works.

Thank you.

Charlie
 
Here is a good primer for structural concepts. You can buy it at all the usual places:

https://www.amazon.com/Structures-Things-Dont-Fall-Down-ebook/dp/B009G1PHP2

Have you studied similar structures designed by professionals? For example, consider the RV-6A, RV-7A, RV-8A, and RV-9A motor mounts. Here are two photos borrowed from the web. Note the incorporation of members A-G and B-H. There is no member A-B; it is not required, and without members A-G and B-H it would not triangulate the lower mount structure.

RV-6A

RV-6A.jpg


RV-7A

RV7A.JPG


Two lower dynafocal rings triangulated in both the vertical and horizontal plane:

RV-6A%20Triangulation.jpg
 
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3) Dan. Thanks for clarifying the comment about "top" vs "Bottom". I do agree that it would be good to add additional members to gain more strength laterally - both top and bottom. As fate would have it there is a in interference conflict with the hall effect sensor on the crank pulley where the proposed lower "A+B" cross member will be. But as you mentioned, this is primarily serves as a "tension" support mechanism and with that in mind, I am comfortable with this particular piece being angle "iron" in shape. While I agree adding "G" and "H" (in addition to "A+B") would add even more support, I (at this stage) am comfortable with adding just "A+B" but not "G+H" to the structure. Ill explain, part of the reason is that the length of the members that lead to "A+B" are considerably shorter than as you have drawn - hence, their moment arm (so to speak) are stronger in the lateral sense. I hope that makes sense to the readers.

When I first saw the photos of your engine mount I had immediate concerns but refrained from posting because any time I do post in a thread related to alternative power it seems to be taken as an attack on the practice (the reality is I would love to see a proven, viable alternative to a Lycoming for RV's but I digress.....)
I fully agree with Dan and I hope you will seriously consider his suggestions. As it is now, I think your engine mount has some serious compromises when compared to the standard mount. Hopefully an interference problem wont be allowed to drive your engineering process.... instead think of it as a problem that requires being creative.
 
Best practice is to triangulate all engine pickup points although I've seen a number of designs with multiple airplanes flying successfully for years which didn't and had cringeworthy tube layouts.

The last thing you need is the engine departing the airframe, so play this area safe. You can move the crank sensor to the flywheel end of the engine if there is tube interference at the rear. As Scott says, don't let this drive any compromises in the tube layout of the mount. I can supply you with alternate sensors and magnets if you need to re-position things.
 
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When I first saw the photos of your engine mount I had immediate concerns but refrained from posting because any time I do post in a thread related to alternative power it seems to be taken as an attack on the practice (the reality is I would love to see a proven, viable alternative to a Lycoming for RV's but I digress.....)
I fully agree with Dan and I hope you will seriously consider his suggestions. As it is now, I think your engine mount has some serious compromises when compared to the standard mount. Hopefully an interference problem wont be allowed to drive your engineering process.... instead think of it as a problem that requires being creative.

Scott,

Thanks for posting. The pic that is referenced the most was of the mount as it was being built was not the final product.

I will post some new pics with the additional support members in a week or two.

Charlie
 
Best practice is to triangulate all engine pickup points although I've seen a number of designs with multiple airplanes flying successfully for years which didn't and had cringeworthy tube layouts.

The last thing you need is the engine departing the airframe, so play this area safe. You can move the crank sensor to the flywheel end of the engine if there is tube interference at the rear. As Scott says, don't let this drive any compromises in the tube layout of the mount. I can supply you with alternate sensors and magnets if you need to re-position things.

Ross,

Thanks for the offer on the hall effect, but there is no need to relocate it.
 
To all,

As far as the A-B, A-G, B-H goes I am still studying the issue. I hope to get some time on the project this weekend.

I also need to get out some better pics so people can get a better understanding of the angles of the mount for what they really are. Which is particularly valuable to the decision as it relates to the A-G, and B-H members.

It is a bit hard to explain without pictures but because the "bolt" tubes (section of tube the bolts pass through where the members attach) between the A-G and B-H are virtually pointing at each other, think parallel. ... welding a tube between would be less than ideal as it relates to the attachment angle. Another option is to use gussets...or....move the G and H over to the top of the top of the nose gear mount support. That also is not ideal as it puts compression pressure on the top of the nose gear mount which accentuates the pressure it receives on landing.

Ill try to get some more pics soon.

P.S. when it comes to tension force, I do not consider an angle shaped member as a compromise of strength compared to a tube shaped member. Anyone care to dig up and post those numbers?

Good discussions!

Charlie
 
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Here is a better view of the lower section of the mount. There has been some reference and diagrams to the the "A" and "B" points and I thought it would be good to see it from a better view.

Note there are three colored lines, light blue, dark blue and brown.

While I agree you can always add additional triangulated members such as the adding another member where the brown line is drawn. I did want to shed some light on the triangulation that exist in the sturcture by showing the light blue and dark blue lines.

oWc.jpg


Sorry the image is a bit oversize. I will work to get it smaller next time. Also, the point labeled "G" really should have been "H" but I know everyone gets the picture.

Charlie

Charlie
 
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For halie.com pics, insert "scale/xx/" immediately after "... halie.com/", where "xx" is the percent scaling you desire. So it looks like "www.halie.com/scale/xx/oWc.jpg"

Here is an example using your picture at 65% scaling:
oWc.jpg

Carl,

Great tip, thanks.

Charlie

(I miss Arlingtons "hay-days of the 80's!)
 
I did want to shed some light on the triangulation that exist in the sturcture by showing the light blue and dark blue lines.

One more time.

One%20More%20Time.JPG


The tubes marked in red have nothing to do with triangulating points A and B. They support the gear tube, and rely on good fixation of A and B to do it well. To fixate A and B, you need to add members A-G and B-H.

Also, the point labeled "G" really should have been "H" but I know everyone gets the picture.

You labeled G correctly.
 
I think we have kicked this can (lower mount support topic) down the road far enough that out of respect to those who want to keep up with my project I say we move on to some updates on the project. (But I will post some pics on the new members on the top of the mount because that got overshadowed and I want to circle back to it. But due to other commitments it will be a few weeks.)

UPDATE: I happy to report that I got the new Heavy Duty "Turbo" PSRU gearbox from Viking. I am very impressed with what I see. It uses larger bearings, larger back plate and an improve venting system with a very nice glass window to easily check oil reservoir levels. Viking recommended the upgrade since I am planning on using a turbo. They were very quick to get it sent out. I expect this set up to produce up to and may be over 160hp.

I have not mounted it yet but I will probably be able to post pics of it this weekend.

Charlie
 
P.S. when it comes to tension force, I do not consider an angle shaped member as a compromise of strength compared to a tube shaped member. Anyone care to dig up and post those numbers?

Good discussions!

Charlie

I would agree with that, but vibration will be another matter. You can use thinner wall or smaller diameter tube for a tension only link. Just for the esthetics. I see Ken Krueger post here sometimes as "Sky Designs". A static stick modeling of this should not take much computer work and will answer all the questions of loading.

When my SAE mini BAJA team did our design ('77), it was before ready availability of FEA models. My team member with the structural/frame assignment came in with a model made out of coat hangers and soldered together. It was wonderful because we could see the stiffness and load it by hand. We immediately found the weak area and added a cross brace. It was Auburn's only National 1st place.
 
I would agree with that, but vibration will be another matter. You can use thinner wall or smaller diameter tube for a tension only link. Just for the esthetics. I see Ken Krueger post here sometimes as "Sky Designs". A static stick modeling of this should not take much computer work and will answer all the questions of loading.

When my SAE mini BAJA team did our design ('77), it was before ready availability of FEA models. My team member with the structural/frame assignment came in with a model made out of coat hangers and soldered together. It was wonderful because we could see the stiffness and load it by hand. We immediately found the weak area and added a cross brace. It was Auburn's only National 1st place.

Bill

Sounds like a great project, I bet it was super fun! Thanks for sharing .
 
New mount lower support members

Well I actually got time in the shop to day to add those A-G, B-H members.

Here is a pic. I know this will be obvious to many, but if you are new to the thread, I was encouraged to add the members that are the unpainted tubes. They are only roughed in. Not welded. I hope to get the welder next weekend.

oWo.jpg



Here is a shot of the roughed in new members on top. They are also only taped in place. The blue triangles are were there will be gussets.

oWz.jpg
 
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Here is a shot of the roughed in new members on top. They are also only taped in place. The blue triangles are were there will be gussets.

Charlie, let's have some fun.

Imagine you're driving your Jeep along a jungle trail, when you come to a piranha-infested river. The helpful natives have erected a bridge. You must decide. Is it safe to drive across, or have the natives set a trap for the invaders?

The%20Bridge%201.jpg


Your co-driver, being a master of gearbox design, insists the bridge is fine, so you attempt to drive across. Sadly, it collapses, and you are both eaten by the piranhas. The natives are greatly amused.

The%20Bridge%202.jpg


The natives were clever. They built a Warren truss, but left out one member. Without it, the result is a concentrated bending load.

Let's return to airplanes. First, thank you for reconsidering your lower mount triangulation. We all want you to succeed.

Now about those upper mount points. Previously we talked about how rubber mount points make the aluminum plate (bolted across the back of the engine) ineffective as a tension or compression member in a truss. Slobovian Charlie quite correctly noted that many mounts do depend on the engine to complete a truss, which is true. In fact, many don't even bother to create a truss. Although such structures may be strong enough to avoid the piranhas, they will exhibit low stiffness. Flexible structures are a wild card you don't want.

Like the jungle bridge, completion of the Warren truss requires one more member:

Warren%20Truss.jpg


The gussets? Ditch 'em. Without the above truss member, they add little stiffness while creating a stress concentration. With the added truss member in place, they are entirely unnecessary.
 
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The new bottom tubes look good.

I'd be concerned the top angled tubes meeting the middle of the unsupported lateral tube near the firewall won't be as stiff as if could be. Ideally, you'd have another pickup point there tied into substantial firewall structure, that being tied into the upper longerons. Since this is a lot of work, Dan's suggestion is an easier fix for less weight.

Dan, thank you for adding an interesting storyline to a rather dry subject.:)
 
Dan, Ross,

Thanks for the comments.

For the sake of the natives I'll do it. It will be easy to add.

For all the fun we are having with this topic, IMHO it is not completely accurate to say there is no support between the top two posts now. We are all comfortable with the rubber mounts handling the 300+ lbs of the engine in all 3 axis of pressure, albeit most is tension/compression. So while I agree that adding another member between the posts is a good addition, it is not accurate to say there is no support there without it.

Just think, if the engine set up doesn't work I can always put this mount in the bed of a truck to use as a hitch for a 38ft 5th wheel trailer, wa da ya think?

Charlie
 
How much does it weight ?

One of the questions, I get asked the most is "How much does it weigh"?

While having so much fun with the mount I took the time to weigh the engine "as is". Some of you who have been following this thread will know that I showed a pic of the engine without any components, just the long block and I am pretty sure it came in at 201 bls.

Right now it is at 276 lbs. This includes:

1) T3/T4 Turbo and adapter mount plate. (Probably 16lbs +/- 2)
2) Alternator
3) New idler pulley.
4) Starter
5) Throttle Body
6) Intake
7) starter ring gear the PSRU mount plate
8) Top, Bottom, and both side mount plates
9) Misc stuff

For me, this is not bad at all. Here's the pic.

oWI.jpg


Here is the Turbo side as weighed.

oWM.jpg


Charlie
 
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Ross,

Yeah, it's not the most powerful engine, nor the lightest, but "bang for the buck" it has a lot going for it. Especially knowing it is entering its 12 year in production, that in itself is remarkable. And...it has a 2.0L stroked version still in production as well. (added - and you can buy complete engines with less than 5k miles on them for $800 all day long...)

The Achilles Heel in these "Alternative" engines is often the PSRU - gearbox), and sometimes the ECU. Fortunately SDS EFI makes the ECU a breeze. I hope the PSRU from Viking shows it can stand the test of time. I am happy with it so far. I will post the pics of the new unit soon.

Charlie
 
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May I ask what happend to your "old" PSRU?
And what did it cost you? The Viking Homepage list just one PSRU for 3000USD and for me it is not clear what is included in that price... What about Damper, Mountingplate ...
 
May I ask what happend to your "old" PSRU?
And what did it cost you? The Viking Homepage list just one PSRU for 3000USD and for me it is not clear what is included in that price... What about Damper, Mountingplate ...

Tom

Viking offered me the HD PSRU for $1000 plus a return on my old unit. I thought this was fair so I jumped on it.

I know I paid extra for the 3 prong flange that bolts on the crank but I honestly cannot remember how much, I want to say $200. But it is important to remember that my project is far from what Viking typically does. I think the Guibo unit was extra too but I cannot remember how much, may be $100?

I also want to point out that the bolt pattern for the PSRU gearbox was not an exact match for my engine. Four of the 5 standoffs were a direct fit, but I had to machine a piece to pick up that 5th bolt.....

Let me know if you have any other questions. Happy to share what I am doing.

.......now if that welder would just show up!!!

Charlie
 
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